Glucosyltransferase phase variation in Streptococcus gordonii modifies adhesion to saliva-coated hydroxyapatite surfaces in a sucrose-independent manner

Authors

  • M. M. Vickerman,

    1. Department of Cariology and General Dentistry, University of Michigan, Ann Arbor, USA
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  • D. B. Clewell,

    1. Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, USA
    2. Department of Microbiology and Immunology, School of Medicine, University of Michigan, Ann Arbor, USA
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  • G. W. Jones

    Corresponding author
    1. Department of Microbiology and Immunology, School of Medicine, University of Michigan, Ann Arbor, USA
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G. W. Jones, Department of Microbiology and Immunology, 6743 Medical Sciences Building 2, University of Michigan, Ann Arbor, M1 48109-0620, USA

Abstract

Phase variation of Streptococcos gordonii between high (Spp+) and low (Spp) levels of glucosyltransferase (GTF) activity resulted in the greater adhesion of Spp strains to saliva-coated hydroxyapatite (S-HA) in a washed-cell adhesion test. Specific GTF mutants did not show this response. Although washed Spp+ cells produced 5-fold or more glucan from sucrose than Spp cells did under the conditions of the adhesion test, sucrose elevated the adhesion of both phenotypes to hydroxyapatite (HA) equally, but had no effect on adhesion to S-HA. This effect was not sucrose-specific, however, because equimolar amounts of other carbohydrates and NaCl elevated adhesion of both Spp types to levels similar to those seen with sucrose. Adhesion did not correlate with relative changes in cell hydrophobicity. These results suggest that, in addition to changes in GTF activity, other changes relevant to adhesion may occur during Spp phase variation.

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