The Effect of Oxygen during Irradiation on the Uptake of Phosphorus and Sulfur by Irradiated Cells of Escherichia coli

Abstract

The effect of irradiating cells of Escherichia coli bubbled with nitrogen or oxygen during exposure to gamma-radiation on the uptake of phosphate and sulfate has been measured. The effect of radiation is to cause a transition, at a later time, to linear uptake as opposed to exponential in the controls. The presence of oxygen shortens the time of transition to the linear phase and also diminishes the rate of uptake when the linear phase "begins. The reduction of dose for the time of onset of linear uptake is 1.9 for phosphate and 2.0 for sulfate. The equivalent figure for the effect on rates of uptake is between 2 and 3. For the formation of colonies it was 1.87.