Surface hydrophobicity of small oral spirochetes

The purpose of the present study was to determine the surface hydrophobicity of small oral spirochetes and to receive an impression of the molecular organization of the cell surfaces. Nine spirochete strains with one endoflagellum from each cell-end (1:2:1 spirochetes) and eight with two endoflagella from each cell-end (2:4:2 spirochetes) from subgingival plaque were examined. Two hydrophobicity assay systems were used: 1) two-phase partitioning and 2) salting-out aggregation by ammonium sulfate. The influence of heat, enzymes, saliva, and serum were examined. The 2:4:2 spirochetes were significantly more hydrophobic than the 1:2:1 spirochetes. For all strains heat treatment increased surface hydrophobicity, whereas incubation with proteases decreased surface hydrophobicity for the 1:2:1 spirochetes. The 2:4:2 spirochetes were unaffected by the proteases. Lipase and hyaluronidase affected the two morphotypes in opposite directions. Saliva did not affect the surface hydrophobicity of any of the strains, whereas rabbit serum decreased this property for the 2:4:2 strains.