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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 41 (1995), S. 459-467 
    ISSN: 1040-452X
    Keywords: Vimentin ; Keratin ; Desmin ; Immunohis-tochemistry ; Ovary ; Bovine ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The distribution of the intermediate filament (IF) proteins desmin, keratin, and vimentin was studied immunohistochemically in bovine ovaries. Special attention was paid to granulosa cells to examine possible marked changes of IF distribution in relation to folliculogenesis during ovarian development. Therefore, ovaries were used from fetuses from 3 months of gestation onward, calves, heifers, and cows. In all ovaries, desmin immunoreactivity was restricted to smooth muscle cells in blood vessel walls. Keratin appeared a characteristic of the ovarian surface epithelium. Co-localization of keratin and vimentin was observed in the epithelium of rete ovarii tubules in fetuses and calves, and in cortical cord epithelium and pregranulosa cells of primordial follicles in fetuses at 3-7 months of gestation. Vimentin was demonstrated in endothelium and in fibroblasts. In addition, vimentin immunoreactivity was present in granulosa cells of primary, secondary, and antral follicles. In antral follicles, these granulosa cells mainly had an elongated appearance and either contained an oblong or a round nucleus. Those with an oblong nucleus were characteristic for atretic antral follicles. In nonatretic follicles, numerous vimentin immunore-active, elongated granulosa cells with a round nucleus were observed, especially in the peripheral granulosa layer and in small (〈3 mm in diameter) antral follicles. Additionally, in antral follicles, protrusions of vimentin-positive corona radiata cells were observed, that penetrated the zona pellucida to contact the oocyte. The data show that the distribution of vimentin containing IFs is associated with various aspects of granulosa cell activity, as mitosis, atresia, and intercellular transport. © 1995 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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  • 2
    ISSN: 1040-452X
    Keywords: Cow ; In vitro maturation ; Inhibitors ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Bovine cumulus oocyte complexes were cultured for various periods and either denuded and orcein stained or radiolabeled with 35S-methionine or 32P-orthophosphate. Specific inhibitors were added to the culture medium to investigate mRNA and protein synthesis requirements for both nuclear and cytoplasmic changes during maturation in vitro. Inhibition of mRNA synthesis by α-amanitin during the first 2 h of culture prevented the phosphorylation of some specific proteins preceding GVBD and decreased the occurrence of GVBD from 97% to 27%. In addition, in oocytes that had undergone GVBD, only part of the changes in protein synthesis after GVBD were observed. Addition of α-amanitin after 3 h of culture had no effect on meiotic maturation. When cumulus oocyte complexes were cultured in the presence of cycloheximide, the phosphorylation of specific proteins was also blocked and only 5% of the oocytes underwent GVBD. Addition of cycloheximide after 4, 6, or 8 h of culture resulted in an increasing percentage of GVBD, but the oocytes became arrested in metaphase I. When cycloheximide was added from 12 h of culture onwards, nuclear progression to metaphase II was increasingly restored.It is concluded that after the onset of culture, both mRNA and protein synthesis are necessary for the phosphorylation of specific proteins and for GVBD. Further-more, transcription during the first hours of culture is needed for the synthesis of new proteins after GVBD.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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