Mutagenic action of nitrous acid on Aspergillus nidulans

Abstract

Nitrous acid is shown to be a potent killing and mutagenic agent for Aspergillus nidulans. The kinetics of mutation rates induced by nitrous acid are investigated by means of three phenotypically distinguishable suppressors of methionine requirement. The dose-effect curves for two of the suppressors are non-linear. Among w and y mutants produced by nitrous acid there is a high proportion of sectored mutants. Double screening experiments indicate that at least some of the sectored mutations may be due to the presence of more than one genetic strand at the time of treatment. Two of the suppressor genes respond differentially to nitrous acid treatment.