title: Streptococcus gordonii comCDE (competence) operon modulates biofilm formation with Candida albicans.
abstract: Candida albicans is a pleiomorphic fungus that forms mixed species biofilms with Streptococcus gordonii, an early colonizer of oral cavity surfaces. Activation of quorum sensing (QS; intercellular signalling) promotes monospecies biofilm development by these micro-organisms, but the role of QS in mixed species communities is not understood. The comCDE genes in S. gordonii encode a sensor-regulator system (ComDE), which is activated by the comC gene product (CSP, competence stimulating peptide) and modulates expression of QS-regulated genes. Dual species biofilms of S. gordonii ΔcomCDE or ΔcomC mutants with C. albicans showed increased biomass compared to biofilms of S. gordonii DL1 wild-type with C. albicans. The ΔcomCDE mutant dual species biofilms in particular contained more extracellular DNA (eDNA), and could be dispersed with DNase I or protease treatment. Exogenous CSP complemented the S. gordonii ΔcomC transformation deficiency, as well as the ΔcomC-C. albicans biofilm phenotype. Purified CSP did not affect C. albicans hyphal filament formation but inhibited monospecies biofilm formation by C. albicans. The results suggest that the S. gordonii comCDE QS-system modulates the production of eDNA and the incorporation of C. albicans into dual species biofilms.
authors.affiliation: School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, UK.
authors.forename: Alison A
authors.initials: AA
authors.lastname: Jack
authors.affiliation: School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, UK.|School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, UK.
authors.forename: Debbie E
authors.initials: DE
authors.lastname: Daniels
authors.affiliation: School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, UK.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Jepson
authors.affiliation: Department of Oral Biology, University at Buffalo, 223 Foster Hall, Buffalo, NY 14214, USA.
authors.forename: M Margaret
authors.initials: MM
authors.lastname: Vickerman
authors.affiliation: Center for Oral Health and Systemic Disease, University of Louisville School of Dentistry, 501 South Preston Street, Louisville, KY 40202, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Lamont
authors.affiliation: School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, UK.
authors.forename: Howard F
authors.initials: HF
authors.lastname: Jenkinson
authors.affiliation: School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, UK.
authors.forename: Angela H
authors.initials: AH
authors.lastname: Nobbs
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms; D002176:Candida albicans / Q000235:genetics / Q000502:physiology*; D002177:Candidiasis / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009876:Operon; D053038:Quorum Sensing; D013290:Streptococcal Infections / Q000382:microbiology*; D054773:Streptococcus gordonii / Q000235:genetics / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial