Preparation of young preactivated oocytes with high enucleation efficiency for bovine nuclear transfer
| Autor: | Mohamed Sayed Mohamed Nour, Yoshiyuki Takahashi |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Enucleation
chemistry.chemical_element Cycloheximide Calcium Biology Cytoplast Andrology chemistry.chemical_compound Polar body Oogenesis Food Animals Animals Small Animals Calcimycin Metaphase Cell Nucleus Protein Synthesis Inhibitors Ionophores Equine Embryo Blastomere Embryo Transfer Molecular biology Chromatin chemistry Oocytes Animal Science and Zoology Cattle |
| Zdroj: | Theriogenology. 51(3) |
| ISSN: | 0093-691X |
| Popis: | To improve the enucleation rate in newly matured bovine oocytes, we investigated the position of cytoplasmic chromatin in relation to the polar body and the consequent enucleation efficiency before and after sequential activation with calcium ionophore A23 187 and cycloheximide. Oocytes aspirated from the follicles of slaughterhouse-collected ovaries were cultured for 18 to 20 h. With Hoechst staining, only 40.7% of the chromatin material was found adjacent to the first polar body in metaphase II oocytes, while 100% was located adjacent to the second polar body in oocytes after the activation. Enucleation trials after activation showed a higher enucleation rate (91.5%) than that before activation (59.9%). The following experiment determined the effect of using both kinds of cytoplast on the in vitro development of nuclear transfer embryos. Blastomeres of the 32-cell-stage in vitro-produced embryos were transferred, fused to the activated cytoplasts and cultured in vitro. No significant difference was detected in fusion, cleavage or development to blastocysts obtained 7 d (174 h) post fusion. In conclusion, this study showed that young in vitro-matured bovine oocytes sequentially activated with calcium ionophore and cycloheximide have cytoplasmic chromatin material adjacent to the second polar body, leading to a high enucleation rate. |
| Databáze: | OpenAIRE |
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