Am J Clin Nutr, 1980 Nov, 33(11 Suppl), 2491 - 501 Interaction between Salmonella bacteria and mammalian nonprofessional phagocytes; Kilhstrom E; A series of lipopolysaccharide mutants of Salmonella typhimurium and Salmonella minnesota were studied regarding their interaction with HeLa cells . The bacteria differed in physicochemical surface properties, with respect to charge and propensity to hydrophobic interaction . Mutants with propensity to hydrophobic interaction and/or negative charge attached to and were internalized into HeLa cells to a greater extent than bacteria lacking such surface properties . Heat-killed and ultraviolet-killed bacteria did not attach to HeLa cells . Metabolic and ultrastructural studies showed that Salmonella bacteria were internalized into HeLa cells by an endocytic process . Hyperimmune IgG and other proteins may inhibit this ingestion. J Pharmacobiodyn, 1980 Nov, 3(11), 557 - 61 Mutagenicity of N-acylglycinohydroxamic acids and related compounds; Munakata K et al.; The mutagenic activity of twenty-nine new N-acylglycinohydroxamic acids and related compounds was tested on Bacillus subtilis (Rec(+), Rec(-)) and Salmonella typhimurium (TA 98, TA 100) . All the N-(substituted-benzoyl)glycinohydroxamic acids, except 3-acetylaminobenzoyl-derivative, were shown to be mutagenic to both test bacteria, whereas most of the N-aliphatic acylglycinohydroxamic acids were found to be non-mutagenic . In the present study, we discussed out observations focussing on the structure-activity correlation between their chemical structures and mutagenic activities. Parazitologiia, 1980 Nov-Dec, 14(6), 477 - 81 {Characteristics of microbial multiplication in parenterally infected Xenopsylla cheopis (Siphonaptera) fleas}; Vashchenok VS; Being inoculated parenterally various microbes cause the fleas X . cheopis a stable infection which, as a rule, is preserved in experimental insects to the end of life . Reproducing intensively Listeria monocytogenes and Salmonella typhimurium caused the death of all ectoparasites in 3 to 5 days . The increase in abundance of Escherichia coli, Yersinia pseudotuberculosis, Y . enterocolitica and vaccine strains of Y . pestis "EV" and Francisella tularensis went on gradually and infected fleas lived up to 15--20 and more days. J Bacteriol, 1980 Nov, 144(2), 656 - 60 Mutagenesis by neocarzinostatin in Escherichia coli and Salmonella typhimurium: requirement for umuC+ or plasmid pKM101; Eisenstadt E et al.; Neocarzinostatin, a protein with antibiotic activity, is a bacterial mutagen . We have investigated the mutagenicity of neocarzinostatin towards Salmonella typhimurium and discovered that, unlike the situation in Escherichia coli, neocarzinostatin will revert base pair substitution mutations (missense or nonsense) . However, when the R46 factor derivative, plasmid pKM101, was introduced, the mutagenicity of neocarzinostatin towards base pair substitution-carrying mutants of S . typhimurium was readily detected . Neocarzinostatin had only modest activity in reverting a frameshift mutation in S . typhimurium, but that activity, too, required the presence of pKM101 . Mutant pKM101 plasmids which no longer enhanced mutagenesis also lost their ability to promote neocarzinostatin-induced mutations . Finally, the umuC36 mutation, which renders E . coli nonmutable by ultraviolet light, also rendered the bacteria nonmutable by neocarzinostatin . The effect of the umuC36 mutation was suppressed by plasmid pKM101. J Bacteriol, 1980 Nov, 144(2), 848 - 51 Bacteriophage P1 as a vehicle for Mu mutagenesis of Salmonella typhimurium; Rosenfeld SA et al.; We developed a procedure using bacteriophage P1 as a vector for transferring Mu phage deoxyribonucleic acid into Salmonella typhimurium . Mu phage transferred in this manner yielded lysogenic auxotrophs, and we demonstrated that specific deletions and lac gene fusions can be selected. J Gen Microbiol, 1980 Nov, 121(1), 27 - 38 Repression and derepression of the enzymes of the pyrimidine biosynthetic pathway in Salmonella typhimurium; Smith JM et al.; Activities of five enzymes of the pyrimidine biosynthetic pathway and one enzyme involved in arginine synthesis were measured during batch culture of Salmonella typhimurium . Aspartate carbamoyltransferase, dihydroorotase, and the arginine pathway enzyme, ornithine carbamoyltransferase, remained constant during the growth cycle but showed a sharp decrease in activity after entering the stationary phase . Dihydroorotate dehydrogenase, orotate phosphoribosyltransferase and orotidine-5'-monophosphate (OMP) decarboxylase showed peaks of activity corresponding to the mid-point of the exponential phase of growth while remaining comparatively stable in the stationary phase . Derepression studies carried out by starving individual pyrimidine (Pyr-) deletion mutants for uracil showed that the extent of derepression obtained for aspartate carbamoyltransferase, dihydroorotase and dihydroorotate dehydrogenase depended on the location of the pyr gene mutation . Orotate phosphoribosyltransferase and OMP decarboxylase derepression levels were independent of the location of the pyr mutation . Aspartate carbamoyltransferase showed the greatest degree of derepression of the six enzymes studied, with pyrA strains (blocked in the first step of the pathway) showing about twice as much derepression as pyrF strains (blocked in the sixth step of the pathway) . A study of the kinetics of repression on derepressed levels of the pyrimidine enzymes produced data that were compatible with dilution of specific activity by cell division when repressive amounts of uracil were added to the derepression medium. Gene, 1980 Nov, 11(3-4), 227 - 37 Characterization of a HindIII-generated DNA fragment carrying the glutamine synthetase gene of Salmonella typhimurium; Koduri RK et al.; The glnA gene, encoding glutamine synthetase in Salmonella typhimurium, has been cloned into the plasmid pBR322 . One hybrid plasmid, pJB1, containing an 8.5 kb insert generated by a HindIII digest, was analyzed using eleven different restriction enzymes . Evidence that the region controlling glutamine synthetase expression remained on the insert was obtained by showing that the regulation is normal in cells carrying plasmids with the insert in the original and reversed orientation . Several new plasmids derived from pJB1 following SalI and EcoRI digestions were examined for their ability to complement a glnA202 mutation in order to locate the DNA segment needed for glutamine synthetase expression . The results show that cells containing plasmid pJB8, which has a 21 kb deletion, produce and regulate glutamine synthetase normally, whereas cells with a plasmid (pJB11) similar to pJB8, but lacking a 0.25 kb EcoRI fragment, do not exhibit glutamine synthetase activity . The analysis of proteins produced in minicells containing pJB8 and pJB11 show that they both produce a protein that migrates with the glutamine synthetase subunit . Because pJB11 makes an inactive protein of similar size to the glutamine synthetase subunit, the 0.25 kb deletion may encode only the C-terminus of this protein . Consistent with this finding is the presence of a strong RNA polymerase-binding site on pJB8 to the right of the 0.25 kb EcoRI that could correspond to a promoter near the N-terminus of the glnA gene. J Bacteriol, 1980 Nov, 144(2), 800 - 5 Characterization of type 1 pili of Salmonella typhimurium LT2; Korhonen TK et al.; Type 1 pili from Salmonella typhimurium LT2 were purified and characterized . The pilus filaments were 6 nm in diameter and over 1 microns long . Estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the molecular weight of the pilin was 21,000 . The isoelectric point of the filament was 4.1 . Hydrophobic amino acids comprised 40.3% of the total amino acids of the pilin, which contained more proline, serine, and lysine than reported for the type 1 pilin of Escherichia coli . Purified pili agglutinated both horse and chicken erythrocytes and yeast cells but not bovine, sheep, or human erythrocytes . Horse erythrocyte agglutination was inhibited at lower concentrations by alpha-methyl-D-mannoside than by yeast mannane and D-fructose . Agglutination was not affected by D-galactose or sucrose . Results of the present study confirm the role of type 1 pili as Salmonella hemagglutinins and show chemical differences between the type 1 pili of S . typhimurium and E . coli. Biochemistry, 1980 Oct 28, 19(22), 5087 - 92 Estimation of apurinic/apyrimidinic sites and phosphotriesters in deoxyribonucleic acid treated with electrophilic carcinogens and mutagens; Drinkwater NR et al.; The number of apurinic/apyrimidinic (AP) sites in supercoiled SV40 deoxyribonucleic acid (DNA) after treatment with several electrophilic mutagens was quantitated by electrophoretic analysis of the DNA after cleavage of the phosphodiester bonds adjacent to AP sites by a specific endonuclease . The compounds studied, in order of increasing yields of AP sites obtained on incubation with the DNA for 5 h at 37 degrees C, were dimethylcarbamoyl chloride, ethyl methanesulfonate, N-ethyl-N-nitrosourea, 2-(N-acetoxyacetylamino)fluorene, beta-propiolactone, N-methyl-N-nitrosourea, methyl methanesulfonate, 1'-acetoxyestragole, 4-(N-acetoxyacetylamino)stilbene, (+/-)-7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo{a}pyrene, N-(benzoyloxy)-N-methyl-4-aminoazobenzene, and 1-pyrenyloxirane . After a 5-h incubation at 37 degrees C and extraction of unreacted compound, further incubation at 70 degrees C generally increased the yield of AP sites; an exception was N-(benzoyloxy)-N-methyl-4-aminoazobenzene-reacted DNA . Except for DNA treated with N-ethyl-N-nitrosourea and N-methyl-N-nitrosourea, which are known to bind to a significant extent to DNA phosphates, the number of alkali-labile lesions in the treated DNA was similar to the number of AP sites . For the compounds studied there was no direct correlation between the number of AP sites produced and missense mutagenic activity, as measured in Salmonella typhimurium strain TA100. Nature, 1980 Oct 2, 287(5781), 440 - 2 Control of natural resistance to Salmonella typhimurium and Leishmania donovani in mice by closely linked but distinct genetic loci; O'Brien AD et al.; Inbred strains of mice vary in their sensitivity to infection with both Salmonella typhimurium and Leishmania donovani . In both cases, this differential susceptibility is genetically controlled . Resistance to the intracellular parasite L . donovani is determined by a single locus on chromosome 1, designated Lsh (ref . 4) . The primary regulator of resistance to S . typhimurium is a single, dominant autosomal gene, named Ity (for immunity to typhimurium), and it has also been recently mapped to chromosome 1 (ref . 6) . In addition, two other genetic loci regulate resistance to S . typhimurium in mice . These genes, Lpsd and xid, are mutant alleles that render C3H/HeJ and CBA/N mice, respectively, salmonella susceptible . Both Bradley and his colleagues, and Plant and Glynn, noted similar patterns of resistance or susceptibility of inbred strains of mice to L . donovani and S . typhimurium, and therefore suggested that Lsh and Ity might be the same gene . Mapping of both genes to the same region of chromosome 1 supported this hypothesis but no linkage studies have been used to test it . Since recombinant inbred (RI) mouse strains are, in effect, permanent segregant populations, they are ideal for determing linkage between resistance genes to two different pathogens . Therefore, we determined the S . typhimurium susceptibility of five sets of RI mouse strains that had been previously typed for Lsh and conclude that Lsh and Ity are closely linked but distinct genetic loci. Mutat Res, 1980 Oct, 74(5), 341 - 6 Mutagenic activation of dibromomethane and diiodomethane by mammalian microsomes and glutathione S-transferases; van Bladeren PJ et al.; The influence of mammalian metabolizing enzymes on the mutagenic activity of dibromomethane and diiodomethane was investigated by using Salmonella typhimurium strain TA100 as indicator . The 2 compounds are known to be metabolized via an oxidative pathway catalysed by microsomal enzymes as well as through direct enzymatic conjugation with glutathione; both pathways possibly give rise to reactive electrophilic intermediates . In mutagenicity plate assays with pre-incubation, dibromo- and diiodo-methane were directly mutagenic towards strain TA100; their mutagenic activity was enhanced upon incubation either with rat-liver microsomes or with the cytosol fraction of the same organ, containing the glutathione S-transferases . These data can be taken as an indication that both microsomal oxidation and conjugation to glutathione are indeed responsible for the mammalian mutagenic activation of dihalomethanes. Can J Biochem, 1980 Oct, 58(10), 797 - 803 Citrate transport in Salmonella typhimurium: studies with 2-fluoro-L-erythro-citrate as a substrate; Ashton DM et al.; The citrate analogue, 2-fluoro-L-erythro-{3,4,5,6-(14)C}citrate was synthesized as a probe for the citrate transport system of Salmonella typhimurium . This analogue was actively transported by an inducible energy-dependent transport system with high affinity for fluorocitrate (Km = 3.3 microM), and this transport system was inhibited competitively by citrate and isocitrate . Fluorocitrate was shown to be a competitive inhibitor of the citrate-binding protein (C protein) of this organism (Ki = 4-5 microM) . Analogue resistant mutants were simultaneously defective in fluorocitrate transport as well as the C protein and the affected allele, tctC, was located at 59 units on the S . typhimurium chromosome map . These tctC mutants were shown to be specifically defective in K+-dependent fluorocitrate transport but still retained another system capable of transporting fluorocitrate in the presence of both Na+ and K+. J Hyg (Lond), 1980 Oct, 85(2), 293 - 300 Plasmid studies of Salmonella typhimurium phage type 179 resistant to ampicillin, tetracycline, sulphonamides and trimethoprim; Anderson DM; Sixteen strains of Salmonella typhimurium phage type 179 were referred to the National Health Institute, Wellington, New Zealand, from 1977 to 1979 . This phage type had not been observed here before 1977 . All strains were resistant to ampicillin, several were also resistant to tetracycline, and several were resistant to ampicillin, tetracycline, sulphafurazole and trimethoprim . All resistances could be transferred to Escherichia coli K 12 . Plasmids from these strains and their transconjugants were characterized by agarose gel electrophoresis . It appears that resistance to sulphafurazole and trimethoprim is carried on a plasmid with a molecular weight of 5 . 