J Bacteriol, 1977 Aug, 131(2), 716 - 8 Phosphoenolpyruvate:sugar phosphotransferase system in Ancalomicrobium adetum; Saier MH Jr et al.; Ancalomicrobium adetum possesses a membrane-associated phosphoenolpyruvate:sugar phosphotransferase system, the components of which exhibited enzymatic cross-reactivity with those from Salmonella typhimurium. J Bacteriol, 1977 Aug, 131(2), 583 - 8 Characterization of an endonuclease associated with the drug resistance plasmid pKM101; Lackey D et al.; An endonuclease was detected in strains of Salmonella typhimurium containing the drug resistance plasmid pKM101 . The enzyme was not detectable in strains lacking this plasmid, but it was present in strains containing mutants of pKM101 that were no longer able to enhance host cell mutagenesis . The endonuclease had a molecular weight of roughly 75,000 and, at pH 7.0, was equally active on single-stranded and duplex deoxyribonucleic acid (DNA) . The reaction with single-stranded DNA was optimal at pH 5.5, whereas with duplex DNA the optimum was pH 6.8 . The enzyme required a divalent cation for activity, and it had no detectable exonuclease activity with single-stranded or duplex DNA . The endonuclease extensively degraded DNA with no apparent base specificity, forming 5'-phosphomonoester termini . Although characterization of the endonuclease has not revealed its function, the enzyme does not appear to be a restriction endonuclease. J Biol Chem, 1977 Jul 25, 252(14), 4904 - 12 Lipid A mutants of Salmonella typhimurium . Purification and characterization of a lipid A precursor produced by a mutant in 3-deoxy-D-mannooctulosonate-8-phosphate synthetase; Rick PD et al.; We describe here the isolation, purification, and structural characterization of a lipid A precursor synthesized under nonpermissive conditions by a mutant of Salmonella typhimurium conditionally defective in the synthesis of the 3-deoxy-D-mannoctulosonate (2-keto-3-deoxyoctonate, KDO) region of the lipopolysaccharide . The precursor was isolated free from lipopolysaccharide, murein, and phospholipids by extraction of delipidated cells with 90% phenol/CHCL3/petroleum ether . The molecule was recovered from the phenol phase after precipitation of lipopolysaccharide with H2O and subsequently purified by DEAE-cellulose chromatography . Structural analyses showed that the lipid A precursor is a phosphorylated glucosamine disaccharide containing one ester and two amide-linked residues of beta-hydroxymyristate . In contrast to lipid A, the precursor disaccharide lacks ester-linked 12:0 and 14:0 fatty acids as well as KDO . The molecule contains 2 phosphate residues both of which were identified as phosphomonoesters by 31P NMR spectroscopy . One of the phosphomonoesters is located in position 1 of the reducing terminal glucosamine residue; the location of the other phosphomonoester was not determined . The structure of the precursor provides strong support for the conclusion that KDO incorporation occurs at an early stage in lipid A biosynthesis prior to the incorporation of ester-linked saturated fatty acids. Biochim Biophys Acta, 1977 Jul 21, 498(1), 282 - 93 Stereoselectivity and stereospecificity of the alpha,beta-dihydroxyacid dehydratase from Salmonella typhimurium; Armstrong FB et al.; 1 . In addition to the known 2R,3R- and 2R, 3S-2,3-dihydroxy-3-methylpentanoic acids (DHI), the 1S,3S- and sS,DR-isomers were prepared . 2S-2,3-Dihydroxy-3-methylbutanoic acid (DHV) was also prepared in addition to the known 2R-isomer . 2 . The six dihydroxy acids were examined for their ability to promote the growth of isoleucine-valine (ilv)-requiring strains of Salmonella typhimurium and to serve as substrates for the alpha,beta-dihydroxyacid dehydratase of the same organism . 3 . Only 2R,3R-2,3-dihydroxy-3-methylpentanoic and 2R-2,3-dihydroxy-3-methylbutanoic acids supported growth of the ilv strains of S . typhimurium . 4 . alpha,beta-Dihydroxyacid dehydratase utilized the three isomers with the 2R-configuration as substrates but not those with the 2S-configuration . 5 . In an additional growth study that utilized the 3R- and 3S-isomers of 3-methyl-2-oxopentanoic acid, the alpha-keto acid analogue of isoleucine, only the 3S-isomer supported growth . 6 . It is concluded that the mechanism of action of the dehydratase is stereospecific in that the proton that is attached to C-3 of the substrate occupies the same steriochemical position as the departing hydroxyl group (Fig . 6). Mutat Res, 1977 Jul, 44(1), 9 - 19 Testing of some azo dyes and their reduction products for mutagenicity using Salmonella typhimurium TA 1538; Garner RC et al.; A series of ten azo dyes as well as various single ring aromatic amines substituted on the benzene ring were tested for bacterial mutagenicity with Salmonella typhimurium TA 1538 using a soft-agar overlay method . Two dyes, sudan 2 and chrysoidin induced mutation but only in the presence of a rat liver preparation . Chrysoidin was the more active . Testing of its reduction products, aniline and 1,2,4-triaminobenzene showed a liver metabolite of the latter compound could be responsible for the mutagenic effect, having a comparable mutagenicity with 1,2-diamino-4-nitro-benzene, one of the mutagenic constituents of hair dyes . Structure-activity studies on a series of ring-substituted anilines indicated that mutagenic activity required at least two positions to be substituted with either amino or nitro groups, or one of each . The bacteria as well as the liver enzyme preparation may partake in the activation of these chemicals . The correlation between mutagenicity and carcinogenicity for this group of compounds is discussed. J Gen Microbiol, 1977 Jul, 101(1), 143 - 9 DNA degradation in wild-type and repair-deficient strains of salmonella typhimurium exposed to ultraviolet light of photodynamic treatment; Ziebell R et al.; Five mutants of Salmonella typhimurium strain LT2 trp DI (ColEI)+, initiallly detected because they released little or no colicin when tested on solid medium, proved to be sensitive to ultraviotet light (u.v.) . Further testing indicated that one of the mutants was deficient in genetic recombination and was probably a recA-type mutant, while three of the others were deficient in DNA polymerase activity and appeared to be typical polA mutants . The fifth mutant was less sensitive than the others to methyl methanesulphonate, showed reduced proficiency in genetic recombination, and was of approximately normal u.v . mutability . This mutant may be a counterpart of the class known as uvrD in Escherichia coli . All five mutants degraded significantly more of their DNA following exposure to u.v . than did the wild-type strain . The recA-type mutant and the possible uvrD mutant also degraded significantly more of their DNA spontaneously than did the wild-type . Treatment with visible light and acridine orange (photodynamic treatment) cause no significant degradation of DNA in the wild-type strain, a highly significant increase in the extent of DNA degradation in a polA mutant, and a decrease in the extent of degradation in the recA-type mutant. Cancer Lett, 1977 Jul, 3(1-2), 1 - 8 Mutagenicity of smoke condensates from cigarettes, cigars and pipe tobacco; Sato S et al.; Smoke condensates from cigarettes, cigars and pipe tobacco were mutagenic on Salmonella typhimurium TA100 and TA98 when activated with rat liver microsomal system . Mutagenicity of a unit weight of smoke condensate was rather high in cigars, low in pipe tobacco and intermediate in cigarettes . Specific mutagenic activity was almost comparable among smoke condensates from low- to high-tar cigarettes, although some variations were observed depending upon the country producing the cigarettes . Marked mutagenicity of cigarette smoke condensate could not be explained by the benzo (a) pyrene or nitroso compounds it actually contained, suggesting the presence of other very potent mutagens in tobacco smoke condensates. Infect Immun, 1977 Jul, 17(1), 98 - 104 Role of endotoxin contamination in ribiosomal vaccines prepared from Salmonella typhimurium; Misfeldt ML et al.; Ribosomal vaccines prepared from Salmonella typhimurium SR-11 and 6707 an Re mutant bacterium of strain LT2, were effective immunogens in A/J and C3H/HeDub inbred mice . Only SR-11 ribosomes were able to induce significant protection in C3H/HeJ mice . C57BL/6J mice were not protected by either ribosomal preparation . A/J mice were protected against salmonella infection by purified SR-11 endotoxin preparations . Neither the C3H/HeDub, the C3H/HeJ, nor the C57BL/6J mice were protected by the endotoxin preparation . Passive hemagglutination studies showed that C3H/HeJ mice had no antibodies to O antigen but were significantly protected by SR-11 ribosomes . In contrast, C57BL/6J mice, which had the highest titers of O antibodies of the four inbred mouse strains, were not protected by SR-11 ribosomes . Endotoxin cannot totally account for the effectiveness fo ribosomal account for the effectiveness of ribosomal vaccines prepared from S . typhimurium. Mutat Res, 1977 Jul, 48(3-4), 319 - 25 Relation between chemical constituents of tobacco and mutagenic activity of cigarette smoke condensate; Mizusaki S et al.; Mutagenic activities of cigarette smoke condensate were assayed in the presence of S-9 Mix using Salmonella typhimurium TA 98 . The results were examined in relation to chemical data of tobacco leaves . Among the nitrogenous constituents examined, the contents of total nitrogen and protein nitrogen and the soluble nitrogenous fraction were positively and significantly related to an increase in mutagenic activity of the smoke condensate, whereas nicotine and nitrate were not important in contributing to mutagenic potency of such condensates . The age of tobacco leaves influenced the mutagenic potency of the condensate, which was lowest in leaves from the lower stalk position and increased with ascending leaf position on the stalk . Smoke condensate from tobacco with higher sugar content resulted in lower mutagenic activity . The present results, together with the previous study on the mutagenicity of the amino acid pyrolyzates, suggest that potent mutagens in cigarette smoke condensate are nitrogen-containing compounds, which may be formed from proteins and amino acids during the burning of a cigarette. Mutat Res, 1977 Jul, 48(3-4), 313 - 8 Mutagenicity of nitrovin--a nitrofuran feed additive; Joner PE et al.; Nitrovin, a nitrofuran feed additive, is shown to be directly mutagenic in Salmonella typhimurium TA 98 and TA 100 between 0.1 and 2.5 microgram per plate (0.09--2.3 micrometer) . Addition of a rat-liver homogenate reduces the mutation rates . Nitrovin inhibits growth of the same bacteria in suspension cultures at concentrations above 0.09 micrometer. Mutat Res, 1977 Jul, 48(3-4), 307 - 12 Mutagenicity tests on anthelmintics: microsomal activation of viprynium embonate to a mutagen; Macphee DG et al.; Eight anthelmintic preparations readily available in Australia were tested for mutagenicity in the Salmonella typhimurium test system . A slightly modified version of the procedure recommended by Ames et al . {2} was adopted, in that the test samples were placed in "wells" cut out of the agar of a plate previously seeded with the appropriate tester strain . Addition of a mixture of rat liver microsomal enzymes and appropriate co-factors ("S-9 mix") to one of the two wells on a single plate allowed a possible requirement for metabolic activation to be recognised . Using this procedure, viprynium embonate was found to be non-mutagenic . It was however, activated by the rat liver microsome preparation to a mutagen capable of causing both base-pair substitution (detected with strain TA100) and frameshift (detected with strain TA98) mutations . The other seven compounds tested all gave negative results in this system. Mutat Res, 1977 Jul, 48(3-4), 279 - 86 Mutagenic activity of amino acid pyrolyzates in Salmonella typhimurium TA 98; Matsumoto T et al.; Pyrolyzates of 25 amino acids and 5 indole derivatives were tested for mutagenicity in the histidine-requiring mutant Salmonella typhimurium TA 98 . Significant mutagenic activity was detected with pyrolyzates of most of the amino acids . These pyrolyzates required a liver microsomal fraction, as representative of mammalian metabolism, to be detected as mutagens . Among the pyrolyzates tested, the highest mutagenic activity was observed with that of L-tryptophan . As little as 10 microgram of the pyrolyzate of L-tryptophan had detectable mutagenic activity toward TA 98 . The optimal pyrolysis temperatures for the formation of mutagenic products were shown to be 500 degrees C for L-tryptophan and 600 degrees C for the other amino acids . The results from pyrolyses of some indole derivatives suggest that an amino group at the alpha-position to the carboxyl group of L-tryptophan plays an important role in the formation of mutagens. Mutat Res, 1977 Jul, 48(3-4), 271 - 8 Mutagenic studies with acrylonitrile; Milvy P et al.; The mutagenicity of acrylonitrile (vinyl cyanide, propenenitrile) has been demonstrated in the Ames Salmonella typhimurium/liver microsome assay system . Acrylonitrile, in the presence of a mouse liver homogenate produced mutations in the TA 1535, TA 1538 and TA 1978 strains . Exposure of the bacteria was achieved by spotting the acrylonitrile on a "lawn" of salmonella, by shaking a reaction mixture consisting of bacteria, liver homogenate and acrylonitrile, and by exposing the homogenate and bacteria to an atmosphere containing the acrylonitrile . Mutagenesis by this latter method was observed at exposures as low as 57 ppm, less than three times the TLV of 20 ppm that is designated in the United States. J Bacteriol, 1977 Jul, 131(1), 111 - 8 Regulation of L-cystine transport in Salmonella typhimurium; Baptist EW et al.; A kinetic analysis of L-cystine uptake in wild-type Salmonella typhimurium indicates the presence of at least two, and possibly three, separate transport systems . CTS-1 accounts for the majority of uptake at 20 muM L-cystine, with a Vmax of 9.5 nmol/min per mg and a Km of 2.0 muM; CTS-2 is a low-capacity, higher-affinity system with a Vmax of 0.22 nmol/min per mg and a Km of 0.05 muM; a third, nonsaturable process has been designated CTS-3 . We find that wild-type CTS-1 levels are at least 11 times higher in sulfur-limited cells than in L-cystine-grown cells . Pleiotropic cysteine auxotrophs of the types cysE (lacking serine transacetylase) and cysB- (lacking a regulatory element of positive control) have very low levels of CTS-1 even when grown under conditions of sulfur limitation, which response is analogous to that previously observed for cysteine biosynthetic enzymes (N . M . Kredich, J . Biol . Chem . 