FIG 2.

P. gulae induces apoptosis and death in oral epithelial cells. (A) Apoptosis was measured as an increase in green fluorescence (Yo-Pro-1), and cell death was measured as an increase in green and red (PI) fluorescence. (B) All bacteria tested induced apoptosis; however, P. gingivalis ATCC 33277 () and P. gulae ATCC 51700 (□) induced significantly more apoptosis than did P. gingivalis W50 (■). (C) All bacteria induced similar levels of cell death (PI) at the time point measured. Means ± the SEM are shown (*, P < 0.05; **, P < 0.005 [P. gulae and P. gingivalis ATCC 33277 versus P. gingivalis W50; n = 3]).