Dissimilatory Pathways for Sugars, Polyols, and Carboxylates?

TOC

Chapter 20

E. C. C. LIN

INTRODUCTION

It is a remarkable phenomenon that the various carbohydrates discovered to be utilizable by Escherichia coli and Salmonella typhimurium can all support growth in a mineral medium as the sole source of carbon and energy at a maximal rate seldom longer than 2 to 3 h per doubling at 37°C, since even in highly enriched media the doubling time cannot be shortened significantly below 0.5 h, at which point macromolecular synthesis and assembly become rate limiting. This is impressive because in natural environments a carbon and energy source virtually never appears singly. Hence, one would not expect strong selective pressure for the development of large capacities for individual pathways. Simple starvation would favor mutants that are amplified only in transport functions, not in entire pathways.

The catabolic repertoires for using carbon and energy sources are largely the same in E. coli and S. typhimurium. Nonetheless, significant differences are found even among the strains and substrains of each species. A few of the variations found among substrains may have resulted from selection under laboratory conditions or mutagenic treatment and cloning of the stocks. More likely, however, the variations reflect the polymorphisms that exist naturally in a strain. Numerous as the catabolites might be, the fundamental biochemical mechanisms for their breakdown are few. These mechanisms include phosphorylation, phosphorolysis, keto-enol isomerizations, removal or addition of hydrogen pairs, and aldol cleavage. It would not be surprising if future nucleotide sequence data showed that the majority of the genes specifying the special pathways came from duplicated genes for the glycolytic system and the pentose phosphate shunt at a time when life was anaerobic.

OLIGOSACCHARIDES AND DISACCHARIDES

E. coli

Maltose.

Over 80% of E. coli isolates ferment maltose (212). Certain strains can also grow on amylopectin [a backbone of glucosyl units in α(1→4) linkage with branches of 24 to 30 glucosyl units in α(1→6) linkage] through the action of an extracellular α-amylase that releases maltodextrins [linear glucosyl units in α(1→4) linkage], maltose, and glucose. However, strain K-12 utilizes only maltose and maltodextrins (646), as shown in Fig. 1. The substrates first traverse a selectively permeable channel across the outer membrane provided by the lamB protein (maltose porin, a trimer of 47,392 Da) which is anchored to the peptidoglycan layer. The exploitation of the external surface of the lamB product by phage lambda as an attachment site made the protein an object of special interest (110, 151, 218, 242, 243, 356, 378, 480, 537, 650, 694, 782, 784, 787, 840, 854, 880). Mutants lacking this protein are impaired in the transport of maltose at concentrations below 10 μM, whereas growth on maltotriose and larger oligomers is severely hampered (109, 840, 841). Inside the periplasm, the substrates are sequestered by a binding protein, the malE gene product (a monomer of 40,661 Da), which also serves as a receptor for chemotaxis (12, 107, 108, 208, 236, 329, 330, 331, 426, 687, 704, 806). The substrates are then delivered into the cytoplasm against a concentration gradient (904) with the participation of the malF (56,947 Da), malG (23,000 Da), and malK (40,700 Da) products (59, 258, 277, 808, 809, 810). Maltose and maltodextrins of up to seven glucopyranose units can be transported at about the same rate. Maltodextrins too large to be transported are nonetheless bound to the outer membrane (233). The entire transport process is believed to work in a bucket-brigade fashion, with the periplasmic protein coming into physical contact with the outer membrane protein and the inner membrane protein complex, giving little chance for the substrate to wander away (60, 89, 95, 234, 338, 889). The energy-requiring step of transport across the plasma membrane is not well understood (235, 705). An acetyl-coenzyme A-dependent enzyme (not encoded by the mal regulon) acetylates excess maltose in amylomaltase-defective mutants, and the product is excreted. Such a mechanism might serve as a safety valve during normal utilization of maltose and maltodextrins (90, 256).

Fig. 1Catabolic pathway for maltodextrins and maltose.

Source:

After the uptake of maltose or maltodextrin, a series of reshuffles are catalyzed by amylomaltase (a monomer of 71,000 Da) encoded by malQ. Maltose or larger oligomers act as acceptor molecules for the transfer of a 4-α-glucanosyl or glucosyl group from a donor no smaller than maltotriose, liberating free glucose from the reducing end of the donor (323, 574, 575, 645, 780, 791, 859, 902, 903). The glucose is probably converted by glucokinase to glucose 6-phosphate. Alternatively, maltodextrin phosphorylase (a dimer of 81,000 Da) encoded by malP can release glucose 1-phosphate from the sugar chains by phosphorolysis. The enzyme is most active on short linear α(1→4)-linked oligoglucosides and has the interesting property of being associated with two molecules of pyridoxal phosphate (like a number of other phosphorylases), the function of which is unknown in this context (206, 766, 786, 853).

Genes of the mal system, under positive control, cluster in two regions. The malA group at min 75 contains the malPQ operon and the malT activator gene, and the malB group at min 91 contains the malEFG operon and the operon comprising malK, lamB, and malM (function of gene product not yet discovered). Additional genes under the control of the malT activator proteins are being discovered. Because the malB region is involved in the substrate-uptake process, it would not be surprising if the malM gene product has a role in that function (355).

Raffinose.

The majority of E. coli isolates, although not strain K-12, grow on raffinose. Raffinose-negative strains with a lac system can mutate to grow on this trisaccharide (O-α-d-galactopyranosyl-[1→6]-α-d-glucopyranosyl-β-d-fructofuranoside) through constitutive expression of the lac operon, because β-galactoside permease acts on the trisaccharide as a fortuitous substrate. The α-galactosidase encoded by melA then liberates the galactose from the trisaccharide (40, 167, 212, 447; S. Schaefler, Bacteriol. Proc., p. 54, 1967; W. H. Holmes, Biochem. J. 106:31, 1968). Sucrose, the other product, is presumably excreted.

The ability of E. coli to grow rapidly on raffinose, however, is usually conferred by a special plasmid bearing a cluster of raf genes: rafD encoding an invertase, rafB encoding a permease, and rafA encoding an α-galactosidase (637, 819). Raffinose is first converted to galactose and sucrose by α-galactosidase, and the sucrose is then hydrolyzed by invertase. The plasmid-encoded α-galactosidase (a tetramer of an 82,000-Da subunit), distinct from the melA gene product, hydrolyzes methyl-α-d-galactoside, melibiose, and raffinose (773).

β-Galactoside Utilization through the lac System.

The great majority of E. coli strains are lactose positive (212). Ironically, the various mutants of strain ML (merde Lwoff by legend), which contributed so much to the understanding of enzyme induction through studies of its lactose system, were derived from a lactose-negative parent (572). The lac operon encodes proteins for the utilization of not only lactose but a variety of β-galactosides, including galactosyl-β-1,4-d-fructose and galactosyl-β-1,4-d-arabinose (35). The pathway (Fig. 2) starts with the reaction catalyzed by β-galactoside permease (lacY product), which was described in a landmark paper on bacterial membrane transport (707) and remains a classical model for the study of sugar permeation (410, 640, 921). Also, the permease was the first sugar transport system in bacteria shown to be driven by proton motive force (896, 897). Mutants with an energy-uncoupled permase cannot grow on lactose even though such a protein still catalyzes facilitated diffusion of the substrate. With such a limited function, autocatalytic induction fails probably for two reasons. (i) The substrate cannot be concentrated against a gradient. (ii) The true inducer derived from the substrate cannot be retained. If the lac operon is rendered constitutive, cells with the defective permease will grow normally on lactose at a concentration above 5 mM, the K_m of β-galactosidase (465, 916, 917, 933). Induction failure also occurs if the affinity of the permease for lactose is lowered (245). On the other hand, excessive lactose-transporting activity can lethally dissipate the proton motive force of a cell (209, 364, 656, 877, 913, 914). The broad specificity of the permease made it possible to detect β-galactosidase in vivo with chromogenic substrates, such as ortho-nitrophenyl-β-d-galactoside. This convenience greatly accelerated the genetic studies of the lac system (483). The wild-type permease can also transport sucrose against a concentration gradient (335), but mutations are necessary for the permease to transport maltose (807).

Fig. 2Catabolic pathways for D-galactose and D-galactosides.

Source:

Internalized substrates are hydrolyzed by β-galactosidase encoded by lacZ. The high molecular weight (a tetramer of subunits of 1,021 amino acid residues) partly explains why this enzyme can account for as much as 5% of the total cytoplasmic proteins in induced cells (278, 887, 952). Although the substrate specificity of the enzyme with respect to the aglycone moiety is remarkably broad, α-lactose (the hemiacetal of glucose in the α-anomeric configuration) is attacked with a lower K_m and a higher V _max than β-lactose (885). It is predominantly in the α configuration that lactose is found in milk. With lactose as substrate, the enzyme is more strongly activated by K⁺ than by Na⁺. The converse is true with ortho-nitrophenyl-β-d-galactoside as the substrate. The relative effects of the cations, however, depend on the strain from which the enzyme is isolated (160, 456, 483, 700, 886, 888). The enzyme catalyzes not only the hydrolysis of β-galactosides but also the rearrangement of lactose (probably some of the other substrates as well) to give allolactose (1-6-O-β-d-galactopyranosyl-d-glucose), which is a true inducer of the lac operon (120, 396, 586). Such transfer reactions can also result in the formation of several different trisaccharides (368).

A third protein (a dimer of about 270 amino acid residues) of the system, which transfers the acetyl group from acetyl-coenzyme A to the 6-OH of galactosides and thiogalactosides, is encoded by lacA, the gene most distal to the promoter. Substrates not readily attacked by β-galactosidase tend to be good substrates for the transacetylase, and vice versa. Indeed, lactose itself is not a substrate for acetylation (29, 115, 116, 246, 280, 598, 948, 949, 950, 951). Since acetylated galactosides escape from the cell and are not reaccumulated, the suggestion was made that the transacetylase serves as a detoxifying enzyme. Growth competition between isogenic lacA ⁺ and lacA cells in lactose media with or without a nonmetabolizable analog supported the hypothesis (36, 343, 915).

β-Galactoside Utilization through the ebg System.

Strain K-12 with a nonpolar deletion within lacZ can regain full ability to grow on lactose by a series of mutations recruiting a substitute β-galactosidase. The genetically altered enzyme is specified by the ebg (evolving β-galactosidase) locus at min 67.8 (44, 51, 135). Further studies revealed a cluster of three genes arranged and transcribed in clockwise order as the chromosome map is drawn: ebgR (encoding a repressor with a predicted molecular weight of 50,000), ebgA (encoding an evolved β-galactosidase that is a hexamer of six identical 120,000-Da subunits), and ebgB (encoding a 79,000-Da protein of unknown function). Although the ebgA-encoded enzyme is a very poor lactase, lactose is the most effective inducer (over 200-fold). Even at this level of induction, there is insufficient enzyme activity to permit growth on lactose. Mutations altering both the structure of the enzyme and the regulation of its synthesis are necessary to confer growth ability. Among the regulatory mutations, the majority enhanced the inducibility of the enzyme by lactose, whereas the minority caused constitutive synthesis of the novel enzyme. Since the ebg system does not provide a permease for lactose, growth requires the lacY-encoded permease, the presence of which is assured by supplying isopropyl 1-thio-β-d-galactoside in the medium (294, 296, 303, 304, 305, 307, 320). Mutants that grow on other galactosides were isolated. Selection on phenylgalactoside, a substrate but not an inducer, yielded mutants (ebgA ⁺ ebgR ^–) that synthesize the native enzyme constitutively. From such a mutant, which grew extremely slowly on methyl-β-d-galactoside, a derivative [ebgA(mg) ebgR ^–] with moderate growth rate on the compound was selected. A rich variety of other specificity changes was observed with the ebgA-encoded enzyme. For instance, mutations in class I sites of ebgA can raise the V _max on lactose to a high level which is accompanied by a drop of the V _max on lactulose and a slight increase in the V _max on galactosyl-β-d-arabinose. Mutations in class II sites (separated from class I sites by 1 kb, or about one-third of the gene) can enhance the V _max on lactose and lactulose to moderately high levels and on galactosyl-β-d-arabinose to a modest level. When class I mutants were selected for growth on lactulose and when class II mutants were selected for growth on galactosyl-d-arabinose, the resultant class IV mutants grew well on lactose, lactulose, and galactosyl-β-d-arabinose. These mutants were found to harbor both a mutation of the class I site and a mutation of the class II site. Only from a class IV mutant can a derivative that grows on lactobionate (galactosyl-d-gluconate) be isolated in a single step (295, 297, 299, 306). Even more impressive is the evolution of an ebgA-encoded enzyme acquiring the ability to catalyze the formation of allolactose from lactose by transgalactosylation. In such a mutant, growth on lactose is no longer dependent on the induction of the lacY permease by isopropyl 1-thio-β-d-galactoside (301, 727). Mutants in which the ebgR-encoded repressor increased its sensitivity to lactose as the inducer or responded to lactulose as an inducer were also isolated (298, 300). Nucleotide sequence analysis revealed a high degree of homology between lacI lacZY and ebgR ebgAB (831, 832). The ebg system has thus proven to be a fruitful model for studying the maturation of a regulated operon.

Melibiose and β-Galactosides.

E. coli K-12 and B, but not ML, grow on melibiose (6-O-α-d-galactopyranosyl-d-glucose), epimelibiose (6-O-α-d-galactopyranosyl-d-mannose), galactinol (1-O-α-d-galactopyranosyl-mesoinositol), melibiitol (6-O-α-d-galactopyranosyl-d-glucitol), galactosylglycerol (2-O-α-d-galactopyranosylglycerol), and probably many other α-galactosides with the aid of an inducible permease and an α-galactosidase, as depicted in Fig. 2 (513, 651). Among the α-galactosides, melibiose seems exceptional in that it can also induce and be transported by β-galactoside permease encoded by lacY. However, the compound cannot be hydrolyzed by β-galactosidase (512, 573, 682, 799). Melibiose permease (not inducible by lactose) is stable at 37°C in E. coli B, is labile at that temperature in strain K-12, and is apparently absent altogether at that temperature in strain ML (66, 651, 682). Cation-sugar cotransport mechanisms in prokaryotes are generally energized by the electrochemical gradient of protons, whereas those of eukaryotes are energized by the gradient of sodium ions. Melibiose permease of E. coli has the unusual property of being able to harness downhill electrochemical gradients of either protons or sodium ions for the uphill transport of the sugar (534, 861, 863, 864, 865, 866, 920) and thus appears to be at a branch point of evolution (918, 919). By selection for growth on melibiose in the presence of Li⁺, which inhibits H⁺-melibiose cotransport, mutant permeases that accept Li⁺ or Na⁺ but not H⁺ as the cation for symport were obtained (609, 801, 802, 846, 862). Enzymic hydrolysis of the α-galactosides is catalyzed by an enzyme (about 200 kDa) having the unusual property of requiring NAD and Mn²⁺ for activity (121, 122, 776). The two-step pathway (Fig. 2) is specified by the mel operon at min 93.4: the promoter-proximal gene A specifying the hydrolase and the promoter-distal gene B specifying the permease with a predicted molecular weight of about 50,000 (316, 775, 776, 947).

Trehalose.

Trehalose, 1-(α-d-glucopyranosyl)-α-d-glucopyranoside, is metabolized by an inducible pathway initiated by an inducible phosphoenolpyruvate phosphotransferase system (PTS) enzyme II. The product, trehalose 6-phosphate, is converted to glucose and glucose 6-phosphate by a specific hydrolase (Fig. 3). There is a constitutive hydrolase that acts on trehalose, but its true function is not known (553). The genetic locus specifying trehalose utilization is at min 26 (63). In strains able to utilize trehalose, the sugar also induces the mal system (782). The nature of the physiologically important pathway remains to be established (J. W. Lengeler, personal communication).

Fig. 3Catabolic pathways for D-glucosides.

Source:

Sucrose.

Almost one-half of the natural isolates of E. coli were reported to be sucrose positive (212). Some strains can give rise to sucrose-positive mutants, the phenotype of which is associated with an inducible α-glucosidase activity (43). Other strains are positive by virtue of harboring a conjugative scr ⁺-bearing plasmid (644, 819). The disaccharide is vectorially phosphorylated by enzyme II^Scr, and the product is converted to fructose and glucose 6-phosphate by a specific hydrolase (Fig. 3). The system is induced by fructose and is under repressor control (506, 774). Chromosomal integration of the scr ⁺ genes for sucrose utilization tends to occur at the dsd (min 50.5) locus specifying the structure of d-serine deaminase and the regulatory protein for its synthesis. When insertion occurs, the cell loses the ability to utilize d-serine as a carbon and energy source and becomes sensitive to growth inhibition by the amino acid. The relationship between the sucrose and d-serine traits is intriguing; the diploid F^? scr⁺/dsd ⁺ cannot synthesize d-serine deaminase (23).

S. typhimurium

Maltose.

Except for the fact that the lamB protein is not recognized by phage lambda as a receptor, the mal regulon appears to be similar to that of E. coli. The genes lamB (encoding the outer member protein) and malE (encoding the periplasmic protein) cluster at min 91 (647, 649, 650). The genes malQ (encoding amylomaltase) and malT (encoding the activator protein) cluster at min 74 (7, 648).

Lactose.

Most strains of S. typhimurium are lactose negative. Lactose-positive mutants were observed to arise, and some of these also acquired the ability to ferment cellobiose, salicin, and arbutin (770). However, the lactose-positive trait is generally attributable to plasmid-encoded genes. In a number of cases, the trait is found in pathogenic strains isolated from humans and domestic animals (53, 54, 201, 211, 230, 231, 281, 398, 460, 497, 839). Although the lac system from a number of different plasmids was found to be inducible and catabolite repressible and to include a β-galactoside permease and a β-galactosidase similar to those of E. coli, no thiogalactoside transacetylase was ever detected (287). This deficiency holds also for the lac operon in a plasmid from a clinical isolate of Yersinia enterocolitica, despite the homology with the E. coli operon (166). It would be interesting to find out whether the transposon Tn951 present in that plasmid is responsible for spreading the lactose-positive character to various enteric organisms not normally fermenting the sugar.

Melibiose.

The permease for melibiose for S. typhimurium was the first sodium-dependent sugar transport system discovered in bacteria (828, 858). The functionally associated α-galactosidase is also inducible by melibiose and is catabolite repressible (515).

Trehalose.

Trehalose is used through the sequential action of a specific enzyme II of the PTS and a trehalose-6-phosphate hydrolase in an inducible pathway (553). The genetic locus specifying trehalose utilization is at min 37 (755).

Sucrose.

Salmonella strains are typically sucrose negative, but plasmids that bear no known antibiotic resistance genes were observed to confer this trait to both S. typhimurium and E. coli (498, 927).

β-GLUCOSIDES: E. COLI

E. coli shows strain variation in the ability to utilize β-glucosides. It seems that most strains have functional genes for the metabolic pathway (Fig. 3), but in some strains, such as K-12, the structural genes cannot be expressed. Mutants that can grow on arbutin (4-hydroxyphenyl-β-d-glucopyranoside) or salicin (2-[hydroxymethyl]phenyl-β-d-glucopyranoside) arise spontaneously at a frequency of about 10^–5. In such cells, cis-dominant mutations occurred in the bglR site near the promoter, converting the bglCSB operon from the cryptic R ⁺ state to the inducible R state. The operon is located at min 83.4, and the three genes are transcribed counterclockwise from bglC, which appears to specify a positive regulator. The bglS locus encodes a specific enzyme II complex of the PTS which is believed to function also as a negative regulator of operon expression by interacting with the bglC product, thereby blocking its activating function. In cells with the inducible phenotype, the blocking effect can be overcome physiologically by the effector. The blocking effect can also be abolished genetically, by mutations in bglC (rare) or bglS (frequent), resulting in constitutive expression. The nature of the true inducer is not known. The gene bglB encodes phospho-β-glucosidase B. Mutations in this gene abolish the ability to use salicin but not the ability to use arbutin, which can be hydrolyzed by another enzyme, phospho-β-glucosidase A (247, 569, 680, 732, 750, 767, 768, 769; A. Wright, personal communication). The spontaneous activations of the cryptic bgl operon in strain K-12 often result from the introduction of the insertion elements IS1 or IS5 upstream of the existing promoter sequence. Evidently, fruitful insertions can occur between different neighboring base pairs, since Bgl⁺ mutants vary in their levels of operon expression. By a different mechanism, a specific base sequence upstream of the bgl operon makes it expressible under certain degrees of DNA superhelicity. Irrespective of the mechanism of its activation, expression of the functional operon still depends on inducer and cyclic AMP (cAMP)-cAMP receptor protein complex (cAMP-CRP complex). One may ask why the operon should fluctuate between two genetic states in a population. A suggestion was made that metabolically toxic substrates, such as those that can produce cyanides upon hydrolysis, may appear in the environment. When this occurs, it would be advantageous to have the bgl operon in the cryptic state (199, 703). The complexity of the system may be even greater if it is true that a product of the bglY gene (min 27) directly or indirectly causes the repression of the bglCSB operon and that mutation to the Bgl⁺ phenotype could only occur in strains lacking that repression (186, 187). Some strains are known to grow on esculin (6,7-dihydroxycoumarin-6-glucoside), presumably also through the mediation of the bgl system (118).

In strain K-12, phospho-β-glucosidase A, encoded by bglA, is synthesized constitutively. This enzyme hydrolyzes phosphorylated arbutin, not phosphorylated salicin. Although in some strains bglA is closely situated on the counterclockwise side of the bgl operon, the gene is not a part of the bgl operon. The expression of bglA is regulated by the product of the unlinked bglT, which is located at min 84.4. It remains to be discovered whether, in the absence of an active bgl operon, phospho-β-glucosidase A has a function of its own (681).

HEXOSES

E. coli

d-Glucose.

Vectorial phosphorylation by the PTS is responsible for the uptake of d-glucose (see chapter 75). The rate of d-glucose uptake can increase severalfold by growth on d-glucose or d-fructose, but the magnitude of induction is strain dependent (449, 450). The membrane-associated enzymes II for d-glucose and all of the other PTS substrates also serve as receptors for chemotaxis (11, 508; see chapter 75).

d-Fructose.

Growth on d-fructose induces an enzyme II^Fru-enzyme III^Fru complex of the PTS that phosphorylates the substrate at C-1. A second phosphorylation catalyzed by an ATP-dependent kinase then converts fructose 1-phosphate to fructose 1,6-bisphosphate, as indicated by Fig. 4 (249). The fruA (or ptsF) locus (see references 617 and 667 for the recommended genetic symbols for the individual pathways initiated by the PTS) at min 45.8 probably consists of an operon of three genes: fruA, encoding the protein II^Fru; fruB, encoding the protein III^Fru; and fruK, encoding the kinase. d-Fructose 1-phosphate entering through preinduced hexose phosphate permease (see Phosphorylated Sugars and Carboxylates, below) also causes induction. A mutant lacking the enzyme II complex fails to grow at low concentrations of d-fructose (<2 mM), and a mutant lacking the kinase is subject to growth inhibition by d-fructose as a result of fructose 1-phosphate accumulation (237, 238, 239, 399, 891).

Fig. 4Catabolic pathways for D-fructose, D-mannose, and L-sorbose.

Source:

d-Mannose.

An enzyme II^Man-enzyme III^Man complex of rather broad specificity is mostly responsible for growth on d-mannose (Fig. 4). This complex also catalyzes the phosphorylation of d-glucose and d-fructose. In a mutant defective in the system, some ability to grow on d-mannose is retained because of the side specificity of the enzyme II complex for d-glucose. On the other hand, in a fru(AB) mutant some ability to grow on d-fructose (>2 mM) is retained because of the side specificity of the enzyme II complex for d-mannose. In this case, d-fructose is phosphorylated at position 6. The enzyme II complex for mannose is encoded by the ptsLM operon at min 40.2: the gene L specifies protein III^Man and the gene M specifies protein II^Man (174, 224a, 240, 399, 400, 448, 649a, 892). The transmembrane enzyme II^Man serves as the entry channel for the DNA of phage lambda (216, 224a, 649a). Mannose 6-phosphate is converted to fructose 6-phosphate by an amphibolic isomerase that also has the function of synthesizing mannose 6-phosphate for capsular polysaccharide during growth on other carbon sources. Thus, it is not strange that the synthesis of the isomerase is coregulated with those of other enzymes involved in the construction of wall polysaccharides and that it is not inducible by d-mannose or catabolite repressible by glucose. The enzyme is encoded by manI (formerly manA) at min 35.7 (554, 555). Utilization of d-mannose, however, is catabolite repressible and dependent on the cAMP-CRP complex (253), but the specific regulation of ptsLM transcription has not been well characterized.

l-Sorbose.

Of 40 E. coli strains surveyed, 9 were found to grow on l-sorbose. Strains K-12, B, and C were not among the positives. However, the genetic determinant for the ability to grow on the sugar is transducible and found to be near metA at min 91 (934). The sor operon introduced into strain K-12 on a plasmid conferred the ability to utilize l-sorbose (Fig. 4), as follows. The sugar is first converted by an enzyme II^Sor (encoded by sorA) to l-sorbose 1-phosphate. The phosphorylated compound is then converted by an NAD(P)H-linked enzyme (encoded by sorB) to d-glucitol 6-phosphate, and the reduced compound is converted by an NAD-linked enzyme (encoded by sorD) to d-fructose 6-phosphate (822). Although strain K-12 does not grow on l-sorbose, two of its enzymes II (ptsG and fruA products) can act on the substrate (817).

d-Galactose.

Active transport of d-galactose occurs mostly through two inducible systems with different K_ms: one in the range of 5 μM, and the other in the range of 0.5 μM (Fig. 2) (362, 363, 634, 742, 909). The low-affinity transport system, or d-galactose permease, is driven by proton motive force and is not associated with a periplasmic binding protein (179, 336, 430). The permease (a 37,000-Da integral membrane protein) is encoded by galP at min 64 (540, 709). Expression of the gene is under the control of the repressor encoded by galR at min 61.5 (128, 908), the same repressor that controls the expression of the galETK operon (see below).

The high-affinity transport system is more complex and is referred to as the β-methylgalactoside (an excellent substrate), or mgl, system (97, 738, 739). It includes a periplasmic binding protein with high substrate affinity, which also plays an important role in the effective recapture of endogenous d-galactose leaking out of the cytoplasm (37, 38, 39, 86, 939). The binding protein attracted even greater interest when it was found to be the signal receptor for chemotaxis (331, 417, 418, 792, 954). This protein, the function of which depends on substrate-induced conformational change, is a polypeptide of 309 amino acids (87, 91, 92, 541, 561). Its three-dimensional structure was established by X-ray diffraction (883). Like other transport mechanisms dependent on a periplasmic protein, the mgl system seems to operate directly at the expense of a high-energy phosphate (88, 179, 336, 653, 882; see also chapter 76). It may be noted that β-methylgalactoside can serve as a sole source of carbon and energy, since the compound is able to induce the lac system. The induced β-galactoside permease serves as an auxiliary (low-affinity) transport system for β-methylgalactoside, and β-galactosidase hydrolyzes the compound to liberate d-galactose, which in turn induces the mgl system (715; B. Rotman, personal communication). At high substrate concentrations, the low-affinity galP permease and the high-affinity mgl permease appear to interact in such a way that most of the flow is directed through the galP permease (908).

Proteins of the high-affinity transport system are specified by the mgl gene cluster (min 45) with three identified complementation groups: mglB encoding the periplasmic binding protein, mglA encoding the integral inner membrane protein of 52,000 Da, and mglC encoding a protein of 38,000 Da apparently loosely associated with the inner membrane. The three genes apparently belong to a single operon, mglBAC, with counterclockwise transcription (94, 96, 318, 633, 634, 714, 740, 741). The following three genes have been implicated in regulating mglBAC expression: mglD, located on the clockwise side of the structural genes, which appears to code for a specific repressor of 19,000 Da (713, 740; B. Rotman, personal communication); mglR, closely linked to galK at min 17 (268); and a second mglR, situated between min 56 and 74 (504). Mutations in all three genes can lead to constitutive expression of mglBAC. It is possible that products of the two unlinked genes influence mglBAC expression indirectly; e.g., a deficiency of one of the products may cause internal induction.

Once inside the cytoplasm, d-galactose is metabolized by reactions mediated sequentially by galactose kinase, galactose-1-phosphate uridyl transferase, and UDP-galactose 4-epimerase (415, 461, 462, 800, 910). The net result of the three reactions is the conversion of d-galactose to glucose 1-phosphate. The catalytic amount of UDP-glucose required is supplied by another reaction mediated by UDP-glucose pyrophosphorylase. Most of the mutations affecting d-galactose utilization were noted to be clustered at a locus close to the prophage lambda before the exact nature of the association of the viral genome with the host genome was discovered (482, 578, 579). This cluster included the genes for the kinase, the transferase, and the epimerase (13, 481, 577, 820). These genes belong to the galETK operon at min 17 (10, 10a, 124, 125, 126, 128, 198, 345, 542, 596, 597, 795a, 851). The operon is unusual in two respects. First, it has two overlapping promoters; the cAMP-CRP complex stimulates transcription from the upstream one and inhibits that of the downstream one. Second, there are two operators, one of which is within the structural gene galE (19, 376, 377, 542). Transcription is under the negative control of a repressor encoded by galR at min 61.5, and d-galactose is the true inducer (9, 127, 376, 748, 881). Despite the fact that the structural genes are members of the same operon, synthesis of the enzymes is not always coordinate. There is a relatively high basal level of the epimerase which is necessary for d-galactose biosynthesis when the cells are growing on other carbon sources. It is conceivable that the promoter which is inhibited by cAMP initiates the transcript favoring the synthesis of the epimerase. The rate of basal synthesis of the enzymes programmed by the gal operon is determined by the delicate balance between the rate of liberation of free d-galactose from UDP-galactose, the rate of the escape of the sugar from the cytoplasm, the rate of the recapture of the sugar by the high-affinity transport system, and the rate of phosphorylation by the kinase (405, 419, 793a, 938, 940, 941). Early reports that expression of the gal operon is also under repressive control of the lon (capR) gene product were not confirmed (860).

Mutants lacking the kinase fail to grow on d-galactose, but growth on other sources of carbon and energy is not inhibited by the sugar. Such mutants also express the remaining enzymes of the d-galactose pathway (including the β-methylgalactoside permease) constitutively. Mutants lacking the transferase are arrested in their growth by d-galactose, which can cause the accumulation of galactose 1-phosphate to a level of 2 mM. For reasons still unknown, this growth inhibition can be overcome by the addition of yeast extract or casein digest to the culture medium, without reducing the galactose 1-phosphate level in the cells. Glucose is also protective and can reverse the inhibition even 1 h after exposure to d-galactose. (It is now clear that the effect is related to exclusion of d-galactose by glucose; see chapter 75.) Genetic loss of the epimerase, in contrast, has drastic consequences. Exposure of growing cells to d-galactose results in the accumulation of UDP-galactose and galactose 1-phosphate, terminating in bacteriolysis. When grown in the absence of d-galactose, the lipopolysaccharides of the mutant are deficient in this sugar component, since there is no method for its biosynthesis. As a consequence, they become susceptible to attack by phage C-21 (406, 416, 419, 463, 945).

Although the main role of UDP-glucose pyrophosphorylase is the biosynthesis of polysaccharide moieties in the cell wall, deficiency in the activity of this enzyme also prevents growth on d-galactose and renders the cell sensitive to d-galactose inhibition during growth on other carbon and energy sources (836). The enzyme is encoded by galU at min 27.2 and is under repressor control (117, 795). When mutants lacking this enzyme are infected by T-even phages, the DNA of their progeny is deficient in the glucosylation of hydroxymethylcytosine. The DNA of such viral crops is thus rendered vulnerable to restriction by certain bacterial hosts in the next round of infection (324, 798). On the other hand, because of the alteration in their cell surface, galU mutants (like galE mutants) are more resistant to P1 infection (261).

S. typhimurium

d-Mannose.

The enzyme II^Man of broad specificity also acts on N-acetylglucosamine and glucosamine (702). Curiously, growth on d-mannose decreases the activity level of phosphomannose isomerase. Yet mutational loss of this enzyme prevents growth on the sugar. However, growth of the mutant on other carbon sources is not inhibited by d-mannose; this is unexpected because accumulation of phosphorylated carbohydrates is generally deleterious to the cell. As anticipated, the isomerase mutants make imperfect wall lipopolysaccharides when grown in the absence of d-mannose. Indeed, they can be selected for their resistance to phage P22 because the altered cell surface makes adsorption difficult (733).

d-Galactose.

The low-affinity proton-motive-force-driven permease, encoded by galP which is controlled by the galR gene product, serves as the principal transport system for d-galactose, since the sugar fails to induce the mgl system in wild-type cells (600, 749, 873). The mgl system does serve for growth on β-methylgalactoside and is encoded by the mglBAEC operon, as follows. The B gene encodes a periplasmic binding protein of 33,000 Da, the A gene encodes a membrane protein of 51,000 Da, the E gene encodes a less well-characterized protein of 21,000 Da, and the C gene encodes a membrane protein of 29,000 Da (24, 570, 583, 584, 585, 954).

d-Galactose-induced cell lysis was first observed in pleiotropic mutants of Salmonella species. The sugar induces no lysis in a glucose-containing medium or under conditions not permitting growth. If growth is allowed to take place in a hypertonic medium, protoplasts are formed (262). These mutants were later discovered to lack the epimerase; their exposure to galactose led to the accumulation of UDP-galactose and galactose 1-phosphate. The envelopes of these mutants contain only glucose and lack the usual components of galactose, mannose, rhamnose, and abequose. Among the consequences of the anomalous wall structure is the interference with the adsorption of phages such as P22 (263, 264, 265, 610, 638, 811). The positions of the gal genes correspond approximately to those of their counterparts in E. coli; galK, galT, and galE constitute an operon at min 18, galU constitutes one at min 34, and galR constitutes one at min 62 (224, 266, 611, 758). Although E. coli is known to have only a single form of UDP-glucose pyrophosphorylase, S. typhimurium has three forms of this enzyme, each with distinct kinetic properties. It is believed that the protein specified by galU is subsequently modified by the product of galF (min 42). This process would explain why a mutation in galU can abolish all three activities (260, 601, 602, 603).

THE AMINO SUGARS: E. COLI

Each of the amino sugars N-acetyl-d-glucosamine and d-glucosamine can enter the cell by at least two pathways initiated by the PTS (Fig. 5). N-Acetyl-d-glucosamine is phosphorylated by a specific enzyme II (encoded by nagE or ptsN at min 15.6) of its own and by the major enzyme II for d-glucose (ptsG product), although N-acetylglucosamine cannot induce the latter enzyme. d-Glucosamine is phosphorylated by the enzyme II for d-glucose and the enzyme II for d-mannose. Since both of these systems act on d-glucose, it is not surprising that this sugar powerfully inhibits the uptake of d-glucosamine (402, 502, 899, 900). In addition to serving as a general source of carbon and energy, the amino sugars contribute directly to the synthesis of peptidoglycan and lipopolysaccharides (200). The two pathways converge when N-acetylglucosamine 6-phosphate is converted by a deacetylase to give glucosamine 6-phosphate (898), which in turn is converted by a deaminase to yield fructose 6-phosphate (161, 275, 928, 929, 930; M. Soodak, Bacteriol. Proc., p. 131, 1955). In vitro, it was found that the deacetylase was inhibited by glucosamine 6-phosphate and that the deaminase was stimulated by N-acetylglucosamine 6-phosphate (162, 901). It would be worthwhile to test whether these kinetic properties are also of physiological significance. The deacetylase is inducible by N-acetyl-d-glucosamine but not by d-glucosamine, whereas the deaminase is inducible by both carbon sources. N-Acetyl-d-glucosamine is more effective than d-glucosamine in repressing glucosamine-6-phosphate synthetase (l-glutamine:d-fructose-6-phosphate aminotransferase), the activity of which is necessary for the biosynthesis of macromolecules of the cell envelope during growth on other carbon sources. The nagA gene encoding the deacetylase and the nagB gene encoding the deaminase are 98% linked by transduction and map at min 15.6 (361). Mutants lacking the deacetylase lyse in the presence of N-acetyl-d-glucosamine in the medium, whereas the growth of mutants lacking the deaminase is inhibited by either N-acetyl-d-glucosamine or d-glucosamine. The deleterious effect of N-acetylglucosamine can be overcome by addition of uridine (73, 737, 898). It may be noted that mutants lacking glucosamine-6-phosphate synthetase require N-acetyl-d-glucosamine or d-glucosamine for growth; deprivation causes rapid loss of viability which is not preventable by sucrose as an osmotic stabilizer (374, 761, 937).

Fig. 5Metabolic pathways of N-acetylglucosamine and D-glucosamine.

Source:

METHYLPENTOSES

E. coli

l-Fucose.

