Intracellular generation of reactive oxygen species and DNA damage in Escherichia coli mutants exposed to electromagnetic field and X-ray

In order to examine intracellular generation of reactive oxygen species (RO S) and DNA damage in bacterial cells exposed to extremely low frequency mag netic Held (ELFMF) at 400mT and 50Hz and X-ray, 'kat-sod Assay' and 'rec-la c Assay' were performed using E. coli mutants which were deficient in ROS s cavenging enzymes, such as superoxide dismutase and/or catalase, and DNA re pair capacities. Both assays were developed by Nishioka H. and Hayashi S. ( 1995) and Nunoshiba T. and Nishioka H. (1991) and consisted of survival tes t and beta-galactosidase test. X-irradiation induced a clear intracellular generation of ROS and DNA damage, indicating a possibility that intracellul ar generated ROS may play a partial role in DNA damage by X-ray. On the oth er hand, no remarkable effects of ELFMF were seen in the cells using by 'ka tsod Assay' and 'rec-lac Assay', showing that ELFMF did not generate ROS in tracellularly and damage DNA.