Macromolecular Repair and Free Radical Scavenging in the Protection of Bacteria against X-Rays

Abstract

Among the substances that modify the effects of X-rays on cells are oxygen (1-3), nitric oxide (4-7), N-ethylmaleimide (8), sulfhydryls (9-15), and alcohols (1619). To explain the actions of these substances, several authors have suggested hypothetical reaction schemes for the events leading to the formation of injuries in vital macromolecules within the cell (20-24). Similarly, experiments on the survival of the biological activity of X-irradiated bacteriophage under a wide range of sulfhydryl concentrations have led to the formulation of a reaction scheme for the X-ray injury to phage DNA (25), which, in a simplified form, is as follows: