Evaluation of the mutagenicity of 1,N6-ethenoadenine- and 3,N4-ethenocytosine-nucleosides in Salmonella typhimurium.

To provide supporting evidence for the hypothetical involvement of etheno-derivative formation in DNA in chloroacetaldehyde-mediated mutagenesis, etheno nucleosides were examined for their direct-acting mutagenicity in Salmonella typhimurium strain TA100. The results, however, have shown that 1,N6-ethenoadenosine, 1,N6-ethenodeoxyadenosine, 3,N4-ethenocytidine and 3,N4-ethenodeoxycytidine lack mutagenicity in this test system. A lesson learned in this study is that 3,N4-ethenocytosine nucleosides prepared synthetically or obtained from commercial sources can give false positive mutagenicity due to mutagenic contaminants.