Abstract
This study uses electrophoretic mobility measurements to investigate the surface of Treponema denticola ATCC 33520 and its participation in hemagglutination of erythrocytes. Both exponential and stationary phase batch cultures displayed two distinct pH-dependent electrophoretic mobilities, suggesting a cell population heterogeneity with respect to charge within a single, bacteriologically pure culture. Adsorption of a culture of T. denticola with an excess of erythrocytes removed a large proportion of the more negatively charged subpopulation. The data suggest that the more negatively charged subpopulation, which was in the minority in all spirochete cultures studied, is the portion of bacteria which are capable of adhesion to erythrocytes and that the interaction is mediated by attractive electrostatic interactions between oppositely charged domains on the interacting surfaces.