Fig. 4.

Biofilm formation by mono- and cocultures of Filifactor alocis and P. gingivalis ATCC 33277 (PG). Overnight cultures of F. alocis and/or P. gingivalis were diluted with fresh BHI medium to obtain a concentration of 5 × 10⁷ CFU/ml. The cells were aliquoted to a 96-well microtiter plate (260 μl per well) and incubated anaerobically at 37°C for 24 h. The biofilms were stained with crystal violet. The solubilized crystal violet was transferred to a new microtiter plate, and the OD₅₄₀ was determined spectrophotometrically. Medium and P. gingivalis W83 were used as controls. Coculture was statistically compared with P. gingivalis monoculture.