Out of the five malaria parasites that can infect humans, Plasmodium falciparum is the most lethal one. This parasite shows a complex life cycle, in which its asexual phase in blood is the responsible for the symptoms of this disease, while the sexual phase (or gametocyte) is the only that can infect the mosquito. Therefore, transmission from humans to mosquitoes requires the differentiation of some of the asexual parasites to gametocytes, a process called sexual conversion.
In an article published in the journal Science Advances, researchers from ISGlobal, the University of Barcelona and Hospital Clínic describe the technique researchers carried out to induce in vitro the massive sexual conversion of the malaria parasite P. falciparum. This system will allow researchers to design new tools to block malaria transmission.
Results show that 90% of the transgenic parasites that converted to sexual phase after the induction with rapamycin, which enables the study of the first sexual phases with no need to purify them. “Our induced sexual conversion systems creates large quantities of synchronized parasites in the first sexual developmental phases, with a purity that had not been achieved with other strategies”, notes Oriol Llorà Batlle, first author of the study and researcher at ISGlobal, UB and Hospital Clínic. The comparison of culture parasites with or without rapamycin enabled researchers identify 370 genes the expression of which increases or decreases with the sexual conversion.
O. Llorà-Batlle, L. Michel-Todó, K. Witmer et al. "Conditional expression of PfAP2-G for controlled massive sexual conversion in Plasmodium falciparum". Science Advances, June, 2020. Doi: 10.1126/sciadv.aaz5057