FIG. 4.

Morphology of the living acanthamoebae at different time points after the induction of encystation. (a to d) Control culture. (a) Twelve hours after the induction of encystation, the trophozoites are detaching from the flask and starting to round up. (b) Twenty-four hours after the induction of encystation, immature cysts with a single-layered cyst wall are present; the first mature cysts with both layers of the cyst wall are also shown. (c and d) From 48 to 72 h after the induction of encystation, the number of mature cysts with both walls gradually increases, and at 72 h, the population of acanthamoebae consists mainly of mature cysts. (e to h) siRNA-treated cultures. (e) Twelve hours after the induction of encystation, trophozoites are starting to round up, similar to those in the control culture. (f) Twenty-four hours after the induction of encystation, single-layered “pseudocysts” are observed as a main cell type. (g) No mature cysts are observed 48 h after the induction of encystation. The main cell type present is the single-layered immature cyst. (h) Immature cysts represent approximately 70% of the cell population; the first mature cysts are also observed. T, trophozoite; PC, immature precyst; C, mature cyst. Scale bar, 10 μm.