Genotoxicity of methyl parathion in short‐term bacterial test systems

Abstract

Genotoxicity of the inseciticide methyl parathion was investigated in Salmonella typhimurium and Escherichia coli bacterial test systems for the detection of back mutations and DNA damage. Methyl parathion was mutagenic to S. typhimurium strain TA100 after activation with rat liver microsomal and cytosolic enzymes. In DNA repair tests, methyl parathion was effective in inducing damage to the S. typhimurium strain TA1538 which lacked excision repair compared to the strain TA1978 which was proficient in excision repair mechanisms. Normal laboratory light conditions had no effect on the mutagenicity tests; exposure of methyl parathion in the petri dish containing the tester strain TA100 and rat liver microsomal and cytosolic enzymes reduced the mutagenic activity and increased the toxic effects of methyl parathion.