Pediatr Cardiol, 1986, 6(5), 279 - 81 Myocardial infarction in a child with Salmonella enterocolitis; Courtemanche DJ et al.; The case history and findings of a seven-month-old North American Indian girl with myocardial infarction following a prolonged febrile seizure associated with Salmonella typhimurium enterocolitis are presented and discussed . This appears to be a unique observation not previously described in the literature. J Toxicol Environ Health, 1986, 18(3), 339 - 46 Biotransformation of 1-nitropyrene to 1-aminopyrene and N-formyl-1-aminopyrene by the human intestinal microbiota; Manning BW et al.; The nitropolycyclic aromatic hydrocarbon 1-nitropyrene (1-NP) is an environmental pollutant, a potent bacterial and mammalian mutagen, and a carcinogen . The metabolism of 1-NP by the human intestinal microbiota was studied using a semicontinuous culture system that simulates the colonic lumen . {3H}-1-Nitropyrene was metabolized by the intestinal microbiota to 1-aminopyrene (1-AP) and N-formyl-1-aminopyrene (FAP) as determined by high-performance liquid chromatography (HPLC) and mass spectrometry . Twenty-four hours after the addition of {3H}-1-NP, the formylated compound and 1-AP accounted for 20 and 80% of the total metabolism, respectively . This percentage increased to 66% for FAP after 24 h following 10 d of chronic exposure to unlabeled 1-NP, suggesting metabolic adaptation to 1-NP by the microbiota . Both 1-AP and FAP have been shown to be nonmutagenic towards Salmonella typhimurium TA98, which indicates that the intestinal microflora may potentially detoxify 1-NP. Crit Rev Toxicol, 1986, 16(4), 307 - 48 Metabolic activation of mutagenic heterocyclic aromatic amines from protein pyrolysates; Kato R; Mutagenic heterocyclic amines are metabolized to mutagens which act directly on Salmonella typhimurium by P-448 forms of cytochrome P-450 . These direct mutagens are N-hydroxylated heterocyclic amines, such as N-hydroxy-Trp-P-1, N-hydroxy-Trp-P-2, N-hydroxy-Glu-P-1, N-hydroxy-Glu-P-2, N-hydroxy-IQ, N-hydroxy-2-amino-alpha-carboline (N-hydroxy-A alpha C), and N-hydroxy-2-amino-3-methyl-alpha-carboline (N-hydroxy-MeA alpha C) . The treatment of rats with polychlorinated biphenyl stimulated N-hydroxylation of heterocyclic amines about 10- to 260-fold depending on the substrates used . The N-hydroxylation activities of purified cytochrome P-448-H and P-448-L were markedly different . P-448-H, which had very low activity for benzo{a} pyrene metabolic activation, showed high N-hydroxylation activity . The activity ratio P-448-H:P-448-L was markedly different depending on the amines used . This ratio was 45, 22, 3, and 0.02, respectively, for Glu-P-1, IQ, Trp-P-2, and benzo{a} pyrene . On the other hand, N-acetylation of the heterocyclic amines was very low . Although marked species differences in the N-acetylation were observed, the activities of the heterocyclic amines were about 1/100 of that of 2-aminofluorene . N-Hydroxy-Trp-P-2 could react directly to DNA, but N-hydroxy-Glu-P-1 could not . Therefore we need to consider the presence of a further activating system in mammalian and bacterial cells . We observed that N-hydroxy-Trp-P-2 was activated by prolyl-t-RNA synthetase, but N-hydroxy-Glu-P-1 was not activated by the same system . In the bacterial cells, both N-hydroxy-Trp-P-2 and N-hydroxy-Glu-P-1 were not activated by prolyl-t-RNA synthetase . However, both hydroxylamines were activated by the acetyl-CoA-dependent mechanism in mammalian and bacterial cells . These results indicated that the O-acetylation is an important pathway for DNA damage by heterocyclic amines in chemical carcinogenesis. J Toxicol Environ Health, 1986, 18(1), 111 - 9 Comparative mutagenicity studies of azo dyes and their reduction products in Salmonella typhimurium; Krishna G et al.; The arabinose-resistant and Ames assay systems of Salmonella typhimurium were used to evaluate the mutagenic potential of azo dyes and their aromatic amine reduction products . Azo dyes, namely direct black 38, direct blue 15, and direct red 2, were mutagenic in the arabinose-resistant and Ames assays with both hamster and rat liver S9 activation . Both assays gave relatively higher mutagenic responses with hamster S9 . Reduction products of these dyes, namely benzidine, o-dianisidine, and o-tolidine, were mutagenic in the Ames assay . Benzidine was weakly mutagenic and o-dianisidine and o-tolidine were nonmutagenic in the arabinose-resistant assay . These results indicate that both arabinose-resistant tester SV50 and Ames tester TA98 were sensitive in detecting mutagenicity of azo dyes . The use of the standard plate protocol with Ames tester TA98 is more efficient than the modified azo dye protocol in detecting mutagenicity of aromatic amine reduction products . Additional modifications in either the standard plate or modified azo dye protocols may improve detection of mutagenicity of these compounds in the arabinose-resistant assay system. Vopr Onkol, 1986, 32(3), 73 - 80 {Mutagenic activity of carcinogens and other chemical agents in Salmonella typhimurium tests}; Khudolei VV et al.; One-hundred and six chemical compounds were tested in Ames test with bacteria Salmonella typhimurium . Eight different strains (mainly, TA98 and TA100) were used . Liver S9 from Aroclor-treated rats was employed for metabolic activation . In group I comprising 51 compounds with sufficient evidence of carcinogenicity for animals, 45 were mutagenic while 6 (urethane, 1,2-dimethylhydrazine, DDT, chlorophorm, 1,4-dioxane and carbon tetrachloride) were not . In group 2 (27 noncarcinogenic compounds), 22 agents failed to exhibit mutagenicity whereas 5 (acrolein, styrene-oxide, acridine orange, I-naphthylamine and dichlormethane) revealed such activity . In groups 1 and 2, the sensitivity was 88.2, specificity--81.5 and predictive value--90% . In group 3 consisting of 28 agents used in chemical, pharmaceutical and food industries but not yet tested for mutagenicity and for the carcinogenicity of which no conclusive data are available, seven appeared to be mutagens (1-aminoanthraquinone, 2-aminoanthraquinone, 1-amino-4-chloranthraquinone, based blue, dinitrochlorbenzene, nitrosodiphenylamine and 2,3,5-trinitronaphthalene). Mol Gen Genet, 1986 Jan, 202(1), 108 - 11 The isolation and mapping of EF-Tu mutations in Salmonella typhimurium; Hughes D; The first isolation of EF-Tu mutations in Salmonella typhimurium is reported . The mutations were isolated by selecting for resistance to the antibiotic mocimycin (= kirromycin) . The mocimycin resistant phenotype is the result of mutations in each of two genes, tufA and tufB . Strains mutant in only one of the two tuf genes are sensitive to mocimycin . The spontaneous mutation rate of each of the two tuf genes to a mocimycin resistant phenotype differs by an order of magnitude . tufA maps at minute 71-72, closely linked to rpsL . tufB maps at minute 88-89, closely linked to rpoB . These map positions correspond to the locations of tufA and tufB in E . coli. J Pediatr Ophthalmol Strabismus, 1986 Jan-Feb, 23(1), 29 - 30 Endophthalmitis due to Salmonella typhimurium; Appel I et al.; A 1-year-old female patient is described who suffered from sepsis and endophthalmitis due to Salmonella typhimurium . This Salmonella species rarely causes septicemic syndrome or focal infection of body organs . As far as we know this is the first case report of endophthalmitis caused by S typhimurium despite its high frequency among Salmonella infections not caused by S typhi. Food Chem Toxicol, 1986 Jan, 24(1), 51 - 4 Inhibitory effects of flavourings on mutagenesis induced by chemicals in bacteria; Ohta T et al.; The antimutagenic potential of twenty-five flavourings was tested against the activity of several kinds of chemical mutagens in Escherichia coli and Salmonella typhimurium . Anisaldehyde, ethylvanillin and vanillin showed marked antimutagenic effects on mutagenesis induced by 4-nitroquinoline 1-oxide, furylfuramide (AF-2), captan or methylglyoxal in E . coli WP2s . However, they were not effective against mutations provoked by 3-amino-1-methyl-5H-pyrido{4,3-b}indole (Trp-P-2) or 2-amino-3-methylimidazo{4,5-f}quinoline (IQ) in S . typhimurium TA98 . Despite the decrease in the number of mutants, a remarkable increase was observed in the survival of mutagen-treated WP2s cells after exposure to these flavourings . We assume that these compounds may act as bio-antimutagens by enhancing an error-free recombinational repair system, because this reactivation of survival was strictly dependent on the recA gene function but not on the lexA and uvrA gene functions. Food Chem Toxicol, 1986 Jan, 24(1), 27 - 31 Identification, occurrence and mutagenicity in Salmonella typhimurium of two synthetic nitroarenes, musk ambrette and musk xylene, in Indian chewing tobacco and betel quid; Nair J et al.; During N-nitrosamine analysis of extracts of betel quid with tobacco and of the saliva of chewers of betel quid with tobacco for N-nitrosamines using a Thermal Energy Analyzer, two unknown compounds were detected . They were identified as synthetic nitro musks, musk ambrette (5-tert-butyl-1,3-dinitro-4-methoxy-2-methylbenzene, CAS No . 83-66-9) and musk xylene, (1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene, CAS No . 81-15-2), by gas chromatography-mass spectrometry and Fourier transform nuclear magnetic resonance spectroscopy . These compounds were detected in several samples of betel quid with tobacco and in perfumed tobacco used for chewing in India in amounts ranging from 0.45-23.5 mg/g wet weight . Musk ambrette was found to be mutagenic in Salmonella typhimurium TA100 requiring metabolic activation by rat-liver postmitochondrial supernatant but musk xylene lacked mutagenicity. Chem Biol Interact, 1986 Jan, 57(1), 97 - 106 Chemical structure and mutagenic activity of aminoimidazoquinolines and aminonaphthimidazoles related to 2-amino-3-methylimidazo{4,5-f}quinoline; Kaiser G et al.; We have synthesized 11 heterocyclic aromatic amines with chemical structures related to that of 2-amino-3-methylimidazo {4,5-f} quinoline (IQ), a potent mutagen occurring in broiled sardines, fried beef and beef extract . The mutagenic activity of these IQ analogs was studied and compared with that of IQ using the Ames test with strain TA98 of Salmonella typhimurium in presence of a metabolic activation system (S9 mix) derived from rat liver . The mutagenic activities of the IQ analogs vary over a million-fold; structure-activity comparisons indicate major contributions of the methyl substitution in the imidazole ring and of the quinoline-N, and significant contributions of methylation of the exocyclic amino group and of the geometry of the entire ring system. Am J Vet Res, 1986 Jan, 47(1), 75 - 83 Studies on the pathogenesis of Salmonella typhimurium and Salmonella choleraesuis var kunzendorf infection in weanling pigs; Reed WM et al.; Twenty-six 4-week-old pigs were randomly allotted to 4 groups: group 1--orally inoculated with Salmonella typhimurium; group 2--orally dosed with S choleraesuis; and groups 3 and 4, with surgically constructed intestinal loops--loops inoculated with either S typhimurium or S choleraesuis . One pig each from groups 1 and 2 was killed at 8, 12, 24, 48, 72, 96, and 120 hours after inoculation . One pig each from groups 3 and 4 was killed at 2, 4, 6, 8, 12, and 24 hours after intestinal loop inoculation . Inoculation of S typhimurium resulted in acute enterocolitis of variable severity, whereas inoculation of S choleraesuis resulted initially in septicemia followed by formation of large necrotic and ulcerative lesions in the colonic mucosa . The most consistent systemic lesion of S choleraesuis infection was interstitial pneumonia and multifocal hepatic necrosis . Salmonella typhimurium and S choleraesuis were ultrastructurally within enterocytes of ligated ileal loops . Intracellular bacteria were morphologically intact, occurred free in the cytoplasm and membrane bound, and caused no detectable cytotoxic effect to the cell . Both S typhimurium and S choleraesuis penetrated the intestinal mucosa and were isolated from mesenteric lymph nodes at 2 hours after inoculation. Mutat Res, 1986 Jan-Feb, 169(1-2), 17 - 22 The bacterial mutagenicity of nitropolychlorinated dibenzo-p-dioxins; Donnelly KC et al.; The bacterial mutagenicity of 2-nitrodibenzo-p-dioxin, a mixture of 2-nitro-7-chloro- and 2-nitro-8-chlorodibenzo-p-dioxin, 7-nitro-2,3-dichloro-, 8-nitro-2,3,7-trichloro-, 2-nitro-1,3,7,8-tetrachloro- and 3-nitro-1,2,4,7,8-pentachlorodibenzo-p-dioxin was determined using Salmonella typhimurium tester strains TA98 and TA100 with and without rat hepatic S9 for metabolic activation . All the nitro-PCDDs exhibited some direct-acting mutagenicity with both tester strains, however, the activity was significantly lowered in the presence of exogenous S9 and the compounds were more mutagenic to tester strain TA98 . The mutagenicity of the nitro-PCDDs was also dependent on structure because there was a marked decrease in activity with increasing chlorine content . Because nitro-PCDDs have recently been identified as incomplete combustion products of municipal waste, this study confirms that this new class of compounds contains some bacterial mutagens. Mol Biol Rep, 1986, 11(1), 43 - 6 Specific binding affinity for DNA of the L phage (Salmonella typhimurium) in extracts of Escherichia coli; Karlovsky P et al.; The repressor gene cII of the L phage was cloned into plasmid pHC624 and expressed in E . coli . Two separate binding affinities for L phage DNA were identified during fractionation of protein extract of that strain . The activity that salts out in low concentration of ammonium sulphate belonged to the repressor, the activity that salts out in high concentrations of (NH4)2SO4 was proved to be of E . coli origin . Binding sites for the two proteins are located on different fragments