Screening for genotoxic activity of amitraz with short-term bacterial assays.

Genotoxic effects of both amitraz and its metabolites made by S9 fraction were reevaluated in short-term bacterial assays. Neither amitraz nor its metabolites induced frameshift mutation or caused base-pair substitution as detected by the Ames test. They also did not introduce any damages into DNA recognized by correndonuclease II as shown by the repair test. Metabolites of amitraz (but not amitraz itself) induced the SOS-repair system in E. coli strain PQ 243 tagA, alkA which was deficient in N-glycosylases. It is concluded that neither amitraz nor its metabolites have mutagenic activity. In contrast to amitraz, its metabolites alkylate DNA in the N3-position of adenine.