FIG 3.

Parthenin decreases the number of exflagellation center events. Each bar represents the percent change in mean exflagellation levels compared to that of the acetone control (normalized to 100% exflagellation). The mean numbers of exflagellation centers were counted across 30 fields at a total magnification of ×200 at 16 to 18 min postinduction; error bars represent the normalized standard errors of the means. We found that 100- to 12.5-μg/ml doses were statistically significant at both parasite concentrations (P < 0.05), using a repeated-measures ANOVA with a Dunnett's posttest. At 1% gametocytemia, all six concentrations of parthenin were statistically significant, and for 0.5% gametocytemia, concentrations higher than 12.5 μg/ml were statistically significant. For all concentrations combined, a P value of <0.0001 and R value of 0.695 were obtained using a stepwise method for linear regression analyses.