Mutagenicity tests with a permeable mutant of yeast on carcinogens showing false-negative in Salmonella assay.
The mutagenicity (Trp+ reversion) of procarcinogens such as N-nitrosodimethylamine, 3,4-benzpyrene and 2-acetylaminofluorene has been detected with the permeable mutant of yeast, Saccharomyces cerevisiae C658-K42. The original strain C658, however, showed a positive response only to N-nitrosodimethylamine with S9 mix. The permeable mutant C658-K42 was employed for mutagenicity tests on 12 carcinogens which had been reported to be non-mutagenic in Salmonella/microsome tests. It was found that phenobarbital, thiourea, 1,2-dimethylhydrazine and 4-aminoantipyrine were mutagenic in the presence of S9 mix. Benzene, o-toluidine and thioacetamide were weakly mutagenic. Negative results were obtained for diethylstilbestrol, safrole, acetamide, urethane and ethionine at the concentrations used. Caprolactam did not show any mutagenic effect on C658-K42 at concentrations up to 20 mg/ml. Sodium azide, which is unlikely to be carcinogenic but is strongly mutagenic in the Ames test, showed a very weak mutagenic effect on C658-K42.
Morita
T
T
Iwamoto
Y
Y
Shimizu
T
T
Masuzawa
T
T
Yanagihara
Y
Y
D000818:Animals; D002273:Carcinogens / Q000633:toxicity*; D066298:In Vitro Techniques; D009152:Mutagenicity Tests; D009153:Mutagens; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D012486:Salmonella typhimurium / Q000235:genetics
D002273:Carcinogens; D009153:Mutagens