246:3474-3484, 1971) . CTS-1 is induced in cysE mutants by growth in the presence of O-acetyl-L-serine (the product of serine transacetylase), again paralleling the behavior of the cysteine biosynthetic pathway . Strain DW25, a prototrophic cysBc mutant, which is constitutive for cysteine biosynthesis, is also derepressed for CTS-1 when grown on L-cystine . Since CTS-1 is regulated by sulfur limitation, O-acetyl-L-serine, and the cysB gene product, the same three conditions controlling cysteine biosynthesis, we propose that this transport system is a part of the cysteine regulon. Cancer Lett, 1977 Jul, 3(1-2), 45 - 52 Correlation of bacterial mutagenicity and hamster cell transformation with tumorigenicity induced by 2,4-toluenediamine; Pienta RJ et al.; In the presence of rat liver microsome enzymes, 2,4-toluenediamine (TDA) was mutagenic for several tester strains of Salmonella typhimurium . TDA induced morphological transformation in an in vitro carcinogenesis system using secondary culture target cells prepared from cryopreserved primary Syrian hamster embryo cells . These results now correlate bacterial mutagenicity and in vitro morphological transformation with the reported tumorigenicity of this compound. Cancer Res, 1977 Jul, 37(7 Pt 1), 2209 - 13 Mutagenicity of cancer chemotherapeutic agents in the Salmonella/microsome test; Benedict WF et al.; Seventeen cancer chemotherapeutic agents were tested for their ability to mutate Salmonella typhimurium tester strains in the Salmonella/microsome mutagenicity test . There was a high correlation between the mutagenicity and carcinogenicity of a given agent . Carcinogens positive in the test were Adriamycin, daunomycin, 1-propanol-3,3'-iminodimethanesulfonate, cyclophosphamide, isophosphamide, hycanthone, chlornaphazin, nitrogen mustard, uracil mustard, melphalan, and thio-tepa . Two carcinogesn, actinomycin D and bleomycin, were not detected as mutagens . The presumptive noncarcinogen, methotrexate, was negative in the test . Tilorone and 6-mercaptopurine, tentatively classified as noncarcinogens, were mutagenic . The carcinogenicity of cis-dichlorodiammineplatinum(II), which was positive in the test, has not been determined. Genetics, 1977 Jul, 86(3), 513 - 26 Characterization of Salmonella typhimurium mutants with altered glutamine synthetase activity; Funanage VL et al.; A number of glutamine auxotrophs of Salmonella typhimurium were isolated and characterized genetically . Three of the mutations appear to be closely linked and are complemented by episomes carrying the glnA region of Escherichia coli . The lesions in these strains are approximately 20% linked by P1 transduction with a mutation in the rha gene, but are unlinked to ilv . Another mutation causing glutamine auxotrophy in strain JB674 is genetically distinct from the others . Strain JB674 grown in glucose medium containing ammonia as the nitrogen source has reduced levels of glutamine synthetase that is more adenylylated than in the parent strain, suggesting that the enzyme can not be deadenylylated normally . The lesion causing glutamine auxotrophy in JB674 lies in the region corresponding to the glnB and glnE genes affecting glutamine synthetase modification in Klebsiella areogenes . Four Gln+ revertants of JB674 have glutamine synthetase activities 4 to 6 fold higher than normal . One mutation causing this increased enzyme synthesis has been shown by three-factor crosses with the glnA mutations to lie near or within the glnA gene. J Biol Chem, 1977 Jun 25, 252(12), 4416 - 7 Phosphoprotein phosphatase activity associated with the cytoplasmic membrane of Salmonella typhimurium and Escherichia coli; Tuttle RC et al.; Membrane-associated phosphoprotein phosphatase activity was demonstrated in extracts of Salmonella typhimurium and Escherichia coli . The active protein could be extracted from the membrane as a large water-soluble complex (Mr greater than 150,000) . Maximal activity was observed at pH 6 to 7 in the presence of a divalent cation . The enzyme appears to be distinct from previously described phosphatases. Mol Gen Genet, 1977 Jun 8, 153(2), 205 - 10 Effect of mutant host RNA polymerase on the bifunctional activities of P22 gene c1; Tokuno S et al.; The product of phage P22 gene c1 has two functions: (1) it promotes synthesis of repressor and (2) during the first minutes of infection it retards expression of some lytic genes . We call the second, negative function "c1 retardation" . We investigated c1 retardation in a mutant host of Salmonella typhimurium that is resistant to rifampicin and carries an altered RNA polymerase . No c1 retardation of DNA synthesis was detectable in this host after infection with wild-type phages . This elimination of the normally detectable c1 function leads to the conclusion that the mutant RNA polymerase interferes with the expression of c1 gene activity . Wild-type genes form clear plaques on the mutant host . Mutants of P22 called cly were isolated by others . These mutants form turbid plaques on the altered RNA polymerase host . Infections with P22 cly in the mutant host resulted in detectable c1 retardation . The cly mutation therefore restores c1 activity in a host which wild-type c1 is not expressed . Two spontaneous mutants were isolated from the mutant host . These two strains allowed partial expression of c1 retardation, although they remained rifampicin resistant . We interpret our data to indicate that expression of the normal functions of the gene c1 product requires an interaction of that product with the host RNA polymerase. Mol Gen Genet, 1977 Jun 8, 153(2), 179 - 83 On the ability of Salmonella typhimurium cells to form deoxycytidine nucleotides; Janion C; It is known that cdd- S . typhimurium mutants selected for resistance to 5-fluorodeoxycytidine (FdCyd) possess no deoxycytidine kinase activity . The present study postulates that this method of screening selects double mutants defective in cytidine deaminase and in deoxycytidine kinase . To prove this hypothesis, the cdd mutant of S . typhimurium was constructed by P1-mediated transfer of ccd- gene into a new genetic background, and the activity of deoxycytidine kinase was assayed . Transductants exhibited no deoxycytidine kinase activity, showing that the absence of this enzyme is not limited to a specific cdd- mutant, but includes all strains of S . typhimurium . The toxicity of FdCyd for the bacterial strains possessing deoxycytidine kinase, as well as the role of nucleoside phosphorylase in nucleotide formation by S . typhimurium, is discussed. Nucleic Acids Res, 1977 Jun, 4(6), 1945 - 56 Biosynthesis of tRNA in histidine regulatory mutants of Salmonella typhimurium; Bossi L et al.; HisU mutants of Salmonella typhimurium are depressed in the histidine operon since they have lower intracellular concentration of histidyl-tRNAHis . In this paper we present evidences showing that a strain carrying a hisU mutation (hisUl206) is altered in a nucleolytic enzyme involved in tRNA maturation process . The analysis of several hisU mutants indicates that hisU region of bacterial genome may account for more than one function involved in tRNA biosynthesis. Acta Pathol Microbiol Scand {B}, 1977 Jun, 85(3), 212 - 8 The tendency of smooth and rough Salmonella typhimurium bacteria and lipopolysaccharide to hydrophobic and ionic interaction, as studied in aqueous polymer two-phase systems; Magnusson KE et al.; In aqueous two-phase system, the partition of bacteria and lipopolysaccharide from a rough (R) strain (Rd-mutant) of Salmonella typhimurium is influenced by polymers with covalently linked hydrophobic groups indicating hydrophobic structures accessible at the cell surface . Furthermore, the partition of the R bacteria is influenced by a number of inorganic positive and negative ions, presumably as a consequence of interaction with negatively charged surface structures . In contrast, smooth (S) bacteria and lipopolysaccharide from the parent strain do not seem to participate in either hydrophobic or charge interaction indicating extensive hydrophilicity without charge . Thus, the S-specific polysaccharide side chain of S . typhimurium might serve the purpose of blindfolding aspecific host defence mechanisms dependent on hydrophobicity and charge . On the contrary, the R bacteria and R lipopolysaccharide have physico-chemical properties which predispose to interaction with several types of cells, organelles and molecules. Genetics, 1977 Jun, 86(2 Pt . 1), 237 - 60 Ochre suppression in Salmonella typhimurium; Michalka J et al.; A bacterial strain was constructed which permitted positive selection for ochre suppressor mutations as well as for the loss of suppressor function . A derivative bearing an ochre suppressor mutation was selected following mutagenesis with N-methyl-N-nitroso-N'-nitroguanidine . The suppressor-bearing strain was treated with nitrous acid to eliminate suppressor function by mutation, and a strain lacking suppressor activity was selected . The selected strain which had lost suppressor function was then subjected to mutagenesis to induce a second suppressor mutation . The alternating sequence (induction of an ochre suppressor mutation leads to induction of a mutation eliminating ochre suppressor activity) was repeated 29 and one-half times in a single strain . Some of the suppressor mutations were tentatively mapped at four locations on the chromosome . The first suppressor mutation selected maps at about minute 30 on the chromosome . The second suppressor selected maps at approximately minute 60, while the third suppressor maps nearby, possibly as far as minute 72 . Among the subsequently selected suppressor mutations, all eleven which were mapped were cotransducible with the gal and nic loci near minute 36 on the chromosome and may represent more than one suppressor gene . Deletions were selected which inactivate two of the ochre suppressor alleles mapping near the gal-nic region, suggesting that one or more such genes are dispensable . Some evidence also suggests that the occurrence of either deletion mutations or transduction-mediated recombination events in the gal-nic region can cause instability of nearby suppressor alleles. Eur J Biochem, 1977 Jun 1, 76(1), 41 - 9 Isolation of mutants conditionally blocked in the biosynthesis of the 3-deoxy-D-manno-octulosonic-acid--lipid-A part of lipopolysaccharides derived from Salmonella typhimurium; Lehmann V et al.; A procedure is described for the selection of conditional 3-deoxy-D-manno-octulosonic-acid--Lipid A mutants which depends on temperature sensitivity for both synthesis of complete lipopolysaccharide and for growth . Using this procedure new types of mutants were isolated which cease growth and accumulate lipid A precursors following a shift to nonpermissive temperatures . All precursor molecules differ in their charge as judged by DEAE-cellulose chromatography . While they all contain glucosamine, phosphate and 3-hydroxymyristic acid, they lack detectable 3-deoxy-D-manno-octulosonic acid (dOclA) as well as the nonhydroxylated fatty acids of the complete lipid A structure . Three mutants proved to be conditionally defective in dOclA metabolism, whereas one seems to be blocked at a relatively early step in lipid A synthesis . The phenotypes of all these mutants appear to be due to single mutations by reversion analysis and by characterization of the temperature-resistant revertants . Studies of these mutants may shed light on the essential role of the complete dOclA--lipid A part of lipopolysaccharides in membrane function. Am J Vet Res, 1977 Jun, 38(6), 743 - 7 R factor types found in Salmonella typhimurium and Escherichia coli isolated from calves in a confined environment; Sato G et al.; Typing of R factors by genetic properties was done with Salmonella typhimurium and Escherichia coli isolated from calves on a feedlot where epizootics of clinical or subclinical calf salmonellosis had repeatedly occurred during 5 years . Forty-nine R factors from S typhimurium were fi- (no fertility inhibition) and spp- (no restriction against phage lambda vir) . Twenty-three (46.9%) of them belonged to compatibility group Ialpha and the remainder were nontypable . Fourteen R factors from E coli belonged to different genetic types: fi+ (11=78.6%) and fi- (3=21.4%); spp+ (1=7.1%) and spp- (13=92.9%); compatibility groups FII (5=35.7%), N (1=7.1%), and nontypable (8=57.2%) . In contrast to the R factors of S typhimurium, 9 (64.3%) of the 14 R factors of E coli carried resistance against aminobenzyl penicillin with or without kanamycin resistance . The compatibility groups of R factors of S typhimurium seemed to be useful as a subsidiary epizootiologic marker in this feedlot. Infect Immun, 1977 Jun, 16(3), 1005 - 12 Hepatic clearance of Salmonella typhimurium in silica-treated mice; Friedman RL