Project description:The purpose of this research is to identify and evaluate the global gene expression of the rodent malaria parasites Plasmodium yoelii, Plasmodium berghei and Plasmodium chabaudi blood-stage parasites and specifically compare the blood stage gene expression profiles of samples derived from previous studies on Plasmodium falciparum, Plasmodium vivax and Plasmodium knowlesi
Project description:Plasmodium yoelii YM asexual blood stage parasites express multiple members of the py235 gene family, part of the super-family of genes including those coding for Plasmodium vivax reticulocyte binding proteins and Plasmodium falciparum RH proteins. Dr Tony Holder's laboratory (NIMR, London) has been successful in deleting one of the RH family genes (Py01365) by transfection and insertion of the TgDHFR gene, and cloned the resulting parasite in YM background. The gene expression patterns of the mutant parasite line were compared to that of the wild type YM parasite.
Project description:Background: Malaria is a public health problem in parts of Thailand, where Plasmodium falciparum and Plasmodium vivax are the main causes of infection. In the northwestern border province of Tak parasite prevalence is now estimated to be less than 1% by microscopy. Nonetheless, microscopy is insensitive at low-level parasitaemia. The objective of this study was to assess the current epidemiology of falciparum and vivax malaria in Tak using molecular methods to detect exposure to and infection with parasites; in particular, the prevalence of asymptomatic infections and infections with submicroscopic parasite levels. Methods: Three-hundred microlitres of whole blood from finger-prick were collected into capillary tubes from residents of a sentinel village and from patients at a malaria clinic. Pelleted cellular fractions were screened by quantitative PCR to determine parasite prevalence, while plasma was probed on a protein microarray displaying hundreds of P. falciparum and P. vivax proteins to obtain antibody response profiles in those individuals. Results: Of 219 samples from the village, qPCR detected 25 (11.4%) Plasmodium sp. infections, of which 92% were asymptomatic and 100% were submicroscopic. Of 61 samples from the clinic patients, 27 (44.3%) were positive by qPCR, of which 25.9% had submicroscopic parasite levels. Cryptic mixed infections, misdiagnosed as single-species infections by microscopy, were found in 7 (25.9%) malaria patients. All sample donors, parasitaemic and non-parasitaemic alike, had serological evidence of parasite exposure, with 100% seropositivity to at least 54 antigens. Antigens significantly associated with asymptomatic infections were P. falciparum MSP2, DnaJ protein, putative E1E2 ATPase, and three others.
Project description:Plasmodium vivax causes 25-40% of malaria cases worldwide, yet research on this human malaria parasite has been neglected. Nevertheless, the recent publication of the P. vivax reference genome now allows genomics and systems biology approaches to be applied to this pathogen. We show here that whole genome analysis of the parasite can be achieved directly from ex vivo-isolated parasites, without the need for in vitro propagation. A single isolate of P. vivax obtained from a febrile patient with clinical malaria from Peru was subjected to whole genome sequencing (30X coverage). This analysis revealed over 18,261 single nucleotide polymorphisms (SNPs), 6,257 of which were further validated using a tiling microarray. Within core chromosomal genes we find that one SNP per every 985 bases of coding sequence distinguishes this recent Peruvian isolate, designated IQ07, from the reference Sal1 strain obtained in 1970. This full-genome sequence of a P. vivax isolate, the second overall and first of an uncultured patient isolate, shows that the same regions with low numbers of aligned sequencing reads are also highly variable by genomic microarray analysis. Finally, we show that the genes containing the largest ratio of nonsynonymous to synonymous SNPs encode two AP2 transcription factors and the P. vivax multidrug resistance-associated protein (PvMRP1), an ABC transporter shown to be associated with quinoline and antifolate tolerance in P. falciparum. This analysis provides a new data set for comparative analysis with important potential for identifying markers for global parasite diversity and drug resistance mapping studies. Genome DNA from Peruvian P. vivax Isolate IQ07 vs. Reference Sal1
Project description:Transcription profile of the Plasmodium vivax intraerythrocytic cycle Total RNA in Plasmodium vivax strain at every 6 hour of intraerythrocytic cycle using RNA-seq
Project description:The complete genome sequence of the P. vivax Sal-1 strain allowed the design of a first version array representing 1 oligo/2 kb of coding sequences (http://zblab.sbs.ntu.edu.sg/vivax/index.html). Here, proof-of-principle experiments using total RNA of parasites obtained from the Sal-1 strain, from P. falciparum and from parasites obtained directly from two human patients are presented. To determine the extent of cross-hybridization of P. falciparum with P. vivax, and to determine overlaps in expression profiles of the P. vivax Sal1 monkey-adapted strain vs wild isolates, single dual hybridization analyses were performed.
