Figure 3

Culture conditions inducing sexual differentiation result in increased number of multinucleated-schizont stage parasites expressing Pfnek-4. Dot plots representations of GFP and propidium iodide (PI) fluorescence intensity of Pfnek-4-GFP 3D7 (upper panels) and F12 (lower panels) transfectants grown for four days either in standard culture conditions (low parasitaemia and every second-day dilution) or in conditions known to induce commitment to gametocytogenesis (high haematocrit blood cultures and high parasitaemia). Cells were fixed with 0.025% glutaraldehyde, stained for DNA with the fluorescent dye propidium iodide (PI) and subsequently analysed by a FACScan flow cytometer (Becton Dickinson). Uninfected red blood cells with low FL-2 (PI) fluorescence were excluded from the selection. Parasite numbers are given related to total number of infected red cells.