title: Alginate acetylation influences initial surface colonization by mucoid Pseudomonas aeruginosa.
abstract: Mucoid strains of Pseudomonas aeruginosa overproduce the exopolysaccharide alginate, which is substituted with O-acetyl groups. Under non-growing conditions in phosphate buffer, a mucoid clinical strain formed microcolonies on steel surfaces, while an acetylation-defective mutant was unable to form cell clusters. Enzymatic degradation of alginate by alginate lyase prevented microcolony formation of the mucoid parent strain. In a continuous-culture flow-cell system, using gluconate minimal medium, the mucoid strain with acetylated alginate formed microcolonies and grew into heterogenous biofilms, whereas the acetylation-defective mutant produced a thinner and more homogeneous biofilm. A lowered viscosity of extracellular material from the acetylation-defective mutant indicated a weakening of exopolymer interactions by loss of acetyl groups. These results suggest that acetyl substituents are necessary for the function of high-molecular-mass alginate to mediate cell aggregation into microcolonies in the early stages of biofilm development by mucoid P. aeruginosa, thereby determining the architecture of the mature biofilm.
authors.affiliation: Department of Aquatic Microbiology, Biofilm Centre, University of Duisburg-Essen, Geibelstrasse 41, 47057 Duisburg, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Tielen
authors.forename: Martin
authors.initials: M
authors.lastname: Strathmann
authors.forename: Karl-Erich
authors.initials: KE
authors.lastname: Jaeger
authors.forename: Hans-Curt
authors.initials: HC
authors.lastname: Flemming
authors.forename: Jost
authors.initials: J
authors.lastname: Wingender
mesh_terms: D000107:Acetylation; D000464:Alginates / Q000378:metabolism*; D001422:Bacterial Adhesion / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D003470:Culture Media; D020723:Glucuronic Acid / Q000378:metabolism*; D006603:Hexuronic Acids / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D011133:Polysaccharide-Lyases / Q000235:genetics / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000201:enzymology / Q000235:genetics / Q000254:growth & development* / Q000502:physiology
chemical_list: D000464:Alginates; D003470:Culture Media; D006603:Hexuronic Acids; D011135:Polysaccharides, Bacterial; D020723:Glucuronic Acid; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase