title: Biofilm formation and antibiotic production in Ruegeria mobilis are influenced by intracellular concentrations of cyclic dimeric guanosinmonophosphate.
abstract: In many species of the marine Roseobacter clade, periods of attached life, in association with phytoplankton or particles, are interspersed with planktonic phases. The purpose of this study was to determine whether shifts between motile and sessile life in the globally abundant Roseobacter clade species Ruegeria mobilis are associated with intracellular concentrations of the signal compound cyclic dimeric guanosinmonophosphate (c-di-GMP), which in bacteria regulates transitions between motile and sessile life stages. Genes for diguanylate cyclases and phosphodiesterases, which are involved in c-di-GMP signalling, were found in the genome of R. mobilis strain F1926. Ion pair chromatography-tandem mass spectrometry revealed 20-fold higher c-di-GMP concentrations per cell in biofilm-containing cultures than in planktonic cells. An introduced diguanylate cyclase gene increased c-di-GMP and enhanced biofilm formation and production of the potent antibiotic tropodithietic acid (TDA). An introduced phosphodiesterase gene decreased c-di-GMP and reduced biofilm formation and TDA production. tdaC, a key gene for TDA biosynthesis, was expressed only in attached or biofilm-forming cells, and expression was induced immediately after initial attachment. In conclusion, c-di-GMP signalling controls biofilm formation and biofilm-associated traits in R. mobilis and, as suggested by presence of GGDEF and EAL domain protein genes, also in other Roseobacter clade species.
authors.affiliation: Department of Systems Biology, Technical University of Denmark, Søltofts Plads, Bldg. 221, DK-2800, Kgs. Lyngby, Denmark.
authors.forename: Paul W
authors.initials: PW
authors.lastname: D'Alvise
authors.forename: Olivera
authors.initials: O
authors.lastname: Magdenoska
authors.forename: Jette
authors.initials: J
authors.lastname: Melchiorsen
authors.forename: Kristian F
authors.initials: KF
authors.lastname: Nielsen
authors.forename: Lone
authors.initials: L
authors.lastname: Gram
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics; D018441:Biofilms / Q000254:growth & development*; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D010727:Phosphoric Diester Hydrolases / Q000235:genetics; D019761:Phosphorus-Oxygen Lyases / Q000235:genetics; D017434:Protein Structure, Tertiary; D041902:Rhodobacteraceae / Q000378:metabolism / Q000502:physiology*; D014334:Tropolone / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C527336:tropodithietic acid; C062025:bis(3',5')-cyclic diguanylic acid; D014334:Tropolone; D010727:Phosphoric Diester Hydrolases; D019761:Phosphorus-Oxygen Lyases; C060720:diguanylate cyclase; D006152:Cyclic GMP