Mutations in Salmonella typhimurium

The results on the cellular protection against N()2 can be interpreted as the N()2 reacting with the three antioxidants to produce their radicals, with ascorbic acid reacting least efficiently, probably due to the lower reduction potential of its radical. Moreover, Arroyo et al. (1992) reported that NO - and N02 -induced mutations in Salmonella typhimurium TA1535 were inhibited efficiently by P-CAR and tocopherols, but not at all by ascorbic acid. 

NIOSH has classified chromyl chloride as an inferred carcinogen based on sufficient evidence of carcinogenicity in humans for chromium and other chromium compounds. Chromyl chloride elicited dose-related mutations in Salmonella typhimurium. ... 

Safety of Enterosgel preparation in terms of mutagenic action has been shown in the tests for induction of chromosome aberrations in bone marrow cells, in cultured human peripheral blood lymphocytes, and in the Ames test for induction of reversible gene mutations in Salmonella typhimurium. 

Catechol did not induce gene mutations in Salmonella typhimurium or DNA repair in a mouse host-mediated assay in Escherichia coli. 

Unless otherwise indicated, studies were carried out with an 80/20 mixture of 2,4/2,6-toluene diisocyanates. In one of two studies, toluene diisocyanate induced mutations in Salmonella typhimurium strains TAIOO, TAI 538, and TA98 in the presence of an exogenous metabolic activation system only. It induced sex-linked recessive lethal mutations in Drosophila in a single study. 

Vinylidene chloride induced mutations in Salmonella typhimurium and Escherichia... 

Chloro-1,1,1-trifluoroethane did not induce mutations in Salmonella typhimurium (lARC, 1986). 2-Chloro-1,1,1-trifluoroethane was reviewed by a WHO task group, which also concluded that it did not induce mutations in S. typhimurium, but additionally that it did not induce chromosomal aberrations in rat bone-marrow cells in vivo. Dominant lethal effects were observed in two of three studies in male mice (WHO, 1992). 

Ames Test The Ames test, developed by Bruce Ames and his coworkers at the University of California, Berkeley, depends on the ability of mutagenic chemicals to bring about reverse mutations in Salmonella typhimurium strains that have defects in the histidine biosynthesis pathway. These strains will not grow in the absence of histidine but can be caused to mutate back to the wild type, which can synthesize histidine and hence can grow in its absence. The postmitochondrial supernatant (S-9 fraction), obtained from homogenates of livers of rats previously treated with PCBs in order to induce certain cytochrome P450 isoforms, is also included in order to provide the activating enzymes involved in the production of the potent electrophiles often involved in the toxicity of chemicals to animals. 

As indicated in Table 2-4, 2-nitrophenol did not increase the frequency of reverse mutations in Salmonella typhimurium or in Escherichia coli in the presence or absence of metabolic activation, nor did it induce DNA damage when tested in Bacillus subtilis. No data were available regarding genotoxic properties of 2-nitrophenol in eukaryotic organisms. 

Figure 4. Biosynthetic pathway from chorismate to enterobactin showing nature of the class I and class II mutations in Salmonella typhimurium LT-2...

Sodium fluoride did not induce reverse mutations in Salmonella typhimurium, nor did it induce gene conversion in Saccharomyces cerevisiae. A fluoride level of 0.4-1.0mgl inhibited DNA repair after irradiation of mouse spleen cells in vitro. Sodium fluoride was not mutagenic in cell cultures of human leukocytes at concentrations of 18 and 54mgl . Little or no effect was noted on chromosomes when mouse oocytes were exposed in vitro to a fluoride concentration of 200 mg 1 in media for up to 14 h. 

For mutagenic activity, the risk of carcinogens and mutagens compounds which might be presented in the oil was also evaluated according to the international guidelines (OECD 471 and commission directive N° B13/14). Tests have been conducted at the CIT (International Center of Toxicity) Safety and Health Research Laboratories, 27005 Evreux, France. This test evaluates the potential of the Saro essential oil to induce reverse mutation in Salmonella typhimurium, knowing that the bacterial reverse test is able to identify substances that cause point mutations, by affections of DNA base-pairs (19, 20). Five strains of S. typhimurium TA 1535, TA 1537, TA 98 TA 100 and TA 102 were supplied for the study by B.N. Ames Laboratory (University of California, Berkeley or Oakland Research Institute, USA). 

Vaatanen AK et al., Spectrum of spontaneous and 2,4,6-trinitrotoluene (TNT)-induced mutations in Salmonella typhimurium strains with different nitroreductase and O-acetyltransferase activities, Mut. Res., 379, 185, 1997. 

NO is a mutagenic compound that can cause mutations in Salmonella typhimurium bacteria (Arroyo et al., 1992) as well as induce mutations and chromosomal aberrations in rat primary lung cells exposed to doses of NO below 100 ppm for a few hours (Isomura et al., 1984). Some of this effect might be due to the formation of NO2 in the exposure chamber. Cigarette smoking causes lung cancer, and chronic inhalation exposure to the oxides of nitrogen may contribute to this effect. 

Reverse mutation in Salmonella typhimurium strains TA1535, TA1537, TA1538, and TA100 (Ames). 

Zhao, R.B., Schuster, S.C. and Khan, S. (1995). Structural effects of mutations in Salmonella typhimurium flagellar switch complex./. Mol. Biol. 251, 400-412. 

Sulfur mustard has been found to be genotoxic and mutagenic in several microbial assays. The agent caused alkylation of DNA in the yeast Saccharo-myces cerevisiae (Kircher and Brendel 1983) and interstrand DNA cross-links (Venitt 1968) and inhibition of DNA synthesis (Lawley and Brookes 1965) in Escherichia coli. Using the histidine reversion assay, Stewart et al. (1989a) found that sulfur mustard induced point mutations in Salmonella typhimurium strain TA102 and frameshift mutations in TA 97 but neither type of mutation in strains TA98 and TAIOO. 

Isometamidium resulted in frameshift mutations in Salmonella typhimurium strains TA 1537, TA 1538 and TA 98 in the presence of metabolic activation. 

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