PMID: 7012604Nov 1, 1980Paper

The pH-dependent response of Salmonella typhimurium TA100 to mutagenic N-nitrosamines

Mutation Research
T Negishi, H Hayatsu

Abstract

The mutagenicity of some N-nitrosodialkylamines, i.e. N-nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodi-n-butylamine, N-nitrosomorpholine and N-nitrosopyrrolidine, was assayed on Salmonella typhimurium TA100 by the pre-incubation method, and the effect of changing the pH of the pre-incubation mixture was examined. Markedly higher mutagenicities were observed when the pre-incubation of bacteria with nitrosamine and S9 mix was done at pH 5.2, compared with mutagenicities observable after the pre-incubations at conventional pH 7. Pre-incubations at pH 6.2 resulted in responses of intermediate strength. With phenobarbital-induced rat S9, the ratios of mutagenic potency found by the pH 5.2 pre-incubation to that found by the pH 7.2 preincubation were 15-30 for N-nitrosodimethylamine, 5-10 for N-nitrosodiethylamine, 10-20 for N-nitrosodi-n-butylamine, 2-3 for N-nitrosomorpholine and 4-6 for N-nitrosopyrrolidine. The mutagenic potency of each nitrosamine varied with the change of S9 source. The S9 sources examined were PCB-induced rat and mouse livers, and uninduced rat and mouse livers. No exceptions were observed for these S9 preparations regarding the higher mutagenicity at pH 5 than at pH 7. It is speculated that the high...Continue Reading

References

Jan 1, 1979·Mutation Research·T K RaoJ L Epler
Apr 1, 1977·Mutation Research·T YahagiT Sugimura
Dec 1, 1975·Proceedings of the National Academy of Sciences of the United States of America·J McCannB N Ames

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Citations

Jan 1, 1988·Mutation Research·R S LakeE Schwartz
Sep 1, 1987·Food and Chemical Toxicology : an International Journal Published for the British Industrial Biological Research Association·B PignatelliG Descotes
Jan 1, 1989·Free Radical Biology & Medicine·H BartschC Malaveille
Jan 1, 1996·Environmental and Molecular Mutagenesis·H TinwellJ Ashby
Jan 1, 1986·Teratogenesis, Carcinogenesis, and Mutagenesis·M CipollaroG Pagano
Jan 1, 1985·Teratogenesis, Carcinogenesis, and Mutagenesis·G PaganoG G Giordano

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