Plasmodium falciparum is a purine auxotroph. The transport of purine nucleosides and nucleobases from the host erythrocyte to the parasite cytoplasm is essential to support parasite growth. P. falciparum equilibrative nucleoside transporter 1 (PfENT1) is a major route for purine transport across the parasite plasma membrane. Malarial parasites are sensitive to inhibitors of purine salvage pathway enzymes. The immucillin class of purine nucleoside phosphorylase inhibitors and the adenosine analog, tubercidin, block growth of P. falciparum under in vitro culture conditions. We sought to determine whether these inhibitors utilize PfENT1 to gain access to the parasite cytosol.
We have analyzed the in vitro chemosensitivity profiles of 115 Kenyan isolates for chloroquine (CQ), piperaquine, lumefantrine (LM), and dihydroartemisinin in association with polymorphisms in pfcrt at codon 76 and pfmdr1 at codon 86, as well as with variations of the copy number of pfmdr1.
Quinine has been employed in the treatment of malaria for centuries and is still used against severe Plasmodium falciparum malaria. However, its interactions with the parasite remain poorly understood and subject to debate. In this study, we used the Saccharomyces cerevisiae eukaryotic model to better understand quinine's mode of action and the mechanisms underlying the cell response to the drug.
The evolution of resistance in Plasmodium falciparum against safe and affordable drugs such as chloroquine (CQ) and sulfadoxine-pyrimethamine (SP) is a major global health threat. Investigating the dynamics of resistance against these antimalarial drugs will lead to approaches for addressing the problem of resistance in malarial parasites that are solidly based in evolutionary genetics and population biology. In this article, we discuss current developments in population biology modeling and evolutionary genetics.
Sulfadoxine-pyrimethamine (SP) resistance in Plasmodium falciparum has been widespread across continents, causing the major hurdle of controlling malaria. Resistance is encoded mainly by point mutations in P. falciparum dihydrofolate reductase (pfdhfr) and dihydropteroate synthase (pfdhps) target genes. To study the origin and evolution of pyrimethamine resistance on the Indian subcontinent, microsatellite markers flanking the pfdhfr gene were mapped. Here we describe the characteristics of genetic hitchhiking around the pfdhfr gene among 190 P. falciparum isolates.
Hemoglobin (Hb) degradation is essential for the growth of the intraerythrocytic stages of malarial parasites. This process, which occurs inside an acidic digestive vacuole (DV), is thought to involve the action of four aspartic proteases, termed plasmepsins (PMs). These enzymes have received considerable attention as potential antimalarial drug targets.
The findings support the view that placental parasitization is significantly associated with partial maturation of different dendritic cell subsets and also to slightly increased responses to TLR9 ligand in cord blood.
A description of allele frequencies of two polymorphic P. falciparum surface antigens from two sites of varying transmission intensity, Papua New Guinea and Tanzania. It confirms previous reports of a higher mean multiplicity of infection and increased genetic diversity in areas of higher endemicity.