Developmental pathway for biofilm formation in curli-producing Escherichia coli strains: role of flagella, curli and colanic acid.
This work was performed to establish a model describing bacterial surface structures involved in biofilm development, in curli-overproducing Escherichia coli K-12 strains, at 30 degrees C, and in minimal growth medium. Using a genetic approach, in association with observations of sessile communities by light and electron microscopic techniques, the role of protein surface structures, such as flagella and curli, and saccharidic surface components, such as the E. coli exopolysaccharide, colanic acid, was determined. We show that, in the context of adherent ompR234 strains, (i) flagellar motility is not required for initial adhesion and biofilm development; (ii) both primary adhesion to inert surfaces and development of multilayered cell clusters require curli synthesis; (iii) curli display direct interactions with the substratum and form interbacterial bundles, allowing a cohesive and stable association of cells; and (iv) colanic acid does not appear critical for bacterial adhesion and further biofilm development but contributes to the biofilm architecture and allows for the formation of voluminous biofilms.
Laboratoire de Microbiologie et Génétique, CNRS UMR 5577, Institut National des Sciences Appliquées de Lyon, Villeurbanne, France. cprigent@insa-lyon.fr
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D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D018441:Biofilms / Q000254:growth & development*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D029968:Escherichia coli Proteins; D005407:Flagella / Q000235:genetics / Q000502:physiology*; D008855:Microscopy, Electron, Scanning; D010969:Plastics; D011134:Polysaccharides / Q000235:genetics / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000378:metabolism; D011137:Polystyrenes
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D010969:Plastics; D011134:Polysaccharides; D011135:Polysaccharides, Bacterial; D011137:Polystyrenes; C489688:csgA protein, E coli; C077481:Crl protein, Bacteria; C004275:colanic acid