Actin filament rearrangement is essential for P. gingivalis invasion of osteoblasts. A. Osteoblast nuclei, actin and P. gingivalis are indicated by blue, red or green fluorescence, respectively. No appreciable change in actin filament organization was seen 30 min after infection. At 3 h, actin relocated to the periphery of the osteoblasts, leaving a void space surrounding the osteoblast nuclei occupied by P. gingivalis. Twenty-four hours after infection, actin became more condensed and formed a cortical outer shell. The number of perinuclear P. gingivalis was also significantly increased. Addition of the actin disrupting agent, cytochalasin D, reduced the number of osteoblasts with P. gingivalis invasion. Notice that actin had now become disorganized, as demonstrated by the punctuated pattern. B. Quantitative analysis of confocal images demonstrated that P. gingivalis invasion of osteoblasts was inhibited by the disruption of actin filaments. Abbreviations: min, minute; h, hour; Ctrl and CT, control, non-infected osteoblasts; PG, P. gingivalis. Scale bar = 20 μm. * denotes P < 0.05.
Zhang et al. BMC Microbiology 2013 13:5 doi:10.1186/1471-2180-13-5