Chain Scission of Ribonucleic Acid and Deoxyribonucleic Acid by Ionizing Radiation and Hydrogen Peroxide in Vitro and in Escherichia coli Cells

Publisher Website
Google Scholar
Abstract
A survey was made of the effects of heat, ionizing radiation and H2O2 on DNA and RNA both in vitro and in the living cell. The effects of these agents were observed by using trichloroacetic acid (TCA) precipitation. Because of the value of TCA precipitation in many biochemical and biological studies, an attempt was made to obtain quantitative estimates by this technique. Semiempirical equations to describe the data were derived and calibrated against outside work. The phosphate-potentiating effect on in vitro DNA and RNA scission by H2O2 and ionizing radiation was verified and studied. However, there is no apparent effect on colony-forming ability. While there seems to be no striking pH effect on the action of these agents, their effect is dependent on the chemical nature of the buffer. The reduction.of action in intracellular DNA and RNA, as compared to the in vitro studies, indicates that the cell can modify the effect of such agents. The in vivo work also shows that a large number of scissions can be produced in the cell without apparent radiobiological damage, indicating the existence of an intracellular repair mechanism.