Bewegungsphysiologische Untersuchungen an polycystiden Gregarinen unter Anwendung des Mikrozeitrafferfilmes

Richter, I. E.

doi:10.1007/bf01252489

Cited by 12 publications

(5 citation statements)

References 7 publications

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“…Two systems of myonemes, one longitudinal, one circular, have been recognized in a number of gregarines (22). Localized contractions of these myonemes on the side where the gregarine touches the substratum were said to cause a slight undulatory motion of the pellicle which in turn pushed the organism forward (4, 5, 11, 18, 21,34,36).…”

Section: Groupsmentioning

confidence: 99%

“…In Pileocephalus this free edge is thicker and more oval than in the 2 Gregarina species from Tenebrio (Figs. 5, 6,20,21 ) . The shape of the folds can be well observed at the edge of accidentally broken specimens ( Fig.…”

Section: Observationsmentioning

confidence: 99%

“…Most of the folds in each individual are about the same size, altho occasionally there may be lower ones (Figs. 5,21). The folds may differ in height in different specimens of the same species.…”

Section: Observationsmentioning

confidence: 99%

See 2 more Smart Citations

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

Vávra

Small

1969

The Journal of Protozoology

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SYNOPSIS. Scanning electron microscopy was used to reveal detailed surface structure of 4 septate (Gregarina cuneata, G. steini, G. rhyparobiae, Pileocephalus blaberae) and one aseptate species (Nematocystis elmassiani) of eugregarines. The epicyte of all these gregarines is differentiated into a system of regular longitudinal folds. In the septate species these folds undulate so that these organisms glide along. The undulatory pattern is absent from Nematocystis, which does not glide. The theories and the mechanism of gregarine gliding are discussed.

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Section: Groupsmentioning

confidence: 99%

Section: Observationsmentioning

confidence: 99%

See 1 more Smart Citation

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

Vávra

Small

1969

The Journal of Protozoology

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“…Recent analyses, however, indicate a close affinity of gregarines with species of Cryptosporidium [ 7 , 8 ] that parasitize humans. Most eugregarine gamonts are covered by a pellicle folded in numerous longitudinal epicytic folds (e.g., Gregarina , Lecudina ) [ 9 - 11 ] and exhibit gliding motility [ 12 - 14 ]. Using a laser trap and bead translocation, King and Sleep [ 15 ] have described gliding as an irregular, erratic process.…”

Section: Introductionmentioning

confidence: 99%

The enigma of eugregarine epicytic folds: where gliding motility originates?

et al. 2013

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BackgroundIn the past decades, many studies focused on the cell motility of apicomplexan invasive stages as they represent a potential target for chemotherapeutic intervention. Gregarines (Conoidasida, Gregarinasina) are a heterogeneous group that parasitize invertebrates and urochordates, and are thought to be an early branching lineage of Apicomplexa. As characteristic of apicomplexan zoites, gregarines are covered by a complicated pellicle, consisting of the plasma membrane and the closely apposed inner membrane complex, which is associated with a number of cytoskeletal elements. The cell cortex of eugregarines, the epicyte, is more complicated than that of other apicomplexans, as it forms various superficial structures.ResultsThe epicyte of the eugregarines, Gregarina cuneata, G. polymorpha and G. steini, analysed in the present study is organised in longitudinal folds covering the entire cell. In mature trophozoites and gamonts, each epicytic fold exhibits similar ectoplasmic structures and is built up from the plasma membrane, inner membrane complex, 12-nm filaments, rippled dense structures and basal lamina. In addition, rib-like myonemes and an ectoplasmic network are frequently observed. Under experimental conditions, eugregarines showed varied speeds and paths of simple linear gliding. In all three species, actin and myosin were associated with the pellicle, and this actomyosin complex appeared to be restricted to the lateral parts of the epicytic folds. Treatment of living gamonts with jasplakinolide and cytochalasin D confirmed that actin actively participates in gregarine gliding. Contributions to gliding of specific subcellular components are discussed.ConclusionsCell motility in gregarines and other apicomplexans share features in common, i.e. a three-layered pellicle, an actomyosin complex, and the polymerisation of actin during gliding. Although the general architecture and supramolecular organisation of the pellicle is not correlated with gliding rates of eugregarines, an increase in cytoplasmic mucus concentration is correlated. Furthermore, our data suggest that gregarines utilize several mechanisms of cell motility and that this is influenced by environmental conditions.

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“…De tels mouvements ondulatoires des plis sont 8 la limite de visibilitk du microscope optique et c'est pourquoi ils ont pu gCnCralement passCs inapercu ; cependant l'observation in vivo en contraste de phase ou en contraste interfkrentiel, montre bien, chez Lecudina, la prksence d'ondulations des plis sans toutefois que l'on puisse saiser les details du phknomhe. Quelques auteurs d'ailleurs, les ont pressentis et signalks; c'est ainsi que Richter(29) signale des modifi-cations ondulatoires de la pellicule, mais sans faire la relation avec la locomotion. Mais il est curieux de noter que ces observations au microscope Clectronique se superposent avec certaines figures de Roskin et Levinson(30): en particulier la Fig.…”

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L'Organisation Ultrastructurale Corticale de la Gregarine Lecudina pellucida; ses Rapports avec l'Alimentation et la Locomotion

Vivier

1968

The Journal of Protozoology

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SYNOPSIS. The structure of the cortical region (epicyte and ectoplasm) of the gregarine Lecudina pellucida, an intestinal parasite of the polychete worm Perinereis cultrifera was studied by electron microscopy. The epicitary folds have 3 unit type membranes. Between the 1st and 2nd is a layer probably composed of fine longitudinal fibrils which has an arch‐like or gutter‐like structure at the crest of the folds. Inside these folds is cytoplasm without any noticeable differentiation or inclusion except for a granular (or finely fibrillar) layer under the limiting inner membrane and close to it. The ectoplasmic zone of the entocyte is separated from the epicitary region by a lengthwise discontinuous cylindrical opaque layer, inwardly tangential to the folds. The ectoplasm lacks paraglycogen granules but has various organelles: apparently pinocytic vesicles against the wall between the folds, vesicles with myelinic membranes, opaque granules, a few mitochondria with blistered internal vesicles, and a few circular tubular fibers. The superficial zone of the gregarine is supposed to contribute to nutrition, thru the extensive surface furnished by its folds and thru the pinocytic vesicles; but this alimentary intake is incomplete compared with that of the previously studied anterior region. Insufficient mucus is discharged to account for locomotion. There are some circular ectoplasmic fibers, but locomotory myonemes are completely absent. However, there are deformations of the folds and corresponding waves that could account for locomotion by creeping or swimming. These movements of the folds might be due to the action of the contractile proteins and correspond with some of the layers seen in the wall.

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Bewegungsphysiologische Untersuchungen an polycystiden Gregarinen unter Anwendung des Mikrozeitrafferfilmes

Cited by 12 publications

References 7 publications

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

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

The enigma of eugregarine epicytic folds: where gliding motility originates?

L'Organisation Ultrastructurale Corticale de la Gregarine Lecudina pellucida; ses Rapports avec l'Alimentation et la Locomotion

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