The pathway for the utilization of l-fucose (Fig. 6) is mediated sequentially by l-fucose permease (291), l-fucose isomerase (282), l-fuculose kinase (210, 272, 333), and l-fuculose-1-phosphate aldolase (271, 273). The aldolase cleaves the C₆ substrate to dihydroxyacetone-phosphate and l-lactaldehyde. Anaerobically, l-lactaldehyde is completely reduced to l-1,2-propanediol by an NAD-linked oxidoreductase. For each mole of fucose fermented, 1 mol of l-1,2-propanediol is excreted and irretrievably lost (152, 824). There is suggestive evidence that the product crosses the plasma membrane by facilitated diffusion (290, 943). The sacrifice of one-half of the carbon skeleton of l-fucose in this way permits more dihydroxyacetone-phosphate to be assimilated as a carbon source. Aerobically, l-lactaldehyde is completely oxidized by an NAD-linked dehydrogenase to l-lactate, which is converted to pyruvate by a dehydrogenase (inducible by l-lactate) of the flavoprotein class (134, 152, 823).

Fig. 6Catabolic pathways for methylpentoses.

Source:

The genes specifying l-fucose utilization are all clustered at min 60.5 in clockwise order: fucO for the propanediol oxidoreductase, fucA for the aldolase, fucP for the permease, fucI for the isomerase, fucK for the kinase, and fucR for the activator protein (48, 138, 519, 815, 816). l-Fuculose 1-phosphate is the inducer (J. M. Bartkus and R. P. Mortlock, Abstr. Annu. Meet. Am. Soc. Microbiol. 1983, K238, p. 216). Although the fucO gene is induced both aerobically and anaerobically, fully catalytically active oxidoreductase is synthesized only anaerobically (100, 141, 142). Because of the lack of activity of the aerobically synthesized fucO product and because of the failure of l-1,2-propanediol to induce the necessary enzymes, wild-type E. coli cannot salvage the excretion product in the presence of molecular oxygen. However, repeated aerobic selection on l-1,2-propanediol eventually gives rise to mutants that constitutively express an altered fucO. In such mutants, fucPIK becomes noninducible, and fucA becomes constitutive. The enzyme patterns of the various mutants thus indicate that the fuc system is a regulon containing at least three operons: fucO, fucA, and fucPIK (99, 140, 291, 292, 824). From an l-1,2-propanediol-positive strain, a mutant that uses the constitutive oxidoreductase for growth on xylitol was isolated (942). That same l-1,2-propanediol-positive strain also gave rise to mutants able to grow on ethylene glycol (Fig. 7) by successive involvement of the constitutive oxidoreductase, l-lactaldehyde dehydrogenase, and enzymes of the glycolate pathway (101, 134, 635).

Fig. 7Catabolic pathway for ethylene glycol.

Source:

l-Rhamnose.

About three-fourths of the E. coli strains examined grew on l-rhamnose (212). In parallel with the pathway for l-fucose, the utilization of l-rhamnose (Fig. 6) involves the sequential action of a permease (J. Power, personal communication, 1966), an isomerase (843, 911), a kinase (145, 844, 912), and an aldolase (144, 146, 147, 762, 788). The products are dihydroxyacetone-phosphate and l-lactaldehyde. The rha system itself, however, does not include a gene for l-1,2-propanediol oxidoreductase. Growth on l-rhamnose induces the enzyme encoded by fucO (98, 143). The report of an l-1,2-propanediol oxidoreductase in a mutant with an extensive deletion covering the fuc region (731) has not been confirmed. The genes rhaD (encoding the aldolase), rhaA (encoding the isomerase), rhaB (encoding the kinase), rhaC (encoding the activator protein), and rhaP (encoding the permease) are clustered at min 87.7 in clockwise order (643, 679; J. Power, personal communication, 1966). There might be a periplasmic binding protein associated with the rha system, since l-rhamnose, in contrast to l-fucose, is chemotactic (12).

S. typhimurium

A fuc system probably similar to that of E. coli is responsible for growth of S. typhimurium on l-fucose (629). The growth abilities of different strains on l-rhamnose vary. l-Rhamnose-positive mutants were isolated from strains without the growth ability (20, 207, 221, 576). Strain LT2 grows on the sugar; its genes for l-rhamnose utilization are clustered in the order rhaD-rhaA-rhaB-rhaC-rhaT (or rhaP) at min 86.5 (30, 758). Anaerobic growth on the sugar is associated with equimolar excretion of l-1,2-propanediol (52).

PENTOSES AND TRIOSES

E. coli K-12

l-Arabinose.

The pathway for l-arabinose utilization collects the substrate from two inducible systems of transport (Fig. 8). The low-affinity permease (K_m, about 0.1 mM) is encoded by araE at min 61.3 (223, 620). The high-affinity system (K_m, 1 to 3 μM) is specified by the araFG operon at min 44.8. The araF gene encodes a periplasmic binding protein (306 amino acids) with chemotactic receptor function (114, 148, 259, 276, 357, 358, 359, 550, 551, 552, 607, 608, 654, 655, 686, 688, 772, 792), and the araG locus encodes at least one inner membrane protein (149, 438, 453). Both high- and low-affinity transport are under the control of the araC gene product and are thus part of the ara regulon (223, 437). The araE system is energized by proton motive force, whereas the araF system seems to operate at the expense of a high-energy covalent bond (179, 539).

Fig. 8Catabolic pathways for pentoses and pentitols.

Source:

Internally, the sugar is metabolized by a set of enzymes encoded by the araBAD operon at min 1.4: an isomerase which reversibly converts the aldose to l-ribulose; a kinase which phosphorylates the ketose to l-ribulose 5-phosphate; and l-ribulose-5-phosphate-4-epimerase, which catalyzes the formation of d-xylose 5-phosphate (104, 219, 222, 491, 492). The genes are transcribed in counterclockwise order: B (encoding the kinase), A (encoding the isomerase), and D (encoding the epimerase). Expression of the operon is under the specific control of the product of araC on the clockwise side of araBAD. The two operons are divergently transcribed. Whereas araC is autogenously repressed by the regulator protein in the presence or absence of the inducer l-arabinose, araBAD is activated by the regulator protein-inducer complex and repressed by the regulator protein alone. Expression of both operons is dependent on the cAMP-CRP binding site (493, 625). Growth of isomerase or kinase mutants on casein hydrolysate is inhibited by the addition of l-arabinose. In the case of the kinase mutant, l-ribulose accumulates in the culture. Growth of epimerase mutants is severely inhibited by l-arabinose, and the accumulated l-ribulose 5-phosphate can attain a concentration of 5 mM (calculation based on 2.7 ml of cell water per g [dry weight] according to Maloney et al. [544]). The growth inhibition is prevented or relieved by the addition of glucose but not by the addition of d-fructose or d-mannose (106, 220, 286). In contrast to E. coli K-12, E. coli B requires a mutation before it can grow on l-arabinose (155).

d-Arabinose.

Most strains of E. coli are incapable of growing on d-arabinose. Since the enzymes of the l-fucose pathway have side specificities to convert d-arabinose to dihydroxyacetone phosphate and glycoaldehyde (105, 158, 271, 282, 333, 477, 479), all that is required for the additional growth ability is a mutation rendering the fuc system inducible by d-arabinose (478, 815, 816). An interesting exception is E. coli B/r, which does not grow on l-fucose but does grow on d-arabinose. This organism lacks l-fuculose-1-phosphate aldolase. The d-ribulose arising from d-arabinose is phosphorylated to d-ribulose 5-phosphate, which is isomerized to d-xylulose 5-phosphate (104).

d-Xylose.

Most strains of E. coli grow on d-xylose, but a mutation is necessary for strain K-12 to grow on the compound (31, 118, 212). Utilization of this pentose is through an inducible and catabolite-repressible pathway (Fig. 8) involving transport across the cytoplasmic membrane (not active on d-ribose or d-arabinose), isomerization to d-xylose, and ATP-dependent phosphorylation of the pentulose to yield d-xylulose 5-phosphate (183). As in the case of d-galactose and l-arabinose utilization, d-xylose can enter through two inducible permeases. The high-affinity (K_m, 0.3 to 3 μM) system depends on a periplasmic binding protein (37,000 Da) and is probably driven by a high-energy compound. The low-affinity (K_m, about 170 μM) system is energized by proton motive force. This d-xylose-proton-symport system is encoded by xylE at min 91.4 (14, 184, 473, 793). The main gene cluster specifying d-xylose utilization, xylAB(RT), is at min 79.7. The nucleotide sequence of the region has been determined. The genes xylA (encoding the isomerase, 54,000 Da) and xylB (encoding the kinase, 52,000 Da) belong to an operon with a second transcriptional start preceding the coding region of xylB. It is believed, based partly on studies of S. typhimurium, that xylR encodes a regulator protein of 10,000 Da and that xylT encodes a transport protein of 16,000 Da (56, 476, 543, 736, 771, 852, 936). Since the low-affinity permease is specified by the unlinked xylE, the xylT locus probably codes for the high-affinity transport system and therefore should contain at least two genes (one for a periplasmic protein and one for an integral membrane protein). Further work is required to identify these two genes and the effect of the regulator protein.

d-Xylose System for Growth on Novel Substrates.

Constitutive expression of the d-xylose pathway permits growth on xylitol if the cells also constitutively synthesize a catalytically active l-1,2-propanediol oxidoreductase under aerobic conditions (see Methylpentoses, above). Xylitol is transported by a d-xylose permease and is then converted by the l-1,2-propanediol oxidoreductase to d-xylose (942). A mutant which acquired the ability to grow on d-lyxose also uses a d-xylose permease (inducible) for transport. d-Lyxose is then converted to d-xylulose by an isomerase (active also on d-mannose) determined by the locus mni in the region of min 86. The gene is apparently cryptic in the wild-type parent (826). d-Xylulose kinase contributes to a novel pathway for d-arabitol in a mutant that converts the pentitol to d-xylulose by an NAD-linked dehydrogenase (active also on d-galactose) which became constitutive (943).

d-Ribose.

At least two transport systems mediate the entry of d-ribose into the cytoplasm (Fig. 8); the one with low affinity is apparently constitutive, and the one with high affinity is inducible. High-affinity transport (K_m of uptake, about 1 μM) is dependent upon a periplasmic binding protein that serves also as a receptor for chemotaxis (267, 270, 331, 906, 907). The d-ribose-binding protein shows substantial amino acid sequence homology with the d-galactose-binding protein, in contrast to the lack of homology between the d-galactose- and l-arabinose-binding proteins (42, 285). The conservation of amino acid sequence between the d-ribose- and the d-galactose-binding proteins is believed to be the consequence of their having to interact with a common signalling component in the plasma membrane (see chapter 10). Transport by the high-affinity system appears to be driven by high-energy bonds (173).

Internal d-ribose is phosphorylated by an inducible kinase that catalyzes the formation of d-ribose 5-phosphate and is feedback inhibitable by the product (180, 181, 182, 213, 332, 533). This pathway is specified by the rbsACBK operon located at min 84.3 and is transcribed clockwise, as follows: rbsA encodes a 50,000-Da protein required for high-affinity transport, rbsC encodes a 27,000-Da protein presumed to be a transport protein association with the inner membrane, rbsB encodes the 29,000-Da binding protein, and rbsK encodes a 34,000-Da kinase. Expression of the operon is under the control of a repressor encoded by the rbsR gene, which is on the clockwise side of the structural genes and which is apparently transcribed independently. Ribose, rather than d-ribose 5-phosphate, which is an intermediate of the pentose phosphate cycle, is the true inducer. The location and true physiological role of the gene(s) specifying the low-affinity d-ribose transport (in the 10 mM range) are not known, except that cAMP is not required for gene expression (31, 32, 372, 535, 878, 879).

E. coli B, which is d-ribose negative (155), has two nonfunctional rbs operons (which perhaps arose by duplication and transposition). The one at min 84 has intact structural genes which are not expressible; the one at min 2 is constitutively expressed but has a defective rbsK. d-Ribose-positive revertants can arise by either a mutation that allows the inducible expression of the min 84 operon or a mutation that restores the kinase gene of the min 2 operon. Expression of the rbs operons, in contrast to the K-12 system, seems to be under positive control (1, 2, 3, 4, 5, 6).

Trioses.

There exists a specific inducible enzyme II for dihydroxyacetone (394). It is not known whether d-glyceraldehyde can be similarly utilized.

S. typhimurium

l-Arabinose.

Kinetic studies indicate that there is only a low-affinity permease for l-arabinose uptake. A permease protein of 40,000 Da is encoded by araE at min 62, and transcription is counterclockwise (487, 490, 747a). However, a binding protein was isolated, and its sequence was found to be highly similar to that of the araF protein of E. coli (360). The metabolic pathway, as well as the regulatory mechanisms for gene expression, seem to be similar to the system in E. coli (76, 77, 78). The ara genes encoding the enzymes in the pathway map at min 2.7 (139, 429). Mutants lacking the epimerase are sensitive to l-arabinose (488, 684, 685, 747). The araBAD and araC operons of S. typhimurium resemble those of E. coli. The structural genes are transcribed counterclockwise, and the regulator gene is transcribed clockwise (150, 283, 365, 489).

d-Arabinose.

Mutants that acquire the ability to grow on d-arabinose exhibit dual inducibility of the l-fucose pathway (629).

d-Xylose.

Although kinetic studies suggested the presence of only one low-affinity transport system (K_m, 0.4 mM) indicative of a proton-motive-force-driven mechanism, a d-xylose-binding protein, expected to be associated with a high-affinity transport system and driven by a high-energy phosphate compound, was detected. Expression of the inducible pathway is subject to catabolite repression, which can be reversed by the addition of cAMP (793). The possibility that the high-affinity transport system in S. typhimurium is impaired by a mutation in one of its structural genes deserves examination. The genes for d-xylose utilization cluster at min 78 in clockwise order: xylT (encoding a permease)-xylR (encoding the activator protein)-xylB (encoding the kinase)-xylA (encoding the isomerase). The trans-activating effect of the xylR product was demonstrated by merodiploid analysis (274, 794). Limiting permease activity accounts for the defective abilities of some strains of S. typhimurium to utilize d-xylose (581, 630).

d-Ribose.

A d-ribose-binding protein, serving as a component for substrate transport and a receptor for chemotaxis, shares a signalling component with the d-galactose-binding protein (21, 22, 582, 833).

2-Deoxy-d-Ribose.

2-Deoxy-d-ribose supports growth of strain LT2 (288). (For a further description of the metabolic and genetic system, see Pentoses in Nucleosides and Deoxynucleosides, below.)

Trioses.

The growth of strain LT2 on dihydroxyacetone (288) presumably depends on an inducible enzyme II^Dha, as in E. coli K-12.

PENTOSES IN NUCLEOSIDES AND DEOXYNUCLEOSIDES

E. coli

An early observation that E. coli utilized the d-ribose moiety of adenosine faster than it did the free pentose implied that the nucleoside was taken up by the cell directly (825). Later studies revealed that the cell can utilize a number of purine and pyrimidine nucleosides and deoxynucleosides as sole source of carbon and energy. Movement of these compounds (except cytidine and deoxycytidine) across the outer membrane is facilitated by the product of the tsx gene (min 9.4). An aqueous pore seems to be provided by the protein (25,000 Da) which is also exploited by phage T6 and colicin K as receptors (317, 547, 562, 591). Synthesis of the outer membrane protein is under multiple regulation by the cAMP-CRP complex, the cytR repressor, and the deoR repressor. These regulatory proteins also control the expression of the genes for the further metabolism of the substrates (455, 457). At least three transport systems are involved in the uptake of the compounds into the cytoplasm (591, 657, 658). A model requiring phosphorolytic cleavage of the nucleosides during translocation was proposed (346, 347, 692) but was not substantiated (123, 642). Instead, transport of nucleosides was shown to precede their enzymatic attack (514, 587). Two major concentrating systems have been well characterized by analysis of mutants. The C system (encoded by nupC at min 52), first revealed by its activity on the antibiotic showdomycin [2-(β-d-ribofuranosyl)maleimide] which is a nucleoside analog capable of alkylating sulfhydryl groups, transports cytidine and other ribonucleosides and deoxyribonucleosides (except those of guanine and hypoxanthine). The G system (encoded by nupG at min 64) has a broad specificity with preference for the guanine compounds (203, 204, 439, 440, 443, 444, 591, 592, 743, 744, 745, 875, 876). Both systems appear to be driven by proton motive force. In the case of the G system, the lowering of the ATP pool increases the rate of nucleoside transport activity. This inverse relationship would indicate the existence of a kinetic feedback mechanism (445, 594, 746). Synthesis of the C system is regulated by the cytR repressor and the cAMP-CRP complex, whereas synthesis of the G system is under the double control of the cytR and deoR products as well as the cAMP-CRP complex (202, 590, 599). A third transport system was found to act on nucleosides of adenine, guanine, and hypoxanthine (441, 442).

The catabolic pathways for the nucleosides might be viewed as a way of extracting from them the pentose or deoxypentose for use as carbon and energy sources. This purpose is achieved by the combined action of eight inducible enzymes that catalyze the following reactions, in which P is phosphate:

Deamination is not needed for the utilization of all of the nucleosides, and cleavage of the pentose is only needed for the further utilization of 2-deoxy-d-ribose. The utilization of cytidine and deoxycytidine requires their conversion to uridine and deoxyuridine, respectively, by a specific deaminase of about 54,000 Da encoded by cdd (transcribed clockwise at min 45), as shown in equation 1 (153, 154, 157, 159, 366, 408, 409, 420, 593, 890). For adenosine and deoxyadenosine utilization, deamination by an inducible enzyme encoded by add (min 36), as shown in equation 2, may occur before phosphorolysis (397, 420, 435, 548, 624, 701).

Phosphorolysis of uridine liberates its uracil moiety with the formation of the ribose 1-phosphate, as shown in equation 3. Reactions of this kind are reversible. Indeed, at neutral pH the synthesis of nucleosides is favored, irrespective of whether the base is a pyrimidine or a purine (103, 652). The specific phosphorylase comprises eight subunits of 22,000 Da encoded by udp at min 85.5 (454, 495, 641, 683). Both cdd and udp are controlled by cAMP-CRP and by a repressor (37,000 Da) specified by cytR at min 76.5 and responding to cytidine or adenosine as inducers (312, 313, 315, 593, 813, 872).

Another phosphorylase (a dimer of a 100,000-Da subunit) acts on xanthosine, as shown in equation 4. The enzyme is encoded by xapA (close to nupC at min 52), which is activated by the closely linked xapR product with xanthosine as the probable inducer. A class of xapR mutants was isolated for which adenosine, deoxyadenosine, and inosine (but not guanosine or deoxyguanosine) also became inducers (133, 310).

Catabolism of thymidine and purine ribonucleosides and deoxyribonucleosides also begins with the release of their pentose moieties by phosphorolysis (549). The reactions catalyzed by thymidine phosphorylase (353) and purine phosphorylase (373, 434, 639) are shown by equations 5 and 6, respectively. Thymidine phosphorylase (a dimer of an approximately 45,000-Da subunit) is highly specific for deoxyribose 1-phosphate (111, 689, 697, 698, 783, 785). However, the enzyme can be inhibited by uridine (119). Purine nucleoside phosphorylase (a hexamer of 23,700-dalton subunits), in contrast, has a broad substrate specificity that includes the ability to cleave both the ribonucleosides and the deoxyribonucleosides of adenine, guanine, and hypoxanthine (205, 389, 390, 420). Transfer of the phosphoryl group of both deoxyribose 1-phosphate and ribose 1-phosphate to C-5 is catalyzed by a single mutase, as indicated in equation 7 (353). The activity of the enzyme (45,000 Da) is dependent on Mn²⁺ and is stimulated about 10-fold by ribose 1,5-biphosphate or deoxyribose 1,5-biphosphate (311, 494). Ribose 5-phosphate is further metabolized by the nonoxidative pentose phosphate pathway; deoxyribose 5-phosphate, as indicated in equation 8, is converted to glyceraldehyde 3-phosphate and acetaldehyde by a class I deoxyriboaldolase (capable of forming a Schiff’s base) active as a monomer or dimer of a polypeptide of 259 amino acids (690, 691, 869). Free 2-deoxy-d-ribose was reported to be utilized by a kinase that acts on C-5 of the sugar (403, 404), but this was not confirmed (352, 587). The enzymes for nucleoside catabolism appear to be intimately associated with the inner surface of the plasma membrane in that they are readily, though only partially, released from the cells by osmotic shock but nonetheless were well retained by spheroplasts (62, 642, 845).

Wild-type cells grow on cytidine, uridine, adenosine, inosine, guanosine, xanthosine, deoxycytidine, deoxyuridine, thymidine, deoxyadenosine, deoxyinosine, and deoxyguanosine. Growth phenotypes of mutants, with the exception of growth phenotypes on adenosine and deoxyadenosine, are predictable on the basis of the eight reactions outlined in the equations above.

Mutants lacking cytidine deaminase fail to grow on cytidine or deoxycytidine (equation 1). Growth of mutants lacking adenosine deaminase is inhibited by adenosine or deoxyadenosine (the activity of purine nucleoside phosphorylase is apparently inadequate) (equation 2). Mutants lacking uridine phosphorylase fail to grow on cytidine and uridine (equation 3). Mutants lacking xanthosine phosphorylase fail to grow only on the particular substrate (equation 4). Mutants lacking thymidine phosphorylase fail to grow on deoxycytidine, deoxyuridine, and thymidine (equation 5). Interestingly, the absence of thymidine phosphorylase could be genetically suppressed by a 30- to 45-fold increase in the level of uridine phosphorylase activity (834). Mutants lacking purine ribonucleoside phosphorylase fail to grow on the ribosides and deoxyribosides of adenine, hypoxanthine, and guanine (equation 6). Mutants lacking the mutase fail to grow on all 12 ribonucleosides and deoxyribonucleosides mentioned (equation 7). Mutants lacking the aldolase (equation 8) fail to grow on only the deoxynucleosides (15, 232, 309, 314). Aldolase mutants are, in addition, sensitive to deoxyribonucleosides as a result of deoxyribose 5-phosphate accumulation. The inhibition of growth by thymidine can be released after the exhaustion of the exogenous supply and the excretion of 2- deoxy-d-ribose and thymine into the medium (28, 215, 532, 588, 589). The absence of the aldolase or mutase activity lowers the concentration of thymine required by thymineless strains, since trapping the free base depends on deoxyribose 1-phosphate, which would be depleted by the activity of these enzymes (112, 319, 626; A. Munch-Petersen, personal communication).

The deoA gene (deoxynucleoside) encoding thymidine phosphorylase, the deoD gene encoding purine nucleoside phosphorylase, the deoB gene encoding the mutase, and the deoC gene encoding the aldolase are clustered at min 99.5 (15, 16, 177, 953). A regulator gene, deoR at min 18.7, codes for a 30,500-Da repressor which is inactivated by deoxyribose 5-phosphate (55, 113, 532, 593, 813). Effects of polar mutations and discoordinate control of the synthesis of the enzymes suggested that the four enzymes are specified by two operons (17, 18, 58, 83, 129, 587). Further studies, however, revealed that the complex pattern of gene expression reflects the interactions of three specific regulator gene products with three promoters (all transcribed clockwise) of the gene cluster (Fig. 9). The first promoter region, deoOP, contains a site for the deoR repressor and is independent of the cAMP-CRP complex for expression. Transcription from the nearby second promoter, cytOP, is influenced by the deoR repressor, the cytR repressor, and the cAMP-CRP complex. There are two tandem CRP-binding sites; the one upstream seems to overlap with the binding site for the cytR repressor. The lack of either the deoR repressor (inactivated by deoxyribose 5-phosphate) or the cytR repressor (inactivated by cytidine or adenosine) leads to increased basal expression of the entire deo operon; a double regulatory defect leads to constitutive expression of the operon to a level higher than the sum of the effects of single mutations (25, 130, 178, 244, 313, 593, 805, 837, 838, 867, 868, 872). Transcripts from deoOP and cytOP are tetracistronic. A third promoter, between deoA and deoB, gives dicistronic transcripts. Although the regulatory gene product controlling this transcription has not yet been identified, induction was observed with inosine or guanosine, neither of which requires expression of deoC and deoA for utilization (26, 131, 132, 407, 870, 871).

Fig. 9Interactions of three specific regulator gene products with three promoters of the deoA-deoB-deoC-deoD gene cluster.

Source:

S. typhimurium

Uridine (not an inducer in E. coli) or cytidine induces cytidine deaminase (encoded by cdd at min 44), uridine phosphorylase (encoded by udp at min 84), and the enzymes of the deo operon (64, 65, 384, 606, 623). Based on what is known, the organization of the deo operon is similar to that of E. coli; deoC encodes the deoxyriboaldolase (165, 350, 388), deoA encodes thymidine phosphorylase (82, 351), deoB encodes phosphodeoxyribomutase (352), and deoD encodes purine nucleoside phosphorylase (348, 354, 389, 390, 724), all of which are clustered at min 98.8 and are transcribed clockwise. A second promoter exists between deoA and deoB. The regulatory gene, deoR (min 19 to 20), responds to deoxyribose 5-phosphate as an inducer (61, 81, 269, 352, 386, 387, 725).

Exogenous 2-deoxy-d-ribose supports growth through an inducible pathway involving a permease encoded by deoP (min 19 to 20) and an ATP-dependent kinase encoded by deoK (min 19 to 20) (349, 758). On the basis of locality, it seems that deoP and deoK are also under the control of deoR. Complex regulatory interactions of the nucleoside and deoxynucleoside pathways with the central glycolytic pathway are suggested by the observation that, among mutants selected for failure to grow on thymidine, 37% were found to have reduced expression of the deo operon associated with deficient fructose-1,6-bisphosphatase activity (385). Unlike E. coli, S. typhimurium lacks xanthosine phosphorylase (310).

HEXURONIDES, HEXURONATES, AND HEXONATES:

E. coli

Hexuronides, Hexuronates, and KDG.

β-Glucuronides support growth by yielding d-glucuronate through the successive action of an inducible permease (829) and a hexuronidase (Fig. 10). Although the hydrolase is also capable of acting on β-galacturonides, these compounds cannot be utilized, because they fail to induce the system. Mutants selected for growth on a β-galacturonide synthesize the hydrolase constitutively (193, 194).

Fig. 10Catabolic pathways for D-glucuronide, hexuronates, and hexanates.

Source:

External d-glucuronate can be utilized via a permease for hexuronates or via a permease for d-2-keto-3-deoxy-d-gluconate (KDG) if it is constitutive. External d-galacturonate can be utilized only via the hexuronate permease (49, 57, 156, 393, 605). A common isomerase reversibly converts d-glucuronate and d-galacturonate to d-fructuronate and d-tagaturonate, respectively (45, 47, 615, 842, 884). These products can also be supplied exogenously by distinct permeases not yet characterized (605). Separate NADH-linked enzymes reduce d-fructuronate and d-tagaturonate to d-mannonate and d-altronate, respectively (45, 344, 661, 664, 665), and separate enzymes catalyze the dehydration of d-mannonate and d-altronate to yield KDG (45, 672, 716, 719, 720, 818). The high substrate specificity of the two dehydratases in vivo was shown by the observation that in a mutant blocked in the cleavage of KDG 6-phosphate the growth stasis caused by d-glucuronate is relieved by a mutation that inactivates d-mannonate dehydratase, whereas the growth stasis caused by d-galacturonate is relieved by a mutation that inactivates d-altronate dehydratase (663, 722).

Exogenous KDG can be delivered by a permease with side specificity on d-glucuronate. The transport is apparently driven by proton motive force (466, 467, 468, 469, 470, 471). KDG is phosphorylated by an ATP-dependent kinase (45, 175, 673). The pathway then converges with the Entner-Doudoroff pathway, and KDG 6-phosphate is cleaved by a specific aldolase to glyceraldehyde 3-phosphate and pyruvate (46, 677).

The genes for the utilization of hexuronides and hexuronates (Fig. 11) were shown to involve regulons and operons controlled in a complex manner by four different repressors (830). Utilization of β-glucuronides was found to be affected by mutations in five genes. The gene uidA (gurA), encoding β-glucuronidase (transcribed counterclockwise), and the gene uidR, encoding a specific repressor, are at min 35.8 in clockwise order (57, 80, 613, 616, 618). The genes gurB (min 74, possibly crp), gurC (min 18), and gurD (min 68) were also found to affect hexuronide utilization, but the biochemical basis of their effect has yet to be elucidated (614). The uidA operon is strongly repressed by the uidR product and weakly repressed by the uxuR product. Full induction of β-glucuronidase appears to require the cooperative action of both d-glucuronate or a β-glucuronide to lift the repression of the uidR product and d-fructuronate to lift the repression of the uxuR product (612, 617, 619).

Fig. 11Genetic systems for the utilization of hexuronates and 2-keto-3-deoxy-D-gluconate.

Source:

The convergent metabolism of the hexuronates that terminates in the formation of KDG is specified by the exu regulon and the uxu operon. The exu regulon includes four operons: the uxaB operon (min 51) encoding d-altronate oxidoreductase; the uxaCA operon (min 67.9 and transcribed counterclockwise), with gene C encoding the isomerase and gene A encoding d-altronate dehydratase; the exuT operon (min 68 and transcribed clockwise) encoding hexuronate permease; and the exuR operon (min 68.1 and transcribed clockwise) encoding a specific repressor which autogenously represses its own synthesis. The exuR repressor has a greater affinity for the uxaB than for the uxaCA operator. d-Tagaturonate and d-fructuronate appear to be true inducers (79, 176, 369, 370, 371, 556, 557, 605, 660, 662, 663, 712, 717).

The metabolic branch converting d-fructuronate to KDG is specified by the uxu system consisting of the uxuR operon (min 97.7 and transcribed counterclockwise) encoding a specific repressor and the uxuAB operon (min 97.8 and transcribed counterclockwise), in which the A gene encodes d-mannonate dehydratase and the B gene encodes d-mannonate oxidoreductase. The uxuR operon is self repressed and catabolite repressed. The uxuAB operon is doubly repressed by the uxuR and the exuR products; both products are inactivated by d-fructuronate (379, 558, 710, 711, 717, 718, 721, 722).

KDG derived from the hexuronates or from an exogenous source is converted to glyceraldehyde 3-phosphate and pyruvate by proteins encoded by the kdg regulon under negative control. Exogenous KDG, however, can serve as the sole source of carbon and energy only if a mutation confers constitutive synthesis of the permease which is strongly repressed and only weakly inducible in strain K-12 (469, 674). The repressor gene, kdgR, is at min 40.3, the KDG-phosphate aldolase gene, kdgA (eda), is at min 40.8, the KDG kinase gene, kdgK, is at min 78.3, and the KDG permease gene, kdgT, is at min 88.1. The true inducer is KDG (229, 248, 250, 472, 545, 546, 668, 669, 674, 675, 678). The operons are differentially controlled with respect to both specific and catabolite repression. It appears that the operators of kdgA, kdgK, and kdgT have, in order, increasing affinities for the repressor. Sensitivity to catabolite repression increases in the same order. These features presumably account for both the preferential synthesis of the aldolase when d-gluconate is presented and the dual induction of the aldolase and the kinase when a hexuronate is presented. An unusual feature of catabolite repression of this system is its high sensitivity to pyruvate (469, 671, 675, 676).

When presented with d-glucuronate, d-galacturonate, or d-gluconate, growth of aldolase mutants is arrested, and they excrete KDG 6-phosphate. The stasis can be relieved with glucose (668, 670).

d-Gluconate and d-Galactonate.

A permease encoded by gntS at min 95 provides a route for the entry of d-gluconate (50). An ATP-dependent kinase converts the substrate to gluconate 6-phosphate, which then enters general metabolism via KDG 6-phosphate as well as via ribulose 5-phosphate. d-Galactonate is transported by a permease encoded by dgoT and is converted to 2-deoxy-3-keto-d-galactonate by a dehydrase encoded by dgoD. The product is then acted upon by a kinase specified by dgoK, and the phosphorylated intermediate is cleaved by an aldolase specified by dgoA to yield glyceraldehyde 3-phosphate and pyruvate. All of the genes, including the regulatory gene dgoR, cluster at min 82.5. d-Galactonate itself is the true inducer. d-Galactonate is toxic to dgoA mutants because of 2-keto-3-deoxy-d-galactonate 6-phosphate accumulation. Strain K-12 can acquire the ability to grow on 2-keto-3-deoxy-d-galactonate as a result of two mutations, one rendering the expression of the dgo system constitutive and the other mobilizing a permease encoded by an unlinked gene, odgT (164, 185).

PHOSPHORYLATED SUGARS AND CARBOXYLATES

E. coli

Hexose Phosphates.

Evidence for utilization of hexose phosphates without prior hydrolysis first came as an incidental finding that when cells were grown on hexose phosphates as carbon and energy source in the presence of inorganic phosphate they derived more nucleic acid phosphorus from hexose phosphates than from P_i (723). Studies focused directly on the problem showed that mutants impaired in the utilization of glucose grew normally on glucose 6-phosphate (251, 293). Direct-transport assays revealed the existence of an inducible permease that is active on a number of phosphorylated sugars, including glucose 6-phosphate, glucose 1-phosphate, fructose 6-phosphate, fructose 1-phosphate, mannose 6-phosphate, and glucosamine 6-phosphate (for a review, see reference 197). Analysis of mutants showed that a single permease encoded by the uhp gene located at min 82.1 is responsible for the growth abilities on hexose phosphates (451, 659, 923). Transport of the substrate is driven by proton motive force (195, 225, 693, 926). Wide-ranging K_m values (0.02 to 0.5 mM) have been reported for glucose 6-phosphate. Apparently, the values were influenced by the concentration of P_i (likely to be a competitive inhibitor) present in the assay medium (228). The permease has a side specificity for glycerol 3-phosphate (287a).

Surprisingly, the permease is induced by low concentrations of exogenous glucose 6-phosphate (<0.5 mM) but not by high concentrations of endogenous glucose 6-phosphate (up to 60 mM) generated in a mutant lacking glucose 6-phosphate dehydrogenase and phosphoglucose isomerase (196, 341, 924, 925). Since physiological concentrations of cellular glucose 6-phosphate can vary from 0.5 to 3 mM (367), the external induction mechanism prevents gratuitous production of the permease. Among the substrates tested, only glucose 6-phosphate acts as its true inducer. Although fructose 6-phosphate and mannose 6-phosphate can also support growth, it is believed that induction of the permease depends upon the generation of external glucose 6-phosphate by a periplasmic phosphoglucose isomerase (257, 923). The presence of such an enzyme outside the plasma membrane is a curious phenomenon. It is unknown whether the protein is specified by the same gene that encodes the intracellular enzyme. Full induction of the permease is dependent upon the cAMP-CRP complex (228).

Regulatory genes for this permease map close to the structural gene (226, 241, 411, 413). Fine-structure analysis revealed a cluster of at least three genes (in clockwise order) at the uhp locus: uhpT, uhpR, and uphA. The gene uhpT, encoding the permease, is transcribed counterclockwise. It was suggested that uhpA encodes a transcriptional activator and that uhpR encodes a transmembrane protein that serves as an external receptor for the inducer glucose 6-phosphate. The phenotypes of certain mutants in the uhpR region and of their revertants led to the further suggestion that there is a uhpC gene encoding a protein which masks the function of the activator protein. When the inducer binds to the transmembrane receptor, it sequesters the C protein, thereby releasing the activator protein and allowing it to function. With a mutant bearing a uhpT-lac operon fusion, it was confirmed that induction did not depend on the internal glucose 6-phosphate. External induction occurred with a K_m of about 1 μM. Furthermore, the specificity of induction is more stringent than that of transport; sugar phosphates that are substrates for transport did not inhibit induction, even when present in a 25-fold molar excess (412, 796, 797). In membrane vesicles prepared from uninduced cells, a putative receptor was found that bound glucose 6-phosphate (K_d, 16 μM) but not fructose 6-phosphate (279). It is not known whether the expression of uhpR and uhpA itself is under regulation. Growth on a hexose phosphate as sole source of carbon and energy creates a problem of phosphate excess.

sn -Glycerol 3-Phosphate.

For a discussion about sn-glycerol 3-phosphate, see Glycerol, below.

Lactate.

On the basis of mutual competition for transport into membrane vesicles, d-lactate and l-lactate were suggested to share a permease distinct from the dicarboxylate transport system (559). d-Lactate and l-lactate are both converted to pyruvate, but by separate enzymes (see chapter 17).

Dicarboxylates.

Succinate, fumarate, or l-malate induces a dicarboxylate transport system that acts on l-aspartate, in addition to the three compounds, but not on oxaloacetate (342, 424, 425, 595). Synthesis of the transport system is subject to catabolite repression. The transport process seems to be driven by proton motive force, with apparent K_m values within the range of 10 to 20 μM (289). A dicarboxylate-binding protein (dissociation constants in the 30 to 50 μM range for fumarate, malate, and succinate) is postulated to mediate substrate translocation across the outer membrane in conjunction with the porin protein (74, 75, 526, 527, 528, 529, 696). Three genes determined the transport system: dctA (encoding an inner membrane protein) at min 79.6, dctB (encoding an inner membrane protein) at about min 16.3, and cbt (encoding the binding protein) at about min 16.5. For reasons not clear, cbt (carboxylate transport) mutations also impair the transport of d-lactate (524, 525, 530, 531). Some E. coli strains were observed to utilize d-tartrate but not l-tartrate (421). The pathway has not yet been described.

