Purification and characterization of a novel type of fimbriae from the oral anaerobe Bacteroides gingivalis

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Abstract
Fimbriae and their constituent protein (fimbrilin) were purified to homogeneity from the bacterial wash fluid and cell lysate fraction, respectively, of B. gingivalis 381. Fimbriae, observed by negative staining, were curly, single-stranded filaments with a diameter of .apprx. 5 nm. The apparent MW of the fimbrilin was 43,000. Fimbriae were resistant to sodium dodecyl sulfate denaturation at 70.degree. C. Heating at 100.degree. C in sodium dodecyl sulfate was needed to completely dissociate them to monomers of fimbrilin. Different sets of antigenic determinants seemed to be exposed on the surfaces of fimbriae and sodium dodecyl sulfate-denatured fimbrilin. Purified fimbriae did not show hemagglutinating activity or hemagglutination inhibitory activity, although it has been inferred on the basis of circumstantial evidence that fimbriae are correlated to hemagglutinating activity of the organism. Hemagglutinin activity was detected in culture supernatant, suggesting that fimbriae of a different type or a lectin-like protein may act as hemagglutinin in B. gingivalis.