The Sensitization of Ascospores to Chemical Activators by Heat Treatment

SUMMARY

Short exposures of ascospores of Neurospora tetrasperma to temperatures between 38°–50° C have been shown to increase the activating effect of furfural. 28-month-old ascospores, as well as more recently harvested ones, respond to such treatment. The activating effect of chemical activators other than furfural has also been shown to be enhanced by heat-treatment. Aerobic incubation of heat-treated ascospores causes a rapid loss in sensitivity to furfural. On the other hand, such sensitivity is retained for longer periods of time under conditions where oxygen is limiting. A 2–3-fold increase in respiratory rate accompanies heat-sensitization but does not seem to be the cause of such sensitization.