title: [Effect of O-hydroxylamine on the transforming DNA from Bacillus subtilis. Correlation of chemical modifications with genetic consequences].
abstract: The action of methoxyamine (MA) on B. subtilis transforming DNA (50 degrees C, pH 4,5 and 6,0, 1 M MA) was studied. The rate of cytosine residues modification in DNA is 250 times less than in monomer (rate constants for DNA are 1,5 X 10(-1) min-1 at pH 4,5, and 2,5 X 10(-6) min-1 in the first 300 hours of treatment at pH 6,0). At pH 4,5 the rates of cytosine (I) conversion into N4-methoxycytosine (II) and into 6-methoxyamino-5,6-dihydro-N4-methoxycytosine (III) are constant (II/III ratio is about 2,1). At pH 6,0 the II/III ratio smoothly increases from 1,0 to 1,6 (200 and 900 hours of treatment) due to a decrease in the product III accumulation rate. The frequency of MA-induced mutations shows a bell-shaped dependence on time with maxima (approximately 10%) at 80 (pH 4,5) and 500 (pH 6,0) hours of treatment. In both cases approximately 10% of cytosine residues are modified. These results suggest that either compound III is efficiently removed from the transforming DNA, or its presence does not arrest the DNA replication.
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics*; D001482:Base Composition / Q000187:drug effects; D004269:DNA, Bacterial / Q000235:genetics*; D019811:Hydroxylamine; D006898:Hydroxylamines / Q000494:pharmacology*; D009154:Mutation; D014169:Transformation, Bacterial / Q000187:drug effects*
chemical_list: D004269:DNA, Bacterial; D006898:Hydroxylamines; D019811:Hydroxylamine
vernacular_title: Deĭstvie O-metilgidroksilamina na transformiruiushchuiu DNK Bacillus subtilis. Korreliatsiia khimicheskikh izmeneniĭ s geneticheskimi posledstviiami.