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A factor from Actinomyces viscosus T14V that specifically aggregates Streptococcus sanguis H1

J Mizuno, J O Cisar, A E Vatter

    Infection and Immunity
    |June 1, 1983
    PubMed

    Insights

    A specific aggregation factor (AFH1) from Actinomyces viscosus T14V promotes Streptococcus sanguis H1 aggregation. This interaction involves carbohydrate-protein binding and electrostatic forces, suggesting a novel mechanism for bacterial coaggregation.

    Area of Science:

    • Microbiology
    • Bacterial Adhesion
    • Oral Microbiome

    Background:

    • Streptococcus sanguis H1 and Actinomyces viscosus T14V are oral bacteria known to coaggregate.
    • The specific molecular mechanisms underlying this coaggregation are not fully understood.

    Purpose of the Study:

    • To isolate and characterize the aggregation factor responsible for S. sanguis H1 aggregation by A. viscosus T14V.
    • To elucidate the molecular basis of this specific bacterial aggregation.

    Main Methods:

    • Lysozyme treatment of A. viscosus T14V to obtain the aggregation factor (AFH1).
    • Gel chromatography for fractionating AFH1.
    • Antigenic analysis using anti-A. viscosus T14V serum.
    • Chemical composition analysis of AFH1 fractions.
    • Inhibition assays using periodate, heat, pronase, and varying NaCl concentrations.

    Main Results:

    • A highly specific aggregation factor for S. sanguis H1 (AFH1) was isolated.
    • AFH1 primarily consists of cell wall components and polysaccharides, with a minor protein fraction.
    • Aggregation was inhibited by periodate, heat, pronase, and electrostatic interactions, suggesting a carbohydrate-protein mechanism.
    • Smaller molecular weight fractions inhibited aggregation, indicating complex interactions.

    Conclusions:

    • A novel aggregation factor (AFH1) from A. viscosus T14V mediates specific aggregation of S. sanguis H1.
    • The interaction is likely driven by carbohydrate-protein binding and influenced by electrostatic forces.
    • This finding provides insights into the molecular mechanisms of oral bacterial coaggregation.

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