Osmotic stress and phosphate limitation alter production of cell-to-cell signal molecules and rhamnolipid biosurfactant by Pseudomonas aeruginosa.
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.
Bazire
Alexis
A
Laboratoire de Biotechnologie et Chimie Marines, EA 3884, Université de Bretagne Sud, BP 92116, 56321 Lorient, France.
Dheilly
Alexandra
A
Diab
Farès
F
Morin
Danièle
D
Jebbar
Mohamed
M
Haras
Dominique
D
Dufour
Alain
A
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
D004269:DNA, Bacterial; D006017:Glycolipids; D010710:Phosphates; D013501:Surface-Active Agents; C418382:rhamnolipid; C088386:homoserine lactone; D001622:Betaine; D015107:4-Butyrolactone