FIG. 3.

Biofilm formation assay in PVC plates. P. gingivalis strains were incubated overnight in TSB medium diluted with PBS (TSB/PBS ratio, 1:2) with supplementation of hemin, vitamin K in the wells of 96-well PVC microtiter dishes (100 μl/well). The resulting biofilms were analyzed as described previously (24). Biofilm formation was calculated as follows: (OD₅₇₀ for the biofilm)/(OD₅₇₀ of total cell growth). The data are averages of triplicate assays with the standard errors of the means. T75, 75 phosphate polymer of polyP (100 μg/ml); PS, polyvinyl sulfate (100 μg/ml).