Effect of a 50-Hz Magnetic Field on the Degradation of Plasmid in the Presence of Cu(II) Ions and Hydrogen Peroxide

Power-line frequency (50/60 Hz) magnetic fields enhance DNA strand breaks in the cell. In order to understand the molecular mechanism underlying this phenomenon, we analyzed the conversion of plasmid from the supercoiled to the linear form. This conversion is promoted by hydroxyl radical generated by the reaction between Cu 2+ and H 2 O 2 . The plasmid pHSG298 was incubated with 1 mM Cu 2+ and 1 mM H 2 O 2 and exposed to a 1.2 mT, 50-Hz magnetic field for 30, 60, and 90 min. The conversion of supercoiled DNA to linear DNA was analyzed by agarose gel electrophoresis. We found that exposure to the magnetic field for 90 min significantly enhanced the degree of conversion.