S. typhimurium strain

Thiamine was biosynthesized by resting cells of S. typhimurium strain thilO/T-ath-383, which can synthesize thiamine from exogenous glucose, AIRs, and thiazole.54 Derepression was achieved by conventional means. The organism was cultivated in the presence of a suboptimal amount of thiamine (20 nM), the washed cells were resuspended in a minimal medium containing glucose (10 mM), thiazole (1-2 mM), and labeled AIRs (10 p,M). During the incubation (1.5 hours 37°C), the level of thiamine diphosphate in the cells had risen from about 0.04 to 0.5 nmol/mg. In work with molecules labeled with stable isotopes, thiamine was extracted and cleaved by ethanethiol to 4-amino-5-(ethyl-... 

Mutagenicity of tetrahydroepoxides. The mutagenic activity, without metabolic activation, of fourteen PAH tetrahydroepoxides has been measured in S. typhimurium strain TA 100. The logarithms of the relative mutagenic activities are plotted in Figure 3 vs. the value of AEj / calculated for conversion of each tetrahydro-... 

Mutagenicity of diol epoxides. The intrinsic mutagenicities of ten diol epoxides-1 and twelve diol epoxides-2 toward S. typhimurium strain TA 100 and Chinese hamster V79 cells have been determined (14,28,29). For diol epoxides-1, the logarithms of the relative mutagenicities vs. the calculated values of AE(je oc/8 are given in... 

The mutagenicities of the bay region diol epoxides derived from BA, BaAcr and BcAcr toward S. typhimurium strain TA 100 (similar results are obtained in strain TA 98) and Chinese hamster V79 cells... 

Recently, Bryant t al. (70) examined the metabolism of 1,8-dinitropyrene in several S. typhimurium strains and found reduction to l-amino-8-nitropyrene and 1,8-diaminopyrene. In addition, other unidentified metabolites were detected in strains which were sensitive to 1,8-dinitropyrene-induced mutations (TA98 and TA98NR) but not in the resistant strains, TA98/1,8-DNP and TA98NR/1,8-DNP6. 

Figure 3. Mutagenic activities of the promutagens cis- and Xrms-diallate and sulfallate, the proximate mutagen cis-diallate sulfoxide, and the ultimate mutagen 2-chloroacrolein, assayed with S. typhimurium strain TA 100 sensitive to base-pair substitution mutagens. The diallate isomers and sulfallate are not mutagenic without the S9 mix. S9 mix refers to a microsomal oxidase system prepared from rat liver and appropriate cofactors. The methodology is detailed in Refs. 6, 22, and 29.

Three putative metabolites of di(2-ethylhexyl) adipate—(mono(2-ethylhexyl) adipate, mono(2-ethyl-5-hydroxyhexyl) adipate and mono(2-ethyl-5-oxohexyl) adipate)—were not mutagenic to S. typhimurium strains TAIOO, TA102, TA98 or TA97 in the presence or absence of exogenous metabolic activation. 

Eder, E., Deininger, C. Wiedenmann, M. (1989) Methyl methanesulphonate (MMS) is clearly mutagenic in S. typhimurium strain TA1535 a comparison with strain TAIOO. Mutat. Res., 226, 145-149... 

Bartsch, H., Malaveille, C., Camus, A.-M., Martel-Planche, G, Brun, G, Hautefeuille, A., Sabadie, N., Barbin, A., Kuroki, T., Drevon, C., Piccoli, C. Montesano, R. (1980) Validation and comparative studies on 180 chemicals with S. typhimurium strains and V79 Chinese hamster cells in the presence of various metabolizing systems. Mutat. Res., lb. 1-50... 

Figure 1. Ames assay dose-response curves of the mutagenic effects of 25-, 50-, and 100-pL aliquots of nitrosated fru-trp reaction mixture and controls on S. typhimurium strains TA98 (top) and TA100 (bottom). Bacteria and test mixtures were preincubated with and without S-9 mix for 20 min at 37 °C. Background revertant levels were not subtracted from the data points shown.

The di-, tri-, and sulfallates were classified as potent mutagens in the Ames assay with TA 100 and TA 1538 (base-pair substitution mutants), with metabolic activation required (1978). More recent in vitro testing (1981) of di- and triallate with S. typhimurium (strains TA1535.-100, and -98) showed dose-related increases without metabolic activation, but greatly enhanced mutagenicities in the presence of Aroclor 1254-induced rat liver S-9 fraction. These tests indicated that both the di- and triallates can induce base pair substitution and frame shift mutations. 

Bartsch H, Malaveille C, Camus AM, et al. 1980. Validation and comparative studies on 180 chemicals with S. typhimurium strains and V79 Chinese hamster cells in the presence of various metabolizing systems. Mutat Res 76 1-50. 

Tests for gene mutations have been mixed, both in vivo and in vitro. Asbestos fibers were not mutagenic in initial tests of standard strains of Salmonella typhimurium and Escherichia coli (Chamberlin and Tarmy 1977), but mutagenic responses were found in a S. typhimurium strain, TA102, that is especially sensitive to oxidative mutagens (Faux et al. 1994). 

Diaminophenol was reported to be mutagenic only with activation in S. typhimurium strain TA1538 (Dybing and Thorgeirsson 1977). Another report (Kawai eta 1. 1987) stated that 2,4-diaminophenol was mutagenic, but did not produce further information. 

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