of the L phage genome. Environ Mutagen, 1986, 8(1), 109 - 17 Bacterial mutagenicity and chemical analysis of polycyclic aromatic hydrocarbons and some nitro derivatives in environmental samples collected in West Germany; Garner RC et al.; Snow and air particulate samples collected in Upper Frankonia, Federal Republic of Germany, have been analyzed for nitro-polycyclic aromatic hydrocarbons (PAH) and PAH content . A novel clean-up technique has been developed enabling interfering organochlorine environmental contaminants to be removed prior to analysis of the hydrocarbons by GC-MS . Mass fragmentation patterns are presented for 1-nitropyrene, 6-nitrobenzo(a)pyrene, 6-nitrochrysene, and 3-nitrofluoranthene . The level of these compounds found in air samples was in the range of 0.2-2.0 ng.m-3 with the exception of 6-nitrobenzo(a)pyrene, which was not detected . This compares with PAH values of between 1 and 6 ng.m-3 . The freshly fallen snow sample collected at the side of a motorway had no detectable PAHs or nitro-PAHs . Parallel studies on the bacterial mutagenicity of the collected air samples using Salmonella typhimurium TA98 and TA100 in the presence and absence of aroclor-induced rat liver "S9" revealed both "direct" and "indirect" activity . Larger numbers of mutants were induced in the presence of S9 than in its absence . The snow sample was devoid of mutagenic activity . These studies show the utility of the biological approach to screen environmental samples prior to expensive and time-consuming chemical analysis. Diagn Microbiol Infect Dis, 1986 Jan, 4(1), 71 - 6 Recurrent salmonella infection with a single strain in the acquired immunodeficiency syndrome . Confirmation by plasmid fingerprinting; Mayer KH et al.; Five weeks before the development of acquired immunodeficiency syndrome (AIDS), a 38-yr-old homosexual man had symptomatic gastroenteritis that resolved without antibiotic treatment . His stool culture was positive for Salmonella typhimurium at that time . The patient subsequently developed Pneumocystis carinii pneumonia and received a 10-day course of intravenous trimethoprim-sulfamethoxazole . He developed salmonella bacteremia 4 months later . The salmonella isolates from the stool and blood were susceptible to trimethoprim-sulfamethoxazole . Comparison of cryptic plasmids showed a pattern identical to the initial salmonella infection, so infection with a new strain did not cause the bacteremia . This finding illustrates the utility of plasmid fingerprinting as a diagnostic tool, and suggests that persons with AIDS, or those at high risk with prodromal symptoms, should receive prompt, effective therapy for nontyphoidal salmonella gastroenteritis. Carcinogenesis, 1986 Jan, 7(1), 65 - 70 Synthesis and mutagenicity of 1-nitro-6-nitrosopyrene and 1-nitro-8-nitrosopyrene, potential intermediates in the metabolic activation of 1,6- and 1,8-dinitropyrene; Fifer EK et al.; 1,6-Dinitropyrene and 1,8-dinitropyrene are environmental contaminants which are mutagenic in bacteria and cultured mammalian cells . Since nitroreduction, and possibly O-acetylation, have been implicated in the metabolic activation of these compounds, the reduced intermediates, 1-nitro-6-nitrosopyrene and 1-nitro-8-nitrosopyrene, were synthesized and their mutagenicity examined in Salmonella typhimurium and Chinese hamster ovary (CHO) cells . Nitration of 1-acetylaminopyrene yielded a mixture of 1-acetylamino-6-nitropyrene and 1-acetylamino-8-nitropyrene, which was separated by flash chromatography . Following deacetylation, the amino-nitropyrenes were oxidized to the desired nitronitrosopyrenes with m-chloroperoxybenzoic acid . Both nitronitrosopyrenes showed similar levels of mutagenicity in S . typhimurium strain TA98 and a nitroreductase-deficient analogue, TA98NR, but much lower activity in the esterificase-deficient strain, TA98/1,8-DNP6, which suggested that reduced metabolites require further activation by O-acetylation . In contrast, the analogous compound, 1-nitrosopyrene, was equally mutagenic in all three strains while its parent compound, 1-nitropyrene, demonstrated a much reduced mutagenicity in strain TA98NR . In CHO cells, 1-nitropyrene was not mutagenic and the dinitropyrenes were only weakly active, while all three nitrosopyrene derivatives were highly mutagenic . These data support the hypothesis that nitrated pyrenes are metabolized to mutagens through nitroreduction . In Salmonella the limiting step in the metabolic activation of 1-nitropyrene appears to be the initial reduction to 1-nitrosopyrene, while with the dinitropyrenes subsequent esterification of the reduced intermediates seems critical . With CHO cells, the initial reduction to nitroso derivatives is the limiting step for all nitropyrenes, and esterification does not appear to occur in the activation sequence. Carcinogenesis, 1986 Jan, 7(1), 59 - 63 Identification and mutagenicity of metabolites of aristolochic acid formed by rat liver; Schmeiser HH et al.; The rat liver 9000 g supernatant mediated metabolism of the carcinogenic aristolochic acid, which consists of aristolochic acid I (AAI) and aristolochic acid II (AAII), was investigated . Under anaerobic conditions the major metabolites were the corresponding aristolactams for both AAI and AAII . In contrast under aerobic conditions AAII was not detectably metabolized and the only metabolite found for AAI was the O-demethylated derivative aristolochic acid Ia (AAIa) . The metabolites were identified by their u.v., mass and n.m.r . spectra and by comparison with reference standards . The mutagenic activities of the three metabolites were determined in Salmonella typhimurium strains TA1537 and TA 100 . The aristolactams were mutagenic in both strains when a metabolizing system was present . These results indicate that AAI or AAII and their aristolactams exert their effect via a common reactive intermediate, probably the corresponding hydroxylamine . AAIa was only very weakly mutagenic and this metabolite may therefore not be regarded as a major mutagenic metabolite of AAI . These findings suggest that the acids are preferentially metabolized by two totally different pathways in vitro, namely an oxidative pathway for AAI and a reductive pathway for AAII. Carcinogenesis, 1986 Jan, 7(1), 105 - 10 Identification of the DNA adduct formed by metabolism of 1,8-dinitropyrene in Salmonella typhimurium; Andrews PJ et al.; The incubation of {3H}1,8-dinitropyrene with Salmonella typhimurium TA98NR followed by isolation of the DNA from these cells, hydrolysis of the DNA to nucleosides, butanol extraction of the hydrolysate and purification by reversed-phase liquid chromatography afforded a single product . Calf thymus DNA, after treatment with N-hydroxyl-1-amino-8-nitro-pyrene, was hydrolyzed, extracted and purified in a similar fashion to give a single compound which was shown to be the deoxyguanosine derivative 1-N-(2'-deoxyguanosin-8-yl)-amino-8-nitropyrene by a combination of proton n.m.r . and u.v.-vis . spectroscopy and fast atom bombardment mass spectrometry . The DNA adducts formed in vivo and in vitro exhibited identical chromatographic and chemical behavior . Under acidic or basic conditions in the vivo and in vitro adducts were converted to identical products . Reduction of the adduct gave a new, highly fluorescent product that had a fluorescence emission spectrum identical to that of 1,8-diaminopyrene. Cancer Lett, 1986 Jan, 30(1), 103 - 11 Mutagenicity and DNA-excision repair induced by isoniazid after metabolic activation by isolated human and rat hepatocytes; Neis JM et al.; The mutagenic potency of isoniazid (INH) (a widely used antitubercular drug) towards Salmonella typhimurium strain hisG46 was studied in the Salmonella/hepatocyte suspension-assay, comprising isolated human or rat hepatocytes as metabolic system . The potency of INH to induce DNA-excision repair in these hepatocytes was also measured . With rat hepatocytes, INH appeared to be only weakly mutagenic and did not induce significant increases in hepatocellular DNA-excision repair . With isolated hepatocytes of two human subjects, INH appeared also only weakly mutagenic . However, with hepatocytes of two other human subjects, INH was found to be highly mutagenic . Comparable results were obtained for the induction of hepatocellular DNA-excision repair. Mutat Res, 1986 Jan, 173(1), 9 - 11 Influence of retinoids on the mutagenicity of cigarette-smoke condensate in Salmonella typhimurium TA98; Wilmer JW et al.; The effects of 3 different retinoids (all-trans-retinol, all-trans-retinoic acid, and all-trans-retinyl acetate) on the mutagenic activity of cigarette-smoke condensate were investigated in Salmonella typhimurium TA98 . Neither an enhancing nor an inhibitory effect of the retinoids on the mutagnicity of cigarette-smoke condensate was observed. Mutat Res, 1986 Jan-Feb, 159(1-2), 1 - 11 Mutations in Salmonella typhimurium recovered from livers and spleens of mice; Wright AE et al.; Balb/c mice were inoculated intraperitoneally with TA2662, a smooth derivative of the Salmonella typhimurium Ames tester strain (TA102) which carries the mutable hisG locus on a multicopy plasmid, or TA103, which carries the same hisG gene on the chromosome . The bacteria were recovered at various times from the livers and spleens of the infected mice . Total numbers of bacteria were determined and the mutant frequency was estimated . The frequency of occurrence of histidine prototrophs in experiments using TA2662 was substantially above the frequency found with this strain grown in vitro . The mutant frequencies in experiments using TA103 recovered from mice were also highly significantly increased above background . We did not identify factors which might suggest selection in vivo for histidine prototrophs . There is sufficient histidine in body fluids of the host for the growth of His- bacteria . The His- and His+ derivatives were found to grow equally well in vitro in the presence of amounts of histidine approximating concentrations known to exist in vivo . It is probable that mutations in TA2662 are greatly underestimated, since the hisG-containing plasmid is lost at relatively high frequency during incubation in a variety of conditions. J Med Chem, 1986 Jan, 29(1), 40 - 4 Quantitative structure-activity relationship of the mutagenicity of substituted N-nitroso-N-benzylmethylamines: possible implications for carcinogenicity; Singer GM et al.; The relative mutagenicities of substituted N-nitroso-N-benzylmethylamines have been reexamined from a quantitative structure-activity relationship point of view . Most of the compounds were mutagenic toward Salmonella typhimurium TA 1535 with Aroclor-induced male hamster liver S9 activation . The dose-response data were subjected to a multiple linear regression equation calculated in a stepwise manner, which found that the differences in mutagenicities could be explained primarily by differences in the three-bond path molecular connectivity index, with smaller contributions from sigma and pi . Moreover, a polynomial regression analysis showed that the maximum mutagenicity could be explained by an optimal amount of electron withdrawal by the substituent which would cause a weakening, or activation, of the methylene C-H bond . The possible relevance of these observations to carcinogenesis is discussed. Mutagenesis, 1986 Jan, 1(1), 35 - 9 Structure-activity relationships in the mutagenicity of N-substituted derivatives of phenanthrene-9,10-imine; Stark AA et al.; A series of K-region, N-substituted phenanthrene imines were tested for mutagenicity in Salmonella typhimurium TA100 . All chemicals were mutagenic in the absence of an exogenous metabolic activation system . The apparent decay times of the mutagenic species in diffusion plates and their alkylating activities were also measured . The unsubstituted phenanthrene-9,10-imine was approximately 70-fold more mutagenic than the corresponding phenanthrene-9,10-oxide . N-substitution with electron-releasing groups resulted in chemicals that were more mutagenic than those substituted with electron-withdrawing groups . The mutagenic activity of the latter group of chemicals was comparable with that of phenanthrene-9,10-oxide . Except for N-chlorophenanthrene imine, both alkylation of p-nitrothiophenol and apparent decay times in diffusion plates were inversely correlated with mutagenicity . It is hypothesized that reactivity towards p-nitrothiophenol (alkylating activity) and mutagenicity reflect different reactions, in contrast to other chemical mutagens . The results suggest that the high potency of phenanthrene imines as mutagens is possibly due to DNA binding via an aziridinium ion rather than a carbonium ion. C R Acad Sci III, 1986, 302(17), 625 - 8 {Metabolic activation of benzo(a)pyrene by human amniotic fluid}; Daubeze M et al.; The in vitro activation of benzo(a)pyrene was studied in amniotic fluid from ten 4-month pregnant women . Benzo(a)pyrene monooxygenase and epoxide hydrolase activities were in the same range in amniotic fluid as in human liver . Glutathione epoxide transferase activity was markedly lower than in hepatocytes . Human amniotic fluid also catalyzed the formation of hydrocarbon metabolites mutagenic to Salmonella typhimurium TA98 (Ames system) . Profiles of amniotic fluid aromatic hydrocarbons from non smokers exhibited low benzo(a)pyrene concentration (less than 0.1 ng/ml). Microbios, 1986, 46(186), 15 - 20 Influence of caffeine on mitomycin C induced mutagenesis; Kim J et al.; Caffeine significantly repressed MMC induced reversion of Salmonella typhimurium strain TA92 from his- to his+ . The addition of MMC (0.5 micrograms/ml) to broth cultures resulted in a slightly decreased growth rate, as measured turbidimetrically, along with a linear decline in CFU of 1 log cycle in 7 h . The addition of caffeine (0.33 mg/ml) plus MMC (0.5 micrograms/ml) resulted in cessation