Project description:Plasmodium vivax causes the most geographically widespread human malaria, accounting annually for 70-80 million clinical cases throughout the tropical and subtropical regions of the world's continents. We have analyzed the DNA sequences of the Csp (circumsporozoite protein) gene in 24 geographically representative strains of P. vivax and 2 of P. simium, which parasitizes several species of New World monkeys. The Csp sequences are of two types, VK210 and VK247, which differ by three diagnostic amino acid replacements, one in each of the 5' and 3' terminal regions [5' nonrepeat (NR) and 3' NR] of the gene and in an insertion sequence that precedes the 3' NR region. The central region of the gene consists of approximately 38 repetitive "motifs," which are alternatively four and five amino acids long, which also are diagnostically different between the VK210 and VK247 types. There are very few synonymous substitutions within and between the two types of strains, which we hypothesize reflects that the worldwide spread of P. vivax is very recent. The two P. simium Csp sequences belong one to each of the two VK types and are genetically indistinguishable from the corresponding P. vivax strains, suggesting that at least two host transfers have occurred between humans and New World monkeys. We exclude as unlikely the possibility that the two types of sequences could have independently arisen in humans and platyrrhines by natural selection. There are reasons favoring each of the two possible directions of host transfer between humans and monkeys.
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:Genome-wide ChIP-sequencing analysis of PfMCM6 was carried out in trophozoite stage parasites using PfMCM6 antibodies. We have observed that PfMCM6 is highly enriched at the exon regions. Moreover, PfMCM6 was also found in promoter-TSS, transcription termination site (TTS), and intergenic regions in minimal proportion. This study shed some light on PfMCM6 binding sites in Plasmodium falciparum genome.
Project description:Genome-wide ChIP-sequencing analysis of PfGCN5 was carried out in asynchronous stage (trophozoite and schizont stage enriched) parasites using PfGCN5 antibodies. We have observed that PfGCN5 is majorly associated with promoter regions of genes. Moreover, a uniform distribution was found in exons, transcription termination site, and intergenic regions. This study shed some light on PfGCN5 binding sites on Plasmodium falciparum genome.
Project description:BackgroundThe population history of Plasmodium simium, which causes malaria in sylvatic Neotropical monkeys and humans along the Atlantic Coast of Brazil, remains disputed. Genetically diverse P vivax populations from various sources, including the lineages that founded the species P simium, are thought to have arrived in the Americas in separate migratory waves.MethodsWe use population genomic approaches to investigate the origin and evolution of P simium.ResultsWe find a minimal genome-level differentiation between P simium and present-day New World P vivax isolates, consistent with their common geographic origin and subsequent divergence on this continent. The meagre genetic diversity in P simium samples from humans and monkeys implies a recent transfer from humans to non-human primates - a unique example of malaria as a reverse zoonosis of public health significance. Likely genomic signatures of P simium adaptation to new hosts include the deletion of >40% of a key erythrocyte invasion ligand, PvRBP2a, which may have favored more efficient simian host cell infection.ConclusionsNew World P vivax lineages that switched from humans to platyrrhine monkeys founded the P simium population that infects nonhuman primates and feeds sustained human malaria transmission in the outskirts of major cities.
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