“…This study is one of only a few since 1975 to investigate the structure and molecular make-up of Plasmodium CVCs (Aikawa et al , 1975; Barnwell et al , 1990; Barnwell, 1986; Aikawa et al , 1977; Atkinson et al , 1990; Bracho et al , 2006; Udagama et al , 1988; Matsumoto et al , 1988; Matsumoto et al , 1986) and the first to present these structures in 3-D. The ET imaging results presented here corroborate previous TEM reports showing numerous CVCs interspersed along the surface of the P. vivax and P. cynomolgi iRBCs with their caveolae open to the surface (Aikawa et al , 1975).…”
Summary
Plasmodium vivax and P. cynomolgi produce numerous caveolae-vesicle complex (CVC) structures within the surface of the infected erythrocyte membrane. These contrast with the electron-dense knob protrusions expressed at the surface of P. falciparum infected erythrocytes. Here we investigate the 3-dimensional structure of the CVCs and the identity of a predominantly expressed 95 kDa CVC protein. Liquid chromatography - tandem mass spectrometry analysis of immunoprecipitates by monoclonal antibodies from P. cynomolgi extracts identified this protein as a member of the Plasmodium helical interspersed sub-telomeric (PHIST) superfamily with a calculated mass of 81 kDa. We named the orthologous proteins PvPHIST/CVC-8195 and PcyPHIST/CVC-8195, analyzed their structural features, including a PEXEL motif, repeated sequences and a C-terminal PHIST domain, and show that PHIST/CVC-8195 is most highly expressed in trophozoites. We generated images of CVCs in 3-D using electron tomography, and used immuno-Electron Tomography (ET) to show PHIST/CVC-8195 localizes to the cytoplasmic side of the CVC tubular extensions. Targeted gene disruptions were attempted in vivo. The pcyphist/cvc-8195 gene was not disrupted, but parasites containing episomes with the tgdhfr selection cassette were retrieved by selection with pyrimethamine. This suggests that PHIST/CVC-8195 is essential for survival of these malaria parasites.
“…This study is one of only a few since 1975 to investigate the structure and molecular make-up of Plasmodium CVCs (Aikawa et al , 1975; Barnwell et al , 1990; Barnwell, 1986; Aikawa et al , 1977; Atkinson et al , 1990; Bracho et al , 2006; Udagama et al , 1988; Matsumoto et al , 1988; Matsumoto et al , 1986) and the first to present these structures in 3-D. The ET imaging results presented here corroborate previous TEM reports showing numerous CVCs interspersed along the surface of the P. vivax and P. cynomolgi iRBCs with their caveolae open to the surface (Aikawa et al , 1975).…”
Summary
Plasmodium vivax and P. cynomolgi produce numerous caveolae-vesicle complex (CVC) structures within the surface of the infected erythrocyte membrane. These contrast with the electron-dense knob protrusions expressed at the surface of P. falciparum infected erythrocytes. Here we investigate the 3-dimensional structure of the CVCs and the identity of a predominantly expressed 95 kDa CVC protein. Liquid chromatography - tandem mass spectrometry analysis of immunoprecipitates by monoclonal antibodies from P. cynomolgi extracts identified this protein as a member of the Plasmodium helical interspersed sub-telomeric (PHIST) superfamily with a calculated mass of 81 kDa. We named the orthologous proteins PvPHIST/CVC-8195 and PcyPHIST/CVC-8195, analyzed their structural features, including a PEXEL motif, repeated sequences and a C-terminal PHIST domain, and show that PHIST/CVC-8195 is most highly expressed in trophozoites. We generated images of CVCs in 3-D using electron tomography, and used immuno-Electron Tomography (ET) to show PHIST/CVC-8195 localizes to the cytoplasmic side of the CVC tubular extensions. Targeted gene disruptions were attempted in vivo. The pcyphist/cvc-8195 gene was not disrupted, but parasites containing episomes with the tgdhfr selection cassette were retrieved by selection with pyrimethamine. This suggests that PHIST/CVC-8195 is essential for survival of these malaria parasites.
“…These parasites naturally infect monkeys from the families Cebidae and Atelidae. P. simium and P. brasilianum are similar to human P. vivax and P. malariae , respectively, and these similarities occur at the morphological, genetic, and immunological level [3, 11–14, 20, 21, 24, 26, 27, 30, 34].…”
These results suggest that a possible interaction between human and simian malaria coming from a zoonotic cycle cannot be discarded because simians that live in the areas of the Atlantic Forest could play a role as a reservoir for Plasmodium.
“…Similarities in morphological and immunological responses between P. vivax and P. simium [3, 5, 10, 17, 27] and P. malariae and P. brasilianum were reported [5–7, 19]. Molecular and phylogeny studies based on 18S ribosomal subunit RNA (ssrRNA), the circumsporozoite protein (CSP) gene and cytochrome b gene of P. malariae / P. brasilianum [14, 15, 23], P. vivax / P. simium [14, 18] and human P. vivax ‐like/ P. simiovale [13] showed that they are not distinct and that P. falciparum / P. reichenowi (a parasite of Pan troglodytes , an Old World ape) are very closely related [13, 14, 21].…”
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