Absence of mutation following ultrasonic treatment of Bacillus subtilis cells and transforming deoxyribonucleic acid.

Possible mutagenic effects of ultrasound at medical dosages have been assessed using genetic systems of Bacillus subtilis. The induction of mutations, after treatment of cells and of extracted transforming DNA with ultrasound has been tested. High-frequency (2 MHz diagnostic regime and higher intensities) ultrasound was unable to increase significantly the spontaneous frequency of back-mutation of an auxotrophic strain. Moreover, high-frequency treatments (1.5 MHz diagnostic and therapeutic regimes) were incapable of producing detectable levels of mutagenic lesions after in vitro irradiation of transforming DNA. Slight decreases in transforming activity of the treated DNA were apparent while the degree of linkage between two contiguous markers was unaffected. It is concluded that the ultrasound treatments employed under the conditions pertaining do not result in production of detectable mutagenic effects in cells or in vitro treated DNA. Before extrapolating such results to the human hazard situation, it is suggested that tests using genetic systems of higher organisms should be carried out.