[Mutagenic action of O-methlhydroxylamide on transforming DNA]

The mutagenic effect of O-methylhydroxylamine (OMHA) on transforming DNA of Bacillus subtilis was studied. In accordance with the earlier reported chemical and functional data, the mutagenic effect was observed at 4.5 and 6.0 pH. An increase in pH caused a decrease in the rate of mutagenesis, though the maximal level of mutagenesis was equal at both values of pH. The results obtained with recipients defective in the system of UV-repair revealed that both products of reaction of OMHA with the cytosine-base of DNA, N4-metoxycytidine and N4-metoxy-6-metoxyamino-5,6-dihydrocytidine, are effectively eliminated through the system of UV repair.