The zona pellucida is a thick extracellular coat that surrounds all mammalian eggs and preimplantation embryos. The zona pellucida supports communication between oocytes and follicle cells during oogenesis; protects oocytes, eggs, and embryos during development, and regulates interactions between ov
Fine structure of the zona pellucida of unfertilized egg cells and embryos
✍ Scribed by Barańska, Wanda ;Konwiński, Marian ;Kujawa, Marek
- Book ID
- 102890044
- Publisher
- John Wiley and Sons
- Year
- 1975
- Tongue
- English
- Weight
- 891 KB
- Volume
- 192
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
The fine structure of the zona pellucida of mouse unfertilized egg cells and of mouse embryos was investigated. In addition to standard fixation for electron microscopy, fixation with an addition of ruthenium red was used and found to be especially valuable for the purpose of studying the zona pellucida.
The zona pellucida of unfertilized egg cells and of embryos consisted mainly of fibrillar and granular material. There were two layers: a thicker internal and a denser external layer in the zona pellucida of the unfertilized egg cells. The zona pellucida of embryos had, in addition to these two layers, a coarsegrained intimal layer inside the internal layer and a fine‐grained peripheral layer outside the external layer. The intimal layer seems to be the product of cortical reaction whereas the peripheral layer can be accumulated and modified during the passage of the embryo through the female genital tract. The influence of developmental events and environmental factors on the fine structure of zona pellucida was discussed.
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Sheep eggs were obtained at appointed times from 4 to 16 hours after ovulation and examined for evidence of penetration by spermatozoa. The following observations were made: ( 1 ) The fertilizing spermatozoon makes a curved slit in the zona as a result of traversing it. The slit seems to be an open
## Abstract The mammalian zona pellucida (ZP) is an extracellular matrix surrounding oocytes and early embryos, which is critical for normal fertilization and preimplantation development. It is made up of three/four glycoproteins arranged in a delicate filamentous matrix. Scanning electron microsco