Alginate acetylation influences initial surface colonization by mucoid Pseudomonas aeruginosa.
Mucoid strains of Pseudomonas aeruginosa overproduce the exopolysaccharide alginate, which is substituted with O-acetyl groups. Under nongrowing conditions in phosphate buffer, a mucoid clin. strain formed microcolonies on steel surfaces, while an acetylation-defective mutant was unable to form cell clusters. Enzymic degrdn. 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 heterogeneous 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-mol.-mass alginate to mediate cell aggregation into microcolonies in the early stages of biofilm development by mucoid P. aeruginosa, thereby detg. the architecture of the mature biofilm.
Dieser Eintrag ist freigegeben.