et al.; Scanning electron microscopy demonstrates that crystalline silica destroys liver Kupffer cells but has no other obvious deleterious effects on the liver . Silica-treated livers still retain the ability to trap large numbers of bacteria perfused through the portal vein even though the rate of clearance is well below normal . In vivo, silica treatment decreases the rate of bacterial clearance from the blood, alters the in vivo organ distribution of cleared bacteria, and decreases the mean lethal dose of Salmonella typhimurium over 100-fold . Cumulatively, the data indicate that silica treatment enhances susceptibility to gram-negative infection, probably by destruction of macrophages. J Clin Invest, 1977 Jun, 59(6), 1188 - 95 Structural features of Salmonella typhimurium lipopolysaccharide required for activation of tissue factor in human mononuclear cells; Rickles FR et al.; Activation of mononuclear cell tissue factor was examined utilizing lipopolysaccharides obtained from wild-type and both Rc and Re mutants of Salmonella typhimurium . Wild-type (smooth) lipopolysaccharide, galactose-deficient (Rc) lipopolysaccharide, heptose-deficient (Re) lipopolysaccharide, and lipid A preparations were all active in their ability to generate tissue factor activity in human mononuclear cells grown in tissue culture . Polymyxin B has been reported to prevent some of the lethal effects of endotoxin in vivo, and the drug reportedly binds to the 2-keto-3-deoxyoctulosonate-lipid A region of the lipopolysaccharide molecule . Polymyxin B was effective in inhibiting the tissue factor generating activity of wild-type lipopolysaccharide, Re lipopolysaccharide, and lipid A in a dose-dependent fashion . Treatment of lipid A preparations with mild alkali abolished the ability of these preparations to activate tissue factor in cells . Analogous to many of the other biologic properties of lipopolysaccharide, tissue factor activation in human mononuclear cells appears to depend upon the integrity of the lipid A portion of the molecule. J Bacteriol, 1977 Jun, 130(3), 983 - 90 Regulation of enzyme synthesis by the glutamine synthetase of Salmonella typhimurium: a factor in addition to glutamine synthetase is required for activation of enzyme formation; Bloom FR et al.; In Klebsiella aerogenes but not in Salmonella typhimurium glutamine synthetase can function during nitrogen-limited growth to increase the rate of synthesis of histidase from the hut genes of S . typhimurium 15-59 (hutS . 15-59) . Formation of proline oxidase is also not increased in nitrogen-limited cultures of S . typhimurium . However, in hybrid strains of Escherichia coli or K . aerogenes, the glutamine synthetase of S . typhimurium activates synthesis of histidase from the hutS . 15-59 genes . Apparently, glutamine synthetase is necessary but not sufficient for activation of transcription of the hut genes; another factor must also be present . This factor is active in both K . aerogenes and E . coli but is missing or altered in S . typhimurium. Science, 1977 May 27, 196(4293), 1000 - 1 Mutagenic activity of nitrite-treated foods: human stomach cancer may be related to dietary factors; Marquardt H et al.; By the Salmonella typhimurium test, extracts of Japanese raw fish treated in the laboratory with nitrite showed mutagenic activity which is prevented by addition of ascorbate . Extracts from similarly treated beef and hot dogs were nonmutagenic . The data conform to a working concept that the high stomach cancer incidence in Japanese and certain other populations may be due to specific dietary factors of an alkylnitrosamide type. Biochemistry, 1977 May 17, 16(10), 2130 - 6 Sodium-dependent methyl 1-thio-beta-D-galactopyranoside transport in membrane vesicles isolated from Salmonella typhimurium; Tokuda H et al.; Membrane vesicles isolated from Salmonella typhimurium G-30 grown in the presence of melibiose catalyze methyl 1-thio-beta-D-galactopyranoside (TMG) transport in the presence of sodium or lithium, as shown initially with intact cells by Stock and Roseman (Stock, J., and Roseman, S . (1971), Biochem . Biophys . Res . Commun . 44, 132) . TMG-dependent sodium uptake is also observed, but only when a potassium diffusion potential (interior negative) is induced across the vesicle membrane . Cation-dependent TMG accumulation varies with the electrochemical gradient of protons generated as a result of D-lactate oxidation, and the vesicles catalyze D-lactate-dependent sodium efflux in a manner which is consistent with the operation of a proton-sodium exchange mechanism . Although the stoichiometry between sodium and TMG appears to be 1:1 when transport is induced by a potassium diffusion potential, evidence is presented which indicates that the relationship may exceed unity under certain conditions . The results are explained in terms of a model in which TMG-sodium (lithium) symport is driven by an electrochemical gradient of protons which functions to maintain a low intravesicular sodium or lithium concentration through proton--sodium (lithium) antiport. Eur J Biochem, 1977 May 2, 75(1), 257 - 66 Isolation, purification and properties of an intermediate in 3-deoxy-D-manno-octulosonic acid--lipid A biosynthesis; Lehmann V; Incomplete lipid A has been purified from a mutant of Salmonella typhimurium which is temperature-sensitive both in synthesis of 3-deoxy-D-manno-octulosonic acid 8-phosphate (dOclA-8-P) and in growth . Pulse-chase experiments have shown that the incomplete lipid A molecule is the intermediate in the biosynthesis of the dOclA-lipid A portion of lipopolysaccharides . The purification procedure included DEAE-cellulose chromatography and electrodialysis . A highly water-soluble precursor material was obtained, consisting of glucosamine, phosphate and 3-hydroxymyristic acid in a molar ratio of 1:1.2:2.1 . Labeling experiments as well as chemical degradation procedures revealed the precursor molecule to be composed of a diphosphorylated glucosamine-disaccharide carrying two amide-linked and two ester-linked 3-hydroxymyristic acids . In contrast to the complete dOclA-lipid A part, the intermediate lacks 3-deoxy-D-manno-octulosonic acid as well as nonhydroxylated fatty acids . On the basis of these findings a pathway for the final steps in dOclA-lipid A biosynthesis is proposed. Appl Environ Microbiol, 1977 May, 33(5), 1184 - 91 Methyl bromide as a microbicidal fumigant for tree nuts; Schade JE et al.; Methyl bromide (MeBr) has broad microbicidal activity, but its use as a disinfectant for food is limited by the resulting bromide residues . Increasing the MeBr concentration, exposure temperature, or exposure period of a treatment tended to increase both the microbicidal efficacy of MeBr and the bromide residues . Its sporicidal activity was less at high than at low relative humidity within the range of 20 to 99% . Both the efficacy and the resulting residues of a MeBr treatment varied inversely with the load of product in a fumigation chamber due to sorption of the fumigant . Fumigation tests with almond kernels inoculated with Escherichia coli or Salmonella typhimurium indicated that MeBr can be used to disinfect whole nut kernels without resulting in excessive bromide residues, although the MeBr level necessary is higher than that normally used for insect control. Infect Immun, 1977 May, 16(2), 493 - 9 Responsiveness of rabbit spleen and appendix cells to bacterial mitogens; Scheffel JW et al.; Rabbit spleen and appendix cells were used to test the mitogenic activity of a commercial lipopolysaccharide (LPS) preparation from Salmonella typhimurium (Difco), a preparation extracted from it, and cell wall preparations from smooth (45/0) and rough (45/20) strains of Brucella abortus . On the basis of {3H}thymidine incorporation ratios (E/C), that is, the incorporation rate among cells treated with the mitogen relative to that of untreated cells, the extracted LPS and both Brucella cell wall preparations, but not the commercial LPS were potent mitogens for rabbit spleen cells . By the same criterion, only the Brucella cell wall preparation produced a significant, but minimally so, response among appendix cells . The weak responsiveness of appendix cells may be more apparent than real, however, and may not imply a difference in intrinsic susceptibility to mitogens by these two populations, because unstimulated appendix cells incorporated thymidine at 10 times the rate of unstimulated spleen cells . Appendix cells, then, may not be susceptible to further stimulation, even by active mitogens . Therefore, the significance of E/C ratios may be equivocal when materials are assayed for mitogenic activity on lymphoid populations whose basal activity is relatively high. J Bacteriol, 1977 May, 130(2), 604 - 9 Influence on motility of Escherichia coli and Salmonella typhimurium by a naturally occurring conjugative plasmid; Bohlin T et al.; In a collection of 45 R-plasmids, one was found to be associated with loss of motility of its Escherichia coli K-12 and Salmonella typhimurium host bacteria when tested in conventional motility agar . Genetic experiments, as well as analyses of deoxyribonucleic acid, showed that inhibition of motility was caused by a conjugative plasmid that was separate from the R-plasmid . This second plasmid, named pUM5, was fi- and mediated the same type of sex pilus (F-like) as the accompanying R-plasmid but lacked resistance determinants . Preliminary studies indicated that bacterial cells carrying the motility inhibition plasmid pUM5 were still equipped with flagella . The mechanism by which flagellar action is disturbed by the plasmid is presently not known. J Bacteriol, 1977 May, 130(2), 577 - 82 Suppression of the DnaA phenotype by mutations in the rpoB cistron of ribonucleic acid polymerase in Salmonella typhimurium and Escherichia coli; Bagdasarian MM et al.; A class of mutations that confer resistance to rifampin in Salmonella typhimurium and Escherichia coli also suppresses the thermosensitivity of chromosome initiation in dnaA mutants . Ribonucleic acid polymerase is resistant to rifampin in vitro in these suppressive mutants, and the suppressors of dnaA cannot be separated from the rpoB mutations by transduction . It is concluded, therefore, that certain rpoB mutations may suppress the DnaA phenotype. Ann Sclavo, 1977 May-Jun, 19(3), 402 - 8 {Ulterior acquisitions regarding the salmonellosis (author's transl)}; Cipolloni AP et al.; The Authors report the results of the bacteriological researches on the incidence of the Salmonella of our zone, after a brief consideration of general aspects salmonellosis . Our observations are refered to 1005 samples of feces of which 84 cases proved positive to Salmonella . It is pointed out that morbidity, represented by Salmonella typhi, paratyphi A and B is low, while it is high for the Salmonella typhimurium and Salmonella enteritidis . The Authors conclude stating that epidemiological situation of salmonellosis still represents a problem of remarkable importance which demands the intensification and the use of efficacious measures of prophylaxis. Poult Sci, 1977 May, 56(3), 1041 - 2 Degeneration of the mucosal surface of the small intestine of the chicken in Salmonella infection; Bayer RC et al.; Day-old chicks were infected with Salmonella typhimurium . The impact on the intestinal mucosa was observed by scanning and transmission electron microscopy . Salmonella infected birds were characterized as having areas on their intestinal mucosal cells devoid of microvilli . The absence of microvilli probably interferes with absorption of the digesta. Zh Mikrobiol Epidemiol Immunobiol, 1977 May, (5), 37 - 42 {Change in the protective activity of the ribosomal fractions of Salmonella typhimurium in mutations in the rfa region and the transduction replacement of the rfb region}; Likhoded VG et al.; It was shown that mutation in the rfa region causing disturbances in the structure of the basal part of the polysaccharide of the cell wall or the absence of O-specific side chains led to the loss of protective activity of the ribosomal fractions isolated from the cells of the murine typhoid salmonella by sedimentation with dihydrostreptomycine sulphate . Ribosomal fractions isolated from the murine typhoid salmonella transductants with the replaced rfb region failed to protect the animals from the infection with the virulent . S . typhimurium, S . enteritidis cultures . The virulence of the mutants and transductants was also changed in comparison with the initial strains. Proc Natl Acad Sci U S A, 1977 May, 74(5), 1932 - 6 Use of a distant reporter group as evidence for a conformational change in a sensory receptor; Zukin RS et al.; A highly sensitive method for demonstrating ligand-induced conformational changes in protein molecules in solution is described . The method utilizes an environmentally sensitive reporter group that is known to be distant from the active site . In the present application a conformational change is demonstrated in the galactose receptor of Salmonella typhimurium, involved in bacterial sensing and transport, by means of an extrinsic fluorophore, 5-iodoacetamidofluorescein, attached at a single methionine residue, and the intrinsic tryptophan fluorophore . Binding of the ligand galactose perturbs the microenvironment of both the fluorescein and tryptophan, as shown by both spectral and potassium iodide quenching changes . The distance between the two dyes is established by fluorescence energy transfer methods to be 41 +/- 10A . Since only one molecule of galactose binds per molecule of receptor and since the galactose molecule is only about 5 A in length, changes at one of these sites reflect the result of an indirect effect . Hence, there must be a ligand-induced conformational change that is