3‐D analysis of the <i>Plasmodium falciparum</i> Maurer's clefts using different electron tomographic approaches

Henrich, Philipp P.; Kilian, Nicole; Lanzer, Michael; Cyrklaff, Marek

doi:10.1002/biot.200900058

Cited by 26 publications

(17 citation statements)

References 27 publications

(43 reference statements)

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“…In this work, we used electron tomography to study the digestive apparatus. Electron tomography permits analysis of 300-400 nm sections with enhanced z-plane resolution and has been used to identify novel features of the P. falciparum exomembrane system Henrich et al, 2009). We implemented methods for collecting data from multiple sections and used programs for tiling and stitching tomographic data (Hanssen et al, 2009;Noske et al, 2008) to generate whole parasite images; this allowed us to re-examine the 3D ultrastructure of the digestive apparatus at different stages of parasite development.…”

Section: Haemoglobin Uptake and Degradation Is Initiated In Early Stamentioning

confidence: 99%

Digestive-vacuole genesis and endocytic processes in the early intraerythrocytic stages of Plasmodium falciparum

Bakar

Klonis

Hanssen

et al. 2010

Journal of Cell Science

170

209

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SummaryThe digestive vacuole of the malaria parasite Plasmodium falciparum is the site of haemoglobin digestion and haem detoxification, and is the target of chloroquine and other antimalarials. The mechanisms for genesis of the digestive vacuole and transfer of haemoglobin from the host cytoplasm are still debated. Here, we use live-cell imaging and photobleaching to monitor the uptake of the pH-sensitive fluorescent tracer SNARF-1-dextran from the erythrocyte cytoplasm in ring-stage and trophozoite-stage parasites. We compare these results with electron tomography of serial sections of parasites at different stages of growth. We show that uptake of erythrocyte cytoplasm is initiated in mid-ring-stage parasites. The host cytoplasm is internalised via cytostome-derived invaginations and concentrated into several acidified peripheral structures. Haemoglobin digestion and haemozoin formation take place in these vesicles. The ringstage parasites can adopt a deeply invaginated cup shape but do not take up haemoglobin via macropinocytosis. As the parasite matures, the haemozoin-containing compartments coalesce to form a single acidic digestive vacuole that is fed by haemoglobin-containing vesicles. There is also evidence for haemoglobin degradation in compartments outside the digestive vacuole. The work has implications for the stage specificity of quinoline and endoperoxide antimalarials.

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Section: Haemoglobin Uptake and Degradation Is Initiated In Early Stamentioning

confidence: 99%

Digestive-vacuole genesis and endocytic processes in the early intraerythrocytic stages of Plasmodium falciparum

Bakar

Klonis

Hanssen

et al. 2010

Journal of Cell Science

170

209

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“…Cryo-electron tomography is widely regarded to introduce the fewest artefacts during preparation as the specimen is rapidly frozen (within a few milliseconds) thus preserving molecular details and membrane arrangements [19,20]. This technique has been used successfully to investigate membranous and cytoskeletal structures in sporozoites of P. berghei [15,21-23] and Maurer’s clefts of P. falciparum infected red blood cells [24,25]. Cryo-electron tomography does not include staining with heavy metal salts and thus provides lower contrast, though being sufficient to examine membranes [26].…”

Section: Introductionmentioning

confidence: 99%

Cryo-electron tomography reveals four-membrane architecture of the Plasmodium apicoplast

Lemgruber

Kudryashev

Dekiwadia

et al. 2013

Malar J

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BackgroundThe apicoplast is a plastid organelle derived from a secondary endosymbiosis, containing biosynthetic pathways essential for the survival of apicomplexan parasites. The Toxoplasma apicoplast clearly possesses four membranes but in related Plasmodium spp. the apicoplast has variably been reported to have either three or four membranes.MethodsCryo-electron tomography was employed to image merozoites of Plasmodium falciparum and Plasmodium berghei frozen in their near-native state. Three-dimensional reconstructions revealed the number of apicoplast membranes and the association of the apicoplast with other organelles. Routine transmission electron microscopy of parasites preserved by high-pressure freezing followed by freeze substitution techniques was also used to analyse apicoplast morphology.ResultsCryo-preserved parasites showed clearly four membranes surrounding the apicoplast. A wider gap between the second and third apicoplast membranes was frequently observed. The apicoplast was found in close proximity to the nucleus and to the rhoptries. The apicoplast matrix showed ribosome-sized particles and membranous whorls.ConclusionsThe Plasmodium apicoplast possesses four membranes, as do the apicoplasts of other apicomplexan parasites. This is consistent with a four-membraned secondary endosymbiotic plastid ancestor.

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“…To circumvent this problem, cryo-electron microscopy of vitrified sections (CEMOVIS) could be applied, which allows tomography of rapidly frozen and cryo-sectioned samples [55,56]. Alternatively, merozoites could be imaged in the process of invading an erythrocyte ghost [57,58]. However, even if actin filaments would be revealed, it would still be interesting to image actin filaments during sporozoite gliding as filaments might well be differently arranged during motility and host cell invasion.…”

Section: Discussionmentioning

confidence: 99%

Geometric constrains for detecting short actin filaments by cryogenic electron tomography

et al. 2010

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Polymerization of actin into filaments can push membranes forming extensions like filopodia or lamellipodia, which are important during processes such as cell motility and phagocytosis. Similarly, small organelles or pathogens can be moved by actin polymerization. Such actin filaments can be arranged in different patterns and are usually hundreds of nanometers in length as revealed by various electron microscopy approaches. Much shorter actin filaments are involved in the motility of apicomplexan parasites. However, these short filaments have to date not been visualized in intact cells. Here, we investigated Plasmodium sporozoites, the motile forms of the malaria parasite that are transmitted by the mosquito, using cryogenic electron tomography. We detected filopodia-like extensions of the plasma membrane and observed filamentous structures in the supra-alveolar space underneath the plasma membrane. However, these filaments could not be unambiguously assigned as actin filaments. In silico simulations of EM data collection and tomographic reconstruction identify the limits in revealing the filaments due to their length, concentration and orientation.PACS Codes: 87.64.Ee

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3‐D analysis of the Plasmodium falciparum Maurer's clefts using different electron tomographic approaches

Cited by 26 publications

References 27 publications

Digestive-vacuole genesis and endocytic processes in the early intraerythrocytic stages of Plasmodium falciparum

Digestive-vacuole genesis and endocytic processes in the early intraerythrocytic stages of Plasmodium falciparum

Cryo-electron tomography reveals four-membrane architecture of the Plasmodium apicoplast

Geometric constrains for detecting short actin filaments by cryogenic electron tomography

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