A search for Saccharomyces cerevisiae mutants with an increased sensitivity to nitrous acid.

Six strains with an increased nitrous acid sensitivity were isolated (Fig. 1). The putative HNO2-sensitive mutants, as well as the parental strain 55R5 behaved abnormally in crosses, so that studies on the segregation of the sensitivity were difficult and unreliable. During 1.5 years the oversensitivity of the mutants gradually decreased to disappear completely (Tab. V). The differences in HNO2 sensitivity between respiratory-sufficient and cytoplasmic respiratory-deficient strains (Tab. I), as well as between different respiratory-sufficient strains (Tab. II-IV) are analysed.