Fig. 2

Inter-study variation in metabolomic data from uninfected red blood cells (uRBC) of the five studies and parasite-infected red blood cells (iRBC). A Principal component analysis (PCA) of metabolomic data after normalization with the 0-h time point and the identified internal standard. For each time point, there are four data points corresponding to the quadruplicate samples of each study. B PCA of averaged metabolomic data after normalization with the 0-h time point and the identified internal standard. The red arrows denote separation of iRBC data from the uRBC as time progresses, indicated by light to dark red, while the blue arrow denotes separation within the uRBC data. Abscissa and ordinate in A and B denote the percentage of the total data variance explained by each principal component. C Raw differences between normalized data from uRBC cultures and the iRBC culture. The difference was taken within uRBC data for each time point (blue circles) or between uRBC data and iRBC data for each time point (red circles). The table in the inset shows the average differences. Note that for PCA and difference computations, we did not include the 0-h data, as they serve as the comparator for other time points. + Fos, fosmidomycin-added RPMI medium; -Hxn, hypoxanthine-deprived RPMI medium; + Mev, mevalonate-added RPMI medium; PC1, first principal component; PC2, second principal component; Pure 1, pure RPMI medium; Pure 2, pure RPMI medium; RPMI, Roswell Park Memorial Institute; SD, standard deviation