propagated a minimum of 30 A through the receptor molecule. Proc Natl Acad Sci U S A, 1977 May, 74(5), 1836 - 40 A gene from Escherichia coli affecting the sigma subunit of RNA polymerase; Harris JD et al.; The RNA polymerase sigma subunits of Escherichia coli K, E . coli C, and Salmonella typhimurium can be resolved by electrophoresis . Using this technique, we have analyzed Salmonella strains carrying F' plasmids from E . coli K in order to map the gene for the sigma factor . Partial diploid analyses show the location of the sigma gene at 62-66 min on the E . coli genetic map . This gene is cotransducible with toIC and dnaG, at 66 min. Proc Natl Acad Sci U S A, 1977 May, 74(5), 1831 - 5 Chromosomal location of a structural gene for the RNA polymerase sigma factor in Escherichia coli; Nakamura Y et al.; A set of F' strains of Escherichia coli K-12 partially diploid for various chromosomal segments has been examined for possible gene dosage effects in the synthesis of sigma factor of the DNA-dependent RNA polymerase (RNA nucleotidyltransferase; nucleoside-triphosphate:RNA nucleoti-dyltransferase, EC 2.7.7.6) . It was found that all F' strains diploid for the dnaG region synthesize sigma at rates two to three times higher than other F' or F- strains . Moreover, strains of Salmonella typhimurium harboring these F' plasmids produce E . coli sigma in addition to Salmonella sigma . This has been shown on the basis of the finding that Salmonella sigma can be precipitated with antiserum against E . coli RNA polymerase but is distinguishable from E . coli sigma in its mobility in sodium dodecyl sulfate/polyacrylamide gel electrophoresis . E . coli sigma polypeptides thus produced seem to be stable in cells of S . typhimurium . These results indicate that a structural gene for sigma (rpoD) is located at the metC-argG region, probably near the dnaG locus (66 min on the current genetic map of E . coli). Cancer Lett, 1977 May, 2(6), 335 - 9 Mutagenicities of protein pyrolysates; Nagao M et al.; Smoke condensate obtained by pyrolysis of proteins, such as lysozyme and histone, was shown to be mutagenic to Salmonella typhimurium TA100 and TA98 . In vitro metabolic activation by a mammaliam postmitochondrial enzyme preparation (S-9 Mix) was required . Smoke condensates obtained by pyrolysis of DNA, RNA, starch and vegetable oil were slightly mutagenic, whereas those from pyrolysis of L- and D-tryptophan and 5-hydroxy-D,L-tryptophan were very strongly mutagenic with metabolic activation by S-9 Mix . Because of the high correlation between mutagenicity and carcinogenicity, it is theorized that the cooking of proteinaceous foods might be an important cause of human cancers. Cancer Lett, 1977 May, 2(6), 319 - 22 Inhibitory effects of selenium of the mutagenicity of 2-acetylaminofluorene (AAF) and AAF derivatives; Jacobs MM et al.; Selenium (Se) decreased the mutagenicity of 2-acetylaminofluorene (AAF), N-hydroxy-2-acetylaminofluorene (N-OH-AAF) and N-hydroxyaminofluorene (N-OH-AF) in the Salmonella typhimurium TA 1538 bacterial tester system . Metabolism of AAF and N-OH-AFF to the active mutagen, N-OH-AF, was accomplished by rat liver extracts . Graded decreases in mutagenicity with increasing Se concentrations were observed for each of the three mutagens . Se decreased the mutagenicity of AAF, N-OH-AAF and N-OH-AF to 65, 68 and 61% of their respective controls with mutagen alone . The effective molar ratios of Se to mutagen yielding these decreases were approximately 10:1 (Se:AAF), 10:1 (Se:N-OH-AAF) and 300:1 (Se:N-OH-AF) . The largest Se effect observed was accomplished by a molar ratio of 100:1 (Se:N-OH-AAF) yielding 28% of the mutagenicity elicited by N-OH-AAF alone. Cancer Lett, 1977 May, 2(6), 305 - 10 The mutagenicity of methylbenzylnitrosamine and its alpha-acetoxy derivatives; Tannenbaum SR et al.; Biological activity of the alpha-acetoxy derivatives of methylbenzylnitrosamine was evaluated using tester strains of Salmonella typhimurium . Compound III, oxidized on the benzyl moiety, was more toxic and more mutagenic than Compound IV, oxidized on the methyl side chain . Compound IV was weakly toxic and was non-mutagenic at the concentrations tested . The presence or absence of the uvrB repair system had no effect on the toxicity of either Compound II or IV . Neither the alpha-oxidized compounds nor the parent nitrosamine reverted the frameshift mutants . As a mutagen, Compound III was approximately as active as N-nitroso compounds not requiring metabolic activation, more active than alpha-acetoxy dialkylnitrosamines and less active than the cyclic alpha-acetoxynitrosopyrrolidine. J Infect Dis, 1977 May, 135(5), 813 - 23 Protective effects of passively transferred immune T- or B-lymphocytes in mice infected with Salmonella typhimurium; Hochadel JF et al.; Purified populations of bone marrow-derived (B-) lymphocytes and thymus-derived (T-) lymphocytes were obtained from C3D2F1 hybrid mice shown to be immune to Salmonella typhimurium . These subpopulations of lymphocytes were injected into normal mice; four days later the animals were challenged with 50 50% lethal doses of S . typhimurium, and viable bacteria in livers, spleens, and blood were counted at various intervals after challenge . On day 8 after challenge, the mice supplemented with B-lymphocytes showed a significant decrease in the number of organisms recovered from all three sites, compared with that seen in recipients of T-lymphocytes and in controls . The mice given B-lymphocytes showed a better rate of survival (65%) than mice that received only T-lymphocytes (21%) or T-lymphocyte fractions contaminated 10%-30% with B-lymphocytes (49%) . These data indicate that, although the humoral response is not totally protective, it does play an important role in the suppression of the infection during its early stages. Cancer Res, 1977 May, 37(5), 1468 - 75 Comparative electrophilicity, mutagenicity, DNA repair induction activity, and carcinogenicity of some N- and O-acyl derivatives of N-hydroxy-2-aminoflourene; Bartsch H et al.; N-Myristoyloxy-N-acetyl-2-aminofluorene, N-acetoxy-N-myristoyl-2-aminofluorene, N-myristoyloxy-N-myristoyl-2-aminofluorene, and N-hydroxy-N-myristoyl-2-aminofluorene each yielded a high incidence of sarcomas in male rats within 5 to 7 months after s.c . injection of 64 micronmoles in divided doses . N-Acetoxy-N-acetyl-2-aminofluorene and N-hydroxy-2-acetylaminofluorene, although potent carcinogens at the s.c . site, were less active than the above derivatives with a myristoyl substituent . N-Sulfonoxy-N-acety--2-aminofluorene (purity larger than or equal to 70%) had little or no carcinogenic activity when administered in large amounts by s.c . injection to rats . The low incidence of tumors could have resulted from N-hydroxy-2-acetylaminofluorene or other decompostion products of the N-sulfonozy derivative . Each of the N-acetoxy and N-myristoyloxy derivatives of N-acetyl-2-aminofluorene and of N-myristoyl-2-aminofluorene showed electrophilic activity toward methionine; N-acetoxy-N-acetyl-2-aminofluorene was the most reactive and N-myristoyloxy-N-myristoyl-2-aminofluorine was the least reactive . Each of these esters also induced unscheduled tritiated thymidine incorportation in nondividing cultured human fibroblasts and thus appeared to induce lesions in DNA that lead to repair synthesis.EACH OF THE N-acetoxy derivatives was highly mutagenic for Salmonella typhimurium strains TA98 and TA1538 without tissue activation; neither N-myristoyloxy derivative was mutagenic under these conditions . While there was a qualitative correspondence between several of the above activities of these 2-aminofluorene derivatives, the quantitative differences and the lack of detectable mutagenicity of the 2N-myristoyloxy derivatives for S . typhimurium indicate the need for multiple short-term tests in the qualitative prediction of potential carcinogenic activity. Mutat Res, 1977 May, 43(2), 159 - 64 Asbestos and glass fibres in bacterial mutation tests; Chamberlain M et al.; Asbestos fibres are carcinogenic in man and experimental animals but fine glass fibres are known, at present, only to be carcinogenic in experimental animals . Asbestos and glass fibres have been studied in mutation tests using auxotrophic strains of Escherichia coli and Salmonella typhimurium . The mutagenic activities of the positive control mutagens ultraviolet light, potassium chromate, ethyl methanesulphonate and benzo(a)pyrene were detected in the experiments . However, no mutagenic activity was found to be associted with any of the asbestos and glass fibres tested over a wide range of concentrations . The implications of these findings for the mode of action of asbestos and glass fibres as carcinogens are discussed. Anesthesiology, 1977 May, 46(5), 346 - 50 Mutagenicity of halogenated ether anesthetics; Baden JM et al.; An in vitro microbial assay system employing two histidine-dependent strains of Salmonella typhimurium, TA1535 and TA100, was used to test the mutagenicities of enflurane, methoxyflurane, isoflurane and fluroxene . Enflurane, isoflurane and fluroxene in concentrations ranging from 0.01 to 30 per cent and methoxyflurane in concentrations ranging from 0.01 to 7 per cent were incubated with bacteria in the presence or absence of homogenates of liver prepared from rats pretreated with the enzyme inducer, Aroclor 1254 . Enflurane, methoxyflurane, isoflurane, and urines from patients anesthetized with these agents were not mutagenic . Fluroxene, however, was highly mutagenic, and therefore poses a possible hazard for operating room personnel and patients. J Biol Chem, 1977 Apr 25, 252(8), 2793 - 5 Identification of a gamma-glutamyl methyl ester in bacterial membrane protein involved in chemotaxis; Van Der Werf P et al.; Evidence is presented that a methyltransferase enzyme, previously shown to be necessary for chemotaxis and identified as the cheR gene product, catalyzes the formation of a gamma-glutamyl methyl ester in one or more membrane proteins of Salmonella typhimurium . The rates of release of methyl label from the methylated protein in acid, base, and hydroxylamine are consistent with a methyl ester and not with a methylated imidazole, guanidino, or amino group . A gamma-glutamyl methyl ester was isolated from a proteolytic digest of the modified protein. Biochemistry, 1977 Apr 5, 16(7), 1443 - 51 Nuclear magnetic resonance and fluorescence studies of substrate-induced conformational changes of histidine-binding protein J of Salmonella typhimurium; Robertson DE et al.; The histidine-binding protein J of Salmonella typhimurium binds L-histidine as a first step in the high-affinity active transport of this amino acid across the cytoplasmic membrane . High-resolution nuclear magnetic resonance spectroscopy has been used to monitor the conformation of histidine-binding protein J in the presence and absence of substrate . Evidence is presented to show that this binding protein undergoes a conformational change involving a substantial number of amino-acid residues (including tryptophans) in the presence of L-histidine and that this change is specific for L-histidine . In order to monitor the involvement of tryptophan residues in the substrate-induced conformational change, 5-fluorotryptophan has been incorporated biosynthetically into the histidine-binding protein J using a tryptophan autotroph of Salmonella typhimurium . There are no significant differences in the conformation and binding activity between the 5-fluorotryptophan-labeled and the normal histidine-binding protein J . Proton and fluorine-19 nuclear magnetic resonance studies of the 5-fluorotryptophan-labeled binding protein show that at least one (and possibly two) of the tryptophan residues undergo(es) a change toward a more hydrophobic environment in the presence of L-histidine . These observations are supported by fluorescence data and by differences in the reactivity of the tryptophan residues of this protein toward N-bromosuccinimide in the presence and absence of substrate . The present results are consistent with models for the action of periplasmic-binding proteins in shock-sensitive transport systems of gram-negative bacteria which require a substrate-induced conformational change prior to the energy-dependent translocation of substrates. Mutat Res, 1977 Apr, 48(2), 121 - 9 Mutagenicities of N-nitrosamines on Salmonella; Yahagi T et al.; The mutagenic activities of 11 N-nitrosamines were tested using Salmonella typhimurium TA100 and TA98 . All the carcinogenic N-nitrosamines were mutagenic on TA100 with a drug-activating system from the rat liver, whereas N,N-diphenylnitrosamine, a non-carcinogen, was not mutagenic . None of the N-nitrosamines was mutagenic on TA98, except N,N-diethylnitrosamine which was weakly mutagenic . To detect the mutagenicity of N,N-dimethylnitrosamine, the pre-incubation of bacteria and N,N-dimethylnitrosamine with S-9 Mix before if was poured onto plates was obligatorily required . Dimethyl sulfoxide inhibited the mutagenic effect of N,N-dimethylnitrosamine. Mikrobiyol Bul, 1977 Apr, 11(2), 287 - 90 {Salmonella typhimurium isolated from the spinal fluid of 2 children}; Meco O et al.; In this article isolation of S . typhimurium bacteria from cebrospinal fluid of two children is reported. Mutat Res, 1977 Apr, 48(2), 237 - 48 Detection of mutagenic activity in particulate air pollutants; Tokiwa H et al.; Ames's strains of Salmonella typhimurium were used to evaluate the mutagenic activity of airbone particulate materials collected at six different points in the industrial area of Ohmuta and the residential area Fukuoka . Tests were done in presence of rat-liver S-9 fraction isolated from rats that had been treated with Aroclor 1254 . When the number of revertant colonies per plate was