Dynamic remodeling of microbial biofilms by functionally distinct exopolysaccharides.
Bottom Line: Conversely, Pel reduced effective cross-linking within the matrix.The wild-type biofilm decreased in effective cross-linking over time, which would be advantageous for the spreading and colonization of new surfaces.The exopolysaccharides were also found to have profound effects on the spatial organization and integration of P. aeruginosa in a mixed-species biofilm model of P. aeruginosa-Staphylococcus aureus.
Affiliation: BioSystems and Micromechanics IRG, Singapore-MIT Alliance for Research and Technology, National University of Singapore, Singapore.Show MeSH
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Mentions: Elastic materials reversibly deform under shear, whereas viscous materials irreversibly deform under shear. To test the hypothesis that Psl makes biofilms more elastic and thus resistant to deformation shear forces, whereas Pel makes the biofilm more malleable, a biofilm streamer cultivation system, which involved growing biofilms on a steel mesh, was developed to assess the correlation between the various P. aeruginosa EPS mutants and biofilm streamer morphology. During the cultivation of P. aeruginosa EPS mutant biofilms, Alg+ Pel+ Psl+ cells initially formed rough surface-attached biofilms. In the later stages, the biofilms became smooth with enhanced spreading (Fig. 6A). Alg+ Pel− Psl+ cells formed rough surface-attached biofilms that developed tall microcolonies with minimal spreading (Fig. 6B). Alg+ Pel+ Psl− cells formed smooth biofilms with extensive streamer formation. In the later stages, the steel mesh was completely covered by the biofilms (Fig. 6C). Alg+ Pel− Psl− cells attached to the mesh but could not form a biofilm (Fig. 6D).
Affiliation: BioSystems and Micromechanics IRG, Singapore-MIT Alliance for Research and Technology, National University of Singapore, Singapore.