title: Pseudomonas putida KT2440 responds specifically to chlorophenoxy herbicides and their initial metabolites.
abstract: Pseudomonas putida KT2440 is often used as a model to investigate toxicity mechanisms and adaptation to hazardous chemicals in bacteria. The objective of this paper was to test the impact of the chlorophenoxy herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-(2,4-dichlorophenoxy)propanoic acid (DCPP) and their metabolites 2,4-dichlorophenol (DCP) and 3,5-dichlorocatechol (DCC), on protein expression patterns and physiological parameters. Both approaches showed that DCC has a different mode of action and induces different responses than DCPP, 2,4-D and DCP. DCC was the most toxic compound and was active as an uncoupler of oxidative phosphorylation. It repressed the synthesis of ferric uptake regulator (Fur)-dependent proteins, e.g. fumarase C and L-ornithine N5-oxygenase, which are involved in oxidative stress response and iron uptake. DCPP, 2,4-D and DCP were less toxic than DCC. They disturbed oxidative phosphorylation to a lesser extent by a yet unknown mechanism. Furthermore, they repressed enzymes of energy-consuming biosynthetic pathways and induced membrane transporters for organic substrates. A TolC homologue component of multidrug resistance transporters was found to be induced, which is probably involved in the removal of lipophilic compounds from membranes.
authors.affiliation: Department of Environmental Microbiology, UFZ - Centre for Environmental Research Leipzig-Halle, Leipzig, Germany. dirk.benndorf@ufz.de
authors.forename: Dirk
authors.initials: D
authors.lastname: Benndorf
authors.forename: Markus
authors.initials: M
authors.lastname: Thiersch
authors.forename: Norbert
authors.initials: N
authors.lastname: Loffhagen
authors.forename: Christfried
authors.initials: C
authors.lastname: Kunath
authors.forename: Hauke
authors.initials: H
authors.lastname: Harms
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000031:analogs & derivatives / Q000633:toxicity; D019297:2,4-Dinitrophenol / Q000633:toxicity; D001426:Bacterial Proteins / Q000378:metabolism*; D002396:Catechols / Q000633:toxicity; D015180:Electrophoresis, Gel, Two-Dimensional; D005649:Fumarate Hydratase / Q000378:metabolism; D006540:Herbicides / Q000633:toxicity*; D006899:Mixed Function Oxygenases / Q000378:metabolism; D010084:Oxidation-Reduction; D010766:Phosphorylation; D020543:Proteome / Q000378:metabolism*; D016958:Pseudomonas putida / Q000187:drug effects* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002396:Catechols; D006540:Herbicides; D020543:Proteome; C063909:3,5-dichlorocatechol; D015084:2,4-Dichlorophenoxyacetic Acid; D006899:Mixed Function Oxygenases; C059419:ornithine N5-oxygenase; C095842:fumarase C; D005649:Fumarate Hydratase; C010571:dichlorprop; D019297:2,4-Dinitrophenol