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Responses of Pseudomonas putida to toxic aromatic carbon sources.
- Source :
-
Journal of biotechnology [J Biotechnol] 2012 Jul 31; Vol. 160 (1-2), pp. 25-32. Date of Electronic Publication: 2012 Feb 01. - Publication Year :
- 2012
-
Abstract
- A number of bacteria can use toxic compounds as carbon sources and have developed complex regulatory networks to protect themselves from the toxic effects of these compounds as well as to benefit from their nutritious properties. As a model system we have studied the responses of Pseudomonas putida strains to toluene. Although this compound is highly toxic, several strains are able to use it for growth. Particular emphasis was given to the responses in the context of taxis, resistance and toluene catabolism. P. putida strains analysed showed chemotactic movements towards toluene. Strain DOT-T1E was characterised by an extreme form of chemotaxis, termed hyperchemotaxis, which is mediated by the McpT chemoreceptor encoded by plasmid pGRT1. Close McpT homologs are found in a number of other plasmids encoding degradation pathways of toxic compounds. The pGRT1 plasmid harbours also the genes for the TtgGHI efflux pump which was identified as the primary determinant for the resistance of strain DOT-T1E towards toluene. Pump expression is controlled by the TtgV repressor in response to a wide range of different mono- and biaromatic compounds. Strain DOT-T1E is able to degrade toluene, benzene and ethylbenzene via the toluene dioxygenase (TOD) pathway. The expression of the pathway operon is controlled by the TodS/T two component system. The sensor kinase TodS recognizes toluene with nanomolar affinity, which in turn triggers an increase in its autophosphorylation and consequently transcriptional activation. Data suggest that transcriptional activation of the TOD pathway occurs at very low toluene concentrations whereas TtgV mediated induction of pump expression sets in as the toluene concentration further increases.<br /> (Copyright © 2012 Elsevier B.V. All rights reserved.)
- Subjects :
- Chemotaxis physiology
Gene Expression Regulation, Bacterial
Membrane Transport Proteins genetics
Membrane Transport Proteins metabolism
Oxygenases genetics
Oxygenases metabolism
Phosphorylation
Plasmids
Pseudomonas putida genetics
Signal Transduction
Pseudomonas putida drug effects
Pseudomonas putida metabolism
Toluene metabolism
Toluene toxicity
Subjects
Details
- Language :
- English
- ISSN :
- 1873-4863
- Volume :
- 160
- Issue :
- 1-2
- Database :
- MEDLINE
- Journal :
- Journal of biotechnology
- Publication Type :
- Academic Journal
- Accession number :
- 22321573
- Full Text :
- https://doi.org/10.1016/j.jbiotec.2012.01.026