Transcriptome analyses of the ex vivo cultured P. falciparum parasites. (a) Transcriptomes of the ex-vivo IDC of 6 field isolates (representative set of total 11 transcriptomes generated in this study; Additional file 3) from the 3 geographical locations over 48 hour sampling time. The heat maps represent the mean-centered log2 microarray expression ratios for the P. falciparum genes that were ordered according to the phase calculated by the Fast Fourier Transformation for the reference in vitro IDC transcriptome. (b) Age estimate of the ex vivo culture time points for all 11 field isolates. Each colored box represents age estimate (hpi; shown by numbers outside the circle) of the isolate sample relative to the in vitro reference IDC transcriptome calculated as a best fit Correlation (Spearman rank, see materials and methods). Indicated within each box is the sampling collection time with respect to the first sampling time denoted by 0 h that correspond to the initial sample collection from the infected patients prior to culturing. Sampling times with * represent Spearman Rank correlation value less than 0.35 which indicates a deteriorating synchronicity in the later IDC time points and were excluded from the analysis. Time points included in 3 windows (yellow frame) corresponding to rings at 12-16 hpi, trophozoites at 24 to 28 hpi and schizonts at 32 to 36 hpi were selected for further analysis. (c) Clusters of genes with significant differential expression (p-value < 0.01) between the resistant (grey) and susceptible (orange) parasites at ring (14 hpi), trophozoite (26 hpi) and schizont (34 hpi) stages. Shown are the mean-centered expression log2 ratios for these genes ranked by the z-score based on the differential expression between the resistant and susceptible isolates. Graphs represent the frequency distribution of the peak abundance time in the IDC transcriptome for each group of genes: over-expressed (red bars), under-expressed (green bars) or no significant change in expression (yellow bars). The grey lines represent the middle of the time IDC interval used for the analysis (e.g. ring, (14 hpi), trophozoite (26 hpi) and schizonts (34 hpi).
Mok et al. BMC Genomics 2011 12:391 doi:10.1186/1471-2164-12-391