The lethal interaction of X ray and penicillin induced lesions following X-irradiation of Escherichia coli B/R in the presence of hypoxic cell sensitizers.

When Escherichia coli B/r were x-irradiated under anoxia in the presence of different electron-affinic sensitizers and then incubated in broth containing penicillin (at a concentration that did not kill unirradiated cells) additional killing of the bacteria occurred provided the sensitizers were of relatively high lipophilicity. The overall effect was to increase the efficiency of these sensitizers. It is concluded that sensitizer-dependent latent radiation lesions(s) are produced in membrane components of the cell envelope that interact with damage caused by penicillin in the peptidoglycan layer and this causes the additional lethality.