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Macrina FL, Balbinder E. Genetic Characterization of a Stable F' lac Plasmid. J Bacteriol 2010; 112:503-12. [PMID: 16559163 PMCID: PMC251437 DOI: 10.1128/jb.112.1.503-512.1972] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A mutant F' plasmid has been isolated in a strain of Salmonella typhimurium harboring F(ts114)lac. This mutant, designated FlacS, exhibits unique genetic stability in strains of S. typhimurium and Escherichia coli. It shows no thermolability and is lost at frequencies of 20 to 100 times less than the wild-type F'lac (F42) in the same genetic backgrounds. The FlacS is also insensitive to conventional plasmid curing agents, whereas both F(ts114)lac and F42 are readily cured. The nature of the mutation(s) conferring stability to the FlacS is unclear, but plasmid linkage has been established. The high frequency of conjugal transfer of the FlacS and its behavior in recombination-deficient strains of S. typhimurium and E. coli argue against its stability being due to stable chromosomal integration. The FlacS is also capable of transferring chromosomal markers in S. typhimurium and E. coli mating systems. No major differences in chromosomal mobilization have been observed among F42, F(ts114)lac, and FlacS donors of either genus.
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Affiliation(s)
- F L Macrina
- Biological Research Laboratories, Department of Biology, Syracuse University, Syracuse, New York 13210
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Friedkin M. Thymidylate synthetase. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 38:235-92. [PMID: 4598071 DOI: 10.1002/9780470122839.ch5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Baetens M, Legrain C, Boyen A, Glansdorff N. Genes and enzymes of the acetyl cycle of arginine biosynthesis in the extreme thermophilic bacterium Thermus thermophilus HB27. MICROBIOLOGY (READING, ENGLAND) 1998; 144 ( Pt 2):479-492. [PMID: 9493385 DOI: 10.1099/00221287-144-2-479] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
An arginine biosynthetic gene cluster, argC-argJ, of the extreme thermophilic bacterium Thermus thermophilus HB27 was isolated by heterologous complementation of an Escherichia coli acetylornithinase mutant. The recombinant plasmid (pTHM1) conferred ornithine acetyltransferase activity to the E. coli host, implying that T. thermophilus uses the energetically more economic pathway for the deacetylation of acetylornithine. pTHM1 was, however, unable to complement an E. coli argA mutant and no acetylglutamate synthase activity could be detected in E. coli argA cells containing pTHM1. The T. thermophilus argJ-encoded enzyme is thus monofunctional and is unable to use acetyl-CoA to acetylate glutamate (contrary to the Bacillus stearothermophilus homologue). Alignment of several ornithine acetyltransferase amino acid sequences showed no obvious pattern that could account for this difference; however, the monofunctional enzymes proved to have shorter N-termini. Sequence analysis of the pTHM1 3.2 kb insert revealed the presence of the argC gene (encoding N-acetylglutamate-5-semialdehyde dehydrogenase) upstream of the argJ gene. Alignment of several N-acetylglutamate-5-semialdehyde dehydrogenase amino acid sequences allowed identification of two strongly conserved putative motifs for cofactor binding: a putative FAD-binding site and a motif reminiscent of the NADPH-binding fingerprint. The relationship between the amino acid content of both enzymes and thermostability is discussed and an effect of the GC content bias is indicated. Transcription of both the argC and argJ genes appeared to be vector-dependent. The argJ-encoded enzyme activity was twofold repressed by arginine in the native host and was inhibited by ornithine. Both upstream of the argC gene and downstream of the argJ gene an ORF with unknown function was found, indicating that the organization of the arginine biosynthetic genes in T. thermophilus is new.
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MESH Headings
- Acetyl Coenzyme A/metabolism
- Acetyltransferases/genetics
- Acetyltransferases/metabolism
- Aldehyde Oxidoreductases
- Amidohydrolases/genetics
- Amino Acid Sequence
- Amino-Acid N-Acetyltransferase
- Arginine/metabolism
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Base Composition
- Chromosome Mapping
- Cloning, Molecular
- DNA, Bacterial/analysis
- DNA, Bacterial/genetics
- Escherichia coli/genetics
- Flavin-Adenine Dinucleotide/metabolism
- Genes, Bacterial
- Genetic Complementation Test
- Glutamates/metabolism
- Molecular Sequence Data
- Multigene Family
- Mutagenesis, Insertional
- NADP/metabolism
- Open Reading Frames
- Ornithine/metabolism
- Plasmids
- Recombination, Genetic
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Thermus thermophilus/genetics
- Thermus thermophilus/metabolism
- Transcription, Genetic
- Transformation, Genetic
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Affiliation(s)
- Margot Baetens
- Vlaams Interuniversitair Instituut voor Biotechnologie, Emile Grysonlaan 1, B-1070 Brussel, Belgium
- Microbiologie, Vrije Universiteit Brussel, Emile Grysonlaan 1, B-1070 Brussel, Belgium
| | | | - Anne Boyen
- Vlaams Interuniversitair Instituut voor Biotechnologie, Emile Grysonlaan 1, B-1070 Brussel, Belgium
- Microbiologie, Vrije Universiteit Brussel, Emile Grysonlaan 1, B-1070 Brussel, Belgium
| | - Nicolas Glansdorff
- Research Institute CERIA-COOVI, Emile Grysonlaan 1, B-1070 Brussel, Belgium
- Vlaams Interuniversitair Instituut voor Biotechnologie, Emile Grysonlaan 1, B-1070 Brussel, Belgium
- Microbiologie, Vrije Universiteit Brussel, Emile Grysonlaan 1, B-1070 Brussel, Belgium
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Huan PT, Bastin DA, Whittle BL, Lindberg AA, Verma NK. Molecular characterization of the genes involved in O-antigen modification, attachment, integration and excision in Shigella flexneri bacteriophage SfV. Gene 1997; 195:217-27. [PMID: 9305767 DOI: 10.1016/s0378-1119(97)00143-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Bacteriophage SfV is a temperate phage of Shigella flexneri responsible for converting serotype Y (3,4) to serotype 5a (V; 3,4) through its glucosyl transferase gene. The glucosyl transferase (gtr) gene of SfV has been cloned and shown to partially convert S. flexneri serotype Y to serotype 5a. In this study, we found that the serotype-converting region of SfV was approximately 2.5 kb in length containing three continuous ORFs. The recombinant strain carrying the three complete ORFs expressed the type V and group antigen 3,4, both indistinguishable from that of S. flexneri 5a wild-type strain. The interruption of orf5 or orf6 gave partial conversion in the S. flexneri recombinant strain indicated by the incomplete replacement of group antigen 3,4. The region adjacent to the serotype-conversion genes was found to be identical to the attP-int-xis region of phage P22. Altogether, an approximately 2.2-kb sequence covering a portion of the serotype-conversion (approximately 500 nt)-attP-int-xis regions of SfV was remarkably similar to that of P22.
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Affiliation(s)
- P T Huan
- Division of Biochemistry and Molecular Biology, School of Life Sciences, The Australian National University, Canberra
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Kadam SK, Rehemtulla A, Sanderson KE. Cloning of rfaG, B, I, and J genes for glycosyltransferase enzymes for synthesis of the lipopolysaccharide core of Salmonella typhimurium. J Bacteriol 1985; 161:277-84. [PMID: 3155716 PMCID: PMC214868 DOI: 10.1128/jb.161.1.277-284.1985] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
R-prime plasmids carrying the pyrE-rfa-cysE region of the chromosome of Salmonella typhimurium were isolated by using the vector pULB113 (RP4::mini-Mu). One of the R-prime plasmids was used as a source of DNA to clone the rfa genes for lipopolysaccharide synthesis to pBR322. The following three hybrid plasmids were constructed: pKZ15, with a 4.0-kilobase EcoRI fragment of S. typhimurium DNA, containing the rfaG gene; pKZ27, a 9-kilobase BglII fragment with the rfaG, rfaB, and rfaI genes; and pKZ26, a 7.7-kilobase HindIII fragment with the rfaG, rfaB, rfaI, and rfaJ genes. We propose that these cloned genes code for four glycosyltransferases used for synthesis of the lipopolysaccharide core region (rfaG for glucosyltransferase I; rfaI for galactosyltransferase I; rfaB for galactosyltransferase II; and rfaJ for glucosyltransferase II). For all four genes, mutants which lacked the appropriate enzyme activity were complemented by the plasmids to give completed core lipopolysaccharide with O (somatic) side chains; for rfaG, rfaB, and rfaI, mutants gave restored or even amplified levels of the appropriate glycosyltransferase in in vitro assays. We show that the order of genes in the region is pyrE-rfaG-(rfaB-rfaI)-rfaJ-rfaL-rfaF -cysE.
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Johnson DI, Somerville RL. Evidence that repression mechanisms can exert control over the thr, leu, and ilv operons of Escherichia coli K-12. J Bacteriol 1983; 155:49-55. [PMID: 6408066 PMCID: PMC217650 DOI: 10.1128/jb.155.1.49-55.1983] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Mutants of Escherichia coli K-12 resistant to either the threonine analog DL-alpha-amino-beta-hydroxyvaleric acid or the leucine analog 5',5',5'-trifluoro-DL-leucine were isolated. One DL-alpha-amino-beta-hydroxyvaleric acid-resistant mutant strain, designated SP572, constitutively expressed the thr and ilv operons. The mutant allele, avr-16, was localized between trpR and the thr operon at min 0. The wildtype allele of avr-16, designated ileR, is trans dominant. One 5',5',5'-trifluoro-DL-leucine-resistant mutant strain, designated FLR9, expressed the leu and ilv operons constitutively. The mutant allele, flr-9, is linked to entA at min 13. The constitutive expression of the thr, leu, and ilv operons in mutants avr-16 and flr-9 was partly reversed in cells harboring a plasmid, which leads to elevated levels of the trpR gene product, the Trp aporepressor protein. Operator-like sequences situated upstream from the transcription startpoints of the thr, leu, and ilv operons are plausible candidates for targets of systems of repressor-operator control functioning in parallel with attenuation.
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The genetic analysis of Rhizobium in relation to symbiotic nitrogen fixation. Heredity (Edinb) 1980. [DOI: 10.1038/hdy.1980.59] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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9
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Cloning of genes for bacterial glycosyltransferases. I. Selection of hybrid plasmids carrying genes for two glucosyltransferases. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(17)37876-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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11
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Kato J, Kisumi M, Takagi T, Chibata I. Increase in arginine and citrulline production by 6-azauracil-resistant mutants of Bacillus subtilis. Appl Environ Microbiol 1977; 34:689-94. [PMID: 202194 PMCID: PMC242731 DOI: 10.1128/aem.34.6.689-694.1977] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In the arginine producer AHr-5, an L-arginine hydroxamate-resistant mutant of Bacillus subtilis, accumulation of N8-acetyl-L-ornithine increased as the level of L-arginine accumulation increased in the medium containing L-glutamic acid. Ornithine carbamoyltransferase of this strain was genetically derepressed. These results suggested that carbamoylphosphate might be deficient in vivo. With the intention to increase endogenous carbamoylphosphate, pyrimidine analogs inhibiting growth were selected and the mutants resistant to these compounds were derived from the AHr-5 mutant. Of the resistant mutants derived, the 6-azauracil-resistant mutant AAr-9 produced 28 mg of L-arginine per ml, which corresponded to more than twofold the amount produced by the parent strain. Derivation of an arginine-requiring mutant from the double-resistant mutant AAr-9 provides a new advantageous method for the production of L-citrulline. The increase in arginine and citrulline production is discussed.
