Comparative 3D ultrastructure of Plasmodium falciparum gametocytes
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ABSTRACT:
SUBMITTER: Taco W.A. Kooij
PROVIDER: EMPIAR-12160 | biostudies-other |
REPOSITORIES: biostudies-other
Similar Datasets
Project description:The sexual stages are vital phases in malaria parasite transmission and are the targets of various interventions such as transmission blocking vaccines. The molecular mechanisms underlying sexual development, however, remain poorly understood. We report mappping of a determinant previously linked to a male gametocyte development defect in the P. falciparum Dd2 parasite to an 82 kb region on chromosome 12. In order to find a critical gene in this region, we compared gene expression pattern in sexual stage of the parasite between Dd2 and its normal gametocyte-producing ancestor W2 clones. The region contains a sexual stage specific gene (pfmdv 1) that is expressed substantially at a lower level in the Dd2 than in W2 parasite. Disruption of pfmdv 1 results in a dramatic reduction in mature gametocytes, especially male gametocytes, with the majority of sexually committed parasites arrested at stage-I. The pfmdv-1 knockout parasites show an enlarged nucleus, often with separation of the inner and outer nuclear membranes and presence of multi-membrane vesicles in red blood cell cytoplasm. Mosquito infectivity of the knockout parasites is also greatly reduced, but not completely lost, suggesting presence of compensatory mechanisms in the sexual development pathways. Data include Day 8 gametocytes of male defective Dd2 and parental W2 clones of Plasmodium falciparum. The series includes three biological repeats. Keywords: repeat sample
2010-06-10 | E-GEOD-2265 | biostudies-arrayexpress
Project description:BackgroundThe sexual stages (gametocytes) of Plasmodium falciparum do not directly contribute to the pathology of malaria but are essential for transmission of the parasite from the human host to the mosquito. Mature gametocytes circulate in infected human blood for several days and their circulation time has been modelled mathematically from data of previous in vivo studies. This is the first time that longevity of gametocytes is studied experimentally in vitro.MethodsThe in vitro longevity of P. falciparum gametocytes of 1 clinical isolate and 2 laboratory strains was assessed by three different methods: microscopy, flow cytometry and reverse transcription quantitative real-time PCR (RT-qPCR). Additionally, the rate of gametocytogenesis of the used P. falciparum strains was compared.ResultsThe maximum in vitro lifespan of P. falciparum gametocytes reached almost 2 months (49 days by flow cytometry, 46 days by microscopy, and at least 52 days by RT-qPCR) from the starting day of gametocyte culture to death of last parasite in the tested strains with an average 50% survival rate of 6.5, 2.6 and 3.5 days, respectively. Peak gametocytaemia was observed on average 19 days after initiation of gametocyte culture followed by a steady decline due to natural decay of the parasites. The rate of gametocytogenesis was highest in the NF54 strain.ConclusionsPlasmodium falciparum mature gametocytes can survive up to 16-32 days (at least 14 days for mature male gametocytes) in vitro in absence of the influence of host factors. This confirms experimentally a previous modelling estimate that used molecular tools for gametocyte detection in treated patients. The survival time might reflect the time the parasite can be transmitted to the mosquito after clearance of asexual parasites. These results underline the importance of efficient transmission blocking agents in the fight against malaria.
| S-EPMC5553604 | biostudies-literature
Project description:Plasmodium falciparum gametocytes have unique morphology, metabolism, and protein expression profiles in their asexual stages of development. In addition to the striking changes in their appearance, a wide variety of "exo-membrane structures" are newly formed in the gametocyte stage. Little is known about their function, localization, or three-dimensional structural information, and only some structural data, typically two-dimensional, have been reported using conventional electron microscopy or fluorescence microscopy. For better visualization of intracellular organelle and exo-membrane structures, we previously established an unroofing technique to directly observe Maurer's clefts (MCs) in asexual parasitized erythrocytes by removing the top part of the cell's membrane followed by transmission electron microscopy. We found that MCs have numerous tethers connecting themselves to the host erythrocyte membrane skeletons. In this study, we investigated the intracellular structures of gametocytes using unroofing-TEM, Serial Block Face scanning electron microscopy, and fluorescence microscopy to unveil the exo-membrane structures in gametocytes. Our data showed "balloon/pouch"-like objects budding from the parasitophorous vacuole membrane (PVM) in gametocytes, and some balloons included multiple layers of other balloons. Furthermore, numerous bubbles appeared on the inner surface of the erythrocyte membrane or PVM; these were similar to MC-like membranes but were smaller than asexual MCs. Our study demonstrated P. falciparum reforms exo-membranes in erythrocytes to meet stage-specific biological activities during their sexual development.
