Differential DNA strand breaking abilities of ⋅OH and ROS generating radiomimetic chemicals and γ-rays: Study of plasmid DNA, pMTa4, in vitro

Abstract

Reactive oxygen species (ROS) interact with components of a living cell. Among them ⋅OH is known to cause major oxidative damage to living cells and is proposed to be involved in pathogenesis including carcinogenesis. Proper understanding of consequences of such damage is, therefore, medically relevant. In this report, aqueous solution of plasmid DNA, pMTa4, has been exposed to Fenton oxidant and Haber–Weiss oxidant mediated free radical generating chemical systems, and 60Co γ-rays in vitro either alone or in combination to study their strand breaking abilities. The exposed pMTa4 was analyzed by agarose gel electrophoresis. The results show qualitative differences in the induction of strand breaks on the plasmid pMTa4 molecule by the iron (Fe2+), copper (Cu2+) or γ-rays mediated ⋅OH and other ROS.