A straight correlation between mutagenic activity and β-galactosidase activity induced by monofunctional alkylating agents

Eight monofunctional alkylating agents were examiend for their ability to induce mutationa in Salmonella typhimurium. The assay was carried out in S. typhimurium TA100 with the preincubation method. The SN1-type agents were more mutagenic than the SN2-type ones; besides, methylating agents exerted more mutagenic activity than ethylating ones. Those responses in the revesion assay were quite similar to the results obtained previously with the β-galactosidase assay in Escherichia coli CSH26/pMCP100 (alkA'-lacz') as to the induction of the adaptive response. A good correlation was found between mutagenic potency in the reverse mutation assay and inducing potency in the β-galactosidase assay.