title: Transposon-induced catalase-deficient Agrobacterium tumefaciens.
abstract: Agrobacterium tumefaciens MKR, a nonpathogenic strain, has three catalase isozymes and one superoxide dismutase but no detectable peroxidase activity. A large number (8400) of transconjugants were obtained with pSUP1011::Tn5 suicide vector. The transposition frequencies were found to be greater in biparental mating than in triparental mating with helper plasmid. Mutants MLA31, MLA32, MLA41, and MLA41(a), generated by transposon mutagenesis, all lacked one of the catalase isozymes. Mutants were more susceptible to cell death than the wild type upon direct exposure to 10.0 mmol L-1 H2O2. The specific activity of the enzyme catalase was found to be higher in nitrogen-rich growth medium than carbon-rich growth medium.
authors.affiliation: Biology Programme, Faculty of Natural Resources and Environmental Studies, The University of Northern British Columbia, 3333 University Way, Prince George, V2N 4Z9, British Columbia, Canada.
authors.forename: M B
authors.initials: MB
authors.lastname: Khetmalas
mesh_terms: D020642:Acatalasia; D016960:Agrobacterium tumefaciens / Q000201:enzymology* / Q000235:genetics; D004251:DNA Transposable Elements; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D004251:DNA Transposable Elements; D013482:Superoxide Dismutase