2 Mdal and that resistance to ampicillin and tetracycline is carried on a plasmid with a molecular weight of approximately 60 Mdal. J Dairy Res, 1980 Oct, 47(3), 305 - 11 Characterization and response to mitogens of mammary lymphocytes from the bovine dry-period secretion; Concha C et al.; From bovine mammary secretion during the dry period, the total number of cells was between 1.2 and 5.9 X 10(6)/ml . A mean of 35% of these cells were classified as lymphocytes and approximately 85% of them could be isolated by the Ficoll-isopac method . Centrifugation separated 6% of the cells into the fat; 5% of them were lymphocytes . About 47% of the lymphocytes bound Helix pomatia agglutinin, a T-cells marker, while the proportion of Ig-bearing cells was approximately 28% . The mammary lymphocytes were stimulated by the lectins phytohaemagglutinin, pokeweed mitogen, concanavalin A and by lipopolysaccharide from Salmonella typhimurium . The stimulation indices of mammary lymphocytes were generally lower than those for peripheral blood lymphocytes from the same animals . The background values, i.e . counts/min of lymphocytes incubated without mitogen, were often higher for lymphocytes isolated from mammary secretion than from blood. Can J Comp Med, 1980 Oct, 44(4), 374 - 81 Changes in the Salmonella status of broiler chickens subjected to simulated shipping conditions; Rigby CE et al.; Market-age broiler chickens from flocks infected with Salmonella typhimurium were killed after being placed in crates and subjected to simulated shipping conditions for five, 19 or 24 hours . The cloacal feces, ceca and exteriors of the birds were cultured for salmonellae to identify shedders, cecal carriers and external carriers respectively, and the results compared with those obtained from pen-mates killed at the time the tested birds were put into the crates . Carriage of S . typhimurium was significantly higher among birds placed in clean crates than among the uncrated controls, mainly due to an increase in cecal carriers (from 23.5% to 61.5%) . This increase was not related to the time spent in the crate . Twenty-four chickens were placed in crates contaminated with Salmonella alachua and all 24 became carriers of this organism: 22 (91.5%) of these were cecal carriers and 18 (75%) were shedders . This contamination also spread to 15/24 chickens placed in clean crates and "shipped" in the same truck: six of these became cecal carriers and seven were shedders . These results indicated that chickens in shipping crates which are exposed to salmonellae under transport conditions may readily become infected and begin to shed salmonellae within 24 hours. J Infect Dis, 1980 Oct, 142(4), 485 - 91 Increase in antibiotic resistance among isolates of Salmonella in the United States, 1967-1975; Ryder RW et al.; To study temporal changes in the antibiotic resistance of Salmonella in the United States, a study design similar to that of a 1967 study was used to determine the antibiotic sensitivity of 754 human nontyphoid Salmonella isolates sent to the Center for Disease Control, Atlanta, Georgia, in 1975 . The frequency of resistance to one or more of the same nine antibiotics used in both studies increased significantly during the eight years in Salmonella typhimurium (40%-59%; P = 0.004), other serotypes (14%-23%; P = 0.001), and all serotypes combined (21%-31%; P < 0.001) . The increase in frequency of resistance was significant for streptomycin (P = 0.022), sulfonamides (P < 0.001), ampicillin (P < 0.001), and kanamycin (P < 0.001) . No chloramphenicol-resistant isolates were found in the 1967 study, whereas six isolates (0.8%) were resistant in 1975 . The frequency of strains resistant to six or more antibiotics increased greatly (0.8%-5.0%; P < 0.001) . These data document a continuing increase in antimicrobial resistance among Salmonella isolates. Cancer Res, 1980 Oct, 40(10), 3463 - 7 Mutagenic activities of oxidized derivatives of N-nitrosodipropylamine in the liver cell-mediated and Salmonella typhimurium assays; Langenbach R et al.; The mutagenic activity of N-nitrosobis(2-oxopropyl)amine (BOP), N-nitroso(2-hydroxypropyl) (2-oxopropyl)amine (HPOP), N-nitrosobis(2-hydroxypropyl)amine (BHP), N-nitrosomethyl-2-oxopropylamine (MOP), and N-nitrosomethyl-2-hydroxypropylamine (MHP) was examined in the Ames liquid incubation assay, using hamster liver homogenate for metabolic activation, and in the hamster liver cell-mediated V79 cell assay . At similar concentrations, the cell-mediated assay showed a greater mutagenic response over background to these nitrosamines than did the bacterial assay . Also, the relative mutagenic potency in the cell-mediated assay (MOP > MHP > BOP > HPOP > BHP) correlated better than that in the Ames assay (HPOP > MHP greater than or equal to BOP = BHP = MOP) with overall carcinogenic potency in the hamster (MOP > BOP > HPOP > BHP) . The liver cell-mediated assay may be an important adjunct to the battery of short-term tests for carcinogenicity prescreening. Mutat Res, 1980 Oct, 79(2), 91 - 105 Mutagenicity of antibiotics in microbial assays . Problems of evaluation; Mitchell I deG et al.; 5 antibiotics, 4 of which inhibit protein synthesis in different ways, and 1 of which inhibits bacterial cell-wall synthesis, were tested in a battery of microbial assays for possible genetic effects . All the antibiotics, chloramphenicol, tetracycline, gentamicin, oleandomycin and phosphonomycin induced forward mutation to L-azetidine-2-carboxylic acid resistance in Escherichia coli WP2 . This response was closely correlated with the toxic effects and was inferred to be deletion mutation . In addition, chloramphenicol was weakly active in reversion of the frame-shift mutation in Salmonella typhimurium TA98, gentamicin caused petite induction in S . cerevisiae at pH 4.4--4.7 and tetracycline gave a significant reponse with gene conversion and petite induction also in S . cerevisiae but at pH 7.2 . The results, particularly those with E . coli, cast doubts on the validity of testing specifically designed antibacterial agents in bacteria, and raise serious problems in the evaluation of such data in terms to human populations. Mutat Res, 1980 Oct, 79(2), 107 - 14 Detection of mutagenicity of procarbazine by the host-mediated assay with polychlorinated biphenyl (aroclor 1254) as enzyme inducer; Moriya M et al.; Procarbazine {N-isoppropyl-alpha-(2-methylhydrazino)-p-toluamide} was tested for mutagenicity with Salmonella typhimurium G46 in the host-mediated assay by using male BALB/c mice pretreated orally with polychlorinated biphenyl (PCB, Aroclor 1254) . Procarbazine was weakly mutagenic without PCB pretreatment, but the pretreatment greatly enhanced the mutagenicity of this compound . The administration of 500 mg PCB/kg 1 day before procarbazine dosage was suitable for the detection of the mutagenicity . Among PCB, 3-methylcholanthrene (3-MC) and phenobarbital sodium (PB), the former 2 inducers showed much stronger enhancing effects than PB . The pretreatment with 3-MC in combination with PB did not cause further enhancement compared with 3-MC alone. J Bacteriol, 1980 Oct, 144(1), 337 - 45 Possible regulation of the Salmonella typhimurium histidine operon by adenosine triphosphate phosphoribosyltransferase: large metabolic effects; Goitein RK et al.; An effort to find growth conditions leading to conditional regulation of the histidine operon of Salmonella typhimurium by the allosteric first enzyme of the pathway, adenosine triphosphate phosphoribosyltransferase (EC 2.4.2.17), is reported . A strain deleting the enzyme, TR3343, behaved simply and predictably under all growth conditions, whereas histidine auxotrophs containing active enzyme behaved in complicated ways dependent upon the location of the histidine pathway lesion . hisE strains derepressed the operon only one-half as much as TR3343 when grown on limiting histidine and a poor carbon source, but they also grew more slowly, probably as a result of high N1-(5-phospho-beta-D-ribosyl)-adenosine triphosphate levels in the cell . hisC strains exhibited oscillatory growth behavior and oscillatory histidine operon expression when grown on intermediate concentrations of the histidine precursor histidinol . This behavior probably was caused by synergistic in-phase variations in the histidine, purine nucleotide, and ppGpp pools of the cell . All of the growth and histidine operon expression effects associated with the presence of adenosine triphosphate phosphoribosyltransferase could be assigned to metabolic perturbation of the cell caused by unregulated enzymatic activity. J Bacteriol, 1980 Oct, 144(1), 300 - 5 UGA suppressor that maps within a cluster of ribosomal protein genes; Johnston HM et al.; A suppressor of UGA mutations (supU) maps near or within a cluster of ribosomal protein genes at 72 min on the Salmonella typhimurium genetic map . The suppressor is relatively inefficient, and its activity is abolished by rpsL (formerly strA) mutations . The suppressor is dominant to a wild-type supU allele . The map position of this suppressor suggests that it may owe its activity to an alteration of ribosome structure. J Bacteriol, 1980 Oct, 144(1), 192 - 9 Cation coupling to melibiose transport in Salmonella typhimurium; Niiya S et al.; Melibiose transport in Salmonella typhimurium was investigated . Radioactive melibiose was prepared and the melibiose transport system was characterized . Na+ and Li+ stimulated transport of melibiose by lowering the Km value without affecting the Vmax value; Km values were 0.50 mM in the absence of Na+ or Li+ and 0.12 mM in the presence of 10 mM NaCl or 10 mM LiCl . The Vmax value was 140 nmol/min per mg of protein . Melibiose was a much more effective substrate than methyl-beta-thiogalactoside . An Na+-melibiose cotransport mechanism was suggested by three types of experiments . First, the influx of Na+ induced by melibiose influx was observed with melibiose-induced cells . Second, the efflux of H+ induced by melibiose influx was observed only in the presence of Na+ or Li+, demonstrating the absence of H+-melibiose cotransport . Third, either an artificially imposed Na+ gradient or membrane potential could drive melibiose uptake in cells . Formation of an Na+ gradient in S . typhimurium was shown to be coupled to H+ by three methods . First, uncoupler-sensitive extrusion of Na+ was energized by respiration or glycolysis . Second, efflux of H+ induced by Na+ influx was detected . Third, a change in the pH gradient was elicited by imposing an Na+ gradient in energized membrane vesicles . Thus, it is concluded that the mechanism for Na+ extrusion is an Na+/H+ antiport . The Na+/H+ antiporter is a transformer which converts an electrochemical H+ gradient to an Na+ gradient, which then drives melibiose transport . Li+ was inhibitory for the growth of cells when melibiose was the sole carbon source, even though Li+ stimulated melibiose transport . This suggests that high intracellular Li+ may be harmful. J Gen Microbiol, 1980 Oct, 120(Pt 2), 385 - 92 Isolation and properties of pyruvate dehydrogenase complex mutants of Pseudomonas aeruginosa PAO; Jeyaseelan K et al.; Four independent ace mutants of Pseudomonas aeruginosa PAO lacking the activity of the pyruvate dehydrogenase complex have been isolated . They resembled ace mutants of Escherichia coli and Salmonella typhimurium in requiring acetate as an essential supplement for aerobic growth on glucose, succinate or lactate and in their ability to utilize acetate as sole carbon and energy source . Assays for the individual components of the pyruvate dehydrogenase complex indicated that they lacked the pyruvate dehydrogenase component (El) or the pyruvate dehydrogenase and dihydrolipoamide acetyltransferase components (E1 and E2) but not the lipoamide dehydrogenase component (E3) . Genetic studies with plasmid R68.45-mediated conjugation and phage F116L-mediated transduction indicated that the ace mutations are located at approximately 15 min in the P . aeruginosa PAO linkage map. J Gen Microbiol, 1980 Oct, 120(Pt 2), 355 - 67 Surface density of major outer membrane proteins in Salmonella typhimurium in different growth conditions; Aldea M et al.; The amount of major proteins per unit of surface area in the outer membrane (OM) of Salmonella typhimurium LT2 remained constant during steady-state growth in different media . Between growth rates of 2.40 doublings h-1 and 0.31 doublings h-1, the surface density of major OM proteins varied between 0.9 X 105 molecules per micrometer2, while surface area per cell more than halved . The accumulation of molecules of the major OM proteins was not affected by addition of cyclic AMP to the growth medium . When exponentially growing cells were subjected to shift-up transitions, cell dimensions began to increase after a lag period of 20 min . Accumulation of major OM proteins followed the same pattern as total protein; this created a