Tricarboxylic Acids.

Although E. coli strains are generally citrate negative (452, 473a), a mutant of strain K-12 that grew on the compound was isolated as a consequence of mutations in citA and citB at about min 17. The ability to grow on isocitrate was acquired concomitantly. Utilization of cis- or trans-aconitate, however, required preinduction of the novel semiconstitutive transport system (302). The ability of natural isolates to grow on citrate is attributable to plasmid-encoded genes (377a, 377b, 377c, 377d, 377e, 377f).

S. typhimurium

Phosphorylated Substrates.

A hexose phosphate permease was also characterized in S. typhimurium. The transport is induced by glucose 6-phosphate and has a substrate K_m of 0.13 mM. Cells preinduced or constitutive in this permease also transported d-arabinose 5-phosphate and d-sedoheptulose 7-phosphate (214). Unlike E. coli, S. typhimurium can utilize phosphoenolpyruvate, 2-phosphoglycerate, and 3-phosphoglycerate through a common permease encoded by pgt at min 74 (288, 754).

Carboxylates.

A dicarboxylate permease was also reported for S. typhimurium (425). In contrast to E. coli, S. typhimurium can grow on citrate, isocitrate, and tricarballylate (1,2,3-propanetricarboxylate) as sole carbon and energy source (288). cis-Aconitate can probably also serve as sole carbon and energy source. Three inducible transport systems can be distinguished. The first is inducible by citrate, isocitrate, or cis-aconitase but effectively transports only citrate and isocitrate. The second is inducible by the same three compounds and transports cis-aconitate. The third is inducible by tricarballylate and transports tricarballylate, citrate, and cis-aconitate (375, 422, 423, 425a).

POLYOLS

E. coli

d-Mannitol.

Like the hexoses, d-mannitol and the other utilizable hexitols (Fig. 12) are trapped by vectorial phosphorylation (458). Moreover, the enzymes II for the hexitols also serve as receptors for chemotaxis (503). Enzyme II^Mtl is an integral membrane protein consisting of a polypeptide of 637 amino acids. The purified enzyme has a substrate K_m of 11 μM (284, 380, 381, 382, 383, 484, 485, 486, 510, 728, 729, 730). The translocation product, d-mannitol 1-phosphate, is converted by an NAD-linked enzyme dehydrogenase to d-fructose 6-phosphate, as described (932) many years before the discovery of the PTS. This dehydrogenase (apparently a monomer of a 40,000-Da polypeptide) has a K_m of 0.8 mM for the substrate and a K_m of 0.2 mM for NAD (622). The genes specifying d-mannitol utilization are at min 80.7. The mtlAD operon is transcribed in clockwise order, mtlA encoding enzyme II^Mtl and mtlD encoding the dehydrogenase. On the clockwise side of the operon lies mtlR, the repressor gene. Induction occurs with d-mannitol but not with d-glucitol or d-galactitol. Internalized d-mannitol (rather than d-mannitol 1-phosphate) seems to be the effector. The transport system acts on d-mannitol, with a K_m of 0.37 μM (and a growth K_m of 0.2 μM), and on d-glucitol, with a K_m of 2.5 mM. Thus, the constitutive expression of the mtl operon restores the ability of gutA (encoding the enzyme II^Gut) mutants to grow on d-glucitol (see below). Mutations in mtlA prevent growth on d-mannitol, whereas mutations in mtlD subject the cells to growth inhibition by the compound (499, 500, 507, 508, 521, 667, 821). Expression of the mtl operon is highly dependent upon the cAMP-CRP complex despite its strong resistance to catabolite repression (571, 946). d-Mannitol 1-phosphate is produced endogenously, even when the cells are growing on carbon sources other than d-mannitol, and contributes to the d-ribose pool through a pathway in which d-mannonate and d-2-ketogluconate are intermediates (734, 735).

Fig. 12Metabolic pathways of hexitols.

Source:

d-Glucitol (or d-Sorbitol).

Utilization of d-glucitol (Fig. 12) occurs through an inducible pathway initiated by a specific enzyme II-enzyme III complex which converts the substrate to d-glucitol 6-phosphate (505, 750). The product is then converted to d-fructose 6-phosphate by an NAD-linked dehydrogenase (a tetramer of a 26,000-Da subunit) with a substrate K_m of 3.3 mM and an NAD K_m of 0.2 mM (622, 931). The genes specifying d-glucitol utilization are at min 58.3. The gutAD (or srlAD) operon is transcribed in clockwise order, gutA encoding enzyme II(III)^Gut and gutD encoding the dehydrogenase. The gene for the repressor, gutR, lies on the clockwise side of the operon (102, 171, 172, 499, 560, 667, 905). Induction occurs with d-glucitol but not with d-mannitol or d-galactitol. Internal d-glucitol (rather than d-glucitol 6-phosphate) seems to be the effector. The operon is highly sensitive to catabolite repression by glucose. The transport system acts on d-glucitol with a K_m of 12 μM (and a growth K_m of 7 μM) and on d-mannitol with a K_m of 33 mM. Thus, the constitutive expression of the gut system restores the ability of mtlA mutants to grow on d-mannitol. Constitutivity of the gut operon also permits a double fruA and ptsM mutant to grow on d-fructose. Mutations in gutA prevent growth on d-glucitol, whereas mutations in gutD subject the cells to growth inhibition by the compound (401, 500, 505, 507).

Galactitol (or Dulcitol).

About one-half of E. coli isolates ferment galactitol (118, 212, 421). Those that do so use a pathway (Fig. 12) involving a specific enzyme II of the PTS which phosphorylates the substrate vectorially to give galactitol 1-phosphate. The product is then converted to d-tagatose 6-phosphate by an NAD-linked dehydrogenase (931). The enzyme II has a transport K_m of 3.3 μM for galactitol and a K_m of 0.3 mM for galactitol 1-phosphate. The genes sepecifying d-galactitol utilization are at min 47.2. The gatAD operon is transcribed in clockwise order, gatA encoding enzyme II^Gat and gatD encoding the dehydrogenase. The repressor gene, gutR, lies on the clockwise side of the operon. However, two other gene products are required to complete the degradative pathway. The 6-phosphofructokinase II encoded by pfkB at min 38 converts d-tagatose 6-phosphate to d-tagatose 1,6-biphosphate, which is then cleaved by a specific aldolase encoded by kba at min 69. Mutations in gatA prevent growth on galactitol, whereas mutations in gatD subject the cells to growth inhibition by the compound. Interestingly, even among substrains of E. coli K-12 there are differences in their Gat phenotypes. Most isolates do not grow on galactitol at any temperature. Galactitol-positive mutants can be isolated from these strains. Some isolates show growth impairment on the compound at temperatures above 30°C. The temperature sensitivity reflects the thermolability of the specific aldolase. Mutants selected for growth on galactitol at 42°C produce either more of the aldolase or a more stable form of it (189, 499, 500, 501, 667).

d-Arabitol, Ribitol, and Xylitol.

Less than 10% of E. coli isolates grow on ribitol (212). This small group includes strain C (the standard host strain for studies of phage P2) but not strain K-12 or B. Despite the great similarity of their genetic maps, there are morphological, as well as metabolic, differences between strains K-12 and C (516, 922). Strain C can grow on both ribitol and d-arabitol. The metabolism of each pentitol is initiated by an NAD-linked dehydrogenase to give a pentulose which is then phosphorylated by an ATP-dependent kinase (Fig. 8). Enzymes of the two parallel pathways are encoded at min 47 by two divergent operons which probably have overlapping regulatory regions and which are surrounded by inverted repeats believed to be vestiges of a transposable element. It was suggested that strains possessing the dual operons acquired them through a transposable element. The gene encoding d-arabitol dehydrogenase, atlD (or dalD), is promoter-proximal to the gene encoding d-xylulose kinase, atlK (or dalK). Similarly, the gene encoding ribitol dehydrogenase, rtlD (or rbtD), is promoter-proximal to the gene encoding d-ribulose kinase, rtlK (or rbtK). Each operon is under repressor control. Whereas the atl operon is induced by the substrate, d-arabitol, the rtl operon is induced by the product, d-ribulose. Strain C lacks the gat operon, which is present in strain K-12. When the atl operon is introduced into strain K-12 by transduction, it is integrated at min 47, replacing the gat operon as though these two operons were allelic (522, 523, 699, 764, 935). Mutants lacking d-arabitol dehydrogenase are sensitive to growth inhibition by the pentitol, because it is phosphorylated by the d-xylulose kinase to give a dead-end product. A similar situation holds for mutants lacking ribitol dehydrogenase and producing d-ribulose kinase constitutively (765).

Mutants of strain C can acquire the ability to grow on xylitol by a mutation that derepresses the rtlDK operon (763). In similar mutants of Klebsiella pneumoniae, the constitutively synthesized ribitol dehydrogenase converts xylitol to d-xylulose. The d-xylulose is partially reduced to d-arabitol by the basal level of d-arabitol oxidoreductase and causes induction of both the atlDK operon and the gene encoding d-arabitol permease. The permease has a side specificity for xylitol and accelerates its entry, and the atlK-encoded kinase phosphorylates the d-xylulose produced from xylitol by ribitol dehydrogenase (321, 322, 511, 580, 944).

Glycerol.

The proteins encoded by the glp regulon can be considered to be a system for salvaging the glycerol moiety of phospholipids and triglycerides after their breakdown. The degraded fragments can be utilized in the form of glycerophosphodiesters, sn-glycerol 3-phosphate (G3P), or glycerol (Fig. 13). Unlike other carbohydrates, glycerol enters the cytoplasm by facilitated diffusion across the cytoplasmic membrane. The facilitator protein provides a selective channel with an estimated pore size of 0.4 nm (27, 227, 334, 706, 759). Internal glycerol is trapped as G3P by the action of an ATP-dependent kinase that can also phosphorylate dihydroxyacetone (328). As a catabolic enzyme (a tetramer of a 55,000-Da subunit), the kinase has the unusual feature of being subject to noncompetitive allosteric inhibition by fructose 1,6-bisphosphate and the nonphosphorylated form of enzyme III^Glc, a feature which would account for the extreme effectiveness of glucose utilization in preventing glycerol consumption (190, 191, 192, 621, 855, 856, 857, 956, 957; W. Edgar, I. S. Forrest, W. H. Holmes, and B. Jasani, Biochem. J. 127:59, 1972) (see chapter 75). Although glycerol kinase is liberated as a soluble enzyme upon rupture of the cell, it is possible that in vivo the protein is physically associated with the facilitator protein. Glycerophosphodiesters entering the periplasmic compartment are hydrolyzed to G3P by a phosphodiesterase, a tetramer of a 40,000-Da subunit (41, 93, 474, 812). Whether liberated by hydrolysis in the periplasm or derived from the external environment, G3P is actively transported into the cytoplasm by a permease that functions as an oligomer of a subunit of about 33,000 Da (325, 475, 518, 781, 895). When the cells grow on G3P as the carbon and energy source, the excess phosphate derived is excreted by the same permease. The counterexchange of the organic and inorganic phosphates prevents toxic accumulation of P_i and spares the proton motive force required for G3P transport (217, 789; W. Boos, personal communication, 1984). G3P permease can transport a number of substrate analogs: l-glyceraldehyde 3-phosphate (847); fosfomycin (1,2-epoxypropyl-phosphonate), which is a bactericidal antibiotic (337, 414, 874); 3,4-dihydroxybutyl 1-phosphonate; and glycerol 3-phosphorothioate (308, 496, 636, 803, 804).

Fig. 13Metabolic pathways of glycerol and G3P.

Source:

Internal G3P can be converted to dihydroxyacetone-phosphate by two membrane enzyme complexes with flavin adenine dinucleotide serving as the coenzyme. The aerobic G3P dehydrogenase (a dimer of a 58,000-Da subunit) conducts the electrons to the cytochrome oxidases or to the nitrate reductase complex (169, 726, 777, 893, 894). Competition of this enzyme with other dehydrogenases for membrane attachment sites suggests the existence of specialized anchor units (459). The anaerobic G3P dehydrogenase conducts the electrons to the fumarate reductase complex or to the nitrate reductase complex (431, 433, 563). The extracted enzyme is a complex of a 62,000-Da subunit and a 43,000-Da subunit and contains one noncovalently bound flavin adenine dinucleotide and two nonheme irons. For functional attachment to the inner surface of the membrane, a third subunit is required (464, 778, 779). Metabolic energy is generated when G3P dehydrogenation is coupled to fumarate (approximately two protons extruded per fumarate molecule reduced) or nitrate reduction (84, 85, 446, 564, 565, 568, 814).

The glp structural genes comprising the regulon are not all linked. (i) The glpF gene encoding the facilitator and the glpK gene encoding the kinase are at min 88.4. The fact that mutations at this locus can lead to the simultaneous loss or increase of both glycerol kinase and glycerol permeability suggests that the two genes are in the same operon (72, 163, 170). (ii) The counterclockwise-transcribed glpTQ operon, with T encoding an integral membrane protein and Q encoding a glycerophosphodiesterase, is at min 48.6 (168, 475, 538, 567; W. Boos, personal communication, 1984). (iii) The clockwise-transcribed glpABC operon is a neighbor of glpTQ on the clockwise side. The A gene encodes anaerobic G3P dehydrogenase, and the B gene apparently encodes a membrane anchor protein (432, 464, 475, 566, 567). In addition, a promoter-distal open reading frame, gene C, was found (T. J. Larson, M. Ehrmann, and H. Schweizer, personal communication, 1986). The glpD operon encoding aerobic G3P dehydrogenase is at min 75.3 (168). In addition, two promoter-distal open reading frames, genes E and G, were found (T. J. Larson, M. Ehrmann, and H. Schweizer, personal communication, 1986).

Mutations in glpR, which is counterclockwise adjacent to glpD and encodes a 33,000-Da repressor, can lead to constitutivity or noninducibility of the glp regulon (168, 790). In wild-type cells, both glycerol and G3P induce the glp regulon, but in mutants lacking glycerol kinase only G3P has this effect (436). That the expression of the glp(KF) operon itself is also induced by G3P, rather than by glycerol, was demonstrated with a mutant that produces a glycerol kinase protein without catalytic activity. Thus, G3P seems to be the true inducer of the entire glp regulon (327). There is a possibility that d-galactose 1-phosphate acts as an anti-inducer (835a). Titration of a thermolabile repressor in a mutant by growth at increasing temperatures indicated that the repressor affinity of the glpD operator is about an order of magnitude higher than those of the other glp operators. This difference explains the relatively low basal level of aerobic G3P dehydrogenase, which offers the double advantage of curbing wasteful degradation of endogenous G3P and assuring rapid accumulation of G3P during induction. In repressor-constitutive mutants, glp(KF) and glpTQ are many times more sensitive to glucose repression than is glpD. Thus, catabolite repression acts primarily on the operons dealing with substrate input (168, 255, 436). As with other inducible catabolic pathways, mutations blocking the function of the PTS severely impede the induction of the glp system by causing cAMP deficiency and hindering inducer accumulation. Mutants lacking enzyme I of the PTS fail to grow on glycerol. The growth impairment can be physiologically remedied by cAMP supplementation or can be genetically suppressed by (i) abolition of glpR function; (ii) rendering of glycerol kinase insensitive to feedback inhibition by fructose 1,6-bisphosphate, thus allowing the inducer G3P to attain higher levels; or (iii) a mutation increasing the expression of glp(KF) (68, 69, 72). It can be predicted that mutations desensitizing the kinase from inhibition by III^Glc would also have a suppressing effect. An apparent glp(KF) promoter mutation allowed growth on glycerol without cAMP (252).

In a glpR mutant, the glpD-encoded dehydrogenase is synthesized at a high level during aerobic growth. The glpA-encoded dehydrogenase is synthesized at a high level during anaerobic growth, and this level is further increased by the addition of fumarate. The activity ratios of the two dehydrogenases can vary over 10-fold. Full anaerobic expression of the glpAB operon requires the pleiotropic Fnr protein. On the other hand, aerobic repression of the glpAB operon is partially relieved by the presence of cyanide or the blocking of heme synthesis. Anaerobic growth with nitrate, which can serve as a terminal electron hydrogen acceptor for either enzyme, gives intermediate levels of both dehydrogenases (255, 464). Probably as a result of inhibition of the nitrate electron-transport chain, the growth of a glpD mutant on glycerol-nitrate is instantly arrested upon the shift from anaerobiosis to aerobiosis (432).

In contrast to wild-type cells, which show a one-half maximal growth rate on glycerol at about 1 μM, mutants lacking glycerol facilitator show reduced growth rate on the substrate at concentrations below 5 mM (326, 706). In the presence of the facilitator, glycerol kinase activity controls the pace of substrate utilization, but it is important for the cell to keep this enzyme activity below certain limits. For instance, if catabolite repression is largely relieved by prior growth on casein hydrolysate, a constitutively produced glycerol kinase which is insensitive to fructose 1,6-bisphosphate inhibition renders the cell vulnerable to glycerol exposure. Under such a condition, the rapid accumulation of dihydroxyacetone-phosphate results in lethal formation of the highly chemically reactive methylglyoxal. The glycerol-susceptible cells can be rendered immune by selection for resistance to methylglyoxal. The resistant mutants produce an elevated level of a glutathione-dependent glyoxalase system and are actually able to grow on 1 mM methylglyoxal as sole carbon and energy source (254, 955). Lethal synthesis of methylglyoxal is not limited to unregulated glycerol catabolism; excessive uptake of other carbohydrates caused by lifting catabolite repression has a similar consequence (8). If a feedback-insensitive kinase is produced inducibly, the cell is not vulnerable to glycerol, even though the compound is utilized at an increased rate. Lethal synthesis of methylglyoxal is prevented by strong self-catabolite repression of glp(KF). In such cells, glycerol exerts a catabolite repressive effect on other inducible systems approaching that of glucose (955).

In addition to the importance of avoiding dihydroxyacetone-phosphate overproduction, it is vital for the cell to maintain its intracellular concentrations of G3P within a certain range under all growth conditions; its overproduction is bacteriostatic, and its overdegradation threatens the biosynthetic pool (517a). In mutants lacking aerobic G3P dehydrogenase, exposure to glycerol results in growth inhibition. The inhibitory effect, associated with depletion of intracellular ATP and other nucleoside triphosphates, can be overcome by glucose (169, 340).

Although glycerol is not chemostatic, at a threshold concentration of 1 mM it can act as a repellant, a process that involves all three methyl-accepting proteins (12, 631, 632). An NAD-linked dehydrogenase of broad specificity and uncertain physiological function, when constitutively expressed, is able to replace glycerol kinase for growth on glycerol (136, 137, 188, 395, 427, 428, 536, 827, 848, 849, 850).

S. typhimurium

Hexitols.

The mtl operon encoding enzyme II^Mtl and mannitol-1-phosphate dehydrogenase maps at min 78. d-Mannitol inhibits the growth of mutants lacking the dehydrogenase, in one case resulting in cell lysis. Mutations in mtlA can have differential effects on transport, phosphorylation, and chemotactic response (67, 391, 509, 751). The specific membrane complex for the utilization of d-glucitol involves two specific proteins: II and III (760). Although the gat operon was found to be inducible (189, 507), detailed analyses of the system have yet to be undertaken.

Inositol.

Most strains grow on meso-inositol, although many can do so at 25 but not 37°C (288, 627, 628). Vectorial phosphorylation is not known to be involved in the utilization of the cyclic hexitol. Instead, the first step of its degradation involves an NADP⁺-dependent dehydrogenation by 2-keto-myoinositol oxidoreductase. The keto compound is acted on by a dehydratase, and the resultant product is cleaved to 2-deoxy-5-keto-d-gluconate (835). With the exception of the dehydrogenation step requiring NAD instead of NADP, the rest of the pathway should be analogous to that in K. pneumoniae; the ketogluconate is phosphorylated at C-6 by an ATP-dependent kinase, and the product is then cleaved by an aldolase to dihydroxyacetone-phosphate and malonic semialdehyde (33, 34, 70, 71).

Glycerol.

All five operons of the glp regulon occupy positions homologous to those of E. coli: glpT and glpA at min 45, glpD and glpR at min 74, and glpK at min 87 (7, 339, 520, 695, 708, 756, 757). Glycerol kinase is feedback inhibited by fructose 1,6-bisphosphate and III^Glc (604, 621, 666, 752, 753).

CONCLUDING REMARKS

The carbohydrate moieties of ubiquitous macromolecules, e.g., DNA, RNA, phospholipids, glycogen, and oligosaccharides of cell surfaces, have all been shown to serve E. coli and S. typhimurium as sole carbon and energy sources, and most of the pathways involved have been completely characterized biochemically. Henceforth it will be a challenge to discover additional pathways (cryptic or in operation) in these organisms for carbon and energy sources that are metabolized by enzymes specified by chromosomal genes. Much, however, remains to be uncovered in the area of regulation. For most of the pathways, even the controls at the level of transcription have not been sufficiently characterized for the rules of induction to be understood. The process of uncovering translational controls and covalent modification of proteins that exist in some pathways is just beginning.

Although the catabolic pathways probably all have sufficiently evolved so that during the adapted state the intermediates will not accumulate unduly to burden the cell further with osmotic pressure or to cause interference with other metabolic processes, it is conceivable that temporary excesses are not always avoidable. Such excesses might occur when nutritional supplies change suddenly. There is no evidence that kinetic feedback is as well evolved in catabolic pathways as it is in biosynthetic pathways. Perhaps mechanisms for discharging excess catabolites have not received sufficient attention. The fact that the growth of mutants blocked at various reactions in catabolism is in general not noticeably inhibited by the substrate when the truncated pathway is induced would indicate the existence of discharge mechanisms that act as safety valves. (Even excessive biosynthetic intermediates can be excreted by auxotrophic mutants.) The notable exception is the growth arrest caused by a substrate whenever the further metabolism of a phosphorylated intermediate is mutationally blocked. This general phenomenon implicates the disturbance of a central regulatory mechanism (340) which deserves further study.

A wealth of important information about bacterial population genetics can be expected from comparative studies of the catabolic pathways. The judicious choice of systems studied under the right conditions might also increase our insight into the evolutionary forces that shaped the various kinds of catalytic and regulatory mechanisms.

ACKNOWLEDGMENTS

I thank S. Adhya, D. G. Fraenkel, J. Lengeler, A. Munch-Petersen, P. W. Postma, B. Rotman, H. A. Shuman, F. Stoeber, and A. Wright for helpful comments, and A. Ulrich for assistance in the preparation of this work. Studies in this laboratory were supported by Public Health Service grant 5-RO1-GM11983 from the National Institute of General Medical Sciences and by grant DMB8314312 from the National Science Foundation.

† The author regrets being unable, due to time pressures, to update this chapter with the considerable body of new information that has appeared since the first edition of this book was published.

References

1. Abou-Sabe, M. 1971. Isolation and characterization of Salmonella typhimurium d-ribose-positive revertants of Escherichia coli B-r. J. Gen. Microbiol. 65:375–377.

2. Abou-Sabe, M., J. Pilla, D. Hazuda, and A. Ninfa. 1982. Evolution of the d-ribose operon in Escherichia coli B/r. J. Bacteriol. 150:762–769.

3. Abou-Sabe, M., and P. L. Ratner. 1977. Genetic regulation of the constitutive d-ribose operon in Escherichia coli B/r. Biochim. Biophys. Acta 476:321–332.

4. Abou-Sabe, M., and J. Richman. 1973. On the regulation of d-ribose metabolism in Escherichia coli B/r. I. Isolation and characterization of d-ribokinaseless and d-ribose permeaseless mutants. Mol. Gen. Genet. 122:291–301.

5. Abou-Sabe, M., and J. Richman. 1973. On the regulation of d-ribose metabolism in Escherichia coli B/r. II. Chromosomal location and fine structure analysis of the d-ribose permease and d-ribokinase structural genes by P1 transduction. Mol. Gen. Genet. 122:303–312.

6. Abou-Sabe, M. A., and P. L. Ratner. 1973. Genetic regulation of a constitutive operon. Biochem. Biophys. Res. Commun. 55:1015–1020.

7. Aceves-Pina, E., M. V. Ortega, and M. Artis. 1974. Linkage of the Salmonella typhimurium chromosomal loci encoding for the cytochrome-linked l-alpha-glycerophosphate dehydrogenase and amylomaltase activities. Arch. Microbiol. 101:59–70.

8. Ackermann, R. S., N. R. Cozzarelli, and W. Epstein. 1974. Accumulation of toxic concentrations of methylgloxal by wild-type Escherichia coli K-12. J. Bacteriol. 119:357–362.

9. Adhya, S., and H. Echols. 1966. Glucose effect and the galactose enzymes of Escherichia coli: correlation between glucose inhibition of induction and inducer transport. J. Bacteriol. 92:601–608.

10. Adhya, S., and W. Miller. 1979. Modulation of the two promoters of the galactose operon of Escherichia coli. Nature (London) 279:492–494.

10a. Adhya, S. L., and J. A. Shapiro. 1969. The galactose operon of E. coli K-12. I. Structural and pleiotropic mutations of the operon. Genetics 62:231–247.

11. Adler, J., and W. Epstein. 1974. Phosphotransferase-system enzymes as chemoreceptors for certain sugars in Escherichia coli chemotaxis. Proc. Natl. Acad. Sci. USA 71:2895–2899.

12. Adler, J., G. L. Hazelbauer, and M. M. Dahl. 1973. Chemotaxis toward sugars in Escherichia coli. J. Bacteriol. 115:824–847.

13. Adler, J., and A. D. Kaiser. 1963. Mapping of the galactose genes of Escherichia coli by transduction with phage P1. Virology 19:117–126.

14. Ahlem, C., W. Huisman, G. Neslund, and A. S. Dahms. 1982. Purification and properties of a periplasmic d-xylose-binding protein from Escherichia coli K-12. J. Biol. Chem. 257:2926–2931.

15. Ahmad, S. I., P. T. Barth, and R. H. Pritchard. 1968. Properties of a mutant of Escherichia coli lacking purine nucleoside phosphorylase. Biochim. Biophys. Acta 161:581–583.

16. Ahmad, S. I., and R. H. Pritchard. 1969. A map of four genes specifying enzymes involved in catabolism of nucleosides and deoxynucleosides in Escherichia coli. Mol. Gen. Genet. 104:351–359.

17. Ahmad, S. I., and R. H. Pritchard. 1971. A regulatory mutant affecting the synthesis of enzymes involved in the catabolism of nucleosides in Escherichia coli. Mol. Gen. Genet. 111:77–83.

18. Ahmad, S. I., and R. H. Pritchard. 1973. An operator constitutive mutant affecting the synthesis of two enzymes involved in the catabolism of nucleosides in Escherichia coli. Mol. Gen. Genet. 124:321–329.

19. Aiba, H., S. Adhya, and B. de Crombrugghe. 1981. Evidence for two functional gal promoters in intact Escherichia coli cells. J. Biol. Chem. 256:11905–11910.

20. Akhy, M. T., C. M. Brown, and D. C. Old. 1984. l-Rhamnose utilisation in Salmonella typhimurium. J. Appl. Bacteriol. 56:269–274.

21. Aksamit, R., and D. E. Koshland, Jr. 1972. A ribose binding protein of Salmonella typhimurium. Biochem. Biophys. Res. Commun. 48:1348–1353.

22. Aksamit, R. R., and D. E. Koshland, Jr. 1974. Identification of the ribose binding protein as the receptor for ribose chemotaxis in Salmonella typhimurium. Biochemistry 13:4473–4478.

23. Alaeddinoglu, N. G., and H. P. Charles. 1979. Transfer of a gene for sucrose utilization into Escherichia coli K12, and consequent failure of expression of genes of d-serine utilization. J. Gen. Microbiol. 110:47–59.

24. Alber, T., M. Fahnestock, S. Mowbray, and G. Petsko. 1981. Preliminary X-ray data for the galactose binding protein from Salmonella typhimurium. J. Mol. Biol. 147:471–474.

25. Albrechtsen, H., and S. I. Ahmad. 1980. Regulation of the synthesis of nucleoside catabolic enzymes in Escherichia coli: further analysis of a deoO^c mutant strain. Mol. Gen. Genet. 179:457–460.

26. Albrechtsen, H., K. Hammer-Jespersen, A. Munch-Petersen, and N. Fiil. 1976. Multiple regulation of nucleoside catabolizing enzymes: effects of a polar dra mutation on the deo enzymes. Mol. Gen. Genet. 146:139–145.

27. Alemohammad, M. M., and C. J. Knowles. 1974. Osmotically induced volume and turbidity changes of Escherichia coli due to salts, sucrose and glycerol, with particular reference to the rapid permeation of glycerol into the cell. J. Gen. Microbiol. 82:125–142.

28. Alikhanian, S. I., T. S. Iljina, E. S. Kaliaeva, S. V. Kameneva, and V. V. Sukhodolec. 1966. A genetic study of thymineless mutants of Escherichia coli K12. Genet. Res. 8:83–100.

29. Alpers, D. H., S. H. Appel, and G. M. Tomkins. 1965. A spectrophotometric assay for thiogalactoside transacetylase. J. Biol. Chem. 240:10–13.

30. Al-Zarban, S., L. Heffernan, J. Nishitani, L. Ransone, and G. Wilcox. 1984. Positive control of the l-rhamnose genetic system in Salmonella typhimurium LT2. J. Bacteriol. 158:603–608.

31. Anderson, A., and R. A. Cooper. 1969. The significance of ribokinase for ribose utilization by Escherichia coli. Biochim. Biophys. Acta 177:163–165.

32. Anderson, A., and R. A. Cooper. 1970. Biochemical and genetical studies on ribose catabolism in Escherichia coli K12. J. Gen. Microbiol. 62:335–339.

33. Anderson, W. A., and B. Magasanik. 1971. The pathway of myo-inositol degradation in Aerobacter aerogenes. Identification of the intermediate 2-deoxy-5-keto-d-gluconic acid. J. Biol. Chem. 246:5653–5661.

34. Anderson, W. A., and B. Magasanik. 1971. The pathway of myo-inositol degradation in Aerobacter aerogenes. Conversion of 2-deoxy-5-keto-d-gluconic acid to glycolytic intermediates. J. Biol. Chem. 246:5662–5675.

35. Andrews, K. J., and E. C. C. Lin. 1976. Selective advantages of various bacterial carbohydrate transport mechanisms. Fed. Proc. 35:2185–2189.

36. Andrews, K. J., and E. C. C. Lin. 1976. Thiogalactoside transacetylase of the lactose operon as an enzyme for detoxification. J. Bacteriol. 128:510–513.

37. Anraku, Y. 1968. Transport of sugars and amino acids in bacteria. I. Purification and specificity of the galactose- and leucine-binding proteins. J. Biol. Chem. 243:3116–3122.

38. Anraku, Y. 1968. Transport of sugars and amino acids in bacteria. II. Properties of galactose- and leucine-binding proteins. J. Biol. Chem. 243:3123–3127.

39. Anraku, Y. 1968. Transport of sugars and amino acids in bacteria. III. Studies on the restoration of active transport. J. Biol. Chem. 243:3128–3135.

40. Arditti, R. R., J. G. Scaife, and J. R. Beckwith. 1968. The nature of mutants in the lac promoter region. J. Mol. Biol. 38:421–426.

41. Argast, M., G. Schumacher, and W. Boos. 1977. Characterization of a periplasmic protein related to sn-glycerol-3-phosphate transport in E. coli. J. Supramol. Struct. 6:135–153.

42. Argos, P., W. C. Mahoney, M. A. Hermodson, and M. Hanei. 1981. Structural predictions of sugar binding proteins functional in chemotaxis and transport. J. Biol. Chem. 256:4357–4361.

43. Arr, M., T. Perenyi, and E. K. Novak. 1970. Sucrose and raffinose breakdown by Escherichia coli. Acta Microbiol. Acad. Sci. Hung. 17:117–126.

44. Arraj, J. A., and J. H. Campbell. 1975. Isolation and characterization of the newly evolved ebg β-galactosidase of Escherichia coli K-12. J. Bacteriol. 124:849–856.

45. Ashwell, G. 1962. Enzymes of glucuronic and galacturonic acid metabolism in bacteria. Methods Enzymol. 5:190–208.

46. Ashwell, G., A. J. Wahba, and J. Hickman. 1958. A new pathway of uronic acid metabolism. Biochim. Biophys. Acta 30:186–187.

47. Ashwell, G., A. J. Wahba, and J. Hickman. 1960. Uronic acid metabolism in bacteria. I. Purification and properties of uronic acid isomerase in Escherichia coli. J. Biol. Chem. 235:1559–1565.

48. Atherly, A. G. 1979. Escherichia coli mutant containing a large deletion from relA to argA. J. Bacteriol. 138:530–534.

49. Autissier, F., and A. Kepes. 1972. Segregation de marqueurs membranaires au cours de la croissance et de la division d’Escherichia coli. III. Utilisation de marqueurs variés: permeases, phosphotransferases, oxydoreductases membranaires. Biochimie 54:93–101.

49a. Babul, J. 1978. Phosphofructokinases from Escherichia coli: purification and characterization of the nonallosteric isozyme. J. Biol. Chem. 253:4350–4355.

50. Bächi, B., and H. L. Kornberg. 1973. Genes involved in the uptake and catabolism of gluconate by Escherichia coli. J. Gen. Microbiol. 90:321–335.

51. Bachmann, B. J. 1983. Linkage map of Escherichia coli K-12, edition 7. Microbiol. Rev. 47:180–230.

52. Badia, J., J. Ros, and J. Aguilar. 1985. Fermentation mechanism of fucose and rhamnose in Salmonella typhimurium and Klebsiella pneumoniae. J. Bacteriol. 161:435–437.

53. Baron, L. S., W. F. Carey, and W. M. Spilman. 1959. Characteristics of a high frequency of recombination (Hfr) strain of Salmonella typhosa compatible with Salmonella, Shigella, and Escherichia species. Proc. Natl. Acad. Sci. USA 45:1752–1757.

54. Baron, L. S., W. F. Carey, and W. M. Spilman. 1959. Genetic recombination between Escherichia coli and Salmonella typhimurium. Proc. Natl. Acad. Sci. USA 45:976–984.

55. Barth, P. T., I. R. Beacham, S. I. Ahmad, and R. H. Pritchard. 1968. The inducer of the deoxynucleoside phosphorylases and deoxyriboaldolase in Escherichia coli. Biochim. Biophys. Acta 161:554–557.

56. Batt, C. A., M. S. Bodis, S. K. Pacataggio, M. C. Claps, S. Jamas, and A. J. Sinskey. 1985. Analysis of xylose operon regulation by Mud (Ap^r, lac) fusion: trans effect of plasmid coded xylose operon. Can. J. Microbiol. 31:930–933.

57. Baudouy-Robert, J., M.-L. Didier-Fichet, J. Jimeno-Abendano, G. Novel, R. Portalier, and F. Stoeber. 1970. Modalités de l’induction des six premières enzymes degradant les hexuronides et les hexuronates chez Escherichia coli K-12. C. R. Acad. Sci. Ser. D 271:255–258.

58. Baumanis, G. E., Y. V. Smirnov, and V. V. Sukhodoletz. 1974. Production and study of polar mutants for nucleoside catabolism linked genes in Escherichia coli. Genetika 10:81–88.

59. Bavoil, P., M. Hofnung, and H. Nikaido. 1980. Identification of a cytoplasmic membrane-associated component of the maltose transport system of Escherichia coli. J. Biol. Chem. 255:8366–8369.

60. Bavoil, P., and H. Nikaido. 1981. Physical interaction between the phage lambda receptor protein and the carrier-immobilized maltose binding protein of Escherichia coli. J. Biol. Chem. 256:11385–11388.

61. Beacham, I. R., A. Eisenstark, P. T., Barth, and R. H. Pritchard. 1968. Deoxynucleoside-sensitive mutants of Salmonella typhimurium. Mol. Gen. Genet. 102:112–127.

62. Beacham, I. R., E. Yagil, K. Beacham, and R. H. Pritchard. 1971. On the localization of enzymes of deoxynucleoside catabolism in Escherichia coli. FEBS Lett. 16:77–80.

63. Becerra de Lares, L., J. Ratouchniak, and F. Casse. 1977. Chromosomal location of genes governing the trehalose utilization in Escherichia coli K-12. Mol. Gen. Genet. 152:105–108.

64. Beck, C. F., and J. L. Ingraham. 1971. Location on the chromosome of Salmonella typhimurium of genes governing pyrimidine metabolism. Mol. Gen. Genet. 111:303–316.

65. Beck, C. F., J. L. Ingraham, J. Neuhard, and E. Thomassen. 1972. Metabolism of pyrimidines and pyrimidine nucleosides by Salmonella typhimurium. J. Bacteriol. 110:219–228.

66. Beckwith, J. 1963. Restoration of operon activity by suppressors. Biochim. Biophys. Acta 76:162–164.

67. Berkowitz, D. 1971. d-Mannitol utilization in Salmonella typhimurium. J. Bacteriol. 105:232–240.

68. Berman, M., and E. C. C. Lin. 1971. Glycerol-specific revertants of a phosphoenolpyruvate phosphotransferase mutant: suppression by the desensitization of glycerol kinase to feedback inhibition. J. Bacteriol. 105:113–120.

