FIG. 6.

Kinetic analysis of the hemolytic activity of whole cells of P. gingivalis W83 (◊) and derivative mutants strains FLL32 (▵) and FLL92 (■). Erythrocytes were prepared by the method of Chu et al. (9). Bacterial cells were grown, pelleted, and assayed for hemolytic activity as described in the text. As a negative control (○), erythrocytes were used alone. Each value indicates average ± standard deviation (assays were performed in triplicate). Using Student's t test (Statistical Package for the Social Sciences, version 9), there is a significance difference (P > 0.05) between the wild-type strain and isogenic mutants.