of growth and a decrease in culture turbidity after two generations of growth which was accompanied by a linear decline in CFU of four log cycles in 7 h . The repression of MMC induced mutagenesis by caffeine is therefore most probably due to interference with an error-prone repair process which results in the destruction of cells with damaged DNA. Plasmid, 1986 Jan, 15(1), 48 - 56 Genetic analysis of insertion mutations of the promiscuous IncP-1 plasmid R18 mapping near oriT which affect its host range; Schilf W et al.; Transposon Tn7 insertion mutations of the promiscuous IncP-1 plasmid R18 which affect its conjugational transmissibility from Pseudomonas aeruginosa to Escherichia coli C, a strain of E . coli K12, Salmonella typhimurium and P . maltophilia have been mapped physically . They map to coordinate 53.5 kb in the Tral region of the plasmid . An 800-bp fragment mapping between R18 coordinates 52.85 and 53.65 kb, which complemented the host range defect of the mutants when tested with E . coli C as recipient, has been identified . However, complementation occurred only when the 800-bp cloned fragment was provided in the E . coli C recipient but not when situated in the P . aeruginosa donor . It is concluded that a trans-acting gene product of R18 is required, in the transcipient, for conjugative DNA metabolism during, or immediately following, the conjugational transfer of this plasmid between certain donor and recipient hosts. J Med, 1986, 17(5-6), 285 - 97 Effect of Salmonella typhimurium porins on the cardiovascular and renal apparatus; Galdiero F et al.; The cardiovascular effects of porins were evaluated using porins isolated from Salmonella typhimurium SH5014 . In dogs porins depress arterial systemic pressure, vasomotor reactivity of norepinephrine and peripheral vagal stimulation . They are capable of modifying the sinocarotidal baroreceptor reactivity . In mice porins increase the cardiotoxic effects of isoprenaline, thyroxine, emetine and of p-nitrophenol . In rats porins increase the arrhythmogenic and lethal effects of BaCl2 and also give rise to renal lesions, probably at the tubular level. Gene, 1986, 46(1), 57 - 64 Plasmids allowing transcription of cloned DNA by Salmonella typhimurium phage SP6 RNA polymerase to produce RNAs with authentic 5'-terminal sequences; Nam HG et al.; We wished to determine whether there is any specific sequence downstream of the start point of the SP6 promoter which is required for its function in the plasmid pSP64 (Melton et al., 1984) . Lack of such specificity would permit in vitro synthesis of an RNA molecule having a 5'-terminal sequence identical to its wild-type in vivo counterpart . To test its requirement, we replaced all of the SP6 sequence downstream of the transcription start point with heterologous nucleotides (nt) and found that any sequence will suffice to permit efficient and accurate transcription . These results permitted construction of plasmids for synthesis of 'authentic' transcripts from cloned DNA . In one case, by an oligodeoxynucleotide-mediated site-specific deletion, we placed the start point of yeast gene TCM1 at nt + 2 of the SP6 promoter and produced in vitro TCM1 mRNA with a wild-type 5'-terminal sequence . We also constructed a vector, pSP64 delta 1, in which the SalI/AccI/HincII recognition sites of pSP64 reside at nt + 2 through + 7 . Plasmids such as pSP64 delta 1 may be more useful in some cases as insertion of any DNA fragment at one of these three sites will yield a transcript in which only two to four nt are derived from the vector. Gene, 1986, 46(1), 113 - 21 Mutations resulting in promoter-like sequences which enhance the expression of araC in Salmonella typhimurium; Lee JH et al.; The araC gene in Salmonella typhimurium is autogeneously regulated . Nine non-self-regulated mutants were isolated by selecting for increased expression of an araC-lacZ fusion in the presence of a repressing AraC protein . S1 mapping experiments demonstrated that the effect of the mutations was to increase the amount of araC mRNA in the cell . The 5'-end of the major araC transcript was the same in the wild-type (wt) and mutant strains . DNA sequence analysis showed that all nine mutations occurred in the araC promoter . Two mutations were a G-to-T transversion at position -25, six were a G-to-T transversion at position -47 and one was a single bp deletion at position -83 . The data suggest that the mutations have created a new RNA polymerase binding site which enhances transcription from the wt start point. Gene, 1986, 46(1), 1 - 11 Reconstitution of an operon from overlapping fragments: use of the lambda SV2 integrative cloning system; Gaitanaris GA et al.; We have used the lambda SV2 system {Howard and Gottesman . In Gluzman (Ed.), Eukaryotic Viral Vectors . Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 1982, pp . 211-216; in Inouye, M . (Ed.) Experimental Manipulations of Gene Expression . Academic Press, New York, 1983, pp . 137-153} to reconstitute the Salmonella typhimurium his operon from overlapping fragments . lambda SV2 can be propagated as an autonomously replicating plasmid or as a prophage integrated in the Escherichia coli chromosome at the lambda attachment site; our reconstitution was accomplished in the integrated state . We first inserted a portion of the his operon into lambda SV2 and integrated the resulting plasmid by site-specific recombination into the E . coli chromosome . This was achieved by brief induction of a resident prophage . The lysogen was then transformed with DNA from a lambda SV2 clone carrying the remainder of the his operon on an overlapping DNA fragment . The second plasmid was forced to integrate into the first by homologous recombination . When this recombination occurs at the his overlap, a lysogen carrying two lambda SV2 prophages is produced . One prophage carries the entire his operon and the other carries the his overlap region . The latter is removed by site-specific recombination, permitting further contiguous sequences to be sequentially added to the remaining prophage . This method should be applicable for the reconstitution and maintenance of large genes or gene clusters in the E . coli genome. Folia Microbiol (Praha), 1986, 31(5), 353 - 62 Integration of transposon Tn10 into phage L (Salmonella typhimurium); Spanova A et al.; Transposon Tn10 was transposed into phage L (Salmonella typhimurium) from F'ts114lac+zzf::Tn10 plasmid of strain TT629 (Chumely et al . 1979) . Phage L with the insertion Tn10 (L::Tn10-8) was isolated in the form of a prophage in the lysogenic strain S . typhimurium LT2-18 (L::Tn10-8), in which it can be induced with UV light . The phage induced in this way is defective; however, it forms plaques at a multiplicity of infection (moi) greater than one and transduces the tetracycline-resistance determinant to tetracycline-sensitive cells . Analysis of its DNA by restriction endodeoxyribonucleases revealed insertion of the intact transposon Tn10 of 9300 bp in the E fragment, formed during the action of EcoRI, at a distance of 16,800 bp from the pac site. Gene, 1986, 45(1), 51 - 7 Identification and nucleotide sequence of the activator gene of the externally induced phosphoglycerate transport system of Salmonella typhimurium; Yu GQ et al.; A recent study from this laboratory (G-q . Yu, D . Goldrick, H.R . Kaback and J-s . Hong, in preparation) indicates that the externally induced phosphoglycerate transport system (pgt) of Salmonella typhimurium is positively regulated by the activator gene, pgtA, and that the pgtA is localized in the SalI-PstI restriction fragment 3.0 kb from the permease gene, pgtP . In this paper, we describe the identification of the activator gene and its gene product and the determination of the complete nucleotide (nt) sequence of the activator gene as well as of a downstream gene not required for pgtP expression . The amino acid sequence of the activator based on the nt sequence shows an N-terminal signal-like sequence which is apparently not cleaved and three potential transmembrane sequences in the C-terminal half of the protein based on the hydropathy analysis. Gene, 1986, 44(2-3), 211 - 7 The metH gene from Salmonella typhimurium LT2: cloning and initial characterization; Urbanowski ML et al.; A 19-kb EcoRI DNA fragment carrying the metH gene of Salmonella typhimurium LT2 was cloned into plasmid vector pACYC184 and propagated in Escherichia coli K-12 . The size of the metH gene product was observed to be approx . 120 kDa, as determined by SDS-polyacrylamide gel analysis of plasmid-specific polypeptides synthesized in a minicell system . The direction of transcription of the metH gene relative to the cloned fragment was determined, and the positions of translation initiation and termination were estimated. J Cancer Res Clin Oncol, 1986, 111(2), 149 - 53 Biological activity of N-nitrosodiethanolamine and of potential metabolites which may arise after activation by alcohol dehydrogenase in Salmonella typhimurium, in mammalian cells, and in vivo; Denkel E et al.; The potent carcinogen N-nitrosodiethanolamine (NDELA) which is nonmutagenic in standard modifications of the S . typhimurium/mammalian microsome assay, can be activated effectively by alcohol dehydrogenase/NAD (ADH/NAD) to intermediates which are directly mutagenic in strains TA 98 and TA 100 . The expected metabolites N-nitroso-2-hydroxymorpholine (NHMor), N-nitroso-(2-hydroxyethyl)-glycine (NHEG), N-nitrosoiminodiacetic acid (NIDA), and glycolaldehyde were assayed for their direct mutagenic activities in S . typhimurium TA 1535, TA 98, and TA 100 . All compounds were clearly mutagenic in TA 100, but different specificities were observed for the other strains . NDELA and its putative mutagenic metabolites were also tested for induction of genotoxic activities by determination of DNA single strand breaks in primary rat hepatocytes . In these cells, NDELA and NHMor were clearly genotoxic, whereas NHEG and NIDA were inactive . In contrast, when assayed for the induction of selective DNA amplification NDELA and its metabolites were not found to induce SV40 DNA synthesis in SV40-transformed Chinese Hamster cells . The compounds were also assayed for induction of DNA single strand breaks in the liver after a single oral application to rats . NDELA and NHMor were about equally active in this in vivo test, whereas NHEG, NIDA and glycolaldehyde were inactive . Differences in biological activity in the cultivated cells, as compared to hepatocytes or to the in vivo situation may most probably be due to differences in metabolism and/or pharmacokinetics. J Cancer Res Clin Oncol, 1986, 111(2), 115 - 22 Use of diethyldithiocarbamate as a probe to detect stable intermediates during the decomposition of several mutagenic and nonmutagenic N-nitroso compounds; Wiessler M et al.; By showing that methyldiethyldithiocarbamate is formed from the reaction of methylnitrosourea and disulfiram, we demonstrated in previous experiments that one of the anticarcinogenic/antimutagenic mechanisms of disulfiram is the scavenging of reactive species . We propose that this reaction may be employed additionally as a model for elucidating the following: (a) possible reactions between alkylating species and nucleophilic sites within the cell, and (b) the existence of stable intermediates during the metabolism of N-nitroso compounds . With structurally related pairs of nitrosoureas (n-propyl/isopropyl; cyclopropyl/allyl; 2-phenylethyl/l-phenylethyl), for which each alkylating group of the first compound can spontaneously rearrange to form the alkylating group of the second isomer, we investigated whether the alkylation proceeds via a monomolecular (sn1) or a bimolecular substitution (sn2) . For this, we comparatively determined the relative mutagenic activities of each isomer in Salmonella typhimurium TA 1535, as well as their reactivities towards diethyldithiocarbamate (DDTC) by identifying the reaction products . These studies were aimed at revealing the possible formation of a free carbonium ion in the decomposition of several nitrosoureas in the rat liver supernatant fraction . Our system showed that DDTC reacts by two competing mechanisms: attack at the diazonium ion and at the free carbonium ion . Therefore the striking differences which were observed in the mutagenic potency of cyclopropylnitrosourea and N-nitrosoallylurea as well as of N-nitroso-2-phenylethylurea and N-nitroso-1-phenylethylurea cannot be explained only by the different electrophilic reactivities of the respective intermediates. Mol Gen Genet, 1986 Jan, 202(1), 42 - 7 Gene structure in the histidine operon of Escherichia coli . Identification and nucleotide sequence of the hisB gene; Chiariotti L et al.; The bifunctional enzyme imidazoleglycerolphosphate dehydratase and histidinolphosphate phosphatase is encoded by the hisB gene . The fourth gene of the histidine operon, hisB, was cloned and mapped on a 2,300 base pair DNA fragment . In the present study we report the complete nucleotide sequence of the hisB gene of Escherichia coli . The gene is 1,068 nucleotides long and codes for a protein of 355 amino acids with an apparent molecular weight of 39,998 daltons . The protein product(s) of the hisB region of both Salmonella typhimurium and E . coli were identified by subcloning and expression in an in vitro translation system . In both organisms the hisB gene directed the synthesis of a single protein with an apparent molecular weight of 40,500 daltons, consistent with the data derived from the nucleotide sequence analysis. J Bacteriol, 1986 Jan, 165(1), 276 - 82 Identification of the tip-encoded receptor in bacterial sensing; Russo AF et al.; A chemotaxis gene encoding a protein with receptorlike properties has been identified in Salmonella typhimurium and termed tip for taxis-involved protein . Based on the stringency of DNA hybridization, the tip gene has about 75% homology