transitory imbalance of major OM protein density in the shift from acetate minimal medium to LB medium, before the steady situation was reached . After shift-down transitions, cell dimensions began to decrease immediately, cells eventually becoming shorter than in steady-state conditions . No fluctuations in major OM protein density were observed during the shift-down, although final stable levels differed from those in steady-state conditions . All these results indicate that bacteria adapt the accumulation of major proteins into the OM according to the amount of surface . Thus, no large differences exist at different cell sizes, although transitions between media can lead to transitory or stable changes in the composition of the OM. Proc Natl Acad Sci U S A, 1980 Oct, 77(10), 6047 - 51 Regulation of Tn5 transposition in Salmonella typhimurium; Biek D et al.; The drug-resistance element Tn5 transposes with high frequency immediately after entry into a cell . Establishment of Tn5 within a cell results in a decrease in this transposition frequency . This phenomenon resembles "zygotic induction" of repressible operons and prophages . Evidence is presented that Tn5 transposition is under negative control by a factor encoded within the element itself . Established Tn5 elements (that contain point mutations inactivating the resistance gene) are able to inhibit transposition of an incoming Tn5 element by a factor of 12- to 70-fold . Several deletion derivatives of Tn5 lack the ability to inhibit transposition. J Bacteriol, 1980 Oct, 144(1), 173 - 8 Salmonella typhimurium mutants with reduced levels of transfer ribonucleic acid-inhibitable endodeoxyribonucleolytic activity; Zabel DJ et al.; Two methods of mutagenesis, chemical alkylation and insertion of the tetracycline resistance transposon Tn10, were used to generate mutants of Salmonella typhimurium which had reduced levels of endodeoxyribonucleolytic activity . The chemically induced mutations defined a locus, endA, which was cotransduced with serA at a low frequency and with metK at a high frequency . Three-factor crosses revealed that metK was between serA and endA . The major endodeoxyribonucleolytic activity in crude extracts of s . typhimurium was similar to the activity of Escherichia coli endonuclease I . A Tn10 insertion mutation of endA resulted in the most severe loss of endodeoxyribonucleolytic activity among the endA alleles studied . Two of the chemically induced mutations resulted in activities which were more thermolabile than the wild-type activity. Acta Pharmacol Toxicol (Copenh), 1980 Sep, 47(3), 175 - 82 The role of ethyl and fluorine substitution in the 4'-position for N,N-diethyl-4-aminoazobenzene mutagenicity and azo reduction; Soderlund EJ et al.; The mutagenicity and azo reduction rate of N,N-diethyl-4-aminoazobenzene (DEAB) were influenced by substitution in the 4'-position with a ethyl or a fluorine group . The parent dye (DEAB) was shown to be slightly mutagenic with Salmonella typhimurium TA98 using Aroclor 1254-pretreated 9000 x g supernatant fractions from rat liver . Introduction of a 4'-ethyl group in DEAB did not affect mutagenicity of the dye, but a 4-fluoro group markedly enhanced its mutagenicity . DEAB underwent azo reduction and its reduction rate was influenced by 4'-substituents . A 4'-fluoro group in DEAB increased its azo reduction rate, while a 4'-ethyl group abolished it . Inhibitors of cytochrome P-450 also inhibited 4'-fluoro-DEAB mutagenicity and azo reduction. J Gen Microbiol, 1980 Sep, 120(1), 21 - 6 Colicinogeny in Salmonella typhimurium; Barker RM; Colicin types, Ia, Ib, E1, E2, B with M, K, S4 and a new salmonellin-like colicin were found in 531 (11.8%) of 4481 wild-type cultures of Salmonella typhimurium . Colicin typing added little useful information to phage typing and biotyping in strain differentiation, mainly because the most common types, Ia and Ib, are controlled by conjugative plasmids . Evidence from the mixed-Col-/Col+ pattern of colicinogeny in circumscribed outbreaks caused by strains of known phage type and biotype suggested that some Col factors are readily acquired by S . typhimurium from other enteric species . When a Col factor of the nonconjugative type, e.g . ColE2, becomes established in strains of successful phage type/biotype line, it may be a useful additional marker character. Scand J Work Environ Health, 1980 Sep, 6(3), 221 - 6 Mutagenic action of isocyanates used in the production of polyurethanes; Andersen M et al.; Isocyanates used in the production of polyurethanes were investigated for mutagenic action in Salmonella typhimurium . These investigations showed that the most commonly used isocyanates, toluene diisocyanate (TDI) and 4,4'-methylene-diphenylisocyanate (MDI), are mutagenic . This effect can be ascribed to the amine analogues formed during the hydrolysis of isocyanates: TDI is mutagenic in TA 1538 and TA 98 after metabolic activation . This finding agrees with the results obtained with the amine analogue 2,4-toluenediamine . MDI, like the amine analogue 4,4'-methylenedianiline, is mutagenic in TA 100 after metabolic activation by rat liver enzymes (S-9 mix) . A prepolymerized polyisocyanate of the MDI type is also mutagenic in assays using TA 100 and S-9 mix . It is concluded that isocyanates are potentially mutagenic and carcinogenic to man . In view of their widespread use in the work environment and in light of the high production figures for polyurethanes in industrialized countries, isocyanates must be considered to represent a serious health hazard. J Environ Pathol Toxicol, 1980 Sep, 4(2-3), 401 - 25 Immunosuppression in mice induced by dioxin (TCDD) in feed; Hinsdill RD et al.; Juvenile and adult mice (4 and 7 weeks old, respectively) were fed various levels of 2, 3, 7, 8-tetracholorodibenzo-p-dioxin (TCDD) incorporated in mouse feed for five weeks or more . Animal parameters monitored included body weight, organ weights, white blood counts, hematocrits, certain serum protein levels (see below), symptoms of overt toxicity and mortality . High exposure levels (100 ppb) produced marked suppression in total serum protein, gamma globulin and albumin, but an increase in the beta-globulins . Feeding levels of 10 ppb TCDD or more reduced the primary and secondary antibody response to both tetanus toxoid and sheep erythrocytes . The amount of suppression appeared to be dose related, with juvenile animals showing greater suppression than adults . Antibody suppression from the 10 ppb feed level was roughly equivalent to that observed from a single high dose (200 mg/kg) of cyclophosphamide (CY) . No evidence of enhanced IgE synthesis was obtained from TCDD exposed animals . TCDD feeding also lowered contact sensitization to dinitrofluorobenzene and resistance to challenge with either Salmonella typhimurium or Listeria monocytogenes. Ann Microbiol (Paris), 1980 Sep-Oct, 131B(2), 153 - 61 Protective immunity and the cell-mediated immune response in mice following oral administration of an avirulent strain of Salmonella typhimurium; Ivanoff B et al.; Oral vaccination with Salmonella typhi-murium M 206 has been shown to confer highly significant protection on BALB/c and low-responder (LR) Biozzi mice a 30 days, but no protection was observed in high-responder (HR) Biozzi mice . None of the three strains showed any evidence of significant protection 10 days after primary vaccination . A correlation was noted between the degree of protection and the results of tests measuring cell-mediated immunity, both in vitro (MIF test), and in vivo (colloidal carbon clearance) . Phagocytosis was significantly more active in vaccinated mice, both at days 10 and 30, except in HR mice . MIF production was only found at day 10 in HR mice, and was present at day 30 in both HR and LR mice . Our results emphasize the importance of the role of macrophage phagocytosis in the protection of mice against Salmonella infections. Eur J Biochem, 1980 Sep, 110(2), 439 - 44 Stereochemistry of valine biosynthesis . Configuration of the product of rearrangement of alpha-acetolactate; Crout DH et al.; When alpha-aceto{1,3,5-13C3}lactate (2-hydroxy-2-methyl-3-oxo{1,3,5-13C3}butanoate) was incubated with a cell-free system prepared from Salmonella typhimurium, the valine produced was labelled in the C-4 pro-S position . This result proves that during the tertiary ketol rearrangement catalysed by the reductoisomerase of the isoleucine-valine pathway, the methyl group transfer is to the re face of the trigonal centre at C-3 of alpha-acetolactate. Mutat Res, 1980 Sep, 79(1), 59 - 71 The effect of hepatic microsomal and cytosolic subcellular fractions on the mutagenic activity of epoxide-containing compounds in the Salmonella assay; El-Tantawy MA et al.; 7 epoxide-containing compounds: allylbenzene oxide, styrene oxide, trans-beta-methylstyrene oxide, 4-chlorophenyl glycidyl ether, vinylcyclohexene dioxide, octene dioxide and hexene dioxide were evaluated for mutagenic activity in 4 histidine-requiring strains of Salmonella typhimurium, namely: TA1535, TA100, TA1537 and TA98 . These epoxides, except trans-beta-methylstyrene oxide, were mutagenic in TA1535 and TA100 but none of the tested compounds caused mutations in strains TA1537 and TA98 . Both the cytosolic (100000 g soluble) and/or microsomal (100000 g pellet) fractions derived from noninduced mouse, guinea pig, and/or rat consistently decreased the mutagenic activity of the 3 most active mutagens: allylbenzene oxide, styrene oxide and 4-chlorophenyl glycidyl ether . This reduction was found to depend on the substrate and the source of the enzyme fraction . Glutathione alone or in combination with the mouse cytosolic fraction resulted in negligible suppression in the mutagenic activity of the 3 epoxides under the conditions reported in this paper . The enzyme(s) in the cytosol responsible for the reduction in mutagenicity co-eluted from gel filtration with the epoxide hydrolase activity . These data are not consistent with the assumption that all epoxide hydrolase activity in an "S9" fraction is microsomal. Bol Med Hosp Infant Mex, 1980 Sep-Oct, 37(5), 979 - 84 {Cholestyramine in the treatment of refractory diarrhea of the newborn}; Duffau G et al.; Eleven infants with severe protracted diarrhea were studied . All of them were treated with cholestyramine, 2 g/kg/day in three or four doses . Feces became normal in two to four days in ten out of eleven infants . Tolerance to cholestyramine was good . Fat balance was performed in five patients showing steatorrhea in all of them, ranging from 15 to 42% . Reduction in resin doses was followed by normal fat excretion . Three infants died . One of them did not show improvement with cholestyramine therapy and developed Salmonella typhimurium sepsis . The other two, even though they normalized their stools, died because of Salmonella typhimurium and bacteroides sepsis respectively. Appl Environ Microbiol, 1980 Sep, 40(3), 476 - 9 Mutagenicity of islandicin and chrysophanol in the Salmonella/microsome system; Liberman DF et al.; Chrysophanol and islandicin, two anthraquinones which are structurally related to emodin, were found to be frame-shift mutagens for Salmonella typhimurium strain TA 1537 after metabolic activation. Antimicrob Agents Chemother, 1980 Sep, 18(3), 480 - 2 pJT2: unusual H1 plasmid in a highly virulent lactose-positive and chloramphenicol-resistant Salmonella typhimurium strain from calves; Timoney JF et al.; A lactose-positive and chloramphenicol-resistant strain of Salmonella typhimurium of high virulence was isolated from an outbreak of enteric and septicemic salmonellosis in veal calves . the lactose-positive marker was located on an H1 plasmid, pJT2, together with resistance to chloramphenicol, streptomycin, sulfonamides, and tetracycline, pJT2 was unusually large and had a molecular weight of about 150 X 10(6) . A similar plasmid was also present in a third of the Escherichia coli strains isolated from the intestines of septicemic calves during the outbreak . Spontaneously derived Lac- derivatives of pJT2 had an approximate molecular weight of 140 X 10(6). J Bacteriol, 1980 Sep, 143(3), 1509 - 12 Substrate channeling: alpha-ketobutyrate inhibition of acetohydroxy acid synthase in Salmonella typhimurium; Shaw KJ et al.; Excess alpha-ketobutyrate inhibited the growth of Salmonella typhimurium LT2 by inhibiting the acetohydroxy acid synthase-catalyzed synthesis of alpha-acetolactate (a valine precursor) . As a result, cells were starved for valine, and both ilvB (encoding acetohydroxy acid synthase I) and ilvGEDA (ilvG encodes acetohydroxy acid synthase II) were derepressed . The addition of valine reversed the effects of alpha-ketobutyrate. Chem Biol Interact, 1980 Sep, 31(3), 247 - 54 Measurement of drug-metabolizing systems in Salmonella typhimurium strains G46, TA15135, TA100, TA1538 and TA98; Meijer J et al.; Salmonella typhimurium strains which are commonly used in the Ames test for screening potential carcinogens were examined for a number of drug-metabolizing systems . Neither cytochrome P-450 itself nor two activities catalyzed by the cytochrome P-450 system in mammalian cells, i.e., benzpyrene monooxygenase and ethoxycoumarin O-deethylation, could be detected . Nor do these bacterial strains demonstrate any ability to detoxify epoxides by hydrating them or to conjugate p-nitrophenol with glucuronic acid . On the other hand, S . tryphimurium strains G46, TA1535, TA100, TA1538 and TA98 contain considerable amounts of acid-soluble thiols, approx . 