Heterochromatin-dependent gene silencing is central to the adaptation and survival of Plasmodium falciparum malaria parasites, allowing clonally variant gene expression during blood infection in humans. By assessing genome-wide heterochromatin protein 1 (HP1) occupancy, we present a comprehensive analysis of heterochromatin landscapes across different Plasmodium species, strains, and life cycle...

A rapid, semiautomated microdilution method was developed for measuring the activity of potential antimalarial drugs against cultured intraerythrocytic asexual forms of the human malaria parasite Plasmodium falciparum. Microtitration plates were used to prepare serial dilutions of the compounds to be tested. Parasites, obtained from continuous stock cultures, were subcultured in these plates fo...

The human malaria parasite Plasmodium falciparum possesses a single mitochondrion and a plastid-like organelle called the apicoplast. Both organelles contain members of the KADH (alpha-keto acid dehydrogenase) complexes--multienzyme complexes that are involved in intermediate metabolism. In the asexual blood stage forms of the parasites, the alpha-ketoglutarate dehydrogenase and branched chain ...

In a previous work (WeinshalI1986), a model for competition between sexually reproducing and asexually reproducing (e.g., vegetative or parthenogenetic) individuals of the same diploid population was investigated. It was assumed that the population periodically undergoes n modes of selection (e.g., it is periodically infested by n sorts of parasite; see Haldane 1949;Maynard Smith 1978;Hamilton ...

This is the first report of molecular characterization of a novel cyclic nucleotide PDE (phosphodiesterase), isolated from the human malaria parasite Plasmodium falciparum and designated PfPDE1. PfPDE1 cDNA encodes an 884-amino-acid protein, including six putative transmembrane domains in the N-terminus followed by a catalytic domain. The PfPDE1 gene is a single-copy gene consisting of two exon...

The stage-specific antimalarial activities of a panel of antiretroviral protease inhibitors (PIs), including two nonpeptidic PIs (tipranavir and darunavir), were tested in vitro against Plasmodium falciparum. While darunavir demonstrated limited antimalarial activity (effective concentration [EC(50)], >50 microM), tipranavir was active at clinically relevant concentrations (EC(50), 12 to 21 mic...

Coccidial infection is universal in sheep and goats, and coccidiosis can be a significant problem in the young of both species. The coccidian are members of the protistan phylum Apicomplexa, subclass Coccidiasina, intracellular parasites, characterized at some stage of the life cycle by a typical apical complex of organelles at one end of the organism. Members of the genus Eimeria and Isospora ...

as previously believed. B. Tissue forms represent the intermediate stage into which the sporozoites develop and from which the asexual blood forms which produce fever arise. The sporozoites after being introduced into human body by mosquito first grow and multiply in the endothelial tissues. Such tissue forms have been demonstrated by some German workers, and James and Tate in bird malaria. Ver...

Malaria is a major disease of humans caused by protozoan parasites from the genus Plasmodium. It has a complex life cycle; however, asexual parasite infection within the blood stream is responsible for all disease pathology. This stage is initiated when merozoites, the free invasive blood-stage form, invade circulating erythrocytes. Although invasion is rapid, it is the only time of the life cy...

In nearly all non-photosynthetic cells, pantothenate (vitamin B5) transport and utilization are prerequisites for the synthesis of the universal essential cofactor Coenzyme A (CoA). Early studies showed that human malaria parasites rely on the uptake of pantothenate across the parasite plasma membrane for survival within erythrocytes. Recently, a P. falciparum candidate pantothenate transporter...