title: Radiation sensitivity of Haemophilus influenzae: a composite response.
abstract: The survival of ultraviolet (UV)-irradiated cultures of Haemophilus influenzae Rd is determined by at least two responses: (i) excision-repair ability and (ii) UV-induced cell lysis. An UV-resistant mutant, BC200, has the same capabilities as the wild type, Rd, for excising dimers but does not exhibit lysis. Lytic response is dose-dependent. Relative to the wild type, a lower dose of UV causes lysis of a UV-sensitive mutant, BC100, which is incapable of excising thymine dimers. A lytic protein is present in cultures undergoing lysis. Synthesis of this protein is initiated 45 to 60 min after irradiation. Lysis appears to be due to derepression of a defective prophage which codes for an endolysin-like lytic enzyme.
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis; D001433:Bacteriolysis / Q000187:drug effects; D002701:Chloramphenicol / Q000494:pharmacology; D003470:Culture Media; D004492:Edetic Acid; D005827:Genetics, Microbial; D006193:Haemophilus influenzae / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects*; D008858:Microscopy, Phase-Contrast; D009154:Mutation; D011830:Radiation Effects; D013053:Spectrophotometry; D013941:Thymine; D014466:Ultraviolet Rays
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D002701:Chloramphenicol; D004492:Edetic Acid; D013941:Thymine