Production of free radicals in DNA and inactivation of its biological activity by gamma-rays
article
The biological significance of damage induced in DNA by ionizing radiation is quantitatively compared with free radical concentration as measured by E.S.R. spectroscopy. Biologically-active DNA of the bacteriophage ΦX174 dried together with carrier DNA was irradiated with γ-rays under vacuum. E.S.R. spectra were recorded at room temperature with a double-cavity spectrometer. After dissolution of the samples the biological activity of the ΦX174 DNA was measured. Absolute spin concentrations were measured with an accuracy of 25 per cent. The G-values for biological inactivation and for production of free spins were 1·3 and 3·2 (± 10 per cent). Inactivation curves were exponential up to at least 5 Mrads; radical concentration, however, became saturated at about 2 Mrads. Cysteamine protected to the same extent against inactivation and free spins.
TNO Identifier
357359
Source
International Journal of Radiation Biology, 17(5), pp. 459-465.
Pages
459-465
Files
To receive the publication files, please send an e-mail request to TNO Repository.