Quantitative forward mutation assay in Salmonella typhimurium using 8-azaguanine resistance as a genetic marker.

Abstract

A quantitative forward mutation assay using S. typhimurium, in which resistance to the purine analog 8-azaguanine is used as a genetic marker, is developed. The assay protocol, the concentration-dependent toxicity and mutagenicity of 5 known mutagens (N-methyl-N''-nitro-N-nitrosoguanidine, ICR-191 [N-(2-chlorethyl)-N''-(6-chloro-2-methoxy-9-acridinyl)1,3-propanediamine], 9-aminoacridine, dimethylnitrosamine, and benzo[a]pyrene), and reconstruction experiments testing the assay for possible bias. The relative merits of forward vs. reverse mutation assays are discussed.