69. Berman, M., N. Zwaig, and E. C. C. Lin. 1970. Suppression of a pleiotropic mutant affecting glycerol dissimilation. Biochem. Biophys. Res. Commun. 38:272–278.

70. Berman, T., and B. Magasanik. 1966. The pathway of myo-inositol degradation in Aerobacter aerogenes. Dehydrogenation and dehydration. J. Biol. Chem. 241:800–806.

71. Berman, T., and B. Magasanik. 1966. The pathway of myo-inositol degradation in Aerobacter aerogenes. Ring scission. J. Biol. Chem. 241:807–813.

72. Berman-Kurtz, M., E. C. C. Lin, and D. P. Richey. 1971. Promoter-like mutant with increased expression of the glycerol kinase operon of Escherichia coli. J. Bacteriol. 106:724–731.

73. Bernheim, N. J., and W. J. Dobrogosz. 1970. Amino sugar sensitivity in Escherichia coli mutants unable to grow on N-acetylglycosamine. J. Bacteriol. 101:384–391.

74. Bewick, M. A., and T. C. Y. Lo. 1979. Dicarboxylic acid transport in Escherichia coli K-12: involvement of a binding protein in the translocation of dicarboxylic acids across the outer membrane of the cell envelope. Can. J. Biochem. 57:653–661.

75. Bewick, M. A., and T. C. Y. Lo. 1980. Localization of the dicarboxylate binding protein in the cell envelope of Escherichia coli K12. Can. J. Biochem. 58:885–897.

76. Bhattacharya, A. K., and M. Chakravorty. 1971. Induction and repression of l-arabinose isomerase in Salmonella typhimurium. J. Bacteriol. 106:107–112.

77. Bhattacharya, A. K., and M. Chakravorty. 1974. Effect of antibiotics and antimetabolites on the induction of l-arabinose isomerase in Salmonella typhimurium. Curr. Sci. 43:499–503.

78. Bhattacharya, A. K., and M. Chakravorty. 1975. Isolation and characterization of an l-arabinose negative mutant of Salmonella typhimurium. Indian J. Exp. Biol. 13:244–246.

79. Blanco, C., M. Mata-Gilsinger, and P. Ritzenthaler. 1983. Construction of hybrid plasmids containing the Escherichia coli uxaB gene: analysis of its regulation and direction of transcription. J. Bacteriol. 153:747–755.

80. Blanco, C., P. Ritzenthaler, and M. Mata-Gilsinger. 1982. Cloning and endonuclease restriction analysis of uidA and uidR genes in Escherichia coli K-12: determination of transcription direction for the uidA gene. J. Bacteriol. 149:587–594.

81. Blank, J., and P. Hoffee. 1972. Regulatory mutants of the deo regulon in Salmonella typhimurium. Mol. Gen. Genet. 116:291–298.

82. Blank, J. G., and P. A. Hoffee. 1975. Purification and properties of thymidine phosphorylase from Salmonella typhimurium. Arch. Biochem. Biophys. 168:259–265.

83. Bonney, R. J., and H. Weinfeld. 1971. Regulation of thymidine metabolism in Escherichia coli K-12: studies on the inducer and the coordinateness of induction of the enzymes. J. Bacteriol. 106:812–818.

84. Boonstra, J., M. T. Huttunen, W. N. Konings, and H. R. Kaback. 1975. Anaerobic transport in Escherichia coli membrane vesicles. J. Biol. Chem. 250:6792–6898.

85. Boonstra, J., H. J. Sips, and W. N. Konings. 1976. Active transport by membrane vesicles from anaerobically grown Escherichia coli energized by electron transfer to ferricyanide and chlorate. Eur. J. Biochem. 69:35–44.

86. Boos, W. 1969. The galactose binding protein and its relationship to the beta-methylgalactoside permease from Escherichia coli. Eur. J. Biochem. 10:66–73.

87. Boos, W. 1972. Structurally defective galactose-binding protein isolated from a mutant negative in the beta-methylgalactoside transport system of Escherichia coli. J. Biol. Chem. 247:5414–5424.

88. Boos, W. 1974. Pro and contra carrier proteins: sugar transport via the periplasmic galactose-binding protein. Curr. Top. Membr. Transp. 5:51–136.

89. Boos, W. 1982. Aspects of maltose transport in Escherichia coli: established facts and educated guesses. Ann. Inst. Pasteur Microbiol. 133A:145–151.

90. Boos, W., T. Ferenci, and H. A. Shuman. 1981. Formation and excretion of acetylmaltose after accumulation of maltose in Escherichia coli. J. Bacteriol. 146:725–732.

91. Boos, W., and A. S. Gordon. 1971. Transport properties of the galactose-binding protein of Escherichia coli. J. Biol. Chem. 246:621–628.

92. Boos, W., A. S. Gordon, R. Z. Hall, and H. D. Price. 1972. Transport properties of the galactose-binding protein of Escherichia coli. J. Biol. Chem. 247:917–924.

93. Boos, W., I. Hartig-Beecken, and K. Altendorf. 1977. Purification and properties of a periplasmic protein related to sn-glycerol-3-phosphate transport in Escherichia coli. Eur. J. Biochem. 72:571–581.

94. Boos, W., and M. O. Sarvas. 1970. Close linkage between a galactose-binding protein and the beta-methylgalactoside permease in Escherichia coli. Eur. J. Biochem. 13:526–533.

95. Boos, W., and L. Staehelin. 1981. Ultrastructural localization of the maltose-binding protein within the cell envelope of Escherichia coli. Arch. Mikrobiol. 129:240–246.

96. Boos, W., I. Steinacher, and D. Engelhardt-Altendorf. 1981. Mapping of mglB, the structural gene of the galactose-binding protein of Escherichia coli. Mol. Gen. Genet. 184:508–518.

97. Boos, W., and K. Wallenfels. 1968. Untersuchungen zur Induktion der Lac-Enzyme. 2. Die Permeation von Galaktosylglyzerin in Escherichia coli. Eur. J. Biochem. 3:360–363.

98. Boronat, A., and J. Aguilar. 1979. Rhamnose-induced propanediol oxidoreductase in Escherichia coli: purification, properties, and comparison with the fucose-induced enzyme. J. Bacteriol. 140:320–326.

99. Boronat, A., and J. Aguilar. 1981. Experimental evolution of propanediol oxidoreductase in Escherichia coli. Comparative analysis of the wild-type and mutant enzymes. Biochim. Biophys. Acta 672:98–107.

100. Boronat, A., and J. Aguilar. 1981. Metabolism of l-fucose and l-rhamnose in Escherichia coli: differences in induction of propanediol oxidoreductase. J. Bacteriol. 147:181–185.

101. Boronat, A., E. Caballero, and J. Aguilar. 1983. Experimental evolution of a metabolic pathway for ethylene glycol utilization by Escherichia coli. J. Bacteriol. 153:134–139.

102. Boronat, A., M. C. Jones-Mortimer, and H. L. Kornberg. 1982. A specialized transducing phage, lambda psrlA, for the sorbitol phosphotransferase of Escherichia coli K12. J. Gen. Microbiol. 128:605–611.

103. Bose, R., and E. W. Yamada. 1974. Uridine phosphorylase, molecular properties and mechanism of catalysis. Biochemistry 13:2051–2056.

104. Boulter, J., B. Gielow, M. McFarland, and N. Lee. 1974. Metabolism of d-arabinose by Escherichia coli B/r. J. Bacteriol. 117:920–923.

105. Boulter, J. R., and W. O. Gielow. 1973. Properties of d-arabinose isomerase purified from two strains of Escherichia coli. J. Bacteriol. 113:687–696.

106. Boyer, H., E. Englesberg, and R. Weinberg. 1962. Direct selection of l-arabinose negative mutants of Escherichia coli strain B/r. Genetics 47:417–425.

107. Brass, J. M., K. Bauer, U. Ehmann, and W. Boos. 1985. Maltose-binding protein does not modulate the activity of maltoporin as a general porin in Escherichia coli. J. Bacteriol. 161:720–726.

108. Brass, J. M., and M. D. Manson. 1984. Reconstitution of maltose chemotaxis in Escherichia coli by addition of maltose-binding protein to calcium-treated cells of maltose regulon mutants. J. Bacteriol. 157:881–890.

109. Braun, V., and H. J. Krieger-Brauer. 1977. Interrelationship of the phage lambda receptor protein and maltose transport in mutants of Escherichia coli K12. Biochim. Biophys. Acta 469:89–98.

110. Braun-Breton, C., and M. Hofnung. 1981. In vivo and in vitro functional alterations of the bacteriophage lambda receptor in lamB mutants. J. Bacteriol. 148:845–852.

111. Breitman, T. R., and R. M. Bradford. 1964. The induction of thymidine phosphorylase and excretion of deoxyribose during thymine starvation. Biochem. Biophys. Res. Commun. 17:786–791.

112. Breitman, T. R., and R. M. Bradford. 1967. The absence of deoxyriboaldolase activity in the thymineless mutant of Escherichia coli strain 15. A possible explanation for the low thymine requirement of some thymineless strains. Biochim. Biophys. Acta 138:217–220.

113. Breitman, T. R., and R. M. Bradford. 1968. Inability of low thymine-requiring mutants of Escherichia coli lacking phosphodeoxyribomutase to be induced for deoxythymidine phosphorylase and deoxyriboaldolase. J. Bacteriol. 95:2434–2435.

114. Brown, C. E., and R. W. Hogg. 1972. A second transport system for l-arabinose in Escherichia coli B-r controlled by the araC gene. J. Bacteriol. 111:606–613.

115. Brown, J. L., D. M. Brown, and I. Zabin. 1967. Thiogalactoside transacetylase: physical and chemical studies of subunit structure. J. Biol. Chem. 242:4254–4258.

116. Brown, J. L., S. Koorajian, and I. Zabin. 1967. Thiogalactoside transacetylase: amino- and carboxyl-terminal studies. J. Biol. Chem. 242:4259–4264.

117. Buchanan, C. E., and A. Markowtiz. 1973. Depression of uridine diphosphate-glucose pyrophosphorylase (galU) in capR (lon), capS, and capT mutants and studies on the galU repressor. J. Bacteriol. 115:1011–1020.

118. Buchanan, R. E., and N. E. Gibbons (ed.). 1974. Bergey’s Manual of Determinative Bacteriology, 8th ed. The Williams & Wilkins Co., Baltimore.

119. Budman, D. R., and A. B. Pardee. 1967. Thymidine and thymine incorporation into deoxyribonucleic acid: inhibition and repression by uridine of thymidine phosphorylase of Escherichia coli. J. Bacteriol. 94:1546–1550.

120. Burstein, C., M. Cohn, A. Kepes, and J. Monod. 1965. Role du lactose et de ses produits metaboliques dans l’induction de l’operon lactose chez Escherichia coli. Biochim. Biophys. Acta 95:634–639.

121. Burstein, C., and A. Kepes. 1966. Mise en evidence d’α-galactosidase dans des extraits acellulaires de Escherichia coli. C.R. Acad. Sci. Ser. D 262:227–229.

122. Burstein, C., and A. Kepes. 1971. The beta-galactosidase from Escherichia coli K12. Biochim. Biophys. Acta 230:52–63.

123. Burton, K. 1977. Transport of adenine, hypoxanthine and uracil into Escherichia coli. Biochem. J. 168:195–204.

124. Busby, S., H. Aiba, and B. de Crombrugghe. 1982. Mutations in the Escherichia coli operon that define two promoters and the binding site of the cyclic AMP receptor protein. J. Mol. Biol. 154:211–227.

125. Busby, S., M. Irani, and B. de Crombrugghe. 1982. Isolation of mutant promoters in the Escherichia coli galactose operon using local mutagenesis on cloned DNA fragments. J. Mol. Biol. 154:197–209.

126. Buttin, G. 1962. Sur la structure de l’operon galactose chez Escherichia coli K12. C.R. Acad. Sci. Ser. D 255:1233–1235.

127. Buttin, G. 1963. Mécanismes regulateurs dans la biosynthèse des enzymes du metabolisme du galactose chez Escherichia coli K-12. I. La biosynthése induite de la galactokinase et l’induction simultanée de la sequence enzymatique. J. Mol. Biol. 7:164–182.

128. Buttin, G. 1963. Mécanismes regulateurs dans la biosynthèse des enzymes du metabolisme du galactose chez Escherichia coli K-12. II. Le determinisme génétique de la regulation. J. Mol. Biol. 7:183–205.

129. Buxton, R. S. 1975. Genetic analysis of thymidine-resistant and low-thymine-requiring mutants of Escherichia coli K-12 induced by bacteriophage Mu-1. J. Bacteriol. 121:475–484.

130. Buxton, R. S. 1979. Fusion of the lac genes to the proximal promoters of the deo operon of Escherichia coli K 12. J. Gen. Microbiol. 112:241–250.

131. Buxton, R. S., H. Albrechtsen, and K. Hammer-Jespersen. 1977. Overlapping transcriptional units in the deo operon of Escherichia coli K 12: evidence from phage Mu-1 insertion mutants. J. Mol. Biol. 114:287–300.

132. Buxton, R. S., K. Hammer-Jespersen, and T. D. Hansen. 1978. Insertion of bacteriophage lambda into the deo operon of Escherichia coli K-12 and isolation of plaque-forming lambda deo ⁺ transducing bacteriophage. J. Bacteriol. 136:668–681.

133. Buxton, R. S., K. Hammer-Jespersen, and P. Valentin-Hansen. 1980. A second purine nucleoside phosphorylase in Escherichia coli K-12. I. Xanthosine phosphorylase regulatory mutants isolated as secondary-site revertants of a deoD mutant. Mol. Gen. Genet. 179:331–340

134. Caballero, E., L. Baldoma, J. Ros, A. Boronat, and J. Aguilar. 1983. Identification of lactaldehyde dehydrogenase and glycolaldehyde dehydrogenase as functions of the same protein in Escherichia coli. J. Biol. Chem. 258:7788–7792.

135. Campbell, J. J., J. Lengyel, and J. Langridge. 1973. Evolution of a second gene for beta-galactosidase in Escherichia coli. Proc. Natl. Acad. Sci. USA 70:1841–1845.

136. Campbell, R. L., and E. E. Dekker. 1973. Formation of d-1-amino-2-propanol from l-threonine by enzymes from Escherichia coli K-12. Biochem. Biophys. Res. Commun. 53:432–438.

137. Campbell, R. L., R. R. Swain, and E. E. Dekker. 1978. Purification, separation, and characterization of two molecular forms of d-1-amino-2-propanol:NAD⁺ oxidoreductase activity from extracts of Escherichia coli K-12. J. Biol. Chem. 253:7282–7288.

138. Chakrabarti, T., Y.-M. Chen, and E. C. C. Lin. 1984. Clustering of genes for l-fucose dissimilation by Escherichia coli. J. Bacteriol. 157:984–986.

139. Chelala, C. A., and P. Margolin. 1984. Effects of deletions on cotransduction linkage in Salmonella typhimurium: evidence that bacterial chromosome deletions affect the formation of transducing DNA fragments. Mol. Gen. Genet. 131:97–112.

140. Chen, Y.-M., T. Chakrabarti, and E. C. C. Lin. 1984. Constitutive activation of l-fucose genes by an unlinked mutation in Escherichia coli. J. Bacteriol. 159:725–729.

141. Chen, Y.-M., E. C. C. Lin, J. Ros, and J. Aguilar. 1983. Use of operon fusions to examine the regulation of the l-1,2-propanediol oxidoreductase gene of the fucose system in Escherichia coli. J. Gen. Microbiol. 129:3355–3362.

142. Chen, Y.-M., and E. C. C. Lin. 1984. Post-transcriptional control of l-1,2-propanediol oxidoreductase in the l-fucose pathway of Escherichia coli K-12. J. Bacteriol. 157:341–344.

143. Chen, Y.-M., and E. C. C. Lin. 1984. Dual control of a common l-1,2-propanediol oxidoreductase by l-fucose and l-rhamnose in Escherichia coli. J. Bacteriol. 157:828–832.

144. Chiu, T.-H., K. L. Evans, and D. S. Feingold. 1975. l-Rhamnulose-1-phosphate aldolase. Methods Enzymol. 42:264–269.

145. Chiu, T. H., and D. S. Feingold. 1964. The purification and properties of l-rhamnulokinase. Biochim. Biophys. Acta 92:489–497.

146. Chiu, T. H., and D. S. Feingold. 1965. Substrate specificity of l-rhamnulose 1-phosphate aldolase. Biochem. Biophys. Res. Commun. 19:511–516.

147. Chiu, T. H., and D. S. Feingold. 1969. l-Rhamnulose 1-phosphate aldolase from Escherichia coli. Crystallization and properties. Biochemistry 8:98–108.

148. Clark, A. F., T. A. Gerken, and R. W. Hogg. 1982. Proton nuclear magnetic resonance spectroscopy and ligand binding dynamics of the Escherichia coli l-arabinose binding protein. Biochemistry 21:2227–2233.

149. Clark, A. F., and R. W. Hogg. 1981. High-affinity arabinose transport mutants of Escherichia coli: isolation and gene location. J. Bacteriol. 147:920–924.

150. Clarke, P., H.-C. Lin, and G. Wilcox. 1982. The nucleotide sequence of the araC regulatory gene in Salmonella typhimurium LT2. Gene 18:157–163.

151. Clement, J. M., and M. Hofnung. 1981. Gene sequence of the lambda receptor, an outer membrane protein of E. coli K12. Cell 27:507–514.

152. Cocks, G. T., J. Aguilar, and E. C. C. Lin. 1974. Evolution of l-1,2-propanediol catabolism in Escherichia coli by recruitment of enzymes for l-fucose and l-lactate metabolism. J. Bacteriol. 118:83–88.

153. Cohen, R. M., and R. Wolfenden. 1971. Cytidine deaminase from Escherichia coli. J. Biol. Chem. 246:7561–7565.

154. Cohen, R. M., and R. Wolfenden. 1971. The equilibrium of hydrolytic deamination of cytidine and N⁴-methylcytidine. J. Biol. Chem. 246:7566–7568.

155. Cohen, S., and R. Raff. 1951. Adaptive enzymes in the metabolism of gluconate, d-arabinose and d-ribose. J. Biol. Chem. 188:501–508.

156. Cohen, S. S. 1949. Adaptive enzyme formation in the study of uronic acid utilization by the K-12 strain of Escherichia coli. J. Biol. Chem. 177:607–619.

157. Cohen, S. S. 1953. Studies on controlling mechanisms in the metabolism of virus-infected bacteria. Cold Spring Harbor Symp. Quant. Biol. 18:221–235.

158. Cohen, S. S. 1953. Studies on d-ribulose and its enzymatic conversion to d-arabinose. J. Biol. Chem. 201:72–84.

159. Cohen, S. S., and H. D. Barner. 1957. The conversion of 5-methyldeoxycytidine to thymidine in vitro and in vivo. J. Biol. Chem. 226:631–642.

160. Cohn, M., and J. Monod. 1951. Purification et propriétés de la beta-galactosidase (lactase) d’Escherichia coli. Biochim. Biophys. Acta 7:153–174.

161. Comb, D. G., and S. Rosemand. 1956. Glucosamine-6-phosphate deaminase. Biochim. Biophys. Acta 21:193–194.

162. Comb, D. G., and S. Rosemand. 1958. Glucosamine metabolism. IV. Glucosamine-6-phosphate deaminase. J. Biol. Chem. 232:807–827.

163. Conrad, C. A., G. W. Stearns III, W. E. Prater, J. A. Rheiner, and J. R. Johnson. 1984. Characterization of a glpK transducing phage. Mol. Gen. Genet. 193:376–378.

164. Cooper, R. A. 1978. The utilisation of d-galactonate and d-2-oxo-3-deoxygalactonate by Escherichia coli K-12. Arch. Microbiol. 118:199–206.

165. Corina, D. L., and D. C. Wilton. 1976. An apparent lack of stereospecificity in the reaction catalyzed by deoxyribose 5-phosphate aldolase due to methyl-group rotation and enolization before product release. Biochem. J. 157:573–576.

166. Cornelis, G., D. Ghosal, and H. Saedler. 1978. Tn951: a new transposon carrying a lactose operon. Mol. Gen. Genet. 160:215–224.

167. Cornelis, G., R. K. J. Luke, and M. H. Richmond. 1978. Fermentation of raffinose by lactose-fermenting strains of Yersinia enterocolitica and by sucrose-fermenting strains of Escherichia coli. J. Clin. Microbiol. 7:180–183.

168. Cozzarelli, N. R., W. B. Freedberg, and E. C. C. Lin. 1968. Genetic control of the l-alpha-glycerophosphate system in Escherichia coli. J. Mol. Biol. 31:371–387.

169. Cozzarelli, N. R., J. P. Koch, S. Hayashi, and E. C. C. Lin. 1965. Growth stasis by accumulated l-alpha-glycerophosphate in Escherichia coli. J. Bacteriol. 90:1325–1329.

170. Cozzarelli, N. R., and E. C. C. Lin. 1966. Chromosomal location of the structural gene for glycerol kinase in Escherichia coli. J. Bacteriol. 91:1763–1766.

171. Csonka, L. N., and A. J. Clark. 1979. Deletions generated by the transposon Tn10 in the srl recA region of the Escherichia coli K-12 chromosome. Genetics 93:321–343.

172. Csonka, L. N., and A. J. Clark. 1980. Construction of an Hfr strain useful for transferring recA mutations between Escherichia coli strains. J. Bacteriol. 143:529–530.

173. Curtis, S. J. 1974. Mechanism of energy coupling for transport of d-ribose in Escherichia coli. J. Bacteriol. 120:295–303.

174. Curtis, S. J., and W. Epstein. 1975. Phosphorylation of d-glucose in Escherichia coli mutants defective in glucose phosphotransferase, mannose phosphotransferase, and glucokinase. J. Bacteriol. 122:1189–1199.

175. Cynkin, M. A., and G. Ashwell. 1960. Uronic acid metabolism in bacteria. IV. Purification and properties of 2-keto-3-deoxy-d-gluconokinase in Escherichia coli. J. Biol. Chem. 235:1576–1579.

176. Dabbs, E. R. 1980. The gene for ribosomal protein S21, rpsU, maps close to dnaG at 66.5 min on the Escherichia coli chromosomal linkage map. J. Bacteriol. 144:603–607.

177. Dale, B., and G. R. Greenberg. 1967. Genetic mapping of a mutation in Escherichia coli showing reduced activity of thymidine phosphorylase. J. Bacteriol. 94:778–779.

178. Dandanell, G., and K. Hammer. 1985. Two operator sites separated by 599 base pairs are required for deoR repression of the deo operon of Escherichia coli. EMBO J. 4:3333–3338.

179. Daruwalla, K. R., A. T. Paxton, and P. J. F. Henderson. 1981. Energization of the transport systems for arabinose and comparison with galactose transport in Escherichia coli. Biochem. J. 200:611–627.

180. David, J., and H. Wiesmeyer. 1970. Regulation of ribose metabolism in Escherichia coli. I. The ribose catabolic pathway. Biochim. Biophys. Acta 208:45–55.

181. David, J., and H. Wiesmeyer. 1970. Regulation of ribose metabolism in Escherichia coli. II. Evidence for two ribose-5-phosphate isomerase activities. Biochim. Biophys. Acta 208:56–67.

182. David, J., and H. Wiesmeyer. 1970. Regulation of ribose metabolism in Escherichia coli. III. Regulation of ribose utilization in vivo. Biochim. Biophys. Acta 208:68–76.

183. David, J. D., and H. Wiesmeyer. 1970. Control of xylose metabolism in Escherichia coli. Biochim. Biophys. Acta 201:497–499.

184. Davis, E. O., M. C. Jones-Mortimer, and P. J. F. Henderson. 1984. Location of a structural gene for xylose-H⁺ symport at 91 min on the linkage map of Escherichia coli K12. J. Biol. Chem. 259:1520–1525.

185. Deacon, J., and R. A. Cooper. 1977. d-Galactonate utilization by enteric bacteria. The catabolic pathway in Escherichia coli. FEBS Lett. 77:201–205.

186. Defez, R., and M. De Felice. 1981. Cryptic operon for beta-glucoside metabolism in Escherichia coli K12: genetic evidence for a regulatory protein. Genetics 97:11–25.

187. Defez, R., and M. De Felice. 1982. The metabolism of beta-glucosides in Escherichia coli K-12. Ann. Microbiol. (Paris) 133A:347–350.

188. Dekker, E. E., and R. R. Swain. 1968. Formation of dg-1-amino-2-propanol by a highly purified enzyme from Escherichia coli. Biochim. Biophys. Acta 158:306–307.

189. Delidakis, C. E., M. C. Jones-Mortimer, and H. L. Kornberg. 1982. A mutant inducible for galactitol utilization in Escherichia coli K12. J. Gen. Microbiol. 128:601–604.

190. de Riel, J. K., and H. Paulus. 1978. Subunit dissociation in the allosteric regulation of glycerol kinase from Escherichia coli. 1. Kinetic evidence. Biochemistry 17:5134–5140.

191. de Riel, J. K., and H. Paulus. 1978. Subunit dissociation in the allosteric regulation of glycerol kinase from Escherichia coli. 2. Physical evidence. Biochemistry 17:5141–5145.

192. de Riel, J. K., and H. Paulus. 1978. Subunit dissociation in the allosteric regulation of glycerol kinase from Escherichia coli. 3. Role in desensitization. Biochemistry 17:5146–5150.

193. Didier-Fichet, M.-L., and F. Stoeber. 1968. Sur les activités glucuronidasique et galacturonidasique d’Escherichia coli. C.R. Acad. Sci. Ser. D 266:1894–1897.

194. Didier-Fichet, M.-L., and F. Stoeber. 1968. Sur les propriétés et la biosynthèse de la beta-glucuronidase d’Escherichia coli K-12. C.R. Acad. Sci. Ser. D 266:2021–2024.

195. Dietz, G. W. 1972. Dehydrogenase activity involved in the uptake of glucose 6-phosphate by a bacterial membrane system. J. Biol. Chem. 247:4561–4565.

196. Dietz, G. W., and L. A. Heppel. 1971. Studies on the uptake of hexose phosphates. II. The induction of the glucose-6-phosphate transport system by exogenous but not by endogenously formed glucose-6-phosphate. J. Biol. Chem. 246:2885–2890.

197. Dietz, G. W., Jr. 1976. The hexose phosphate transport system of Escherichia coli. Adv. Enzymol. 44:237–259.

198. diLauro, R., T. Taniguchi, R. Musso, and B. de Crombrugghe. 1979. Unusual location and function of the operator in the Escherichia coli galactose operon. Nature (London) 279:494–500.

199. DiNardo, S., K. A. Voelkel, and R. Sternglanz. 1982. Escherichia coli DNA topoisomerase I mutants have compensatory mutations in DNA gyrase genes. Cell 31:43–51.

200. Dobrogosz, W. J. 1968. N-Acetylglucosamine assimilation in Escherichia coli and its relation to catabolite repression. J. Bacteriol. 95:585–591.

201. Dombrovsky, A. M., and T. I. Serzhantova. 1978. Identification of lac ⁺Salmonella. Zh. Mikrobiol. Epidemiol. Immunobiol. 5:48–53.

202. Doskocil, J. 1974. Inducible nucleoside permease in Escherichia coli. Biochem. Biophys. Res. Commun. 56:997–1003.

203. Doskocil, J. 1976. The role of thiol groups in nucleoside transport. Mol. Cell. Biochem. 10:137–143.

204. Doskocil, J., and A. Holy. 1974. Inhibition of nucleoside-binding sites by nucleoside analogues in Escherichia coli. Nucleic Acids Res. 1:491–502.

205. Doskocil, J., and A. Holy. 1977. Specificity of purine nucleoside phosphorylase from Escherichia coli. Collect. Czech. Chem. Commun. 42:370–383.

206. Doudoroff, M., W. Z. Hassid, E. W. Putnam, A. L. Putnam, A. L. Potter, and J. Lederberg. 1949. Direct utilization of maltose by Escherichia coli. J. Biol. Chem. 179:921–934.

207. Duguid, J. P., D. C. Old, and V. B. M. Hume. 1962. Transduction of fimbriation and rhamnose-fermentation characters in Salmonella typhimurium. Heredity 17:301–302.

208. Duplay, P., H. Bedouelle, A. Fowler, I. Zabin, W. Saurin, and M. Hofnung. 1984. Sequences of the malE gene and of its product, the maltose-binding protein of Escherichia coli K12. J. Biol. Chem. 259:10606–10613.

209. Dykhuizen, D., and D. Hartl. 1978. Transport by the lactose permease of Escherichia coli as the basis of lactose killing. J. Bacteriol. 135:876–882.

210. Eagon, R. G. 1961. Bacterial dissimilation of l-fucose and l-rhamnose. J. Bacteriol. 82:548–550.

211. Easterling, S. B., E. M. Johnson, J. A. Wohlhieter, and L. S. Baron. 1969. Nature of lactose-fermenting Salmonella strains obtained from clinical sources. J. Bacteriol. 100:35–41.

212. Edwards, P. R., and W. H. Ewing. 1972. Identification of Enterobacteriaceae, 3rd ed., p. 68. Burgess Publishing Co., Minneapolis.

213. Eggleston, L. V., and J. A. Krebs. 1959. Permeability of Escherichia coli to ribose and ribose nucleotides. Biochem. J. 73:264–270.

214. Eidels, L., P. D. Rick, N. P. Stimler, and M. J. Osborn. 1974. Transport of d-arabinose-5-phosphate and sedoheptulose-7-phosphate by the hexose phosphate transport system of Salmonella typhimurium. J. Bacteriol. 119:138–143.

215. Eisenstark, A., R. Eisenstark, and S. Cunningham. 1968. Genetic analysis of thymineless (thy) mutants of S. typhimurium. Genetics 58:493–506.

216. Elliott, J., and W. Arber. 1978. E. coli K-12 pel mutants, which block phage DNA injection, coincide with ptsM, which determines a component of a sugar transport system. Mol. Gen. Genet. 161:1–8.

217. Elvin, C. M., C. M. Hardy, and H. Rosenberg. 1985. P_i exchange mediated by the GlpT-dependent sn-glycerol-3-phosphate transport system in Escherichia coli. J. Bacteriol. 161:1054–1058.

218. Endermann, R., I. Hindennach, and U. Henning. 1978. Major proteins of the Escherichia coli outer cell envelope membrane. Preliminary characterization of the phage lambda receptor protein. FEBS Lett. 88:71–74.

219. Englesberg, E. 1961. Enzymatic characterization of 17 l-arabinose negative mutants of Escherichia coli. J. Bacteriol. 81:996–1006.

220. Englesberg, E., R. L. Anderson, R. Weinberg, N. Lee, P. Hoffe, G. Huttenbauer, and H. Boyer. 1962. l-Arabinose-sensitive, l-ribulose 5-phosphate 4-epimerase-deficient mutants of Escherichia coli. J. Bacteriol. 84:137–146.

221. Englesberg, E., and L. S. Baron. 1959. Mutation to l-rhamnose resistance and transduction to l-rhamnose utilization in Salmonella typhosa. J. Bacteriol. 78:675–686.

222. Englesberg, E., J. Irr, J. Power, and N. Lee. 1965. Positive control of enzyme synthesis by gene C in the l-arabinose system. J. Bacteriol. 90:946–957.

223. Englesberg, E., and G. Wilcox. 1974. Regulation: positive control. Annu. Rev. Genet. 8:219–242.

224. Enomoto, M., and B. A. D. Stocker. 1974. Transduction by phage P1Kc in Salmonella typhimurium. Virology 60:503–514.

224a. Erni, B., and B. Zanolari. 1985. The mannose-permease of the bacterial phosphotransferase system: gene cloning and purification of the enzyme II^Man/III^Man complex of Escherichia coli. J. Biol. Chem. 260:15495–15503.

225. Essenberg, R. C., and H. L. Kornberg. 1975. Energy coupling in the uptake of hexose phosphates by Escherichia coli. J. Biol. Chem. 250:939–945.

226. Essenberg, R. C., and H. L. Kornberg. 1977. Location of the gene specifying hexose phosphate transport (uhp) on the chromosome of Escherichia coli. J. Gen. Microbiol. 99:157–169.

227. Eze, M. O., and R. N. McElhaney. 1981. The effect of alterations in the fluidity and phase state of the membrane lipids on the passive permeation and facilitated diffusion of glycerol in Escherichia coli. J. Gen. Microbiol. 124:299–307.

228. Ezzell, J. W., and W. J. Dobrogosz. 1978. Cyclic AMP regulation of the hexose phosphate transport system in Escherichia coli. J. Bacteriol. 133:1047–1049.

229. Faik, P., H. L. Kornberg, and E. McEvoy-Bowe. 1971. Isolation and properties of E. coli mutants defective in 2-keto 3-deoxy-6-phosphogluconate aldolase activity. FEBS Lett. 19:225–228.

230. Falcao, D. P., L. R. Trabulsi, F. W. Hickman, and J. J. Farmer. 1975. Unusual Enterobacteriaceae: lactose-positive Salmonella typhimurium which is endemic in Sao Paulo, Brazil. J. Clin. Microbiol. 2:349–353.

231. Falkow, S., and L. S. Baron. 1962. Episomic element in a strain of Salmonella typhosa. J. Bacteriol. 84:581–589.

232. Fangman, W. L., and A. Novick. 1966. Mutation bacteria showing efficient utilization of thymidine. J. Bacteriol. 91:2390–2391.

233. Ferenci, T. 1980. The recognition of maltodextrins by Escherichia coli. Eur. J. Biochem. 108:631–636.

234. Ferenci, T., and W. Boos. 1980. The role of the Escherichia coli lambda receptor in the transport of maltose and maltodextrins. J. Supramol. Struct. 13:101–116.

235. Ferenci, T., W. Boos, M. Schwartz, and S. Szmelcman. 1977. Energy-coupling of the transport system of Escherichia coli dependent on maltose-binding protein. Eur. J. Biochem. 75:187–193.

236. Ferenci, T., and U. Klotz. 1978. Affinity chromatographic isolation of the periplasmic maltose-binding protein of Escherichia coli. FEBS Lett. 94:213–217.

237. Ferenci, T., and H. L. Kornberg. 1971. Pathway of fructose utilization by Escherichia coli. FEBS Lett. 13:127–130.

238. Ferenci, T., and H. L. Kornberg. 1971. Role of fructose-1,6-diphosphatase in fructose utilization by Escherichia coli. FEBS Lett. 14:360–363.

239. Ferenci, T., and H. L. Kornberg. 1973. The utilization of fructose by Escherichia coli. Properties of a mutant defective in fructose 1-phosphate kinase activity. Biochem. J. 132:341–347.

240. Ferenci, T., and H. L. Kornberg. 1974. The role of phosphotransferase synthesis of fructose 1-phosphate and fructose 6-phosphate in the growth of Escherichia coli on fructose. Proc. R. Soc. Lond. B Biol. Sci. 187:105–119.

241. Ferenci, T., H. L. Kornberg, and J. Smith. 1971. Isolation and properties of a regulatory mutant in the hexose phosphate transport system of Escherichia coli. FEBS Lett. 13:133–136.

242. Ferenci, T., and K.-S. Lee. 1982. Directed evolution of the lambda receptor of Escherichia coli through affinity chromatographic selection. J. Mol. Biol. 160:431–444.

243. Ferenci, T., M. Schwentorat, S. Ullrich, and J. Vilmart. 1980. Lambda receptor in the outer membrane of Escherichia coli as a binding protein for maltodextrins and starch polysaccharides. J. Bacteriol. 142:521–526.

244. Fischer, M., and S. A. Short. 1982. The cloning of the Escherichia coli K-12 deoxyribonucleoside operon. Gene 17:291–298.

245. Flagg, J. L., and T. H. Wilson. 1976. lacY mutant of Escherichia coli with altered physiology of lactose induction. J. Bacteriol. 128:701–707.

246. Fox, C. F., and E. P. Kennedy. 1967. A micro radiochemical assay for thiogalactoside transacetylase. Anal. Biochem. 18:286–294.

247. Fox, F., and G. Wilson. 1968. The role of phosphoenolpyruvate-dependent kinase system in beta-glucoside catabolism in Escherichia coli. Proc. Natl. Acad. Sci. USA 59:988–995.

248. Fradkin, J., and D. G. Fraenkel. 1971. 2-Keto-3-deoxygluconate 6-phosphate aldolase mutants of Escherichia coli. J. Bacteriol. 108:1277–1283.

249. Fraenkel, D. G. 1968. The phosphoenolpyruvate-initiated pathway of fructose metabolism in Escherichia coli. J. Biol. Chem. 243:6458–6463.

250. Fraenkel, D. G., and S. Banerjee. 1972. Deletion mapping of zwf, the gene for a constitutive enzyme glucose 6-phosphate dehydrogenase in Escherichia coli. Genetics 71:481–489.

251. Fraenkel, D. G., F. Falcos-Kelly, and B. L. Horecker. 1964. The utilization of glucose 6-phosphate by glucokinaseless and wild-type strains of Escherichia coli. Proc. Natl. Acad. Sci. USA 52:1207–1213.

252. Fraser, A. D. E., and H. Yamazaki. 1980. Characterization of an Escherichia coli mutant which utilizes glycerol in the absence of cyclic adenosine monophosphate. Can. J. Microbiol. 26:393–396.

253. Fraser, A. D. E., and H. Yamazaki. 1980. Mannose utilization in Escherichia coli requires cyclic AMP but not an exogenous inducer. Can. J. Microbiol. 26:1508–1511.

254. Freedberg, W. B., W. S. Kistler, and E. C. C. Lin. 1971. Lethal synthesis of methylglyoxal by Escherichia coli during unregulated glycerol metabolism. J. Bacteriol. 108:137–144.

255. Freedberg, W. B., and E. C. C. Lin. 1973. Three kinds of controls affecting the expression of the glp regulon in Escherichia coli. J. Bacteriol. 115:816–823.

256. Freundlieb, S., and W. Boos. 1982. Maltose transacetylase of Escherichia coli: a preliminary report. Ann. Inst. Pasteur Microbiol. 133A:181–189.

257. Friedberg, I. 1972. Localization of phosphoglucose isomerase in Escherichia coli and its relation to the induction of the hexose phosphate transport system. J. Bacteriol. 112:1201–1205.

258. Froshauer, S., and J. Beckwith. 1984. The nucleotide sequence of the gene for malF protein, an inner membrane component of the maltose transport system of Escherichia coli. Repeated DNA sequences are found in the malE-malF intercistronic region. J. Biol. Chem. 259:10896–10903.

259. Fukada, H., J. M. Sturtevant, and F. A. Quiocho. 1983. Thermodynamics of the binding of l-arabinose and of d-galactose to the l-arabinose-binding protein of Escherichia coli. J. Biol. Chem. 258:13193–13198.

260. Fukasawa, T., K. Jokura, and K. Kurahashi. 1962. A new enzymatic defect of galactose metabolism in Escherichia coli K12 mutants. Biochem. Biophys. Res. Commun. 7:121–125.

261. Fukasawa, T., K. Jokura, and K. Kurahashi. 1963. Mutations in Escherichia coli that affect uridine diphosphate glucose pyrophosphorylase activity and galactose fermentation. Biochim. Biophys. Acta 74:608–620.

262. Fukasawa, T., and H. Nikaido. 1959. Formation of "protoplasts" in mutant strains of Salmonella induced by galactose. Nature (London) 183:1131–1132.

263. Fukasawa, T., and H. Nikaido. 1959. Galactose-sensitive mutants of Salmonella. Nature (London) 184:1168–1169.

264. Fukasawa, T., and H. Nikaido. 1960. Formation of phage receptors induced by galactose in a galactose-sensitive mutant of Salmonella. Virology 11:508–510.

265. Fukasawa, T., and H. Nikaido. 1961. Galactose-sensitive mutants of Salmonella. II. Bacteriolysis induced by galactose. Biochim. Biophys. Acta 48:470–483.

266. Fukasawa, T., and H. Nikaido. 1961. Galactose mutants of Salmonella typhimurium. Genetics 46:1295–1303.

267. Galloway, D. R., and C. E. Furlong. 1977. The role of ribose-binding protein in transport and chemotaxis in Escherichia coli K12. Arch. Biochem. Biophys. 184:496–504.

268. Ganesan, A. K., and B. Rotman. 1965. Transport systems for galactose and galactosides in Escherichia coli. I. Genetic determination and regulation of the methylgalactoside permease. J. Mol. Biol. 16:42–50.

269. Garber, B. B., and J. S. Gots. 1980. Utilization of 2,6-diamino-purine by Salmonella typhimurium. J. Bacteriol. 143:864–871.

270. Garwin, J. L., and J. Beckwith. 1982. Secretion and processing of ribose-binding protein in Escherichia coli. J. Bacteriol. 149:789–792.

271. Ghalambor, M. A., and E. C. Heath. 1962. The metabolism of l-fucose. II. The enzymatic cleavage of l-fuculose-1-phosphate. J. Biol. Chem. 237:2427–2433.

272. Ghalambor, M. A., and E. C. Heath. 1966. l-Fuculokinase. Methods Enzymol. 9:461–464.

273. Ghalambor, M. A., and E. C. Heath. 1966. l-Fuculose 1-phosphate aldolase. Methods Enzymol. 9:538–542.

274. Ghangas, G. S., and D. B. Wilson. 1984. Isolation and characterization of the Salmonella typhimurium LT2 xylose regulon. J. Bacteriol. 157:158–164.

275. Ghosh, S., and S. Roseman. 1962. l-Glutamine-d-fructose 6-phosphate transamidase from Escherichia coli. Methods Enzymol. 5:414–422.

276. Gilliland, G. L., and F. A. Quiocho. 1981. Structure of the l-arabinose-binding protein from Escherichia coli at 2.4 Å resolution. J. Mol. Biol. 146:341–362.

277. Gilson, E., H. Nikaido, and M. Hofnung. 1982. Sequence of the malK gene in Escherichia coli K12. Nucleic Acids Res. 10:7449–7458.

278. Goldberg, M. E. 1969. Tertiary structure of Escherichia coli beta-d-galactosidase. J. Mol. Biol. 46:441–446.

279. Goldenbaum, P. E., and K. S. Farmer. 1980. uhp-Directed, glucose 6-phosphate membrane receptor in Escherichia coli. J. Bacteriol. 142:347–349.

280. Goldwasser, E. 1963. Sedimentation constant and molecular weight of thiogalactoside transacetylase. J. Biol. Chem. 238:3306.

281. Gonzalez, A. B. 1959. Lactose-fermenting Salmonella. J. Bacteriol. 91:1661–1662.

282. Green, M., and S. S. Cohen. 1956. Enzymatic conversion of l-fucose to l-fuculose. J. Biol. Chem. 219:557–568.

283. Greenfield, L., T. Boone, and G. Wilcox. 1978. DNA sequence of the araBAD promoter in Escherichia coli B/r. Proc. Natl. Acad. Sci. USA 75:4724–4728.

284. Grenier, F. C., E. B. Waygood, and M. H. Saier, Jr. 1985. Bacterial phospho-transferase system: regulation of mannitol enzyme II activity by sulfhydryl oxidation. Biochemistry 24:47–51.

285. Groarke, J. M., W. C. Mahoney, J. N. Hope, C. E. Furlong, F. T. Robb, H. Zalkin, and M. A. Hermodson. 1983. The amino acid sequence of d-ribose-binding protein from Escherichia coli K12. J. Biol. Chem. 258:12952–12956.

286. Gross, J., and E. Englesberg. 1959. Determination of the order of mutational sites governing l-arabinose utilization in Escherichia coli B/r by transduction with phage P1bt. Virology 9:314–331.

287. Guiso, N., and A. Ullmann. 1976. Expression and regulation of lactose genes carried by plasmids. J. Bacteriol. 127:691–697.

287a. Guth, A., R. Engel, and B. E. Tropp. 1980. Uptake of glycerol 3-phosphate and some of its analogs by the hexose phosphate transport system of Escherichia coli. J. Bacteriol. 143:538–539.

288. Gutnick, D., J. M. Calvo, T. Klopotowski, and B. N. Ames. 1969. Compounds which serve as the sole source of carbon or nitrogen for Salmonella typhimurium LT-2. J. Bacteriol. 100:215–219.

289. Gutowski, S. J., and H. Rosenberg. 1975. Succinate uptake and related proton movements in Escherichia coli K12. Biochem. J. 152:647–654.

290. Hacking, A. J., J. Aguilar, and E. C. C. Lin. 1978. Evolution of propanediol utilization in Escherichia coli: mutants with improved substrate-scavenging power. J. Bacteriol. 136:522–530.

291. Hacking, A. J., and E. C. C. Lin. 1976. Disruption of the fucose pathway as a consequence of genetic adaptation to propanediol as a carbon source in Escherichia coli. J. Bacteriol. 126:1166–1172.

292. Hacking, A. J., and E. C. C. Lin. 1977. Regulatory changes in the fucose system associated with the evolution of a catabolic pathway for propanediol in Escherichia coli. J. Bacteriol. 130:832–838.

293. Hagihira, H., T. H. Wilson, and E. C. C. Lin. 1963. Studies on the glucose-transport system in Escherichia coli with alpha-methylglucoside as substrate. Biochim. Biophys. Acta 78:505–515.

294. Hall, B. G. 1976. Experimental evolution of a new enzymatic function. Kinetic analysis of the ancestral (ebg °) and evolved (ebg ⁺0) enzymes. J. Mol. Biol. 107:71–84.

295. Hall, B. G. 1976. Methylgalactosidase activity: an alternative evolutionary destination for the ebgA° gene. J. Bacteriol. 126:536–538.

296. Hall, B. G. 1977. The number of mutations required to evolve a new lactase function in Escherichia coli. J. Bacteriol. 129:540–543.

297. Hall, B. G. 1978. Experimental evolution of a new enzymatic function. II. Evolution of multiple functions for EBG enzyme in E. coli. Genetics 89:453–465.

298. Hall, B. G. 1978. Regulation of newly evolved enzymes. IV. Directed evolution of the EBG repressor. Genetics 90:673–681.

299. Hall, B. G. 1981. Changes in the substrate specificities of an enzyme during directed evolution of new functions. Biochemistry 20:4042–4049.

300. Hall, B. G. 1982. Evolution of a regulated operon in the laboratory. Genetics 101:335–344.

301. Hall, B. G. 1982. Transgalactosylation activity of EBG betagalactosidase synthesizes allolactose from lactose. J. Bacteriol. 150:132–140.

302. Hall, B. G. 1982. Chromosomal mutation for citrate utilization by Escherichia coli K-12. J. Bacteriol. 151:269–273.

303. Hall, B. G., and N. D. Clarke. 1977. Regulation of newly evolved enzymes. III. Evolution of the ebg repressor during selection for enhanced lactase activity. Genetics 85:193–201.

304. Hall, B. G., and D. L. Hartl. 1974. Regulation of newly evolved enzymes. I. Selection of a novel lactase regulated by lactose in Escherichia coli. Genetics 76:391–400.

305. Hall, B. G., and D. L. Hartl. 1975. Regulation of newly evolved enzymes. II. The EBG repressor. Genetics 81:427–435.

306. Hall, B. G., and T. Zuzel. 1980. Evolution of a new enzymatic function by recombination within a gene. Proc. Natl. Acad. Sci. USA 77:3529–3533.

307. Hall, B. G., and T. Zuzel. 1980. The ebg operon consists of at least two genes. J. Bacteriol. 144:1208–1211.

308. Hammelburger, J. W., and G. A. Orr. 1983. Interaction of sn-glycerol 3-phosphorothioate with Escherichia coli: effect on cell growth and metabolism. J. Bacteriol. 156:789–799.

309. Hammer-Jespersen, K. 1983. Nucleoside catabolism, p. 203–258. In A. MunchPetersen (ed.), Metabolism of Nucleotides, Nucleosides and Nucleobases in Microorganisms. Academic Press, Inc. (London), Ltd., London.

310. Hammer-Jespersen, K., R. S. Buxton, and T. D. Hansen. 1980. A second purine nucleoside phosphorylase in Escherichia coli K-12. II. Properties of xanthosine phosphorylase and its induction by xanthosine. Mol. Gen. Genet. 179:341–348.

311. Hammer-Jespersen, K., and A. Munch-Petersen. 1970. Phosphodeoxyribomutase from Escherichia coli. Purification and some properties. Eur. J. Biochem. 17:397–407.

312. Hammer-Jespersen, K., and A. Munch-Petersen. 1973. Mutants of Escherichia coli unable to metabolize cytidine: isolation and characterization. Mol. Gen. Genet. 126:177–186.

313. Hammer-Jespersen, K., and A. Munch-Petersen. 1975. Multiple regulation of nucleoside catabolizing enzymes: regulation of the deo operon by the cytR and deoR gene products. Mol. Gen. Genet. 137:327–335.

314. Hammer-Jespersen, K., A. Munch-Petersen, P. Nygaard, and M. Schwartz. 1971. Induction of enzymes involved in the catabolism of deoxyribonucleosides and ribonucleosides in Escherichia coli K 12. Eur. J. Biochem. 19:533–538.

315. Hammer-Jespersen, K., and P. Nygaard. 1976. Multiple regulation of nucleoside catabolizing enzymes in Escherichia coli: effects of 3:5' cyclic AMP and CRP protein. Mol. Gen. Genet. 148:49–55.

316. Hanatani, M., H. Yazyu, S. S. Niiya, Y. Moriyama, H. Kanzawa, M. Futai, and T. Tsuchiya. 1984. Physical and genetic characterization of the melibiose operon and identification of the gene products in Escherichia coli. J. Biol. Chem. 259:1807–1812.

317. Hantke, K. 1976. Phage T6-colicin K receptor and nucleoside transport in Escherichia coli. FEBS Lett. 70:109–112.

318. Harayama, S., J. Bollinger, T. Iino, and G. L. Hazelbauer. 1983. Characterization of the mgl operon of Escherichia coli by transposon mutagenesis and molecular cloning. J. Bacteriol. 153:408–415.

319. Harrison, A. P., Jr. 1965. Thymine incorporation and metabolism by various classes of thymine-less bacteria. J. Gen. Microbiol. 41:321–333.

320. Hartl, D., and B. G. Hall. 1974. A second naturally occurring beta-galactosidase in Escherichia coli. Nature (London) 248:152–153.

321. Hartley, B. S. 1984. Experimental evolution of ribitol dehydrogenase, p. 23–54. In R. P. Mortlock (ed.), Microorganisms as Model Systems for Studying Evolution. Plenum Publishing Corp., New York.

322. Hartley, B. S. 1984. The structure and control of the pentitol operons, p. 55–107. In R. P. Mortlock (ed.), Microorganisms as Model Systems for Studying Evolution. Plenum Publishing Corp., New York.

323. Häselbarth, V., G. V. Schulz, and H. Schwinn. 1971. Untersuchungen über Amylomaltase. II. Molekulare Konstanten und Wirkungsweise des Enzymes. Biochim. Biophys. Acta 227:296–312.

324. Hattman, S., and T. Fukasawa. 1963. Host-induced modification of T-even phages due to defective glucosylation of their DNA. Proc. Natl. Acad. Sci. USA 50:297–300.

325. Hayashi, S.-I., J. P. Koch, and E. C. C. Lin. 1964. Active transport of l-alpha-glycerophosphate in Escherichia coli. J. Biol. Chem. 239:3098–3105.

326. Hayashi, S.-I., and E. C. C. Lin. 1965. Capture of glycerol by cells of Escherichia coli. Biochim. Biophys. Acta 94:479–487.

327. Hayashi, S.-I., and E. C. C. Lin. 1965. Product induction of glycerol kinase in Escherichia coli. J. Mol. Biol. 14:515–521.

328. Hayashi, S.-I., and E. C. C. Lin. 1967. Purification and properties of glycerol kinase from Escherichia coli. J. Biol. Chem. 242:1030–1035.

329. Hazelbauer, G. L. 1975. The maltose chemoreceptor of Escherichia coli. J. Bacteriol. 122:206–214.

330. Hazelbauer, G. L. 1975. Role of the receptor for bacteriophage lambda in the functioning of the maltose chemoreceptor of Escherichia coli. J. Bacteriol. 124:119–126.

331. Hazelbauer, G. L., and J. Adler. 1971. Role of galactose-binding protein in chemotaxis of Escherichia coli toward galactose. Nature (London) New Biol. 230:101–104.

332. Heald, K., and C. Long. 1955. Studies involving enzymic phosphorylation. 3. The phosphorylation of d-ribose by extracts of Escherichia coli. Biochem. J. 59:316–322.

333. Heath, E. C., and M. A. Ghalambor. 1962. The metabolism of l-fucose. I. The purification and properties of l-fuculose kinase. J. Biol. Chem. 237:2423–2426.

334. Heller, K. B., E. C. C. Lin, and T. H. Wilson. 1980. Substrate specificity and transport properties of the glycerol facilitator of Escherichia coli. J. Bacteriol. 144:274–278.

335. Heller, K. B., and T. H. Wilson. 1979. Sucrose transport by the Escherichia coli lactose carrier. J. Bacteriol. 140:395–399.

336. Henderson, P. J. F., R. A. Giddens, and M. C. Jones-Mortimer. 1977. Transport of galactose, glucose and their molecular analogues by Escherichia coli K12. Biochem. J. 162:309–320.

337. Hendlin, D., E. O. Stapley, M. Jackson, H. Wallick, A. K. Miller, F. J. Wolf, T. W. Miller, L. Chaiet, F. M. Kahan, E. L. Foltz, H. B. Woodruff, J. M. Mata, S. Hernandez, and S. Mochales. 1969. Phosphonomycin, a new antibiotic produced by strains of Streptomyces. Science 166:122–123.

338. Hengge, R., and W. Boos. 1983. Maltose and lactose transport in Escherichia coli. Examples of two different types of concentrative transport systems. Biochim. Biophys. Acta 737:443–478.

339. Hengge, R., T. J. Larson, and W. Boos. 1983. sn-Glycerol-3-phosphate transport in Salmonella typhimurium. J. Bacteriol. 155:186–195.

340. Hennen, P. E., H. B. Carter, and W. D. Nunn. 1978. Changes in macromolecular synthesis and nucleoside triphosphate levels during glycerol-induced growth stasis of Escherichia coli. J. Bacteriol. 136:929–935.

341. Heppel, L. A. 1969. The effect of osmotic shock on release of bacterial proteins and an active transport. J. Gen. Physiol. 54:95–109.

342. Herbert, A. A., and J. R. Guest. 1971. Two mutations affecting utilization of C₄-dicarboxylic acids by Escherichia coli. J. Gen. Microbiol. 63:151–162.

343. Herzenberg, L. A. 1961. Isolation and identification of derivatives formed in the course of intracellular accumulation of thiogalactosides by Escherichia coli. Arch. Biochem. Biophys. 93:314–315.

344. Hickman, J., and G. Ashwell. 1960. Uronic acid metabolism in bacteria. II. Purification and properties of d-altronic acid and d-mannonic acid dehydrogenases in Escherichia coli. J. Biol. Chem. 235:1566–1570.

345. Hill, C. W., and H. Echols. 1966. Properties of a mutant blocked in inducibility of messenger RNA for the galactose operon. J. Mol. Biol. 19:38–51.

346. Hochstadt-Ozer, J. 1972. The regulation of purine utilization in bacteria. IV. Roles of membrane-localized and pericytoplasmic enzymes in the mechanism of purine nucleoside transport across isolated Escherichia coli membranes. J. Biol. Chem. 247:2419–2426.

347. Hochstadt-Ozer, J., and E. R. Stadtman. 1971. The regulation of purine utilization in bacteria. II. Adenine phosphoribosyltransferase in isolated membrane preparations and its role in transport of adenine across the membrane. J. Biol. Chem. 246:5304–5311.

348. Hoffee, P., P. Snyder, C. Sushak, and P. Jargiello. 1974. Deoxyribose-5-P-aldolase: subunit structure and composition of active site lysine region. Arch. Biochem. Biophys. 164:736–742.

349. Hoffee, P. A. 1968. 2-Deoxyribose gene-enzyme complex in Salmonella typhimurium. I. Isolation and enzymatic characterization of 2-deoxyribose-negative mutants. J. Bacteriol. 95:449–457.

350. Hoffee, P. A. 1968. 2-Deoxyribose-5-phosphate aldolase of Salmonella typhimurium. Purification and properties. Arch. Biochem. Biophys. 126:795–802.

351. Hoffee, P. A., and J. Blank. 1978. Thymidine phosphorylase from Salmonella typhimurium. Methods Enzymol. 51:437–442.

352. Hoffee, P. A., and B. C. Robertson. 1969. 2-Deoxyribose gene-enzyme complex in Salmonella typhimurium: regulation of phosphodeoxyribomutase. J. Bacteriol. 97:1386–1396.

353. Hoffman, C. E., and J. P. Lampen. 1952. Products of deoxyribose degradation by Escherichia coli. J. Biol. Chem. 198:885–893.

354. Hoffmeyer, J., and J. Neuhard. 1971. Metabolism of exogenous purine bases and nucleosides by Salmonella typhimurium. J. Bacteriol. 106:14–24.

355. Hofnung, M. (ed.). 1982. The maltose system as a tool in molecular biology. Ann. Inst. Pasteur Microbiol. 133A:5–273.

356. Hofnung, M., A. Jezierska, and C. Braun-Breton. 1976. lamB mutations in E. coli K12: growth of lambda host range mutants and effects of nonsense suppressors. Mol. Gen. Genet. 145:207–213.

357. Hogg, R., and M. A. Hermodson. 1977. Amino acid sequence of the l-arabinose-binding protein from Escherichia coli B/r. J. Biol. Chem. 252:5135–5141.

358. Hogg, R. W. 1977. l-Arabinose-transport and the l-arabinose binding protein of Escherichia coli. J. Supramol. Struct. 6:411–417.

359. Hogg, R. W., and E. Englesberg. 1969. l-Arabinose binding protein from Escherichia coli. J. Bacteriol. 100:423–432.

360. Hogg, R. W., H. Isihara, M. A. Hermodson, D. Koshland, Jr., J. W. Jacobs, and R. A. Bradshaw. 1977. A comparison of the amino-terminal sequences of several carbohydrate binding proteins from Escherichia coli and Salmonella typhimurium. FEBS Lett. 80:377–379.

361. Holmes, R. P., and R. R. Russell. 1972. Mutations affecting amino sugar metabolism in Escherichia coli K-12. J. Bacteriol. 111:290–291.

362. Horecker, B. L., J. Thomas, and J. Monod. 1960. Galactose transport in Escherichia coli. I. General properties as studied with a galactokinaseless mutant. J. Biol. Chem. 235:1580–1585.

363. Horecker, B. L., J. Thomas, and J. Monod. 1960. Galactose transport in Escherichia coli. II. Characteristics of the exit process. J. Biol. Chem. 235:1586–1590.

364. Horiuchi, T., J. Tomizawa, and A. Novick. 1962. Isolation and properties of bacteria capable of high rates of beta-galactosidase synthesis. Biochim. Biophys. Acta 55:152–163.

365. Horwitz, A. H., L. Heffernan, C. Morandi, J.-H. Lee, J. Timko, and G. Wilcox. 1981. DNA sequence of the araBAD-araC controlling region in Salmonella typhimurium LT2. Gene 14:309–319.

366. Hosono, H., and S. Kuno. 1973. The purification and properties of cytidine deaminase from Escherichia coli. J. Biochem. 74:797–803.

367. Hsie, A. W., H. V. Rickenberg, D. W. Schulz, and W. M. Kirsch. 1969. Steady-state concentrations of glucose-6-phosphate, 6-phosphogluconate, and reduced nicotinamide adenine dinucleotide phosphate in strains of Escherichia coli sensitive and resistant to catabolite repression. J. Bacteriol. 98:1407–1408.

368. Huber, R. E., G. Kurz, and K. Wallenfels. 1976. A quantitation of the factors which affect the hydrolase and transgalactosylase activities of beta-galactosidase (E. coli) on lactose. Biochemistry 15:1994–2001.

369. Hugouvieux-Cotte-Pattat, N., and J. Robert-Baudouy. 1981. Isolation of fusions between the lac genes and several genes of the exu regulon: analysis of their regulation, determination of the transcription direction of the uxaC-uxaA operon, in Escherichia coli K-12. Mol. Gen. Genet. 182:279–287.

370. Hugouvieux-Cotte-Pattat, N., and J. Robert-Baudouy. 1982. Determination of the transcription direction of the exuT gene in Escherichia coli K-12: divergent transcription of the exuT-uxaCA operons. J. Bacteriol. 151:480–484.

371. Hugouvieux-Cotte-Pattat, N., and J. Robert-Baudouy. 1982. Regulation and transcription direction of exuR, a self-regulated repressor in Escherichia coli K-12. J. Mol. Biol. 156:221–228.

372. Iida, A., S. Harayama, T. Iino, and G. L. Hazelbauer. 1984. Molecular cloning and characterization of genes required for ribose transport and utilization in Escherichia coli K-12. J. Bacteriol. 158:674–682.

373. Imada, A., and S. Igarasi. 1967. Ribosyl and deoxyribosyl transfer by bacterial enzyme systems. J. Bacteriol. 94:1551–1559.

374. Imada, A., Y. Nozaki, F. Kawashima, and M. Yonida. 1977. Regulation of glucosamine utilization in Staphylococcus aureus and Escherichia coli. J. Gen. Microbiol. 100:329–337.

375. Imai, K., T. Iijima, and T. Hasegawa. 1973. Transport of tricarboxylic acids in Salmonella typhimurium. J. Bacteriol. 114:961–965.

376. Irani, M., L. Orosz, S. Busby, T. Taniguchi, and S. Adhya. 1983. Cyclic AMP-dependent constitutive expression of gal operon: use of repressor titration to isolate operator mutations. Proc. Natl. Acad. Sci. USA 80:4775–4779.

377. Irani, M. H., L. Orosz, and S. Adhya. 1983. A control element within a structural gene: the gal operon of Escherichia coli. Cell 32:783–788.

377a. Ishiguro, N., K. Hirose, M. Asagi, and G. Sato. 1981. Incompatibility of citrate utilization plasmids isolated from Escherichia coli. J. Gen. Microbiol. 123:193–196.

377b. Ishiguro, N., C. Oka, Y. Hanazawa, and G. Sato. 1979. Plasmids in Escherichia coli controlling citrate-utilizing ability. Appl. Environ. Microbiol. 38:956–964.

377c. Ishiguro, N., C. Oka, Y. Hanazawa, and G. Sato. 1980. Isolation of citrate utilization plasmid from a bovine Salmonella typhimurium strain. Microbiol. Immunol. 24:757–760.

377d. Ishiguro, N., C. Oka, and G. Sato. 1978. Isolation of citrate-positive variants of Escherichia coli from domestic pigeons, pigs, cattle, and horses. Appl. Environ. Microbiol. 36:217–222.

377e. Ishiguro, N., and G. Sato. 1979. The distribution of plasmids determining citrate utilization in citrate-positive variants of Escherichia coli from humans, domestic animals, feral birds and environments. J. Hyg. 83:331–344.

377f. Ishiguro, N., G. Sato, C. Sasakawa, H. Danbara, and M. Yoshikawa. 1982. Identification of citrate utilization transposon Tn3411 from a naturally occurring citrate utilization plasmid. J. Bacteriol. 149:961–968.

378. Ishii, J. N., Y. Okajima, and T. Nakae. 1981. Characterization of lamB protein from the outer membrane of Escherichia coli that forms diffusion pores selective for maltose-maltodextrins. FEBS Lett. 134:217–220.

379. Isono, K., and M. Kitakawa. 1978. Cluster of ribosomal protein genes in Escherichia coli containing genes for proteins S6, S18, and L9. Proc. Natl. Acad. Sci. USA 75:6163–6167.

380. Jacobson, G. R., D. M. Kelly, and D. R. Finlay. 1983. The intramembrane topography of the mannitol-specific enzyme II of the Escherichia coli phosphotransferase system. J. Biol. Chem. 258:2955–2959.

381. Jacobson, G. R., C. A. Lee, J. E. Leonard, and M. H. Saier, Jr. 1983. Mannitol-specific enzyme II of the bacterial phosphotransferase system. I. Properties of the purified permease. J. Biol. Chem. 258:10748–10756.

382. Jacobson, G. R., C. A. Lee, and M. H. Saier, Jr. 1979. Purification of the mannitol-specific enzyme II of the Escherichia coli phosphoenolpyruvate:sugar phosphotransferase system. J. Biol. Chem. 254:249–252.

383. Jacobson, G. R., L. E. Tanney, D. M. Kelly, K. B. Palman, and S. B. Corn. 1983. Substrate and phospholipid specificity of the purified mannitol permease of Escherichia coli. J. Cell Biochem. 23:231–240.

384. Janion, C. 1977. On the ability of Salmonella typhimurium cells to form deoxycytidine nucleotides. Mol. Gen. Genet. 153:179–183.

385. Jargiello, P. 1976. Simultaneous selection of mutants in gluconeogenesis and nucleoside catabolism in Salmonella typhimurium. Biochim. Biophys. Acta 444:321–325.

386. Jargiello, P., and P. Hoffee. 1972. Orientation of the deo genes and the serB locus in Salmonella typhimurium. J. Bacteriol. 111:296–297.

387. Jargiello, P., M. D. Stern, and P. Hoffee. 1974. 2-Deoxyribose 5-phosphate aldolase: genetic analyses of structure. J. Mol. Biol. 88:671–691.

388. Jargiello, P., C. Sushak, and P. Hoffee. 1976. 2-Deoxyribose 5-phosphate aldolase: isolation and characterization of proteins genetically modified in the active site region. Arch. Biochem. Biophys. 177:630–641.

389. Jensen, K. F. 1976. Purine-nucleoside phosphorylase from Salmonella typhimurium and Escherichia coli. Initial velocity kinetics, ligand binding, and reaction mechanism. Eur. J. Biochem. 61:377–386.

390. Jensen, K. F., and P. Nygaard. 1975. Purine nucleoside phosphorylase from Escherichia coli and Salmonella typhimurium. Purification and some properties. Eur. J. Biochem. 51:253–265.

391. Jensen, P., C. Parkes, and D. Berkowitz. 1972. Mannitol sensitivity. J. Bacteriol. 111:351–355.

392. Jergensen, P., J. Collins, and P. Valentin-Hansen. 1977. On the structure of the deo operon of Escherichia coli. Mol. Gen. Genet. 155:93–102.

393. Jimeno-Abendano, J., and A. Kepes. 1973. Sensitization of d-glucuronic acid transport system of Escherichia coli to protein group reagents in presence of substrate or absence of energy source. Biochem. Biophys. Res. Commun. 54:1342–1346.

394. Jin, R. Z., and E. C. C. Lin. 1984. An inducible phosphoenolpyruvate: dihydroxyacetone phosphotransferase system in Escherichia coli. J. Gen. Microbiol. 130:83–88.

395. Jin, R. Z., J. C.-T. Tang, and E. C. C. Lin. 1983. Experimental evolution of a novel pathway for glycerol dissimilation in Escherichia coli. J. Mol. Evol. 19:429–436.

396. Jobe, A., and S. Bourgeois. 1972. lac repressor-operator interaction. VI. The natural inducer of the lac operon. J. Mol. Biol. 69:397–408.

397. Jochimsen, B., P. Nygaard, and T. Vestergaard. 1975. Location on the chromosome of Escherichia coli of genes governing purine metabolism. Adenosine deaminase (add), guanosine kinase (gsk) and hypoxanthine phosphoribosyltransferase (hpt). Mol. Gen. Genet. 143:85–91.

398. Johnston, K. G., and R. T. Jones. 1976. Salmonellosis in calves due to lactose fermenting Salmonella typhimurium. Vet. Rec. 98:276–278.

399. Jones-Mortimer, M. C., and H. L. Kornberg. 1974. Genetical analysis of fructose utilization by Escherichia coli. Proc. R. Soc. Lond. B Biol. Sci. 187:121–131.

400. Jones-Mortimer, M. C., and H. L. Kornberg. 1976. Order of genes adjacent to ptsX on the E. coli genome. Proc. R. Soc. Lond. B Biol. Sci. 193:313–315.

401. Jones-Mortimer, M. C., and H. L. Kornberg. 1976. Uptake of fructose by the sorbitol phosphotransferase of Escherichia coli K12. J. Gen. Microbiol. 96:383–391.

402. Jones-Mortimer, M. C., and H. L. Kornberg. 1980. Amino-sugar transport systems of Escherichia coli K12. J. Gen. Microbiol. 117:369–376.

403. Jonsen, J., and S. Laland. 1957. Adaptation of E. coli to 2-deoxy-d-ribose. Acta Chem. Scand. 11:1095–1096.

404. Jonsen, J., S. Laland, and A. Strand. 1959. Degradation of deoxyribose by E. coli. Studies with cell-free extract and isolation of 2-deoxy-d-ribose 5-phosphate. Biochim. Biophys. Acta 32:117–123.

405. Jordan, E., and M. B. Yarmolinsky. 1963. Control of internal induction of galactose pathway enzymes in an Escherichia coli mutant. J. Gen. Microbiol. 30:357–364.

406. Jordan, E., M. B. Yarmolinsky, and H. M. Kalckar. 1962. Control of inducibility of enzymes of the galactose sequence in Escherichia coli. Proc. Natl. Acad. Sci. USA 48:32–40.

407. Jørgensen, P., J. Collins, and P. Valentin-Hansen. 1977. On the structure of the deo operon of Escherichia coli. Mol. Gen. Genet. 155:93–102.

408. Josephsen, J., and K. Hammer-Jespersen. 1981. Fusion of the lac genes to the promoter for the cytidine deaminase gene of Escherichia coli K-12. Mol. Gen. Genet. 182:154–158.

409. Josephsen, J., K. Hammer-Jespersen, and T. D. Hansen. 1983. Mapping of the gene for cytidine deaminase (cdd) in Escherichia coli K-12. J. Bacteriol. 154:72–75.

410. Kaback, H. R. 1983. The lac carrier protein in Escherichia coli. J. Membr. Biol. 76:95–112.

411. Kadner, R. J. 1973. Genetic control of the transport of hexose phosphates in Escherichia coli: mapping of the uhp locus. J. Bacteriol. 116:764–770.

412. Kadner, R. J., and D. M. Shattuck-Eidens. 1983. Genetic control of the hexose phosphate transport system of Escherichia coli: mapping of deletion and insertion mutations in the uhp region. J. Bacteriol. 155:1052–1061.

413. Kadner, R. J., and H. H. Winkler. 1973. Isolation and characterization of mutations affecting the transport of hexose phosphates in Escherichia coli. J. Bacteriol. 113:895–900.

414. Kahan, F. M., J. S. Kahan, P. J. Cassidy, and H. Kropp. 1974. The mechanism of action of fosfomycin (phosphonomycin). Ann. N.Y. Acad. Sci. 235:364–386.

415. Kalckar, H. M. 1958. Uridine diphospho galactose: metabolism, enzymology and biology. Adv. Enzymol. 20:111–134.

416. Kalckar, H. M. 1965. Galactose metabolism and cell "sociology." Science 150:305–313.

417. Kalckar, H. M. 1971. The periplasmic galactose binding protein of Escherichia coli. Science 174:557–565.

418. Kalckar, H. M. 1976. The periplasmic galactose receptor protein of Escherichia coli in relation to galactose chemotaxis. Biochimie 58:81–85.

419. Kalckar, H. M., K. Kurahashi, and E. Jordan. 1959. Hereditary defects in galactose metabolism in Escherichia coli mutants. I. Determination of enzyme activities. Proc. Natl. Acad. Sci. USA 45:1776–1786.

420. Karlstrøm, O. 1968. Mutants of Escherichia coli defective in ribonucleoside and deoxyribonucleoside catabolism. J. Bacteriol. 95:1069–1077.

421. Kauffmann, F. 1966. The Bacteriology of Enterobacteriaceae; Collected Studies of the Author and his Co-Workers, 3rd ed. The Williams & Wilkins Co., Baltimore.

422. Kay, W. W., and M. J. Cameron. 1978. Citrate transport in Salmonella typhimurium. Arch. Biochem. Biophys. 190:270–280.

423. Kay, W. W., and M. J. Cameron. 1978. Transport of C₄-dicarboxylic acids in Salmonella typhimurium. Arch. Biochem. Biophys. 190:281–289.

424. Kay, W. W., and H. L. Kornberg. 1969. Genetic control of the uptake of C₄-dicarboxylic acids by Escherichia coli. FEBS Lett. 3:93–96.

425. Kay, W. W., and H. L. Kornberg. 1971. The uptake of C₄-dicarboxylic acids by Escherichia coli. Eur. J. Biochem. 18:274–281.

425a. Kay, W. W., J. M. Somers, G. D. Sweet, and K. A. Widenhorn. 1984. Tricarboxylate transport systems: the tct operon in Salmonella typhimurium, p. 34–37. In L. Leive and D. Schlessinger (ed.), Microbiology—1984. American Society for Microbiology, Washington, D.C.

426. Kellerman, O., and S. Szmelcman. 1974. Active transport of maltose in Escherichia coli K-12: involvement of a "periplasmic" maltose binding protein. Eur. J. Biochem. 47:139–149.

427. Kelley, J. J., and E. E. Dekker. 1984. d-1-Amino-2-propanol:NAD⁺ oxidoreductase. J. Biol. Chem. 259:2124–2129.

428. Kelley, J. J., and E. E. Dekker. 1985. Identity of Escherichia coli d-1-amino-2-propanol:NAD⁺ oxidoreductase with E. coli glycerol dehydrogenase but not with Neisseria gonorrhoeae 1,2-propanediol:NAD⁺ oxidoreductase. J. Bacteriol. 162:170–175.

429. Kemper, J. 1974. Gene order and co-transduction in the leu-ara-fol-pyr-A region of the Salmonella typhimurium linkage map. J. Bacteriol. 117:94–99.

