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Mutagenicity of cyclic nitrosamines in Salmonella typhimurium: effect of ring size
Abstract:
Mutagenicity of cyclic nitrosamines with varying carcinogenic potentials was assayed in the Salmonella histidine-reversion system. Mutagenicity in the pour-plate assay was compared with that in the liquid pre-incubation test. The smaller ring compounds (nitrosoazetidine, nitrosopyrrolidine, and nitrosopiperidine) exhibited a similar effect in both assays. The large ring compounds (nitrosohexamethyleneimine, nitrosoheptamethyleneimine, nitrosooctamethyleneimine, and nitrosododecamethyleneimine) were more effective in the liquid pre-incubation test. Our results suggest a reasonable relationship between their mutagenic and carcinogenic activities.
Insights
Cyclic nitrosamines were tested for mutagenicity using the Salmonella histidine-reversion assay. Larger ring compounds showed higher mutagenicity in liquid pre-incubation tests, suggesting a link between mutagenic and carcinogenic activities.
Area of Science:
- Toxicology
- Chemical Carcinogenesis
- Microbial Genetics
Background:
- Cyclic nitrosamines are a class of chemical compounds known to possess varying carcinogenic potentials.
- Assessing the mutagenic activity of these compounds is crucial for understanding their potential health risks.
- The Salmonella histidine-reversion system is a widely used tool for mutagenicity testing.
Purpose of the Study:
- To evaluate the mutagenicity of cyclic nitrosamines with different carcinogenic potentials.
- To compare the effectiveness of two different assay methods: the pour-plate assay and the liquid pre-incubation test.
- To explore the relationship between the mutagenic activity and carcinogenic potential of these compounds.
Main Methods:
- Cyclic nitrosamines were subjected to mutagenicity assays using the Salmonella histidine-reversion system.
- Mutagenicity was assessed using both the pour-plate assay and the liquid pre-incubation test.
- The results from both assay methods were compared for various cyclic nitrosamine compounds.
Main Results:
- Smaller ring cyclic nitrosamines (nitrosoazetidine, nitrosopyrrolidine, nitrosopiperidine) showed similar mutagenicity in both assay methods.
- Larger ring cyclic nitrosamines (nitrosohexamethyleneimine, nitrosoheptamethyleneimine, nitrosooctamethyleneimine, nitrosododecamethyleneimine) were more mutagenic in the liquid pre-incubation test.
- A correlation was observed between the mutagenic activity and the known carcinogenic potentials of the tested compounds.
Conclusions:
- The choice of assay method can influence the observed mutagenicity of cyclic nitrosamines, particularly for larger ring compounds.
- The liquid pre-incubation test appears to be more sensitive for detecting the mutagenicity of certain cyclic nitrosamines.
- The study supports a reasonable relationship between the mutagenic and carcinogenic activities of cyclic nitrosamines, aiding in risk assessment.