with a region of the tar gene encoding the cytoplasmic domain of the aspartate receptor . Introduction of the tip gene into a smooth-swimming Escherichia coli receptor mutant (tar tsr tap) restored both chemotaxis ability on soft-agar-tryptone plates and a wild-type swimming phenotype . We have shown, by overexpressing the CheY protein, that shifting of the mutant swimming bias in the absence of receptors is insufficient to restore chemotaxis ability . This suggests that in addition to resetting the swimming bias, the tip gene product functions as a receptor . By functional criteria, we found that Tip is not a duplicate aspartate (Tar) or serine (Tsr) receptor gene . Based on behavioral properties, the S . typhimurium Tip receptor provides functional features similar to those of the E . coli Tap receptor. J Bacteriol, 1986 Jan, 165(1), 193 - 7 Isolation and characterization of lon mutants in Salmonella typhimurium; Downs D et al.; In this paper we report the isolation and characterization of lon mutants in Salmonella typhimurium . The mutants were isolated by using positive selection by chlorpromazine resistance . The physiological and biochemical properties of the lon mutants in S . typhimurium are very similar to those of Escherichia coli lon mutants . Mutants altered at this locus contain little or no activity of the ATP-dependent protease La and show a number of pleiotropic phenotypes, including increased production of capsular polysaccharides, increased sensitivity to UV light and other DNA-damaging agents, and a decreased ability to degrade abnormal proteins. J Basic Microbiol, 1986, 26(2), 113 - 6 {Excretion of 2,3-dihydroxybenzoic acid by an enterobactin-negative multiresistant wild strain of Salmonella typhimurium}; Rabsch W et al.; In investigations of iron siderophores produced by different Salmonella typhimurium strains we found a strain deficient in enterobactin production . Using microbiological and chemical methods, we detected the production and excretion of 2,3-dihydrobenzoic acid, a metabolite of the enterobactin biosynthesis pathway . The strain was able to produce aerobactin . We suggest that the iron uptake of pathogenic strains can be mediated by aerobactin alone . For a correct enterobactin bioassay it is necessary to use a mutant unable to grow on 2,3-dihydroxybenzoic acid. Teratog Carcinog Mutagen, 1986, 6(6), 511 - 9 The direct-acting mutagenicity of nitroimidazo{2,1-b}thiazoles in Salmonella typhimurium; Hrelia P et al.; A series of nitroimidazo{2,1-b}thiazole derivatives was investigated for direct-acting mutagenic potency with the Salmonella assay . All of the nine derivatives tested were mutagenic . The compounds induced predominantly base displacements resulting in frame-shift mutations . The mutagenic activity did not require the S9 fraction but was largely dependent on "classical" bacterial nitroreductase . The primary basis of the mutagenic activity of nitroimidazo{2,1-b}thiazoles appears to be a reduction of the nitro-function to the corresponding hydroxylamine . Mutagenicity seems to be paralleled by an increase of the nitro groups: dinitroderivatives were more active than nitroderivatives . Other electrophiles and sterically constrained nitro groups could account for differences in genotoxicity. Gene, 1986, 46(2-3), 297 - 300 Sequence of glutamine synthetase from Salmonella typhimurium and implications for the protein structure; Janson CA et al.; To aid in the interpretation of the 3.5 A resolution electron density map of glutamine synthetase (GS) from Salmonella typhimurium, the nucleotide sequence of the gene coding for this enzyme has been determined . The predicted sequence of 468 amino acids (Mr = 51,628) has been compared to the sequence and sequence fragments reported by others for GS of Anabaena and Escherichia coli . The homology between the pairs of sequences is sufficiently strong to suggest that the overall three-dimensional structures of the three GS are similar . The predicted positions of alpha helices are in moderately good agreement with the electron-density map. Comp Biochem Physiol C, 1986, 85(1), 111 - 4 Selective activation of carcinogenic aromatic amines to bacterial mutagens in the marine mussel Mytilus galloprovincialis; Britvic S et al.; The postmitochondrial fraction of the marine mussel Mytilus galloprovincialis digestive gland activates selectively precarcinogenic aromatic amines, but not precarcinogenic benzo{a}pyrene, to Salmonella typhimurium TA 98 mutagens . This activation potential is NADPH-dependent, is not inducible by exposure to Diesel 2 oil and a polluted environment, and is inhibited by methimazole . The characteristics of this activation potential are consistent with the recent finding of the presence of FAD-containing-, and lack of cytochrome P-450 dependent-, monooxygenase activity in Mytilus edulis . The presence of such selective potential in marine invertebrate(s) may bring new insight into our understanding of the fate and the effects of carcinogens in the marine environment. Teratog Carcinog Mutagen, 1986, 6(4), 275 - 87 Sublethal pH decrease may cause genetic damage to eukaryotic cell: a study on sea urchins and Salmonella typhimurium; Cipollaro M et al.; Further evidence is reported here of genetic and developmental damage that can be induced by a sublethal pH decrease . The effects of three inorganic acids (HCl, H2SO4, and H3PO4) on embryos and sperm from the sea urchins Sphaerechinus granularis and Paracentrotus lividus were evaluated . In addition, acidification of the medium was tested for spontaneous reversion to His+ prototrophy in Salmonella typhimurium (strains TA97, TA98, TA100, TA102, TA1535) up to toxic levels, by both liquid incubation and agar plate incorporation . The induction of developmental and mitotic abnormalities in S . granularis confirmed our previous observations on P . lividus . Embryotoxicity was exerted in S . granularis more severely by H3PO4 than by HCl or H2SO4 (pH 7 to 6), while the induction of mitotic abnormalities appeared at a pH of less than or equal to 6.5 irrespective of the acids used . By suspending S . granularis or P . lividus sperm in acidified filtered seawater (fsw) and then inseminating the eggs in natural fsw (pH = 8.0), the offspring showed developmental and mitotic abnormalities . Low-pH-induced spermiotoxicity was ruled out in our experiments, since fertilization success of acid-exposed sperm was actually enhanced, as compared to sperm suspended in untreated fsw . The exposure of S . typhimurium to different pH's (ranging from 4 to 9) invariably failed to induce any changes in reversion rates, regardless of the acids (or alkali) being used . These results suggest that extracellular acidification may cause sublethal damage that in turn leads to an impairment of mitotic activity and cell differentiation. Teratog Carcinog Mutagen, 1986, 6(3), 219 - 35 Mutagenic and cytotoxic potencies of a series of anthracycline derivatives as measured by His+ reversion, 8-azaguanine resistance and direct plating cytotoxicity tests in Salmonella typhimurium; Thomas HF; His+ reversion at multiple his- loci, 8-azaguanine resistance, and a previously reported direct plating cytotoxicity test were used to measure the genotoxic potencies of a series of anthracycline derivatives in Salmonella typhimurium . N-demethylated amino sugar monosaccharide anthracyclines reverted most his- tester strains and were positive with 8-azaguanine selection . Reversion of strain TA98 was the most sensitive end point for measuring the mutagenic activity of the N-demethylated anthracyclines . N,N-dimethyl amino sugar derivatives of Adriamycin and daunomycin were negative as measured by His+ reversion in tester strain TA98, but generated positive responses in tester strain TA102 that were equal to or greater than those of the demethylated parent compounds . Similarly, N,N-dimethyl amino sugar derivatives of pyrromycinone and 1-deoxypyrromycinone had no mutagenic activity as measured by His+ reversion except in tester strains TA102 and TA104 . These later compounds also gave positive responses with 8-azaguanine selection . In view of these results, the importance of amino sugar dialkylation and anthracycline mechanisms of mutagenesis are discussed. IARC Sci Publ, 1986, (77), 267 - 76 Biotransformation and toxicity of lindane and its metabolite hexachlorobenzene in mammals; Gopalaswamy UV et al.; Lindane (gamma-hexachlorocyclohexane) is an important organochlorine pesticide used extensively for agricultural and public health purposes in India and in other developing countries . Because of its relative chemical stability and lipid solubility, it is known to enter food chains . This study was carried out in order to identify the metabolic capacity of rat-liver enzymes to transform lindane . It has been observed that lindane is made aromatic in this animal, yielding hexachlorobenzene (HCB) both in vivo and in vitro . Following the incubation of liver slices with U-14C-lindane, a significant amount of radioactivity was found to be incorporated into HCB . Although it has been reported earlier that detoxification of the pesticide occurs through dehydrochlorination reactions in mammalian species, the direct aromatization of lindane to HCB is a novel pathway and may have implications for the safety of this pesticide, since several studies have reported that HCB is carcinogenic in experimental animals . In view of the reported correlation between carcinogenicity and mutagenicity, both lindane and HCB have been tested for possible mutagenicity using the Salmonella typhimurium test system . The mutagenic response was found to be variable in different experiments. Microbiol Immunol, 1986, 30(9), 893 - 901 Stimulation of macrophages and antitumor activity of radiodetoxified endotoxin; Nerkar DP et al.; Lipopolysaccharide of Salmonella typhimurium was irradiated with gamma radiation at 10, 15, and 30 kGy doses . A dose of 30 kGy significantly detoxified the LPS (180 times) . Mice were injected intraperitoneally with the radiodetoxified LPS, and it was found that it stimulated peritoneal macrophages as was evident from the enhancement of their acid hydrolases and cellular RNA content . Both LPS and radiodetoxified LPS exhibited antitumor activity against S180 cells in Swiss mice . Treatment with 20 micrograms/mouse of either LPS or 30 kGy LPS gave maximum survival of the mice (90%) . These mice were found to resist the challenge of S180 cells (1 X 10(6)). Chem Biol Interact, 1985 Dec 31, 56(2-3), 145 - 55 Inverse correlation between bacterial frameshift mutagenicity and yeast mitochondrial effects of antitumour anilinoacridines; Baguley BC et al.; The mutagenicity of a series of derivatives of 9-anilinoacridine, including the clinical antitumour agent amsacrine, has been assessed using a bacterial frameshift tester strain (Salmonella typhimurium TA1537) and a yeast petite colony assay (Saccharomyces cerevisiae 5178B) . The results have been compared with microbial mammalian cell cytotoxicity, DNA binding affinity and acridine base strength (pKa) . Compounds containing strong electron donor substituents on the acridine ring, and which have a high acridine pKa, show minimal frameshift mutagenicity but are strong inducers of petite yeast mutants . Conversely, some compounds which have a high DNA binding constant but a significant proportion of uncharged form at neutral pH, show high frameshift mutagenicity but minimal induction of petite mutants . It is hypothesised that this inverse relationship arises from the presence of trans-membrane drug transport mechanisms which act to exclude some compounds, particularly strongly basic compounds from the cytoplasm and to concentrate them in mitochondria. J Biol Chem, 1985 Dec 25, 260(30), 16089 - 98 Location of polar substituents and fatty acyl chains on lipid A precursors from a 3-deoxy-D-manno-octulosonic acid-deficient mutant of Salmonella typhimurium . Studies by 1H, 13C, and 31P nuclear magnetic resonance; Strain SM et al.; Eight anionic disaccharide precursors of lipid A accumulate at 42 degrees C in 3-deoxy-D-manno-octulosonic acid-deficient temperature-sensitive mutants of Salmonella typhimurium . These compounds comprise a series of lipids based on the minimal structure, O-{2-amino-2-deoxy-N2,O3-bis(3-hydroxytetradecanoyl)-beta-D-glucopyranos yl} -(1----6)-2-amino-2-deoxy-N2, O3-bis(3-hydroxytetradecanoyl)-alpha-D-glucopyranose 1,4'- bisphosphate (designated lipid IVA) that differ from each other by the presence of an additional phosphoethanolamine moiety (IIIA), or an aminodeoxypentose moiety (IIA), or both (IA) . A homologous set of metabolites is further derivatized with a palmitoyl function; these are designated IVB, IIIB, IIB, and IB (Raetz, C . R . H., Purcell, S., Meyer, M . V., Qureshi, N., and Takayama, K . (1985) J . Biol . Chem . 260, 16080-16088) . The attachment of the palmitoyl moiety, known to be on the reducing terminal GlcN residue by mass spectrometry, was determined to be O-beta of the N2-linked beta-hydroxymyristoyl group of that residue of IVB by 13C NMR and two-dimensional 1H chemical shift correlation spectroscopy experiments . 31P NMR indicated the presence of diphosphodiester moieties in IIIA, IIIB, and IA and monophosphodiester moieties in IIA and IA . Selective 1H decoupling of the 31P spectrum of IIIA demonstrated that the O-diphosphoethanolamine moiety is attached to the O4' position in IIIA . On the basis of the observed 31P chemical shifts it was concluded that the aminodeoxypentose is located at position 1 in IIA and IA, while diphosphoethanolamine is most likely located at O-4' in IA and IIIB, as in IIIA. J Biol Chem, 1985 Dec 25, 260(30), 16080 - 8 Isolation and characterization of eight lipid A precursors from a 3-deoxy-D-manno-octylosonic acid-deficient mutant of Salmonella typhimurium; Raetz CR et al.; Temperature-sensitive mutants of Salmonella typhimurium that are defective in the biosynthesis of 3-deoxy-D-manno-octulosonate are known to accumulate disaccharide precursor(s) of lipid A at 42 degrees C (Rick, P . D., Fung, L . W.