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Fluri R, Coddington A, Flury U. The product of the ade1: gene in Schizosaccharomyces pombe: a bifunctional enzyme catalysing two distinct steps in purine biosynthesis. MOLECULAR & GENERAL GENETICS : MGG 1976; 147:271-82. [PMID: 967158 DOI: 10.1007/bf00582878] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The assignment of the known ade genes to steps in purine biosynthesis in Schizosaccharomyces pombe has been completed with the demonstration that an ade3 mutants lacks FGAR amidotransferase, ade1A mutants lack GAR synthetase and ade1B mutants lack AIR synthetase. A comparison of enzyme activity with map position for ade1 mutants shows that (1) complementing ade1A mutants lack GAR synthetase but posses wild type amounts of AIR synthetase, (2) complementing ade1B mutants lack AIR synthetase but posses variable amounts of GAR synthetase, (3) non-complementing mutants lack both activities. In wild type strains the two activities fractionate together throughout a hundred-fold purification. Hence the ade1 gene appears to code for a bifunctional enzyme catalysing two distinct steps in purine biosynthesis. The two activities are catalysed by two different regions of the polypeptide chain which can be altered independently by mutation. Gel filtration studies on partially purified enzymes from wild type and various complementing mutant strains, indicate that the bifunctional enzyme is a multimer consisting of between four and six sub-units of 40,000 daltons each. GAR synthetase activity is associated with both the monomeric and multimeric forms but AIR synthetase is only associated with the multimer. A comparison of enzyme levels between diploids and their original complementing haploid strains suggests that complementation is due to hybrid enzyme formation.
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Abstract
Cells of Azotobacter vinelandii (ATCC 12837) can be transformed by exogenous deoxyribonucleic acid towards the end of exponential growth. Transformation occurs at very low frequencies when the deoxyribonucleic acid is purified or when the transformation is carried out in liquid medium. Optimal transformation occurs on plates of Burk nitrogen-free glucose medium containing either high phosphate (10 mM) or low calcium (0 to 0.29 mM) content. Higher levels of calcium are inhibitory, whereas magnesium ions are essential for transformation and growth. Extracellular polymer and capsule are increasingly inhibitory to transformation and are most abundant when the calcium content of the medium is high. Transformation is optimal at pH 7.0 to 7.1 and at 30 C, conditions which also coincide with minimal extracellular polymer production. Nonencapsulated strains are excellent transformation recipients. Glycine-induced pleomorphism reduces the transformation frequency and the degree of inhibition is dependent on the phosphate concentration of the medium. Rifampin resistance and shifts from adenine, hypoxanthine, uracil, and nitrogenase auxotrophy to prototrophy can be achieved. Although single marker transfer is always greater than double marker transfer, the data suggest that rifampin resistance is linked to hypoxanthine, adenine and uracil protorophy at intervals of increasing distance. Rifampin resistance did not appear to be linked to nitrogenase.
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Parsons S, Koshland D. A Rapid Isolation of Phosphoribosyladenosine Triphosphate Synthetase and Comparison to Native Enzyme. J Biol Chem 1974. [DOI: 10.1016/s0021-9258(19)42489-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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15
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Friedberg D, Mikulka TW, Jones J, Calvo JM. flrB, a regulatory locus controlling branched-chain amino acid biosynthesis in Salmonella typhimurium. J Bacteriol 1974; 118:942-51. [PMID: 4598011 PMCID: PMC246843 DOI: 10.1128/jb.118.3.942-951.1974] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Salmonella typhimurium strain CV123 (ara-9 gal-205 flrB1), isolated as a mutant resistant to trifluoroleucine, has derepressed and constitutive levels of enzymes forming branched-chain amino acids. This strain grows more slowly than the parent at several temperatures, both in minimal medium and nutrient broth. It overproduces and excretes sizeable amounts of leucine, valine, and isoleucine in comparison with the parental strain. Both leuS (coding for leucyl-transfer ribonucleic acid [tRNA]synthetase) and flrB are linked to lip (min 20 to 25) by P1 transduction, whereas only leuS is linked to lip by P22 transduction. Strain CV123 containing an F' lip(+) episome from Escherichia coli has repressed levels of leucine-forming enzymes, indicating that flrB(+) is dominant to flrB. Leucyl-tRNA synthetase from strain CV123 appears to be identical to the leucyl-tRNA synthetase in the parent. No differences were detected between strain CV123 and the parent with respect to tRNA acceptor activity for a number of amino acids. Furthermore, there was no large difference between the two strains in the patterns of leucine tRNA isoaccepting species after fractionation on several different columns. Several other flrB strains exhibited temperature-sensitive excretion of leucine, i.e., they excreted leucine at 37 C but not 25 C. In one such strain, excretion at 37 C was correlated with derepression of some enzymes specified by ilv and leu. These latter results suggest that flrB codes for a protein.
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Schafer MP, Hannon WH, Levin AP. In vivo and in vitro complementation between guaB and in vivo complementation between guaA auxotrophs of Salmonella typhimurium. J Bacteriol 1974; 117:1270-9. [PMID: 4591951 PMCID: PMC246610 DOI: 10.1128/jb.117.3.1270-1279.1974] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
guaA and guaB mutants of Salmonella typhimurium were isolated utilizing the mutagen, nitrous acid. The guaB mutants were defective for inosine 5'-monophosphate (IMP) dehydrogenase activity and those mutants classified as guaA exhibited no xanthosine 5'-monophosphate aminase activity. In vivo complementation maps were determined for the mutants. The guaB map indicated that at least three complementation regions existed whereas five complementation regions were observed for the guaA mutants. The demonstration of in vitro complementation was also achieved for the guaB mutants by utilizing a process of denaturation and renaturation. All of the guaB mutants that exhibited in vivo complementation were found to exhibit in vitro complementation. No correlation was found between the degree of in vivo complementation exhibited by the various pairs of mutants and the specific enzyme activities of the same mutant pair that yielded in vitro complementation. The kinetic parameters for three of the most active guaB "complemented" enzymes and a renatured wild-type IMP dehydrogenase were then examined. No apparent differences were found in the K(m) values between any of the enzymes for substrate, IMP, activator ion, K(+), and coenzyme, oxidized nicotinamide adenine dinucleotide. Some differences were noted in the apparent V(max) values; the best "complemented" enzyme yielded only 20% of the velocity exhibited by renatured wild-type enzyme.
