Influence of X Irradiation on Potassium Retentivity by Escherichia coli. ∗

Abstract

Summary

1) Potassium efflux from stationary-phase cells of Escherichia coli takes place readily in the presence of ammonium ions. Hence, through the use of ammonium phosphate buffer, K⁺ efflux was studied at a set value of pH. Sodium ions, on the other hand, retard K⁺ efflux, a finding that has been used to advantage when sodium phosphate is used as buffer in delaying efflux measurement. 2) Potassium efflux from E. coli increases as a result of X irradiation. Amount of X-ray damage to K⁺ retention mechanism varies inversely with cell concentration during irradiation. E. coli strain B is much more susceptible to this radiation damage than is its mutant B/r.