We report on a binuclear human oocyte that underwent maturation in vitro from germinal vesicle stage to metaphase II. Following extrusion of two polar bodies, the oocyte was processed for cytogenetic analysis which revealed two separate haploid chromosome sets accompanied by the corresponding polar body chromatin. Tentatively established karyotypes were 23,X and 23,X,ace, respectively. This con...

Porcine immature oocyte quality (i.e., that of live oocytes at the germinal vesicle stage) was evaluated according to features of the surrounding cumulus, aiming to establish maturational competence of different subpopulations of such cumulus-oocyte complexes. Six subpopulations were identified: A1 (with a dense cumulus), A2 (with a translucent cumulus), B1 (with the corona radiata), B2 (partly...

The growth of vertebrate oocyte stops temporarily at the late diplotene stage of 1 meiotic cell division and stays at that stage until puberty. Before ovulation, the arrest is resumed and enters the 2 meiotic phase and stops again at the metaphase until fertilization. The arrest is mediated by the constant flow of cAMP, which is generated by activated adenylyl cyclase. This state is manifested ...

a:4:{s:10:"Background";s:206:"The aim of the present study was to investigate the role of progesterone on the developmental competence of cumulus-oocyte complexes (COCs) and cumulus-denuded oocytes (CDOs) at germinal vesicle (GV) stage.";s:19:"MaterialsAndMethods";s:485:"GV oocytes of pregnant mare's serum gonadotropin (PMSG)-primed prepubertal mice were divided into two groups: CDOs and COCs. ...

PURPOSE OF REVIEW To evaluate current and previous findings related to a timely implementation of in-vitro maturation (IVM) of germinal vesicle, metaphase I and metaphase II oocytes with an optimal cryopreservation to determine whether IVM should be attempted prior to (fresh IVM) or IVM after cryopreservation (postthaw IVM). Mitochondrion, chromatin and spindle formation in both groups were int...

High resolution two-dimensional electrophoresis has been used to examine the pattern of protein synthesis during meiotic maturation of mouse oocytes in vitro. Fluorograms of [35S]methionine-labeled oocyte proteins have revealed that meiotic progression from dictyate to metaphase II (meiotic maturation) is accompanied by marked changes in the pattern of proteins synthesized by oocytes. Virtually...

Although securin/separase/cohesion pathway was reported to regulate chromosome segregation during meiotic metaphase-to-anaphase transition, little biochemical evidence was provided. We recently found that oocytes could not progress beyond meiotic metaphase when ubiquitin-proteasome pathway was inhibited, but the mechanisms remain unclear. In the present study, we investigated the quantity of se...

The mammalian oocyte possesses powerful reprogramming factors, which can reprogram terminally differentiated germ cells (sperm) or somatic cells within a few cell cycles. Although it has been suggested that use of oocyte-derived transcripts may enhance the generation of induced pluripotent stem cells, the reprogramming factors in oocytes are undetermined, and even the identified proteins compos...

The present studies have been undertaken to investigate the interactions that occur between the nucleus and cytoplasm of ovine oocytes at various stages during meiotic maturation. We report that the nucleus of ovine fully grown dictyate stage oocytes can be efficiently removed by a microsurgical enucleation procedure. It is demonstrated that between the initiation of maturation and germinal ves...

the changes of total calcium content of persian sturgeon, acipenser persicus follicles were investigated during different stages of germinal vesicle migration. total calcium content increased during maturation and ripening of the oocytes i.e. migration of nucleus toward the animal pole. according to data, the total calcium of follicles with polarization index (pi: the ratio of the distance of t...