Genetic evidence that the Vibrio cholerae monolayer is a distinct stage in biofilm development.
Biofilm development is conceived as a developmental process in which free swimming cells attach to a surface, first transiently and then permanently, as a single layer. This monolayer of immobilized cells gives rise to larger cell clusters that eventually develop into the biofilm, a three-dimensional structure consisting of large pillars of bacteria interspersed with water channels. Previous studies have shown that efficient development of the Vibrio cholerae biofilm requires a combination of pili, flagella and exopolysaccharide. Little is known, however, regarding the requirements for monolayer formation by wild-type V. cholerae. In this work, we have isolated the wild-type V. cholerae monolayer and demonstrated that the environmental signals, bacterial structures, and transcription profiles that induce and stabilize the monolayer state are unique. Cells in a monolayer are specialized to maintain their attachment to a surface. The surface itself activates mannose-sensitive haemagglutinin type IV pilus (MSHA)-mediated attachment, which is accompanied by repression of flagellar gene transcription. In contrast, cells in a biofilm are specialized to maintain intercellular contacts. Progression to this stage occurs when exopolysaccharide synthesis is induced by environmental monosaccharides. We propose a model for biofilm development in natural environments in which cells form a stable monolayer on a surface. As biotic surfaces are degraded with subsequent release of carbohydrates, the monolayer develops into a biofilm.
Moorthy
Sudha
S
Division of Geographic Medicine and Infectious Diseases, New England Medical Center, Boston, MA 02111, USA.
Watnick
Paula I
PI
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D003470:Culture Media; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism; D005407:Flagella / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D006388:Hemagglutinins / Q000235:genetics / Q000378:metabolism; D008358:Mannose / Q000378:metabolism; D037601:Mannose-Binding Lectin; D008766:Methylmannosides / Q000378:metabolism / Q000494:pharmacology; D009068:Movement; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D012329:RNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic; D014734:Vibrio cholerae / Q000235:genetics* / Q000254:growth & development*
D001426:Bacterial Proteins; D003470:Culture Media; D006388:Hemagglutinins; D037601:Mannose-Binding Lectin; D008766:Methylmannosides; C101032:MshA protein, Vibrio cholerae; D011135:Polysaccharides, Bacterial; D012329:RNA, Bacterial; D036781:Fimbriae Proteins; C008466:methylmannoside; D008358:Mannose