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Slayman CW. The Genetic Control of Membrane Transport. CURRENT TOPICS IN MEMBRANES AND TRANSPORT VOLUME 4 1974. [DOI: 10.1016/s0070-2161(08)60847-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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Pascal MC, Casse F, Chippaux M, Lepelletier M. Genetic analysis of mutants of Salmonella typhimurium deficient in formate dehydrogenase activity. MOLECULAR & GENERAL GENETICS : MGG 1973; 120:337-40. [PMID: 4568841 DOI: 10.1007/bf00268147] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Jones-Mortimer MC. Mapping of structural genes for the enzymes of cysteine biosynthesis in Escherichia coli K12 and Salmonella typhimurium LT2. Heredity (Edinb) 1973; 31:213-21. [PMID: 4590687 DOI: 10.1038/hdy.1973.76] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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20
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Gollub EG, Liu KP, Sprinson DB. Regulatory gene of phenylalanine biosynthesis (pheR) in Salmonella typhimurium. J Bacteriol 1973; 115:121-8. [PMID: 4577738 PMCID: PMC246221 DOI: 10.1128/jb.115.1.121-128.1973] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
4-Fluorophenylalanine-resistant mutants of Salmonella typhimurium were isolated in which synthesis of chorismate mutase P-prephenate dehydratase (specified by pheA) was highly elevated. Transduction analysis showed that the mutation affecting pheA activity was not linked to pheA, and conjugation and merodiploid analysis indicated that it was in the 95- to 100-min region of the Salmonella chromosome. Evidence is presented for the hypothesis that the mutation responsible for constitutivity of chorismate mutase P-prephenate dehydratase occurred in pheR, a gene specifying a cytoplasmic product that affected pheA. pheR mutants were found to carry a second mutation, tyrO. The tyrO mutation acts cis to cause increased levels of the tyrosine biosynthetic enzymes 3-deoxy-d-arabinoheptulosonate 7-phosphate synthetase (tyr) and prephenate dehydrogenase, but it has no effect on regulation of pheA.
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Abstract
Transducing frequencies of phage P22 lysates prepared from Salmonella typhimurium exponential cultures in minimal and nutrient broth media were compared. The assumption is that cells grown in a minimal medium will have one replication fork per replication unit, but cells in nutrient broth will have multiple replication forks; therefore, the frequency of genetic markers near the origin of replication will be higher in the nutrient broth culture. Analysis of transduction showed a gradient of marker frequencies from the highest (the cysG-ilv region) to the lowest (purE-trpB region) in both clockwise and counter clockwise directions. This supports our previous observation that chromosome replication proceeds bidirectionally from the origin between cysG (109 min on S. typhimurium map) and ilv (122 min) to a terminus in purE-trpB region (20 to 53 min). Since this method avoids possible artifacts of other methods, the results are assumed to reflect the sequence of chromosome replication in exponentially growing cells. Evidence for the existence of multiple replication forks in nutrient broth-grown cells was supported by the following: (i) the marker frequency data fitted the assumption of multiple replication fork formation; (ii) residual deoxyribonucleic acid increase after inhibition of protein synthesis to complete a round of chromosome synthesis which was 44% in cells grown in a minimal medium and 82% in those in nutrient broth; (iii) segregation patterns of the (3)H-thymidine-labeled chromosome strands during subsequent growth in non-radioactive medium were studied by autoradiography, and the number of replication points per chromosome per cell was estimated as 5.6 for the nutrient broth culture and 2.5 for the minimal medium culture. These data support a model of symmetrical and bidirectional chromosome replication.
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Bernstein A. The E. coli cell surface: on the genetic organization of the tolPAB cluster. MOLECULAR & GENERAL GENETICS : MGG 1973; 123:111-21. [PMID: 4579982 DOI: 10.1007/bf00267328] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Abstract
Salmonella typhimurium possesses at least three inducible transport systems for the tricarboxylic acids (citric, isocitric, cis-aconitic, and tricarballylic). The first system was induced by citrate, isocitrate, or cis-aconitate, and transported citric acid and isocitric acid. The second system was also induced by the same acids as in the first system and transported cis-aconitic acid. This system required Mg(2+) ions and was stable at pH 8.4 but unstable at pH 7.0. The metal ion was replaced with Sr(2+) or Ca(2+) ions but not with Ba(2+) ions. The third system was induced by tricarballylate and transported citric acid, cis-aconitic acid, and tricarballylic acid.
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Brenchley JE, Ingraham JL. Characterization of a cold-sensitive hisW mutant of Salmonella typhimurium. J Bacteriol 1973; 114:528-36. [PMID: 4350342 PMCID: PMC251805 DOI: 10.1128/jb.114.2.528-536.1973] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
A cold-sensitive mutant of Salmonella typhimurium LT2 that grows at 37 C but not at 20 C has altered repression regulation in at least two amino acid biosynthetic pathways (histidine and isoleucine). The lesion conferring cold sensitivity that is linked with hisW is recessive. Assays for the acceptance of some amino acids by transfer ribonucleic acid (tRNA) reveal a decreased ability of the mutant tRNA to accept arginine, phenylalanine, and histidine. A mutation in a gene for tRNA maturation is a likely possibility for the mutation producing these effects on growth, regulation, and amino acid acceptance.
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Wehr CT. Isolation and properties of a ribonuclease-deficient mutant of Salmonella typhimurium. J Bacteriol 1973; 114:96-102. [PMID: 4633352 PMCID: PMC251744 DOI: 10.1128/jb.114.1.96-102.1973] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A mutant of Salmonella typhimurium has been isolated that has less than 5% of the ribonuclease activity of the parent strain. Mutant screening and enzyme assays were done in the presence of ethylenediaminetetraacetic acid, a substance that activates ribonuclease I and inhibits other known microbial nucleases. Genetic mapping indicates that the mutation is located between the purE and gal genes on the Salmonella chromosome. A ribonuclease-deficient mutant that carries a deletion in the pyrF gene is unable to utilize ribonucleic acid as a pyrimidine source, whereas the pyrF parent with normal ribonuclease activity will grow. This suggests that the enzyme may perform a scavenge function in the utilization of exogenous ribonucleic acid. Loss of this enzyme seems to have no detrimental effects on the growth of Salmonella.
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Somers JM, Amzallag A, Middleton RB. Genetic fine structure of the leucine operon of Escherichia coli K-12. J Bacteriol 1973; 113:1268-72. [PMID: 4570778 PMCID: PMC251693 DOI: 10.1128/jb.113.3.1268-1272.1973] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The order of mutational sites in 10 independently isolated leucine auxotrophys of Escherichia coli K-12 was determined by three-point reciprocal transductions. The sites of mutation mapped in linear sequence in a cluster; all leucine auxotrophic mutations were cotransducible with mutations in the arabinose operon. The mutations were assigned to four complementation groups by abortive transduction tests, designated D, C, B, and A, reading in a clockwise direction from the arabinose operon. Enzyme analyses showed that strains with a mutation in gene A lacked alpha-isopropylmalate synthetase activity (EC 4.1.3), and those with a mutation in gene B lacked beta-isopropylmalate dehydrogenase activity (EC 1.1.1). It is concluded that the gross structure of the leucine operon in E. coli is closely similar to, if not identical with, the gross structure of the leucine operon in Salmonella typhimurium.
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27
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Slocum H, Boyer HW. Host specificity of Salmonella typhimurium deoxyribonucleic acid restriction and modification. J Bacteriol 1973; 113:724-6. [PMID: 4570605 PMCID: PMC285287 DOI: 10.1128/jb.113.2.724-726.1973] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The restriction and modification genes of Salmonella typhimurium which lie near the thr locus were transferred to a restrictionless mutant of Escherichia coli. These genes were found to be allelic to the E. coli K, B, and A restriction and modification genes. E. coli recombinants with the restriction and modification host specificity of S. typhimurium restricted phage lambda that had been modified by each of the seven known host specificities of E. coli at efficiency of plating levels of about 10(-2). Phage lambda modified with the S. typhimurium host specificity was restricted by six of the seven E. coli host specificities but not by the RII (fi(-) R-factor controlled) host specificity. It is proposed that the restriction and modification enzymes of this S. typhimurium host specificity have two substrates, one of which is a substrate for the RII host specificity enzymes.
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28
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Abstract
Of 313 motility-deficient mutants isolated from an LT2 his(amber) strain fixed in phase 1 by gene vh2(-), 25 regained motility when amber or ochre suppressors were introduced, in F' factors or by transduction. The fla mutants (23 amber, 1 ochre) fell in complementation groups A, B, C, F, K, a new group, M, and at least one further new group; the hypothesis of a fla gene which specifies only an RNA structural component of a flagellum-synthesizing basal apparatus is disproven for the corresponding genes. Hfr and transductional crosses confirmed gene assignments from complementation and indicated that flaM and another new fla locus map near H1. A small minority of motile bacteria were detectable in many of the amber fla mutants. In groups A and F some pairs of amber fla mutants complemented each other, and perhaps each of these groups corresponds to more than one structural gene. The suppressed derivatives of a mutant with an amber mutation in H1 made flagella morphologically and serologically indistinguishable from wild-type flagella. A slow-spreading but flagellate mutant showed mainly non-translational motility in broth, and in a viscous medium the bacteria reversed very frequently; its amber mutation, probably near H1, is inferred to cause a defect in chemotaxis, so that the bacteria give the avoidance reaction continuously.
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29
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Davies R, Sinskey AJ. Radiation-resistant mutants of Salmonella typhimurium LT2: development and characterization. J Bacteriol 1973; 113:133-44. [PMID: 4567137 PMCID: PMC251611 DOI: 10.1128/jb.113.1.133-144.1973] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A series of repeated exposures to gamma irradiation with intervening outgrowth of survivors was used to develop radioresistant cultures of Salmonella typhimuium LT2. Stepwise increases in resistance to both ionizing and ultraviolet irradiation were obtained independently of the presence or absence of integrated P22 prophage. Single clonal isolates, representing parent and radioresistant populations, retained the general characteristics of the LT2 parent, including serological properties, phage typing, antibiotic sensitivities, mouse virulence, and most biochemical test reactions. Resistant cells were generally larger and contained 1.8 to 2.1 times more ribonucleic acid and protein than parent cells, but deoxyribonucleic acid (DNA) contents were similar. Heterogeneity in the populations with respect to release of H(2)S, utilization of carbon sources, and growth on minimal medium is considered to be ancillary, rather than causally related, to increased radioresistance. The resistant isolates displayed an increased ability to reactivate gamma-irradiated P22 phage. DNA polymerase I and polynucleotide-joining enzyme activities were elevated in extracts of radioresistant cells relative to parent cells. It is suggested that the observed increases in radioresistance result from a selection of mutations leading to an increased capacity to repair DNA.
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30
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Blank J, Hoffee P. Regulatory mutants of the deo regulon in Salmonella typhimurium. MOLECULAR & GENERAL GENETICS : MGG 1972; 116:291-8. [PMID: 4560588 DOI: 10.1007/bf00270086] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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31
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Dendinger S, Brill WJ. Effect of the proline analogue baikiain on proline metabolism in Salmonella typhimurium. J Bacteriol 1972; 112:1134-41. [PMID: 4565530 PMCID: PMC251541 DOI: 10.1128/jb.112.3.1134-1141.1972] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A proline analogue, 4,5-dehydro-l-pipecolic acid (baikiain) induces the formation in Salmonella typhimurium of the two enzymes catalyzing the degradation of proline, proline oxidase and Delta(1)-pyrroline-5-carboxylic acid (P5C) dehydrogenase. The level of induction by 20 mm baikiain is about 10% of the maximum level induced by proline. Since the analogue is a substrate of proline oxidase the first enzyme of the proline catabolic pathway, the oxidation derivative rather than baikiain itself might be the actual effector. Baikiain is also an inducer of proline oxidase in Escherichia coli K-12 and E. coli W. An additional effect of this analogue on proline degradation in S. typhimurium is inhibition of P5C dehydrogenase. At a concentration of 5 x 10(-4)m, baikiain inhibits completely the growth of strains constitutive for proline oxidase. This inhibition, which can be overcome by proline, occurs in the presence or absence of P5C dehydrogenase activity. Three spontaneously occurring mutants resistant to baikiain were isolated from constitutive strains. All are pleiotropic-negative for the proline-degrading enzymes. The sites of these mutations are linked to the put region. Although the mechanism of toxicity has not been determined, baikiain provides a simple and direct selection for obtaining mutants unable to degrade proline. In addition, it allows selection for strains with an inducible rather than constitutive phenotype.