5--10% of which is glutathione . These bacteria can also enzymatically conjugate glutathione with 1-chloro-2,4-dinitrobenzene (CDNB) and can reduce oxidized glutathione using NADPH as cofactor . Thus, enzymatic and non-enzymatic reaction of immediate carcinogens with thiol groups in s . typhimurium may have a significant effect on the outcome of the Ames test in certain cases. Mutat Res, 1980 Sep, 72(2), 257 - 64 Preliminary studies on the ability of Drosophila microsomal preparations to activate mutagens and carcinogens; Baars AJ et al.; Subcellular fractions from Drosophila melanogaster, known to have several xenobiotic-metabolizing enzymatic activities, were investigated with respect to their ability to biotransform compounds that require metabolic activation before exerting mutagenic effects . Nitrofurazone, dimethylnitrosamine, cyclophosphamide and 2-acetylaminofluorene were activated to mutagens upon incubation with Drosophila microsomes or 20000 x g supernatant: mutagenicity was observed in Chinese hamster ovary cells, Escherichia coli strains 343/113/R-9 and 343/113/uvrB, and Salmonella typhimurium TA1538 . Under the conditions used, microsomal preparations of Drosophila were not able to activate benzo{a}pyrene to a mutagen for Salmonella typhimurium TA98 . The spectrum of mutagenic effects observed shows some correlation with the known mutagenicity of these compounds in vivo in Drosophila melanogaster . Drosophila microsomes appeared to be at least as active as rat-liver microsomes when compared in this type of mutagenicity testing. Mutat Res, 1980 Sep, 79(1), 33 - 43 Non-mutagenic genotoxicants: novobiocin and nalidixic acid, 2 inhibitors of DNA gyrase; McCoy EC et al.; The antimicrobial agents nalidixic acid and novobiocin, both inhibitors of DNA gyrase, preferentially inhibit the growth of DNA repair-deficient Escherichia coli, Salmonella typhimurium and Bacillus subtilis . On the other hand, these agents exhibit no demonstrable mutagenicity for S . typhimurium and E . coli even when tested under conditions designed to take the metabolic properties of these agents into consideration . Novobiocin and nalidixic acid are widely used in animal and human medicine and further studies to assess their genetic and carcinogenic potentials appear to be in order. J Bacteriol, 1980 Sep, 143(3), 1325 - 31 Isolation of ara-lac gene fusions in Salmonella typhimurium LT2 by using transducing bacteriophage Mu d (Apr lac); Lee JH et al.; A specialized Mu transducing phage containing a gene encoding ampicillin resistance and the lac structural genes without the lac promotor {Mu d(apr lac)} has been constructed and used to create gene fusions in Escherichia coli (M . J . Cadadaban and S . N . Cohen, Proc . Natl . Acad . Sci . U.S.A . 76:4530--4533, 1979) . Transposition of the Mu d(Apr lac) phage to chromosomal sites can result in lac expression being controlled by a chromosomal promoter . We have constructed an Escherichia coli K-12 strain in which the Mu d(Apr lac) phage is integrated into an F factor . The F+::Mu d(Apr lac) was then transferred by conjugation into a Salmonella typhimurium strain that was sensitive to L-arabinose . Strains containing gene fusions were selected as L-arabinose-resistant colonies after partial induction of the phage . Two classes of ara-lac fusion strains were isolated: (i) araC-lac fusions in which the expression of beta-galactosidase synthesis was constitutuve and not inducible by L-arabinose; and ((ii) fusion of the lac genes to the ara structural genes in which the expression of beta-galatosidase synthesis was induced 263-fold by L-arabinose. Chem Biol Interact, 1980 Sep, 31(3), 355 - 65 Mutagenic and toxic effects of ruthenium; Yasbin RE et al.; Selected platinum and ruthenium complexes were tested for their ability to cause Salmonella typhimurium strains TA98 and TA100 to revert to histidine independence . The results indicate that ruthenium compounds are capable of reverting both strains while cis-Cl2(NH3)2Pt primarily causes reversions in strain TA100 . In addition, cis-platinum is an order of magnitude more mutagenic and toxic than are the ruthenium complexes . Selected compounds were also tested for their ability to induce the bacterial SOS system in the Bacillus subtilis Comptest . In this system, cis-platinum similarly showed greater inducing ability than did the ruthenium complexes . These results also demonstrated that the nature of the sixth ligand in the ruthenium compounds has a significant effect on the mutagenic capacity of these agents. J Bacteriol, 1980 Sep, 143(3), 1524 - 6 Genetic mapping of the Salmonella typhimurium pepB locus; Green L et al.; Transposon technology has been used to map the pepB locus of Salmonella typhimurium . This locus is cotransducible by phage P22 with glyA and strB at min 56 on the Salmonella genetic map . The gene order is strB pepB glyA. Chem Phys Lipids, 1980 Sep, 27(2), 177 - 83 Studies of the fatty acid composition and membrane microviscosity in Salmonella typhimurium TA98; Hampton MJ et al.; When the mutagen tester bacterial strain Salmonella typhimurium TA 98 was grown at different temperatures, we found that the unsaturated fatty acid composition increased at the lower growth temperatures . Membrane microviscosity, as assessed with spin-probe fatty acids using electron spin resonance, decreased as the unsaturated fatty acid content increased . These findings are of importance in understanding our recent observation that the mutagenic response of these bacteria was increased when they were grown at 27 degrees C vs . 37 degrees C, and indicate that membrane properties may play an important role in the sequence of events leading to mutagenesis. Cell Biophys, 1980 Sep, 2(3), 177 - 89 Association with HeLa cells of LPS mutants of Salmonella typhimurium and Salmonella minnesota in relation to their physicochemical surface properties; Kihlstrom E et al.; Different LPS mutants of Salmonella typhimurium and Salmonella minnesota have been investigated with respect to (1) their tendency to associate with HeLa cell monolayers, and (2) their physicochemical surface properties . Aqueous biphasic partitioning, hydrophobic interaction chromatography, and ion exchange chromatography have been used to characterize the bacterial cell surface properties with respect to charge and hydrophobicity . Liability to hydrophobic interaction was defined either by the change of partition in a dextran-polyethylene-glycol (PEG) system by the addition of PEG-palmitate (P-PEG), or by the elution pattern from Octyl-Sepharose . Accordingly, charge was asssessed by the effect of positively charged trimethylamino-PEG (TMA-PEG) on the partition, and by the elution from DEAE-Sephacel . Bacterial being negatively charged and liable to hydrophobic interaction had the highest tendency to associate with HeLa cells . In some cases the methods for surface analysis gave conflicting results on charge and/or liability to hydrophobic interaction of the same LPS mutant . Possible reasons for these differences and the role of bacterial cell surface structures contributing to physicochemical character are discussed. J Membr Biol, 1980 Aug 21, 56(1), 19 - 29 Determination of ion permeability through the channels made of porins from the outer membrane of Salmonella typhimurium in lipid bilayer membranes; Benz R et al.; The three types of porin (matrix-proteins) from Salmonella typhimurium with molecular weights of 38,000, 39,000 and 40,000 were reconstituted with lipid bilayer membranes either as a trimer or as an oligomer (complex I) . The specific conductance of the membranes increased several orders of magnitude after the addition of the porins into the aqueous phase bathing the membranes . A linear relationship between protein concentration in the aqueous phase and membrane conductance was found . In the case of lower protein concentrations (10)(-12)M), the conductance increased in a stepwise fashion with a single conductance increment of 2.3 nS in 1 M KC1 . For a given salt the conductance increment was found to be largely independent of the particular porin (38 K, 39 K or 40 K) and on the state of aggregation, although porin oligomers showed an up to 10 times smaller conductance increase in macroscopic conductance measurements . The conductance pathway has an ohmic current voltage characteristic and a poor selectivity for different alkali ions . Further information on the structure of the pores formed by the different porins from Salmonella was obtained from the selectivity for various ions . From the permeability of the pore for large ions (Tris+, glucosamine+, Hepes-) a minimum pore diameter of 0.8 nm is estimated . This value is in agreement with the size of the pore as calculated from the conductance data for 1 M KC1 (1.4 nm for a pore length of 7.5 nm) . The pore diameter may well account for the sugar permeability which has been found in reconstituted vesicles . The findings reported here are consistent with the assumption that the different porins form large aqueous channels in the lipid bilayer membranes and that the single conductance unit is a trimer . In addition, it is suggested that one trimer contains only one pore rather than a bundle of pores. J Environ Pathol Toxicol, 1980 Aug, 4(1), 55 - 65 Differential effects of cytochrome P450-inducers on promutagen activation capabilities and enzymatic activities of S-9 from rat liver; Ong T et al.; Studies have been conducted to determine aryl hydrocarbon hydroxylase, benzphetamine-N-demethylase, epoxide hydrase and glutathione S-transferase activities and cytochrome P-450 content in the liver 9000xg supernatant fractions from rats treated with either phenobarbital, beta-naphthoflavone, ARoclor 1254 or a combination of phenobarbital and beta-naphthoflavone . The metabolic activation of 2-anthramine, 2-acetylaminofluorene, 3-methylcholanthrene, and benzo(a)pyrene to metabolites that are mutagenic in Salmonella typhimurium TA1535 or TA98 by S-9 from rats treated with these inducers was also determined . The induction of drug metabolizing enzymes in the S-9 from Aroclor or phenobarbital plus beta-naphthoflavone treated animals was very similar . The overall results seem to indicate that a combination treatment of phenobarbital and beta-naphthoflavone can be used as a substitute for Aroclor 1254 as inducer for enzyme activity and for the in vitro activation of promutagens to mutagenic metabolites in Salmonella mutagenesis assay systems. J Gen Microbiol, 1980 Aug, 119(Pt 2), 517 - 25 Immunological properties of the cell envelope components of Vibrio cholerae; Kabir S et al.; Several immunobiological properties of cell envelope components of Vibrio cholerae such as mitogenicity, antigenicity, adjuvanticity and toxicity were tested in mice . Killed whole bacteria, spheroplasts, lipopolysaccharide and outer membrane proteins possessed mitogenic activity as determined by {3H}thymidine uptake in spleen cell cultures . All these components predominantly stimulated murine bone-marrow derived (B) lymphocytes . The mitogenicity induced by V . cholerae lipopolysaccharide was similar in magnitude to that observed with Salmonella typhimurium lipopolysaccharide . Vibrio cholerae lipopolysaccharide was mitogenic for gut-associated lymphocytes such as those obtained from Peyer's patches and small intestine . Antibody formation at the cellular level was detected by the haemolytic plaque assay . Plaque-forming cells to V . cholerae lipopolysaccharide were only detected when mice were immunized intraperitoneally with intact cells or with spheroplasts . Among the various cell envelope components, lipopolysaccharide alone possessed adjuvant properties as it increased the number of plaque-forming cells to sheep erythrocytes fourfold in mouse spleens . Also, lipopolysaccharide was the only component found to be toxic for the mouse (LD50 0 . 5 mg) . Neither spheroplasts nor outer membrane of V . cholerae showed adjuvanticity or toxicity in mice. J Bacteriol, 1980 Aug, 143(2), 801 - 8 Regulation of nitrogen utilization of hisT mutants of Salmonella typhimurium; Rosenfeld SA et al.; Mutations in the hisT gene of Salmonella typhimurium alter pseudouridine synthetase I, the enzyme that modifies two uridines in the anticodon loop of numerous transfer ribonucleic acid species . We have examined two strains carrying different hisT mutations for their ability to grow on a variety of nitrogen sources . The hisT mutants grew more rapidly than did hisT+ strains with either arginine or proline as the nitrogen source and glucose as the carbon source . The hisT mutations were transduced into new strains to show that these growth properties were due to the hisT mutations . The hisT mutations did not influence the growth of mutants having altered glutamine synthetase regulation . Assays of the three primary ammonia-assimilatory enzymes, glutamate dehydrogenase, glutamine synthetase, and glutamate synthase, showed that glutamate synthase activities were lower in hisT mutants than in isogenic hisT+ controls; however, the glutamate dehydrogenase activity was about threefold higher in the hisT strains grown in glucose-arginine medium . The results suggest that the controls for enzyme synthesis for nitrogen utilization respond either directly or indirectly to transfer ribonucleic acid species affected by the hisT mutation. J Bacteriol, 1980 Aug, 143(2), 747 - 52 Locations of the opp and supX genes of Salmonella typhimurium and Escherichia coli; Lenny AB et al.; The chromosomal locations of the supX and opp loci of Salmonella typhimurium LT2 and Escherichia coli K-12 were identified and found to result in the same gene sequence in both species, namely, pyrF-cysB-supX-trpPOLEDCBA-tonB(chr)-opp . These results differ from a previously reported location of the opp gene on the E . coli chromosome . Evidence indicates that the opp gene lies between chr(tonB) and galU in S . typhimurium. J Bacteriol, 1980 Aug, 143(2), 644 - 51 Polyprenyl p-hydroxybenzoate carboxylase in flagellation of Salmonella typhimurium; Howlett BJ et al.; Flagellation of Salmonella typhimurium was found to require a functional pathway for ubiquinone biosynthesis as well as growth in the