Turkish Journal of Biology

Abstract: The protective effects of a-keto acids on the mutagenicity of H₂O₂ and NaN₃ was investigated in Salmonella typhimurium TA 98, TA 100, TA 102. H₂O₂ (340 µg/plate) was mutagenic to the strains TA 98 and TA 102 while NaN₃ (1.5 µg/plate) was mutagenic only to TA100. The extents of protective effect of pyruvate (220-440 µg/plate) and a-keto glutarate (335-600 µg/plate) against H₂O₂ were observed to be 37%- 65% in TA 98 and TA 102. a-keto acids were ineffective against NaN₃ induced mutagenicity in TA 100. H₂O₂ (340 µg/plate), in the presence of NaN₃ (1.5 µg/plate) and a-keto acids (330-500 µg/plate), was found to be nonmutagenic to the strain TA102. This cross-adaptive response might have been due to the intactness of the DNA repair system in TA 102. The above combination of H₂O₂, NaN₃ and a-keto acids were found to be cytotoxic in TA 98 and TA 100, possibly because these strains carry uvr B mutation causing defect in their DNA repair system.

Key Words: a-keto acids, H₂O₂, NaN₃, Ames test system, mutagenicity, antimutagenicity