The Effect of Oxygen on DNA Single-strand Breaks Produced by Ionizing Radiation in Mammalian Cells

Summary

Mouse L-60 cells were irradiated in O₂ or N₂ atmospheres, and DNA single-strand breaks were measured using alkaline sucrose gradients. It was found that the presence of oxygen increased the yield of single-strand breaks. The oxygen enhancement ratio (OER) was 2·9, a value comparable to the OER for its colony-forming ability in L-60 cells. This observation was made using two different sedimentation techniques.