plotted against the amount of methanol extract of particulate air pollutants, using strain TA98, approximately linear relationships were observed for active samples . Generally, mutagenic activity of the samples increased in proportion to the density of air pollutants . In our system, 38--349 microng of methanol extract, from 0.225--4.51 m3 of air from the factory districts in Ohmuta City gave 100 his+ revertants per plate . On the other hand, 54--2300 microng of air pollutants, from 1.29--14.1 m3 of air from the residential districts in Fukuoka City, gave a comparable activity . Every sample from each area had mutagenic activity . Chemicals in air pollutants were fractionated by alumina column chromatography and identified by gas chromatography and mass spectrometry . More than 28 compounds, including 12 unknown substances were identified as polycyclic hydrocarbons . Twelve of these compounds are already known to be carcinogens and to induce reversions to histidine independence in strain TA98 of Salmonella. Mutat Res, 1977 Apr, 48(2), 145 - 53 Mutagenicity of anti-cancer nitrobenzofuroxans; Thompson S et al.; Anti-leukaemically active benzofuroxans were tested for mutagenicity in Salmonella typhimurium . Mutagenicity was not found to be correlated to the previously established anti-leukaemic activity . One anti-leukaemically inactive compound after exposure to liver microsomal enzymes proved the most mutagenic of the derivatives for TA100, whereas after similar treatment, the mutagenicity of the most potent anti-leukaemic compound was reduced . All twelve derivatives tested were mutagenic in a base-substitution strain which was defective in excision-repair and also carried a plasmid-linked repair deficiency . Mutagenicity of five dervatives was undetectable in strains proficient for one or the other of the above repair pathways . Nine of the benzofuroxans could also be detected as mutagens in the frameshift tester strain TA98. Mutat Res, 1977 Apr, 48(2), 139 - 43 Relative efficiencies of a series of square-planar plantinum(II) compounds on Salmonella mutagenesis; Lecointe P et al.; Twelve Pt(II) compounds have been tested for mutagenicity on Salmonella typhimurium (strain TA 100) . Very high mutagenic activities were found for the cis derivatives . A correlation is suggested between these results and a formerly described model of chemical reactivity towards DNA, according to which cis derivatives from intra-strand chelates with guanine . A smaller activity was found with monodentate complexes with DNA. Mutat Res, 1977 Apr, 46(2), 53 - 6 The use of rec-bacteria for testing of carcinogenic substances; Ichinotsubo D et al.; A series of rec-Escherichia coli strains were tested for their sensitivity to four known carcinogenic compounds by examination of a zone of inhibited bacterial growth around a central well containing the test chemical . The mutants recA-, recB-, recC-, and recA- recB- recC- were all more sensitive to the mutagens than the parental strain AB1157 . The recB- recC- strain was examined with a larger series of compounds and was found to respond to many of the substances in a similar way as the Salmonella typhimurium strains of Ames but with some notable exceptions . Nitrosamines, with rat liver microsomal activation, could be detected at lower levels and a group of aromatic amino compounds failed to react with these rec-E . coli . An unusual feature of these rec-mutants is their sensitivity to mixtures of nitrosamines and 2-acetyl amino-fluorene in the absence of microsomal activation. Appl Environ Microbiol, 1977 Apr, 33(4), 947 - 54 Use of enzyme-labeled antibodies to detect Salmonella in foods; Krysinski EP et al.; An indirect enzyme-labeled antibody technique (ELAT), in which Salmonella typhimurium was used as a model, was developed as a method to detect Salmonella in food samples . A cellulose-acetate membrane filter, the matrix for detection, was placed on a membrane-filter base and overlaid with a multiwelled lucite template . Mixed broth enrichment cultures were dispensed in the template wells, and cells were spotted onto the membrane via suction . After fixation, the membranes were immersed in rabbit anti-S . typhimurium flagella antibody, washed, immersed in goat anti-rabbit antibody conjugated to peroxidase, and washed . Exposure of membranes to the substrates 3,3'-diaminobenzidine or benzidine resulted in development of brown or blue macroscopic reaction products, respectively, on spots containing S . typhimurium . ELAT results agreed with those of enrichment serology and cultural procedures on three food products containing known levels of S . typhimurium . Because of the magnification effect of the enzyme-substrate reaction, fewer cells were needed for detection than with enrichment serology, thereby reducing the total analysis time . The ability to test 14 or more samples simultaneously on a 47-mm membrane filter would facilitate screening large number of samples . Pending the development of a pure H antisera pool for the common Salmonella serotypes free from O antibodies, the ELAT demonstrated potential as a Salmonella detection methodology. Zh Mikrobiol Epidemiol Immunobiol, 1977 Apr, (4), 86 - 91 {Change in phagocytic activity toward the agent of tularemia in highly sensitive animals with mixed infections}; Dunaeva TN et al.; An increase of the ingestive and digestive capacity of neutrophils to the homologous causative agent and tularemia microbe was revealed by the opsonophagocytic test in Microtus arvalis, albino mice and guinea pigs infected with sublethal Yersinia pseudotuberculosis and Salmonella typhimurium doses . In subsequent tularemia infection some of the animals displayed a reduction of the septicemia intensity, prolongation of the disease and elevation of the susceptibility threshold . Period of manifestation of the inhibitory action on tularemia coincided with that of the increase in phagocytic activity Proc Natl Acad Sci U S A, 1977 Apr, 74(4), 1535 - 7 Inhibition of histidyl-tRNA-adenosine triphosphate phosphoribosyltransferase complex formation by histidine and by guanosine tetraphosphate; Kleeman JE et al.; Formation of the complex between the first enzyme of histidine biosynthesis from Salmonella typhimurium, ATP phosphoribosyltransferase {1-(5'-phosphoribosyl)-ATP: pyrophosphate phosphoribosyltransferase; EC 2.4.2.17}, and histidyl-tRNA is shown to be inhibited by L-histidine and by guanosine-5'-diphosphate-3'-diphosphate in the presence of histidine . Higher histodine levels make guanosine tetraphosphate a more effective inhibitor . Relatively high concentrations of guanosine-5'-triphosphate also inhibit complex formation, but this inhibition is not enhanced by histidine . The possible implications of these observations with respect to the gene regulatory activity of this enzyme are discussed. J Bacteriol, 1977 Apr, 130(1), 347 - 53 Degradation of Escherichia coli beta-galactosidase fragments in protease-deficient mutants of Salmonella typhimurium; Miller CG et al.; The degradation rates of several mutationally generated fragments of Escherichia coli beta-galactosidase were determined in wild-type strains of Salmonella typhimurium and in mutant Salmonella strains lacking several proteases and peptidases . Three termination fragments (produced by lacZ545, lacZ521, and lacZX90) and one internal reinitiation (restart) fragment {lacZpi(1)} are degraded in wild-type Salmonella strains at the same rates observed in wild-type Escherichia coli strains . Mutations that lead to loss of peptidases N, A, B, P, and Q or to loss of protease I or II do not affect the decay rates of any of these fragments . In addition, all of these peptidases and proteases are present in E coli mutants carrying deg mutations (deg mutations are known to stabilize beta-galactosidase fragments) . Apparently, none of the proteases and peptidases that are currently accessible to direct genetic analysis plays a role in the early steps of the degradation of protein fragments. J Bacteriol, 1977 Apr, 130(1), 223 - 31 Chemotactic mechanism of Salmonella typhimurium: preliminary mapping and characterization of mutants; Warrick HM et al.; Some new, generally nonchemotactic mutants of Salmonella typhimurium were isolated and they, together with previously isolated mutants and some from other investigators, were mapped . Most of the mutants were classified in nine complementation groups, which are probably individual genes . Of these, five map at the end of the flagella region and appear in the order motB-(cheWcheP)-cheX-cheQ-cheR-flaC . Two of the mutations, cheU and cheV, map in the flaQ and flaAII genes, respectively . The remaining genes, cheS and cheT, have not yet been mapped . Most of the mutants are phenotypically smoothly swimming, but some are constantly tumbling . Two of the groups show dominant behavior as recipients in genetic crosses; the rest are recessive . The mutants vary in their responses to stimuli but, since their responses to all chemoeffectors are abnormal, the central processing, rather than individual, receptors must be impaired . The two mutations that coincide with genes for flagella probably involve the locus of the final delivery of sensing signal to the flagella. J Bacteriol, 1977 Apr, 130(1), 420 - 8 Regulation of two phosphatases and a cyclic phosphodiesterase of Salmonella typhimurium; Kier LD et al.; The regulation of three Salmonella typhimurium phosphatases in reponse to different nutritional limitations has been studied . Two enzymes, an acid hexose phosphatase (EC 3.1.3.2) and a cyclic phosphodiesterase (EC 3.1.4.d), appear to be regulated by the cyclic adenosine 3' ,5'-monophosphate (AMP) catabolite repression system . Levels of these enzymes increased in cells grown on poor carbon sources but not in cells grown on poor nitrogen or phosphorus sources . Mutants lacking adenyl cyclase did not produce elevated levels of these enzymes in response to carbon limitation unless cyclic AMP was supplied . Mutants lacking the cyclic AMP receptor protein did not produce elevated levels of these enzymes in response to carbon limitation regardless of the presence of cyclic AMP . Since no specific induction of either enzyme could be demonstrated, these enzymes appear to be controlled solely by the cyclic AMP system . Nonspecific acid phsphatase activity (EC 3.1.3.2) increased in response to carbon, nitrogen, phosphorus, or sulfur limitation . The extent of the increase depended on growth rate, with slower growth rates favoring greater increases, and on the type of limitation . Limitation for either carbon or phosphorus resulted in maximum increases, whereas severe limitation of Mg2+ caused only a slight increase . The increase in nonspecific acid phosphatase during carbon limitation was apparently not mediated by the catabolite repression system since mutants lacking adenyl cyclase or the cyclic AMP receptor protein still produced elevated levels of this enzyme during carbon starvation . Nor did the increase during phosphorus limitation appear to be mediated by the alkaline phosphatase regulatory system . A strain of Salmonella bearing a chromosomal mutation, which caused constitutive production of alkaline phosphatase (introduced by an episome from Escherichia coli), did not have constitutive levels of nonspecific acid phosphatase. J Bacteriol, 1977 Apr, 130(1), 399 - 410 Resolution and purification of three periplasmic phosphatases of Salmonella typhimurium; Kier LD et al.; A survey of Salmonella typhimurium enzymes possessing phosphatase or phosphodiesterase activity was made using several different growth conditions . These studies revealed the presence of three major enzymes, all of which were subsequently purified: a cyclic 2' ,3'-nucleotide phosphodiesterase (EC 3.1.4.d), an acid hexose phosphatase (EC 3.1.3.2), and a nonspecific acid phosphatase (EC 3.1.3.2) . A fourth enzyme hydrolyzed bis-(p-nitrophenyl)phosphate but none of the other substrates tested . No evidence was found for the existence of an alkaline phosphatase (EC 3.1.3.1) or a specific 5'-nucleotidase (EC 3.1.3.5) in S . typhimurium LT2 . All three phosphatases could be measured efficiently in intact cells, which suggested a periplasmic location; however, they were not readily released by osmotic shock procedures . The nonspecific acid phosphatase, which was purified to apparent homogeneity, yielded a single polypeptide band on both sodium dodecyl sulfate and acidic urea gel electrophoretic systems. J Bacteriol, 1977 Apr, 130(1), 192 - 9 Transcription of the hut operons of Salmonella typhimurium; Cooper TG et al.; We have measured, by ribonucleic acid-deoxyribonucleic acid hybrid formation, the amounts of hut-specific ribonucleic acid contained in extracts of various mutant strains of Salmonella typhimurium . Our data are consistent with a model in which regulation of Hut enzyme production occurs at the level of transcription and support earlier genetic evidence indicating that all of the hut genes are transcribed in the clockwise direction on the S . typhimurium chromosome . These results also suggest that promoter sites of the two hut operons may differ in their ability to initiate transcription. Cancer Res, 1977 Apr, 37(4), 1112 - 4 Light-induced mutagenicity of neutral red (3-amino-7-dimethylamino-2-methylphenazine hydrochloride); Gutter B et al.; Illumination of Salmonella typhimurium in the presence of neutral red (3-amino-7-dimethylamino-2-methylphenazine hydrochloride) results in mutations of the base substitution type. Mutat Res, 1977 Apr, 48(2), 225 - 36 Nitrosation in vitro and in vivo by sodium nitrite, and mutagenicity of nitrogenous pesticides; Seiler JP; 37 nitrogenous pesticides, belonging to the chemical groups of amides, carbamates and ureas, were nitrosated with sodium nitrite in vitro . The nitrosated