INDUCTION OF GENE MUTATIONS AND GENE CONVERSIONS BY VINYL-CHLORIDE METABOLITES IN YEAST

Abstract

Chloroethylene oxide and 2-chloroacetaldehyde, 2 metabolites of vinyl chloride, and 2-chloroethanol, a putative metabolic intermediate, were assayed for their genetic activity in the yeasts Schizosaccharomyces pombe and Saccharomyces cerevisiae. Chloroethylene oxide was the most effective in inducing forward mutations in S. pombe and gene conversions in S. cerevisiae, increasing the mutation and conversion frequencies 340 and 50 times, respectively, over those of the controls. In the presence or absence of mouse liver microsomes, 2-chloroacetaldehyde showed only feeble genetic activity, and 2-chloroethanol was completely inactive in both yeast strains. In contrast to vinyl chloride, 2-chloroacetaldehyde did not induce forward mutations in S. pombe in the host mediated assay in mice. The results support the hypothesis that chloroethylene oxide is 1 of the principal mutagenic agents formed from vinyl chloride in the presence of mouse liver enzymes.