title: Swarming of Pseudomonas aeruginosa is dependent on cell-to-cell signaling and requires flagella and pili.
abstract: We describe swarming in Pseudomonas aeruginosa as a third mode of surface translocation in addition to the previously described swimming and twitching motilities. Swarming in P. aeruginosa is induced on semisolid surfaces (0.5 to 0.7% agar) under conditions of nitrogen limitation and in response to certain amino acids. Glutamate, aspartate, histidine, or proline, when provided as the sole source of nitrogen, induced swarming, while arginine, asparagine, and glutamine, among other amino acids, did not sustain swarming. Cells from the edge of the swarm were about twice as long as cells from the swarm center. In both instances, bacteria possessing two polar flagella were observed by light and electron microscopy. While a fliC mutant of P. aeruginosa displayed slightly diminished swarming, a pilR and a pilA mutant, both deficient in type IV pili, were unable to swarm. Furthermore, cells with mutations in the las cell-to-cell signaling system showed diminished swarming behavior, while rhl mutants were completely unable to swarm. Evidence is presented for rhamnolipids being the actual surfactant involved in swarming motility, which explains the involvement of the cell-to-cell signaling circuitry of P. aeruginosa in this type of surface motility.
authors.affiliation: Department of Genetics and Microbiology, University Medical Center, Sciences III, University of Geneva, CH-1211 Geneva 4, Switzerland. Thilo.Kohler@medecine.unige.ch
authors.forename: T
authors.initials: T
authors.lastname: Köhler
authors.forename: L K
authors.initials: LK
authors.lastname: Curty
authors.forename: F
authors.initials: F
authors.lastname: Barja
authors.forename: C
authors.initials: C
authors.lastname: van Delden
authors.forename: J C
authors.initials: JC
authors.lastname: Pechère
mesh_terms: D001224:Aspartic Acid; D001426:Bacterial Proteins / Q000235:genetics; D003470:Culture Media; D004268:DNA-Binding Proteins / Q000235:genetics; D003651:Decanoates / Q000378:metabolism; D004187:Disaccharides / Q000378:metabolism; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000502:physiology*; D005407:Flagella / Q000502:physiology* / Q000648:ultrastructure; D005408:Flagellin / Q000235:genetics; D018698:Glutamic Acid; D006639:Histidine; D008854:Microscopy, Electron; D009068:Movement; D009154:Mutation; D009584:Nitrogen; D011392:Proline; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000502:physiology*; D012210:Rhamnose / Q000031:analogs & derivatives / Q000378:metabolism; D015398:Signal Transduction; D013501:Surface-Active Agents / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D004268:DNA-Binding Proteins; D003651:Decanoates; D004187:Disaccharides; C081237:LasI protein, Pseudomonas aeruginosa; C080365:LasR protein, Pseudomonas aeruginosa; D013501:Surface-Active Agents; D015534:Trans-Activators; D014157:Transcription Factors; D005408:Flagellin; C074774:pilR protein, Pseudomonas aeruginosa; D036781:Fimbriae Proteins; D001224:Aspartic Acid; C085734:rhamnopyranosyl-3-hydroxydecanoyl-3-hydroxydecanoate; D018698:Glutamic Acid; C085735:2-O-rhamnopyranosyl-rhamnopyranosyl-3-hydroxyldecanoyl-3-hydroxydecanoate; D006639:Histidine; D011392:Proline; D009584:Nitrogen; D012210:Rhamnose