Frameshift mutagenicity of dinitrobenzene derivatives on Salmonella typhimurium TA98 and Tm elevation of calf thymus DNA by dinitrobenzene derivatives

1-Chloro-2,4-dinitrobenzene and m-dinitrobenzene were mutagenic on Salmonella typhimurium TA98 without S-9mix. But 1-substituted-2,4-dinitrobenzene derivatives which substituted by electron releasing groups such as OH-, NH2- or CH3- did not show mutagenicity on Salmonella typhimurium TA98 without S-9mix. Tm of calf thymus DNA was elevated by addition of m-dinitrobenzene or 1-chloro-2,4-dinitrobenzene, and falled by addition of 1-substituted-2,4-dinitrobenzenes which substituted by electron releasing substituents such as OH-, NH2- or CH3- groups. The mutagenic dinitrobenzene derivatives such as 1-chloro-2,4-dinitrobenzene showed the special changes in the difference spectra about four bases of the DNA and this compound.