We recently identified Xenopus Rho-associated protein kinase alpha (xROKalpha) as a Xenopus insulin receptor substrate-1 binding protein and demonstrated that the non-catalytic carboxyl terminus of xROKalpha binds Xenopus insulin receptor substrate-1 and blocks insulin-induced MAP kinase activation and germinal vesicle breakdown in Xenopus oocytes. In the current study we further examined the r...

In order to achieve developmental competence, porcine oocytes must undergo both nuclear and cytoplasmic maturation. Nuclear maturation results from breakdown of the germinal vesicle (GV) and progression of meiosis to metaphase II (MII). Cytoplasmic maturation is the accumulation, within the oocyte’s cytoplasm, of products necessary for fertilization, cleavage and development, prior to activatio...

Background: Heat shock may affect different aspects of oocyte maturation and its subsequent development to the blastocyst stage. A series of in vitro experiments was performed to determine whether physiologically heat shock (41°C) disrupts the progression of the ovine oocytes through meiosis, activation and blastocyst formation. Materials and Methods: The cumulus-oocyte complexes (COCs) were as...

Introduction Meiosis is a special type of cell division through which haploid gametes are generated from diploid parent cells. This is accomplished by a first division that induces homologous chromosome segregation followed by a second mitosis-like division that promotes sister chromatid separation. During the prophase of meiosis I, three basic events take place: pairing of homologous chromosom...

introduction: the purpose of this study was to evaluated the effect of β-mercaptoethanol on resumption of meiosis, in vitro maturation of immature mouse oocytes and resulting embryo development with and without bso (dl-buthionine sulfoximine). material and methods: germinal vasicle (gv) were recovered from 6-8 weeks old nmri ovaries and cultured in maturation medium in memα supplemented with 7....

Mammalian female germ cells enter meiosis during fetal development and, depending on species, they arrest at prophase of the first meiosis formonths or years after birth. During follicle development, oocytes are still arrested at this stage although their size increases significantly. Only after puberty will the fully grown oocytes resume the first meiosis upon gonadotropin stimulation of the s...

An option for fertility preservation for women facing a cancer diagnosis involves the cryopreservation of ovarian tissue for later re-transplantation or in vitro culture, with in vitro culture preferred to avoid reintroduction of the cancer. Small, immature follicles survive the freeze-thaw process, and can be matured through in follicle maturation (IFM) that involves an initial growth of the f...

25 In the physiological condition, mammalian oocytes and embryos appears to be stimulated not only chemically but also mechanically, such as compression, shear stress and/or friction force in the follicle and female reproductive tract. The present study was undertaken to examine the effects of kinetic culture with a tilting device in chemically defined media during in vitro maturation (IVM) of ...