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32
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Rick PD, Osborn MJ. Isolation of a mutant of Salmonella typhimurium dependent on D-arabinose-5-phosphate for growth and synthesis of 3-deoxy-D-mannoctulosonate (ketodeoxyoctonate). Proc Natl Acad Sci U S A 1972; 69:3756-60. [PMID: 4566459 PMCID: PMC389865 DOI: 10.1073/pnas.69.12.3756] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A new type of auxotrophic mutant of Salmonella typhimurium has been isolated that is defective in the synthesis of the 3-deoxy-D-mannooctulosonate (ketodeoxyoctonate) region of the lipopolysaccharide and requires D-arabinose-5-phosphate for growth. Genetic and biochemical evidence indicated that the mutant defect was due to an altered ketodeoxyoctonate-8-phosphate synthetase with an apparent K(m) for D-arabinose-5-phosphate 35-fold higher than that of the parental enzyme. As a result of this enzymatic lesion, the mutant strain was dependent on exogenous D-arabinose-5-phosphate both for growth and for synthesis of a complete lipopolysaccharide.
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33
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Ahmad SI, Pritchard RH. Location of gene specifying cytosine deaminase in Escherichia coli. MOLECULAR & GENERAL GENETICS : MGG 1972; 118:323-5. [PMID: 4570159 DOI: 10.1007/bf00333567] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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34
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35
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Sanderson KE, Ross H, Ziegler L, Mäkelä PH. F + , Hfr, and F' strains of Salmonella typhimurium and Salmonella abony. BACTERIOLOGICAL REVIEWS 1972; 36:608-37. [PMID: 4568766 PMCID: PMC408334 DOI: 10.1128/br.36.4.608-637.1972] [Citation(s) in RCA: 80] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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36
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Jacoby GA. Control of the argECBH cluster in Escherichia coli. MOLECULAR & GENERAL GENETICS : MGG 1972; 117:337-48. [PMID: 4560774 DOI: 10.1007/bf00333027] [Citation(s) in RCA: 49] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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37
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Hong JS, Kaback HR. Mutants of Salmonella typhimurium and Escherichia coli pleiotropically defective in active transport. Proc Natl Acad Sci U S A 1972; 69:3336-40. [PMID: 4343963 PMCID: PMC389766 DOI: 10.1073/pnas.69.11.3336] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Two classes of mutants isolated from E. coli and Salmonella typhimurium are altered in respiration-coupled active transport, as studied in whole cells and/or isolated membrane vesicles. Mutant cells defective in D-lactate dehydrogenase (dld) transport amino acids and lactose normally. Membrane vesicles prepared from these mutants do not exhibit D-lactate-dependent transport, D-lactate oxidation, or D-lactate: dichlorophenolindophenol reductase activity. However, succinate-dependent transport is markedly enhanced in these mutants, without a corresponding increase in succinic dehydrogenase activity. The second class of mutants is defective in the coupling of electron transfer to active transport. Whole cells and membrane vesicles prepared from these etc mutants exhibit markedly reduced ability to transport amino acids, despite the ability of the vesicles to oxidize D-lactate, succinate, and NADH. Vectorial phosphorylation of alpha-methylglucoside by these mutants is normal. Electrontransfer coupling mutants are similar phenotypically to mutants uncoupled for oxidative phosphorylation (uncA), but have normal ATPase activity. Moreover, uncA mutants catalyze active transport as well as does the wild type. These experiments indicate that the ETC component is essential for the coupling of respiratory energy to active transport, and provide further evidence that the generation or utilization of ATP is not involved in these transport mechanisms.
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38
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Gemski P, Baron LS, Yamamoto N. Formation of hybrids between coliphage lambda and Salmonella phage P22 with a Salmonella typhimurium hybrid sensitive to these phages. Proc Natl Acad Sci U S A 1972; 69:3110-4. [PMID: 4564201 PMCID: PMC389715 DOI: 10.1073/pnas.69.11.3110] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
An unusual Salmonella typhimurium hybrid with sensitivity to coliphage lambda and salmonella phage P22 has been recovered from matings between an Escherichia coli K-12 Hfr donor and an S. typhimurium recipient. The hybrid is an excellent host for achieving genetic recombination between lambda and P22. Two broad classes of hybrid phages were isolated. The lambda-P22 hybrid class, which has the protein coat of lambda, contains at least the c region of P22. The P22-lambda hybrid class has the protein coat of P22 and has inherited at least the c marker of lambda.
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39
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Cordaro JC, Roseman S. Deletion mapping of the genes coding for HPr and enzyme I of the phosphoenolpyruvate: sugar phosphotransferase system in Salmonella typhimurium. J Bacteriol 1972; 112:17-29. [PMID: 4562394 PMCID: PMC251376 DOI: 10.1128/jb.112.1.17-29.1972] [Citation(s) in RCA: 97] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Sugars transported by a bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) require two soluble proteins: HPr, a low-molecular-weight phosphate-carrier protein, and enzyme I. The structural genes coding for HPr (ptsH) and Enzyme I (ptsI) are shown to be cotransducible in Salmonella typhimurium. The gene order of this region of the Salmonella chromosome is cysA-trzA-ptsH-ptsI...(crr). A method for the isolation of trzA-pts deletion is described. One class of pts deletions extends through ptsH and into ptsI; a second class includes both ptsH and ptsI and extends into or through the crr gene. The crr gene either codes for or regulates the synthesis of a third PTS protein (factor III) which is sugar-specific. A hypothesis is presented for a mechanism of deletion formation.
