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

T. Negishi, H. Hayatsu

Research output: Chapter in Book/Report/Conference proceedingChapter

32 Citations (Scopus)

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 pre-incubation 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 higher mutagenicity observed by the pH 5 pre-incubation was due to the stability of the active intermediate, α-hydroxynitrosodialkylamines, in weakly acidic media.

Original languageEnglish
Title of host publicationMutation Research
Pages223-230
Number of pages8
Volume79
Edition3
Publication statusPublished - 1980

Fingerprint

Nitrosamines
Salmonella typhimurium
dibutylnitrosamine
N-Nitrosopyrrolidine
Dimethylnitrosamine
Diethylnitrosamine
Liver
Polychlorinated Biphenyls
Phenobarbital
Bacteria

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Negishi, T., & Hayatsu, H. (1980). The pH-dependent response of Salmonella typhimurium TA100 to mutagenic n-nitrosamines. In Mutation Research (3 ed., Vol. 79, pp. 223-230)

The pH-dependent response of Salmonella typhimurium TA100 to mutagenic n-nitrosamines. / Negishi, T.; Hayatsu, H.

Mutation Research. Vol. 79 3. ed. 1980. p. 223-230.

Research output: Chapter in Book/Report/Conference proceedingChapter

Negishi, T & Hayatsu, H 1980, The pH-dependent response of Salmonella typhimurium TA100 to mutagenic n-nitrosamines. in Mutation Research. 3 edn, vol. 79, pp. 223-230.
Negishi T, Hayatsu H. The pH-dependent response of Salmonella typhimurium TA100 to mutagenic n-nitrosamines. In Mutation Research. 3 ed. Vol. 79. 1980. p. 223-230
Negishi, T. ; Hayatsu, H. / The pH-dependent response of Salmonella typhimurium TA100 to mutagenic n-nitrosamines. Mutation Research. Vol. 79 3. ed. 1980. pp. 223-230
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