title: Osmotic stress and phosphate limitation alter production of cell-to-cell signal molecules and rhamnolipid biosurfactant by Pseudomonas aeruginosa.
abstract: In Pseudomonas aeruginosa, rhamnolipid production is controlled by the quorum-sensing system RhlRI, which itself depends on LasRI. These systems use cell-to-cell signal molecules: N-butyryl-l-homoserine lactone (C4-HSL) and N-(3-oxododecanoyl)-l-homoserine lactone (3OC(12)-HSL), respectively. Whereas both HSLs were produced in M63 medium, rhamnolipid synthesis was not achieved. Phosphate limitation reduced the HSL concentrations, while allowing rhamnolipid production. Hyperosmotic shock applied during the exponential growth phase stopped the accumulation of 3OC(12)-HSL, and prevented C4-HSL and rhamnolipid production. These defects result from lower expression of genes involved in C4-HSL and rhamnolipid syntheses. The osmoprotectant glycine betaine partially restored C4-HSL and rhamnolipid production.
authors.affiliation: Laboratoire de Biotechnologie et Chimie Marines, EA 3884, Université de Bretagne Sud, BP 92116, 56321 Lorient, France.
authors.forename: Alexis
authors.initials: A
authors.lastname: Bazire
authors.forename: Alexandra
authors.initials: A
authors.lastname: Dheilly
authors.forename: Farès
authors.initials: F
authors.lastname: Diab
authors.forename: Danièle
authors.initials: D
authors.lastname: Morin
authors.forename: Mohamed
authors.initials: M
authors.lastname: Jebbar
authors.forename: Dominique
authors.initials: D
authors.lastname: Haras
authors.forename: Alain
authors.initials: A
authors.lastname: Dufour
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000096:biosynthesis; D001483:Base Sequence; D001622:Betaine / Q000494:pharmacology; D004269:DNA, Bacterial / Q000235:genetics; D006017:Glycolipids / Q000096:biosynthesis*; D006801:Humans; D007700:Kinetics; D009997:Osmotic Pressure; D010710:Phosphates / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D015398:Signal Transduction; D013501:Surface-Active Agents / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D006017:Glycolipids; D010710:Phosphates; D013501:Surface-Active Agents; C418382:rhamnolipid; C088386:homoserine lactone; D001622:Betaine; D015107:4-Butyrolactone