430. Kerwar, G. K., A. S. Gordon, and H. R. Kaback. 1972. Mechanisms of active transport in isolated membrane vesicles. IV. Galactose transport by isolated membrane vesicles from Escherichia coli. J. Biol. Chem. 247:291–297.

431. Kistler, W. S., C. A. Hirsch, N. R. Cozzarelli, and E. C. C. Lin. 1969. Second pyridine nucleotide-independent l-alpha-glycerophosphate dehydrogenase in Escherichia coli K-12. J. Bacteriol. 100:1133–1135.

432. Kistler, W. S., and E. C. C. Lin. 1971. Anaerobic l-alpha-glycerophosphate dehydrogenase of Escherichia coli: its genetic locus and its physiological role. J. Bacteriol. 108:1224–1234.

433. Kistler, W. S., and E. C. C. Lin. 1972. Purification and properties of the flavine-stimulated anaerobic l-alpha-glycerophosphate dehydrogenase of Escherichia coli. J. Bacteriol. 112:539–547.

434. Koch, A. L., and W. A. Lamont. 1956. The metabolism of methylpurines by Escherichia coli. J. Biol. Chem. 219:189–201.

435. Koch, A. L., and G. Vallee. 1959. The properties of adenosine deaminase and adenosine nucleoside phosphorylase in extracts of Escherichia coli. J. Biol. Chem. 234:1213–1218.

436. Koch, J. P., S.-I. Hayashi, and E. C. C. Lin. 1964. The control of dissimilation of glycerol and l-alpha-glycerophosphate in Escherichia coli. J. Biol. Chem. 239:3106–3108.

437. Kolodrubetz, D., and R. Schleif. 1981. Regulation of the l-arabinose transport operons in Escherichia coli. J. Mol. Biol. 151:215–227.

438. Kolodrubetz, D., and R. Schleif. 1981. l-Arabinose transport systems in Escherichia coli K-12. J. Bacteriol. 148:472–479.

439. Komatsu, Y. 1971. Mechanism of action of showdomycin. IV. Interactions between the mechanisms for transport of showdomycin and various nucleosides in Escherichia coli. Agric. Biol. Chem. 35:1328–1339.

440. Komatsu, Y. 1971. Mechanism of action of showdomycin. V. Reduced ability of showdomycin-resistant mutants of Escherichia coli K-12 to take up showdomycin and nucleosides. J. Antibiot. 24:876–883.

441. Komatsu, Y. 1973. Adenosine uptake by isolated membrane vesicles from Escherichia coli K-12. Biochim. Biophys. Acta 330:206–221.

442. Komatsu, Y. 1981. A highly showdomycin-resistant mutant of Escherichia coli K-12 with altered nucleoside transport characteristics. Agric. Biol. Chem. 45:609–618.

443. Komatsu, Y., and K. Tanaka. 1970. Mechanism of action of showdomycin. II. Effect of showdomycin on the synthesis of deoxyribonucleic acid in Escherichia coli. Agric. Biol. Chem. 34:891–899.

444. Komatsu, Y., and K. Tanaka. 1972. A showdomycin-resistant mutant of Escherichia coli K-12 with altered nucleoside transport character. Biochim. Biophys. Acta 288:390–403.

445. Komatsu, Y., and K. Tanaka. 1973. Deoxycytidine uptake by isolated membrane vesicles from Escherichia coli K 12. Biochim. Biophys. Acta 311:496–506.

446. Konings, W. N., and H. R. Kaback. 1973. Anaerobic transport in Escherichia coli membrane vesicles. Proc. Natl. Acad. Sci. USA 70:3376–3381.

447. Koppel, J. L., C. J. Porter, and B. F. Crocker. 1953. The mechanism of the synthesis of enzymes. I. Development of a system for studying this phenomenon. J. Gen. Physiol. 36:703–722.

448. Kornberg, H. L., and M. C. Jones-Mortimer. 1975. PtsX: a gene involved in the uptake of glucose and fructose by Escherichia coli. FEBS Lett. 51:1–4.

449. Kornberg, H. L., and R. E. Reeves. 1972. Correlation between hexose transport and phosphotransferase activity in Escherichia coli. Biochem. J. 126:1241–1243.

450. Kornberg, H. L., and R. E. Reeves. 1972. Inducible phosphoenolpyruvate-dependent hexose phosphotransferase activities in Escherichia coli. Biochem. J. 128:1339–1344.

451. Kornberg, H. L., and J. Smith. 1969. Genetic control of hexose phosphate uptake by Escherichia coli. Nature (London) 224:1261–1262.

452. Koser, S. A. 1923. Utilization of the salts of organic acids by colon-aerogenes group. J. Bacteriol. 8:493–520.

453. Kosiba, B. E., and R. Schleif. 1982. Arabinose-inducible promoter from Escherichia coli. Its cloning from chromosomal DNA, identification as the araFG promoter and sequence. J. Mol. Biol. 156:53–66.

454. Krenitzky, T. A. 1976. Uridine phosphorylase from Escherichia coli. Kinetic properties and mechanism. Biochim. Biophys. Acta 429:352–358.

455. Krieger-Brauer, H. J., and V. Braun. 1980. Functions related to the receptor protein specified by the tsx gene of Escherichia coli. Arch. Microbiol. 124:233–242.

456. Kuby, S. A., and H. A. Lardy. 1953. Purification and kinetics of β-galactosidase from Escherichia coli, strain K-12. J. Am. Chem. Soc. 75:890–896.

457. Kumar, S. 1976. Properties of adenyl cyclase and receptor cyclic adenosine 3', 5'-monophosphate protein-deficient mutants of Escherichia coli. J. Bacteriol. 125:545–555.

458. Kundig, W., S. Ghosh, and S. Roseman. 1964. Phosphate bound to histidine in a protein as an intermediate in a novel phosphotransferase system. Proc. Natl. Acad. Sci. USA 52:1067–1074.

459. Kung, H.-F., and U. Henning. 1972. Limiting availability of binding sites for dehydrogenases on the cell membrane of Escherichia coli. Proc. Natl. Acad. Sci. USA 69:925–929.

460. Kunz, L. J., and W. H. Ewing. 1965. Laboratory infection with a lactose-fermenting strain of Salmonella typhimurium. J. Bacteriol. 89:1629.

461. Kurahashi, K. 1957. Enzyme formation in galactose-negative mutants of Escherichia coli. Science 125:114–116.

462. Kurahashi, K., and A. Sugimura. 1960. Purification and properties of galactose 1-phosphate uridyl transferase from Escherichia coli. J. Biol. Chem. 235:940–946.

463. Kurahashi, K., and A. J. Wahba. 1958. Interference with growth of certain Escherichia coli mutants by galactose. Biochim. Biophys. Acta 30:298–302.

464. Kuritzkes, D. R., X.-Y. Zhang, and E. C. C. Lin. 1984. Use of phi(glp-lac) in studies of respiratory regulation of the Escherichia coli anaerobic sn-glycerol-3-phosphate dehydrogenase genes (glpAB). J. Bacteriol. 157:591–598.

465. Kusch, M., and T. H. Wilson. 1973. Defective lactose utilization by a mutant of Escherichia coli energy-uncoupled for lactose transport. Biochim. Biophys. Acta 311:109–122.

466. Lagarde, A. E. 1977. Evidence for an electrogenic 3-deoxy-2-keto-d-gluconate-proton co-transport driven by the protonmotive force in Escherichia coli K-12. Biochem. J. 168:211–221.

467. Lagarde, A. E., and B. A. Haddock. 1977. Proton uptake linked to the 3-deoxy-2-oxo-d-gluconate-transport system of Escherichia coli. Biochem. J. 162:183–187.

468. Lagarde, A., J. Pouyssegur, and F. Stoeber. 1972. Accumulation du d-glucuronate par le système de transport du 2-ceto-3-desoxy-d-gluconate chez Escherichia coli K 12. C.R. Acad. Sci. Ser. D 275:1831–1834.

469. Lagarde, A., J. Pouyssegur, and F. Stoeber. 1973. A transport system for 2-keto-3-deoxy-d-gluconate uptake in Escherichia coli K 12. Biochemical and physiological studies in whole cells. Eur. J. Biochem. 36:328–341.

470. Lagarde, A., and F. Stoeber. 1974. Transport of 2-keto-3-deoxy-d-gluconate in isolated membrane vesicles of Escherichia coli K 12. Eur. J. Biochem. 43:197–208.

471. Lagarde, A. E., and F. R. Stoeber. 1975. The energy-coupling controlled efflux of 2-keto-3-deoxy-d-gluconate in Escherichia coli K-12. Eur. J. Biochem. 55:343–354.

472. Lagarde, A. E., and F. R. Stoeber. 1977. Escherichia coli K-12 structural kdgT mutants exhibiting thermosensitive 2-keto-3-deoxy-d-gluconate uptake. J. Bacteriol. 129:606–615.

473. Lam, V. M. S., K. R. Daruwalla, P. J. F. Henderson, and M. C. Jones-Mortimer. 1980. Proton-linked d-xylose transport in Escherichia coli. J. Bacteriol. 143:396–402.

473a. Lara, F. J. S., and J. L. Stokes. 1952. Oxidation of citrate by Escherichia coli. J. Bacteriol. 63:415–420.

474. Larson, T. J., M. Ehrmann, and W. Boos. 1983. Periplasmic glycero-phosphodiester phosphodiesterase of Escherichia coli, a new enzyme of the glp regulon. J. Biol. Chem. 258:5428–5432.

475. Larson, T. J., G. Schumacher, and W. Boos. 1982. Identification of the glpT-encoded sn-glycerol-3-phosphate permease of Escherichia coli, an oligomeric integral membrane protein. J. Bacteriol. 152:1008–1021.

476. Lawlis, V. B., M. S. Dennis, E. Y. Chen, D. H. Smith, and D. J. Henner. 1984. Cloning and sequencing of the xylose isomerase and xylulose kinase genes of Escherichia coli. Appl. Environ. Microbiol. 47:15–21.

477. LeBlanc, D. J., and R. P. Mortlock. 1971. Metabolism of d-arabinose: origin of a d-ribulokinase activity in Escherichia coli. J. Bacteriol. 106:82–89.

478. LeBlanc, D. J., and R. P. Mortlock. 1971. Metabolism of d-arabinose: a new pathway in Escherichia coli. J Bacteriol. 106:90–96.

479. LeBlanc, D. J., and R. P. Mortlock. 1972. The metabolism of d-arabinose: alternate kinases for the phosphorylation of d-ribulose in Escherichia coli and Aerobacter aerogenes. Arch. Biochem. Biophys. 150:774–781.

480. Lederberg, E. 1955. Pleiotropy for maltose fermentation and phage resistance in Escherichia coli K-12. Genetics 40:580–581.

481. Lederberg, E. 1960. Genetic and functional aspects of galactose metabolism in Escherichia coli K-12. Symp. Soc. Gen. Microbiol. 10:115–136.

482. Lederberg, E. M., and J. Lederberg. 1953. Genetic studies of lysogenicity in Escherichia coli. Genetics 38:51–64.

483. Lederberg, J. 1950. The beta-d-galactosides of Escherichia coli, strain K-12. J. Bacteriol. 60:381–392.

484. Lee, C. A., G. R. Jacobson, and M. H. Saier, Jr. 1981. Plasmid-directed synthesis of enzymes required for d-mannitol transport and utilization in Escherichia coli. Proc. Natl. Acad. Sci. USA 78:7336–7340.

485. Lee, C. A., and M. H. Saier, Jr. 1983. Mannitol-specific enzyme II of the bacterial phosphotransferase system. III. The nucleotide sequence of the permease gene. J. Biol. Chem. 258:10761–10767.

486. Lee, C. A., and M. H. Saier, Jr. 1983. Use of cloned mtl genes of Escherichia coli to introduce mtl deletion mutations into the chromosome. J. Bacteriol. 153:685–692.

487. Lee, J.-H., S. Al-Zarban, and G. Wilcox. 1981. Genetic characterization of the araE gene in Salmonella typhimurium LT2. J. Bacteriol. 146:298–304.

488. Lee, J.-H., L. Heffernan, and G. Wilcox. 1980. Isolation of ara-lac gene fusions in Salmonella typhimurium LT-2 by using transducing bacteriophage Mu d(Ap^rlac). J. Bacteriol. 143:1325–1331.

489. Lee, J.-H., J. Nishitani, and G. Wilcox. 1984. Genetic characterization of Salmonella typhimurium LT2 ara mutations. J. Bacteriol. 158:344–346.

490. Lee, J.-H., R. J. Russo, L. Heffernan, and G. Wilcox. 1982. Regulation of l-arabinose transport in Salmonella typhimurium LT2. Mol. Gen. Genet. 185:136–141.

491. Lee, N., and I. Bendet. 1967. Crystalline l-ribulokinase from Escherichia coli. J. Biol. Chem. 242:2043–2050.

492. Lee, N., and E. Englesberg. 1962. Dual effects of structural genes in Escherichia coli. Proc. Natl. Acad. Sci. USA 48:335–348.

493. Lee, N. L., W. O. Gielow, and R. G. Wallace. 1981. Mechanism of araC autoregulation and the domains of two overlapping promoters, P_C and P_BAD, in the l-arabinose regulatory region of Escherichia coli. Proc. Natl. Acad. Sci. USA 78:752–756.

494. Leer, J. C., and K. Hammer-Jespersen. 1975. Multiple forms of phosphodeoxyribomutase from Escherichia coli. Physical and chemical characterization. Biochemistry 14:599–607.

495. Leer, J. C., K. Hammer-Jespersen, and M. Schwartz. 1977. Uridine phosphorylase from Escherichia coli. Physical and chemical characterization. Eur. J. Biochem. 75:217–224.

496. Leifer, Z., R. Engel, and B. E. Tropp. 1977. Transport of 3,4-dihydroxybutyl-1-phosphate, an analogue of sn-glycerol 3-phosphate. J. Bacteriol. 130:968–971.

497. Le Minor, L., C. Coynault, and G. Pessoa. 1974. Determinisme plasmidique du caractère atypique "lactose positif" de souches de Salmonella typhimurium et de Salmonella oranienbourg isolées du Bresil lors d’épidemies de 1971 à 1973. Ann. Microbiol. (Paris) 125A:261–285.

498. Le Minor, L., C. Coynault, R. Rohde, B. Rowe, and S. Aleksic. 1973. Localisation plasmidique du determinant génétique du caractère atypique "saccharose⁺" des Salmonella. Ann. Inst. Pasteur Microbiol. 124B:295–306.

499. Lengeler, J. 1975. Mutations affecting transport of the hexitols d-mannitol, d-glucitol, and galactitol in Escherichia coli K-12: isolation and mapping. J. Bacteriol. 124:26–38.

500. Lengeler, J. 1975. Nature and properties of hexitol transport systems in Escherichia coli. J. Bacteriol. 124:39–47.

501. Lengeler, J. 1977. Analysis of mutations affecting the dissimilation of galactitol (dulcitol) in Escherichia coli K12. Mol. Gen. Genet. 152:83–91.

502. Lengeler, J. 1980. Characterization of mutants of Escherichia coli K-12, selected by resistance to streptozotocin. Mol. Gen. Genet. 179:49–54.

503. Lengeler, J., A.-M. Auburger, R. Mayer, and A. Pecher. 1981. The phosphoenolpyruvate-dependent carbohydrate: phosphotransferase system enzymes II as chemoreceptors in chemotaxis of Escherichia coli K12. Mol. Gen. Genet. 183:163–170.

504. Lengeler, J., K. O. Hermann, H. J. Unsöld, and W. Boos. 1971. The regulation of the beta-methylgalactoside transport system and of the galactose binding protein of Escherichia coli K-12. Eur. J. Biochem. 19:457–470.

505. Lengeler, J., and E. C. C. Lin. 1972. Reversal of the mannitol-sorbitol diauxie in Escherichia coli. J. Bacteriol. 112:840–848.

506. Lengeler, J., R. J. Mayer, and K. Schmid. 1982. Phosphoenolpyruvate-dependent phosphotransferase system enzyme III and plasmid-encoded sucrose transport in Escherichia coli K-12. J. Bacteriol. 151:468–471.

507. Lengeler, J., and H. Steinberger. 1978. Analysis of regulatory mechanisms controlling the synthesis of the hexitol transport systems in Escherichia coli K-12. Mol. Gen. Genet. 164:163–169.

508. Lengeler, J., and H. Steinberger. 1978. Analysis of regulatory mechanisms controlling the activity of the hexitol transport systems in Escherichia coli K-12. Mol. Gen. Genet. 167:75–82.

509. Leonard, J., and M. H. Saier, Jr. 1981. Genetic dissection of catalytic activities of the Salmonella typhimurium mannitol enzyme II. J. Bacteriol. 145:1106–1109.

510. Leonard, J. E., and M. H. Saier, Jr. 1983. Mannitol-specific enzyme II of the bacterial phosphotransferase system. II. Reconstitution of vectorial transphosphorylation in phospholipid vesicles. J. Biol. Chem. 258:10757–10760.

511. Lerner, S. A., T. T. Wu, and E. C. C. Lin. 1964. Evolution of catabolic pathway in bacteria. Science 146:1313–1315.

512. Lester, G. 1952. The beta-galactosidase of lactose mutants of Escherichia coli K-12. Arch. Biochem. Biophys. 40:390–401.

513. Lester, G., and D. M. Bonner. 1952. The occurrence of beta-galactosidase in Escherichia coli. J. Bacteriol. 63:759–769.

514. Leung, K.-K., and D. W. Visser. 1977. Uridine and cytidine transport in Escherichia coli B and transport-deficient mutants. J. Biol. Chem. 252:2492–2497.

515. Levinthal, M. 1971. Biochemical studies of melibiose metabolism in wild-type and mel mutant strains of Salmonella typhimurium. J. Bacteriol. 105:1047–1052.

516. Lieb, M., J. J. Weigle, and E. Kellenberger. 1955. A study of hybrids between two strains of Escherichia coli. J. Bacteriol. 69:468–471.

517. Lin, E. C. C. 1970. The genetics of bacterial transport systems. Annu. Rev. Genet. 4:225–262.

517a. Lin, E. C. C. 1976. Glycerol dissimilation and its regulation in bacteria. Annu. Rev. Microbiol. 30:535–578.

518. Lin, E. C. C., J. P. Koch, T. M. Chused, and S. E. Jorgensen. 1962. Utilization of l-alpha-glycerophosphate by Escherichia coli without hydrolysis. Proc. Natl. Acad. Sci. USA 48:2145–2150.

519. Lin, E. C. C., and T. T. Wu. 1984. Functional divergence of the l-fucose system in mutants of Escherichia coli, p. 135–164. In R. P. Mortlock (ed.), Microorganisms as Model Systems for Studying Evolution. Plenum Publishing Corp., New York.

520. Lin, J. J.-C., and H. C. P. Wu. 1976. Biosynthesis and assembly of envelope lipoprotein in a glycerol-requiring mutant of Salmonella typhimurium. J. Bacteriol. 125:892–904.

521. Lin, R.-J., and C. W. Hill. 1983. Mapping the xyl, mtl, and lct loci in Escherichia coli K-12. J. Bacteriol. 156:914–916.

522. Link, C. D., and A. M. Reiner. 1982. Inverted repeats surround the ribitol-arabitol genes of E. coli C. Nature (London) 298:94–96.

523. Link, C. D., and A. M. Reiner. 1983. Genotypic exclusion: a novel relationship between ribitol-arabitol and galactitol genes of E. coli. Mol. Gen. Genet. 189:337–339.

524. Lo, T. C. Y. 1977. The molecular mechanism of dicarboxylic acid transport in Escherichia coli K12. J. Supramol. Struct. 7:463–480.

525. Lo, T. C. Y., and M. A. Bewick. 1978. The molecular mechanisms of dicarboxylic acid transport in Escherichia coli K12. J. Biol. Chem. 253:7826–7831.

526. Lo, T. C. Y., and M. A. Bewick. 1981. Use of a nonpenetrating substrate analogue to study the molecular mechanism of the outer membrane dicarboxylate transport system in Escherichia coli K12. J. Biol. Chem. 256:5511–5517.

527. Lo, T. C. Y., M. K. Rayman, and B. D. Sanwal. 1972. Transport of succinate in Escherichia coli. I. Biochemical and genetic studies of transport in whole cells. J. Biol. Chem. 247:6323–6331.

528. Lo, T. C. Y., M. K. Rayman, and B. D. Sanwal. 1974. Transport of succinate in Escherichia coli. III. Biochemical and genetic studies of the mechanism of transport in membrane vesicles. Can. J. Biochem. 52:854–866.

529. Lo, T. C. Y., and B. D. Sanwal. 1975. Isolation of the soluble substrate recognition component of the dicarboxylate transport system of Escherichia coli. J. Biol. Chem. 250:1600–1602.

530. Lo, T. C. Y., and B. D. Sanwal. 1975. Genetic analysis of mutants of Escherichia coli defective in dicarboxylate transport. Mol. Gen. Genet. 140:303–307.

531. Lo, T. C. Y., and B. D. Sanwal. 1975. Membrane bound substrate recognition compounds of the dicarboxylic transport system in Escherichia coli. Biochem. Biophys. Res. Commun. 63:278–285.

532. Lomax, M. S., and G. R. Greenberg. 1968. Characteristics of the deo operon: role in thymine utilization and sensitivity to deoxyribonucleotides. J. Bacteriol. 96:501–514.

533. Long, C. 1955. Studies involving enzyme phosphorylation. 4. Conversion of d-ribose into d-ribose 5-phosphate by extract of Escherichia coli. Biochem. J. 59:322–329.

534. Lopilato, J., T. Tsuchiya, and T. H. Wilson. 1978. Role of Na⁺ and Li⁺ in thiomethylgalactoside transport by the melibiose transport system of Escherichia coli. J. Bacteriol. 134:147–156.

535. Lopilato, J. E., J. L. Garwin, S. D. Emr, T. J. Silhavy, and J. R. Beckwith. 1984. d-Ribose metabolism in Escherichia coli K-12: genetics, regulation, and transport. J. Bacteriol. 158:665–673.

536. Lowe, D. A., and J. M. Turner. 1970. Microbial metabolism of amino ketones: d-1-aminopropan-2-ol and aminoacetone metabolism in Escherichia coli. J. Gen. Microbiol. 63:49–61.

537. Luckey, M., and H. Nikaido. 1980. Specificity of diffusion channels produced by lambda phage receptor protein of Escherichia coli. Proc. Natl. Acad. Sci. USA 77:167–171.

538. Ludtke, D., T. J. Larson, C. Beck, and W. Boos. 1982. Only one gene is required for the glpT-dependent transport of sn-glycerol-3-phosphate in Escherichia coli. Mol. Gen. Genet. 186:540–547.

539. Macpherson, A. J. S., M. C. Jones-Mortimer, and P. J. F. Henderson. 1981. Identification of the araE transport protein of Escherichia coli. Biochem. J. 196:269–283.

540. Macpherson, A. J. S., M. C. Jones-Mortimer, P. Horne, and P. J. F. Henderson. 1983. Identification of the GalP galactose transport protein of Escherichia coli. J. Biol. Chem. 258:4390–4396.

541. Mahoney, W. C., R. W. Hogg, and M. A. Hermodson. 1981. The amino acid sequence of the d-galactose-binding protein from Escherichia coli B/r. J. Biol. Chem. 256:4350–4356.

542. Majumdar, A., and S. Adhya. 1984. Demonstration of two operator elements in gal: in vitro repressor binding studies. Proc. Natl. Acad. Sci. USA 81:6100–6104.

543. Maleszka, R., P. Y. Wang, and H. Schneider. 1982. A colE1 hybrid plasmid containing Escherichia coli genes complementing d-xylose negative mutants of Escherichia coli and Salmonella typhimurium. Can. J. Biochem. 60:144–151.

544. Maloney, P. C., E. R. Kashket, and T. H. Wilson. 1975. Methods for studying transport in bacteria, p. 1–49. In E. D. Korn (ed.), Methods in Membrane Biology, vol. 5. Plenum Publishing Corp., New York.

545. Mandrand-Berthelot, M.-A., and A. E. Lagarde. 1982. Altered transport properties in Escherichia coli mutants selected for pH-conditional growth on 3-deoxy-2-oxo-d-gluconate. J. Biol. Chem. 257:8806–8816.

546. Mandrand-Berthelot, M.-A., P. Ritzenthaler, and M. Mata-Gilsinger. 1984. Construction and expression of hybrid plasmids containing the structural gene of the Escherichia coli K-12 3-deoxy-2-oxo-d-gluconate transport system. J. Bacteriol. 160:600–606.

547. Manning, P. A., and P. Reeves. 1978. Outer membrane proteins of Escherichia coli K-12: isolation of a common receptor protein for bacteriophage T6 and colicin K. Mol. Gen. Genet. 158:279–286.

548. Mans, R. J., and A. L. Koch. 1960. Metabolism of adenosine and deoxyadenosine by growing cultures of Escherichia coli. J. Biol. Chem. 235:450–456.

549. Manson, L. A., and J. O. Lampon. 1951. The metabolism of desoxyribose nucleosides in Escherichia coli. J. Biol. Chem. 193:539–547.

550. Mao, B., and J. A. McCammon. 1983. Theoretical study of hinge bending in l-arabinose-binding protein. Internal energy and free energy changes. J. Biol. Chem. 258:12543–12547.

551. Mao, B., and J. A. McCammon. 1984. Structural study of hinge bending in l-arabinose-binding protein. J. Biol. Chem. 259:4964–4970.

552. Mao, B., M. R. Pear, J. A. McCammon, and F. A. Quiocho. 1982. Hinge-bending in l-arabinose-binding protein. J. Biol. Chem. 257:1131–1133.

553. Marechal, L. R. 1984. Transport and metabolism of trehalose in Escherichia coli and Salmonella typhimurium. Arch. Microbiol. 137:70–73.

554. Markovitz, A., R. J. Sydiskis, and M. M. Lieberman. 1967. Genetic and biochemical studies on mannose-negative mutants that are deficient in phosphomannose isomerase in Escherichia coli K-12. J. Bacteriol. 94:1492–1496.

555. Markovitz, A. M., M. Lieberman, and N. Rosenbaum. 1967. Derepression of phosphomannose isomerase by regulator gene mutations involved in capsular polysaccharide synthesis in Escherichia coli K-12. J. Bacteriol. 94:1497–1501.

556. Mata, M., M. Delstanche, and J. Robert-Baudouy. 1978. Isolation of specialized transducing bacteriophages carrying the structural genes of the hexuronate system in Escherichia coli K-12: exu region. J. Bacteriol. 133:549–557.

557. Mata-Gilsinger, M., and P. Ritzenthaler. 1983. Physical mapping of the exuT and uxaC operators by use of exu plasmids and generation of deletion mutants in vitro. J. Bacteriol. 155:973–982.

558. Mata-Gilsinger, M., P. Ritzenthaler, and J. Robert-Baudouy. 1978. Identification de plasmides transportant la region uxu du système des hexuronates chez Escherichia coli K-12 à partir de la collection de Clarke et Carbon. C.R. Acad. Sci. Ser. D 286:237–239.

559. Matin, A., and W. N. Konings. 1973. Transport of lactate and succinate by membrane vesicles of Escherichia coli, Bacillus subtilis and a Pseudomonas species. Eur. J. Biochem. 34:58–67.

560. McEntee, K. 1977. Genetic analysis of the Escherichia coli K-12 srl region. J. Bacteriol. 132:904–911.

561. McGowan, E. B., T. J. Silhavy, and W. Boos. 1974. Involvement of a tryptophan residue in the binding site of Escherichia coli galactose-binding protein. Biochemistry 13:993–999.

562. McKeown, M., M. Kahn, and P. Hanawalt. 1976. Thymidine uptake and utilization in Escherichia coli: a new gene controlling nucleoside transport. J. Bacteriol. 126:814–822.

563. Miki, K., and E. C. C. Lin. 1973. Enzyme complex which couples glycerol-3-phosphate dehydrogenation to fumarate reduction in Escherichia coli. J. Bacteriol. 114:767–771.

564. Miki, K., and E. C. C. Lin. 1975. Anaerobic energy-yielding reaction associated with transhydrogenation from glycerol 3-phosphate to fumarate by an Escherichia coli system. J. Bacteriol. 124:1282–1287.

565. Miki, K., and E. C. C. Lin. 1975. Electron transport chain from glycerol 3-phosphate to nitrate in Escherichia coli. J. Bacteriol. 124:1288–1294.

566. Miki, K., and E. C. C. Lin. 1980. Use of Escherichia coli operon-fusion strains for the study of glycerol 3-phosphate transport activity. J. Bacteriol. 143:1436–1443.

567. Miki, K., T. J. Silhavy, and K. J. Andrews. 1979. Resolution of glpA and glpT loci into separate operons in Escherichia coli K-12 strains. J. Bacteriol. 138:268–269.

568. Miki, K., and T. H. Wilson. 1978. Proton translocation associated with anaerobic transhydrogenation from glycerol 3-phosphate to fumarate in Escherichia coli. Biochem. Biophys. Res. Commun. 83:1570–1575.

569. Miki, T., S. Hiraga, T. Nagata, and T. Yura. 1978. Bacteriophage lambda carrying the Escherichia coli chromosomal region of the replication origin. Proc. Natl. Acad. Sci. USA 75:5099–5103.

570. Miller, D. M., III, J. S. Olson, and F. A. Quiocho. 1980. The mechanism of sugar binding to the periplasmic receptor for galactose chemotaxis and transport in Escherichia coli. J. Biol. Chem. 255:2465–2471.

571. Monod, J. 1947. The phenomenon of enzymatic adaptation. Growth 11:223–289.

572. Monod, J., and A. Audureau. 1946. Mutation et adaptation enzymatique chez Escherichia coli-mutabile. Ann. Inst. Pasteur (Paris) 72:868–878.

573. Monod, J., G. Cohen-Bazire, and M. Cohn. 1951. Sur la biosynthèse de la beta-galactosidase (lactase) chez Escherichia coli. La specificité de l’induction. Biochim. Biophys. Acta 7:585–599.

574. Monod, J., and A.-M. Torriani. 1948. Synthèse d’un polysaccharide du type amidon aux depons du maltose, en presence d’un extrait enzymatique d’origine bactérienne. C.R. Acad. Sci. Ser. D 227:240–242.

575. Monod, J., and A. M. Torriani. 1950. De l’amylomaltase d’Escherichia coli. Ann. Inst. Pasteur (Paris) 78:65–77.

576. Morgenroth, A., and J. P. Duguid. 1968. Demonstration of different mutational sites controlling rhamnose fermentation in FIRN and non-FIRN rha-strains of Salmonella typhimurium: an essay in bacterial archaeology. Genet. Res. 11:151–169.

577. Morse, M. L. 1962. Preliminary genetic map of seventeen galactose mutations in Escherichia coli K-12. Proc. Natl. Acad. Sci. USA 48:1314–1318.

578. Morse, M. L., E. M. Lederberg, and J. Lederberg. 1956. Transduction in Escherichia coli K-12. Genetics 41:142–156.

579. Morse, M. L., E. M. Lederberg, and J. Lederberg. 1956. Transductional heterogenotes in Escherichia coli. Genetics 41:758–779.

580. Mortlock, R. P., D. D. Fossitt, and W. A. Wood. 1965. A basis for utilization of unnatural pentoses and pentitols by Aerobacter aerogenes. Proc. Natl. Acad. Sci. USA 54:572–579.

581. Mortlock, R. P., and D. C. Old. 1979. Utilization of d-xylose by wild-type strains of Salmonella typhimurium. J. Bacteriol. 137:173–178.

582. Mowbray, S. L., and G. A. Petsko. 1982. Preliminary X-ray data for the ribose binding protein from Salmonella typhimurium. J. Mol. Biol. 160:545–547.

583. Mowbray, S. L., and G. A. Petsko. 1983. The X-ray structure of the periplasmic galactose binding protein from Salmonella typhimurium at 3.0-Å resolution. J. Biol. Chem. 258:7991–7997.

584. Müller, N., H.-G. Heine, and W. Boos. 1982. Cloning of mglB: the structural gene for the galactose-binding protein of Salmonella typhimurium and Escherichia coli. Mol. Gen. Genet. 185:473–480.

585. Müller, N., H.-G. Heine, and W. Boos. 1985. Characterization of the Salmonella typhimurium mgl operon and its gene products. J. Bacteriol. 163:37–45.

586. Müller-Hill, B., H. V. Rickenborg, and K. Wallenfels. 1964. Specificity of the induction of the enzymes of the lac operon in Escherichia coli. J. Mol. Biol. 10:303–318.

587. Munch-Petersen, A. 1968. On the catabolism of deoxyribonucleosides in cells and cell extracts of Escherichia coli. Eur. J. Biochem. 6:432–442.

588. Munch-Petersen, A. 1968. Thymineless mutants of E. coli with deficiencies in deoxyribomutase and deoxyriboaldolase. Biochim. Biophys. Acta 161:279–282.

589. Munch-Petersen, A. 1970. Deoxyribonucleoside catabolism and thymine incorporation in mutants of Escherichia coli lacking deoxyriboaldolase. Eur. J. Biochem. 15:191–202.

590. Munch-Petersen, A., and B. Mygind. 1976. Nucleoside transport systems in Escherichia coli K-12: specificity and regulation. J. Cell. Physiol. 89:551–559.

591. Munch-Petersen, A., and B. Mygind. 1983. Transport of nucleic acid precursors, p. 259–309. In A. Munch-Petersen (ed.), Metabolism of Nucleotides, Nucleosides and Nucleobases in Microorganisms. Academic Press, Inc. (London), Ltd., London.

592. Munch-Petersen, A., B. Mygind, A. Nicolaisen, and N. J. Pihl. 1979. Nucleoside transport in cells and membrane vesicles from Escherichia coli K12. J. Biol. Chem. 254:3730–3737.

593. Munch-Petersen, A., P. Nygaard, K. Hammer-Jespersen, and N. Fiil. 1972. Mutants constitutive for nucleoside catabolizing enzymes in Escherichia coli K 12. Isolation, characterization and mapping. Eur. J. Biochem. 27:208–215.

594. Munch-Petersen, A., and N. J. Pihl. 1980. Stimulatory effect of low ATP pools on transport of purine nucleosides in cells of Escherichia coli. Proc. Natl. Acad. Sci. USA 77:2519–2523.

595. Murakawa, S., K. Izaki, and H. R. Takahashi. 1971. Succinate transport in isolated membrane preparations from Escherichia coli. Agric. Biol. Chem. 35:1992–1993.

596. Musso, R., R. Di Lauro, M. Rosenberg, and B. de Crombrugghe. 1977. Nucleotide sequence of the operator-promoter region of the galactose operon of Escherichia coli. Proc. Natl. Acad. Sci. USA 74:106–110.

597. Musso, R. E., R. DiLauro, S. Adhya, and B. de Crombrugghe. 1977. Dual control for transcription of the galactose operon by cyclic AMP and its receptor protein at two interspersed promoters. Cell 12:847–854.

598. Musso, R. E., and I. Zabin. 1973. Substrate specificity and kinetic studies on thiogalactoside transacetylase. Biochemistry 12:553–557.

599. Mygind, B., and A. Munch-Petersen. 1975. Transport of pyrimidine nucleosides in cells of Escherichia coli K 12. Eur. J. Biochem. 59:365–372.

600. Nagelkerke, F., and P. W. Postma. 1978. 2-Deoxygalactose, a specific substrate of the Salmonella typhimurium galactose permease: its use for the isolation of galP mutants. J. Bacteriol. 133:607–613.

601. Nakae, T. 1971. Multiple molecular forms of uridine diphosphate glucose pyrophosphorylase from Salmonella typhimurium. III. Interconversion between various forms. J. Biol. Chem. 246:4404–4411.

602. Nakae, T., and H. Nikaido. 1971. Multiple molecular forms of uridine diphosphate glucose pyrophosphorylase from Salmonella typhimurium. I. Catalytic properties of various forms. J. Biol. Chem. 246:4386–4396.

603. Nakae, T., and H. Nikaido. 1971. Multiple molecular forms of uridine diphosphate glucose pyrophosphorylase from Salmonella typhimurium. II. Genetic determination of multiple forms. J. Biol. Chem. 246:4397–4403.

604. Nelson, S. O., and P. W. Postma. 1984. Interactions in vivo between III^Glc of the phosphoenolpyruvate:sugar phosphotransferase system and the glycerol and maltose uptake systems of Salmonella typhimurium. Eur. J. Biochem. 139:29–34.

605. Nemoz, G., J. Robert-Baudouy, and F. R. Stoeber. 1976. Physiological and genetic regulation of the aldohexuronate transport system in Escherichia coli. J. Bacteriol. 127:706–718.

606. Neuhard, J., and J. L. Ingraham. 1968. Mutants of Salmonella typhimurium requiring cytidine for growth. J. Bacteriol. 95:2431–2433.

607. Newcomer, M. E., G. L. Gilliland, and F. A. Quiocho. 1981. l-Arabinose-binding protein-sugar complex at 2.4 Å resolution. J. Biol. Chem. 256:13213–13217.

