Glucose-induced Resistance to Gamma-rays inEscherichia Coli

SummarySome strains of Escherichia coli, when grown to stationary phase in nutrient broth which has been enriched with glucose, become more resistant to radiation (glucose-induced resistance, GIR) than when grown in nutrient broth without glucose. Various repair-deficient strains of E. coli were examined for GIR. GIR was present in cells which were rec+ and lon+ and absent in cells which were either rec− or lon−. Host-cell reactivation in these cells and the effects of caffeine, acriflavine, and ultra-violet light exposure on the sensitivity to gamma-rays of cells grown in glucose-enriched nutrient broth are all consistent with the hypothesis that, at low gamma-ray doses, glucose enhances the type of recovery controlled by the rec+ loci.