title: Characterization of permeation pathways appearing in the host membrane of Plasmodium falciparum infected red blood cells.
abstract: The host cell membrane of Plasmodium falciparum infected cells becomes permeabilized at the trophozoite stage. A variety of otherwise impermeant substances such as carbohydrates, polyols, amino acids and anions easily gain access to the cytosol of infected cells. Using the isotonic-hemolysis method or uptake of labeled substances, we characterized the new permeation pathways as pores of approximately 0.7 nm equivalent radius. The pores bear a positively charged character which facilitates movement of small anions and excludes cations, so that the ionic composition and osmotic properties of infected cells are not drastically altered. Substances of a molecular size similar to that of disaccharides are fully excluded. Substances of limiting size might be accommodated in the pore, provided they bear a side group of hydrophobic character. The new permeation pathways may provide a vital route for acquisition or release of essential nutrients or catabolites.
mesh_terms: D000596:Amino Acids / Q000097:blood; D000818:Animals; D001693:Biological Transport, Active; D002241:Carbohydrates / Q000097:blood; D002463:Cell Membrane Permeability; D004912:Erythrocytes / Q000378:metabolism / Q000469:parasitology*; D006461:Hemolysis; D006801:Humans; D066298:In Vitro Techniques; D008288:Malaria / Q000097:blood / Q000469:parasitology*; D010963:Plasmodium falciparum
chemical_list: D000596:Amino Acids; D002241:Carbohydrates