The influence of methyl substitution of the mutagenicity of nitronaphthalenes and nitrobiphenyls.

A series of nitrobiphenyls, nitronaphthalenes, and their methyl-substituted derivatives were assayed for mutagenicity toward S. typhimurium TA98 and TA100. In assays conducted in the absence of rat liver S9 fraction, substitution of a methyl group ortho to the nitro group decreased mutagenicity (3-methyl-4-nitrobiphenyl, 2-methyl-1-nitronaphthalene, and 3-methyl-2-nitronaphthalene).

Mutagenicity of aminophenyl and nitrophenyl ethers, sulfides, and disulfides.

The mutagenic activity of several aromatic amines and aromatic nitro compounds related to 4,4'-methylenedianiline towards Salmonella typhymurium tester strains TA100 and TA98 was evaluated. The heteroatomic analogs of 4,4'-methylenedianiline which include aminophenyl and nitrophenyl ethers, sulfides and disulfides were assayed in the presence of rat-liver homogenate. The relative mutagenic response of these analogs indicated the following order of activity, --S-- greater than --O-- greater than --CH2--CH2-- greater than or equal to --S--S--.