[Oxygen effect in the radioresistant Escherichia coli Gamr444 strain]

In experiments on E. coli Gamr 444 the oxygen effect has been studied. Cells were exposed to gamma-rays with constant bubbling of oxygen or nitrogen through the suspension or without bubbling. In the latter case the dose-effect curve was distorted due to radiochemical absorption of oxygen. The dose curve parameters were determined in the anoxic and oxygenating conditions, they are: lin n(N2) = 3.6; D0(N2) = 371 Gy; In n(O2) = 3.6; D0(O2) = 112 Gy. The oxygen effect for E. coli Gamr 444 was 3.3 as determined by D0. In studying the radiosensitivity and its modification in radioresistant strains one should eliminate the influence of radiochemical absorption of oxygen by aeration of the medium during exposure.