Figure 4

Carrier grown biofilm visualized by FISH. Hybridization was performed with the probes EUB 338-Cy5 (magenta) and FIAL-Cy3 (bright orange) along with DAPI staining (blue) on a carrier after 7 days of attachment to the mesial aspect of tooth 16 in a GAP patient. (a): Collage of several microscopic fields in low magnification. The overlay of Cy3, Cy5 and DAPI filter sets shows the bacterial biofilm that grew in the depth of the pocket. EUB 338 visualizes large parts of the bacterial community, while FIAL detects only F. alocis. DAPI stains both host cell nuclei and bacteria. The carrier tip (1) and the carrier side facing the tooth (2) show little or no presence of F. alocis. The bright orange signal on the carrier side facing the pocket epithelium (3) reveals a strong presence of Filifactor in the part of the biofilm indicated by the arrow. Arrowheads on the tooth side (2) point to artifacts caused by upfolding of the embedded carriers. (b and c): Higher magnifications of the inserts. (b) shows the biofilm on the tooth side of the carrier without F. alocis among the bacteria. (c) shows F. alocis in densely packed groups among the organisms on the epithelium side and host cell nuclei (blue).