Synergistic killing of Escherichia coli K-12 by UV (254 nm) and H2O2.
Prior UV irradiation strongly increased the sensitivity to H2O2 of wild-type E. coli K-12 cells. This synergistic lethal interaction was also observed to a reduced extent in a polA mutant but was absent in uvrA, uvrArecA and xthA mutants. In a recA mutant an antagonist effect was observed. Prior H2O2 treatment did not sensitize the wild-type cells to UV irradiation. Alkaline and neutral sucrose gradient analysis, as well as DNA degradation studies, demonstrated that the synergism is due to the production of DNA double-strand breaks and a block of their repair. The possible mechanism of induction of such lesions is discussed.
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Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brasil.
Carvalho
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D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004269:DNA, Bacterial / Q000187:drug effects / Q000528:radiation effects; D004926:Escherichia coli / Q000187:drug effects / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D014466:Ultraviolet Rays
D004269:DNA, Bacterial; D006861:Hydrogen Peroxide