Physical and chemical mechanisms of DNA damage under the action of various agents

Data on damage to DNA macromolecules by ionizing radiation, ultraviolet light, ultra-sound and chemical mutagens are reviewed. The use of methods involving chemical kinetics and other physico-chemical methods (EPR, chemiluminescence, spin markers, electron microscopy, etc.) to study the mechanism of damage to DNA macromolecules by various agents is considered and the patterns of chemical and structural changes in DNA analysed. The hypothesis regarding the free-radical nature of DNA damage by radiation and the possibility of using radical-reaction inhibitors as radioprotective agents is discussed. Evidence is presented in support of the hypothesis. (author)