608. Newcomer, M. E., D. M. Miller III, and F. A. Quiocho. 1979. Location of the sugar-binding site of l-arabinose-binding protein. Sugar derivative syntheses, sugar binding specificity, and different Fourier analyses. J. Biol. Chem. 254:7529–7533.

609. Niiya, S., K. Yamasaki, T. H. Wilson, and T. Tsuchiya. 1982. Altered cation coupling to melibiose transport in mutants of Escherichia coli. J. Biol. Chem. 257:8902–8906.

610. Nikaido, H. 1961. Galactose-sensitive mutants of Salmonella. I. Metabolism of galactose. Biochim. Biophys. Acta 48:460–469.

611. Nikaido, H., and T. Fukasawa. 1961. The effect of mutation in a structural gene on the inducibility of the enzymes controlled by other genes of the same operon. Biochem. Biophys. Res. Commun. 4:338–342.

612. Novel, G., M. L. Didier-Fichet, and F. Stoeber. 1974. Inducibility of beta-glucuronidase in wild-type and hexuronate-negative mutants of Escherichia coli K-12. J. Bacteriol. 120:89–95.

613. Novel, G., and M. Novel. 1973. Mutants d’Escherichia coli K-12 affectés pour leur croissance sur methyl-beta-d-glucuronide: localisation du gene de structure de la beta-d-glucuronidase (uidA). Mol. Gen. Genet. 120:319–335.

614. Novel, G., M. Novel, M.-L. Didier-Fichet, and F. Stoeber. 1970. Etude génétique de mutants du système de degradation des hexuronides chez Escherichia coli K 12. C.R. Acad. Sci. Ser. D 271:457–460.

615. Novel, G., and F. Stoeber. 1973. Individualité de la d-glucuronate-cetol isomerase d’Escherichia coli K12. Biochimie 55:1057–1070.

616. Novel, M., and G. Novel. 1971. Mutations gur: localisation precise du locus gurA gene de structure de la beta-glucuronidase chez Escherichia coli K12. C.R. Acad. Sci. Ser. D 273:2691–2693.

617. Novel, M., and G. Novel. 1974. Mutants d’Escherichia coli K12 capables de croitre sur methyl-beta-d-galacturonide: mutants simples constitutifs pour la synthèse de la beta-glucuronidase et mutants doubles dereprimés aussi pour la synthèse de deux enzymes d’utilisation du glucuronate. C.R. Acad. Sci. Ser. D 279:695–698.

618. Novel, M., and G. Novel. 1976. Regulation of beta-glucuronidase synthesis in Escherichia coli K-12: constitutive mutants specifically derepressed for uidA expression. J. Bacteriol. 127:406–417.

619. Novel, M., and G. Novel. 1976. Regulation of beta-glucuronidase synthesis in Escherichia coli K-12: pleiotropic constitutive mutations affecting uxu and uidA expression. J. Bacteriol. 127:418–432.

620. Novotny, C. P., and E. Englesberg. 1966. The l-arabinose permease system in Escherichia coli B/r. Biochim. Biophys. Acta 117:217–230.

621. Novotny, M. J., W. L. Frederickson, E. B. Waygood, and M. H. Saier, Jr. 1985. Allosteric deregulation of glycerol kinase by enzyme III Glc of the phosphotransferase system in Escherichia coli and Salmonella typhimurium. J. Bacteriol. 162:810–816.

622. Novotny, M. J., J. Reizer, F. Esch, and M. H. Saier, Jr. 1984. Purification and properties of d-mannitol-1-phosphate dehydrogenase and d-glucitol-6-phosphate dehydrogenase from Escherichia coli. J. Bacteriol. 159:986–990.

623. Nygaard, P. 1973. Nucleoside-catabolizing enzymes in Salmonella typhimurium. Induction by ribonucleosides. Eur. J. Biochem. 36:267–272.

624. Nygaard, P. 1978. Adenosine deaminase from Escherichia coli. Methods Enzymol. 51:508–512.

625. Ogden, S., D. Haggerty, C. M. Stoner, D. Koldrubetz, and R. Schleif. 1980. The Escherichia coli l-arabinose operon: binding sites of the regulatory proteins and a mechanism of positive and negative regulation. Proc. Natl. Acad. Sci. USA 77:3346–3350.

626. Okada, T. 1966. Mutational site of the gene controlling quantitative thymine requirement in Escherichia coli K 12. Genetics 54:1329–1336.

627. Old, D. C. 1972. Temperature-dependent utilization of mesoinositol: a useful biotyping marker in the genealogy of Salmonella typhimurium. J. Bacteriol. 112:779–783.

628. Old, D. C., P. F. H. Dawes, and R. M. Barker. 1980. Transduction of inositol-fermenting ability demonstrating phylogenic relationships among strains of Salmonella typhimurium. Genet. Res. 35:215–224.

629. Old, D. C., and R. P. Mortlock. 1977. The metabolism of d-arabinose by Salmonella typhimurium. J. Gen. Microbiol. 101:341–344.

630. Old, D. C., and R. P. Mortlock. 1979. Phylogenetic relationships between different d-xylose biogroups in wild-type Salmonella typhimurium strains and a suggested evolutionary pathway. J. Appl. Bacteriol. 47:167–174.

631. Oosawa, K., and Y. Imae. 1983. Glycerol and ethylene glycol: members of a new class of repellents of Escherichia coli chemotaxis. J. Bacteriol. 154:104–112.

632. Oosawa, K., and Y. Imae. 1984. Demethylation of methyl-accepting chemotaxis proteins in Escherichia coli induced by the repellents glycerol and ethylene glycol. J. Bacteriol. 157:576–581.

633. Ordal, G. W., and J. Adler. 1974. Isolation and complementation of mutants in galactose taxis and transport. J. Bacteriol. 117:509–516.

634. Ordal, G. W., and J. Adler. 1974. Properties of mutants in galactose taxis and transport. J. Bacteriol. 117:517–526.

635. Ornston, L. N., and M. K. Ornston. 1969. Regulation of glyoxylate metabolism in Escherichia coli K-12. J. Bacteriol. 98:1098–1108.

636. Orr, G. A., J. W. Hammelburger, and G. Heney. 1983. Interaction of sn-glycerol 3-phosphorothioate with Escherichia coli. In vitro and in vivo incorporation into phospholipids. J. Biol. Chem. 258:9237–9244.

637. Orskov, I., and F. Orskov. 1973. Plasmid-determined H₂S character in Escherichia coli and its relation to plasmid-carried raffinose fermentation and tetracycline resistance characters. Examination of 32 H₂S-positive strains isolated during the years 1950 to 1971. J. Gen. Microbiol. 77:487–499.

638. Osborn, M. J., S. M. Rosen, L. Rothfield, and B. L. Horecker. 1962. Biosynthesis of bacterial lipopolysaccharide. I. Enzymatic incorporation of galactose in a mutant strain of Salmonella. Proc. Natl. Acad. Sci. USA 48:1831–1838.

639. Ott, J. L., and C. H. Werkman. 1957. Coupled nucleoside phosphorylase reactions in Escherichia coli. Arch. Biochem. Biophys. 69:264–276.

640. Overath, P., and J. K. Wright. 1983. Lactose permease: a carrier on the move. Trends Biochem. Sci. 8:404–408.

641. Paege, L. M., and F. Schlenk. 1950. Pyrimidine riboside metabolism. Arch. Biochim. Biophys. 28:348–358.

642. Page, M. G. P., and K. Burton. 1978. The location of purine phosphoribosyl-transferase activities in Escherichia coli. Biochem. J. 174:717–725.

643. Pahel, G., F. R. Bloom, and B. Tyler. 1979. Deletion mapping of the polA-metB region of the Escherichia coli chromosome. J. Bacteriol. 138:653–656.

644. Palchaudhuri, S., S. Rahn, D. S. Santos, and W. K. Maas. 1977. Characterization of plasmids in a sucrose-fermenting strain of Escherichia coli. J. Bacteriol. 130:1402–1403.

645. Palmer, T. N., B. E. Ryman, and W. J. Whelan. 1968. The action pattern of amylomaltase. FEBS Lett. 1:1–3.

646. Palmer, T. N., G. Wöber, and W. J. Whelan. 1973. The pathway of exogenous and endogenous carbohydrate utilization in Escherichia coli: a dual function for the enzymes of the maltose operon. Eur. J. Biochem. 39:601–612.

647. Palva, E. T. 1978. Major outer membrane protein in Salmonella typhimurium induced by maltose. J. Bacteriol. 136:286–294.

648. Palva, E. T. 1979. Relationship between ompB genes of Escherichia coli and Salmonella typhimurium. FEMS Microbiol. Lett. 5:205–209.

649. Palva, E. T., P. Liljeström, and S. Harayama. 1981. Cosmid cloning and transposon mutagenesis in Salmonella typhimurium using phage lambda vehicles. Mol. Gen. Genet. 181:153–157.

649a. Palva, E. T., P. Saris, and T. J. Silhavy. 1985. Gene fusions to the pstM/pel locus of Escherichia coli. Mol. Gen. Genet. 199:427–433.

650. Palva, E. T., and P. Westermann. 1979. Arrangement of the maltose-inducible major outer membrane proteins, the bacteriophage lambda receptor in Escherichia coli and the 44K protein in Salmonella typhimurium. FEBS Lett. 99:77–80.

651. Pardee, A. B. 1957. An inducible mechanism for accumulation of melibiose in Escherichia coli. J. Bacteriol. 73:376–385.

652. Parks, R. E., Jr., and R. P. Agarwal. 1972. Purine nucleoside phosphorylase, p. 483–514. In P. D. Boyer (ed.), The Enzymes, vol. 7. Academic Press, Inc., New York.

653. Parnes, J. R., and W. Boos. 1973. Energy coupling of the beta-methylgalactoside transport system of Escherichia coli. J. Biol. Chem. 248:4429–4435.

654. Parsons, R. G., and R. W. Hogg. 1974. Crystallization and characterization of the l-arabinose-binding protein of Escherichia coli B/r. J. Biol. Chem. 249:3602–3607.

655. Parsons, R. G., and R. W. Hogg. 1974. A comparison of the l-arabinose and d-galactose-binding proteins of Escherichia coli B/r. J. Biol. Chem. 249:3608–3614.

656. Peterkofsky, A., and C. Gazdar. 1979. Escherichia coli adenylate cyclase complex: regulation by the proton electrochemical gradient. Proc. Natl. Acad. Sci. USA 76:1099–1103.

657. Peterson, R. M., J. Boniface, and A. L. Koch. 1967. Energy requirements, interactions and distinctions in the mechanisms for transport of various nucleosides in Escherichia coli. Biochim. Biophys. Acta 135:771–783.

658. Peterson, R. N., and A. L. Koch. 1966. The relationship of adenosine and inosine transport in Escherichia coli. Biochim. Biophys. Acta 126:129–145.

659. Pogell, B. M., B. R. Maity, S. Frumkin, and S. Shapiro. 1966. Induction of an active transport system for glucose 6-phosphate in Escherichia coli. Arch Biochem. Biophys. 116:406–415.

660. Portalier, R., J. Robert-Baudouy, and F. Stoeber. 1980. Regulation of Escherichia coli K-12 hexuronate system genes: exu regulon. J. Bacteriol. 143:1095–1107.

661. Portalier, R., and F. Stoeber. 1972. Dosages colorimetriques des oxydoreductases aldoniques d’Escherichia coli K12: applications. Biochim. Biophys. Acta 289:19–27.

662. Portalier, R. C., J. M. Robert-Baudouy, and G. M. Nemoz. 1974. Studies of mutations in the uronic isomerase and altronic oxidoreductase structural genes of Escherichia coli K-12. Mol. Gen. Genet. 128:301–319.

663. Portalier, R. C., J. M. Robert-Baudouy, and F. R. Stoeber. 1972. Localisation génétique et caracterisation biochimique de mutations affectant le gene de structure de l’hydrolyase altronique chez Escherichia coli K12. Mol. Gen. Genet. 118:335–350.

664. Portalier, R. C., and F. R. Stoeber. 1972. La d-altronate: NAD-oxydoreductase d’Escherichia coli K-12: purification, propriétés et individualité. Eur. J. Biochem. 26:50–61.

665. Portalier, R. C., and F. R. Stoeber. 1972. La d-mannonate:NAD-oxydoreductase d’Escherichia coli K12: purification, propriétés et individualité. Eur. J. Biochem. 26:290–300.

666. Postma, P. W., W. Epstein, A. R. Schuitema, and S. O. Nelson. 1984. Interaction between III^Glc of the phosphoenolpyruvate: sugar phosphotransferase system and glycerol kinase of Salmonella typhimurium. J. Bacteriol. 158:351–353.

667. Postma, P. W., and J. W. Lengeler. 1985. Phosphoenolpyruvate: carbohydrate phosphotransferase system of bacteria. Microbiol. Rev. 49:232–269.

668. Pouyssegur, J. 1971. Localisation génétique de mutations 2-ceto-3-desoxy-6-phosphogluconate aldolase chez E. coli K12. Mol. Gen. Genet. 113:31–42.

669. Pouyssegur, J. 1972. Mutations affectant le gene de structure de la 2-ceto-3-desoxy-6-phosphogluconate aldolase chez Escherichia coli K12. Mol. Gen. Genet. 114:305–311.

670. Pouyssegur, J., and F. Stoeber. 1970. Production de 2-ceto-3-deoxy-6-phosphogluconate par un mutant d’Escherichia coli K12. Bull. Soc. Chim. Biol. 52:1407–1419.

671. Pouyssegur, J., and F. Stoeber. 1970. Sur la biosynthèse induite des deux dernières enzymes de la sequence degradative des hexuronates chez Escherichia coli K 12. C.R. Acad. Sci. Ser. D 271:370–373.

672. Pouyssegur, J., and F. Stoeber. 1970. Synthèse enzymatique du 2-ceto-3-desoxy-d-gluconate. Bull. Soc. Chim. Biol. 52:1419–1428.

673. Pouyssegur, J., and F. Stoeber. 1971. Etude du rameau degradatif commun des hexuronates chez Escherichia coli K12. Purification, propriétés et individualité de la 2-ceto-3-desoxy-d-gluconokinase. Biochimie 53:771–781.

674. Pouyssegur, J., and F. Stoeber. 1972. Controle physiologique et génétique du metabolisme du 2-ceto-3-desoxy-gluconate chez E. coli K12. C.R. Acad. Sci. Ser. D 274:2249–2252.

675. Pouyssegur, J. M., and A. Lagarde. 1973. Système de transport du 2-ceto-3-desoxy-gluconate chez E. coli K12: localization d’un gene de structure et de son operateur. Mol. Gen. Genet. 121:163–180.

676. Pouyssegur, J. M., and F. Stoeber. 1974. Genetic control of the 2-keto-3-deoxy-d-gluconate metabolism in Escherichia coli K-12: kdg regulon. J. Bacteriol. 117:641–651.

677. Pouyssegur, J. M., and F. R. Stoeber. 1971. Etude du rameau degradatif commun des hexuronates chez Escherichia coli K12. Purification, propriétés et individualité de la 2-ceto-3-desoxy-6-phospho-d-gluconate aldolase. Eur. J. Biochem. 21:363–373.

678. Pouyssegur, J. M., and F. R. Stoeber. 1972. Rameau degradatif commun des hexuronates chez Escherichia coli K12. Mécanisme d’induction des enzymes assurant le metabolisme du 2-ceto-3-desoxy-gluconate chez Escherichia coli K12. Eur. J. Biochem. 30:479–494.

679. Power, J. 1967. The l-rhamnose genetic system in Escherichia coli K-12. Genetics 55:557–568.

680. Prasad, I., and S. Schaefler. 1974. Regulation of the beta-glucoside system in Escherichia coli K-12. J. Bacteriol. 120:638–650.

681. Prasad, I., B. Young, and S. Schaefler. 1973. Genetic determination of the constitutive biosynthesis of phospho-alpha-glucosidase A in Escherichia coli K-12. J. Bacteriol. 114:909–915.

682. Prestidge, L. S., and A. B. Pardee. 1965. A second permease for methyl-thio-beta-d-galactoside in Escherichia coli. Biochim. Biophys. Acta 100:591–593.

683. Pritchard, R. H., and S. I. Ahmad. 1971. Fluoracil and the isolation of mutants lacking uridine phosphorylase in Escherichia coli: location of the gene. Mol. Gen. Genet. 111:84–88.

684. Pueyo, C. 1978. Forward mutations to arabinose resistance in Salmonella typhimurium strains. A sensitive assay for mutagenicity testing. Mutat. Res. 54:311–321.

685. Pueyo, C., and J. Lopez-Barea. 1979. The l-arabinose resistance test with Salmonella typhimurium strain SV-3 selects forward mutations at several 6ara genes. Mutat. Res. 64:249–258.

686. Quiocho, F. A., G. L. Gilliland, and G. N. Phillips, Jr. 1977. The 2.8 Å resolution structure of the l-arabinose-binding protein from Escherichia coli. Polypeptide chain folding, domain similarity, and probable location of sugar-binding site. J. Biol. Chem. 252:5142–5149.

687. Quiocho, F. A., W. E. Meador, and J. W. Pflugrath. 1979. Preliminary crystallographic data of receptors for transport and chemotaxis in Escherichia coli: d-galactose and maltose binding proteins. J. Mol. Biol. 133:181–184.

688. Quiocho, F. A., and N. K. Vyas. 1984. Novel stereospecificity of the l-arabinose-binding protein. Nature (London) 310:381–386.

689. Rachmeler, M., J. Gerhart, and J. Rosner. 1961. Limited thymidine uptake in Escherichia coli due to an inducible thymidine phosphorylase. Biochem. Biophys. Acta 49:222–225.

690. Racker, E. 1951. Enzymatic synthesis of deoxypentose phosphate. Nature (London) 167:408–409.

691. Racker, E. 1952. Enzymatic synthesis and breakdown of desoxyribose phosphate. J. Biol. Chem. 196:347–365.

692. Rader, R. L., and J. Hochstadt. 1976. Regulation of purine utilization in bacteria. VII. Involvement of membrane-associated nucleoside phosphorylases in the uptake and the base-mediated loss of the ribose moiety of nucleosides by Salmonella typhimurium membrane vesicles. J. Bacteriol. 128:290–301.

693. Ramos, S., and H. R. Kaback. 1977. pH-dependent changes in proton-substrate stoichiometries during active transport in Escherichia coli membrane vesicles. Biochemistry 16:4271–4275.

694. Randall-Hazelbauer, L. L., and M. Schwartz. 1973. Isolation of the bacteriophage lambda receptor from Escherichia coli K-12. J. Bacteriol. 116:1436–1446.

695. Ravdonikas, L. E. 1976. Production and characteristics of Salmonella typhimurium glycerin mutants. Zh. Mikrobiol. Epidemiol. Immunobiol. 12:29–32.

696. Rayman, M. K., T. C. Y. Lo, and B. D. Sanwal. 1972. Transport of succinate in Escherichia coli. II. Characteristics of uptake and energy coupling with transport in membrane preparations. J. Biol. Chem. 247:6332–6339.

697. Razzell, W. E., and P. Casshyap. 1964. Substrate specificity and induction of thymidine phosphorylase in Escherichia coli. J. Biol. Chem. 239:1789–1793.

698. Razzell, W. E., and G. G. Khorana. 1958. Purification and properties of a pyrimidine deoxyriboside phosphorylase from Escherichia coli. Biochim. Biophys. Acta 28:562–566.

699. Reiner, A. M. 1975. Genes for ribitol and d-arabitol catabolism in Escherichia coli: their loci in C strains and absence in K-12 and B strains. J. Bacteriol. 123:530–536.

700. Reithel, F. J., and J. C. Kim. 1960. Studies on the beta-galactosidase from Escherichia coli ML 308.1. The effect of some ions on enzymic activity. Arch. Biochem. Biophys. 90:271–277.

701. Remy, C. N., and S. H. Love. 1968. Induction of adenosine deaminase in Escherichia coli. J. Bacteriol. 96:76–85.

702. Rephaeli, A. W., and M. H. Saier, Jr. 1980. Substrate specificity and kinetic characterization of sugar uptake and phosphorylation catalyzed by the mannose enzyme II of the phosphotransferase system in Salmonella typhimurium. J. Biol. Chem. 255:8585–8591.

703. Reynolds, A. E., J. Felton, and A. Wright. 1981. Insertion of DNA activates the cryptic bgl operon in E. coli K12. Nature (London) 293:625–629.

704. Richarme, G. 1982. Associative properties of the Escherichia coli galactose binding protein and maltose binding protein. Biochem. Biophys. Res. Commun. 105:476–481.

705. Richarme, G. 1985. Possible involvement of lipoic acid in the binding protein-dependent transport systems in Escherichia coli. J. Bacteriol. 162:286–293.

706. Richey, D. P., and E. C. C. Lin. 1972. Importance of facilitated diffusion for effective utilization of glycerol by Escherichia coli. J. Bacteriol. 112:784–790.

707. Rickenberg, H. V., G. N. Cohen, and G. Buttin, and J. Monod. 1956. La galactoside-permease d’Escherichia coli. Ann. Inst. Pasteur (Paris) 91:829–857.

708. Riddle, D. L., and J. R. Roth. 1972. Frameshift suppressors. II. Genetic mapping and dominance studies. J. Mol. Biol. 66:483–493.

709. Riordan, C., and H. L. Kornberg. 1977. Location of galP, a gene which specifies galactose permease activity, on the Escherichia coli linkage map. Proc. R. Soc. Lond. B Biol. Sci. 198:401–410.

710. Ritzenthaler, P., and M. Mata-Gilsinger. 1982. Use of in vitro gene fusions to study the uxuR regulatory gene in Escherichia coli K-12: direction of transcription and regulation of its expression. J. Bacteriol. 150:1040–1047.

711. Ritzenthaler, P., M. Mata-Gilsinger, and F. Stoeber. 1980. Construction and expression of hybrid plasmids containing Escherichia coli K-12 uxu genes. J. Bacteriol. 143:1116–1126.

712. Ritzenthaler, P., M. Mata-Gilsinger, and F. Stoeber. 1981. Molecular cloning of the Escherichia coli K-12 hexuronate system genes: the exu region. J. Bacteriol. 145:181–190.

713. Robbins, A. R. 1975. Regulation of the Escherichia coli methylgalactoside transport system by gene mglD. J. Bacteriol. 123:69–74.

714. Robbins, A. R., R. Guzman, and B. Rotman. 1976. Roles of individual mgl gene products in the beta-methylgalactoside transport system of Escherichia coli K12. J. Biol. Chem. 251:3112–3116.

715. Robbins, A. R., and B. Rotman. 1975. Evidence for binding protein-independent substrate translocation by the methylgalactoside transport system of Escherichia coli. Proc. Natl. Acad. Sci. USA 72:423–427.

716. Robert-Baudouy, J., J. Jimeno-Abendano, and F. Stoeber. 1971. Individualité des hydro-lyases mannonique et altronique chez Escherichia coli K-12. C.R. Acad. Sci. Ser. D. 272:2740–2743.

717. Robert-Baudouy, J., R. Portalier, and F. Stoeber. 1974. Régulation du metabolisme des hexuronates chez Escherichia coli K-12: modalités de l’induction des enzymes du système hexuronate. Eur. J. Biochem. 43:1–15.

718. Robert-Baudouy, J., and F. Stoeber. 1981. Regulation of hexuronate system genes in Escherichia coli K-12: multiple regulation of the uxu operon by exuR and uxuR gene products. J. Bacteriol. 145:211–220.

719. Robert-Baudouy, J., and F. Stoeber. 1973. Purification et propriétés de la d-mannonate hydrolyase d’Escherichia coli K 12. Biochim. Biophys. Acta 309:473–485.

720. Robert-Baudouy, J. M., J. M. Jimeno-Abendano, and F. R. Stoeber. 1975. Individualité des hydrolyases mannonique et altronique chez Escherichia coli K-12. Biochimie 57:1–8.

721. Robert-Baudouy, J. M., and R. C. Portalier. 1974. Studies of mutations in glucuronate catabolism in Escherichia coli K-12. Mol. Gen. Genet. 131:31–46.

722. Robert-Baudouy, J. M., R. C. Portalier, and F. R. Stober. 1972. Genetic mapping and biochemical characterization of mutations in the mannonic hydrolyase structural gene of Escherichia coli K-12. Mol. Gen. Genet. 118:351–362.

723. Roberts, R. B., and I. Z. Roberts. 1950. Potassium metabolism in Escherichia coli. III. Interrelationship of potassium and phosphorus metabolism. J. Cell. Comp. Physiol. 36:15–39.

724. Robertson, B. C., and P. A. Hoffee. 1973. Purification and properties of purine nucleoside phosphorylase from Salmonella typhimurium. J. Biol. Chem. 248:2040–2043.

725. Robertson, B. C., P. Jargiello, J. Blank, and P. A. Hoffee. 1970. Genetic regulation of ribonucleoside and deoxyribonucleoside catabolism in Salmonella typhimurium. J. Bacteriol. 102:628–635.

726. Robinson, J. J., and J. H. Weiner. 1980. The effect of amphipaths on the flavin-linked aerobic glycerol-3-phosphate dehydrogenase from Escherichia coli. Can. J. Biochem. 80:1172–1178.

727. Rolseth, S., V. Fried, and B. G. Hall. 1980. A mutant ebg enzyme that converts lactose into an inducer of the lac operon. J. Bacteriol. 142:1036–1039.

728. Roossien, F. F., M. Blaauw, and G. T. Robillard. 1984. Kinetics and subunit interaction of the mannitol-specific enzyme II of the Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system. Biochemistry 23:4934–4939.

729. Roossien, F. F., and G. T. Robillard. 1984. Vicinal dithiol-disulfide distribution in the Escherichia coli mannitol specific carrier enzyme II Mtl. Biochemistry 23:211–215.

730. Roossien, F. F., and G. T. Robillard. 1984. Mannitol-specific carrier protein from the Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system can be extracted as a dimer from the membrane. Biochemistry 23:5682–5685.

731. Ros, J., and J. Aguilar. 1984. Genetic and structural evidence for the presence of propanediol oxidoreductase isoenzymes in Escherichia coli. J. Gen. Microbiol. 130:687–692.

732. Rose, S. P., and C. F. Fox. 1971. The beta-glucoside system of Escherichia coli. II. Kinetic evidence for a phosphoryl-enzyme II intermediate. Biochem. Biophys. Res. Commun. 45:376–380.

733. Rosen, S. M., L. D. Zeleznick, D. Fraenkel, I. M. Weiner, M. J. Osborn, and B. L. Horecker. 1965. Characterization of the cell wall lipopolysaccharide of a mutant Salmonella typhimurium lacking phosphomannose isomerase. Biochem. Z. 342:375–386.

734. Rosenberg, H., and C. M. Hardy. 1984. Conversion of d-mannitol to d-ribose: a newly discovered pathway in Escherichia coli. J. Bacteriol. 158:69–72.

735. Rosenberg, H., S. M. Pearce, C. M. Hardy, and P. A. Jacomb. 1984. Rapid turnover of mannitol-1-phosphate in Escherichia coli. J. Bacteriol. 158:63–68.

736. Rosenfeld, S. A., P. E. Stevis, and N. W. Y. Ho. 1984. Cloning and characterization of the xyl genes from Escherichia coli. Mol. Gen. Genet. 194:410–415.

737. Ross, J. P., and C. W. Shuster. 1972. Amino sugar assimilation by Escherichia coli. J. Bacteriol. 112:894–902.

738. Rotman, B. 1959. Separate permeases for the accumulation of methyl-beta-d-galactoside and methyl-beta-d-thiogalactoside in Escherichia coli. Biochim. Biophys. Acta 32:599–601.

739. Rotman, B., A. K. Ganesan, and R. Guzman. 1968. Transport systems for galactose and galactosides in Escherichia coli. II. Substrate and inducer specificities. J. Mol. Biol. 36:247–260.

739a. Rotman, B., and R. Guzman. 1961. Transport of galactose from the inside to the outside of Escherichia coli. Pathol. Biol. 9:806–810.

740. Rotman, B., and R. Guzman. 1982. Identification of the mglA gene product in the beta-methylgalactoside transport system of Escherichia coli using plasmid DNA deletions generated in vitro. J. Biol. Chem. 257:9030–9034.

741. Rotman, B., and R. Guzman. 1984. Galactose-binding protein-dependent transport in reconstituted Escherichia coli membrane vesicles, p. 57–60. In L. Leive and D. Schlessinger (ed.), Microbiology—1984. American Society for Microbiology, Washington, D.C.

742. Rotman, B., and J. Radojkovic. 1964. Galactose transport in Escherichia coli. The mechanism underlying the retention of intracellular galactose. J. Biol. Chem. 239:3153–3156.

743. Roy-Burman, S., and D. W. Visser. 1972. Transport studies of showdomycin, nucleosides and sugars in Escherichia coli B and showdomycin-resistant mutants. Biochim. Biophys. Acta 282:383–392.

744. Roy-Burman, S., and D. W. Visser. 1975. Transport of purines and deoxyadenosine in Escherichia coli. J. Biol. Chem. 250:9270–9275.

745. Roy-Burman, S., and D. W. Visser. 1981. Uridine and uracil transport in Escherichia coli and transport-deficient mutants. Biochim. Biophys. Acta 646:309–319.

746. Roy-Burman, S., P. J. von Dipper, and D. W. Visser. 1978. Mechanism of energy coupling for transport of deoxycytidine, uridine, uracil, adenine and hypoxanthine in Escherichia coli. Biochim. Biophys. Acta 511:285–296.

747. Ruiz-Vasquez, R., C. Pueyo, and E. Cerda-Olmeda. 1978. A mutagen assay detecting forward mutations in an arabinose-sensitive strain of Salmonella typhimurium. Mutat. Res. 54:121–129.

747a. Russo, R. J., J.-M., Lee, P. Clarke, and G. Wilcox. 1984. Identification of the araE gene product of Salmonella typhimurium LT2, p. 42–46. In L. Leive and D. Schlessinger (ed.), Microbiology—1984. American Society for Microbiology, Washington, D.C.

748. Saedler, H., A. Gullon, L. Flethen, and P. Starlinger. 1968. Negative control of the galactose operon in Escherichia coli. Mol. Gen. Genet. 102:79–88.

749. Saier, M. H., Jr., F. G. Bromberg, and S. Roseman. 1973. Characterization of constitutive galactose permease mutants in Salmonella typhimurium. J. Bacteriol. 113:512–523.

750. Saier, M. H., Jr., F. C. Grenier, C. A. Lee, and E. B. Waygood. 1985. Evidence for the evolutionary relatedness of the proteins of the bacterial phosphoenolpyruvate:sugar phosphotransferase system. J. Cell. Biochem. 27:43–56.

751. Saier, M. H., Jr., and M. J. Newman. 1976. Direct transfer of the phosphoryl moiety of mannitol 1-phosphate to [¹⁴C] mannitol catalyzed by the enzyme II complexes of the phosphoenolpyruvate:mannitol phosphotransferase systems in Spirochaeta aurantia and Salmonella typhimurium. J. Biol. Chem. 251:3834–3837.

752. Saier, M. H., Jr., and S. Roseman. 1976. Sugar transport. Inducer exclusion and regulation of the melibiose, maltose, glycerol, and lactose transport systems by the phosphoenolpyruvate:sugar phosphotransferase system. J. Biol. Chem. 251:6606–6615.

753. Saier, M. H., Jr., H. Straud, L. S. Massman, J. J. Judice, M. J. Newman, and B. U. Fecht. 1978. Permease-specific mutations in Salmonella typhimurium and Escherichia coli that release the glycerol, maltose, melibiose, and lactose transport systems from regulation by the phosphoenolpyruvate:sugar phosphotransferase system. J. Bacteriol. 133:1358–1367.

754. Saier, M. H., Jr., D. L. Wentzel, B. U. Feucht, and J. J. Judice. 1975. A transport system for phosphoenolpyruvate, 2-phosphoglycerate, and 3-phosphoglycerate in Salmonella typhimurium. J. Biol. Chem. 250:5089–5096.

755. Saint Pierre, M. L. 1968. Isolation and mapping of Salmonella typhimurium mutants defective in the utilization of trehalose. J. Bacteriol. 95:1185–1186.

756. Sanderson, K. E. 1972. Linkage map of Salmonella typhimurium, edition IV. Bacteriol. Rev. 36:558–586.

757. Sanderson, K. E., and P. E. Hartman. 1978. Linkage map of Salmonella typhimurium , edition V. Microbiol. Rev. 42:471–519.

758. Sanderson, K. E., and J. R. Roth. 1983. Linkage map of Salmonella typhimurium, edition VI. Microbiol. Rev. 47:410–453.

759. Sanno, Y., T. H. Wilson, and E. C. C. Lin. 1968. Control of permeation to glycerol in cells of Escherichia coli. Biochem. Biophys. Res. Commun. 32:344–349.

760. Sarno, M. V., L. G. Tenn, A. Desai, A. M. Chin, F. C. Grenier, and M. H. Saier, Jr. 1984. Genetic evidence for glucitol-specific enzyme III, an essential phosphocarrier protein of the Salmonella typhimurium glucitol phosphotransferase system. J. Bacteriol. 157:953–955.

761. Sarvas, M. 1971. Mutant of Escherichia coli K-12 defective in d-glucosamine biosynthesis. J. Bacteriol. 105:467–471.

762. Sawada, H., and Y. Takagi. 1964. The metabolism of l-rhamnose in Escherichia coli. III. l-Rhamnulose-phosphate aldolase. Biochim. Bioiphys. Acta 92:26–32.

763. Scangos, G. A., and A. M. Reiner. 1978. Acquisition of ability to utilize xylitol: disadvantage of a constitutive catabolic pathway in Escherichia coli. J. Bacteriol. 134:501–505.

764. Scangos, G. A., and A. M. Reiner. 1978. Ribitol and d-arabitol catabolism in Escherichia coli. J. Bacteriol. 134:492–500.

765. Scangos, G. A., and A. M. Reiner. 1979. A unique pattern of toxic synthesis in pentitol catabolism: implications for evolution. J. Mol. Evol. 12:189–195.

766. Schächtele, K.-H., E. Schiltz, and D. Palm. 1978. Amino acid sequence of the pyridoxal phosphate binding site in Escherichia coli maltodextrin phosphorylase. Eur. J. Biochem. 92:427–435.

767. Schaefler, S. 1967. Inducible system for the utilization of beta-glucosides in Escherichia coli. I. Active transport and utilization of beta-glucosides. J. Bacteriol. 93:254–263.

768. Schaefler, S., and W. K. Maas. 1967. Inducible system for the utilization of beta-glucosides in Escherichia coli. II. Description of mutant types and genetic analysis. J. Bacteriol. 93:264–272.

769. Schaefler, S., and A. Malamy. 1969. Taxonomic investigations on expressed and cryptic phospho-beta-glucosidases in Enterobacteriaceae. J. Bacteriol. 99:422–433.

770. Schäfler, S., and L. Mintzer. 1959. Acquisition of lactose fermenting properties by Salmonellae. I. Interrelationship between the fermentation of cellobiose and lactose. J. Bacteriol. 78:159–163.

771. Schellenberg, G. D., A. Sarthy, A. E. Larson, M. P. Backer, J. W. Crabb, M. Lidstrom, B. D. Hall, and C. E. Furlong. 1984. Xylose isomerase from Escherichia coli. Characterization of the protein and the structural gene. J. Biol. Chem. 259:6826–6832.

772. Schleif, R. 1969. An inducible l-arabinose binding protein and arabinose permeation in Escherichia coli. J. Mol. Biol. 46:185–196.

773. Schmid, K., and R. Schmitt. 1976. Raffinose metabolism in Escherichia coli K12: purification and properties of a new alpha-galactosidase specified by a transmissible plasmid. Eur. J. Biochem. 67:94–104.

774. Schmid, K., M. Schupfner, and R. Schmitt. 1982. Plasmid-mediated uptake and metabolism of sucrose by Escherichia coli K-12. J. Bacteriol. 151:68–76.

775. Schmitt, R. 1968. Analysis of melibiose mutants deficient in alpha-galactosidase and thiomethylgalactoside permease II in Escherichia coli K-12. J. Bacteriol. 96:461–471.

776. Schmitt, R., and B. Rotman. 1966. Alpha-galactosidase activity in cell-free extracts of Escherichia coli. Biochem. Biophys. Res. Commun. 22:473–479.

777. Schryvers, A., E. Lohmeier, and J. H. Weiner. 1978. Chemical and functional properties of the native and reconstituted forms of the membrane-bound, aerobic glycerol-3-phosphate dehydrogenase of Escherichia coli. J. Biol. Chem. 253:783–788.

778. Schryvers, A., and J. H. Weiner. 1981. The anaerobic sn-glycerol-3-phosphate dehydrogenase of Escherichia coli. J. Biol. Chem. 256:9959–9965.

779. Schryvers, A., and J. H. Weiner. 1982. The anaerobic sn-glycerol-3-phosphate dehydrogenase: cloning and expression of the glpA gene of Escherichia coli and identification of the glpA products. Can. J. Biochem. 60:224–231.

