DNA binding and mutagenicity of ethyl methanesulfonate in wild-type and uvrB cells of Salmonella typhimurium.

The extent of DNA ethylation and the influence of excision repair on ethyl methanesulfonate (EMS) mutagenesis of Salmonella typhimurium were examined. The relationship between the dose to DNA and the exposure concentration of EMS was linear. EMS induction of his+ revertants followed exponential kinetics and did not parallel the increase in total DNA ethylation. Mutant induction was influenced by the cells' nucleotide excision repair ability. Although mutagenized to a larger extent than the wild-type (uvr+) strain at high doses, the uvrB strain was more resistant to the mutagenic effect of low doses of EMS.