title: Cholate-stimulated biofilm formation by Lactococcus lactis cells.
abstract: Bile acid resistance by Lactococcus lactis depends on the ABC-type multidrug transporter LmrCD. Upon deletion of the lmrCD genes, cells can reacquire bile acid resistance upon prolonged exposure to cholate, yielding the ΔlmrCD(r) strain. The resistance mechanism in this strain is non-transporter based. Instead, cells show a high tendency to flocculate, suggesting cell surface alterations. Contact angle measurements demonstrate that the ΔlmrCD(r) cells are equipped with an increased cell surface hydrophilicity compared to those of the parental and wild-type strains, while the surface hydrophilicity is reduced in the presence of cholate. ΔlmrCD(r) cells are poor in biofilm formation on a hydrophobic polystyrene surface, but in the presence of subinhibitory concentrations of cholate, biofilm formation is strongly stimulated. Biofilm cells show an enhanced extracellular polymeric substance production and are highly resistant to bile acids. These data suggest that non-transporter-based cholate resistance in L. lactis is due to alterations in the cell surface that stimulate cells to form resistant biofilms.
authors.affiliation: Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute and the Kluyver Centre for Genomics of Industrial Fermentation, University of Groningen, Nÿenborgh 7, 9747 AG Groningen, Netherlands.
authors.forename: Arsalan Haseeb
authors.initials: AH
authors.lastname: Zaidi
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Bakkes
authors.forename: Bastiaan P
authors.initials: BP
authors.lastname: Krom
authors.forename: Henny C
authors.initials: HC
authors.lastname: van der Mei
authors.forename: Arnold J M
authors.initials: AJ
authors.lastname: Driessen
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D001647:Bile Acids and Salts / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D002462:Cell Membrane / Q000187:drug effects; D020355:Cholates / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D057927:Hydrophobic and Hydrophilic Interactions; D013294:Lactococcus lactis / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; D001647:Bile Acids and Salts; D020355:Cholates; D026901:Membrane Transport Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; C513418:LmrC protein, Lactococcus lactis; C513419:LmrD protein, Lactococcus lactis