Scanning electron micrograph of the Prevotella intermedia cell surface

Abstract

     We examined scanning electron micrographs using Prevotella intermedia cells isolated from infectious oral diseases. Cell fringes were observed after staining with uranyl acetate. Scales (particles) on the cell surface could be clearly observed on samples fixed with glutaraldehyde and OsO₄. Fluffy structures were rarely observed on the surface of the various strains. Bacterial cells adhered to the surface of aluminum foil by string like structures. However, bacterial cells that adhered to red blood cells did not have these structures. The number of scales on the cell surface in freeze substitution samples was less than that for the double fixation samples. Freeze substituted cells were covered with viscous material and secretions during incubation, but fluffy structures were not observed.
     We found the freeze substitution method better than other techniques for observing cell surfaces that are very close to fresh cell.