presence of appropriate carboxylic acids . Induction of flagellation by carboxylic acids was shown to induce incorporation of p-hydroxybenzoic acid into polyprenylphenol . Constitutive flagellation was found to correlate with constitutive incorporation of p-hydroxybenzoic acid into polyprenylphenol . A novel pathway for polyprenyl p-hydroxybenzoic acid decarboxylation to polyprenylphenol was implicated in flagellation of S . typhimurium. J Bacteriol, 1980 Aug, 143(2), 637 - 43 Ubiquinone synthetic pathway in flagellation of Salmonella typhimurium; Bar-Tana J et al.; Flagellation of Salmonella typhimurium was found to require a functional pathway for ubiquinone synthesis as well as growth in the presence of aliphatic or aromatic carboxylic acids . Selection for constitutive flagellation eliminated the requirement for growth in the presence of added carboxylic acids. J Bacteriol, 1980 Aug, 143(2), 1019 - 24 Morphogenesis of the bacterial division septum: identification of potential sites of division in lkyD mutants of Salmonella typhimurium; Fung JC et al.; It previously has been shown that lkyD mutants of Salmonella typhimurium form large blebs of outer membrane over the septal and polar regions of dividing cells . To determine whether the outer membrane blebs are formed over potential sites of division even in the absence of septal ingrowth, lkyD strains were studied under conditions in which ingrowth of inner membrane and murein was prevented by inactivation of the envA gene product . In aseptate filaments of the LkyD EnvA strain, outer membrane blebs occurred with the usual frequency and were preferentially located over regions where new septa were formed when cell division was subsequently permitted to resume . The results indicate that the outer membrane blebs of the LkyD strain are markers for potential sites of cell division, implying that an alteration in association of outer membrane and murein exists in these sites before the initiation of septal ingrowth . This localized change in cell envelope organization is independent of the septation-inducing effects of the envA gene product. Cancer Lett, 1980 Aug, 10(2), 141 - 9 Amino-alpha-carbolines as mutagenic agents in cigarette smoke condensate; Yoshida D et al.; Two mutagenic agents, 2-amino-9H-pyrido{2,3-b)indole and 2-amino-3-methyl-9H-pyrido{2,3-b}indole (amino-alpha-carbolines) have been isolated from cigarette smoke condensate for this study . The former agent varied in amounts from a low of 25 ng/cigarette in the smoke of flue-cured tobacco, to a high of 258 ng/cigarette in a cigarette of Japanese domestic variety . The latter ranged in amounts from 9 to 37 ng/cigarette . The contents of these mutagens in the smoke condensate were positively related to an increase in mutagenic activity of Salmonella typhimurium TA 98. Mutat Res, 1980 Aug, 78(4), 353 - 60 The mutagenic effect of the new insecticide and acaricide pyridathion; Vargova M et al.; The potential mutagenic effect of the new organophosphate insecticide and acaricide, pyridathion, was tested on Escherichia coli, strains WP2, WP2 uvrA, and on Salmonella typhimurium, strains TA100 and TA98, both with and without metabolic activation . The compound was tested at 1, 10 and 100 micrograms/ml . The analysis of chromosomal aberrations in mouse bone marrow was performed after a single peroral application of pyridathion at doses of 0.6, 1.11, 6.0, 12.0 and 24.0 mg . kg-1 b.w., i.p . application at 6.0 mg . kg-1 b.w., and repeated application (5 times) p.o . at 1.0, 2.5 and 5.0 mg . kg-1 b.w . Analysis of rat bone marrow was performed after a 3-month peroral application of pyridathion at 0.07, 0.175 and 0.35 mg . kg-1 b.w . An analysis of chromosomal aberrations in human peripheral lymphocytes in vitro was performed 24 h after the application of pyridathion into the culture in concentrations of 9.2 X 10(-3), 9.2 X 10(-4) and 9.2 X 10(-5) moles . The insecticide did not exert any mutagenic effect on the bacteria . There was no significant increase in the frequency of chromosomal abnormalities in bone marrow of mice of rats, or in human peripheral lymphocytes in vitro, compared with controls. Mutat Res, 1980 Aug, 78(4), 331 - 9 Inactivation of mutagens from pyrolysates of tryptophan and glutamic acid by nitrite in acidic solution; Tsuda M et al.; The mutagenic aromatic amines Trp-P-1, Trp-P-2 and Glu-P-1, isolated frm pyrolysates of tryptophan and glutamic acid, at the concentration of 0.025 mM were treated with 0.05 mM nitrite at various pH values at 37 degrees C . The resulting reaction mixtures were tested for mutagenicity towards Salmonella typhimurium TA98 and TA100 . When treated with nitrite at this physiologically realistic concentration, these mutagenic aromatic amines were readily converted to extremely weak or non-mutagenic deaminated compounds . These deaminated products were identified as the corresponding hydroxy compounds by mass and proton magnetic resonance spectroscopies . Comparative kinetic studies were made on the disappearance of the mutagenic aromatic amines . The half-life (t1/2 of Glu-P-1 on treatment with nitrite at pH 1.6 was less than 5 min, and those of Trp-P-1 and Trp-P-2 were 95 and 105 min, resp. Mutat Res, 1980 Aug, 72(1), 79 - 89 Bioactivation of dimethylnitrosamine in intrasanguinous host-mediated assay and its association with in vitro mutagenesis assays; Bakshi K et al.; These studies have revealed the usefulness of in vivo intrasanguine host-mediated assay (HMA) to detect point mutations . Mutations were found to occur at a significant rate in Salmonella typhimurium G-46 employed as indicator organisms recovered from liver, lung, kidney and spleen of DMN-treated animals compared to negative control animals . These differences were true for both male and female animals . The number of Salmonella typhimurium G-46 recovered from the testes was not large enough to make a valid judgment about mutations occurring in testes . The results from in vitro studies do not match with the in vivo host-mediated assay results for mutants occurring in spleen from the male and the female mice . The results also do not correlate for in vitro and in vivo studies involving female kidneys . These results suggest there may be no one-to-one correlation between the organ bioactivation in vitro and in vivo, and predictions of in vivo target organ cannot always be made from in vitro studies with isolated microsomal enzymes. Mutat Res, 1980 Aug, 72(1), 73 - 7 Enhancement of the mutagenicities of N-methyl-N'-nitro-N-nitrosoguanidine and N-methyl-N-nitrosourea by glucose; Shirai A et al.; The mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine to Salmonella typhimurium hisG46 was enhanced by pre-incubating the chemical with bacteria in sodium phosphate buffer . Addition of glucose (to 15 mM) to the pre-incubation mixture further enhanced the mutagenicity . Pre-incubation with glucose also increased the mutagenicity of N-methyl-N-nitrosourea . Fructose, galactose, pyruvate and succinate also enhanced the mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine . The effect of glucose was observed with S . typhimurium strains hisG46, TA1975, TA1950, TA1535 and TA100. Mutat Res, 1980 Aug, 72(1), 63 - 72 Substrates and inhibitors of hepatic amine oxidase inhibit dimethylnitrosamine-induced mutagenesis in Salmonella typhimurium; Rowland IR et al.; The mutagenic effect of dimethylnitrosamine in Salmonella typhimurium TA100, in the presence of a rat-liver homogenate derived from animals treated with Aroclor 1254, was inhibited by substrates and inhibitors of monoamine oxidase . Substrates of diamine oxidase did not inhibit dimethylnitrosamine mutagenesis and, furthermore, monoamine oxidase inhibitors had no effect on mutagenesis by benzo{a}pyrene or aflatoxin B1 . The results suggest that monoamine oxidase participates in the activation of dimethylnitrosamine to a mutagen. Biull Eksp Biol Med, 1980 Aug, 90(8), 208 - 10 {Mutagenic action of benz(a)pyrene and its metabolites in the in vitro Salmonella typhimurium-microsomes test system}; Tolcheev IuD et al.; It has been shown that epoxides are responsible for the mutagenic action of benz(a)pyrene in the system . S . typhimurium . The mutagenic effect produced by 6-hydroxybenz(a)pyrene that is consequent on the free radical processes is reversed by alpha-tocopherol . Diolepoxides with spatially separated functional groups do not elicit any mutagenic effect. Toxicol Lett, 1980 Aug, 6(3), 125 - 30 The mutagenicity of butadiene towards Salmonella typhimurium; de Meester C et al.; Gaseous butadiene (BUT) was mutagenic towards S . typhimurium strain TA 1530 when the incubation mixture was supplemented with a NADPH-fortified rat liver microsomal preparation; mutagenicity increased with the dose . A significant mutagenic effect was similarly observed when the petri dishes, containing the bacteria but no metabolic activation system, were incubated in the presence of butadiene, in a desiccator in which plates containing the S-9 rat liver fraction had been placed . This indirect mutagenic effect was attributed to the formation, by the S-9 mix, of volatile intermediate(s) that migrated and induced mutations in neighbouring bacteria. J Natl Cancer Inst, 1980 Aug, 65(2), 321 - 6 Mutagens in extracts of human gastric mucosa; Stemmermann GN et al.; Extracts of mucosa from 53 stomachs were tested for mutagenicity with the use of Salmonella typhimurium strains TA98 and TA100 . Mutagenic activity was observed in nonneoplastic mucosa from seven stomachs with S . typhimurium strain TA98 without the S- . mix (a rat liver microsomal enzyme preparation) and in three stomachs with TA100 without S- . mix . All of the TA98 mutagenic samples were derived from stomachs showing evidence of intestinal metaplasia . The exception was an extract of corpus mucosa that was mutagenic with strain TA100 . "Transnitrosoase" activity was found in 12 of 53 samples, all of which showed TA98 mutagenicity . Whether the presence of mutagens and transnitrosoase activity causes intestinal metaplasia or results from it is uncertain. J Bacteriol, 1980 Aug, 143(2), 864 - 71 Utilization of 2,6-diaminopurine by Salmonella typhimurium; Garber BB et al.; The pathway for the utilization of 2,6-diaminopurine (DAP) as an exogenous purine source in Salmonella typhimurium was examined . In strains able to use DAP as a purine source, mutant derivatives lacking either purine nucleoside phosphorylase or adenosine deaminase activity lost the ability to do so . The implied pathway of DAP utilization was via its conversion to DAP ribonucleoside by purine nucleoside phosphorylase, followed by deamination to guanosine by adenosine deaminase . Guanosine can then enter the established purine salvage pathways . In the course of defining this pathway, purine auxotrophs able to utilize DAP as sole purine source were isolated and partially characterized . These mutants fell into several classes, including (i) strains that only required an exogenous source of guanine nucleotides (e.g., guaA and guaB strains); (ii) strains that had a purF genetic lesion (i.e., were defective in alpha-5-phosphoribosyl 1-pyrophosphate amidotransferase activity); and (iii) strains that had constitutive levels of purine nucleoside phosphorylase . Selection among purine auxotrophs blocked in the de novo synthesis of inosine 5'-monophosphate, for efficient growth on DAP as sole source of purine nucleotides, readily yielded mutants which were defective in the regulation of their deoxyribonucleoside-catabolizing enzymes (e.g., deoR mutants). Am Ind Hyg Assoc J, 1980 Aug, 41(8), 576 - 83 Animal toxicity studies with ammonium perfluorooctanoate; Griffith FD et al.; These studies were conducted to evaluate the potential toxicity of ammonium perfluorooctanoate, a commercial surfactant . They include acute and subchronic feeding studies with rabbits, mice, rats and monkeys as well as in vitro mutagenicity assays with Salmonella typhimurium and Saccharomyces cerevisiae . The compound was non-irritating to the skin and moderately irritating to the eyes of rabbits . The rat oral LD50 was 540 mg/kg; no deaths resulted from a one hour rat inhalation exposure at a nominal concentration of 18.6 mg/L . All in vitro assays were negative . The liver was the target organ in rodents in both the 28 day and 90 day feeding studies with males showing a greater response than females . Serum and liver concentrations of organic fluorine were greater in male than in female rats . In a 90 day oral study in rhesus monkeys the gastrointestinal tract and the reticuloendothelial system were the sites of toxic effects . The gastrointestinal effects were attributed to the potent surface activity of the compound . Histopathological effects wer noted in the spleen, lymph nodes and bone marrow . Unlike the rats, sex related differences were not evident in the monkeys . Toxicological evaluations of ammonium perfluorooctanoate are continuing. J Bacteriol, 1980 Aug, 143(2), 1081 - 5 Isolation and Characterization of acetate kinase and phosphotransacetylase mutants of Escherichia coli and Salmonella typhimurium; LeVine SM et al.; Mutations in the ack (acetate kinase) and pta (phosphotransacetylase) genes in Salmonella typhimurium were characterized and determined to be analogous to those of previously described Escherichia coli mutants . We established that in both bacterial species these genes were cotransducible with the neighboring histidine transport operon and were distally located relative to purF . pta mutants were sensitive to the dye alizarin yellow and were unable to grow on medium containing inositol as a carbon source . We selected mutants of both species with deletions covering both the ack and the pta genes; some deletions extended into the histidine transport operon. Mutat Res, 1980 Aug, 78(4), 301 - 15 Induction of prophage and mutagenic