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40
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Sanderson KE, Saeed YA. P22-mediated transduction analysis of the rough A (rfa) region of the chromosome of Salmonella typhimurium. J Bacteriol 1972; 112:58-63. [PMID: 4562411 PMCID: PMC251380 DOI: 10.1128/jb.112.1.58-63.1972] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Seven temperature-sensitive rough mutants of Salmonella typhimurium were found to be sensitive to smooth-specific phages at low temperature (25 C, 30 C) and resistant or partially resistant to rough-specific phages, whereas at high temperatures (37 C, 45 C) they were resistant or partially resistant to smooth-specific phages but sensitive to rough-specific phages. These data indicate that at low temperature each strain makes lipopolysaccharide which is relatively normal, but at high temperatures O-specific side chains are not added to the lipopolysaccharide. At 45 C, these strains have the R-res-1 or R-res-2 phage sensitivity phenotype, and their genetic lesions map by P22-mediated transduction in the rfa gene cluster between cysE-pyrE, suggesting a mutation in genes with transferase functions. P22-mediated joint transduction with temperature-sensitive rfa mutants, leaky rfa mutants, and rfa P22 lysogens have shown the following order of genes in the S. typhimurium linkage map: xyl-mtlA-mtlB-cysE-rfaF-rfaG-pyrE. An rfaE allele was not jointly transduced in the cysE-pyrE segment.
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41
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Sanderson KE, Saeed H. Insertion of the F factor into the cluster of rfa (rough A) genes of Salmonella typhimurium. J Bacteriol 1972; 112:64-73. [PMID: 4562416 PMCID: PMC251381 DOI: 10.1128/jb.112.1.64-73.1972] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
From F(+) strains of Salmonella typhimurium, isolates were obtained representing two new classes of Hfr strains, HfrK1 and HfrK2, in which the insertion of the F factor into the rfa genes results in chromosome mobilization either clockwise or anticlockwise from rfa, and in the Rfa phenotype. The point of insertion of the F factor into the cluster of rfa genes, revealed by studies of the early transfer of their normal alleles, is as follows: xyl-cysE-rfa-657 (HfrK2-1, SA540 -->)-(<-- HfrK1-1, SA458)-rfaG-(<-- HfrK1-2, SA464)-pyrE-metA
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42
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Kuo TT, Stocker BA. Mapping of
rfa
Genes in
Salmonella typhimurium
by ES18 and P22 Transduction and by Conjugation. J Bacteriol 1972; 112:48-57. [PMID: 16559160 PMCID: PMC251379 DOI: 10.1128/jb.112.1.48-57.1972] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Loci termed
rfa
, determining biosynthesis of somatic lipopolysaccharide core, have been mapped in
Salmonella typhimurium
LT2. The smooth-specific phage P22 co-transduced two leaky
rfa
alleles with
cysE
and with
pyrE
; one of the leaky alleles is perhaps
rfaG
, and the other is an unidentified gene concerned with synthesis of the heptose-containing part of the core. The lipopolysaccharide-indifferent phage ES18 (or its variant ES18.
h1
) co-transduced
rfaF, rfaG, rfaL, rfa
(R-res-1), and
rfa
(R-res-2) alleles with
cysE
and with
pyrE
, at rates indicating the order
cysE–rfaF
–(
rfa
[R-res-1],
rfa
[
r-res-2
],
rfaL
)–
rfaG–pyrE
. One proven (and two suspected)
rfaE
alleles and five proven
rfaH
alleles were not co-transduced with
cysE
or
pyrE
. Hfr crosses indicated that the proven
rfaE
allele mapped between
serA
and
strA
.
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Affiliation(s)
- T T Kuo
- Department of Medical Microbiology, Stanford University School of Medicine, Stanford, California 94305
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43
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Cold-sensitive Mutants of Salmonella typhimurium Defective in Uridine Monophosphate Kinase (pyrH). J Biol Chem 1972. [DOI: 10.1016/s0021-9258(19)44791-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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44
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Baskerville EN, Twarog R. Regulation of the tryptophan synthetic enzymes in Clostridium butyricum. J Bacteriol 1972; 112:304-14. [PMID: 5079066 PMCID: PMC251413 DOI: 10.1128/jb.112.1.304-314.1972] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Experiments concerned with the regulation of the tryptophan synthetic enzymes in anaerobes were carried out with a strain of Clostridium butyricum. Enzyme activities for four of the five synthetic reactions were readily detected in wild-type cells grown in minimal medium. The enzymes mediating reactions 3, 4, and 5 were derepressed 4- to 20-fold, and the data suggest that these enzymes are coordinately controlled in this anaerobe. The first enzyme of the pathway, anthranilate synthetase, could be derepressed approximately 90-fold under these conditions, suggesting that this enzyme is semicoordinately controlled. Mutants resistant to 5-methyl tryptophan were isolated, and two of these were selected for further analysis. Both mutants retained high constitutive levels of the tryptophan synthetic enzymes even in the presence of repressing concentrations of tryptophan. The anthranilate synthetase from one mutant was more sensitive to feedback inhibition by tryptophan than the enzyme from wild-type cells. The enzyme from the second mutant was comparatively resistant to feedback inhibition by tryptophan. Neither strain excreted tryptophan into the culture fluid. Tryptophan inhibits anthranilate synthetase from wild-type cells noncompetitively with respect to chorismate and uncompetitively with respect to glutamine. The Michaelis constants calculated for chorismate and glutamine are 7.6 x 10(-5)m and 6.7 x 10(-5)m, respectively. The molecular weights of the enzymes estimated by zonal centrifugation in sucrose and by gel filtration ranged from 24,000 to 89,000. With the possible exception of a tryptophan synthetase complex, there was no evidence for the existence of other enzyme aggregates. The data indicate that tryptophan synthesis is regulated by repression control of the relevant enzymes and by feedback inhibition of anthranilate synthetase. That this enzyme system more closely resembles that found in Bacillus than that found in enteric bacteria is discussed.
