INDUCTION OF MUTATIONS IN TRANSFORMING DNA BY HYDROXYLAMINE

Abstract

Prototroph transforming DNA of B. subtilis were treated with hydroxylamine (HA), and the resultant induction of mutations was determined. It was found that mutagenic reactivity of DNA bases was greatly increased when the strands were partially or completely separated. While the frequency of forward mutations increased when undenatured DNA was treated with HA, the titer decreased at high temperatures even in the absence of HA. It was also found that the mutation rate increased almost linearly with HA concentration, and with decreasing NaCl concentration and decreasing pH; in addition, the mutation rate greatly decreased with increasing ionic concentration, and there was a drastic increase of this mutation rate with the concentration of glycol. The mutation rate also abruptly increased when the temperature was raised above the melting temperature. There was also an increase in mutation rate when heat denatured DNA was treated at lower temperatures and then renatured.