Fig 3.

SAL and GA impede reactivation of latent bradyzoites in vitro. (A) The diagram outlines the experimental setup. ME49 tachyzoites (Tz) were differentiated into bradyzoite cysts (Bz) using alkaline (pH 8.1) medium for 7 days. The alkaline stress medium was then removed and replaced with normal medium (pH 7.2) containing indicated concentrations of SAL, GA, or vehicle (DMSO) for 3 days. Alkaline medium was retained in some samples as a positive control to prevent reactivation. Reactivation was assessed by counting Dolichos lectin-stained cysts in at least 25 random fields (B) or by counting reactivated tachyzoites present in culture medium (C). (B) The histogram shows the results from a representative experiment performed in triplicate and normalized to the number of cysts counted in the vehicle control. This experiment was repeated a total of three times, each with similar results. (C) The average for three independent experiments was normalized to the number of tachyzoites present in the vehicle control. In panels A and B, error bars indicate standard deviations and asterisks indicate a statistically significant difference relative to results for the vehicle control (P < 0.05, two-tailed unpaired t test).