The mutagenicity of sodium bisulfite on base‐substitution strains ofSalmonella typhimurium

摘要

AbstractThe mutagenic effects of sodium bisulfite onSalmonella typhimuriumLT2 strains carrying thehisG46allele were investigated. Treating the cells with 1 M sodium bisulfite in 0.2 M acetate buffer (pH 5.2) for various time intervals at 37°C resulted in an increase in the yield of mutants above the spontaneous level. The fold enhancement of the mutant yield and the fold enhancement of the mutant frequency were greatest for the parent strainhisG46with wild type DNA repair; the derived strains with reduced repair capacity responded to a lesser degree. While sodium bisulfite was mutagenic when tested in liquid suspension assays, strainhisG46did not respond when the standard Ames plate incorporation assay was used. The greater mutagenic response in repair‐proficient strains suggests that normal repair capacities may favor the mutagenic activity of sodium bisulfite. Transduction studies demonstrated that mutations ofhis+were closely linked to thehisDgene, and probably were in the structuralhisGgene itse