Amino Acid transport mechanisms in mouse oocytes during growth and meiotic maturation. (73/273)

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Functional roles of mouse sperm hyaluronidases, HYAL5 and SPAM1, in fertilization. (74/273)

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LH/hCGR gene expression in human cumulus cells is linked to the expression of the extracellular matrix modifying gene TNFAIP6 and to serum estradiol levels on day of hCG administration. (75/273)

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Cumulus-associated alpha2-macroglobulin derivative retains proconceptive glycodelin-C in the human cumulus matrix. (76/273)

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Differential effects of follistatin on nonhuman primate oocyte maturation and pre-implantation embryo development in vitro. (77/273)

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Follicular size is associated with the levels of transcripts and proteins of selected molecules responsible for the fertilization ability of oocytes of puberal gilts. (78/273)

The maturation and developmental competence of the oocyte is acquired during folliculogenesis. It is still unclear whether follicle size is associated with the levels of transcript and protein encoding molecules contributing to the fertilization ability of the porcine oocyte. Follicles were dissected from porcine ovaries after slaughter and classified as small (< 3 mm), medium (3-5 mm) or large (>5 mm), aspirated cumulus-oocyte complexes were cultured in standard porcine IVM culture medium (TCM 199) for 44 h. In developmentally competent oocytes, assessed by determining the activity of glucose-6-phosphate dehydrogenase (G6PDH) using a brilliant cresyl blue (BCB) test, real-time quantitative PCR reaction methods, western-blot and confocal microscopy analysis were applied to determine the transcript levels of porcine zona pellucida glycoproteins pZP1, pZP2, pZP3, pZP3 alpha and integrins beta 1 and beta 2, as well as the levels of pZP3 and integrin beta 2 proteins. We observed significantly higher levels of pZP1, pZP3 and integrin beta1 and beta2 transcripts in oocytes collected from medium follicles as compared with small follicles (P<0.001). Moreover, we found an increased content of all investigated mRNAs in oocytes isolated from large follicles as compared with small follicles (P<0.001). Western-blot analysis demonstrated a higher level of pZP3 protein in oocytes isolated from large and medium follicles as compared with small follicles (P<0.001). Our results suggest that the levels of transcripts and proteins for selected molecules contributing to the fertilization ability of oocytes are associated with follicular size in puberal gilts.  (+info)

Effect of donor cell types on developmental potential of cattle (Bos taurus) and swamp buffalo (Bubalus bubalis) cloned embryos. (79/273)

This study investigated the effect of donor cell types on the developmental potential and quality of cloned swamp buffalo embryos in comparison with cloned cattle embryos. Fetal fibroblasts (FFs), ear fibroblasts (EFs), granulosa cells (GCs) and cumulus cells (CCs) were used as the donor cells in both buffalo and cattle. The cloned cattle or buffalo embryos were produced by fusion of the individual donor cells with enucleated cattle or buffalo oocytes, respectively. The reconstructed (cloned) embryos and in vitro matured oocytes without enucleation were parthenogenetically activated (PA) and cultured for 7 days. Their developmental ability to the blastocyst stage was evaluated. The total number of trophectoderm (TE) and inner cell mass (ICM) cells and the ICM ratio in each blastocyst was determined by differential staining as an indicator of embryo quality. The fusion rate of CCs with enucleated oocytes was significantly lower than for those of other donor cell types both in cattle and buffalo. The rates of cleavage and development to the 8-cell, morula and blastocyst stages of cloned embryos derived from all donor cell types did not significantly differ within the same species. However, the cleavage rate of cloned cattle embryos derived from FFs was significantly higher than those of cattle PA and cloned buffalo embryos. The blastocyst rates of cloned cattle embryos, except for the ones derived from CCs, were significantly higher than those of cloned buffalo embryos. In buffalo, only cloned embryos derived from CCs showed a significantly higher blastocyst rate than that of PA embryos. In contrast, all the cloned cattle embryos showed significantly higher blastocyst rates than that of PA embryos. There was no difference in ICM ratio among any of the blastocysts derived from any of the donor cell types and PA embryos in both species. FFs, EFs, GCs and CCs had similar potentials to support development of cloned cattle and buffalo embryos to the blastocyst stage with the same quality.  (+info)

Effects of season and reproductive phase on the quality, quantity and developmental competence of oocytes aspirated from Japanese black cows. (80/273)

The aim of the present study was to determine whether the season (hot and cool) and reproductive phase (pregnant and non-pregnant) of the cow affect follicular recruitment and oocyte development. Follicular oocytes were aspirated from Japanese black cows by the ovum pick-up (OPU) method, which was performed 2 to 6 times within 1.5 months in pregnant cows and 2 to 4 times within 2 months in non-pregnant cows, during the hot (July to September) and cool (October to November) seasons. After follicular aspiration, the number and morphology of cumulus-oocyte complexes (COCs) and the developmental competence of oocytes after in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture were evaluated. The quality of aspirated COCs did not differ between the hot and cool seasons, irrespective of the reproductive phase of the donor cows. In the pregnant cows, the season did not affect follicular recruitment, early embryonic development or the quality of embryos. In the non-pregnant cows, however, the mean number of aspirated follicles and collected oocytes decreased during the hot season as compared with the cool season. When the data for the 2 seasons were combined to assess the effects of reproductive phase on oocyte development, the total proportions of cleavage, development into blastocysts and freezable embryos were higher for embryos obtained from pregnant cows (P<0.05) than those obtained from non-pregnant cows. In conclusion, the season did not have any apparent effects on the quality of aspirated COCs and the developmental competence of oocytes after IVM-IVF, but it may affect follicular recruitment in non-pregnant cows. Moreover, the reproductive phase may influence the developmental competence of the recovered oocytes.  (+info)