Project description:Heterochromatin is a tightly packaged form of DNA that leads to permanent or temporal gene silencing. In P. falciparum heterochromatin is formed after trimethylation of lysine 9 on histone H3 and consequent binding of heterochromatin protein 1 (HP1). Genome-wide profiling studies established that in P. falciparum blood stage schizonts heterochromatin is formed at subtelomeres and some intra-chromosomal islands. Reversible silencing of genes located in these regions has been shown to be key to, among others, antigenic variation, invasion pathway selection or commitment to gametocytogenesis. However, heterochromatic gene silencing has not been investigated in many other Plasmodium species, strains or life cycle stages, yet. Here, we used ChIP-seq to profile HP1 occupancy in asexual parasites of six different species (P. falciparum, P. knowlesi, P. vivax, P. berghei, P. yoelii, and P. chabaudi) and of four different P. falciparum strains (3D7, PF2004, NF54, NF135) as well as two different P. knowlesi clones (A1C1, A1H1). Additionally, we performed HP1 ChIP-seq on three asexual stages (ring, trophozoite and schizont stage) and two sexual stages of P. falciparum parasites. Collectively, the generated HP1 profiles provide a detailed catalog of heterochromatic genes and reveal conserved and specialized features of epigenetic control at different life cycle stages, strains and species across the genus Plasmodium.
Project description:Malaria morbidity and mortality caused by both Plasmodium falciparum and Plasmodium vivax extend well beyond the African continent, and, although P. vivax causes 80-300 million severe cases each year, vivax transmission remains poorly understood. Plasmodium parasites are transmitted by Anopheles mosquitoes, and the critical site of interaction between parasite and host is at the mosquito's luminal midgut brush border. While the genome of the "model" African P. falciparum vector, Anopheles gambiae, has been sequenced, evolutionary divergence limits its utility as a reference across anophelines, especially non-sequenced P. vivax vectors such as Anopheles albimanus. Clearly, enabling technologies and platforms that bridge this substantial scientific gap are required in order to provide public health scientists key transcriptomic and proteomic information that could spur the development of novel interventions to combat this disease. To our knowledge, no approaches have been published which address this issue. To bolster our understanding of P. vivax-An. albimanus midgut interactions, we developed an integrated bioinformatic-hybrid RNA-Seq-LC-MS/MS approach involving An. albimanus transcriptome (15,764 contigs) and luminal midgut subproteome (9,445 proteins) assembly, which, when used with our custom Diptera protein database (685,078 sequences), facilitated a comparative proteomic analysis of the midgut brush borders of two important malaria vectors, An. gambiae and An. albimanus. Summary from: http://www.mcponline.org/content/early/2012/10/17/mcp.M112.019596.long The An. albimanus transcriptome dataset is available at http://funcgen.vectorbase.org/RNAseq/Anopheles_albimanus/INSP/v2
Project description:ChIP-seq experiments were performed for the putative telomere repeat-binding factor (PfTRF) in the malaria parasite Plasmodium falciparum strain 3D7. The gene encoding this factor (PF3D7_1209300) was endogenously tagged with either a GFP- or a 3xHA-tag and these transgenic parasite lines were used in ChIP-sequencing experiments. Sequencing of the ChIP and input libraries showed enrichment of PfTRF at all telomere-repeat containing chromosome ends (reference genome Plasmodium falciparum 3D7 from PlasmoDB version 6.1) as well as in all upsB var promoters.In addition,PfTRF was enriched at seven additional, intra-chromosomal sites and called in the PfTRF-HA ChIP-seq only. Plasmodium falciparum 3D7 parasites were generated with -GFP or -3xHA C-terminal tagged TRF (PF3D7_1209300). Nuclei were isolated from formaldehyde cross-linked schizont-stage transgenic parasites and used to prepare chromatin. Chromatin immunoprecipitations were performed using mouse anti-GFP (Roche Diagnostics, #11814460001) or rat anti-HA 3F10 (Roche Diagnostics, #12158167001). Sequencing libraries were prepared according to a Plasmodium-optimized library preparation procedure including KAPA polymerase-mediated PCR amplification.
Project description:Plasmodium vivax causes 25-40% of malaria cases worldwide, yet research on this human malaria parasite has been neglected. Nevertheless, the recent publication of the P. vivax reference genome now allows genomics and systems biology approaches to be applied to this pathogen. We show here that whole genome analysis of the parasite can be achieved directly from ex vivo-isolated parasites, without the need for in vitro propagation. A single isolate of P. vivax obtained from a febrile patient with clinical malaria from Peru was subjected to whole genome sequencing (30X coverage). This analysis revealed over 18,261 single nucleotide polymorphisms (SNPs), 6,257 of which were further validated using a tiling microarray. Within core chromosomal genes we find that one SNP per every 985 bases of coding sequence distinguishes this recent Peruvian isolate, designated IQ07, from the reference Sal1 strain obtained in 1970. This full-genome sequence of a P. vivax isolate, the second overall and first of an uncultured patient isolate, shows that the same regions with low numbers of aligned sequencing reads are also highly variable by genomic microarray analysis. Finally, we show that the genes containing the largest ratio of nonsynonymous to synonymous SNPs encode two AP2 transcription factors and the P. vivax multidrug resistance-associated protein (PvMRP1), an ABC transporter shown to be associated with quinoline and antifolate tolerance in P. falciparum. This analysis provides a new data set for comparative analysis with important potential for identifying markers for global parasite diversity and drug resistance mapping studies.