title: Regulation of 2,4,5-trichlorophenoxyacetic acid and chlorophenol metabolism in Pseudomonas cepacia AC1100.
abstract: The expression of the degradative genes encoding 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), 2,4,5-trichlorophenol (2,4,5-TCP), and pentachlorophenol (PCP) dechlorination in a 2,4,5-T-degrading strain of Pseudomonas cepacia was examined during growth on alternate carbon sources. The dechlorination mechanisms for all three compounds were expressed in 2,4,5-T- and 2,4,5-TCP-grown cells but were not expressed in cells grown on succinate, glucose, or lactate. The addition of 2,4,5-TCP or PCP to cells grown on succinate or lactate resulted in the expression of the 2,4,5-TCP dechlorination mechanism in resting cells after 1-h lag. This expression was prevented by the presence of chloramphenicol in the resting cell suspension. Succinate-plus-PCP-grown resting cells preincubated with 2,4,5-TCP fully induced the trichlorophenol dechlorination system and partially induced the PCP dechlorination system. Preincubation of succinate-plus-PCP-grown resting cells with PCP induced neither the 2,4,5-TCP nor the PCP dechlorinating system. Succinate-grown resting cells converted 2,4,5-T to 2,4,5-TCP even in the presence of chloramphenicol. Thus, the data indicate that the enzyme(s) which converts 2,4,5-T to 2,4,5-TCP is constitutively expressed, whereas those that convert 2,4,5-TCP to central intermediates are induced by 2,4,5-TCP but not by 2,4,5-T or PCP and are repressed in the presence of an alternate carbon source.
mesh_terms: D015085:2,4,5-Trichlorophenoxyacetic Acid / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis; D001673:Biodegradation, Environmental; D002733:Chlorophenols / Q000378:metabolism*; D004790:Enzyme Induction; D005947:Glucose / Q000378:metabolism; D007700:Kinetics; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D010416:Pentachlorophenol / Q000378:metabolism*; D011549:Pseudomonas / Q000201:enzymology* / Q000254:growth & development; D013386:Succinates / Q000378:metabolism; D019802:Succinic Acid
chemical_list: D001426:Bacterial Proteins; D002733:Chlorophenols; D007773:Lactates; D013386:Succinates; C009534:2,4,5-trichlorophenol; D019344:Lactic Acid; D015085:2,4,5-Trichlorophenoxyacetic Acid; D019802:Succinic Acid; D010416:Pentachlorophenol; D005947:Glucose