title: An oxygen dependent X-ray lesion in Escherichia coli strain B/r detected by penicillin.
abstract: Enhancement of lethal damage to E. coli B/r by penicillin was observed after X-irradiation under aerobic conditions but not after exposure to X-rays under anoxia or after U.V. (260 nm). No enhancement of damage occurred when incubation with penicillin was delayed for 2 hours after aerobic X-irradiation. This enhancing effect was only detected in this strain and not in the filamentous strain E. coli B. It is concluded that an X-ray induced lesion, sensitive to the presence of oxygen at the time of irradiation and probably located in the cell envelope, initiates filamentation in E. coli B/r, which results in lethal damage in this strain.
mesh_terms: D002462:Cell Membrane / Q000187:drug effects / Q000528:radiation effects; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects*; D010100:Oxygen; D010406:Penicillins / Q000494:pharmacology*; D013997:Time Factors; D014466:Ultraviolet Rays; D014965:X-Rays
chemical_list: D010406:Penicillins; D010100:Oxygen