The effect of ultrasound and its combination with radiation on the genetic material of Saccharomyces cerevisiae.

Ultrasonication at 20 kHz, intensity 35 W/cm2 and amplitude 15--25 micron of a diploid strain of Saccharomyces cerevisiae was found to act as a weak mutagen with maximum efficiency at the 20% survival of the cells. Under these conditions, the frequency of reversion of the suppressible allel ilv1-92 increased ten times, the frequency of mitotic gene conversion four times. Doses leading to survivals lower than 20% led to a slight increase in the frequency of cytoplasmic respiration-deficient mutants. Submutagenic doses applied immediately after gammaradiation or UV light did not substantially increase the effect of these physical agents on the genetic material of the yeast strain investigated. Application of ultrasound prior to UV radiation did not considerably influence the effect of the radiation either.