Luciferase activity of plasmid constructs showing the reporter gene activity at the three asexual blood stages of P. falciparum . Ring stage parasites transfected with 75 μg of plasmids containing the 1 kb construct of falcipain 1 and 2 kb constructs of falcipain2, 2' and 3. Co-transfection with 75 μg of renilla served as internal control for the transfection assays. Luciferase assays were performed at 48 h, 75 h, 96 h post transfection. The luciferase gene is indicated as box. Percentage relative luciferase activity was calculated by normalizing the luciferase firefly to the renilla internal control values. The values shown represent the mean ± standard deviation of two independent transfection experiments performed in triplicates.