Iron uptake and metabolism in malaria parasite

Abstract

Iron uptake study of P.berghei-infected cells was investigated both in vitro and in vivo. The results showed no enhanced iron uptake by the infected cells in both system. Various sugar showed no effect on the iron uptake. Possible existence and the presence of specific iron chelator (Plasmodial siderophore) in the lysated of infected cells was evidenced, Iron mobilization studies showed that deproteinized infected lysate could chelate the iron from chrome azurol S-ferric complex and transferrin. More significantly, ferritin iron was strongly chelated by the infected lysates (both P.berghei and P.falciparum) The results suggested that ferritin iron might be serving as endogenous iron source for the parasite and that the lysates possibly contained parasite-derived iron chelator for iron aquisition. Organic solvent extraction showed that the iron chelator (Plasmodial siderophore) was extractable with benzyl alcohol but not with ethyl acetate. The results suggested the presence of hydroxamate type siderophore in the infected lysata. Methonol/water (1:1) was found to be suitable solvent for characterizing the plasmodial siderophores by paper chromatography. The R(,f) value of 0.44 for the infected lysate was found to be different from that of DFO (= 0.94) while the uninfected lysate remained at the origin. Iron competitive mobilization study showed desferrioxamine to be stronger chelator than that of the parasite. The results of this study suggested that intraerythrocytic parasite might be dependent on ferritin iron. The iron acquisition was probably by means of parasite siderophore. The siderophore was of hydroxamate type low molecular weight compound with R(,f) of 0.44 in paper chromatography with methanol/water (1:1) as solvent system.