-M., Ho, C., and Osborn, M . J . (1977) J . Biol . Chem . 252, 4904-4912) . We have devised new methods for purifying this material by chromatography on DEAE-cellulose and silicic acid columns and have fractionated it into eight related anionic components that fall into four sets, as judged by their charge . Substances IA and IB have an apparent net charge of -1, IIA and IIB of -2, IIIA and IIIB of -3, and IVA and IVB of -4 . Negative ion fast atom bombardment mass spectrometry reveals that the simplest component is IVA {( M - H}- at m/z 1404) . Compound IVA is also the most abundant, representing 30-50% of the accumulated lipids after 3 h at 42 degrees C . Structural studies of IVA, including NMR spectroscopy described in the accompanying paper, reveal that it consists of O-(2-amino-2-deoxy-beta-D-glucopyranosyl)-(1----6)-2-amino-2-deoxy-alpha - D-glucose, acylated at positions 2, 3, 2', and 3' with beta-hydroxymyristoyl moieties and bearing phosphate groups at positions 1 and 4' . Compound IIIA ({M - H}- at m/z 1527) contains an additional phosphoethanolamine residue, while IIA ({M - H}- m/z 1535) bears an aminodeoxypentose substituent, presumably 4-amino-4-deoxy-L-arabinose . Compound IA ({M - H}- at m/z 1658) bears both a phosphoethanolamine and an aminodeoxypentose . The compounds of the less abundant B series are further derivatized with an ester-linked palmitoyl moiety . Our results demonstrate that these precursors are far more heterogeneous than previously suspected. Experientia, 1985 Dec 15, 41(12), 1622 - 3 Antimutagenic unusual amino acids from plants; Minakata H et al.; Five unusual amino acids were identified as antimutagens against spontaneous mutation of Salmonella typhimurium TA100: L-azetidine-2-carboxylic acid (1) from Liliaceae plants, alpha-(methylenecyclopropyl)glycine (2) from Litchi chinensis seeds, and 2-amino-4-methylhex-5-ynoic acid (3), hypoglycin A (4), and (2S,4R)-2-amino-4-hydroxyhept-6-ynoic acid (5) from Euphoria longana seeds . The absolute stereochemistry of 5 was determined by its chiral synthesis from L-allylglycine, proving that 5 is the C-4 epimer of the amino acid previously isolated from dried longan seeds. J Biol Chem, 1985 Dec 15, 260(29), 15758 - 61 The covalent structure of the phase-1 flagellar filament protein of Salmonella typhimurium and its comparison with other flagellins; Joys TM; In order to circumvent problems associated with direct chemical analysis of the phase-1 flagellar filament protein (flagellin) of Salmonella typhimurium, the covalent structure was determined by recombinant DNA procedures . The corresponding structural gene (H-1i) was cloned into plasmid pBR322 in a 4.3-kilobase fragment produced by EcoRI digestion of chromosomal DNA, and the nucleotide sequence of the region specifying the flagellar protein was determined . Comparison of the data obtained with the limited information available for other salmonellar flagellins supported the concept that both ends of the molecule are conserved in this genus . Additionally, a conservation of base sequence in the region of H-1 genes coding for the N-terminal end of flagellins was apparent, suggesting that this area may have an additional regulatory role . The i flagellin was found to be unrelated to proteins in the NBRF data base with the exception of other flagellins . The three flagellins which have been sequenced to date (those produced by Bacillus subtilis, Caulobacter crescentis, and phase-1 S . typhimurium) show homologies in amino acid sequence at both the N-terminal and C-terminal ends despite large differences in their total molecular weight, and comparison suggests that B . subtilis and Salmonella are more closely related to each other than either is to Caulobacter. J Biol Chem, 1985 Dec 5, 260(28), 14965 - 70 Energy dependence of lipopolysaccharide translocation in Salmonella typhimurium; Marino PA et al.; Energy inhibitors block translocation of pulse-labeled core lipopolysaccharide to outer membrane under conditions which allow maintenance of constant specific radioactivity of intracellular precursor pools throughout the chase period . Under the conditions used, approximately 75% of the total cellular label was membrane-bound at initiation of chase . Translocation of core lipopolysaccharide from inner to outer membrane showed apparent first order kinetics (t1/2 = 1.2 min, 32 degrees C) . Translocation was blocked by arsenate (5-10 mM) under conditions where proton motive force was unchanged, while the uncouplers 2,4-dinitrophenol (0.1 mM to 0.8 mM) and carbonyl cyanide-m-chlorophenyl hydrazone (12-30 microM) inhibited translocation with no apparent effect on the ATP pool . Therefore, core lipopolysaccharide translocation appears to require maintenance of both proton motive force and high energy phosphate pools . Electron microscopic experiments show no gross disruption of zones of adhesion, the putative sites of lipopolysaccharide translocation, in the presence of arsenate or 2,4-dinitrophenol suggesting that energy is not required simply for maintenance of these structures. Biochemistry, 1985 Dec 3, 24(25), 7273 - 8 Mutagenesis by N4-aminocytidine: induction of AT to GC transition and its molecular mechanism; Negishi K et al.; N4-Aminocytidine is a potent mutagen toward Escherichia coli and Salmonella typhimurium . It induced reversion of an amber mutant of phi X174 phage (am3) to the wild type . This reversion was shown to be exclusively due to the AT to GC transition . It is likely that N4-aminocytidine is metabolized within the bacterial cells into N4-aminodeoxycytidine 5'-triphosphate and this nucleotide is incorporated into DNA during the multiplication of the cells and the phages, thereby causing base-pair transitions . The molecular basis for this erroneous replication was obtained in studies of in vitro incorporation of N4-aminodeoxycytidine 5'-triphosphate into polynucleotides catalyzed by the E . coli DNA polymerase I large fragment . The results have shown that this cytosine analogue can be efficiently incorporated as a substitute of cytosine and that it can also be incorporated as a substitute of thymine . The ratio in the rate of the N4-aminocytosine nucleotide incorporation to that of natural nucleotide incorporation was 1/2 to cytosine and 1/30 to thymine . Furthermore, the N4-aminocytosine residues in the polynucleotide templates can be read by the enzyme as efficiently as cytosines, and guanines were incorporated opposite to them. Z Lebensm Unters Forsch, 1985 Dec, 181(6), 455 - 7 {The mutagenicity of caramel colors}; Scheutwinkel-Reich M et al.; In the present study commercially available caustic and ammoniated caramel colours were tested for their mutagenic potential using the Ames assay . The test was performed using the standard test strains Salmonella typhimurium TA 1535, TA 1537, TA 98 and TA 100 with and without a metabolic activation system (S9-mix) . Furthermore, a special preincubation procedure without metabolic activation system was applied . None of the tested caramel colours showed any mutagenic effect in the Ames test. J Am Vet Med Assoc, 1985 Dec 1, 187(11), 1170 - 2 Cryptosporidiosis in young artiodactyls; Van Winkle TJ; Cryptosporidium was found in the intestinal tract of 10 blackbuck, 2 scimitar-horned oryx, 2 fringe-eared oryx, 2 addax, and 1 sable antelope that had diarrhea . Cryptosporidia were most numerous in the small intestine, but also were found in the cecum, spiral colon, and colon . The small intestine had minimal inflammation in association with the cryptosporidia . Salmonella typhimurium was isolated from 10 of the 51 animals evaluated, with extensive inflammation of the cecum, spiral colon, and colon observed in these animals. Food Chem Toxicol, 1985 Dec, 23(12), 1035 - 40 Effects of temperature, patty thickness and fat content on the production of mutagens in fried ground beef; Knize MG et al.; The high-pressure liquid chromatography (HPLC) profiles of mutagenic components were compared for extracts of ground beef patties fried at 200, 250 and 300 degrees C for 6 min/side . The HPLC profiles of the mutagenic samples were similar, although total mutagenic activity in Salmonella typhimurium TA1538 was roughly four times as high after the 300 degrees C than after the 200 degrees C frying . Six mutagenic peaks were analysed quantitatively at different temperatures and meat thicknesses . Two major components, 2-amino-3,8-dimethylimidazo{4,5-f}quinoxaline and 2-aminotrimethylimidazo{4,5-f}quinoxaline, and a minor component, 2-amino-3-methylimidazo{4,5-f}quinoline (IQ), were all present at the three different temperatures . Thus, in general, cooking temperature seems to have a major effect on the quantities of mutagens produced but not on their HPLC profiles . The thickness of the meat patty did not affect the total yield of mutagens except at longer cooking times (8-10 min/side) and, in general, neither did it affect the HPLC profiles of the mutagenic components . Total mutagenic activity increased with increasing cooking times . Increasing the fat content lowered the total mutagenicity, with 150,000 revertants/kg of fresh beef at 30% fat compared with 230,000 revertants/kg at 15%, but had little effect on the mutagenicity due to IQ. Mutat Res, 1985 Dec, 144(4), 221 - 5 Mutagenic activities of dictamnine and gamma-fagarine from dictamni radicis cortex (Rutaceae); Mizuta M et al.; A methanol extract of Dictamni Radicis Cortex exhibited a mutagenic effect on Salmonella typhimurium TA100 and TA98 with S9 mix . Two mutagenic compounds in Dictamni Radicis Cortex were isolated on a Sephadex LH 20 column and silica gel column chromatography and by preparative TLC . These were identified as dictamnine and gamma-fagarine by UV, EI-Mass, 1H-NMR . Dictamnine and gamma-fagarine were mutagenic in strain TA100 and TA98 with S9 mix . The dose-response curves were linear in the range 10-40 micrograms . Dictamnine and gamma-fagarine had specific activities (His+/microgram) of about 50-70 revertant colonies in strain TA100, while in strain TA98 there were about 30-50 revertant colonies. J Virol, 1985 Dec, 56(3), 1034 - 6 Map of DNA homology between the genomes of Salmonella bacteriophages P22 and L; Wiggins BA et al.; The genomes of temperate Salmonella typhimurium phages P22 and L share approximately 69% homology, as measured by DNA heteroduplex analysis . Alignment of the P22/L heteroduplex molecules with a P22 physical map places most of this homology between the capsid genes and genes in the vicinity of the prophage attachment sites . The degree of genetic relatedness between these phages and the lambdoid phages is also discussed. Cancer Res, 1985 Dec, 45(12 Pt 1), 6225 - 31 Rat and human explant metabolism, binding studies, and DNA adduct analysis of benzo(a)pyrene and its 6-nitro derivative; Garner RC et al.; Human colon and bronchus tissue explants were incubated with either {3H}benzo(a)pyrene ({3H}BP) or {3H}-6-nitrobenzo(a)pyrene ({3H}-6-NBP) . The total percentage of metabolism of BP and 6-NBP was, respectively, 8-59% and 18-41% in bronchus and 11-23% and 36-50% in colon . A product tentatively identified as 3-hydroxy-6-NBP was isolated from the 6-NBP incubation medium . BP and 6-NBP when incubated at equivalent concentrations were found to bind covalently to the DNA of human bronchi from 15 cases at means of 42 and 50.9 pmol/10 mg DNA, respectively, and to the DNA of human colon from 6 cases at means of 66.5 and 35 pmol/10 mg DNA, respectively . The range among individuals was within one order of magnitude . High pressure liquid chromatography (HPLC) of enzymic hydrolysates of human bronchus explant DNA revealed one adduct from the BP-incubated bronchus which cochromatographed with (+/-)-7,8-dihydroxy-9,10-epoxy-7,8,9, 10-tetrahydrobenzo(a)pyrene-deoxyguanosine and a possible two adducts from the 6-NBP-incubated bronchus which eluted earlier than did the BP adduct . DNA obtained from the lung or liver of rats given 2.0-mg/kg doses of either {3H}BP or {3H}-6-NBP by i.p . injection was also enzymically hydrolyzed and analyzed on HPLC . Three DNA adducts were observed in liver and two were observed in lung DNA hydrolysates from rats given injections of {3H}BP . One adduct from each organ cochromatographed with (+/-)-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene- deoxyguanosine; however, the major adduct in each case eluted earlier . Only one adduct was detected in liver and lung DNA hydrolysates from rats given {3H}-6-NBP, and this had the same retention time as did the major adduct isolated from human bronchus that had been incubated previously with {3H}-6-NBP . Salmonella typhimurium TA98 was incubated with {3H}-6-NBP and Aroclor-induced rat liver S9 . Enzymically hydrolyzed DNA analyzed by HPLC revealed three adducts, two of which cochromatographed with the two DNA adducts isolated from human bronchus DNA adduct which had the same retention time as did the major liver and lung DNA adduct from rats given i.p . injections of {3H}-6-NBP . In each case the major adduct from DNA hydrolysates of rat liver and lung, human bronchus, and S . typhimurium, all treated with {3H}-6-NBP, cochromatographed with the major DNA adduct isolated from liver and lung DNA of rats given {3H}BP.