compounds were tested for mutagenic activity in the bacterial spot test with Salmonella typhimurium his G 46 . Those pesticides reacting positively in this test after nitrosation were then fed to mice in combination with sodium nitrite in order to assess the formation and mutagenicity of these nitroso compounds in vivo . With the already known exception of ethylenethiourea (ETU), no pesticide produced enhanced numbers of micronuclei in mouse bone-marrow erythrocytes when fed together with nitrite . Dose-response experiments with intraperitoneal injection of N-nitroso-ETU revealed an apparent no-effect level of about 15--18 mg/kg . The findings are correlated with the pesticide residues actually present in the environment. Mutat Res, 1977 Apr, 48(2), 131 - 8 Mutagenicity of 22 N-nitrosamides and related compounds for Salmonella typhimurium TA1535; Lee K et al.; Twenty-two N-nitrosamides and related compounds, including 14 nitrosoureas, 5 nitrosocarbamates, and one nitrosocyanamide, were tested at various concentrations for mutagenic activity towards Salmonella typhimurium TA1535 without the use of microsomes . The ether-water partition coefficient, solubility in water, and half-life in aqueous solution were also measured . Twenty compounds were mutagenic, with "standard mutagenic concentrations" (i.e . those producing 100 mutants/dish) of 0.0024--6500 micron . Standard mutagenic concentration was negatively correlated with the partition coefficient . Three compounds (ethyl 2-acetoxyethylnitrosocarbamate, nitrosocarbaryl, and methylnitrosobenzamide) were more active than the classic mutagen methylnitrosonitroguanidine . Nitrosocarbamates were at least 50 times more mutagenic than the corresponding nitrosoureas . Nitrosodihydrouracil and propylene-nitrosourea were more active than related compounds . Ethylnitrosocyanamide was 730 times more mutagenic than ethylnitrosourea . Fifteen of the test compounds (of which 14 were mutagenic) had previously been assayed in rats for carcinogenicity, all with positive results. Proc Natl Acad Sci U S A, 1977 Apr, 74(4), 1662 - 6 The product of a newly identified gene, gInF, is required for synthesis of glutamine synthetase in Salmonella; Garcia E et al.; The product of a newly identified gene, glnF, which is distinct from the glutamine synthetase structural gene (glnA), is required for synthesis of glutamine synthetase {L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.2{ in Salmonella typhimurium and probably in Escherichia coli . Salmonella strains with ICR (2-chloro-6-methoxy-9-{3-(2-chloroethyl)aminopropylamino}acridine dihyodrochloride)-induced (frameshift) mutations in glnF are glutamine auxotrophs; they have less than 10% oof wild-type glutamine synthetase activity or antigen and are unable to derepress the synthesis of the enzyme . The mutant allele is recessive to the wild-type allele, indicating that the glnF gene encodes a diffusible product . Mutant glnF strains have normal activities of all proteins involved in covalent modification of glutamine synthetase: adenylyltransferase (EC 2.7.7.42), PII, uridylyltransferase, and uridylyl removing enzyme . In addition, they have glutamate synthase (EC 1.4.1.13) and glutamate dehydrogenase (EC 1.4.1.4) activities . Thus, glnF does not encode the structure of any of these proteins . The above evidence suggests that the product of the glnF gene is (or produces) a positive regulatory factor that is required for synthesis of glutamine synthetase; it indicates that auto-regulation cannot account for control of the synthesis of glutamine synthetase in Salmonella. J Bacteriol, 1977 Apr, 130(1), 411 - 9 Properties of two phosphatases and a cyclic phosphodiesterase of Salmonella typhimurium; Weppelman R et al.; The properties of three phosphatases from Salmonella typhimurium have been examined . A cyclic 2',3'-nucleotide phosphodiesterase (EC 3.1.4.d) hydrolyzes cyclic 2',3'-purine and -pyrimidine nucleotides, as well as 3'-mononucleotides, and has a pH optimum of about 7.5 . It requires divalent cations for activity and has a molecular weight of 67,000 . Acid hexose phosphatase (EC 3.1.2.2) possesses activity towards hexose phosphates as well as other sugar phosphates . The enzyme is apparently a dimer of 37,000-dalton subunits . Nonspecific acid phosphatase (EC 3.1.3.2) hydrolyzes a variety of phosphate esters, including nucleotides and sugar phosphates . The enzyme also hydrolyzes the phosphoric anhydride bonds of pyrophosphate and nucleotides . Michaelis constants of the nonspecific acid phosphatase for several of its substrates are in the 1 to 2 mM range . Nonspecific acid phosphatase is a dimer of 27,000-dalton subunits. Biochim Biophys Acta, 1977 Mar 29, 497(1), 323 - 8 The origin of the sulfur atom in thiamine; Bellion E et al.; The mode of biosynthesis of the thiazole moiety of thiamine, 4-methyl-5beta-hydroxyethyl thiazole (MHET) was studied using Salmonella typhimurium as test organism . It was shown by isotope incorporation experiments, that the sulfur atom, but not carbon-3, of cysteine is incorporated into MHET, indicating a separation of the sulfur atom of cysteine from the carbon chain during incorporation . Isotope competition experiments revealed that the incorporation of {35S}cysteine is not significantly diluted by the presence of methionine, homocysteine, and glutathione . No incorporation of label from {14C}glutamate and {14C}formate was observed, leaving the origin of the five-carbon unit still in doubt. Biochim Biophys Acta, 1977 Mar 18, 475(2), 267 - 75 Partial derepression of the isoleucine-valine enzymes during methionine starvation is Salmonella typhimurium; Rizzino A et al.; Methionine starvation of methionine auxotrophs in the presence of excess branched-chain amino acids results in a partial derepression of the isoleucine and valine enzymes . Reversed-phase chromatography indicated that isoleucine, valine and leucine tRNA were altered during methionine starvation . In addition, the total tRNA isolated from cells under these conditions were undermethylated . The observed derepression may be caused by the inability of methyl-deficient tRNA's to participate adequately in normal regulatory functions. Mol Gen Genet, 1977 Mar 7, 151(2), 121 - 6 Detection of messenger RNA from the isoleucine--valine operons of Salmonella typhimurium by heterologous DNA-RNA hybridization: involvement of transfer RNA in transcriptional repression; Childs G et al.; A hybridization assay using Escherichia coli K-12 DNA isolated from the specialized transducing bacteriophage gammaCI857St68h80 dilv was used to examine the rate of synthesis of the messenger RNA's (mRNA) derived from the isoleucine-valine (ilv) gene cluster of Salmonella typhimurium . In all cases examined, changes in ilv enzyme levels could be correlated with changes in the rate of synthesis of ilv mRNA . Several well characterized regulatory mutants of S . typhimurium had rates of synthesis of ilv mRNA 3 to 8-fold higher than the repressed wild-type strain . The increased rates of ilv mRNA synthesis found in a hisT strain as well as in isoleucyl-and leucyl-tRNA SYNTHETASE MUTANTS, STRONGLY SUGGESTS A ROLE FOR BRANCHED-CHAIN AMINOACYL-TRNA's in transcriptional control. Infect Immun, 1977 Mar, 15(3), 842 - 5 Mitogenic activity of cell wall components from smooth and rough strains of Brucella abortus; Kreutzer DL et al.; On the basis of {3H}thymidine incorporation by normal mouse spleen cell cultures, cell wall preparations from a smooth (45/0) strain and a rough (45/20) strain of Brucella abortus were strongly mitogenic . On the other hand, none of several subcomponents extracted from the cell wall preparations, including aqueous and phenolic lipopolysaccharides, was active . These results contrast with the marked mitogenic activity of lipopolysaccharides isolated from other gram-negative bacteria such as Salmonella typhimurium. Tubercle, 1977 Mar, 58(1), 13 - 8 Fatal generalized BCG histiocytosis; Doleckova V et al.; An infant was vaccinated at the age of 3 days with BCG vaccine . At the age of 3 years 10 months he developed an infection by Salmonella typhimurium . The infection persisted with recurrent episodes of fever, peri-nephritic abscess, abscesses of lymph nodes, hepatomegaly, splenomegaly and paravertebral and retro-peritoneal abscesses, from which Salmonella were isolated . At the age of 6 years and 2 months later . At post-mortem examination there were widespread histiocytic nodules in many organs, from which Mycobacterium bovis BCG were cultured . One previous case has been reported from Czechoslovakia . The mother of that child was the sister of the father of the child reported here . It was not possible to investigate the possibility of abnormalities of humoral or cellular immunity in the family. Mutat Res, 1977 Mar, 42(3), 335 - 42 Mutagenicities of quinoline and its derivatives; Nagao M et al.; Quinoline, recently reported to be carcinogenic in rats {12}, was mutagenic to Salmonella typhimurium tester strains TA100 and TA98 in the presence of the metabolic activation system S-9 mix . 2-Chloroquinoline, a non-carcinogen {12}, was non-mutagenic with or without S-9 mix . 8-Hydroxyquinoline, which is t known to be carcinogenic, was mutagenic with S-9 mix to both bacterial strains . The mutagenicities of 17 other quinoline derivatives that are not known to be carcinogenic were tested, and 12 of these compounds were mutagenic. Infect Immun, 1977 Mar, 15(3), 950 - 7 Role of zinc in the abatement of hepatocellular damage and mortality incidence in endotoxemic rats; Sobocinski PZ et al.; Intraperitoneal administration of zinc (ZnIP) as zinc chloride prior to or simultaneously with a lethal quantity of intraperitoneally administered Salmonella typhimurium endotoxin significantly protected rats against toxin-induced mortality and hepatocellular damage . Pretreatment with amounts of zinc chloride ranging from 0.4 to 2.0 mg/100 g of body weight resulted in 80 to 100% survival compared with 10% survival in untreated control rats at 24 h after endotoxin treatment . Zinc chloride treatment in excess of 2.0 mg/100 g of body weight appeared to be toxic and provided diminished protection . In contrast with the protection obtained with ZnIP, intravenously administered zinc did not provide protection . The effectiveness of ZnIP to enhance survival if it was given after endotoxin was greatly diminished as a function of time after endotoxin . The extent of hepatocellular damage was assessed at various times after endotoxin administration in ZnIP-treated and untreated rats by measurement of plasma ornithine carbamoyltransferase activity and histological examination of liver sections . Endotoxin absorption from the peritoneal cavity and hepatic uptake were studied by using 51Cr-labeled endotoxin . ZnIP pretreatment significantly reduced 51Cr-labeled endotoxin content of blood and liver when compared to untreated controls, and effectively prevented endotoxin-induced elevations in plasma ornithine carbamoyltransferase activity and hepatic tissue necrosis . These data indicate that protection afforded by ZnIP treatment results as a consequence of the ability of zinc to diminish absorption of the toxin from the peritoneal cavity and subsequent hepatic uptake. J Virol, 1977 Mar, 21(3), 956 - 64 Regulation of Bacteriophage P22 DNA synthesis and repressor levels in P22cly infections; Tokuno SI et al.; A rifampin-resistant mutant of Salmonella typhimurium carries an altered RNA polymerase . Wild-type (c+) phage P22 displays clear plaques and a reduced lysogenization frequency on this mutant host . The cly mutants of P22 were isolated on the basis of their ability to lysogenize such mutant hosts . Two classes of regulatory events, both of which are dependent on P22 gene c1 activity, are necessary for the establishment of lysogeny in P22 . The positive events culminate in repressor synthesis; the negative events cause a retardation in phage DNA synthesis . Neither the positive nor the negative events are observed in P22c+ infections of the mutant host . Both effects are found in P22cly infections of the mutant host . Observable results of both the negative and the positive events are exaggerated in P22cly infections of wild-type hosts as compared to P22c+ infections . The cly mutation apparently increases the positive and negative regulatory events so that they are detectable in the mutant host and exaggerated in wild-type hosts . Possible mechanisms that result in the high frequency of lysogenization that characterizes the cly mutation and the nature of the cly mutation are discussed. J Bacteriol, 1977 Mar, 129(3), 1601 - 6 Physical characterization of a plasmid cointegrate containing an F'his gnd element and the Salmonella typhimurium LT2 cryptic plasmid; Manis JJ et al.; A recombinant plasmid (pAS19) isolated from a derivative of Salmonella typhimurium LT2, containing the strain LT2 cryptic plasmid and an F'his gnd element, has been physically characterized . The pAS19 plasmid contour length equals the sum of the contour lengths of the cryptic plasmid and F'his gnd element . Deoxyribonucleic acid (DNA)-DNA hybridization experiments demonstrated that whereas the pAS19 plasmid exhibits extensive DNA homology with both the cryptic plasmid and the F'his gnd element, there is little DNA homology between these latter two plasmids . The DNA fragmentation pattern of the pAS19 plasmid produced by the restriction endonuclease R-EcoRI is consistent with that expected for a composite plasmid cointegrate containing most, if not all, of the DNA sequences present in its two component plasmids. J Bacteriol, 1977 Mar, 129(3), 1289 - 97 Fine-structure map of the histidine transport genes in Salmonella typhimurium; Ames GF et al.; Afine-structure genetic map of the histidine transport region of the Salmonella