title: DNA-damaging and mutagenic effects of 1,2-dimethylhydrazine on Bacillus subtilis repair-deficient mutants.
abstract: Mutagenic, DNA-damaging, and in vivo alteration of DNA have been demonstrated for 1,2-dimethylhydrazine (DMH), a potent inducer of adenocarcinomas of the large intestine and colon of rats. These activities are pH-dependent, with 6.5 giving optimum response. There was no requirement for metabolic activation with rat-liver S9 mix when the appropriate Bacillus subtilis mutant strains were used. The Rec- strains recA8 and mc-1 were greater than 300-fold more sensitive to the DNA-damaging activity of DMH than was their isogenic wild-type parent. The DNA isolated from DMH-treated mc-1 had altered spectroscopic characteristics, and gave a greatly reduced transformation efficiency. Treatment of B. subtilis strain TKJ6321 with DMH at pH 6.5 induced His+, Met+ mutations in substantial numbers at low concentrations of this chemical. The use of B. subtilis mutants in these studies has therefore made it possible to demonstrate mutagenic and DNA-damaging activity in bacteria for this potent carcinogenic chemical.
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics*; D004260:DNA Repair; D004269:DNA, Bacterial / Q000235:genetics*; D004127:Dimethylhydrazines / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D008763:Methylhydrazines / Q000494:pharmacology*; D009153:Mutagens; D009690:Nucleic Acid Conformation; D010641:Phenotype; D013053:Spectrophotometry
chemical_list: D004269:DNA, Bacterial; D004127:Dimethylhydrazines; D008763:Methylhydrazines; D009153:Mutagens