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Human zona pellucida during in vitro fertilization: An ultrastructural study using saponin, ruthenium red, and osmium-thiocarbohydrazide (1992)

Familiari, Giuseppe ; Nottola, Stefania A. ; Macchiarelli, Guido ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Molecular Reproduction and Development 32 (1992), S. 51-61

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ISSN: 1040-452X

Keywords: Oocyte ; Polypronuclear ovum ; Fertilization ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology

Notes: The human zona pellucida (ZP) and its changes during in vitro fertilization in oocytes at different maturational stages and polypronuclear ova at one- to four-cells stages were studied by transmission electron microscopy (TEM) and correlative scanning electron microscopy (SEM). To define the microstructure of the ZP, its amorphous masking material was removed using a detergent (saponin), and its structural glycoproteins were stabilized with a cationic dye, ruthenium red, followed by osmium-thiocarbohydrazide treatment. These methods allowed in all samples the clear visualization of variously arranged networks of filaments composing the outer and inner surfaces of the ZP. These filaments were straight or curved, 0.1-0.4 μ in length and 10-14 nm thick as seen via TEM or 22-28 nm thick as seen via SEM (the difference in thickness was due to the presence of the metal coating for SEM). The filament arrangement was remarkably different between the inner and outer surfaces of the ZP and among the various stages studied. The filaments of the outer surface of the ZP were basically arranged in “large” and “tight” meshed networks. Mature oocytes and fertilized (polypronuclear) ova had a regular alternating pattern of wide and tight meshed networks of filaments. On the other hand, immature and atretic oocytes displayed almost exclusively a tight meshed network of filaments. The inner surface filaments of the ZP of unfertilized oocytes at any stage were arranged in repetitive structures characterized by numerous short and straight filaments anastomosing with each other and sometimes forming at the intersections small, rounded structures. After fertilization, the inner surface of the ZP displayed numerous areas where filaments fused together. Collectively, these data clearly reveal that oocyte maturation and fertilization in humans are accompanied by changes of ZP filaments arrangement, which may be relevant in the processes of binding, penetration, and selection of spermatozoa. © 1992 Wiley-Liss, Inc.

Additional Material: 6 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/mrd.1080320109

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The three-dimensional structure of the zona pellucida in growing and atretic ovarian follicles of the mouse (1989)

Familiari, Giuseppe ; Nottola, Stefania A. ; Familiari, Antonio ; [et al.]

Springer

Cell & tissue research 257 (1989), S. 247-253

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ISSN: 1432-0878

Keywords: Zona pellucida ; Ovarian follicles ; Atresia ; Ultrastructure ; Mouse

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Summary The present study provides further details on the fine-structural three-dimensional architecture of the zona pellucida (ZP) in growing and atretic follicles of mice by use of ruthenium red in combination with the detergents Triton X100 and saponin. These detergents were used for extraction of the “soluble” fraction of the zonal proteins in an attempt to expose the “structural” zonal glycoproteins, which in turn can be viewed as minute three-dimensional networks upon transmission- and scanning electron-microscopic examination. By use of these methods, the ZP of growing follicles appeared to be formed by interconnected filaments which also bind to globular structures building up a three-dimensional lattice. In contrast, the ZP of stage I as well as other (II and III) stages of atretic follicles showed a structure characterized by the presence of closely packed granules connected with short filaments to form a close-mesh reticulum. This structural change of the ZP, which in the present study is also associated with the disappearance of “gap junctions” within the granulosa and cumulus cell population, might represent one of the early events involved in the onset of atresia. These changes, most probably depending on an altered secretory activity of both oocytes and follicle cells, might lead to a degradation of the ZP network structure and to its subsequent increased density (condensation). All these morphodynamic events eventually contribute to a sequestration of the oocyte in the early stage of atresia.