High-cell-density regulation of the Pseudomonas aeruginosa type III secretion system: implications for tryptophan catabolites

Autor: Madiha Derouazi, Hichem Chaker, Didier Filopon, Stephanie Boullanger, Benoît Polack, Da-Kang Shen, Bertrand Toussaint
Přispěvatelé: TheREx, Techniques de l'Ingénierie Médicale et de la Complexité - Informatique, Mathématiques et Applications, Grenoble - UMR 5525 (TIMC-IMAG), VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Department of Microbiology and Parasitology, Shanghai Jiao Tong University School of Medicine-Shanghai Jiao Tong University School of Medicine, VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Centre de Recherches sur les Macromolécules Végétales (CERMAV), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), S. D. K. was supported by a PhD scholarship from the Agence Universitaire de la Francophonie, Universidad Michoacana de San Nicolas de Hidalgo, Michoacan, Mexico, University of Nottingham, UK, inconnu, Inconnu
Jazyk: angličtina
Rok vydání: 2008
Předmět:
MESH: Indoleacetic Acids
MESH: Protein Transport
MESH: Mutation
[SDV.BIO]Life Sciences [q-bio]/Biotechnology
Virulence Factors
MESH: Kynurenine
Tryptophan synthase
Biology
medicine.disease_cause
Microbiology
Virulence factor
Type three secretion system
03 medical and health sciences
chemistry.chemical_compound
Bacterial Proteins
medicine
Transcriptional regulation
[INFO.INFO-BT]Computer Science [cs]/Biotechnology
MESH: Bacterial Proteins
Kynurenine
ComputingMilieux_MISCELLANEOUS
MESH: Tryptophan
030304 developmental biology
MESH: Virulence Factors
Regulation of gene expression
0303 health sciences
MESH: Gene Expression Regulation
Bacterial
Indoleacetic Acids
030306 microbiology
Pseudomonas aeruginosa
Tryptophan
Gene Expression Regulation
Bacterial
biochemical phenomena
metabolism
and nutrition
bacterial infections and mycoses
3. Good health
Protein Transport
Biochemistry
chemistry
Mutation
MESH: Pseudomonas aeruginosa
biology.protein
bacteria
Zdroj: Microbiology
Microbiology, Microbiology Society, 2008, 154 (8), pp.2195-208. ⟨10.1099/mic.0.2007/013680-0⟩
Microbiology-Sgm
Microbiology-Sgm, 2008, pp.2195-2208
ISSN: 1350-0872
1465-2080
DOI: 10.1099/mic.0.2007/013680-0⟩
Popis: International audience; The Pseudomonas aeruginosa type III secretion system (T3SS) is known to be a very important virulence factor in acute human infections, but it is less important in maintaining chronic infections in which T3SS genes are downregulated. In vitro, the activation of T3SS expression involves a positive activating loop that acts on the transcriptional regulator ExsA. We have observed that in vivo T3SS expression is cell density-dependent in a manner that does not need known quorum-sensing (QS) signals. In addition, stationary-phase culture supernatants added to exponential-phase growing strains can inhibit T3SS expression. The analysis of transposon insertion mutants showed that the production of such T3SS-inhibiting signals might depend on tryptophan synthase and hence tryptophan, which is the precursor of signalling molecules such as indole-3-acetic acid (IAA), kynurenine and Pseudomonas quinolone signal (PQS). Commercially available tryptophan-derived molecules were tested for their role in the regulation of T3SS expression. At millimolar concentrations, IAA, 1-naphthalacetic acid (NAA) and 3-hydroxykynurenine inhibited T3SS expression. Inactivation of the tryptophan dioxygenase-encoding kynA gene resulted in a decrease in the T3SS-inhibiting activity of supernatants. These observations suggest that tryptophan catabolites are involved in the downregulation of T3SS expression in the transition from a low- to a high-cell-density state.
Databáze: OpenAIRE
Externí odkaz: