title: Expression of dibenzothiophene-degradative genes in two Pseudomonas species.
abstract: The genes encoding dibenzothiophene (DBT) degradation in Pseudomonas alcaligenes strain DBT2 were cloned into plasmid pC1 by other workers. This plasmid was conjugally transferred into a spontaneous variant of Pseudomonas sp. HL7b (designated HL7bR) incapable of oxidizing DBT (Dbt- phenotype). Acquisition of plasmid pC1 simultaneously restored oxidation of DBT and naphthalene to the transconjugant, although the primary DBT metabolite produced by transconjugant HL7bR(pC1) corresponded to that produced by wild-type strain DBT2 rather than that from wild-type strain HL7b. Inducers of the naphthalene pathway (naphthalene, salicylic acid, and 2-aminobenzoate) stimulated DBT oxidation in transconjugant HL7bR(pC1) when present at 0.1 mM concentrations but had no effect on wild-type strain HL7b. Higher concentrations (5 mM) of salicylic acid and naphthalene were inhibitory to DBT oxidation in all strains. DNA-DNA hybridization was not observed between plasmid pC1 and genomic DNA from strains HL7b or HL7bR, nor between authentic naphthalene-degradative genes (plasmid NAH2) and either plasmid pC1 or strain HL7b, despite the observation that the degradative genes encoded on plasmid pC1 functionally resembled broad-specificity naphthalene-degradative genes. Transconjugant HL7bR(pC1) is a mosaic of the parental types regarding DBT metabolite production, regulation, and use of carbon sources.
authors: Department of Microbiology, University of Alberta, Edmonton, Canada.
authors: J M
authors: JM
authors: Foght
authors: D W
authors: DW
authors: Westlake
mesh_terms: D001673:Biodegradation, Environmental; D003001:Cloning, Molecular; D003227:Conjugation, Genetic; D015964:Gene Expression Regulation, Bacterial; D009693:Nucleic Acid Hybridization; D010084:Oxidation-Reduction; D010957:Plasmids; D011549:Pseudomonas / Q000235:genetics* / Q000378:metabolism; D013876:Thiophenes / Q000378:metabolism*
chemical_list: D013876:Thiophenes; C016366:dibenzothiophene