Transcriptional profiling of growth perturbations of the human malaria parasite Plasmodium falciparum

The microarray experiments were carried out using a long oligonucleotide DNA microarray that represent all 5363 P. falciparum genes with one oligonucleotide per 1.9kb of coding sequence on average (Hu et al. 2007). Total 247 microarray experiments were carried out including 29-drug treatment time courses with 20 compounds and corresponding untreated controls from different drug or inhibitor treatment. Data of each drug/inhibitor experiment were normalized using a linear normalization and background filtering as implemented by the NOMAD database (http://derisilab.ucsf.edu). Time-series sampling and experiments with synchronized ex vivo culturing parasites. Each experiment has treatment and controls, and starts at a specific time of post invasion. For an example of quinine treatment, the treatments start from late ring stage through trophozoite stage of the parasites. First, IC50 is determined by drug assay with synchronized parasites (5% parasiteomia and 2% RBC). Second, synchronized parasite cultures are splitted into 12 flasks (75ml culture/flask) for a 6 time-point time-series experiment. 6 flasks are treated with quinine (final concentration is IC50) and 6 flasks are negative controls. 1,2,4,6,8 and 10 hrs after the treatment, parasites in each flask were harvested for total RNA isolation and microarray hybridizaiton.