Figure 1

The relationship between metabolic and developmental changes during in vitro parasite culture. (A) Metabolic time-trajectory showing the first two components (PC1 and PC2) of a PCA scores plot on fresh culture medium (M) and parasite-conditioned medium from intra-erythrocytic P. falciparum cultures, throughout the 14-day culture period (D1-D14). n = 8 samples for each time-point. Coordinates and error bars represent mean averages for each time point and standard error of the mean (SEM), respectively. R² and Q² represent the values of the degrees of model fit and predictive values of the PCA model for components 1 and 2, respectively. (B) Parasite populations at culture days representing major shifts in trajectory (D1, D4, D7, D8, D14) were assessed by manual counting of Giemsa-stained culture smears (n = 3 cultures, showing mean ± SEM). Days 1-4 were typified by an increasing asexual population; Days 4-7 showed a decline in asexuals and emergence of early gametocytes; Days 7-14 showed gametocyte maturation; by Day 14, the culture consisted mainly of mature Stage V gametocytes. (C) Representative microscope images showing parasite culture composition at the culture days assessed. Scale bar = 10 μm.