title: Biofilm formation by Pseudomonas aeruginosa wild type, flagella and type IV pili mutants.
abstract: Biofilm formation by Gfp-tagged Pseudomonas aeruginosa PAO1 wild type, flagella and type IV pili mutants in flow chambers irrigated with citrate minimal medium was characterized by the use of confocal laser scanning microscopy and comstat image analysis. Flagella and type IV pili were not necessary for P. aeruginosa initial attachment or biofilm formation, but the cell appendages had roles in biofilm development, as wild type, flagella and type IV pili mutants formed biofilms with different structures. Dynamics and selection during biofilm formation were investigated by tagging the wild type and flagella/type IV mutants with Yfp and Cfp and performing time-lapse confocal laser scanning microscopy in mixed colour biofilms. The initial microcolony formation occurred by clonal growth, after which wild-type P. aeruginosa bacteria spread over the substratum by means of twitching motility. The wild-type biofilms were dynamic compositions with extensive motility, competition and selection occurring during development. Bacterial migration prevented the formation of larger microcolonial structures in the wild-type biofilms. The results are discussed in relation to the current model for P. aeruginosa biofilm development.
authors.affiliation: Molecular Microbial Ecology Group, BioCentrum-DTU, Building 301, Technical University of Denmark, DK-2800 Lyngby, Denmark.
authors.forename: Mikkel
authors.initials: M
authors.lastname: Klausen
authors.forename: Arne
authors.initials: A
authors.lastname: Heydorn
authors.forename: Paula
authors.initials: P
authors.lastname: Ragas
authors.forename: Lotte
authors.initials: L
authors.lastname: Lambertsen
authors.forename: Anders
authors.initials: A
authors.lastname: Aaes-Jørgensen
authors.forename: Søren
authors.initials: S
authors.lastname: Molin
authors.forename: Tim
authors.initials: T
authors.lastname: Tolker-Nielsen
mesh_terms: D018441:Biofilms / Q000254:growth & development*; D002951:Citrates / Q000378:metabolism; D003470:Culture Media; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000378:metabolism*; D005407:Flagella / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D007091:Image Processing, Computer-Assisted; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D009154:Mutation; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012984:Software
chemical_list: D002951:Citrates; D003470:Culture Media; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins