Fig. 5.

Cells of family Pasteurellaceae adhere to S. mitis/oralis/infantis and S. cristatus but not Porphyromonas. In addition to the layer of cells of Streptococcus sp. or Porphyromonas sp. directly adjacent to the central filament, a second layer of cells from the family Pasteurellaceae is sometimes observed on corncobs. We observed these cells attached to corncobs in which the inner layer of cells was S. cristatus (A), S. mitis/oralis/infantis (B), or a mixture of S. cristatus and S. mitis/oralis/infantis (C). We also observed a second layer on mixed corncobs that included Porphyromonas sp.; in these corncobs the Pasteurellaceae cells were adjacent to Streptococcus cells but not to the nearby Porphyromonas cells (D). In the samples analyzed, we did not observe any layer of Pasteurellaceae attached to pure Porphyromonas corncobs. Among the 5 μm corncob segments counted on the samples hybridized with probe set 1, 21.1% presented a second layer formed by Pasteurellaceae (E). Of these, close to half (47%) were 5 μm segments in which all the Streptococcus cells were S. cristatus; 30% of the segments consisted of pure S. mitis/oralis/infantis; and the Streptococcus population of the remaining 23% was mixed or unidentified