| S-EPMC9441640 | biostudies-literature
Project description:The sexual stages are vital phases in malaria parasite transmission and are the targets of various interventions such as transmission blocking vaccines. The molecular mechanisms underlying sexual development, however, remain poorly understood. We report mappping of a determinant previously linked to a male gametocyte development defect in the P. falciparum Dd2 parasite to an 82 kb region on chromosome 12. In order to find a critical gene in this region, we compared gene expression pattern in sexual stage of the parasite between Dd2 and its normal gametocyte-producing ancestor W2 clones. The region contains a sexual stage specific gene (pfmdv 1) that is expressed substantially at a lower level in the Dd2 than in W2 parasite. Disruption of pfmdv 1 results in a dramatic reduction in mature gametocytes, especially male gametocytes, with the majority of sexually committed parasites arrested at stage-I. The pfmdv-1 knockout parasites show an enlarged nucleus, often with separation of the inner and outer nuclear membranes and presence of multi-membrane vesicles in red blood cell cytoplasm. Mosquito infectivity of the knockout parasites is also greatly reduced, but not completely lost, suggesting presence of compensatory mechanisms in the sexual development pathways. Data include Day 8 gametocytes of male defective Dd2 and parental W2 clones of Plasmodium falciparum. The series includes three biological repeats. Keywords: repeat sample
2005-05-01 | GSE2265 | GEO
Project description: Not available
| EMPIAR-10392 | biostudies-other
Project description:The recent decline in global malaria burden has stimulated efforts toward Plasmodium falciparum elimination. Understanding the biology of malaria transmission stages may provide opportunities to reduce or prevent onward transmission to mosquitoes. Immature P. falciparum transmission stages, termed stages I to IV gametocytes, sequester in human bone marrow before release into the circulation as mature stage V gametocytes. This process likely involves interactions between host receptors and potentially immunogenic adhesins on the infected red blood cell (iRBC) surface. Here, we developed a flow cytometry assay to examine immune recognition of live gametocytes of different developmental stages by naturally exposed Malawians. We identified strong antibody recognition of the earliest immature gametocyte-iRBCs (giRBCs) but not mature stage V giRBCs. Candidate surface antigens (n = 30), most of them shared between asexual- and gametocyte-iRBCs, were identified by mass spectrometry and mouse immunizations, as well as correlations between responses by protein microarray and flow cytometry. Naturally acquired responses to a subset of candidate antigens were associated with reduced asexual and gametocyte density, and plasma samples from malaria-infected individuals were able to induce immune clearance of giRBCs in vitro. Infected RBC surface expression of select candidate antigens was validated using specific antibodies, and genetic analysis revealed a subset with minimal variation across strains. Our data demonstrate that humoral immune responses to immature giRBCs and shared iRBC antigens are naturally acquired after malaria exposure. These humoral immune responses may have consequences for malaria transmission potential by clearing developing gametocytes, which could be leveraged for malaria intervention.
| S-EPMC6653583 | biostudies-literature
Project description:New techniques for obtaining electron microscopy data through the cell volume are being increasingly utilized to answer cell biologic questions. Here, we present a three-dimensional atlas of Plasmodium falciparum ultrastructure throughout parasite cell division. Multiple wild type schizonts at different stages of segmentation, or budding, were imaged and rendered, and the 3D structure of their organelles and daughter cells are shown. Our high-resolution volume electron microscopy both confirms previously described features in 3D and adds new layers to our understanding of Plasmodium nuclear division. Interestingly, we demonstrate asynchrony of the final nuclear division, a process that had previously been reported as synchronous. Use of volume electron microscopy techniques for biological imaging is gaining prominence, and there is much we can learn from applying them to answer questions about Plasmodium cell biology. We provide this resource to encourage readers to consider adding these techniques to their cell biology toolbox.
| S-EPMC7302870 | biostudies-literature
Project description:The gametocyte transcriptomes were generated in P.falciparum parasites of 3D7 strain after PfHP1 depletion aming to determin the transriptional profiles of sexual stages during the parasites gametocyte development.
2018-12-10 | GSE121505 | GEO
Project description:Investigation of whole genome gene expression level in Plasmodium falciparum male and female mature gametocytes, and detection of any transcriptional differences between male and female gametocytes. The Plasmodium falciparum parasite with green fluorescent protein (GFP) expression under the control of alpha tubulin II promoter facilitated the separation of male and female gametocyte. This engineered parasite strain in this study are further described in Miao J, Fan Q, Parker D, Li X, Li J, et al. (2013) Puf Mediates Translation Repression of Transmission-Blocking Vaccine Candidates in Malaria Parasites. PLoS Pathog 9(4): e1003268. doi: 10.1371/journal.ppat.1003268
2016-01-28 | GSE77316 | GEO
Project description:BackgroundAccurate sampling of sub-microscopic gametocytes is necessary for epidemiological studies to identify the infectious reservoir of Plasmodium falciparum. Detection of gametocyte mRNA achieves sensitive detection, but requires careful handling of samples. Filter papers can be used for collecting RNA samples, but rigorous testing of their capacity to withstand adverse storage conditions has not been fully explored.MethodsThree gametocyte dilutions: 10/?L, 1.0/?L and 0.1/?L were spotted onto Whatman™ 903 Protein Saver Cards, FTA Classic Cards and 3MM filter papers that were stored under frozen, cold chain or tropical conditions for up to 13 weeks . RNA was extracted, then detected by quantitative nucleic acid sequence-based amplification (QT-NASBA) and reverse-transcriptase PCR (RT-PCR).ResultsSuccessful gametocyte detection was more frequently observed from the Whatman 903 Protein Saver Card compared to the Whatman FTA Classic Card, by both techniques (p<0.0001). When papers were stored at higher temperatures, a loss in sensitivity was experienced for the FTA Classic Card but not the 903 Protein Saver Card or Whatman 3MM filter paper. The sensitivity of gametocyte detection was decreased when papers were stored at high humidity.ConclusionsThis study indicates the Whatman 903 Protein Saver Card is better for Pfs25 mRNA sampling compared to the Whatman FTA Classic Card, and that the Whatman 3MM filter paper may prove to be a satisfactory cheaper option for Pfs25 mRNA sampling. When appropriately dried, filter papers provide a useful approach to Pfs25 mRNA sampling, especially in settings where storage in RNA-protecting buffer is not possible.
| S-EPMC3441243 | biostudies-literature