title: Isolation and transposon mutagenesis of a Pseudomonas putida KT2442 toluene-resistant variant: involvement of an efflux system in solvent resistance.
abstract: A toluene-resistant variant of Pseudomonas putida KT2442, strain TOL, was isolated after liquid cultivation under xylene followed by toluene for 1 month in each condition. Almost all the populations of the variant strain formed small but readily visible colonies under toluene within 24 h at 30 degrees C. The toluene-resistant strain also showed an increase in resistance to some unrelated antibiotics. Several toluene-sensitive Tn5 mutants have been isolated from the toluene-resistant strain and showed various levels of sensitivity. Most of these mutations did not cause significant changes in antibiotic resistance; however, one of the mutants (TOL-4) was highly susceptible to both organic solvents and various antibiotics, especially beta-lactams. Sequencing analysis revealed that the mutation in TOL-4 had been introduced into a gene that may encode a transporter protein of an efflux system. This efflux system is very similar to one of the multidrug efflux systems of Pseudomonas aeruginosa. These observations indicate that a multidrug efflux system plays a major role in the organic solvent resistance of P. putida TOL. However, several other genes may also be involved.
authors.affiliation: DEEPSTAR Group, Japan Marine Science and Technology Center, Yokosuka. fukumori@jamstec.go.jp
authors.forename: F
authors.initials: F
authors.lastname: Fukumori
authors.forename: H
authors.initials: H
authors.lastname: Hirayama
authors.forename: H
authors.initials: H
authors.lastname: Takami
authors.forename: A
authors.initials: A
authors.lastname: Inoue
authors.forename: K
authors.initials: K
authors.lastname: Horikoshi
mesh_terms: D000222:Adaptation, Physiological; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001483:Base Sequence; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004352:Drug Resistance, Microbial; D014644:Genetic Variation; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016958:Pseudomonas putida / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D012997:Solvents; D014050:Toluene / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D012997:Solvents; D014050:Toluene