effects by alkyl alkylaminosulfonates, ethyl aminosulfonate and alkyl methanesulfonates; Sussmuth R; Prophage induction and mutation by alkylaminosulfonates, ethyl aminosulfonate and alkyl methanesulfonates were examined comparatively . Prophage induction was carried out with a lysozyme lysis technique on the lysogenic strain Micrococcus lysodeikticus 53-40 (N5) . The sulfonic ester derivatives show a slight lysogenic induction . At higher concentrations their toxicity seems to mask phage detection . Only methyl isopropylaminosulfonate and ethyl aminosulfonate exhibit no or negligible toxic effects, and with these compounds at higher concentrations a strong prophage induction is found . Alkyl sulfonate derivatives induce mutations in the tester strain of Salmonella typhimurium TA1535 . Methyl methylaminosulfonate and ethyl N-methyl-N-2-chloroethyl aminosulfonate show a mutagenicity comparable to that of the well-known methyl methanesulfonate or ethyl methanesulfonate . With ethyl aminosulfonate, however, which does not show inactivation, no significant mutagenic effect was observed . DNA alterations were found in the polymerase-deficient strain E . coli P3478 . The results of prophage induction and mutagenicity are compared and discussed. Biochim Biophys Acta, 1980 Jul 10, 614(1), 185 - 95 Studies on the enzymatic synthesis of enterochelin in Escherichia coli K-12, Salmonella typhimurium and Klebsiella pneumoniae . Physical association of enterochelin synthetase components in vitro; Greenwood KT et al.; Further evidence is presented in support of the proposal made previously (Greenwood, K.T . and Luke, R.K.J . (1976) Biochim . Biophys . Acta 454, 285-297) that components of the Escherichia coli enterochelin synthetase system physicaloly associate to form enzyme complexes . Evidence for the existence of three enzyme complexes, designated in order of increasing stability G-D < F-D < F-D-G, has been obtained following gel filtration and chromatography on DEAE-Sephadex . Persistence of the F-D and G-D complexes during chromatography appears to depend on the flow rate of the column . On the basis of complementation with appropriate ent mutants of E . coli, activities corresponding to those of the D, E, F and G components of enterochelin synthetase in E . coli have been detected in cell-extracts of both Salmonella typhimurium and Klebsiella pneumoniae (formerly Aerobacter aerogenes) strains . These are designated D', E', F' and G' activities . Components E' and G' are eluted from Sephadex G-100 in similar fashion to their E . coli counterparts . Peaks of F' and D' activities however, are eluted together at a position corresponding to that of the E . coli F component . We suggest that in S . typhimurium and K . pneumoniae, either a single polypeptide combines the functions of the E . coli F and D components, or that separate F' and D' components form a stable complex and that activity of uncomplexed D' and component was not detected under the conditions used during chromatography and assay. Avian Dis, 1980 Jul-Sep, 24(3), 604 - 15 Observations on competitive exclusion for preventing Salmonella typhimurium infection of broiler chickens; Rigby CE et al.; In 3 separate trials, groups of 180-200 one-day-old broiler chicks were treated with a lyophilized extract of breeder flock litter, an anaerobic culture of this extract, and an anaerobic culture of adult chicken feces, respectively . They were placed on litter, exposed at 3 days of age to Salmonella typhimurium placed in the drinking water and reared to 7-8 weeks (market age) . Culture of litter samples, and of the intestines of all chicks that died or were killed throughout the growing period, showed that the incidence of infection at market age was significantly lower in treated chickens than in untreated controls. Genetics, 1980 Jul, 95(3), 545 - 59 Conditionally expressed missense mutations: the basis for the unusual phenotype of an apparent trpD nonsense mutant of Salmonella typhimurium; Tanemura S et al.; Tryptophan auxotroph trpo-28 is anomalous since preliminary mapping and suppression studies indicate the presence of a single amber nonsense mutation either late in trpE or early in trpD, but enzymological tests indicate the complete inactivation of both genes in this strain . Since the trpE and trpD genes are contiguous and encode the two subunits of a multifunctional enzyme complex, it was of interest to learn the mechanism of action of this apparent pleiotropic nonsense mutation . Our study has revealed that the phenotype of this strain derives not from a single mutation, but from the presenc and interaction of multiple mutations . Besides the recognized amber mutation (designated trpD28), this strain carries two additional, conditionally expressed missense mutations (designated trpE1651 and trpD1652) . The trpD28 amber codon maps in the promoter-proximal region 1 of trpD and eliminates the glutamine amidotransferase activity of the bifunctional trpD polypeptide . The trpD1652 mutation maps in the promoter-distal region 2 of trpD and severely reduces (but does not eliminate) the phosphoribosyl transferase activity of the trpD polypeptide . The trpE1651 mutation maps in the anterior part of trpE and causes a rapid loss of activity of the trpE polypeptide, but only when it exists as an umcomplexed subunit . The existence of the two missense mutations escaped prior notice in standard recombinational tests since the nature of ech mutation is such that neither is detectable by the nutritional screens normally used in such tests unless an unsuppressed chain-terminating mutation, such as trpD28, is also present. Mutat Res, 1980 Jul, 78(3), 233 - 42 The mutagenic action of quindoxin, carbadox, olaquindox and some other N-oxides on bacteria and yeast; Voogd CE et al.; The mutagenic action of 3 coccidiostatic chinoxaline-N-oxide derivatives, quindoxin, carbadox and olaquindox, was investigated by Luria and Delbruck's fluctuation test, with Klebsiella pneumoniae and Escherichia coli K12 as test organisms . These compounds were mutagenic at very low concentrations (2 X 10(-5)--500 X 10(-5) mmole/l) . In the Ames test they showed a mutagenic action without metabolic activation with Salmonella typhimurium TA98 and TA100 at concentrations of 0.001-0.1 mmole/l in the top agar . Hence, these compounds cause both base-pair substitutions and frame-shift mutations . When Saccharomyces cerevisiae D4 was cultivated in the presence of the compounds, an increase in the mitotic gene conversions was observed . Certain other N-oxides also showed a mutagenic action in the fluctuation test . With Klebsiella pneumoniae, 4-nitroquinoline 1-oxide was mutagenic at a concentration of 0.005 mmole/l, quinoline 1-oxide at 10 mmole/l and benzofuroxan at 0.01 mmole/l . In this test no mutagenic action was found with 4-nitropyridine 1-oxide, pyridine 1-oxide or 4-picoline 1-oxide . With Salmonella typhimurium TA98 and TA100, 4-nitroquinoline 1-oxide, benzofuroxan and 4-nitropyridine 1-oxide were mutagenic, whereas quinoline 1-oxide, pyridine 1-oxide and 4-picoline 1-oxide were not . In contrast, with the fluctuation test, 4-nitroquinoline 1-oxide appeared to be more mutagenic than quindoxin, carbadox and olaquindox in the plate incorporation test. Mutat Res, 1980 Jul, 78(3), 227 - 31 Mutagenic activity of vinyl compounds and derived epoxides; Simmon VF et al.; Many vinyl compounds, such as vinyl chloride and some inhalational anesthetics, are known to be mutagens . In the present study, 10 vinyl compounds or derived epoxides, widely used in industry, were assayed in the Salmonella typhimurium/mammalian microsome system . 3 strains of histidine-dependent S . typhimurium, TA1535, TA98 and TA100 were used . Of the 10 compounds, 4 were mutagens . They were 9-vinylanthracene, vinylcarbazole, 3-vinyl-7-oxabicyclo{4.1.0}heptane and 3-epoxyethyl-7-oxabicyclo{4.1.0}-heptane . The study confirmed the overall genotoxicity of vinyl compounds and epoxides and the need to carefully screen them for mutagenic/carcinogenic effects. Mutat Res, 1980 Jul, 78(3), 219 - 26 Studies on metabolism and toxicity of styrene: III . The effect of metabolic inactivation by rat-liver S9 on the mutagenicity of phenyloxirane toward Salmonella typhimurium; Yoshikawa K et al.; A comparative study on enzymic factors influencing the metabolic inactivation of phenyloxirane (styrene oxide), a major mutagenic metabolite of styrene in the liver, was carried out with respect to soluble glutathione S-transferase and microsomal epoxide hydratase in the 9000 X g supernatant fraction (S9) from a rat-liver homogenate . The mutagenic activity of phenyloxirane to Salmonella typhimurium TA100 was markedly reduced by S9 in the presence of glutathione but to a smaller extent in its absence . The retarding effect of glutathione on the inherent mutagenic activity of phenyloxirane was exerted by the soluble supernatant of S9 but not by microsomes . A gas-liquid chromatographic study indicated that the effect of glutathione was attributable to the disappearance of the mutagen from the microbial assay system . The rate of the disappearance was 10-20 times as fast in the soluble supernatant fraction as in the microsomes when fortified with more than 4 mM glutathione . Our results strongly suggest that in hepatic cells of the rat, cytosol glutathione S-transferase plays a much more important role than microsomal epoxide hydratase in the detoxication of the metabolite, phenyloxirane. Mutat Res, 1980 Jul, 78(3), 213 - 8 Studies on the mutagenicity of resorcinol and hydroxy-3-(p-amino)anilino-6,N-{(p-amino)phenol}benzoquinone-monoimine-1,4 in Salmonella typhimurium; Shahin MM et al.; The hair-dye coupler resorcinol and the oxidation product of p-phenylenediamine d resorcinol, hydroxy-3-(p-amino)anilino-6,N-{(p-amino)phenol}benzoquinonemonoimine-1.4, were tested for mutagenicity in the histidine-requiring mutants of Salmonella typhimurium (TA100, TA1535, TA1537, TA1538 and TA98) . The investigations were carried out in the absence and presence of rat-liver homogenate induced by Aroclor 1254 and the components of the NADPH-generating system . There was no indication of mutagenic activity by these 2 compounds at any of the 8 concentrations used . The nuclear magnetic resonance spectrum of the reaction product of p-phenylenediamine and resorcinol was recorded and is in agreement with its chemical structure. Biull Eksp Biol Med, 1980 Jul, 89(7), 92 - 5 {Relationship between the presence of plasmid pKM101 and the frequency of spontaneous and induced mutations of different kinds}; Abdukhalykova GF et al.; Ames tester strains of Salmonella typhimurium containing plasmid pKM101 have been shown to be very sensitive to UV-induced base substitutions and frameshift mutations . Plasmid pKM101 mediates the ability for base substitutions through frameshift inducing mutagens and slightly enhances frameshift mutagenesis . For the agents mainly inducing base-pair substitutions, plasmid pKM101 is found to enhance slightly the rate of base-pair substitutions but not the rate of frameshift mutations. Mutat Res, 1980 Jul, 71(2), 169 - 79 Mutagenicity and DNA-damaging activity for several pesticides tested with Bacillus subtilis mutants; Shiau SY et al.; The active pure compounds of 4 pesticides were tested for DNA-damaging and mutagenic activity in Bacillus subtilis and Salmonella typhimurium tester strains . Included were zinc ethylenebisdithiocarbamate (dithane), 1,2-dihydropyridazine-3,6-dione (maleic hydrazide), O,O-dimethylphosphorodithioate (malathion), and 1,2-dibromoethane (fumazone) . These agents gave either weak or negative mutagenic responses with the Salmonella/microsome tests for mutagenicity, but were all positive when the tester was B . subtilis strain TKJ6321 . Of the 4 chemicals, only fumazone required metabolic activation with rat-liver S9 mix . Upon activation, it produced a volatile mutagenic product . Dithane, maleic hydrazide, and malathion were all mutagenic and did not require metabolic activation . Among these agents, dithane was strongly mutagenic while fumazone, maleic hydrazide and malathion were moderately mutagenic . Only dithane gave significant DNA-damaging activity when applied to a battery of repair-deficient B . subtilis mutants . For the chemicals reported, it is concluded that B . subtilis is superior to S . typhimurium in the detection of mutagenic activity . We strongly recommend its use for prescreening procedures in combination with the S . typhimurium testers. Cancer Res, 1980 Jul, 40(7), 2596 - 600 Metabolic activation of mutagenic tryptophan pyrolysis products by rat liver microsomes; Ishii K et al.; In an attempt to determine whether cytochrome P-450 metabolizes tryptophan pyrolysis products, 3-amino-1,4-dimethyl-5H-pyrido{4,3-b}indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido{4,3-b}indole (Trp-P-2) to active forms, studies were done using microsomes and the 9000 x g supernatant (S-9) from polychlorinated biphenyl mixture-treated rat livers together with Salmonella typhimurium TA 98 as a tester strain . The number of revertants increased with increments in the amount of S-9 fraction added . The highest mutation was seen with an amount of S-9 that is equivalent to 2.5 mg of liver tissue; however, further increase in the S-9 fraction resulted in a sharp decline in the number of revertants . There was a similar biphasic response when a relatively large amount of S-9 fraction was incubated for an increasing length of time . Microsomes showed parallel biphasic responses, and, in addition, the 105,000 x g supernatant fraction was ineffective in increasing the number of revertants . These results suggested that most if not all of the ability of the S-9 fraction to convert Trp-1 and Trp-P-2 to active forms resided in the microsomes . The involvement of microsomal cytochrome P-450 in this process