Three members of the 6-cys protein family of Plasmodium play a role in gamete fertility.

The process of fertilization is critically dependent on the mutual recognition of gametes and in Plasmodium, the male gamete surface protein P48/45 is vital to this process. This protein belongs to a family of 10 structurally related proteins, the so called 6-cys family. To identify the role of additional members of this family in Plasmodium fertilisation, we performed genetic and functional analysis on the five members of the 6-cys family that are transcribed during the gametocyte stage of P.

Plasmodium cysteine repeat modular proteins 1-4: complex proteins with roles throughout the malaria parasite life cycle.

The Cysteine Repeat Modular Proteins (PCRMP1-4) of Plasmodium, are encoded by a small gene family that is conserved in malaria and other Apicomplexan parasites. They are very large, predicted surface proteins with multipass transmembrane domains containing motifs that are conserved within families of cysteine-rich, predicted surface proteins in a range of unicellular eukaryotes, and a unique combination of protein-binding motifs, including a >100 kDa cysteine-rich modular region, an epidermal growth factor-like domain and a Kringle domain. PCRMP1 and 2 are expressed in life cycle stages in both the mosquito and vertebrate.

Malaria transmission-blocking antigen, Pfs230, mediates human red blood cell binding to exflagellating male parasites and oocyst production.

Malaria transmission requires that the parasites differentiate into gametocytes prior to ingestion by a mosquito during a blood meal. Once in the mosquito midgut the gametocytes emerge from red blood cells (RBCs), fertilize, develop into ookinetes and finally infectious sporozoites. Gamete surface antigen, Pfs230, is an important malaria transmission-blocking vaccine candidate, but its function has remained unclear.

Liver-stage development of Plasmodium falciparum, in a humanized mouse model.

Background: The liver stage of the human malaria parasite Plasmodium falciparum is the least known, yet it holds the greatest promise for the induction of sterile immunity and the development of novel drugs. Progress has been severely limited by the lack of adequate in vitro and in vivo models.

Methods: Recently, it was found that immunodeficient mice transgenic for the urokinase plasminogen activator allow survival of differentiated human hepatocytes.

Quantification of Plasmodium falciparum gametocytes in differential stages of development by quantitative nucleic acid sequence-based amplification.

Two quantitative nucleic acid sequence-based amplification assays (QT-NASBA) based on Pfs16 and Pfs25, have been developed to quantify sexual stage commitment and mature gametocytes of Plasmodium falciparum. Pfs16 mRNA is expressed in all sexual forms including sexually committed ring stages while expression of Pfs25 mRNA is restricted to late stage gametocytes. Both assays showed a sensitivity of one sexual stage parasite/microl of blood.

Transmission of Plasmodium falciparum in urban Yaoundé, Cameroon, is seasonal and age-dependent.

Data on malaria transmission intensity and prevalences of asexual parasites and of gametocytes were obtained in an urban district of Yaoundé, Cameroon. The transmission level from mosquito to human was determined by indoor night capture of mosquitoes on human volunteers, revealing a calculated entomological inoculation rate of 34 infectious bites per person per year. Only Anopheles gambiae and A.

The N'-terminal domain of glyceraldehyde-3-phosphate dehydrogenase of the apicomplexan Plasmodium falciparum mediates GTPase Rab2-dependent recruitment to membranes.

Spatial and temporal distribution of the glycolytic enzymes glyceraldehyde-3-phosphate dehydrogenase (pfGAPDH) and aldolase (pfAldolase) of Plasmodium falciparum were investigated using specific mAbs and indirect immunofluorescence analysis (IFA). Both glycolytic enzymes were co-localized during ring and trophozoite stages of both liver and asexual blood stage parasites. During schizogony, pfGAPDH became associated with the periphery of the parasites and eventually accumulated in the apical region of merozoites, while pfAldolase showed no segregation.

In vitro activities of 25 quinolones and fluoroquinolones against liver and blood stage Plasmodium spp.

The in vitro activities of 25 quinolones and fluoroquinolones against erythrocytic stages of Plasmodium falciparum and against liver stages of Plasmodium yoelii yoelii and P. falciparum were studied. All compounds were inhibitory for chloroquine-sensitive and chloroquine-resistant P.

A glycosylphosphatidylinositol anchor signal sequence enhances the immunogenicity of a DNA vaccine encoding Plasmodium falciparum sexual-stage antigen, Pfs230.

Mammalian expression vectors encoding region C of malaria transmission-blocking vaccine candidate Pfs230 (aa 443-1132) with and without a 3' glycosylphosphatidylinositol (GPI) anchor signal sequence were tested for their immunogenicity in mice. The plasmid containing the GPI anchor signal sequence consistently induced higher titers of anti-Pfs230 antibodies using three delivery systems: intramuscular (i.m.

Hepatocyte CD81 is required for Plasmodium falciparum and Plasmodium yoelii sporozoite infectivity.

Plasmodium sporozoites are transmitted through the bite of infected mosquitoes and first invade the liver of the mammalian host, as an obligatory step of the life cycle of the malaria parasite. Within hepatocytes, Plasmodium sporozoites reside in a membrane-bound vacuole, where they differentiate into exoerythrocytic forms and merozoites that subsequently infect erythrocytes and cause the malaria disease. Plasmodium sporozoite targeting to the liver is mediated by the specific binding of major sporozoite surface proteins, the circumsporozoite protein and the thrombospondin-related anonymous protein, to glycosaminoglycans on the hepatocyte surface.

Analysis of the Plasmodium falciparum proteome by high-accuracy mass spectrometry.

The annotated genomes of organisms define a 'blueprint' of their possible gene products. Post-genome analyses attempt to confirm and modify the annotation and impose a sense of the spatial, temporal and developmental usage of genetic information by the organism. Here we describe a large-scale, high-accuracy (average deviation less than 0.

Laser capture microdissection of Plasmodium falciparum liver stages for mRNA analysis.

Plasmodium falciparum liver-stages are important targets for vaccine-induced protective immune responses and prophylactic treatment against malaria. Little is known of the gene expression profile of malaria parasites during their development inside hepatocytes. The sequencing of the P.