L'appareil de Golgi des Ciliés. Ultrastructure, particulièrement chez <i>Paramecium</i>

Esteve, Jean-Claude

doi:10.1111/j.1550-7408.1972.tb03543.x

Cited by 30 publications

(9 citation statements)

References 30 publications

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“…Our observations on the organization of the Golgi stack confirm those previously reported by Hausmann [15] in P dubius, and this organization is similar to that reported in Paramecium [2,8]. In these cells the Golgi stack and its surrounding cytoplasm includes: 1) an endoplasmic reticulum containing a smooth region and frequently associated with a mitochondrion or other organelle; 2) transition vesicles, which have a non-bristle coat, are closely apposed to the cis face of the Golgi stack and form from the smooth region of the endoplasmic reticulum; 3) 1-3 Golgi cisternae; and 4) coated or non-coated vesicles located near the trans cisterna.…”

Section: The Golgi Systemsupporting

confidence: 92%

Secretory organelle biogenesis: Trichocyst formation in a ciliated protozoan

Peck

Swiderski

Tourmel

1993

Biology of the Cell

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By classical electron microscopy and immunoelectron microscopy, the biogenesis of trichocyst secretory granules has been followed in the ciliated protozoan Pseudomicrothorax dubius. The very early pre-trichocysts form by fusion of bristle-coated, electron-dense vesicles (dense vesicles) with electron-translucent vesicles (clear vesicles), both of which originate in a well-developed trans-Golgi network (TGN). The pre-trichocyst grows by further fusion with dense and clear vesicles as well as with other pre-trichocysts until it reaches its maximum diameter of about 2 μm. Dense and clear vesicle formation from the TGN has been followed, and the fusion sequence of dense vesicles with the pre-trichocyst has been documented. The contents of the dense vesicles are the precursors of the trichocyst tip, which is composed of four arm-like rods, whereas the shaft precursors are supplied by the clear vesicles. The first evidence of trichocyst shaft formation is the appearance of a paracrystalline, dense core condensation center in the pre-trichocyst. Following shaft formation, the trichocyst tip forms by fusion and condensation of the dense arm precursors along each of the four sides of the shaft. Docking of the fully formed trichocyst in the cell cortex is described. Pre-trichocyst biogenesis in cells grown with and without Se is compared

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Section: The Golgi Systemsupporting

confidence: 92%

Secretory organelle biogenesis: Trichocyst formation in a ciliated protozoan

Peck

Swiderski

Tourmel

1993

Biology of the Cell

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“…nSAg pass through the numerous dictyosomes [25,31] corresponding to the number of randomly scattered intracellular fluorescent dots in CLSM analyses (data not shown).…”

Section: Discussionmentioning

confidence: 99%

Immunolabeling analysis of biosynthetic and degradative pathways of cell surface components (glycocalyx) in Paramecium cells

Flötenmeyer

Momayezi

Plattner

1999

European Journal of Cell Biology

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Cell surface -glycocalyx -immuno-labelingParameciumBiosynthetic and degradative pathways of glycocalyx components are largely unknown in Paramecium and in some related parasitic protozoa. We isolated cell surface (glyco-)proteins. i.e .. surface antigens (SAg) and used them in the native (nSAg) or denatured (dSAg) state to produce antibodies (AB) for immunolocalization by confocal imaging and by quantitative immunogold EM-labeling of ultrathin sections or of freeze-fracture replicas. Antibodies against nSAg or dSAg, respectively, yield different labeling densities over individual structures, thus indicating biosynthetic or degradative pathways, respectively. We derive the following biosynthetic way: ER~Golgi apparatus~non-regulated/non-dense core vesicle transport~diffusional spread over non-ciliary (somatic) and ciliary cell membrane. For degradation we show the following pathways: Concentration of nSAg in the cytostome~nascent digestive vacuole~mature vacuolesr elease of dSAg at cytoproct, with partial retrieval by "discoidal vesicles". A second internalization pathway proceeds via coated pits ("parasomal sacs")~early endosomes ("terminal cisternae")d igestive vacuoles. Dense packing of SAg in the glycocalyx may drive them into the endo-/phagocytic pathway. Still more intriguing is the site of nSAg integration into the cell membrane by unstimulated exocytosis. We consider unconspicuous clear vesicles relevant for nSAg export, probably via sites which most of the time are occupied by coated pits. This could compensate for membrane retrieval by coated pits, while scarcity of smooth profiles at these sites may be explained by the much longer time period required for coated pit formatiou as compared to exocytosis.

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“…5B). According to size, form and position, as well as their number these structures may correspond to the numerous Golgi elements found in Paramecium (Estève, 1972). In immunogold EM analysis, label was enriched at the boundary of the rough ER (Fig.…”

Section: Cyclosismentioning

confidence: 99%

A broad spectrum of actin paralogs inParamecium tetraureliacells display differential localization and function

Sehring

Reiner

Mansfeld

et al. 2007

Journal of Cell Science

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To localize the different actin paralogs found in Paramecium and to disclose functional implications, we used overexpression of GFP-fusion proteins and antibody labeling, as well as gene silencing. Several isoforms are associated with food vacuoles of different stages. GFP-actin either forms a tail at the lee side of the organelle, or it is vesicle bound in a homogenous or in a speckled arrangement, thus reflecting an actin-based mosaic of the phagosome surface appropriate for association and/or dissociation of other vesicles upon travel through the cell. Several paralogs occur in cilia. A set of actins is found in the cell cortex where actin outlines the regular surface pattern. Labeling of defined structures of the oral cavity is due to other types of actin, whereas yet more types are distributed in a pattern suggesting association with the numerous Golgi fields. A substantial fraction of actins is associated with cytoskeletal elements that are known to be composed of other proteins. Silencing of the respective actin genes or gene subfamilies entails inhibitory effects on organelles compatible with localization studies. Knock down of the actin found in the cleavage furrow abolishes cell division, whereas silencing of other actin genes alters vitality, cell shape and swimming behavior.

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L'appareil de Golgi des Ciliés. Ultrastructure, particulièrement chez Paramecium

Cited by 30 publications

References 30 publications

Secretory organelle biogenesis: Trichocyst formation in a ciliated protozoan

Secretory organelle biogenesis: Trichocyst formation in a ciliated protozoan

Immunolabeling analysis of biosynthetic and degradative pathways of cell surface components (glycocalyx) in Paramecium cells

A broad spectrum of actin paralogs inParamecium tetraureliacells display differential localization and function

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