RESUMO
This study investigated the mechanism of protein attachment to the surface of the putative periodontal pathogens Prevotella intermedia and Prevotella nigrescens in artificial gingival crevicular fluid, and ways to increase protein attachment to the bacterial cells. The effects of cations on protein attachment, bacterial adhesion, and hemagglutination were examined, and cation-binding components on both bacterial species were identified. The presence of cations, especially zinc, copper and cerium, increased attachment of human serum proteins to both bacterial species. In contrast, the presence of hydrophobic inhibitors or sugars had little effect. Protein attachment was reduced by heat treatment of the bacterial cells. Pretreatment of bacteria with human serum proteins inhibited adhesion of both species to buccal epithelial cells and hemagglutination. These effects were enhanced by the presence of zinc and copper during pretreatment. Using a chelating column, specific zinc- and copper-binding proteins were identified on the surfaces of both bacterial species.