was further confirmed by the following evidence . The treatment of rats with polychlorinated biphenyl mixture and 3-methylcholanthrene resulted in a marked increase in the ability of microsomes to activate Trp-P-1 and Trp-P-2, and the activation reaction required reduced nicotinamide adenine dinucleotide phosphate as a cofactor and was inhibited by carbon monoxide, 7,8-benzoflavone, n-octylamine, and 2-diethylaminoethyl-2,2-diphenylvalerate . The mutagenic metabolite formed as a result of microsomal metabolism of Trp-P-2 was fairly stable and survived heating at 90 degrees for 7 min . With a high-performance liquid chromatography, an active metabolite of Trp-P-2 was purified . A preliminary analysis showed this molecule to be an N-hydroxylated derivative of Trp-P-2. Cell, 1980 Jul, 20(3), 749 - 60 Secretion of beta-lactamase requires the carboxy end of the protein; Koshland D et al.; Synthesis and secretion of beta-lactamase were studied in Salmonella typhimurium infected with P22 phage carrying the structural gene for beta-lactamase (the bla gene) in mutant or wild-type form . The wild-type gene was shown to specify two forms of beta-lactamase which differ in molecular weight by about 2500 daltons . This difference is consistent with removal, predicted on other grounds, of 23 amino-terminal residues (the "signal" sequence) . All bla- mutants, including chain-terminating mutants lacking as much as 50% or as little as 10% of the protein, were apparently unaffected in this processing step . Pulse-chase experiments showed that more than 85% of the wild-type (as well as mutant) proteins are synthesized as complete overlength precursors before being processed to their mature forms . Virtually all the mature wild-type protein appears in the periplasmic space whereas a large fraction of the precursor appears in the cytoplasm . In contrast, both the precursor and processed forms of beta-lactamase proteins synthesized by chain-terminating mutants (including one which lacks only 10% of its residues from the carboxy end) are not secreted and apparently remain soluble in the cytoplasm . These results show that the carboxy-terminal amino acid sequence (at least) of beta-lactamase is essential to successful transport across the cytoplasmic membrane, and suggest that the presence (and probably also the act of removal) of the signal sequence does not suffice to ensure secretion. J Natl Cancer Inst, 1980 Jul, 65(1), 149 - 54 Mutagenic activity of nitrosourea antitumor agents; Franza BR Jr et al.; The relative mutagenic activities of chloroethyl-nitrosourea and methylnitrosourea antitumor agents in active clinical use were determined with the use of the Ames Salmonella typhimurium assay . The results indicated that the drugs induced base substitutions . 2-Deoxy-2-{{(methylnitrosoamino)carbonyl}amino}-D-glucopyranose (also called streptozotocin), a glucose-containing methylnitrosourea, was the most mutagenic of all compounds tested and showed at least a 250-fold increase in activity when compared to that of its chloroethyl analog, 2-{{{(2-chloroethyl) nitrosoamino}carbonyl}-amino}-2-deoxy-D-glucose (also called chlorozotocin) . All nitrosoureas, with the exception of N'-{(4-amino-2-methyl-5-pyrimidinyl)methyl}-N-(2-chloroethyl)-N-nitrosourea monohydrochloride, a pyrimidine chloroethyl analog, demonstrated an increase in mutagenicity after incubation with induced Sprague-Dawley rat liver microsomes . No correlation between in vitro chemical alkylating activity and mutagenic potential was observed . Mutagenic activity was not observed to be of predictive value for antitumor activity in the L1210 leukemia model system. J Bacteriol, 1980 Jul, 143(1), 78 - 88 Isolation of two protein-free and chemically different lipopolysaccharides from Bordetella pertussis phenol-extracted endotoxin; Le Dur A et al.; Endotoxin prepared from several Bordetella pertussis strains in both immunological phases I and IV gave two lipopolysaccharide peaks (LPS-I and LPS-II) when analyzed on hydroxylapatite columns in a phosphate buffer containing 0.1% sodium dodecyl sulfate; these lipopolysaccharides, present in the ratio of 2:3, are true endotoxins by both chemical and biological criteria . Endotoxins isolated from Escherichia coli, Salmonella typhimurium, and Shigella flexneri gave single lipopolysaccharide peaks when analyzed by the same procedure . Upon hydrolysis with acetic acid (pH 3.4) at 100 degrees C for 1 h, LPS-I released a polysaccharide (PS-I); the linkage broken was that of the glycosidic bond of a non-phosphorylated 3-deoxy-oct-2-ulosonic acid . Treatment with 0.25 M mineral acid at 100 degrees C for 30 min was required to free the polysaccharide moiety (PS-II) of LPS-II, the linkage broken being the glycosidic bond of a phosphorylated 3-deoxy-oct-2-ulosonic acid . Chemical and physical differences of the polysaccharide moieties PS-I and PS-II present in LPS-I and LPS-II have been described previously (25) . By using the technique of 125I labeling, it was shown that the totality of labeled proteins present in the endotoxin extracted from Bordetella pertussis by the phenol-water procedure could be separated from the lipopolysaccharide by column chromatography on hydroxylapatite; it follows that these proteins are not linked by covalent bonds to the lipopolysaccharide. J Bacteriol, 1980 Jul, 143(1), 105 - 11 Glutamine and related analogs regulate guanosine monophosphate reductase in Salmonella typhimurium; Garber BB et al.; The addition of a glutamine analog, 6-diazo-5-oxo-L-norleucine, or an inhibitor of glutamine synthetase, L-methionine-dl-sulfoximine, to the growth media of most Salmonella typhimurium strains resulted in a marked elevation of guanosine monophosphate reductase levels . The elevation caused by either compound required protein synthesis and could be antagonized by exogenous glutamine . In addition, when glutamine auxotrophs were grown in suboptimal concentrations of glutamine, the guanosine monophosphate reductase levels were increased . It is postulated that glutamine or a product of its metabolism may function under normal conditions as a negative regulatory element in the control of guanosine monophosphate reductase and that decreased effective intracellular levels of glutamine result in an increase in the level of the enzyme. J Bacteriol, 1980 Jul, 143(1), 492 - 8 Involvement of ribosomal ribonucleic acid operons in Salmonella typhimurium chromosomal rearrangements; Lehner AF et al.; As part of our efforts to understand factors influencing chromosomal organization and rearrangements, we studied a family of Salmonella typhimurium tandum duplication mutants . We found that the duplications were originally generated by unequal recombination between pairs of similarly oriented ribosomal ribonucleic acid operons (rrn) . This demonstration involved the physical isolation of the duplicated material as circular deoxyribonucleic acid excised from the duplication . The four rrn operons involved embraced the ilv pur D segment of the chromosome and occurred at positions closely analogous to those previously observed for Escherichia coli . The interval between rrnC and rrnA of S . typhimurium was similar in size to that of E . coli (43 versus 39 kilobases), as was the interval between rrnB and rrnE (94 versus 91 kilobases) . The rrnA-to-rrnB interval of S . typhimurium, however, was 155 kilobases, substantially greater than the 126 kilobases observed for E . coli. J Bacteriol, 1980 Jul, 143(1), 120 - 7 Biosynthesis of bacterial glycogen: purification and properties of Salmonella typhimurium LT-2 adenosine diphosphate glucose pyrophosphorylase; Lehmann M et al.; The adenosine diphosphate glucose pyrophosphorylase from a Salmonella typhimurium LT-2 mutant, JP102, derepressed in the glycogen biosynthetic enzymes was purified to homogeneity . The enzyme was found to be identical with the parent wild-type enzyme with respect to regulatory properties, immunological reactivity, and kinetic constants for the allosteric effectors and for the substrate, adenosine triphosphate . The JP102 enzyme was composed of four identical subunits, each with a molecular weight of about 48,000 . This was supported by the findings that (i) gel electrophoresis under denaturing conditions showed only one component; (ii) digestion with carboxypeptidase B released stoichiometric amounts of arginine, and (iii) amino-terminal sequencing showed a single sequence for the first 27 residues . The properties of the purified S . typhimurium enzyme were compared with the properties of the previously purified Escherichia coli B enzyme. Hoppe Seylers Z Physiol Chem, 1980 Jul, 361(7), 1049 - 58 {The mechanism of action of the herbicide N-(phosphonomethyl)glycine: its effect on the growth and the enzymes of aromatic amino acid biosynthesis in Escherichia coli (author's transl)}; Roisch U et al.; N-(Phosphonomethyl) glycine prolongates the lag-phase and inhibits the growth rate of Escherichia coli, Salmonella typhimurium and Pseudomonas aureofaciens . The eucaryotes Saccharomyces cerevisiae and Neurospora crassa are not inhibited . The effect of growth inhibition in an E . coli culture depends on the time of the herbicide addition and no cells showing resistance against it are observed . The inhibitory effect can be overcome completely by a mixture of phenylalanine, tyrosine and tryptophan . N-(Phosphonomethyl)glycine inhibits phospho-2-oxo-3-deoxyheptonate aldolase and 3-dehydroquinate synthase . Both inhibitory effects are removed by addition of CO2 . Chorismate mutase, prephenate dehydratase and prephenate dehydrogenase are not influenced by this herbicide . Anthranilate synthase is also inhibited by N-(phosphonomethyl)glycine . This inhibition is removed by addition of Mg2 . Phospho-2-oxo-3-deoxyheptonate aldoase is derepressed in E . coli cells grown in minimal medium containing N-(phosphonomethyl)glycine . Under these conditions the tyrosine-sensitive isoenyme is much more strongly derepressed than the phenylalanine-sensitive isoenzyme . 3-Dehydroquinate synthase is not affected . Chorismate mutase, prephenate dehydrogenase, prephenate dehydratase, and anthranilate synthase are derepressed, but to a lesser extent. Boll Soc Ital Biol Sper, 1980 Jun 30, 56(12), 1322 - 8 {Use of the D7 strain of S . cerevisiae in the determination of environmental genetic risk . 2 . Genetic effects of procarbazine}; Bronzetti G et al.; Procarbazine was tested in vitro without and with S-10 fraction from mice liver (microsomal assay) using Saccharomyces cerevisiae strain D7, Salmonella typhimurium (strains TA 98, TA 100, TA 1535) and in vivo in Swiss albino mice (host mediated assay) using D7 . Procarbazine without S-10 fraction was highly toxic and induced mitotic cross-over, gene conversion, and reverse mutation in D7 . It had a toxic effect on all the Salmonella strains, but it did not induce any reverse mutations of the histidine mutants . In host-mediated assay using Saccharomyces, there was no genetic effect found in the indicator organism. Biochim Biophys Acta, 1980 Jun 20, 599(1), 1 - 12 In vivo effects of local anesthetics on the production of major outer membrane proteins by Escherichia coli; Pugsley AP et al.; Synthesis of a major outer membrane pore protein (the OmpF protein) by Escherichia coli K-12 was specifically and reversibly inhibited by low doses of procaine and other local anesthetics . The treated cells maintained the same total number of pores in their outer membrane by increased synthesis of the OmpC pore protein . Procaine also inhibited synthesis of the OmpF protein by Salmonella typhimurium and by E . coli B, although in the latter case, some OmpF protein was still detected in the outer membrane of treated cells . Experiments in which transcription was blocked by pretreatment with rifampicin indicated that procaine did not inhibit translation of the stable OmpF mRNA and that there was no pool of preformed OmpF and mRNA in cells grown in the presence of procaine . Procaine did not affect biosynthesis of the lipopolysaccharide core and did not inhibit the association of OmpF protein with the peptidoglycan . These results are discussed in terms of the known effects of procaine on membrane molecular packaging. Biochem J, 1980 Jun 15, 188(3), 867 - 72 The metabolic oxidation of the ethynyl group in 4-ethynylbiphenyl in vitro; Wade A et al.; 1 . The metabolism of 4-ethynylbiphenyl has been studied in vitro with subcellular fractions of normal and induced rat liver, and rat intestinal microflora (caecal contents) . 2 . Oxidation was NADPH-dependent, was inhibited by CO and stimulated by pretreatment with phenobarbitone or 3-methylcholanthrene . 3 . Oxidation of the ethynyl group occurred in washed microsomal preparations, but not significantly in soluble fractions . Oxidation of the ethynyl group by a microsomal fraction preceded aromatic hydroxylation and no metabolites containing the intact ethynyl group were detected . 4 . The major metabolite in liver fractions was biphenyl-4-ylacetic acid . This was the only product produced by a modified Udenfriend system . 5 . Metabolism of 4-ethynylbiphenyl by rat caecal contents under anaerobic conditions produced very small amounts of 4-vinylbiphenyl . 