Cell cycle, morphogenesis, and ultrastructure in the pseudoheliozoan clathrulina elegans

Bardele, Christian F.

doi:10.1007/bf00306959

Cited by 49 publications

(5 citation statements)

References 12 publications

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“…5 c, D). These bodies can be characterized as true kinetocysts (Bardele, 1971(Bardele, , 1972(Bardele, , 1975. A similar assemblage of different kinds of extrusomes has also been observed in other protozoa but the significance of this variation is not explained (see Hausmann, 1978).…”

Section: Extrusive Organellesmentioning

confidence: 73%

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Behaviour and cytology ofActinocoryne contractilis, nov. gen., nov. sp., a new stalked heliozoan (Centrohelidia): comparison with the other related genera

Febvre-Chevalier

1980

J. Mar. Biol. Ass.

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Section: Extrusive Organellesmentioning

confidence: 73%

“…x 450. (Bardele, 1972), is quite evident along both stalk and axopodia. The time-lapse sequences of our film (Febvre-Chevalier & Febvre, 1979) 1 have shown that these 'saltatory movements' are similar to those studied in other Heliozoa Actinophrydia (Troyer, 1975), or Centrohelidia (Davidson, 1973).…”

Section: Morphological Characters Of the Stalked Phasementioning

confidence: 97%

Behaviour and cytology ofActinocoryne contractilis, nov. gen., nov. sp., a new stalked heliozoan (Centrohelidia): comparison with the other related genera

Febvre-Chevalier

1980

J. Mar. Biol. Ass.

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“…While this hypothesis of disk function is thus quite attractive, one other possibility should be entertained: the disk membranes could conceivably serve to permit a transient stretching of the gullet and cytopharynx while relatively large prey organisms (like Tetrahymena) are being squeezed through the ordinarily narrow cytopharyngeal opening, following which the disks could reform as the cytopharynx collapsed to its normal dimensions. In this case the disks could play a role similar to that postulated for the thick-membraned fusiform vesicles in the transitional epithelial cells of the mammalian urinary tract during cycles of stretching and contraction (Hicks, 1966;see Falk, 1969, andBardele, 1972, for descriptions of similar vesicles in algal cells and pseudoheliozoan protozoa, respectively). This possibility is made less plausible because of the myeloid material ejected from the disks following their fusion with the cell membrane; it again would seem that recapture of this material by disks forming endocytotically from the wall of the buccal cavity might be difficult.…”

Section: Role Of the Pharyngeal Disks In The Feeding Processmentioning

confidence: 71%

Feeding in ciliated protozoa: I. pharyngeal disks in Euplotes: A source of membrane for food vacuole formation?

Kloetzel

1974

Journal of Cell Science

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The ciliate Euplotes is able to expend a very large amount of membrane in the formation of food vacuoles. Calculations based on the rate of ingestion of the food organism Tetrahymena indicate that an amount of food vacuole membrane equivalent to approximately 50-150% of the total Euplotes cell surface area can be produced within 5-10 min. An aggregation of osmiophilic, membrane-limited ‘pharyngeal disks’ is found packed in the cytoplasm just beneath the cell surface membrane in the region of the cell mouth and cytopharynx. These disks, which can be seen also in living cells, have average dimensions of 2 µm diameter by 100 nm thickness, and contain tightly packed layers of a thin lamellar material. Electron micrographs have revealed the apparent fusion of the limiting membrane of disks with the cell's plasma membrane at the base of the gullet. The lamellar disk contents are thereby released to the exterior medium in the buccal cavity, where they form a loosely packed layer over the surface membrane. It is postulated that the pharyngeal disks represent a repository of preformed membrane for use in food vacuole formation. The disk contents may also play a role in food ingestion, although this is not well defined at present. The myeloid content of old food vacuoles is very similar to that of nearby disks in the cytoplasm, suggesting that the disks may form by pinching from shrinking food vacuoles during the digestive cycle. Thus a cycle of membrane flow is envisaged, with the pharyngeal disks (1) coalescing with the surface membrane during food vacuole formation, (2) reforming by pinching from these food vacuoles during digestion, and (3) migrating back to the oral region to serve as a membrane store for subsequent food vacuole formation.

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“…Or, la comparaison de ces figures avec celles donnCes par les stocks de membranes des kystes de d u d e et destints & engendrer les plis corticaux nous conduit i penser que chez les trophontes, les vksicules oblongues seraient des membranes de remplacement. La prCsence de tels stocks membranaires a Ct C dCmontrCe chez d'autres Protistes, en rapport avec la phagotrophie (3, l o ) , la phagotrophie et la locomotion (9, 14), la croissance d'axopodes ( 2 ) . Chez les Opalines, l'accroissement d u plasmalemme, ou la compensation des pertes pourraient tgalement se faire par incorporation d'C1Cments membranaires prCassemblCs.…”

Section: Morphogkndse Corticaleunclassified

Etude Ultrastructurale de Différents Types de Kystes d'Opalines

Mignot

Brugerolle

1974

The Journal of Protozoology

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RESUME Deux types de structure kystique ont été observés au microscope éectronique. Dans le ler, qui correspond aux kystes d'infection ou gamontokystes, la cellule est relativement libre dans l'enveloppe kystique. Celle‐ci est formée de 2 couches distinctes d'inégale épaisseur (ectokyste, endokyste) sécrétées par la cellule et doublées intérieurement par un mince feuillet cytoplasmique dûà une extension des plis cuticulaires. C'est la seule modification du cortex cellulaire. Par contre, dans le 2ème type les modifications sont beaucoup plus importantes. La cellule est étroitement accolée aux parois du kyste; crêtes et flagelles ont disparu de la surface. Cependant on retrouve leurs traces dans la région corticale, sous forme d'axonèmes intracytoplasmiques plus ou moins désorganisés et d'empilements de saccules associés à des rangées de microtubules. Ce seraient des kystes de résistance. Les structures observées dans ces derniers kystes nous permettent de discuter quelques idées sur la participation des microtubules et des systèmes membranaires à la morphogénèse du cortex des Opalines.

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Cell cycle, morphogenesis, and ultrastructure in the pseudoheliozoan clathrulina elegans

Cited by 49 publications

References 12 publications

Behaviour and cytology ofActinocoryne contractilis, nov. gen., nov. sp., a new stalked heliozoan (Centrohelidia): comparison with the other related genera

Behaviour and cytology ofActinocoryne contractilis, nov. gen., nov. sp., a new stalked heliozoan (Centrohelidia): comparison with the other related genera

Feeding in ciliated protozoa: I. pharyngeal disks in Euplotes: A source of membrane for food vacuole formation?

Etude Ultrastructurale de Différents Types de Kystes d'Opalines

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