Organization and Composition of the Amphibian Yolk Platelet. I. Investigations on the Organization of the Platelet

Ringle, David A.; Gross, Paul R.

doi:10.2307/1539593

Cited by 24 publications

(14 citation statements)

References 36 publications

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“…The precise role, if any, of yolk platelets in developmental processes is as yet ill defined, and the mechanisms of platelet formation and utilization remain a matter of speculation (7,11,16,19,22,23,31,33,50). Contradictory interpretations of yolk structure and chemistry in the current literature (9,10,16,29,30,31,34,36,39,50) show a need for a more precise understanding of these two aspects.…”

Section: Introductionmentioning

confidence: 99%

Studies on Amphibian Yolk

Karasaki

1963

The Journal of Cell Biology

135

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A B S T R A C TThe yolk platelcts of mature eggs and young embryonic cells of all amphibian species studied ( Rana pipiens, Triturus pyrrhogaster, Diemictylus viridescens, Rana nigromaculata, and Bufo vulgaris) have a superficial layer of fine particles or fibrils (ca. 50 A in diameter), a central main body with a crystalline lattice structure, and an enclosing membrane approximately 70 A in thickness. Electron micrographs of the main body reveal hexagonal net (spacing ca. 70 A), square net (spacing ca. 80 A), and parallel band (spacing from 35 to 100 A but most frequent at ca. 70 A) patterns. The crystalline structure is believed to be a simple hexagonal lattice made of closely packed cylindrical rods. Each rod is estimated to be about 80 A in diameter and 160 A in length.

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Section: Introductionmentioning

confidence: 99%

Studies on Amphibian Yolk

Karasaki

1963

The Journal of Cell Biology

135

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“…The crystalline arrangement of the lipovitellin-phosvitin subunits in the platelet has been investigated with X-ray diffraction (12,13), and electron microscopy of sectioned platelets (1,16,27,35,36). The X-ray studies provided structural data on the unit cell of the X-ray scattering elements within the platelets, and the predicted subunit spacings are in fair agreement with results of the electron microscopic studies.…”

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confidence: 70%

Amphibian yolk platelet ultrastructure visualized by freeze-etching

Leonard

Deamer

Armstrong

1972

Journal of Ultrastructure Research

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“…Polysaccharides have also been detected in the vitelline envelope that surrounds amphibian oocytes (23)(24)(25)(26)(27)(28)(29), in the cortical granules of anuran oocytes (23, 26-28, 30, 31) and in yolk platelets of anuran and urodele oocytes (23,(32)(33)(34).…”

Section: Discussionmentioning

confidence: 99%

“…A recent study of oogenesis in Pleurodeles waltlii (6) did not report the presence of any of the large granule complexes observed in the present study. Polysaccharides have also been detected in the vitelline envelope that surrounds amphibian oocytes (23)(24)(25)(26)(27)(28)(29), in the cortical granules of anuran oocytes (23, 26-28, 30, 31) and in yolk platelets of anuran and urodele oocytes (23,(32)(33)(34).…”

Section: Discussionmentioning

confidence: 99%

Polysaccharide Complexes in Full‐Grown Oocytes of the Newt, Pleurodeles, and Changes in their Distribution During Progesterone‐Induced Maturation

Charbonneau

Picheral

1985

Dev Growth Differ

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Immature full-grown oocytes of Pleurodeles waltlii contain large amounts of small electron-dense polysaccharidic granules. These granules lack a limiting membrane, and have a dense but heterogeneous matrix and an apparent diameter of 24-36 nm. Their structure, organization and distribution strongly suggest that they are glycogen granules. On the other hand, mature oocytes both after oviposition or 22-24 hr after in vitro progesterone stimulation contain no polysaccharide granules or complexes. During the first 9-10 hr after hormonal stimulation, granules were abundant and present both individually and as large strands occupying most of the space between the organelles. Granules were frequeqtly found packed together and arranged in regularly arrayed stacks within large subcortical ant cortical vacuoles. Between 4 and 6 hr after progesterone addition, oocytes released the contents of vacuoles to the outside. Between about 11 and 14 hr after progesterone addition, oocytes still contained large amounts of polysaccharide complexes, but the vacuoles were empty. From about 15 hr after progesterone treatment until the end of maturation, the complexes progressively disappeared from the cytoplasm, coincident with the detachment of the follicle cell layer from the oocytes and a reduction in the number and size of microvilli.Oocyte maturation is a complex process by which meiosis of full-grown oocytes is reinitiated starting from the stage of the first meiotic prophase and ending at the stage at which fertilization takes place, that is the second meiotic metaphase in amphibians. Full-grown urodele oocytes at stage VI of oogenesis can be induced to undergo maturation in vitro by progesterone (1-3). The earliest response to progesterone so far reported is intracellular release of calcium ions (4). Among the other most obvious early changes occurring during urodele maturation are the movement of the germinal vesicle toward the surface of the animal pole and its subsequent breakdown (3) and increase in the number of annulate lamellae until the stage of germinal vesicle breakdown (5). However, there is to date very little information available on urodele oocytes, and in fact there are onIy two reports describing and classifying the different steps of oogenesis, in Pleurodeles waltlii (6) and Triturus viridescens (7). Some particular features have been addressed, such as yolk formation (8, 9) and follicle-oocyte relations (7, 10) in developing oocytes of Triturus, annulate lamellae in developing oocytes (1 1) and in maturing oocytes (9, the cytoskeleton of full-grown oocytes (12) and the organization of the germinal vesicle and of the nucleoli of maturing oocytes of Notophthalmus (3) and Cynops (13). In the present study, a * This work on the extracellular release of polysaccharides during urodele oocyte maturation was carried out in collaboration with Bertrand Picheral, who died in 1983. This paper is dedicated to his memory. 763

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Organization and Composition of the Amphibian Yolk Platelet. I. Investigations on the Organization of the Platelet

Abstract: The importance of yolk platelets in the embryonic and larval development of amphibians is indicated by the large proportion of oocytic material contained in these dense, subcellular structures. Of the total egg nitrogen, 69-72% is found in the yolk platelet fraction (Gregg and Ballentine,

Cited by 24 publications

References 36 publications

Studies on Amphibian Yolk

Studies on Amphibian Yolk

Amphibian yolk platelet ultrastructure visualized by freeze-etching

Polysaccharide Complexes in Full‐Grown Oocytes of the Newt, Pleurodeles, and Changes in their Distribution During Progesterone‐Induced Maturation

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