(ABSTRACT TRUNCATED AT 400 WORDS) Cancer Res, 1985 Dec, 45(12 Pt 1), 6155 - 9 Comparison of drug-metabolizing activities in the livers of carcinogen-sensitive parent rats and carcinogen-resistant descendants; Yoshimoto F et al.; Donryu strain albino rats were maintained on a diet containing 0.06% 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) for nine successive generations . Some rats in the fourth to eighth generations showed marked resistance to the carcinogenic action of 3'-Me-DAB . In the liver where we found tumors, their size and number are smaller than in the corresponding original strain of rats fed on a diet containing 3'-Me-DAB . No significant differences were found in the total cytochrome P-450 contents or epoxide hydrolase activities of the livers of the resistant variant and the original strain, but the benzo(a)pyrene hydroxylase activity which is mainly attributed to cytochrome P-448 and glutathione S-transferase activity of the resistant variant were lower . The inductions of hepatic cytochrome P-488 and benzo(a)pyrene hydroxylase on administration of polychlorinated biphenyls or 3-methylcholanthrene were also lower in the resistant rats . In the mutagenicity test on Salmonella typhimurium TA 98 the liver 9000 X g supernatant fraction from 3'-Me-DAB-resistant F7 rats did not fully induce the mutagenicities of 3'-Me-DAB and several other carcinogens . Thus the resistance of F7 rats to the chemical carcinogen may be related to the lower activities of some drug-metabolizing enzymes and the poor inducibility of cytochrome P-448 in their liver, although selection of resistant rats should be continued for further generations before coming to a definite conclusion on biochemical basis of apparent resistance to 3'-Me-DAB. Mutat Res, 1985 Dec, 147(6), 343 - 56 Structure-genotoxic activity relationships of pesticides: comparison of the results from several short-term assays; Klopman G et al.; The Computer-Automated Structure Evaluation (CASE) program has been applied to the analysis of the genotoxic activity of 54 pesticides (31 insecticides, 15 herbicides and 8 fungicides) in 5 different short-term test systems measuring gene mutation and DNA damage . The database contains compounds presenting diverse structures including carbamates, thiocarbamates, organophosphates, halo-aromatics and other functionalities . Some significant relationships between common structural features and the genotoxic activity displayed by these chemicals have been found . Among the most relevant fragments, automatically selected by the program, a methoxyphosphinyl and a chlorovinyl group appear as the common structural subunits responsible for the activities detected in the battery composed of the Salmonella typhimurium histidine reversion assay, the mouse lymphoma gene mutation assay and recombination in the yeast Saccharomyces cerevisiae. Acta Pathol Microbiol Immunol Scand {B}, 1985 Dec, 93(6), 411 - 5 Spectrofluorometric and microfluorometric quantitation of antibacterial antibodies, using indirect immune fluorescence . Preliminary report; Magnusson KE; The IgG-fraction of rabbit hyperimune serum raised towards smooth Salmonella typhimurium 395 MS (parent strain) and rough 395 MR10 (Rd-mutant) was used in indirect immunofluorescence with bacteria in suspension or adsorbed to glass microscope slides . In the first case, IgG-mediated fluorescence was determined with a standard cuvette-type spectrofluorometer; in the second case, in epifluorescence mode with a microscope fluorometer . In both assays the IgG solution could be diluted to about 0.1 micrograms per ml protein to allow detection of fluorescent anti-IgG antibodies in the second step . When determined by the spectrofluorometric method, the IgG antibody titres against S . enteritidis in two patients sera were 1/320 and 1/1280, respectively, which was compared to antibody titres determined with ELISA and MrPAH . Either mode of fluorescence measurement appears to give an objective but arbitrary value of the indirect immuno-fluorescence from bacteria and allows detection of antibodies directed towards whole bacteria, i.e . all antigenic determinants exposed . This may be of importance when following infectious processes . Furthermore, no extraction and binding of bacterial envelope components to solid supports is necessary. Zentralbl Bakteriol Mikrobiol Hyg {A}, 1985 Dec, 260(4), 448 - 58 Proteins from Salmonella R-mutants mediating protection against Salmonella typhimurium infection in mice . III . Separation and purification of soluble proteins and their use as vaccines and as precipitating antigens; Bhatnagar N et al.; Urea extracts of Salmonella-S-form and R-mutant bacteria were separated into water-soluble and water-insoluble fractions and analysed with respect to their chemical composition . The main portion of proteins which at the same time represented the majority of the different polypeptides, was found in the water soluble fraction . This fraction, in the case of R-mutants, exhibited a considerably lower contamination with LPS and phospholipid than the total urea extract . This facilitated the further purification of proteins which could thus be carried out in urea-free buffer systems . In mice infected with S . typhimurium, the water soluble fraction afforded protection to the same extent as the total urea extract . The purified soluble proteins of Salmonella-R-mutants exhibited protective activity to injection with S . typhimurium and S . heidelberg comparable to that seen with the soluble extract . A species overlapping character of the protection became evident . In the Ouchterlony gel precipitation test, using the water soluble fraction and purified proteins as antigens, antibodies could be detected in rabbit immune sera and in sera of patients with Salmonella infections. Sci Total Environ, 1985 Dec, 47, 257 - 64 Mutagenic activity in humic water and alum flocculated humic water treated with alternative disinfectants; Backlund P et al.; Mutagenic activity in Salmonella typhimurium strains TA 100, TA 98 and TA 97 has been determined for humic water and alum flocculated humic water, treated with the alternative disinfectants chlorine, ozone, chlorine dioxide, ozone/chlorine and chlorine/chlorine dioxide . The most pronounced activity was found for chlorine treated water tested on strain TA 100 without metabolic activation (S9 mix) . Ozone treatment prior to chlorination did not alter the activity, while treatment with chlorine in combination with chlorine dioxide reduced the activity to a level somewhat over the background . No mutagenic response was detected in waters treated with ozone or chlorine dioxide alone . In presence of S9 mix all water extracts studied were non-mutagenic. Mutat Res, 1985 Dec, 158(3), 141 - 7 Mutagenicity of some dialkylnitrosamines, cyclic nitrosamines and N,N-diethanolnitrosamine in Salmonella typhimurium with rat and rabbit nasal, lung and liver S9 homogenates; Dahl AR; 6 nitrosamines, 5 of which cause rat nasal cancer, were tested for mutagenicity in the TA100 strain of S . typhimurium with rat and rabbit nasal, lung and liver S9 homogenates . The TA98 strain also was used with rabbit tissue homogenates . The two cyclic nitrosamines tested, N-nitrosopiperidine and N-nitrosopyrrolidine, were substantially mutagenic with all rabbit tissue homogenates in TA100, but in the rat only nasal homogenate was effective in activating them . N-Nitrosodi(n)propylamine also was activated by rat nasal tissue homogenate but not by the other rat or rabbit tissue homogenates . Diethanolnitrosamine was a direct mutagen in both TA100 and TA98 . N-Nitrosodimethylamine and N-nitrosodiethylamine were not mutagenic under any test conditions . The results indicate that some nitrosamines that cause nasal cancer can be activated by nasal enzymes and that possibly important differences in activating capabilities occur among respiratory tract and hepatic tissues and among animal species. Mutat Res, 1985 Dec, 158(3), 129 - 33 Mutagenicity of acrylamide and its analogues in Salmonella typhimurium; Hashimoto K et al.; Acrylamide and its 15 analogues have been tested for mutagenicity in 5 TA strains of Salmonella typhimurium . Acrylamide, N-tert-butylacrylamide, crotonamide, diacetone acrylamide, N,N-diethylacrylamide, N,N-dimethylacrylamide, N-hydroxymethylacrylamide, N-methylacrylamide, N-isobutoxymethylacrylamide, N-isopropylacrylamide, methacrylamide, N,N'-methylene-bis-acrylamide and N-tert-octylacrylamide appeared not to be mutagenic in the standard Ames assay both with and without Aroclor 1254-induced S9, and in both the plate incubation and liquid preincubation procedures . Three epoxide analogues, i.e., glycidamide, N,N-diglycidyl acrylamide and glycidyl methacrylamide showed mutagenicity in one or two strains both with and without the S9. Mutat Res, 1985 Dec, 158(3), 119 - 24 Appearance of direct-acting mutagenicity of various foodstuffs produced in Japan and Southeast Asia on nitrite treatment; Wakabayashi K et al.; After nitrite treatment, various kinds of pickled vegetables and sun-dried fishes produced in Japan showed direct-acting mutagenicity on Salmonella typhimurium TA100, inducing 1900-18000 revertants/g . Kimchis, sun-dried fishes, sun-dried squid, soy sauces, fish sauces, bean pastes and shrimp paste produced in Korea, the Philippines and Thailand also showed direct-acting mutagenicity after nitrite treatment . All soy sauces and fish sauces tested contained as much tyramine as 17-1020 micrograms/ml, but very low or undetectable amounts of (-)-(1S,3S)- and (-)-(1R,3S)-1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acids. Food Chem Toxicol, 1985 Dec, 23(12), 1041 - 7 Mutagenicity tests of lipid oxidation products in Salmonella typhimurium: monohydroperoxides and secondary oxidation products of methyl linoleate and methyl linolenate; MacGregor JT et al.; Nine hydroperoxy and hydroperoxy-epidioxy oxidation products derived from either autoxidation (AO) or photosensitized oxidation (PO) of methyl linoleate (MLo) or methyl linolenate (MLn) were tested for mutagenic activity by the Salmonella typhimurium his+ reversion assay using strains TA100, TA98, TA102, TA97 and TA1537 . All nine oxidation products, monohydroperoxides from AO-MLn (I) or from PO-MLn (II), dihydroperoxides from PO-MLo (III), AO-MLn (IV) or PO-MLn (V), hydroperoxy epidioxides from PO-MLo (VI), AO-MLn (VII) or PO-MLn (VIII) and hydroperoxy bis-epidioxides from PO-MLn (IX), were weakly mutagenic in strains TA97 and/or TA100 . The hydroperoxy epidioxides (VI-IX) exhibited significantly greater activity in strain TA97 than did the monohydroperoxides (I, II) or the dihydroperoxides (III-V) . In strain TA100, all of the oxidation products tested exhibited similar activity . No major differences between products derived from autoxidized and photooxidized MLn (I v . II, IV v . V, VII v . VIII) were obtained . Rat-liver S-9 reduced the toxicity of all oxidation products to the tester strains . The greatest mutant yields were usually obtained in the presence of S-9, but mutagenic potency was sometimes greater without S-9 . The structural feature common to all of the mutagenic oxidation products was the presence of a hydroperoxy group, suggesting that this characteristic is responsible for the observed mutagenicity, either directly or through a common degradative pathway to reactive products of lower molecular weight. Mutat Res, 1985 Dec, 144(4), 231 - 7 Carcinogenic N-hydroxylaminopurine derivatives do not act as base analog mutagens in Salmonella typhimurium; McCartney M et al.; N-Hydroxylaminopurines are highly mutagenic for growing as well as resting Salmonella typhimurium strain TA100 and to a lesser extent for strain TA98 . Aminopurines, under similar conditions, are not mutagenic . N-Methylhydroxylaminopurine, under similar conditions, exhibits only minimal activity . The results are taken to indicate that unlike non-hydroxylated aminopurines, N-hydroxylaminopurines exert their mutagenicity not by acting as base analogs but by direct covalent binding with DNA-guanine. Mutat Res, 1985 Dec, 144(4), 227 - 30 Implication of hydrogen peroxide in the mutagenicity of coffee; Fujita Y et al.; A cup of instant coffee (150 ml) of normal strength (15 mg/ml) was found to contain about 500 and 750 micrograms of hydrogen peroxide soon after its preparation at 37 degrees C and 80 degrees C, respectively, but the concentration of hydrogen peroxide in the coffee increased with time for up to 24 h after its preparation . Thus coffee contains a hydrogen peroxide generating system . As extracts of green coffee beans were found to have very low capacity to generate hydrogen peroxide, this generating system is produced by roasting coffee beans . Hydrogen peroxide itself was only weakly mutagenic to Salmonella typhimurium TA100, but in the presence of methylglyoxal, which is also present as a mutagenic component in coffee, hydrogen peroxide showed strong mutagenicity . Hydrogen peroxide and methylglyoxal seem to be responsible for most of the mutagenicity of instant coffee. J Bacteriol, 1985 Dec, 164(3), 1370 - 2 Excretion of unassembled hook-associated proteins by Salmonella typhimurium; Homma M et al.; Hook-associated proteins (HAPs) were excreted into the culture medium of the Fla+ strain as well as into the growth medium of the filamentless mutants of Salmonella typhimurium . This indicates that the bacteria synthesize HAPs excessively, beyond the amount required for construction of flagella . The extra HAPs are shed into the culture medium after a definite amount of each HAP has been assembled into the flagellar structure. J Bacteriol, 1985 Dec, 164(3), 1224 - 32 Osmoregulation of gene expression in Salmonella typhimurium: proU encodes an osmotically induced betaine transport system; Cairney J et al.; Previous evidence has indicated that a gene, proU, is involved in the response of bacterial cells to growth at high osmolarity . Using Mu-mediated lacZ operon fusions we found that transcription of the proU gene of Salmonella typhimurium is stimulated over 100-fold in response to increases in external osmolarity . Our evidence suggests that changes in turgor pressure are responsible for these alterations in gene expression . Expression of proU is independent of the ompR gene, known to be involved in osmoregulation of porin expression . Thus, there must be at least two distinct mechanisms by which external osmolarity can influence gene expression . We show that there are