The addition of alpha-amanitin to extrafollicular, cumulus-enclosed ovine oocytes at explantation inhibits meiotic maturation and prevents many of the changes in protein synthesis that normally accompany maturation. By contrast, these inhibitory effects are considerably reduced by either delaying the addition of the drug for 1-4 h or by denuding the oocytes of all associated cumulus cells at th...

The domestic ferret, Mustela putorius furos, holds great promise as a genetic model for human lung disease, provided that key technologies for somatic cell nuclear transfer (SCNT) are developed. In this report, we extend our understanding of SCNT in this species by defining conditions for efficient cell fusion by electrical pulse. Two experimental systems were employed in this study. First, in ...

Oocyte maturation is a key issue of current animal biotechnology. This study was designed to examine the morphodynamics of the cumulus-oocyte association during oocyte maturation. Porcine cumulus-oocyte complexes were recovered from slaughterhouse ovaries; matured in vitro for 0, 24, 36, and 44 h; and evaluated by scanning electron microscopy either combined or not combined with the osmium-dime...

Ovulation is the complex, inflammatory-like process by which the cumulus oocyte complex (COC) is released from a mature, preovulatory follicle through a rupture site at the ovarian surface and requires expression of genes that generate and stabilize the expanded extracellular COC matrix. Gene profiling analyses of COCs at selected time intervals during ovulation revealed that many genes associa...

CD44 is a polymorphic and polyfunctional transmembrane glycoprotein widely expressed in many types of cells. Here, the expression of this protein on human membrana granulosa was studied by two techniques. Using confocal laser scanning microscopy (CLSM) with the mouse monoclonal antibody to human CD44 (clone G44-26), cells immunoreactive for CD44 were observed in both cumulus and mural granulosa...

The elaboration of a quality oocyte is integrally linked to the correct developmental progression of cumulus cell phenotype. In humans and nonhuman primates, oocyte quality is diminished with in vitro maturation. To determine the changes in gene expression in rhesus monkey cumulus cells (CC) that occur during the final day prior to oocyte maturation and how these changes differ between in vitro...

An age-dependent acceleration of apoptosis occurs in female germ cells (oocytes), and this requires communication between the oocyte and its surrounding somatic (cumulus) cells. Here we show in aged mice that ceramide is translocated from cumulus cells into the adjacent oocyte and induces germ cell apoptosis that can be prevented by sphingosine-1-phosphate. Trafficking of ceramide requires gap ...

In the process of oocyte maturation, gonadotrophins are believed as main stimulators for oocyte meiosis resumption. However, which gonadotrophin (i.e. FSH or LH) is the key hormone in this process is still unknown. This study indicated a close relationship between LH and FSH on activating meiotic maturation of oocyte in vitro. FSH efficiently induced oocyte meiosis at concentration of 50 IU/L, ...

To fuse with oocytes, spermatozoa of eutherian mammals must pass through extracellular coats, the cumulus cell layer, and the zona pellucida (ZP). It is generally believed that the acrosome reaction (AR) of spermatozoa, essential for zona penetration and fusion with oocytes, is triggered by sperm contact with the zona pellucida. Therefore, in most previous studies of sperm-oocyte interactions i...

Pluripotent stem cells are possibly the best candidates for regenerative medicine, and somatic cell nuclear transfer (SCNT) is one of the viable options to make patient-specific embryonic stem cells. Till date efficacy of SCNT embryos is very low and requires further improvement like ideal oocyte activation and in vitro culture system. The aim of the present study was to evaluate ideal oocyte a...