Fig. 1.

(a) Intercellular translocation of P. gingivalis through actin fibres at 24 h post-infection visualized by immunofluorescence microscopy. The actin cytoskeleton is stained red and P. gingivalis is green. DAPI (blue) was used to stain the nuclei to determine the localization of P. gingivalis in the cytoplasm. The white arrow indicates actin projections and bacterial translocation between the host cells. Bar, 10 µm. [This panel is reproduced from Yilmaz et al. (2006) with permission from the American Society for Microbiology.] (b) P. gingivalis spreading visualized by immunofluorescence microscopy. After 24 h co-incubation of initially 24 h-infected cells (blue) with initially uninfected cells (green), transmission of P. gingivalis to newly infected cells (green) can be seen, displaying red-labelled P. gingivalis in their cytosol. White arrows indicate newly infected cells. Bar, 10 µm.