title: Proteomic and microscopic analysis of biofilms formed by Listeria monocytogenes 568.
abstract: Biofilm formation may be important in the colonization of the food-processing environment by the food-borne pathogen Listeria monocytogenes. Listeria monocytogenes 568 formed adherent multicellular layers on a variety of test surfaces following growth at 37 degrees C with multiple transfers of the test surface into fresh medium. Microscopic examination of these adherent layers suggest that the cells were surrounded by extracellular material. The presence of a carbohydrate containing extracellular polymeric matrix was confirmed by labelling hydrated adherent layers with fluorescein-conjugated concanavalin A, indicating that these adherent layers are biofilms. To gain insight into the physiological state of cells in these biofilms, the proteomes from biofilm- and planktonic-grown cells from the same cultures were compared using 2-dimensional polyacrylamide gel electrophoresis. Nineteen proteins, which exhibited higher levels of expression in biofilm-grown cells, were successfully identified from the 2-D gels using a combination of MALDI-TOF and MS/MS. Proteins that were found to be more highly expressed in biofilm-grown cells were involved in stress response, envelope and protein synthesis, biosynthesis, energy generation, and regulatory functions. In biofilm-grown cells, many proteins in the pH range 4-6 ran as multiple spots arranged horizontally across the 2-D gels.
authors.affiliation: Centre for Biologics Research, Biologics and Genetic Therapies Directorate, Health Canada, Ottawa, ON.
authors.forename: M A
authors.initials: MA
authors.lastname: Hefford
authors.forename: S
authors.initials: S
authors.lastname: D'Aoust
authors.forename: T D
authors.initials: TD
authors.lastname: Cyr
authors.forename: J W
authors.initials: JW
authors.lastname: Austin
authors.forename: G
authors.initials: G
authors.lastname: Sanders
authors.forename: E
authors.initials: E
authors.lastname: Kheradpir
authors.forename: M L
authors.initials: ML
authors.lastname: Kalmokoff
mesh_terms: D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D003470:Culture Media; D015180:Electrophoresis, Gel, Two-Dimensional; D015964:Gene Expression Regulation, Bacterial; D008089:Listeria monocytogenes / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure*; D013058:Mass Spectrometry; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D020543:Proteome; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D020543:Proteome