typhimurium chromosome was constructed . Twenty-five deletion mutants were isolated and used for dividing the hisJ and hisP genes into 8 and 13 regions respectively . A total of 308 mutations, spontaneous and mutagen induced, have been placed in these regions by deletion mapping . The histidine transport operon is presumed to be constituted of genes dhuA, hisJ, and hisP, and the regulation of the hosP and hisJ genes by dhuA is discussed . The orientation of this operon relative to purF has been established by three-point crosses as being: purF duhA hisJ hisP. Infect Immun, 1977 Mar, 15(3), 997 - 8 Effectiveness of parenteral and oral typhoid vaccination in mice challenged with a Salmonella typhi-Salmonella typhimurium hybrid; Diena BB et al.; Live Salmonella typhi administered intraperitoneally, acetone-killed S . typhi administered intraperitoneally, and live S . typhi given orally, with their effectiveness decreasing in that order, protected Swiss white mice against death from challenge with a virulent Salmonella typhimurium hybrid expressing S . typhi antigens. Infect Immun, 1977 Mar, 15(3), 988 - 92 Neutralization of Salmonella toxin-induced elongation of Chinese hamster ovary cells by cholera antitoxin; Sandefur PD et al.; A partially purified preparation of the delayed skin permeability factor from Salmonella typhimurium caused Chinese hamster ovary cells to elongate . The elongation effect and the skin test activity were blocked by monospecific rabbit antisera against cholera toxin and against the B fragment of cholera toxin, Cancer Lett, 1977 Mar, 2(4-5), 221 - 6 Mutagenicities of smoke condensates and the charred surface of fish and meat; Nagao M et al.; Smoke condensates obtained from broiling fish showed mutagenic activity for Salmonella typhimurium TA100 and TA98 . Metabolic activation was required to induce mutagenic activity of smoke condensates of some species of fish . The smoke condensate obtained during charcoal broiling of beefsteak was far less mutagenic than that of fish, with or without metabolic activation . Extracts of the charred surface of broiled fish and meat also contained mutagenic substances . These extracts needed metabolic activation to exhibit mutagenicities on TA98 . The mutagenic activity of the smoke condensate obtained from one sardine weighing 100 g was equivalent to that of 132 micrograms benzo(a)pyrene and that of the charred surface of the sardine was equivalent to 358 micrograms benzo(a)pyrene . One piece of beefsteak weighing 190 g, contained mutagenic activity equivalent to that of 855 micrograns benzo(a)pyrene. J Bacteriol, 1977 Mar, 129(3), 1387 - 96 Ornithine transcarbamylase from Salmonella typhimurium: purification, subunit composition, kinetic analysis, and immunological cross-reactivity; Abdelal AT et al.; Ornithine transcarbamylase (OTCase) was purified to hemogeneity from a derepressed strain of Salmonella typhimurium . The optimal pH for enzyme activity is 8.0 . The molecular weight of the enzyme was calculated to be 116,000, based on measurements of the sedimentation coefficient by sucrose gradient ultracentrifugation and the Stokes radius by gel filtration . Polyacrylamide gel electrophoresis of cross-linked OTCase in the presence of sodium dodecyl sulfate showed that the enzyme is composed of three identical subunits . The molecular weight of the monomer was determined to be 39,000 . Steady-state kinetics indicate that the reaction mechanism is sequential . The limiting Michealis constants for carbamylphosphate and ornithine were determined to be 0.06 and 0.2 mM, respectively . The dissociation constant for carbamylphosphate was 0.02 mM . Product and dead-end inhibition patterns are consistent with an ordered Bi Bi mechanism, in which carbamylphosphate is the first substrate added and phosphate is the last product released . OTCase activity was inhibited by arginine, but relatively high concentrations were required for significant inhibition . The inhibition by arginine might be physiologically significant in the regulation of carbamlphosphate utilization; a single carbamylphosphate synthetase is responsible for the synthesis of carbamylphosphate for both arginine and pyrimidines in S . typhimurium and the inhibition by argine might serve to divert carbamlphosphate to the synthesis of pyrimidines when arginine is present at high concentrations . The crossreaction of OTCases from different microorganisms with purified antibodies raised against the homogeneous OTCase from S . typhimurium was investigated . The results of immunotitration and immunodiffusion experiments revealed a high degree of identity between the enzymes form S . typhimurium and Esherichia coli B and W . In these three cases, a single gen (argl) encodes OTCase . Wild-type E . coli K-12 and strain 3000 X 111, which carry two OTCase genes (argI, argF), also revealed similar cross-reactivity, supporting the hypothesis that argF is the product of a relatively recent duplication . The activity of OTCase from Bacillus subtilis was partially inhibited by antibodies against the enzyme from S . typhimurium, indicating unusual conservation of primary structure among widely different taxonomic groups . OTCase from Saccharomyces cerevisiae, whose molecular weight and primary structure are similar to those of the enzyme from S . typhimurium, was without detectable cross-reactivity. Eur J Biochem, 1977 Mar 1, 73(2), 521 - 7 Proton movements coupled to sugar transport via the galactose transport system in Salmonella typhimurium; Thienen GM et al.; We have studied proton movements associated with substrate transport via the galactose transport system in Salmonella typhimurium . The addition of galactose to lightly buffered suspensions of anaerobic, non-metabolizing cells of Salmonella typhimurium, specifically induced for the galactose transport system, causes an increase in extracellularpH as galactose and protons enter the cell together . Other substrates for this transport system, D-fucose, 2-deoxygalactose, glucose and 2-deoxyglucose similarly cause an influx of protons when transported . In contrast, transport via the other major transport system for galactose, the methylgalactoside transport system, is not coupled to H+ influx . Comparison of kinetic data obtained from pH measurements with data obtained from measurement of active transport of galactose via the galactose transport system suggests that the apparent Km of the galactose transport system for this sugar differs under energized and non-energized conditions . At pH 7.2 the permeant anion SCN- increases both the rate and extent of galactose-induced proton influx; at pH 6 the rate, but not the extent is increased by SCN-. Biochim Biophys Acta, 1977 Feb 14, 465(1), 152 - 64 Outer membrane of Salmonella typhimurium . Electron spin resonance studies; Nikaido H et al.; The supramolecular structure of the outer membrane of Salmonella typhimurium that produces an Rc-type lipopolysaccharide was studied by adding spin-labeled fatty acid probes to membranes as well as model bilayers . Lipopolysaccharide of this organism apparently formed a bilayer structure in 0.2 M NaCl/0.01 M MgCl2, and the electron spin resonance spectra suggested that the motion of the segments of hydrocarbon chains near the carboxyl end was quite restricted even at high temperature; this is presumably due to the anchoring of more than a dozen fatty acid residues to a single backbone structure . In the presence of Mg2+, we could produce lipoplysaccharide-phospholipid mixed bilayers contining up to 50% (by weight) lipoplysaccharide . Their spectra showed no sign of major heterogeneity, and the maximum hyperfine splitting values were considerably larger than in phospholipid-only liposomes; these results suggest that the two components are finely interspersed and that the mobility of phospholipid hydrocarbons is severely restricted by the hydrocarbon chains of lipopolysaccharide . In spite of the presence of lipoplysaccharide in an amount equal to or exceeding that of phospholipids, the outer membrane produced spectra remarkably similar to those of the inner membrane, which does not contain lipoplysaccharide, and there was little sign of immobilization by lipopolysaccharides . Signals corresponding to the pure lipoplysaccharide phase were not detected, either . These results suggest that the phospholipids and lipopolysaccharides are segregated into separate domains in the outer membrane, and the fatty acid probes enter almost exclusively into the phospholipid domains . This conclusion was fully corroborated by determining, through the exchange broadening of line width, the total area of the domains that accommodated the spin label probes. Biochemistry, 1977 Feb 8, 16(3), 381 - 6 Properties of the galactose binding protein of Salmonella typhimurium and Escherichia coli; Zukin RS et al.; The galactose binding protein implicated in transport and in chemotaxis has been purified to homogeneity from the shock fluids of Salmonella typhimurium and Escherichia coli . Both proteins are monomers of molecular weight 33 000 and exhibit cross-reactivity with antibody . The Salmonella galactose receptor showed binding of 1 mol of {14C}galactose or 1 mol of {14C}glucose at saturation . The dissociation constants were 0.38 and 0.17 muM, respectively . In light of the previously published report that the E . coli protein contains two binding sites with two different affinities, the binding characteristics of this protein were reexamined . Using highly purified radiolabeled substrate and homogeneous protein, a single binding site and single binding affinity were seen galactose (KD = 0.48 muM) or for glucose (KD = 0.21 muM) . The competition between glucose and galactose for the same site is intriguing in view of the competition between ribose and galactose at the receptor level. Biochim Biophys Acta, 1977 Feb 4, 464(3), 589 - 601 Outer membrane of Salmonella typhimurium . Identification of proteins exposed on cell surface; Kamio Y et al.; Proteins exposed on the outer surface of the outer membrane of Salmonella typhimurium were identified by reacting intact cells with a covalent labeling reagent . Since the outer membrane permitted the free diffusion of small hydrophilic molecules, we used a macromolecular reagent, CNBr-activated dextran, as the non-penetrating labeling agent . We also used a mutant producing a lipopolysaccharide with a very short (i.e . hexasaccharide) carbohydrate chain, in order to avoid steric hindrance by the carbohydrates on membrane surface . Results showed that out of the four "major" proteins of molecular weight around 35 000, three were exposed, and that at least six other proteins were also exposed on cell surface . Only two or three outer membrane proteins consistently did not react with the reagent in intact cells. Aust Vet J, 1977 Feb, 53(2), 82 - 7 Prevention of Salmonella typhimurium infection inpoultry by pretreatment of chickens and poults with intestinal extracts; Lloyd AB et al.; Day-old chickens or turkey poults when pretreated with an oral dose of intestinal fluid froma healthy adult bird, were considerably more resistant to the subsequent establishment of Salmonella typhimurium in their intestinal tract than were non-treated chickens or turkey poults . Caecal fluid was more effective as a pretreatment than were washings taken from other parts of the gastro-intestinal tract of a healthy adult bird . This increased resistance of pretreated chickens or poults is thought to result from the rapid establishment of a conventional indigenous microflora which inhabits establishment and growth by the invading enteric pathogen. Appl Environ Microbiol, 1977 Feb, 33(2), 434 - 44 Generalized indicator plate for genetic, metabolic, and taxonomic studies with microorganisms; Bochner BR et al.; We have developed an indicator plate that works well for diverse types of substrates and microorganisms . The plates are inexpensive and easy to prepare . The essential components are agar, buffer, growth-supporting nutrients, a test substrate, and 2,3,5-triphenyl tetrazolium chloride (TTC) . Using various strains of Salmonella typhimurium and Escherichia coli, we have studied and defined the contribution of each component to the satisfactory function of the plate . Colonies capable of catabolizing the test substrate reduce TTC and produce a deep red formazan, whereas colonies failing to catabolize the substrate remain uncoloured . Those with intermediate rates of catabolism differ in rate and/or extent of color formation . In all cases the color is stable because TTC reduction is essentially irreversible . Since the mode of action of these plates is fairly well understood, alternative formulations can be devised to meet specific needs . The general applicability of this TTC indicator system makes it an extremely useful tool in microbial genetics, metabolism, and taxonomy. Proc Natl Acad Sci U S A, 1977 Feb, 74(2), 533 - 7 Identification of a protein methyltransferase as the cheR gene product in the bacterial sensing system; Springer WR et al.; Methylation of membrane-bound proteins with apparent molecular weights around 65,000 does not occur in mutants of the generally nonchemotactic cheR class of Salmonella typhimurium . This was shown to be due to the lack of a protein methyltransferase in these mutants by means of an in vitro assay using soluble proteins, membranes, and S-adenosylmethionine as the methyl donor . The methylase from the wild type was purified, characterized, and shown to be of molecular weight 38,000 . It is specific for proteins in S . typhimurium and Escherichia coli membranes . The methylase is not required for tumbling but appears to be essential for maintaining the appropriate rate constants and levels of the regulator of the chemotactic response. Infect Immun, 1977 Feb, 