Abstract

The effect of (20 kHz continuous wave) ultrasound (power from 17 to 77 W) on the damage of nitrogen bases, the loss of double-helical structure, strand breaks and fragmentation of Calf spleen DNA were studied in vitro. The relative ultrasound sensitivity of the hydrogen bonded base pairs A-T and G-C were also studied. The techniques used in this investigation were ultraviolet absorption spectroscopy and constant-field gel electrophoresis (CFGE). The results showed that ultrasound decreased the hydrogen-bonded nucleotides. The ultrasound sensitivity was greater for the A-T base pairs than for the G-C base pairs. It was also shown that high power ultrasound damaged the nitrogen bases. The loss of the double helical structure by the ultrasound was mainly due to the separation of certain sections of the DNA by single strand breaks (SSB) and also to a small extent due to base damage. The size of the DNA fragments decreased as the ultrasound power increased and finally a plateau effect was seen at the highest powers.         

Key words: DNA damage, ultrasound, spectroscopy.