| Abstract: | Solutions of nucleic acid bases, nucleosides and a nucleotide, saturated with either N2, N2O or O2, were irradiated and tested for mutagenicity towards Salmonella typhimurium, with and without pre-incubation. Irradiated solutions of the nucleic acid bases were all non-mutagenic. Irradiated solutions of the nucleosides showed mutagenicity in S. typhimurium TA100 (pre-incubation assay). Generally, the mutagenicity followed the order: N2O greater than N2 greater than O2. The results show that the formation of mutagenic radiolytic products is initiated by attack of mainly OH radicals on the 2-deoxy-D-ribose moiety of the nucleosides. With irradiated solutions of the nucleotide, thymidine-5'-monophosphate, no mutagenicity could be detected. |
