title: RecA-independent resistance to irradiation with u.v. light in acid-habituated Escherichia coli.
abstract: Growth of Escherichia coli 1829 ColV, I-K94 at pH 5.0 led to an increase in u.v. resistance compared with cells grown at pH 7.0. This was due to a phenotypic change, since organisms grown at pH 7.0 showed increased resistance after only 2.5-5.0 min incubation at the mildly acid pH. Other E. coli K12 derivatives became more u.v.-resistant at pH 5.0 including uvrA, recA and polA1 mutants. Organisms grown at pH 5.0 also showed increased Weigle reactivation of u.v.-irradiated lambda phage and this applied to the repair-deficient mutants as well as the parent strains. Both the increased u.v. resistance of acid-habituated cells and their increased ability to bring about Weigle reactivation appear to involve RecA-independent processes and are presumably, therefore, independent of the SOS response.
authors.affiliation: Department of Biology, University College London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Goodson
authors.forename: R J
authors.initials: RJ
authors.lastname: Rowbury
mesh_terms: D004260:DNA Repair / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects*; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D011938:Rec A Recombinases / Q000235:genetics*; D014466:Ultraviolet Rays
chemical_list: D011938:Rec A Recombinases