title: Effects of x irradiation on a temperate bacteriophage of Haemophilus influenzae.
abstract: The inactivation of bacteriophage HP1c1 by X rays in a complex medium was found to be exponential, with a D0 (the X-ray exposure necessary to reduce the survival of the phage to 37%) of approximately 90 kR. Analysis of results of sucrose sedimentation of DNA from X-irradiated whole phage showed that the D0 for intactness of single strands was about 105kR, and for intactness of double strands, it was much higher. The D0 for attachment of X-irradiated phage to the host was roughly estimated as about 1,100 kR. Loss of DNA from the phage occurred and was probably due to lysis of the phage by X irradiation, but the significance of the damage is not clear. The production of single-strand breaks approaches the rate of survival loss after X irradiation. However, single-strand breaks produced by UV irradiation, in the presence of H2O2, equivalent to 215 kR of X rays, showed no lethal effect on the phage. Although UV-sensitive mutants of the host cell, Haemophilus influenzae, have been shown to reactivate UV-irradiated phage less than does the wild-type host cell, X-irradiated phage survive equally well on the mutants as on the wild type, a fact suggesting that other repair systems are involved in X-ray repair.
mesh_terms: D001435:Bacteriophages / Q000378:metabolism / Q000528:radiation effects*; D004260:DNA Repair; D004279:DNA, Viral / Q000096:biosynthesis / Q000528:radiation effects; D006193:Haemophilus influenzae / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009154:Mutation; D014466:Ultraviolet Rays; D014965:X-Rays
chemical_list: D004279:DNA, Viral; D006861:Hydrogen Peroxide