relatively few genes in the cell which are under such osmotic control . The proU gene is shown to encode a high-affinity transport system (Km = 1.3 microM) for the osmoprotectant betaine, which is accumulated to high concentrations in response to osmotic stress . Even when fully induced, this transport system is only able to function in medium of high osmolarity . Thus, betaine transport is regulated by osmotic pressure at two levels: the induction of expression and by modulation of activity of the transport proteins . We have previously shown that the proP gene encodes a lower-affinity betaine transport system (J . Cairney, I . R . Booth, and C . F . Higgins, J . Bacteriol., 164:1218-1223, 1985) . In proP proU strains, no saturable betaine uptake could be detected although there was a low-level nonsaturable component at high substrate concentrations . Thus, S . typhimurium has two genetically distinct pathways for betaine uptake, a constitutive low-affinity system (proP) and an osmotically induced high-affinity system (proU). J Bacteriol, 1985 Dec, 164(3), 1218 - 23 Salmonella typhimurium proP gene encodes a transport system for the osmoprotectant betaine; Cairney J et al.; Betaine (N,N,N-trimethylglycine) can be accumulated to high intracellular concentrations and serves an important osmoprotective function in enteric bacteria . We found that the proP gene of Salmonella typhimurium, originally identified as encoding a minor transport system for proline (permease PP-II), plays an important role in betaine uptake . Mutations in proP reduced the ability of betaine to serve as an osmoprotectant . Transport of betaine into the cells was also severely impaired in these mutants . The kinetics of uptake via PP-II suggest that betaine, rather than proline, is the important physiological substrate for this transport system . Betaine uptake via PP-II was regulated by osmotic pressure at two different levels: transcription of the proP gene was increased by increasing osmolarity, and, in addition, activity of the transport system itself was dependent upon the osmotic pressure of the medium . The specificity of the transport system was also altered by increasing osmolarity which enhanced the affinity for betaine while reducing that for proline. Infect Immun, 1985 Dec, 50(3), 716 - 20 Detection of antibodies against lipopolysaccharides of Escherichia coli and Salmonella R and S strains by immunoblotting; de Jongh-Leuvenink J et al.; Antisera raised against several smooth and rough strains of Escherichia coli and Salmonella typhimurium were tested against lipopolysaccharides (LPS) of homologous and heterologous strains . The LPS were separated by sodium dodecyl sulfate-gel electrophoresis, transferred to nitrocellulose paper, and overlaid with antisera . The results showed that antisera raised against smooth strains reacted with high- as well as low-molecular-weight bands of their corresponding LPS and showed very few cross-reactions . Anti-E . coli J5 antiserum cross-reacted with few strains in the core region . But, anti-S . typhimurium Ra antiserum cross-reacted with many more strains . When these sera were absorbed with either the homologous- or a heterologous-positive strain, reactions were abolished . It appears that reactions of anti-E . coli J5 antiserum and anti-S . typhimurium Ra antiserum with homologous and heterologous strains were not due to the same antibody . This immunoblotting technique proved to be a useful method to distinguish different antibodies in antiserum raised against LPS of gram-negative bacteria. Infect Immun, 1985 Dec, 50(3), 695 - 700 Characterization of monoclonal antibodies against Shiga-like toxin from Escherichia coli; Strockbine NA et al.; Three monoclonal antibodies, designated MAb 16E6, MAb 13C4, and MAb 19G8, were produced which recognize Shiga-like toxin (SLT) from Escherichia coli . All three monoclonal antibodies neutralized the cytotoxicity of E . coli SLT and were able to immunoprecipitate intact labeled toxin with Staphylococcus aureus protein A . The three antibodies were of the G1 heavy and kappa light chain classes . MAb 16E6 bound to the B subunit of SLT in Western blots and also neutralized the lethality of the toxin for mice and the enterotoxicity of the toxin in ligate rabbit ileal loops . The ability of MAb 16E6 to neutralize the cytotoxicity, lethality, and enterotoxicity of E . coli confirms the hypothesis that all three activities are associated with a single toxin . MAb 16E6 and MAb 13C4 also neutralized the cytotoxicity of purified Shiga toxin from Shigella dysenteriae type 1 and Shiga-like toxic activities in crude cell extracts from Shigella flexneri, Vibrio cholerae, Vibrio parahaemolyticus, and Salmonella typhimurium . Thus, Shiga toxin and the SLTs from E . coli, Shigella flexneri, V . cholerae, V . parahaemolyticus, and Salmonella typhimurium share a common B subunit epitope that is involved in neutralization . MAb 13C4 has been successfully used in a colony blot assay for the detection of bacterial colonies which produce high levels of SLT . Sixty-two different strains of bacteria were tested by both the cytotoxicity and colony blot assays for the presence of SLT . The colony blot assay detected all strains of bacteria which produce greater than or equal to 10(5) 50% cytotoxic doses of SLT per ml of sonic lysate . There were no false-positive results among the 62 samples tested. Carcinogenesis, 1985 Dec, 6(12), 1811 - 3 Chemical impurity as the possible cause of nitrofen mutagenicity; Seiler JP; The results of Salmonella mutagenicity tests with the herbicide nitrofen (2,4-dichlorophenyl-4-nitrophenyl ether, CAS 1836-75-5) reported in the literature seem to vary according to source or lot of the technical product . This behaviour could be reproduced in our experiments, and it could be traced to the varying content of bis(4-nitrophenyl) ether in nitrofen . Nitrofen samples with the highest bis(4-nitrophenyl) ether concentrations proved to exhibit also the highest mutagenic activities, while the one containing no bis(4-nitrophenyl) ether was also devoid of mutagenic activity towards Salmonella typhimurium TA 100. J Appl Bacteriol, 1985 Dec, 59(6), 507 - 12 Reference material for the evaluation of a standard method for the detection of salmonellas in foods and feeding stuffs; Beckers HJ et al.; To evaluate a standard salmonella isolation method a reference material consisting of 0.2 g spray-dried milk inoculated with Salmonella typhimurium and contained in gelatin capsules was prepared . The organisms were distributed homogeneously between capsules, and their numbers were stable for 120 d when the capsules were stored in dry conditions at 4 degrees C . Addition of these capsules with or without food samples to pre-enrichment broth gave low and reproducible levels of Salm . typhimurium contamination without altering the pre-enrichment and without influencing the other bacterial flora present . As a result of an interlaboratory trial, the reference material indicated that the food and/or its competitive flora may have a negative influence on the detection of salmonellas. Virology, 1985 Dec, 147(2), 431 - 40 Bacteriophage L: chromosome physical map and structural proteins; Hayden M et al.; Restriction endonuclease cleavage site mapping was used to locate the regions of highest sequence homology in the chromosomes of Salmonella typhimurium bacteriophages L and P22 . These lie in the DNA packaging, tail, early transcription antitermination, and perhaps integration "gene modules." Other regions of the two genomes are substantially less closely related . Phage L, which has no functional immunity I region, lacks approximately 1300 bp of DNA when compared to P22 in this section of the chromosome . At least some of the virion structural proteins are interchangeable between the two phages, which suggests that the two phage structural protein genes are very closely related . In addition, the apparent molecular weights of most P22 and L phage structural proteins are very similar . However, the phage L virion contains about 140 molecules of a 15K capsid protein which apparently has no P22 analog. Proc Natl Acad Sci U S A, 1985 Dec, 82(23), 7989 - 93 Homologies between the Salmonella typhimurium CheY protein and proteins involved in the regulation of chemotaxis, membrane protein synthesis, and sporulation; Stock A et al.; Chemotactic receptors at the bacterial cell surface communicate with flagellar basal structures to elicit appropriate motor behavior in response to extracellular stimuli . Genetic and physiological studies indicate that the product of the cheY gene interacts directly with components of the flagellar motor to control swimming behavior . We have purified and characterized the Salmonella typhimurium CheY protein and have determined the nucleotide sequence of the cheY gene . Amino acid sequence comparisons showed CheY to be homologous over its entire length (129 residues) to the N-terminal regulatory domain of another protein involved in chemotaxis, the CheB methyl esterase . The entire CheY protein and the regulatory domain of CheB also homologous to the N-terminal portions of the Escherichia coli OmpR and Dye proteins and the Bacillus subtilis Spo0A protein . These homologies suggest an evolutionary and functional relationship between the chemotaxis system and systems that are thought to regulate gene expression in response to changing environmental conditions. J Med Microbiol, 1985 Dec, 20(3), 345 - 53 Haemagglutinins and adhesion of Escherichia coli to HEp2 epithelial cells; Tavendale A et al.; Strains of Escherichia coli producing type-1 fimbriae, associated with mannose-sensitive haemagglutinin (MSHA), or three antigenically different kinds of 'MRE' fimbriae, associated with mannose-resistant and eluting haemagglutinins (MREHAs), adhered poorly to HEp2 epithelial cells in an in-vitro adhesion model previously used to demonstrate the importance of motility and type-1 fimbriae for the attachment of strains of Salmonella typhimurium to HEp2 cells . Strains of E . coli producing narrow-spectrum MREHA, agglutinating human erythrocytes only of 14 red-cell species tested, adhered well to HEp2 cells, particularly so when bacteria produced MSHA (and type-1 fimbriae) along with the narrow-spectrum 'man-only' MREHA . These findings are discussed with regard to recent observations suggesting that narrow-spectrum 'man-only' MREHA in E . coli may be associated with fine, fibrillar appendages 2-nm wide. Biochem Biophys Res Commun, 1985 Nov 15, 132(3), 1144 - 50 Specific recognition of altered polypeptides by widely distributed methyltransferases; O'Connor CM et al.; Protein carboxyl methyltransferase activity has been detected in extracts prepared from bacterial cells (Salmonella typhimurium), amphibian (Xenopus laevis) oocytes, and transformed mammalian cell lines . This activity appears to specifically recognize altered aspartyl residues based on the observation that the synthetic peptide L-Val-L-Tyr-L-Pro-L-isoAsp-Gly-L-Ala is a good methyl-accepting substrate for the methyltransferase activity, but that the corresponding peptide containing a normal L-aspartyl residue is not . These activities are similar to those of the previously described human erythrocyte and bovine brain enzymes which catalyze the formation of polypeptide D-aspartyl beta-methyl esters and L-isoaspartyl alpha-methyl esters . The wide distribution of these enzymatic activites suggest that the methylation of atypical proteins is an essential function in cells. Nucleic Acids Res, 1985 Nov 11, 13(21), 7591 - 606 The nucleotide sequence of the nitrogen regulation gene ntrB and the glnA-ntrBC intergenic region of Klebsiella pneumoniae; MacFarlane SA et al.; The nucleotide sequence of the Klebsiella pneumoniae ntrB gene and the glnA-ntrBC intergenic region has been determined . NtrB encodes a 38,409 Dalton polypeptide with a potential DNA-binding domain between residues 67 and 86 . This N-terminal domain may play a role in the co-operative control of ntr-regulated promoters by the ntrB and ntrC products . Mapping of in vivo transcripts with S1 nuclease identified three transcripts in the glnA-ntrBC intergenic region . Two transcripts originate upstream of glnA; one reading through into ntrBC and one terminating at a sequence resembling a rho-independent terminator between glnA and ntrBC . A third transcript originates from the ntrBC promoter which has a consensus binding site for the ntrC product in the -10 region . Comparison of the glnA-ntrBC intergenic sequences from K . pneumoniae, Escherichia coli and Salmonella typhimurium has identified a number of conserved features and some significant differences. Cancer Res, 1985 Nov, 45(11 Pt 1), 5421 - 5 Identification of mutagenic metabolites of indeno{1,2,3-cd}pyrene formed in vitro with rat liver enzymes; Rice JE et al.; Indeno{1,2,3-cd}pyrene (IP) is a major environmental pollutant which is carcinogenic on mouse skin and in rat lung . Unlike benzo(a)pyrene, IP is a nonalternant polycyclic aromatic hydrocarbon which is devoid of a bay region . IP was mutagenic in Salmonella typhimurium TA100 in the presence of a 9000 X g supernatant from the livers of Aroclor-pretreated rats . Using a similar activation system, the major metabolites of IP were isolated and identified by comparison with synthetic reference standards . trans-1,2-Dihydro-1,2-dihydroxy-IP, 8-, 9-, and 10-hydroxy-IP, 8- and 9-hydroxy-trans-1,2-dihydro-1,2-dihydroxy-IP, and IP-1,2-quinone are among the metabolites formed in vitro . The 1,2-epoxide of indeno{1,2,3-cd}pyrene is a potent direct-acting mutagen . 8- and 9-hydroxy-IP were mutagenic with metabolic activation . 