The Influence of Radiation Quality and Oxygen on Strand Breakage in Dry DNA

Abstract

SummaryDNA isolated from T7 phage or deposits of this phage were irradiated with various qualities of radiation, including track-segment irradiations by charged heavy particles. The amount of single- and double-strand breakage was determined by analysis of the sedimentation boundary in an analytical ultracentrifuge. The results show that(1) a single-strand break is produced on average for each energy-loss event in the DNA molecule(2) an energy-loss event has a chance of about 1 in 20 of producing a double-strand break, with little dependence on LET in the range up to 100 keV/μm(3) there is no significant effect of oxygen on the production of either single-or double-strand breaks.