780. Schulz, G. V., V. Häselbarth, H. E. Keller, and H. A. Schwinn. 1966. Das Durch das Enzym Amylomaltase eingestellte Gleichgewicht oligomerer Amylosen. Makromol. Chem. 92:91–104.

781. Schumacher, G., and K. Bussmann. 1978. Cell-free synthesis of proteins related to sn-glycerol-3-phosphate transport in Escherichia coli. J. Bacteriol. 135:239–250.

782. Schwartz, M. 1967. Sur l’éxistence chez Escherichia coli K12 d’une regulation commune a la biosynthèse des recepteurs des bacteriophage lambda et au metabolisme du maltose. Ann. Inst. Pasteur (Paris) 113:685–704.

783. Schwartz, M. 1971. Thymidine phosphorylase from Escherichia coli. Eur. J. Biochem. 21:191–198.

784. Schwartz, M. 1975. Reversible interaction between coliphage lambda and its receptor protein. J. Mol. Biol. 99:185–201.

785. Schwartz, M. 1978. Thymidine phosphorylase from Escherichia coli. Methods Enzymol. 51:442–445.

786. Schwartz, M., and M. Hofnung. 1962. La maltodextrine phosphorylase d’Escherichia coli. Eur. J. Biochem. 2:132–145.

787. Schwartz, M., and L. LeMinor. 1975. Occurrence of the bacteriophage lambda receptor in some Enterobacteriaceae. J. Virol. 15:679–685.

788. Schwartz, N. B., and D. S. Feingold. 1972. l-Rhamnulose 1-phosphate aldolase from Escherichia coli. III. The role of divalent cations in enzyme activity. Bioinorg. Chem. 2:75–86.

789. Schweizer, H., M. Argast, and W. Boos. 1982. Characteristics of a binding protein-dependent transport system for sn-glycerol-3-phosphate in Escherichia coli that is part of the pho regulon. J. Bacteriol. 150:1154–1163.

790. Schweizer, H., W. Boos, and T. J. Larson. 1985. Repressor for the sn-glycerol-3-phosphate regulon of Escherichia coli: cloning of the glpR gene and identification of its product. J. Bacteriol. 161:563–566.

791. Schwinn, H., and G. V. Schulz. 1971. Untersuchungen über Amylomaltose. III. Kinetische Analyse des Reaktions mechanismus. Biochim. Biophys. Acta 227:313–326.

792. Scripture. J. B., and R. W. Hogg. 1983. The nucleotide sequences defining the signal peptides of the galactose-binding protein and the arabinose-binding protein. J. Biol. Chem. 258:10853–10855.

793. Schamanna, D. K., and K. E. Sanderson. 1979. Uptake and catabolism of d-xylose in Salmonella typhimurium LT2. J. Bacteriol. 139:64–70.

794. Shamanna, D. K., and K. E. Sanderson. 1979. Genetics and regulation of d-xylose utilization in Salmonella typhimurium LT2. J. Bacteriol. 139:71–79.

795. Shapiro, J. A. 1966. Chromosomal locations of the gene determining uridine diphosphoglucose formation in Escherichia coli K-12. J. Bacteriol. 92:518–520.

795a. Shapiro, J. A., and S. L. Adhya. 1969. The galactose operon of E. coli K-12. II. A deletion analysis of operon structure and polarity. Genetics 62:249–264.

796. Shattuck-Eidens, D. M., and R. J. Kadner. 1981. Exogenous induction of the Escherichia coli hexose phosphate transport system defined by uhp-lac operon fusions. J. Bacteriol. 148:203–209.

797. Shattuck-Eidens, D. M., and R. J. Kadner. 1983. Molecular cloning of the uhp region and evidence for a positive activator for expression of the hexose phosphate transport system of Escherichia coli. J. Bacteriol. 155:1062–1070.

798. Shedlovsky, A., and S. Brenner. 1963. A chemical basis for the host-induced modification of T-even bacteriophages. Proc. Natl. Acad. Sci. USA 50:300–305.

799. Sheinin, R., and B. F. Crocker. 1961. The induced concurrent formation of alpha-galactosidase and beta-galactosidase in Escherichia coli B. Can. J. Biochem. Physiol. 39:63–72.

800. Sherman, J. R., and J. Adler. 1963. Galactokinase from Escherichia coli. J. Biol. Chem. 238:873–878.

801. Shiota, S., H. Yazyu, and T. Tsuchiya. 1984. Escherichia coli mutants with altered cation recognition by the melibiose carrier. J. Bacteriol. 160:445–447.

802. Shiota, S., Y. Yamano, M. Futal, and T. Tsuchiya. 1985. Escherichia coli mutants possessing an Li⁺-resistant melibiose carrier. J. Bacteriol. 162:106–109.

803. Shopsis, C. S., R. Engel, and B. E. Tropp. 1972. Effects of phosphonic acid analogues of glycerol-3-phosphate on the growth of Escherichia coli. J. Bacteriol. 112:408–412.

804. Shopsis, C. S., W. D. Nunn, R. Engel, and B. E. Tropp. 1973. Effects of phosphonic acid analogues of glycerol-3-phosphate on the growth of Escherichia coli: phospholipid metabolism. Antimicrob. Agents Chemother. 4:467–473.

805. Short, S. A., and J. T. Singer. 1984. Studies on deo operon regulation in Escherichia coli: cloning and expression of the deoR structural gene. Gene 31:205–211.

806. Shuman, H. A. 1982. Active transport of maltose in Escherichia coli K12: role of the periplasmic maltose-binding protein and evidence for a substrate recognition site in the cytoplasmic membrane. J. Biol. Chem. 257:5455–5461.

807. Shuman, H. A., and J. Beckwith. 1979. Escherichia coli K-12 mutants that allow transport of maltose via the beta-galactoside transport system. J. Bacteriol. 137:365–373.

808. Shuman, H. A., and T. J. Silhavy. 1981. Identification of the malK gene product: a peripheral membrane component of the Escherichia coli maltose transport system. J. Biol. Chem. 256:560–562.

809. Shuman, H. A., T. J. Silhavy, and J. Beckwith. 1980. Labeling of proteins with beta-galactosidase by gene fusion. Identification of a cytoplasmic membrane component of the Escherichia coli maltose transport system. J. Biol. Chem. 255:168–174.

810. Shuman, H. A., and N. A. Treptow. 1985. The maltose-malto-dextrin-transport system of Escherichia coli K-12, p. 562–575. In A. N. Martonosi (ed.), The Enzymes of Biological Membranes, 2nd ed., vol. 3. Plenum Publishing Co., New York.

811. Shuster, C. W., and K. Randell. 1969. Resistance of Salmonella typhimurium mutants to galactose death. J. Bacteriol. 100:103–109.

812. Silhavy, T. J., I. Hartig-Beecken, and W. Boos. 1976. Periplasmic protein related to the sn-glycerol-3-phosphate transport system of Escherichia coli. J. Bacteriol. 126:951–958.

813. Singer, J. T., C. S. Barbier, and S. Short. 1985. Identification of the Escherichia coli deoR and cytR gene products. J. Bacteriol. 63:1095–1100.

814. Singh, A. P., and P. D. Bragg. 1976. Anaerobic transport of amino acids coupled to the glycerol-3-phosphate-fumarate oxidoreductase system in a cytochrome-deficient mutant of Escherichia coli. Biochim. Biophys. Acta 423:450–461.

815. Skjold, A. C., and D. H. Ezekiel. 1982. Analysis of lambda insertions in the fucose utilization region of Escherichia coli K-12: use of lambda fuc and lamba argA transducing bacteriophages to partially order the fucose utilization genes. J. Bacteriol. 152:120–125.

816. Skjold, A. C., and D. H. Ezekiel. 1982. Regulation of d-arabinose utilization in Escherichia coli K-12. J. Bacteriol. 152:521–523.

817. Slater, A. C., M. C. Jones-Mortimer, and H. L. Kornberg. 1981. l-Sorbose phosphorylation in Escherichia coli K-12. Biochim. Biophys. Acta 646:365–367.

818. Smiley, J. D., and G. Ashwell. 1960. Uronic acid metabolism in bacteria. III. Purification and properties of d-altronic acid and d-mannonic acid dehydrases in Escherichia coli. J. Biol. Chem. 235:1517–1519.

819. Smith, H. W., and Z. Parsell. 1975. Transmissible substrate-utilizing ability in enterobacteria. J. Gen. Microbiol. 87:129–140.

820. Soffer, R. L. 1961. Enzymatic expression of genetic units of function concerned with galactose metabolism in Escherichia coli. J. Bacteriol. 82:471–478.

821. Solomon, E., and E. C. C. Lin. 1972. Mutations affecting the dissimilation of mannitol by Escherichia coli K-12. J. Bacteriol. 111:566–574.

822. Sprenger, G. A., and J. W. Lengeler. 1984. l-Sorbose metabolism in Klebsiella pneumoniae and Sor⁺ derivatives of Escherichia coli K-12 and chemotaxis toward sorbose. J. Bacteriol. 157:39–45.

823. Sridhara, S., and T. T. Wu. 1969. Purification and properties of lactaldehyde dehydrogenase in Escherichia coli. J. Biol. Chem. 244:5233–5238.

824. Sridhara, S., T. T. Wu, T. M. Chused, and E. C. C. Lin. 1969. Ferrous-activated nicotinamide adenine dinucleotide-linked dehydrogenase from a mutant of Escherichia coli capable of growth on 1,2-propanediol. J. Bacteriol. 98:87–95.

825. Stephenson, M., and A. R. Trim. 1938. The metabolism of adenine compounds by Bact. coli. Biochem. J. 32:1740–1751.

826. Stevens, F. J., and T.-T. Wu. 1976. Growth on d-xylose of a mutant strain of Escherichia coli K12 using a novel isomerase and enzymes related to d-xylase metabolism. J. Gen. Microbiol. 97:257–265.

827. St. Martin, E. J. W. B. Freedberg, and E. C. C. Lin. 1977. Kinase replacement by a dehydrogenase for Escherichia coli glycerol utilization. J. Bacteriol. 131:1026–1028.

828. Stock, J., and S. Roseman. 1971. A sodium-dependent sugar co-transport system in bacteria. Biochem. Biophys. Res. Commun. 44:132–138.

829. Stoeber, F. 1957. Sur la beta-glucuronide-permease d’Escherichia coli. C.R. Acad. Sci. Ser. D 244:1091–1094.

830. Stoeber, F., A. Lagarde, G. Nemoz, G. Novel, M. Novel, R. Portalier, J. Pouyssegur, and J. Robert-Baudouy. 1974. Le métabolisme des hexuronides et des hexuronates chez Escherichia coli K-12: aspects physiologiques et génétiques de sa régulation. Biochimie 56:199–213.

831. Stokes, H. W., P. W. Betts, and B. G. Hall. 1985. Sequence of the ebgA gene of Escherichia coli: comparison with the lacZ gene. Mol. Biol. Evol. 2:469–477.

832. Stokes, H. W., and B. G. Hall. 1985. Sequence of the ebgR gene of Escherichia coli: evidence that the EBG and LAC operons are descended from a common ancestor. Mol. Biol. Evol. 2:478–483.

833. Strange, P. G., and D. E. Koshland, Jr. 1986. Receptor interactions in a signalling system: competition between ribose receptor and galactose receptor in the chemotaxis response. Proc. Natl. Acad. Sci. USa 73:762–766.

834. Sukhodoletz, V. V., V. P. Galeys, and Y. V. Smirnov. 1973. The nature of phenotypical reversions of mutants for thymidine phosphorylase in Escherichia coli. Genetika 9:167–169.

835. Sundaram, T. K. 1972. Myo-inositol catabolism in Salmonella typhimurium: enzyme repression dependent on growth history of organism. J. Gen. Microbiol. 73:209–219.

835a. Sundararajan, T. A. 1963. Interference with glycerolkinase induction in mutants of E. coli accumulating GAL-1-P. Biochemistry 50:463–469.

836. Sundararajan, T. A., A. M. C. Rapin, and H. M. Kalckar. 1962. Biochemical observations on E. coli mutants defective in uridine diphosphoglucose. Proc. Natl. Acad. Sci. USA 48:2187–2193.

837. Svenningsen, B.A. 1975. Regulated in vitro synthesis of enzymes of deo operon of Escherichia coli: properties of DNA directed system. Mol. Gen. Genet. 137:289–304.

838. Svenningsen, B. A. 1977. In vitro regulation of the deo operon of Escherichia coli at the initiation of transcription. Carlsberg Res. Commun. 42:517–524.

839. Synenki, R. M., J. A. Wohlhieter, E. M. Johnson, J. R. Lazere, and L. S. Baron. 1973. Isolation and characterization of circular deoxyribonucleic acid obtained from lactose-fermenting Salmonella strains. J. Bacteriol. 116:1185–1190.

840. Szmelcman, S., and M. Hofnung. 1975. Maltose transport in Escherichia coli: involvement of the bacteriophage lambda receptor. J. Bacteriol. 124:112–118.

841. Szmelcman, S., M. Schwartz, T. J. Silhavy, and W. Boos. 1976. Maltose transport in Escherichia coli K12. A comparison of transport kinetics in wild type and lambda-resistant mutants with the dissociation constants of the maltose-binding protein as measured by fluorescence quenching. Eur. J. Biochem. 65:13–19.

842. Takagi, Y., M. Kanda, and Y. Nakata. 1959. Studies on a d-galacturonic acid isomerase. Biochim. Biophys. Acta 31:264–265.

843. Takagi, Y., and H. Sawada. 1964. The metabolism of l-rhamnose in Escherichia coli. I. l-Rhamnose isomerase. Biochim. Biophys. Acta 92:10–17.

844. Takagi, Y., and H. Sawada. 1964. The metabolism of l-rhamnose in Escherichia coli. II. l-Rhamnulose kinase. Biochim. Biophys. Acta 92:18–25.

845. Taketo, A., and S. Kuno. 1972. Internal localization of nucleoside-catabolic enzymes in Escherichia coli. J. Biochem. 72:1557–1563.

846. Tanaka, K., S. Niliya, and T. Tsuchiya. 1980. Melibioise transport in Escherichia coli. J. Bacteriol. 141:1031–1036.

847. Tang, C.-T., R. Engel, and B. E. Tropp. 1977. l-Glycerol 3-phosphate, a bactericidal agent. Antimicrob. Agents Chemother. 11:147–153.

848. Tang, C.-T., F. E. Ruch, Jr., and E. C. C. Lin. 1979. Purification and properties of a nicotinamide adenine dinucleotide-linked dehydrogenase that serves an Escherichia coli mutant for glycerol catabolism. J. Bacteriol. 140:182–187.

849. Tang, J. C.-T., R. G. Forage, and E. C. C. Lin. 1982. Immunochemical properties of NAD⁺-linked glycerol dehydrogenases from Escherichia coli and Klebsiella pneumoniae. J. Bacteriol. 152:1169–1174.

850. Tang, J. C.-T., E. J. St. Martin, and E. C. C. Lin. 1982. Derepression of an NAD-linked dehydrogenase that serves an Escherichia coli mutant for growth on glycerol. J. Bacteriol. 152:1001–1007.

851. Taniguchi, T., M. O’Neill, and B. de Crombrugghe. 1979. Interaction site of Escherichia coli cyclic AMP receptor protein on DNA of galactose operon promoters. Proc. Natl. Acad. Sci. USA 76:5090–5094.

852. Taylor, A. L., and M. S. Thoman. 1964. The genetic map of Escherichia coli K-12. Genetics 50:659–677.

853. Thanner, F., D. Palm, and S. Shaltiel. 1974. Hydrophobic and biiospecific chromatography in the purification of maltodextrin phosphorylase from E. coli. FEBS Lett. 55:178–182.

854. Thirion, J. P., and M. Hofnung. 1972. On some genetic aspects of phage lambda resistance in E. coli K12. Genetics 71:207–216.

855. Thorner, J. W., and H. Paulus. 1971. Composition and subunit structure of glycerol kinase from Escherichia coli. J. Biol. Chem. 246:3885–2894.

856. Thorner, J. W., and H. Paulus. 1973. Catalytic and allosteric properties of glycerol kinase from Escherichia coli. J. Biol. Chem. 248:3922–3932.

857. Thorner, J. W., and H. Paulus. 1973. Glycerol and glycerate kinases, p. 487–508. In P. D. Boyer (ed.), The Enzymes. Academic Press, Inc., New York.

858. Tokuda, H., and H. R. Kaback. 1977. Sodium-dependent methyl 1-thio-beta-d-galactopyranoside transport in membrane vesicles isolated from Salmonella typhimurium. Biochemistry 16:2130–2136.

859. Torriani, A. M., and J. Monod. 1949. Sur la reversibilité de la réaction catalysée par l’amylomaltase. C.R. Acad. Sci. Ser. D 228:718–720.

860. Trisler, P., and S. Gottesman. 1984. Ion transcriptional regulation of genes necessary for capsular polysaccharide synthesis in Escherichia coli K-12. J. Bacteriol. 160:184–191.

861. Tsuchlya, T., J. Lopilato, and T. H. Wilson. 1978. Effect of lithium ion on melibiose transport in Escherichia coli. J. Membr. Biol. 42:45–59.

862. Tsuchlya, T., M. Oho, and S. Shiota-Nilya. 1983. Lithium ion-sugar cotransport via the melibiose transport system in Escherichia coli. J. Biol. Chem. 258:12765–12767.

863. Tsuchiya, T., K. Ottina, Y. Moriyama, M. J. Newmann, and T. H. Wilson. 1982. Solubilization and reconstitution of the melibiose carrier from a plasmid-carrying strain of Escherichia coli. J. Biol. Chem. 257:5125–5128.

864. Tsuchiya, T., J. Raven, and T. H. Wilson. 1977. Co-transport of Na⁺ and methyl-beta-d-thiogalactopyranoside mediated by the melibiose transport system of Escherichia coli. Biochem. Biophys. Res. Commun. 76:26–31.

865. Tsuchiya, T., K. Takeda, and T. H. Wilson. 1980. H⁺ substrate cotransport by the melibiose membrane carrier in Escherichia coli. Membr. Biochem. 3:131–146.

866. Tsuchiya, T., and T. H. Wilson. 1978. Cation-sugar cotransport in the melibiose transport system of Escherichia coli. Membr. Biochem. 2:63–79.

867. Valentin-Hansen, P. 1982. Tandem CRP binding sites on the deo operon of Escherichia coli K-12. EMBO J. 1:1049–1054.

868. Valentin-Hansen, P., H. Alba, and D. Schümperlin. 1982. The structure of tandem regulatory regions in the deo operon of Escherichia coli K-12. EMBO J. 1:310–322.

869. Valentin-Hansen, P., F. Boetius, K. Hammer-Jespersen, and I. Svendsen. 1982. The primary structure of Escherichia coli K 12 2-deoxyribose 5-phosphate aldolase. Nucleotide sequence of the deoC gene and the amino acid sequence of the enzyme. Eur. J. Biochem. 125:561–566.

870. Valentin-Hansen, P., K. Hammer-Jespersen, F. Boetius, and I. Svendsen. 1984. Structure and function of the intercistronic regulatory deoC-deoA element of Escherichia coli K-12. EMBO J. 3:179–183.

871. Valentin-Hansen, P., K. Hammer-Jespersen, and R. S. Buxton. 1979. Evidence for the existence of three promoters for the deo operon of Escherichia coli K12 in vitro. J. Mol. Biol. 133:1–17.

872. Valentin-Hansen, P., B. Svenningsen, A. Munch-Petersen, and K. Hammer-Jespersen. 1978. Regulation of the deo operon in Escherichia coli. Mol. Gen. Genet. 159:191–202.

873. van Thienen, G. M., P. W. Postma, and K. Van Dam. 1977. Proton movements coupled to sugar transport via the galactose transport system in Salmonella typhimurium. Eur. J. Biochem. 73:521–527.

874. Venkateswaran, P. S., and H. C. Wilson. 1972. Isolated and characterization of a phosphonomycin resistant mutant in Escherichia coli K-12. J. Bacteriol. 110:904–944.

875. von Dippe, P. J., K.-K. Lening, S. Roy-Burman, and D. W. Visser. 1975. Deoxycytidine transport in the presence of cytidine deaminase inhibitor and the transport of uracil in Escherichia coli B. J. Biol. Chem. 250:3666–3671.

876. von Dippe, P. J., S. Roy-Burman, and D. W. Visser. 1973. Transport of uridine in Escherichia coli B and a showdomycin-resistant mutant. Biochim. Biophys. Acta 318:105–112.

877. von Hofsten, B. 1961. The inhibitory effect of galactosides on the growth of Escherichia coli. Biochim. Biophys. Acta 48:164–171.

878. von Meyenburg, K., F. G. Hanse, L. D. Nielsen, and P. Jørgensen. 1977. Origin of replication, oriC, of the Escherichia coli chromosome: mapping of genes relative to R. EcoRI cleavage sites in the oriC region. Mol. Gen. Genet. 158:101–109.

879. von Meyenburg, K., F. G. Hansen, L. D. Nielsen, and E. Rilse. 1978. Origin of replication, oriC, of the Escherichia coli chromosome on specialized transducing phages lambda asn. Mol. Gen. Genet. 160:287–295.

880. von Meyenburg, K., and H. Nikaido. 1977. Outer membrane of gram-negative bacteria. XVII. Specificity of transport process catalysed by the lambda-receptor protein in Escherichia coli. Biochem. Biophys. Res. Commun. 78:1100–1107.

881. von Wilcken-Bergmann, B., and B. Müller-Hill. 1982. Sequence of galR gene indicates a common evolutionary origin of lac and gal repressor in Escherichia coli. Proc. Natl. Acad. Sci. USA 79:2427–2431.

882. Vorisek, J., and A. Kepes. 1972. Galactose transport in Escherichia and the galactose-binding protein. Eur. J. Biochem. 79:2427–2431.

883. Vyas, N. K., M. N. Vyas, and F. A. Quiocho. 1983. The 3Å resolution structure of a d-galactose-binding protein for transport and chemotaxis in Escherichia coli. Proc. Natl. Acad. Sci. USA 80:1792–1796.

884. Wahba A. J., J. W. Hickman, and G. Ashwell. 1958. Enzymatic formation of d-tagaturonic acid and d-fructuronic acid. J. Am. Chem. Soc. 80:2594–2595.

885. Wallenfels, K., J. Lehman, and O. P. Malhotra. 1960. Untersuchungen über milchzuckerspaltende Enzyme. VII. Die Specifität der B-Galakosidase von E. coli ML 309. Biochem. Z. 333:209–225.

886. Wallenfels, K., O. P. Malhotra, and D. Dabich. 1960. Untersuchungen über milchzuckerspaltende Enzyme. VIII. Der Einfluss des Kationen-Milieus auf die Aktivität der β-Galactosidase von E. coli ML 309. Biochem. Z. 333:377–394.

887. Wallenfels, K., and R. Well. 1972. Beta-galactosidase, p. 617–663. In P. D. Boyer (ed.), The Enzymes, 3rd ed., vol. 7. Academic Press, Inc., New York.

888. Wallenfels, K., M. L. Zarnitz, G. Laude, H. Bender, and M. Keser. 1959. Untersuchungen über milchzuckerspaltende Enzyme. III. Reinigung, Kristallisation and Eigenschafter der beta-Galaktosidase von Escherichia coli ML 309. Biochem. Z. 331:459–485.

889. Wandersman, C., M. Schwartz, and T. Ferenci. 1979. Mutants of Escherichia coli impaired in the transport of maltodextrins. J. Bacteriol. 140:1–13.

890. Wang, T. P., H. Z. Sable, and J. O. Lampon. 1950. Enzymatic deamination of cytosine nucleosides. J. Biol. Chem. 184:17–28.

891. Waygood, E. B. 1980. Resolution of the phosphoenolpyruvate:fructose phosphotransferase system of Escherichia coli into two components; enzyme II fructose and fructose-induced HPr-like protein (FPr). Can. J. Biochem. 58:1144–1146.

892. Waygood, E. B., R. L. Mattoo, and K. G. Peri. 1984. Phosphoproteins and the phosphoenolpyruvate:sugar phosphotransferase system in Salmonella typhimurium and Escherichia coli: evidence for III^Man, III^Fru, III^Glucitol, and the phosphorylation of enzyme II^Mannitol and enzyme II^{N-acetylglucosamine}. J. Cell. Biochem. 25:139–159.

893. Weiner, J. H. 1974. The localization of glycerol-3-phosphate dehydrogenase in Escherichia coli. J. Membr. Biol. 15:1–14.

894. Weiner, J. H., and L. A. Heppel. 1972. Purification of the membrane-bound and pyridine nucleotide-independent l-glycerol 3-phosphate dehydrogenase from Escherichia coli. Biochem. Biophys. Res. Commun. 47:1360–1365.

895. Weiner, J. H., E. Lohmeier, and A. Schryvers. 1978. Cloning and expression of the glycerol-3-phosphate transport genes of Escherichia coli. Can. J. Biochem. 56:611–617.

896. West, I. C. 1970. Lactose transport coupled to proton movements in Escherichia coli. Biochem. Biophys. Res. Commun. 41:655–661.

897. West, I. C., and P. Mitchell. 1973. Stoichiometry of lactose-H⁺ symport across the plasma membrane of Escherichia coli. Biochem. J. 132:587–592.

898. White, R. J. 1968. Control of amino sugar metabolism in Escherichia coli and isolation of mutants unable to degrade amino sugars. Biochem. J. 106:847–858.

899. White, R. J. 1970. The role of the phosphoenolpyruvate phosphotransferase system in the transport of N-acetyl-d-glucosamine by Escherichia coli. Biochem. J. 118:89–92.

900. White, R. J., and P. W. Kent. 1970. An examination of the inhibitory effects of N-iodoacetylglucosamine on Escherichia coli and isolation of resistant mutants. Biochem. J. 118:81–87.

901. White, R. J., and C. A. Pasternak. 1967. The purification and properties of N-acetylglucosamine-6-phosphate deacetylase from Escherichia coli. Biochem. J. 105:121–125.

902. Wiesmeyer, H., and M. Cohn. 1960. The characterization of the pathway of maltose utilization by Escherichia coli. I. Purification and physical chemical properties of the enzyme amylomaltase. Biochim. Biophys. Acta 39:417–426.

903. Wiesmeyer, H., and M. Cohn. 1960. The characterization of the pathway of maltose utilization by Escherichia coli. II. General properties and mechanism of action of amylomaltase. Biochim. Biophys. Acta 39:427–439.

904. Wiesmeyer, H., and M. Cohn. 1960. The characterization of the pathway of maltose utilization by Escherichia coli. III. A description of the concentrating mechanism. Biochim. Biophys. Acta 39:440–447.

905. Willis, D. K., B. E. Uhlin, K. S. Amini, and A. J. Clark. 1981. Physical mapping of the srl recA: analysis of Tn10 generated insertions and deletions. Mol. Gen. Genet. 183:497–504.

906. Willis, D. K., and C. E. Furlong. 1974. Purification and properties of a ribose-binding protein from Escherichia coli. J. Biol. Chem. 249:6926–6929.

907. Willis, R. C., R. G. Morris, C. Cirakoglu, G. D. Schellenberg, N. H. Gerber, and C. E. Furlong. 1974. Preparation of the periplasmic binding proteins from Salmonella typhimurium and Escherichia coli. Arch. Biochem. Biophys. 161:64–75.

908. Wilson, D. B. 1974. The regulation and properties of the galactose transport system in Escherichia coli K12. J. Biol. Chem. 249:553–558.

909. Wilson, D. B. 1976. Properties of the entry and exit reactions of the beta-methyl galactoside transport system in Escherichia coli. J. Bacteriol. 126:1156–1165.

910. Wilson, D. B., and D. S. Hogness. 1964. The enzymes of the galactose operon in Escherichia coli. I. Purification and characterization of uridine diphosphogalactose 4-epimerase. J. Biol. Chem. 239:2469–2481.

911. Wilson, D. M., and S. Ajl. 1957. Metabolism of l-rhamnose by Escherichia coli. I. l-Rhamnose isomerase. J. Bacteriol. 73:410–414.

912. Wilson, D. M., and S. Ajl. 1957. Metabolism of l-rhamnose by Escherichia coli. II. The phosphorylation of l-rhamnulose. J. Bacteriol. 73:415–420.

913. Wilson, D. M., M. Kusch, J. L. Flagg-Newton, and T. H. Wilson. 1980. Control of lactose transport in Escherichia coli. FEBS Lett. 117:37–44.

914. Wilson, D. M., R. M. Putzrath, and T. H. Wilson. 1981. Inhibition of growth of Escherichia coli by lactose and other galactosides. Biochim. Biophys. Acta 649:377–384.

915. Wilson, T. H., and E. R. Kashket. 1969. Isolation and properties of thiogalactoside transacetylase-negative mutants of Escherichia coli. Biochim. Biophys. Acta 173:501–508.

916. Wilson, T. H., and M. Kusch. 1972. A mutant of Escherichia coli K 12 energy-uncoupled for lactose transport. Biochim. Biophys. Acta 255:786–797.

917. Wilson, T. H., M. Kusch, and E. R. Kashket. 1970. A mutant in Escherichia coli energy-uncoupled for lactose transport: a defect in the lactose-operon. Biochem. Biophys. Res. Commun. 40:1409–1414.

918. Wilson, T. H., and E. C. C. Lin. 1980. Evolution of membrane bioenergetics. J. Supramol. Struct. 13:421–446.

919. Wilson, T. H., and P. C. Mahoney. 1976. Speculations on the evolution of ion transport mechanisms. Fed. Proc. 35:2174–2179.

920. Wilson, T. H., K. Ottina, and D. M. Wilson. 1982. Melibiose transport in bacteria, p. 33–39. In A. Martonosi (ed.), Membranes and Transport, vol. 2. Plenum Publishing Corp., New York.

921. Wilson, T. H., and D. M. Wilson. 1983. Sugar-cation cotransport systems in bacteria, p. 1–39. In E. Elson, W. Frazier, and L. Glaser (ed.), Cell Membranes: Methods and Reviews, vol. 1. Plenum Publishing Corp., New York.

922. Wiman, M., G. Bortani, B. Kelly, and I. Sasaki. 1970. Genetic map of Escherichia coli C. Mol. Gen. Genet. 107:1–31.

923. Winkler, H. H. 1966. A hexose-phosphate transport system in Escherichia coli. Biochim. Biophys. Acta 117:231–240.

924. Winkler, H. H. 1970. Compartmentation in the induction of the hexose-6-phosphate transport system of Escherichia coli. J. Bacteriol. 101:470–475.

925. Winkler, H. H. 1971. Kinetics of exogenous induction of the hexose-6-phosphate transport system of Escherichia coli. J. Bacteriol. 107:74–78.

926. Winkler, H. H. 1973. Energy coupling of the hexose phosphate transport system in Escherichia coli. J. Bacteriol. 116:203–209.

927. Wohlhieter, J. A., J. R. Lazere, N. J. Snellings, E. M. Johnson, R. M. Synenki, and L. S. Baron. 1975. Characterization of transmissible genetic elements from sucrose-fermenting Salmonella typhimurium. J. Bacteriol. 122:401–406.

928. Wolfe, J. B., B. B. Britton, and H. I. Nakada. 1957. Glucosamine degradation by Escherichia coli. III. Isolation and studies of "phosphoglucosaminisomerase-aminisomerase." Arch. Biochem. Biophys. 66:333–339.

929. Wolfe, J. B., R. Y. Morita, and H. I. Nakada. 1956. Glucosamine degradation by Escherichia coli. Observations with lasting cells and dry-cell preparations. Arch. Biochem. Biophys. 63:480–488.

930. Wolfe, J. B., and H. I. Nakada. 1956. Glucosamine degradation by Escherichia coli. II. The isomeric conversion of glucosamine 6-PO₄ to fructose 6-PO₄. Arch. Biochem. J. 71:557–564.

931. Wolff, J. B., and N. O. Kaplan. 1956. Hexitol metabolism in Escherichia coli. J. Bacteriol. 71:557–564.

932. Wolff, J. B., and N. O. Kaplan. 1956. d-Mannitol 1-phosphate dehydrogenase from Escherichia coli. J. Biol. Chem. 218:849–869.

933. Wong, P. T. S., E. R. Kashket, and T. H. Wilson. 1970. Energy coupling in the lactose transport system of Escherichia coli. Proc. Natl. Acad. Sci. USA 65:63–69.

934. Woodward, M. J., and H. P. Charles. 1982. Genes for l-sorbose utilization in Escherichia coli. J. Gen. Microbiol. 128:1969–1980.

935. Woodward, M. J., and H. P. Charles. 1963. Polymorphism in Escherichia coli: rtl, atl and gat regions behave as chromosomal alternatives. J. Gen. Microbiol. 129:75–84.

936. Wovcha, M. G., D. L. Steuerwald, and K. E. Brooks. 1983. Amplification of d-xylose and d-glucose isomerase activities in Escherichia coli by gene cloning. Appl. Environ. Microbiol. 45:1402–1404.

937. Wu, H. C., and T. C. Wu. 1971. Isolation and characterization of a glucosamine-requiring mutant of Escherichia coli K-12 defective in glucosamine-6-phosphate synthetase. J. Bacteriol. 105:455–466.

938. Wu, H. C. P. 1966. Endogenous inductin of the galactose operon and the galactose transport system in Escherichia coli K-12. Proc.Natl. Acad. Sci. USA 55:622–629.

939. Wu, H. C. P. 1967. Role of the galactose transport system in the establishment of endogenous induction of the galactose operon in E. coli. J. Mol. Biol. 24:213–223.

940. Wu, H. C. P., and H. M. Kalckar. 1966. Endogenous induction of the galactose operon in Escherichia coli K12. Proc. Natl. Acad. Sci. USA 55:622–629.

941. Wu, H. C. P., and H. M. Kalckar. 1969. Role of the galactose transport system in the retention of intracellular galactose in Escherichia coli. J. Mol. Biol. 41:109–120.

942. Wu, T.-T. 1976. Growth of a mutant of Escherichia coli K-12 on xylitol by recruiting enzymes for d-xylose and l-1,2-propanediol metabolism. Biochim. Biophys. Acta 428:656–663.

943. Wu, T.-T. 1976. Growth on d-arabitol of a mutant strain of Escherichia coli K12 using a novel dehydrogenase and enzymes related to l-1,2-propanediol and d-xylose metabolism. J. Gen. Microbiol. 94:246–256.

944. Wu, T.-T., E. C. C. Lin, and S. Tanaka. 1968. Mutants of Aerobacter aerogenes capable of utilizing xylitol as a novel carbon source. J. Bacteriol. 96:447–456.

945. Yarmolinsky, M. B., H. Wiesmeyer, H. M. Kalckar, and E. Jordan. 1959. Hereditary defects in galactose metabolism in Escherichia coli mutants. II. Galactose-induced sensitivity. Proc. Natl. Acad. Sci. USA 45:1785–1791.

946. Yashphe, J., and N. O. Kaplan. 1975. Revertants of Escherichia coli mutants defective in the cyclic AMP system. Arch. Biochem. Biophys. 167:388–392.

947. Yazyu, H., S. Shiota-Niiya, T. Shimamoto, H. Kanazawa, M. Futal, and T. Tsuchiya. 1984. Nucleotide sequence of the melB gene and characteristics of deduced amino acid sequence of the melibiose carrier in Escherichia coli. J. Biol. Chem. 259:4320–4326.

948. Zabin, I. 1963. Crystalline thiogalactoside transacetylase. J. Biol. Chem. 238:3300–3306.

949. Zabin, I., and A. V. Fowler. 1978. Beta-galactosidase, the lactose permease protein, and thiogalactoside transacetylase, p. 89–121. In J. H Miller and W. S. Reznikoff (ed.), The Operon. Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.

950. Zabin, I., A. Kepes, and J. Monod. 1959. On the enzymic acetylation of isopropyl beta-d-thiogalactoside and its association with galactoside-permease. Biochem. Biophys. Res. Commun. 1:289–292.

951. Zabin, I., A. Kepes, and J. Monod. 1962. Thiogalactoside transacetylase. J. Biol. Chem. 237:253–257.

952. Zipser, D. 1963. A study of the urea-produced subunits of beta-galactosidase. J. Mol. Biol. 7:113–121.

953. Zlotnikov, K. M., V. V. Sukhodoletz, and G. E. Baumanis. 1969. The mapping of the genes which control the catabolism of nucleosides in Escherichia coli K-12. Genetika 5:114–119.

954. Zukin, R. S., P. G. Strange, L. R. Heavey, and D. E. Koshland, Jr. 1977. Properties of the galactose binding protein of Salmonella typhimurium and Escherichia coli. Biochemistry 16:381–386.

955. Zwaig, N., W. S. Kistler, and E. C. C. Lin. 1970. Glycerol kinase, the pacemaker for the dissimilation of glycerol in Escherichia coli. J. Bacteriol. 102:753–759.

956. Zwaig, N., and E. C. C. Lin. 1966. Feedback inhibition of glycerol kinase, a catabolic enzyme in Escherichia coli. Science 153:755–757.

957. Zwaig, N., and E. C. C. Lin. 1966. A method for isolating mutants resistant to catabolite repression. Biochem. Biophys. Res. Commun. 22:414–418.