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45
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Beck CF, Ingraham JL, Neuhard J. Location on the chromosome of Salmonella typhimurium of genes governing pyrimidine metabolism. II. Uridine kinase, cytosine deaminase and thymidine kinase. MOLECULAR & GENERAL GENETICS : MGG 1972; 115:208-15. [PMID: 4555675 DOI: 10.1007/bf00268884] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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46
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Jones RT, Koeltzow DE, Stocker BA. Genetic transfer of Salmonella typhimurium and Escherichia coli lipopolysaccharide antigens to Escherichia coli K-12. J Bacteriol 1972; 111:758-70. [PMID: 4559827 PMCID: PMC251350 DOI: 10.1128/jb.111.3.758-770.1972] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Escherichia coli K-12 varkappa971 was crossed with a smooth Salmonella typhimurium donor, HfrK6, which transfers early the ilv-linked rfa region determining lipopolysaccharide (LPS) core structure. Two ilv(+) hybrids differing in their response to the LPS-specific phages FO and C21 were then crossed with S. typhimurium HfrK9, which transfers early the rfb gene cluster determining O repeat unit structure. Most recombinants selected for his(+) (near rfb) were agglutinated by Salmonella factor 4 antiserum. Transfer of an F' factor (FS400) carrying the rfb-his region of S. typhimurium to the same two ilv(+) hybrids gave similar results. LPS extracted from two ilv(+),his(+), factor 4-positive hybrids contained abequose, the immunodominant sugar for factor 4 specificity. By contrast, his(+) hybrids obtained from varkappa971 itself by similar HfrK9 and F'FS400 crosses were not agglutinated by factor 4 antiserum, indicating that the parental E. coli varkappa971 does not have the capacity to attach Salmonella O repeat units to its LPS core. It is concluded that the Salmonella rfb genes are expressed only in E. coli varkappa971 hybrids which have also acquired ilv-linked genes (presumably rfa genes affecting core structure or O-translocase ability, or both) from a S. typhimurium donor. When E. coli varkappa971 was crossed with a smooth E. coli donor, Hfr59, of serotype O8, which transfers his early, most his(+) recombinants were agglutinated by E. coli O8 antiserum and lysed by the O8-specific phage, Omega8. This suggests that, although the parental E. coli K-12 strain varkappa971 cannot attach Salmonella-specific repeat units to its LPS core, it does have the capacity to attach E. coli O8-specific repeat units.
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47
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Luckey M, Pollack JR, Wayne R, Ames BN, Neilands JB. Iron uptake in Salmonella typhimurium: utilization of exogenous siderochromes as iron carriers. J Bacteriol 1972; 111:731-8. [PMID: 4559824 PMCID: PMC251346 DOI: 10.1128/jb.111.3.731-738.1972] [Citation(s) in RCA: 168] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Aerobic microorganisms have evolved a variety of siderochromes, special ligands which can dissolve insoluble ferric iron and facilitate its transport into the cell. We have found that enb mutants of Salmonella typhimurium blocked in the biosynthesis of enterobactin (its natural iron carrier) are able to utilize siderochromes of different types made by other microorganisms as iron carriers. The antibiotic albomycin delta(2) was used to select mutants defective in ferrichrome-mediated iron uptake. Twelve classes of albomycin-resistant mutants, named sid, were defined on the basis of their growth responses to other siderochromes. Most of these classes have genetic lesions in loci that are cotransduced with panC (represented at 9 min on the genetic map). The locus designated sidJ is cotransduced with enb, whereas sidK and sidL are linked with neither panC nor enb. Genetic and physiological data indicate that S. typhimurium has several transport systems of high specificity for a variety of siderochromes produced by other microorganisms.
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48
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Adelberg EA, Bergquist P. The stabilization of episomal integration by genetic inversion: a general hypothesis. Proc Natl Acad Sci U S A 1972; 69:2061-5. [PMID: 4559592 PMCID: PMC426868 DOI: 10.1073/pnas.69.8.2061] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In F' cells of Escherichia coli K12, recombination in the region of genetic duplication between chromosome and F-genote produces a rapid alteration between the integrated and detached states of the episome. Nevertheless, F' strains can give rise to Hfr cells in which the F-genote has undergone stable integration. We have found that one such Hfr has retained the genetic duplication as well as the recombination proficiency of the parental F' strain; to account for the failure of recombination to detach the episome in this Hfr, we have postulated the inversion of one of the duplicated regions. A general model is presented, showing that an inversion must prevent episome detachment by any combination of genetic crossovers.
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49
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Abstract
Tryptophan biosynthesis in Salmonella is controlled by at least one regulatory gene, trpR, which is cotransducible with thr genes and not with the trp operon. Mutations in trpR cause derepression of tryptophan enzyme synthesis and confer resistance to growth inhibition by 5-methyltryptophan. Nineteen trpR mutations were mapped with respect to thrA and serB markers by two-point (ratio) and three-point transduction tests. The results are all consistent with the site order serB80-trpR-thrA59 on the Salmonella chromosome. Very low or undetectable levels of recombination between different trpR mutations have so far prevented the determination of fine structure in the trpR gene. Thirteen other 5-methyltryptophan-resistant mutants previously found not to be cotransducible with either the trp operon or thrA, and designated trpT, were also used in these experiments. Lack of cotransducibility with thrA was confirmed, and no linkage with serB was detected. The nature and location of trpT mutations remain obscure.
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50
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Jargiello P, Hoffee P. Orientation of the deo genes and the serB locus in Salmonella typhimurium. J Bacteriol 1972; 111:296-7. [PMID: 4591483 PMCID: PMC251274 DOI: 10.1128/jb.111.1.296-297.1972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In Salmonella typhimurium, the order of the deo genes with respect to the serB locus has been determined as deoC-deoA-deoB-deoD-serB-thr.
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