1-,2-, and 6-hydroxy-IP and the trans-1,2-dihydrodiol had no significant mutagenic activity in S . typhimurium TA100 with metabolic activation . These data suggest that the K-region oxides of IP and of 8- and 9-hydroxy-IP are ultimately responsible for its mutagenic activity. Mutat Res, 1985 Nov-Dec, 152(2-3), 125 - 9 3-Methoxy-4-aminoazobenzene, a unique carcinogenic aromatic amine as a substrate for cytochrome-P-450-mediated mutagenesis; Degawa M et al.; Rat liver microsomal enzyme(s) that catalyze mutagenic activation of a carcinogenic aminoazo dye, 3-methoxy-4-aminoazobenzene (3-MeO-AAB), was studied by virtue of the Salmonella typhimurium TA98 assay using o-aminoazotoluene (OAT) as the control . Male Wistar rats were pretreated with phenobarbital (PB), 3-methylcholanthrene (MC) or polychlorinated biphenyl (PCB), and the liver microsomal activities for mutagenic activation of 3-MeO-AAB and OAT were examined . In agreement with the reported results on several carcinogenic aromatic amines, MC pretreatment resulted in greater activation of microsomal activity in the OAT mutagenesis (about a 4-fold increase as compared to the untreated control) than did PB (1.5-fold increase) . By contrast, the mutagenic activation of 3-MeO-AAB is found to be more efficiently catalyzed by those enzyme(s) that are induced by PB pretreatment (4-fold increase) than by those that are induced by MC (1.8-fold increase) . The induced enzymes that principally mediate the mutagenic activation of these azo dyes are indicated to be cytochrome P-450s, because the mutagenic activation was strongly inhibited by addition of cytochrome P-450 inhibitors such as 2-diethylaminoethyl-2,2-diphenylvalerate (SKF 525A) and 7,8-benzoflavone . These data suggest that 3-MeO-AAB is a unique carcinogenic aromatic amine as a substrate for mutagenic activation via catalysis of those cytochrome P-450s that are induced by PB pretreatment. Mutat Res, 1985 Nov, 144(3), 119 - 25 Activation of sodium cyanide to a toxic but non-mutagenic metabolite in Salmonella typhimurium; Owais WM et al.; Salmonella typhimurium strains (OASS-positive) synthesize a toxic but non-mutagenic metabolite from cyanide and O-acetylserine . Salmonella typhimurium mutant DW379 (OASS-deficient) is neither able to carry out this reaction in vitro nor produce the toxic metabolite in vivo . L-Cysteine reverses the cyanide metabolite mediated inhibition and thus allows OASS-positive strains to grow in medium containing cyanide and O-acetylserine . The results suggest that the enzyme O-acetylserine sulfhydrylase catalyzes the reaction of cyanide and O-acetylserine to form the toxic metabolite . This metabolite is ninhydrin-positive, adheres strongly to the cation-exchange column, and migrates in TLC to an Rf value similar to that of beta-cyanoalanine. J Leukoc Biol, 1985 Nov, 38(5), 635 - 47 Continuous expression of I-A antigen by peritoneal macrophages from mice resistant to Mycobacterium bovis (strain BCG); Johnson SC et al.; Monoclonal antibodies were used to monitor the expression of I-A antigen on the surface of macrophages obtained from mice immunized to Mycobacterium bovis (strain BCG) . Unlike the transient nature of I-A expression by macrophages from Listeria-injected mice, peritoneal macrophages from mice injected 28 days previously with 10(4) BCG expressed I-A continuously . The continued expression was not due to the presence of antigen or of contaminating lymphocytes . When we compared the kinetics of I-A expression from different strains of mice, the continuous expression of I-A correlated with the genetic resistance of the mice to BCG . Macrophages from mice that were resistant to BCG expressed I-A continuously, while macrophages from BCG susceptible mice expressed I-A transiently . Injection of resistant mice with Salmonella typhimurium did not result in the induction of a population of macrophages that expressed I-A continuously . This suggests that the Bcg gene may not be the same as that responsible for resistance to Salmonella (Ity) or Leishmania (Lsh). Sangyo Igaku, 1985 Nov, 27(6), 400 - 19 The results of microbial mutation test for forty-three industrial chemicals; Shimizu H et al.; The mutagenicity of 43 industrial chemicals in Salmonella typhimurium (TA98, TA100, TA1535, TA1537, and TA1538) and Escherichia coli (WP2uvrA) was examined . The output of these chemicals in Japan is more than a million kilograms per year . The mutation test was carried out under the condition of absence and presence of rat microsomal activation . Two chemicals, hexamethylenetetramine and 4,4'-methylenediphenyldiisocyanate, showed mutagenic activity in S . typhimurium TA98 and TA100 by metabolic activation . Hexamethylenetetramine also showed mutagenic activity in TA98 without microsomal activation . No mutagenic activity was observed in the 41 chemicals including 4 volatile and gaseous compounds. Appl Environ Microbiol, 1985 Nov, 50(5), 1279 - 84 Molecular analysis confirms food source and simultaneous involvement of two distinct but related subgroups of Salmonella typhimurium bacteriophage type 10 in major interprovincial Salmonella outbreak; Bezanson GS et al.; More than 2,000 confirmed cases of food poisoning occurred in the four Atlantic provinces of Canada and in Ontario during the second and third quarters of 1984 . Salmonella typhimurium phage type 10 was identified as the etiologic agent, and cheddar cheese was implicated as the source of infection . Strains isolated from infected humans and from cheese were indistinguishable by biotyping, antibiotic resistance typing, and phage typing . Plasmid analysis confirmed cheese as the source of infection and revealed the presence of two molecular subgroups of bacteriophage type 10 . Group I strains carried 57-, 22.3-, and 3.4-kilobase (kb) plasmids; group II strains carried 57-, 4.6-, and 3.4-kb plasmids . Digestion with endonucleases HaeIII, HpaII, and AvaIII indicated that the 3.4-kb plasmids were identical . This outbreak was, therefore, caused by a mixed infection with two distinct but related bacteria . Group I strains are fairly common among Canadian S . typhimurium phage type 10 isolates, whereas group II strains appeared to be unique to this outbreak. Sci Total Environ, 1985 Nov, 46, 229 - 41 Mutagenicity of chlorinated products from soil humic substances; Sato T et al.; Soil humic substances were chlorinated in solution, extracted with ether and subjected to mutagenicity assay . Mutagenicity was detected using Salmonella typhimurium TA 100, with or without S9 mix; mutagenic activity was found to be less with added S9 mix . Ether extracts were analyzed by gas chromatography-mass spectrometry (GC-MS) and various chlorinated and non-chlorinated compounds were detected, e.g . chlorinated esters, acetones and carboxylic acids, as well as non-chlorinated aromatics . The mutagenicity of the major chlorination products was examined . Chloral and 1,1,1,3,3-pentachloro-2-propanone (pentachloroacetone) were found to be mutagenic, and 1,1-dichloro-2-propanone (1,1-dichloroacetone) was a possible mutagen . The yields of these mutagens increased with an increase in chlorine concentration. Arch Microbiol, 1985 Nov, 143(2), 105 - 10 Fungal metabolism and detoxification of polycyclic aromatic hydrocarbons; Cerniglia CE et al.; The mutagenic activity of ethyl acetate extracts of culture medium from Cunninghamella elegans incubated 72 h with various polycyclic aromatic hydrocarbons (PAHs) was evaluated in the Salmonella typhimurium reversion assay . All of the PAH extracts were assayed in tester strains TA98 and TA100 both with and without metabolic activation using a liver fraction from Aroclor 1254-treated rats . None of the extracts from fungal incubations with the mutagenic PAHs, benzo{a}pyrene, 7,12-dimethylbenz{a}anthracene, 3-methylcholanthrene and benz{a}anthracene, as well as the non-mutagenic PAHs, naphthalene, phenanthrene and anthracene, displayed any appreciable mutagenic activity . In addition, time course experiments indicated that the rate of decrease in mutagenic activity in the extracts from cultures incubated with benzo{a}pyrene or 7,12-dimethylbenz{a}anthracene was coincident with the rate of increase in total metabolism . The results demonstrated the ability of the fungus C . elegans to detoxify known carcinogens and mutagens and suggests that this organism may play an important role in the metabolism and inactivation of PAHs in the environment. Mutat Res, 1985 Nov-Dec, 152(2-3), 131 - 45 Carcinogens induce genetic tandem duplications in Salmonella; Pall ML et al.; Extensive studies have shown that chemical carcinogenesis involves an initiation-promotion pattern . A gene amplification model of carcinogenesis predicts that initiation involves induction of a genetic tandem duplication . We use a system developed by Anderson and Roth to select for tandem duplication of the histidine operon of Salmonella typhimurium by selection for resistance to 3-amino-1,2,4-triazole . Evidence reported here shows that, consistent with prediction, 10 carcinogens are all active in inducing tandem duplications . Two toxic noncarcinogens show little or no activity under the conditions used in inducing tandem duplication but azide, a mutagenic noncarcinogen, did show some activity . 9 types of evidence now support the gene amplification initiation-promotion model of carcinogenesis. Mutat Res, 1985 Nov, 144(3), 131 - 6 The synthesis and mutagenicity of the 3-ethyl analogues of the potent mutagens IQ, MeIQ, MeIQx and its 3,7-dimethyl isomer; Jagerstad M et al.; The title compounds were synthesized and tested for mutagenicity on Salmonella typhimurium TA98 in the presence of S9 mix . All test compounds showed lower activity than their respective 3-methyl analogues (IQ compounds) . The replacement of the 3-methyl by an ethyl group should not alter the chemistry of these compounds; hence, their lower mutagenic activity could merely be of steric origin. J Nutr, 1985 Nov, 115(11), 1403 - 8 Differential effect of dietary protein type on the B-cell and T-cell immune responses in mice; Bounous G et al.; The effect of 20 g/100 g diet of lactalbumin (L), casein (C), soy (S) and wheat (W) protein on the immune responsiveness of C3H/HeN mice has been investigated by measuring the humoral immune response to the T cell-independent antigen, TNP-Ficoll . The humoral immune response of mice fed the L diet was found to be higher than that of mice fed the C, S and W diets . On the other hand, delayed-type hypersensitivity, and splenic cell mitogen responses to phytohemagglutinin and concanavalin A did not differ among mice fed the various diets . Similarly, the type of diet did not appear to influence host resistance to Salmonella typhimurium . It is postulated that the type of protein in the diet influences directly the intrinsic capacity of the B lymphocytes to respond to an immunogenic stimulus. J Immunol, 1985 Nov, 135(5), 3473 - 8 Relationship between immune system and gram-negative bacteria . IV . T lymphocytes from Lpsd mice possess binding site(s) for Rb Salmonella; Jirillo E et al.; We have previously shown that Salmonella minnesota R345 (Rb) spontaneously binds to 50 to 55% of human peripheral blood mononuclear cells (PBMC) . In the present study, we have compared Rb cytoadherence to lymphoid cells from various tissues of lipopolysaccharide (LPS) hyporesponsive (Lpsd) and LPS responsive (Lpsn) mouse strains . A higher number of spleen cells from Lpsd mice (C3H/HeJ and C57BL/10ScN) bound Rb bacteria (22 to 30%) than cells from Lpsn mice (4 to 9%) . Rb bound mainly to T cells, and cytoadherence occurred in both Lyt-1+ and Lyt-2+ T cell subsets . By contrast, purified splenic B cells from Lpsd and Lpsn mice gave less than 4% Rb cytoadherence . In both mouse strains, cytoadherence was mediated by the homologous LPS structure, because purified Rb-LPS blocked Rb Salmonella binding to T cells . On the other hand, smooth Salmonella typhimurium LT-2 LPS (S-LPS) and Salmonella R595 (Re) LPS (Re-LPS), which contain mainly lipid A, were without effect on Rb binding . Increased Rb binding was seen with T cells from Peyer's patches (PP), mesenteric lymph nodes (MLN), and peripheral blood than from spleen of C3H/HeN (Lpsn) mice; however, greater cytoadherence was always seen with T cells of these tissues from C3H/HeJ mice . Interestingly, treatment of whole spleen or purified T cells from C3H/HeN mice with neuraminidase enhanced cytoadherence to levels seen with C3H/HeJ cells . The observed Rb binding to PP, MLN, and PBMC cells in both mouse strains suggests that gut microbial environment may play an important role in Rb cytoadherence . This is also supported by the evidence that when spleen cells of germfree and conventional mice were tested for Rb binding, higher cytoadherence was observed in conventional mice only . Taken together, these results indicate that T cells of Lpsd mice express binding site(s) for Salmonella, whereas Lpsn mice have T cells with these structure(s) in a cryptic configuration. Can J Microbiol, 1985 Nov, 31(11), 981 - 7 Isolation and characterization of pyrimidine mutants of Salmonella typhimurium altered in expression of pyrC, pyrD, and pyrE; Kelln RA et al.; Parental strains of Salmonella typhimurium having a specific pyr gene (pyrC, pyrD, or pyrE) fused to the structural genes of the lac operon through the specialized transducing phage Mu dl (ApRlac) were used to construct thermostable derivatives for purposes of conducting a genetic and biochemical characterization of the individual pyr genes . The direction of transcription of each pyr gene in relation to the current linkage map was defined with both pyrC and pyrE being transcribed counterclockwise and pyrD exhibiting clockwise transcription . Mutants displaying increased pyr gene expression were isolated employing a genetic strategy which is of general applicability . Among the mutants, only one isolate was found to possess a mutation which was unlinked to the specific pyr gene under study; the other isolates harbored linked mutations which were inferred to be cis-acting . Additional studies demonstrated that in conditions of severe pyrimidine limitation, further derepression could still o