Scanning Electron Microscopy of Gregarines (Protozoa, Sporozoa) and Its Contribution to the Theory of Gregarine Movement

Vávra, Jiří; Small, Eugene B.

doi:10.1111/j.1550-7408.1969.tb02338.x

Cited by 44 publications

(33 citation statements)

References 10 publications

(10 reference statements)

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“…We also find that in IEM following reactivity with PfCEN2 antibodies, gold particles were observed in areas on or around rhoptries (data not shown). It has been postulated that the ancestors of modern apicomplexans adapted to their obligate intracellular parasitic lifestyle in multiple ways, including the loss of flagella (except in male gametes) (62,63) and development of a closed conoid. The phylogenetic and morphological data points to its origin from an open-sided conoid as seen in colpodellids and perkinsids (64).…”

Section: Glp_158_56914_57444 (29250378)mentioning

confidence: 99%

Centrins, Cell Cycle Regulation Proteins in Human Malaria Parasite Plasmodium falciparum

Mahajan

Selvapandiyan

Gerald

et al. 2008

Journal of Biological Chemistry

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Molecules and cellular mechanisms that regulate the process of cell division in malaria parasites remain poorly understood. In this study we isolate and characterize the four Plasmodium falciparum centrins (PfCENs) and, by growth complementation studies, provide evidence for their involvement in cell division. Centrins are cytoskeleton proteins with key roles in cell division, including centrosome duplication, and possess four Ca 2؉ -binding EF hand domains. By means of phylogenetic analysis, we were able to decipher the evolutionary history of centrins in eukaryotes with particular emphasis on the situation in apicomplexans and other alveolates. Plasmodium possesses orthologs of four distinct centrin paralogs traceable to the ancestral alveolate, including two that are unique to alveolates. By real time PCR and/or immunofluorescence, we determined the expression of PfCEN mRNA or protein in sporozoites, asexual blood forms, gametocytes, and in the oocysts developing inside mosquito mid-gut. Immunoelectron microscopy studies showed that centrin is expressed in close proximity with the nucleus of sporozoites and asexual schizonts. Furthermore, confocal and widefield microscopy using the double staining with ␣-tubulin and centrin antibodies strongly suggested that centrin is associated with the parasite centrosome. Following the episomal expression of the four PfCENs in a centrin knock-out Leishmania donovani parasite line that exhibited a severe growth defect, one of the PfCENs was able to partially restore Leishmania growth rate and overcome the defect in cytokinesis in such mutant cell line. To our knowledge, this study is the first characterization of a Plasmodium molecule that is involved in the process of cell division. These results provide the opportunity to further explore the role of centrins in cell division in malaria parasites and suggest novel targets to construct genetically modified, live attenuated malaria vaccines.

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Section: Glp_158_56914_57444 (29250378)mentioning

confidence: 99%

Centrins, Cell Cycle Regulation Proteins in Human Malaria Parasite Plasmodium falciparum

Mahajan

Selvapandiyan

Gerald

et al. 2008

Journal of Biological Chemistry

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“…The ancestors of modern apicomplexans adapted to their obligate intracellular parasitic lifestyle in several ways, including the loss of flagella (except in some microgametes) and the development of gliding motility [38,39]. Perhaps the most notable innovations of apicomplexans are complex life cycles comprising a cell-invasion stage (sporozoite) with a well conserved, closed conoid.…”

Section: The First Apicomplexansmentioning

confidence: 99%

Morphostasis in alveolate evolution

Leander

Keeling

2003

Trends in Ecology & Evolution

149

131

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“…We were able to show the surface knobs of L. ascidiae by SEM revealing a dense array of the knobs. Epicytic folds are also known to play an important role in gliding motility (Vávra & Small 1969, Heintzelman 2004. As already seen in L. chelyosomae and L. cystodytae (Rueckert & Leander 2008), L. ascidiae is capable of gliding motility (Movie 1 in the supplement), even though all these lack a continuous coverage of epicytic folds.…”

Section: Lankesteria Ascidiaementioning

confidence: 77%

“…The digested materials of the diseased animals are sticky and they maintain the thin tubular structure after they are transferred to the intestine. Gregarines are known to produce mucus (Vávra & Small 1969), which might make the feces sticky. The intestines of diseased animals are also occupied by many gregarines, restricting the space of the digestive tube for excretion, which is another cause of long feces and the congestion of the digestive tube with digested material.…”

Section: Long Feces Syndromementioning

confidence: 99%

Large-scale infection of the ascidian Ciona intestinalis by the gregarine Lankesteria ascidiae in an inland culture system

Mita¹,

Kawai²,

Rueckert³

et al. 2012

Dis. Aquat. Org.

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An important way to keep transgenic and mutant lines of the ascidian Ciona intestinalis, a model system for e.g. genetic functions, in laboratories is via culturing systems. Here we report a disease of C. intestinalis observed in an inland culturing system. The disease, called 'long feces syndrome,' is expressed in affected animals by the following characteristic symptoms of the digestive system: (1) excretion of long and thin feces, (2) pale color of the stomach, and (3) congestion of the digestive tube by digested material. Severely diseased animals usually die within a week after the first symptoms occur, implying a high risk of this disease for ascidian culturing systems. The digestive tubes of the diseased animals are occupied by the gregarine apicomplexan parasite Lankesteria ascidiae, suggesting that large-scale infection by this parasite is the cause of long feces syndrome.

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Scanning Electron Microscopy of Gregarines (Protozoa, Sporozoa) and Its Contribution to the Theory of Gregarine Movement

Cited by 44 publications

References 10 publications

Centrins, Cell Cycle Regulation Proteins in Human Malaria Parasite Plasmodium falciparum

Centrins, Cell Cycle Regulation Proteins in Human Malaria Parasite Plasmodium falciparum

Morphostasis in alveolate evolution

Large-scale infection of the ascidian Ciona intestinalis by the gregarine Lankesteria ascidiae in an inland culture system

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