Malaria continues to be a scourge on the tropical world, afflicting 200-300 million people a year, killing about 2 million. With the evolution of chloroquine-resistant strains of P. falciparum and efficacious malaria vaccines still many years away, new strategies based on recent developments in the biochemistry of malarial parasites may open pharmacological inroads into the chemotherapy of this endemic disease. Symptomatic malarial disease is cause by asexual parasites that proliferate during the erythrocytic stage of the malarial life cycle. Interference with 1) the process by which a merozoite invades an erythrocyte of 2) the biochemical mechanisms which govern intracellular maturation and proliferation of the parasite which are obligate for survival, could arrest or ameliorate this disease. Toward this end, three specific aims will be pursued firstly, the mechanism of invasion of the erythrocyte will be probed by labeling infectious merzoites and/or erythrocytes with fluorescent phopholipids and observing the events which transpire; (i, e., exchange of lipid, invagination of the erythrocyte, etc.) by laser-scanning confocal fluorescence imaging microscopy (CFIM). using this technique, visualization of the fluorescence which arises from the fluorescent phopholipids incorporated into the merozoite and erythrocyte membranes allows examination of the invasion event at the single cell level. CFIM will also definitively show the origin of the parasitophorous vacuole membrane (PVM). Stage-specific P. falciparum infected erythrocytes will be labeled with fluorescent lipids of varying class to identify the lipid trafficking or sorting pathways between the erythrocyte, PVM and parasite membranes. Fluorescence imaging microscopy will aid in the identification of new membranous structures in the infected erythrocyte cytoplasm. The effects of anti-malarial agents on lipid uptake, synthesis and membrane trafficking will also be investigated to better understand their mode of action. Application of these new strategies and techniques to malaria will give considerable new insight into (membrane) biochemistry of this disease and may ultimately provide the basic for the development of new anti-malarial chemotherapeutic agents and treatment regimens.
