Metabolic activation and inactivation of metanil yellow and orange II in the Salmonella typhimurium his- reversion assay

Abstract

Among a variety of experimental protocols used, ihe combined use of 0.5% dextrose in bottom agar and 1 μm of flavin mononucleoudc (FMN) in preincubation mixtures without fraction S9 mix resulted in me highest level of induced Salmonella typkimurium his- reversions with both dyes metanil yellow and orange II with strain TA100. Strain TA98 yielded notably lower levels of reversions under the same conditions. The presence of uninduced hamster liver S9 fraction resulted in a weak mutagenic responce while Aroclor 1254-induced rat liver S9 fraction resulted in ihe complete absence of mutagenicity with both strains and with both dyes.