15(2), 491 - 9 Comparison of the virulence of O:9,12 and O:4,5,12 Salmonella typhimurium his+ transductants for mice; Lyman MB et al.; The purpose of these experiments was to determine whether qualitative differences in the O repeat unit of the lipopolysaccharide of pathogenic Salmonella species affected virulence for mice . O:4,5,12 and O:9,12 sister his+ transductants were derived from a virulent Salmonella typhimurium . Fermentation markers were introduced by transduction to differentiate these strains, and the strains were used as mixed challenge to CF1 and C57B1/6J mice . Liver and spleen cultures of the mice of various intervals after challenge indicated that the O:4,5,12 member of the nearly isogenic pair regularly multiplied to a greater extent than the O:9,12 after intraperitoneal challenge for both strains of mice . After oral challenge, there was little difference in the amount of multiplication of the O:4,5,12 and O:9,12 strains in CF1 mice, but the O:4,5,12 was the predominant strain recovered in 8 of 10 instances in the C57B1/6J mice. Zentralbl Bakteriol {Orig A}, 1977 Feb, 237(1), 54 - 64 {Epidemiologic relationship of infections with Salmonella typhimurium in Switzerland studied by phage typing (author's transl)}; Pagon S et al.; In the area, controlled by the Institute of Microbiology of St . Gall, 262 S . typhi murium strains could be isolated during 1973 . By means of phage typing, according to GUINEE, 20 different phage types as well as 6 additional atypically reacting strains, with characteristic atypical pattern, were recognized . The phage type 650 was most frequently encountered (37.0%) folowed by types 61 (20.2%) and 505 (10.3%) . An intensive change in phage types was noted among 114 cases, observed over 7 months, in the region of Wil SG . In the beginning, 5 different phage types were determined, but in the following 2 months, they were replaced by the type 650, and, finally, by the type 61 . Phage typing enabled the understanding of epidemiologic relationship of two outbreaks occurring in Kirchberg (type 650) and Butschwil (type 61) by consumption of infected slaughtered beef . Also, an outbreak of the infection in Wil, transmitted by an infected butcher, could be cleared . Testing of the resistance against tetracycline, chloramphenicol, ampicillin and trimethoprim-sulphamethoxazol showed that 80.1% of the strains were sensitive and 18.3% were resistent against tetracycline; some phage types were sensitive (2, 3, 4, 61 etc.), predominantly sensitive (650) or resistent (330, 450, 504, 505 ARS-12) . Four strains were resistent against one or more chemotherapeutic agents used. Zentralbl Bakteriol {Orig A}, 1977 Feb, 237(1), 44 - 53 {Drug resistance of phage types of Salmonella typhimurium (author's transl)}; Balzer K; Antimicrobial susceptibility testing (disk diffusion test) and phage typing (method according to Anderson, performed by Prof . Brandis, Bonn) of 703 strains of Salmonella typhimurium from humans, isolated in Essen and surrounding during 1972 to 1975, was performed to dertermine whether characteristic patterns of drug resistance were associated with a single phage type or not . The most frequently isolated phage types are phage type 17 (12.2%), 12 (10.1%), 49 (8.1%), 15a (5.7%), 2 (3,3%) and the untypable phage type (46.7%) . Resistance to tetracycline (45%) was most common, followed by resistance to sulfanilamide (19%), ampicillin (9%), and chloramphenicol (7%) . Resistance to other antimicrobial agents (trimethoprim/sulfamethoxazol, gentamicin, colistin) was quite rare . Antibiograms of different phage types were found to be different, not only as far as the ratio of sensitive to resistant strains is concerned, but also for the ratio single-resistant to multiple-resistant strains . These differences were found to be statistically significant (chi-square-test, table 2) . Comparison of antimicrobial resistance to tetracycline showed, that the portion of resistant strains was about 70% for the untypable phage types, 40% for phage type 17 and 7% for phage type 12 . Among isolates of the phage type 49 multiple resistance was most common . The combination of resistance determinants is specified in figure 3 . A possible interrelation between resistance pattern and the presence of R-plasmids in isolated strains is discussed. Z Orthop Ihre Grenzgeb, 1977 Feb, 115(1), 116 - 8 {Spondylitis caused by Salmonella typhimurium (author's transl)}; Winkelmann W et al.; Described is a case of spondylitis caused by Salmonella typhimurium . According to literature osteomyelitis and spondylitis are rare as local manifestation of a salmonella infection . Spondylitis caused by Salmonella typhimurium, the most common species, is almost unknown . The problems in diagnosis and therapy are discussed. Mutat Res, 1977 Feb 1, 46(1), 11 - 8 Comparative mutagenicity of ICR-191 to S . typhimurium and diploid human lymphoblasts; Deluca JG et al.; Concentration-dependent mutagenicity of ICR-191 has been measured in Salmonella typhimurium strain TA98 and in a diploid human cell line . In both cell systems, approximately equigenerational exposure produced mutation linearly related to concentration in the lower range of ICR-191 concentrations tested . Saturation behavior was observed in the human cell assay but not in the bacterial assay . However, a 25-fold greater concentration of ICR-191 was required to induce a significant rise in the mutant fraction in the S . typhimurium assay than in the human cell assay . These differences may be linked to the differences in the biochemical events required for mutation or in the time of exposure to ICR-191. J Bacteriol, 1977 Feb, 129(2), 740 - 9 Influence of methionine biosynthesis on serine transhydroxymethylase regulation in Salmonella typhimurium LT2; Stauffer GV et al.; The enzyme serine transhydroxymethylase (EC 2.1.2.1; L-serine:tetrahydrofolate-5,10-hydroxymethyltransferase) is responsible both for the synthesis of glycine from serine and production of the 5,10-methylenetetrahydrofolate necessary as a methyl donor for methionine synthesis . Two mutants selected for alteration in serine transhydroxymethylase regulation also have phenotypes characteristic of metK (methionine regulatory) mutants, including ethionine, norleucine, and alpha-methylmethionine resistance and reduced levels of S-adenosylmethionine synthetase (EC 2.5.1.6; adenosine 5'-triphosphate:L-methionine S-adenosyltransferase) activity . Because this suggested the existence of a common regulatory component, the regulation of serine transhydroxymethylase was examined in other methionine regulatory mutants (metK and metJ mutants) . Normally, serine transhydroxymethylase levels are repressed three- to sixfold in cells grown in the presence of serine, glycine, methionine, adenine, guanine, and thymine . This does not occur in metK and metJ mutants; thus, these mutations do affect the regulation of both serine transhydroxymethylase and the methionine biosynthetic enzymes . Lesions in the metK gene have been reported to reduce S-adenosylmethionine synthetase levels . To determine whether the metK gene actually encodes for S-adenosylmethionine synthetase, a mutant was characterized in which this enzyme has a 26-fold increased apparent Km for methionine . This mutation causes a phenotype associated with metK mutants and is cotransducible with the serA locus at the same frequency as metK lesions . Thus, the affect of metK mutations on the regulation of glycine and methionine synthesis in Salmonella typhimurium appears to be due to either an altered S-adenosylmethionine synthetase or altered S-adenosylmethionine pools. J Bacteriol, 1977 Feb, 129(2), 589 - 98 Repression and inhibition of transport systems for branched-chain amino acids in Salmonella typhimurium; Kiritani K et al.; Kinetics of the transport systems common for entry of L-isoleucine, L-leucine, and L-valine in Salmonella typhimurium LT2 have been analyzed as a function of substrateconcentration in the range of 0.5 to 45 muM . The systems of transport mutants, KA203 (ilvT3) and KA204 (ilvT4), are composed of two components; apparent Km values for uptake of isoleucine, leucine, and valine by the low Km component are 2 muM, 2 to 3 muM, and 1 muM, respectively, and by the high Km component 30 muM, 20 to 40 muM, and 0.1 mM, respectively . The transport system(s) of the wild type has not been separated into components but rather displays single Km values of 9 muM for isoleucine, 10 muM for leucine, and 30 muM for valine . The transport activity of the wild type was repressed by L-leucine, alpha ketoisocaproate, glycyl-L-isoleucine, glycyl-L-leucine, and glycyl-L-methionine . That for the transport mutants was repressed by L-alanine, L-isoleucine, L-methionine, L-valine, alpha-ketoisovalerate, alpha-keto-beta-methylvalerate, glycyl-L-alanine, glycyl-L-threonine, and glycyl-L-valine, in addition to the compounds described above . Repression of the mutant transport systems resulted in disappearance of the low Km component for valine uptake, together with a decrease in Vmax of the high Km component; the kinetic analysis with isoleucine and leucine as substrates was not possible because of poor uptake . The maximum reduction of the transport activity for isoleucine was obtained after growing cells for two to three generations in a medium supplemented with repressor, and for the depression, protein synthesis was essential after removal of the repressor . The transport activity for labeled isoleucine in the transport mutant and wild-type strains was inhibited by unlabeled L-alanine, L-cysteine, L-isoleucine, L-leucine, L-methionine, L-threonine, and L-valine . D-Amino acids neither repressed nor inhibited the transport activity of cells for entry of isoleucine. J Virol, 1977 Feb, 21(2), 825 - 8 Patterns of transcription in bacteriophage P22-infected Salmonella typhimurium; Pipas JM et al.; Two peaks of RNA synthesis (early and late) are directed by bacteriophage P22 in lytic infections of Salmonella typhimurium . Late RNA synthesis is not seen in P22 23- infections; neither early nor late RNA synthesis occurs in P22 24- infections . Genes 23 and 24 of P22 appear to be analogous to genes Q and N of lambda, respectively. J Natl Cancer Inst, 1977 Feb, 58(2), 449 - 51 Airborne mutagens bioassayed in Salmonella typhimurium; Talcott R et al.; Particulate airborne pollutants, collected in Buffalo, New York, and Berkeley, California, were asayed for mutagenic activity in the Ames Salmonella typhimurium test system . Mutagens requiring liver enzymes for activation, as well as direct acting mutagens, were readily detected in the Buffalo sample . By contrast, only direct acting mutagens were detected in the Berkeley sample. J Natl Cancer Inst, 1977 Feb, 58(2), 393 - 4 Mutagenicity of five cyclic N-nitrosamines: assay with Salmonella typhimurium; Stoltz DR et al.; The mutagenicity of five cyclic N-nitrosamines was studied with the use of Salmonella typhimurium TA1535 in vitro with and without microsomal activation . The carcinogens nitrosopiperidine and nitrosopyrrolidine required metabolic activation before manifesting mutagenic activity . Nitrosoproline and nitrosohydroxyproline, noncarcinogens, were not mutagenic . Nitroso-3-pyrrolidinol was mutagenic in the absence of microsomes, thereby suggesting a role of hydroxylation in the metabolic activation of nitrosopyrrolidine to an ultimate carcinogenic species. J Gen Microbiol, 1977 Feb, 98(2), 379 - 85 Expression of Klebsiella nif and his genes in Salmonella typhimurium; Postgate JR et al.; Derivatives of Salmonella typhimurium carrying F prime or P prime plasmids with Klebsiella nif and his genes had specific nitrogenase activities similar to Klebsiella in selective conditions, even to showing "hyperinduction" under argon . No evidence was obtained for catabolite repression of normal nif expression but dibutyl cyclic AMP often augmented "hyperinduction" . In non-selective conditions the Klebsiella his nif determinants were rapidly lost from the plasmids; the low levels of nif expression and temperature-sensitive his expression previously reported were probably due to ready loss of his nif in the test conditions used. J Bacteriol, 1977 Feb, 129(2), 630 - 9 Galactose transport in Salmonella typhimurium; Postma PW; We have studied the various systems by which galactose can be transported in Salmonella typhimurium, in particular the specific galactose permease (GP) . Mutants that contain GP as the sole galactose transport system have been isolated, and starting from these mutants we have been able to select point mutants that lack GP . The galP mutation maps close to another mutation, which results in the constitutive synthesis of GP, but is not linked to galR . Growth of wild-type strains on glaactose induces GP but not the beta-methylgalactoside permease (MGP) . Strains lacking GP are able to grow slowly on galactose, and MGP is induced; however, D-fucose is a much better inducer of MGP . Induction of GP or MGP is not prevented by a pts mutation, although this mutation changes the apparent Km of MGP for galactose . pts mutations have no effect on GP . GP has a rather broad specificity: galactose, glucose, mannose, fucose, 2-deoxygalactose, and 2-deoxyglucose are substrates, but only galactose and fucose can induce this transport system. J Gen Microbiol, 1977 Feb, 98(2), 369 - 77 Lack of a regulatory function for glutamine synthetase protein in the synthesis of glutamate dehydrogenase and nitrite reductase in Escherichia coli K12; Newman BM et al.; Synthesis of glutamine synthetase (GS) in anaerobic batch cultures of Escherichia coli was repressed when excess NH4+ was available, but derepressed during growth with a poor nitrogen source . In wild-type bacteria there was only a weak inverse correlation between the activities of GS and gl