INJURY OF ESCHERICHIA-COLI IN PHYSIOLOGICAL PHOSPHATE-BUFFERED SALINEINDUCED BY FAR-INFRARED IRRADIATION

Injury in Escherichia coli irradiated by far-infrared radiation (FIR) was examined. We used penicillin G (PCG), chloramphenicol (CP), rifamp icin (REP) and nalidixic acid (NA) as selective reagents, and tried to evaluate the injury in bacteria irradiated by FIR on the basis of the changes in the sensitivity to selective reagents. The validity of thi s method was examined using UV pasteurization. E. coli irradiated by U V became more sensitive to CP and NA, which indicated that UV irradiat ion damaged nucleic acid in E. coli. This result agrees with those dem onstrated by many researchers and suggests this method is applicable t o useful evaluation of the damaged part in bacteria induced by stresse s. E. coli irradiated by FIR became more sensitive to RFP and CP, whic h suggests that FIR irradiation damages RNA polymerase and ribosome in E. coli. Though similar changes in the sensitivity were obtained in t he case of thermal conductive heating, the pasteurization effect of RR irradiation was much greater than that of conductive heating.