6 . In a modified Ames test with Salmonella typhimurium TA98, 4-ethynylbiphenyl gave a weak positive result that was doubled after 'activation' with an induced rat S9 fraction. J Hyg (Lond), 1980 Jun, 84(3), 479 - 88 The virulence of salmonella strains for chickens: their excretion by infected chickens; Williams Smith H et al.; Inoculated orally, 16 Salmonella typhimurium strains belonging to 12 phage types varied greatly in their ability to kill 1-day-old chickens; variation was noted even between strains of the same phage type . Fourteen strains belonging to 11 food poisoning serotypes other than S . typhimurium were practically non-lethal when examined in this manner . All of them were lethal by the intramuscular route but some were more so than others . Two were more lethal by this route than one of the S . typhimurium strains that was highly lethal when given orally . With age, chickens rapidly became resistant to fatal infection with the food poisoning strains; given orally, a S . typhimurium strain killed 79% of 1-day-old chickens but only 3% of 2-day-old chickens . Of 2 specific poultry pathogenic strains, one, of S . gallinarum, was lethal by oral inoculation to chickens of all ages but the other, of S . pullorum, was only lethal to very young ones . Some salmonella strains, such as those of S . infantis and S . menston, were more efficient at infecting and colonizing the alimentary tract of chickens than were the more virulent S . typhimurium strains, the S . gallinarum and S . pullorum strains and a S . cholerae-suis strain. Carcinogenesis, 1980 Jun, 1(6), 523 - 32 Mutagenicity of nitrosated alpha-amino acid derivatives N-acetyl-N'-nitrosotryptophan and its methyl ester in bacteria; Venitt S et al.; DL-N-acetyl-N'-nitrosotryptophan (I) and its methyl ester (II), readily formed under mild conditions by the reaction of nitrite with N-acetyltryptophan or its methyl ester, are model compounds for the study of the nitrosation of alpha-amino acid side chains, considered relevant to possible role of nitrosation of peptides and proteins in the aetiology of gastrointestinal cancer . Both compounds were assayed for mutagenicity in a series of Escherichia coli WP2 strains (trp- leads to trp+) and in several strains of Salmonella typhimurium (his- leads to his+), in the presence and absence of a post-mitochondrial supernatant (S9) from livers of rats treated with Aroclor 1254 . Compound I was mutagenic to the following E . coli strains: WP2; WP2uvrA; WP2pKM101; WP2-98 and TA 100 . Compound II was consistently less mutagenic than compound I to the E . coli strains, inactive in S . typhimurium TA 98 and TA 100, but more active than I in TA 1535 . Neither compound was detectably mutagenic to E . coli WP2 lexA . Addition of S9 did not enhance the mutagenicity of either compound, and in some cases reduced the mutagenic to any of the E . coli strains tested, and nitrite alone (at pH 7.1) was very feebly mutagenic at doses where molar equivalents of compounds I were markedly active . The rate of decay of compound I in pH 5.9 was closely paralleled by decay of its mutagenicity . These data and the pattern of cytotoxicity and mutagenicity in several DNA-repair mutants of E . coli suggest that both compounds react with DNA to form excisable DNA-adducts which cause mutation by error-prone repair. J Gen Microbiol, 1980 Jun, 118(2), 367 - 76 Mapping of genes determining penicillin-resistance and serum-sensitivity in Salmonella enteritidis; Myers DE et al.; Two presumptive single-step mutants, resistant to penicillin and sensitive to the bactericidal effect of normal human serum, were isolated on penicillin gradient plates from a smooth, penicillin-sensitive, serum-resistant strain of Salmonella enteritidis (O9,12; gal hisEI cys) . The chemical composition of their lipopolysaccharides, their phage-sensitivity patterns, and their serological and cultural properties showed one to be 'part-rough' and the other smooth . Hfr strains with O antigens O4,5,12 or O1,4,5,12 (two Salmonella typhimurium and one S . abony) and one S . enteritidis F', O9,12, were crossed with the S . enterititis O9,12 mutants . The results with the part-rough mutant indicate that its penicillin-resistance, serum-sensitivity and rough phage pattern result from a single mutation between hisEI and the part of the rfb gene cluster determining O specificity, 4 (abequose) or 9 (tyvelose) . Transduction experiments confirmed that the mutation is closely linked to the his operon . This mutation is inferred to cause an incomplete defect in a transferase for galactose, mannose or rhamnose, the smooth sugars common to O4,5,12 and O9,12 . Results from similar crosses to the smooth, serum-sensitive, penicillin-resistant S . enteritidis mutant indicate that its serum-sensitivity is not linked to his . The occasional independent segregation of penicillin-resistance and serum-sensitivity suggests that other loci modify penicillin-resistance. J Environ Pathol Toxicol, 1980 Jun-Jul, 3(5-6), 195 - 206 Cellular effects in microbial tester strains caused by exposure to microwaves or elevated temperatures; Dutta SK et al.; Several tester strains of Salmonella typhimurium, TA-98, TA-100, TA-1535, and TA-1538; Escherichia coli, W3110 (pol A+) and p3438 (pol A-, repair deficient); and Saccharomyces cerevisiae, D3, D4, and D5 were tested for lethal and mutagenic events when exposed to elevated temperatures or to x-band, pulsed microwave radiation at various power densities . When compared to E . coli pol A+ under growing conditions, E . coli pol A- exhibited decreased cell growth when exposed to microwave radiation at power levels at or above 20 mW/cm2 as well as to temperature levels above 42 degrees C . All yeast and other bacterial strains showed cellular lethality at similar microwave intensities and elevated temperatures . When exposed to elevated temperatures in saline, both quiescent yeast and Salmonella strains exhibited lethal events . However, the Salmonella strains tested showed comparatively less induction of genetic events in the quiescent state compared to induction when the cell were actively growing in broth . These results demonstrate that elevated temperatures generated by microwave exposure could produce genetic events in microbial assay systems . If such systems are to be of value in examining the nonthermal genetic potential of microwave radiation, careful control over exposure conditions will be required to eliminate heat-induced genetic events. Zentralbl Bakteriol A, 1980 Jun, 247(1), 64 - 70 Influence of D,L-ureidosuccinic acid dihydrazide on some biological properties of Pseudomonas pseudomallei and of Salmonella typhimurium; Veljanov D et al.; The changes induced in strains of Pseudomonas pseudomallei and Salmonella typhimurium under the action of D.L-ureidosuccinic acid dihydrazide were characterized . A decrease of the speed of multiplication in vitro and of the oxygen consumption was established . The virulence of the strains was reduced and their susceptibility to phagocytosis in vitro was increased. Zentralbl Bakteriol A, 1980 Jun, 247(1), 50 - 63 {Chemical and biological properties of revertants derived from a Salmonella typhimurium Rd1-mutant (author's transl)}; Schlecht S et al.; Two S-form-revertant strains were isolated from a S . typhimurium Rd1 culture on account of their phage resistance . In microbiological and serological (O-agglutination) characterization - as well as in stability tests (agglutination in auramin and saline and heating at 100 degrees C) - the behaviour of the two strains was the same as that of the wild type . The two strains were found to be indistinguishable from the wild type strain also with respect to the chemical composition of their lipopolysaccharides . Thus the amount and proportion of fatty acids and sugar residues as well as the number of repeating units in the O-chain were all identical . In contrast, the isolated revertants were similar to the Rd1 mutant with respect to their auxotrophic markers methionine and tryptophane, to the absence of flagella as well as to the reduced content of cyclopropane fatty acids (C17, C19) . Protein analysis revealed no significant qualitative or quantitative differences between the wild type strain and the two revertants with respect to the major proteins of their outer membranes . The sensitivity of the revertants to crystal violet, erythromycin and rifamycin SV was intermediate between the wild type and the Rd1 mutant . Their temperature maximum in nutrient broth was 43 degrees C, the retardation in growth at this temperature corresponding to that of the Rd1 mutant . At 37 degrees C, however, the growth rate of the revertants was identical to that of the wild-type, while that of the Rd1 mutant was slower . Addition of sodium chloride to the growth medium rendered the temperature dependent behaviour of the mutants and revertants similar to that of the wild type . Studies in NMRI mice revealed that the revertants, also with regard to their virulence, occupy an intermediate position between the mutant and the wild type . Nevertheless their ability to afford protection to Salmonella typhimurium infection following active immunization with acetone killed cells was as high as that of the wild type . The results show that the biologic behaviour of S . typhimurium is determined by the type of lipopolysaccharide it contains but also to a large extent by other cell-wall constituents. Agents Actions, 1980 Jun, 10(3), 287 - 95 Forward mutation in Escherichia coli and gene conversion in Saccharomyces cerevisiae compared quantitatively with reversion in Salmonella typhimurium; Mitchell ID; Forward mutation to c'azetidine carboxylic acid resistance in Escherichia coli WP2 and gene conversion at the tryptophan locus in Saccharomyces cerevisiae D4 were compared with reversion in strains TA98, TA100 and TA1537 of S . typhimurium for sensitivity and range of agents detected . Eight mutagens of known and differing modes of action were used in assays in liquid culture . It was concluded that neither non-specific system could replace all the Salmonella strains in a programme of mutagenicity assays in liquid culture; however, E . coli caca(r) could adequately replace strains TA100 and TA1537, provided that TA98 was retained to detect certain types of frame-shift mutation . Also gene conversion would prove useful in the assay of antibacterial agents. Can J Microbiol, 1980 Jun, 26(6), 671 - 5 Assimilation of selenate and selenite by Salmonella typhimurium; Brown TA et al.; A comparative study of selenate and selenite assimilation by Salmonella typhimurium revealed that selenite was not transported by the sulphate permease . Selenite uptake could be detected both in wild-type cells repressed for sulphate transport and in mutants that lacked a functional sulphate permease . In contrast, selenate was assimilated by the same process as was sulphate; selenate transport was repressed under the same conditions which repressed sulphate uptake and was absent in permeaseless mutants . Selenite transport was absent if cells were glucose starved or treated with either azide or p-chloromercuribenzoate . The pH optimum was between pH 6 and pH 7; transport was most rapid at 36 degrees C . The double reciprocal plot for selenite transport at different substrate concentrations was biphasic: between 10 and 50 microM SeO32(-) the apparent Km was 37.8 microM, and at higher concentrations, 2.87 mM . The transport rate for 0.1 mM SeO32(-) was significantly stimulated by sulphite concentrations up to 5.0 mM, with a maximum at 3.0 mM SO32- . The results establish a selenite transport process, in S . typhimurium, as the initial step of an assimilatory pathway selective for selenium. Mutat Res, 1980 Jun, 78(2), 145 - 50 The mutagenic activity of ethyl N-hydroxycarbamate and its related compounds in Salmonella typhimurium; Koga H et al.; Alkyl N-hydroxycarbamates exhibited weak but significant mutagenic activity for Salmonella typhimurium TA100 . The mutagenic potencies of these N-hydroxycarbamates were ranked thus: ethyl N-hydroxycarbamate greater than propyl N-hydroxycarbamate greater than methyl N-hydroxycarbamate . Acylation of ethyl N-hydroxycarbamate markedly enhanced its mutagenic activity for TA100 . The highest mutagenic activity was observed with ethyl N-benzoyloxycarbamate among these acyl derivatives . Almost all the compounds were mutagenic to all the strains TA1535, TA100, TA98, especially to TA100. Mutat Res, 1980 Jun, 78(2), 137 - 44 Mutagenic activity of swimming-pool water; Honer WG et al.; Swimming pool water, being chlorinated and exposed to trace organics from use was investigated as a possible source of mutagens using the Salmonella/mammalian-microsome test . Procedures previously described for the extraction of trace organics from water using XAD-2 macroreticular resin were modified to allow quantitative extraction of mutagens . These procedures were superior to freeze-drying and solvent-extraction . Using a base-pair histidine mutant, strain TA100, of Salmonella typhimurium significantly mutagenic responses were observed using concentrates from 3 variations of the extraction procedure . Acidified pool-water extracts eluted with ether or acetone were mutagenic, the former enhanced in the presence of the induced microsomal fraction from rat livers . Non-acidified pool-water extracts eluted with acetone were mutagenic without microsomal activation . These results indicate the presence of more than one mutagen in what is likely a complex mixture of organic molecules in swimming-pool water. Mutat Res, 1980 Jun, 78(2), 113 - 9 Mutagenic potency of haloacroleins and related compounds; Rosen JD et al.; 2-Chloroacrolein, the ultimate mutagen, formed on metabolism of the carcinogenc herbicides, diallate and sulfallate, and its 2-bromo-, 2,3-dichloro- and 2,3,3-trichloro- analogs are much more potent mutagens in the Ames Salmonella typhimurium strain TA1U0 assay than any other aldehydes examined previously or in this study . Polymer formation on reaction of deoxyadenosine with the difunctional 2-chloroacrolein probably involves crosslinking via Schiff base formation at the carbonyl group and Michael addition at the doubts bond. Mutat Res, 1980 Jun, 71(1), 25 - 41 Plasmid (pKM101)-mediated Weigle reactivation in Escherichia coli K12 and Salmonella typhimurium LT2: genetic dependence, kinetics of induction, and effect of chloramphenicol; Dobson PP et al.; In Escherichia coli K12 the reactivation of UV-irradiated phage i