title: Effect of repair deficiency and R plasmids on spontaneous and radiation-induced mutability in Pseudomonas aeruginosa.
abstract: The effect of R plasmids on spontaneous and radiation (ultraviolet and gamma)-induced mutability in Pseudomonas aeruginosa was studied in strains containing the radiation-sensitive markers polA3 or rec-2 and the revertable auxotrophic markers hisO27 and trpB1. In the absence of an R plasmid, the radiation-induced mutability was dependent on the recA+ genotype and independent of the polA+ genotype, whereas spontaneous mutability was similar in all genetic backgrounds. R plasmids pPL1, R2, and pMG15 increased the ultraviolet radiation survival and ultraviolet-induced mutability of wild-type and polA host cells but did not alter either effect in a recA mutant. These R plasmids also increased the gamma radiation survival and gamma-induced mutability of wild-type host cells bud pMG15 also enhanced the level of spontaneous mutagenesis in wild-type host cells but not in a polA or recA mutant. These data suggested that a common plasmid gene product(s) may participate in various recA-dependent, error-prone deoxyribonucleic acid repair pathways of P. aeruginosa. The properties of a mutant R plasmid, pPL2, originally selected because it lacked enhanced ultraviolet-induced mutability, supported this conclusion.
mesh_terms: D000483:Alleles; D004260:DNA Repair; D004307:Dose-Response Relationship, Radiation; D005838:Genotype; D009154:Mutation / Q000528:radiation effects*; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D011815:R Factors; D014466:Ultraviolet Rays