Vertebrate oocytes arrest in metaphase of the second meiotic division (MII), where they maintain a high cdc2/cyclin B activity and a stable, bipolar spindle because of cytostatic factor (CSF) activity. The Mos-MAPK pathway is essential for establishing CSF. Indeed, oocytes from the mos-/- strain do not arrest in MII and activate without fertilization, as do Xenopus laevis oocytes injected with ...

Efforts to improve the quality of in vitro matured oocytes by blocking germinal vesicle breakdown (GVBD) and allowing more time for ooplasmic maturation have achieved little due to a lack of knowledge on the molecular events during GVBD blocking. Such knowledge is also important for studies aimed at regulating gene expression in maturing oocytes prior to GVBD. We studied species difference and ...

The mammalian target of rapamycin (mTOR) regulates cellular processes such as cell growth, metabolism, transcription, translation, and autophagy. Rapamycin is a selective inhibitor of mTOR, and induces autophagy in various systems. Autophagy contributes to clearance and recycling of macromolecules and organelles in response to stress. We previously reported that vitrified-warmed mouse oocytes s...

Research questionTo develop an automated sperm injection robot (ICSIA).DesignThe ICSIA the procedure, including pipette advancement, zona pellucida and oolemma penetration with piezo pulses, removal after release. The was first tested in mouse, hamster rabbit oocytes, subsequently using discarded human oocytes that were injected microbeads. Finally, we performed a small clinical pilot trial don...

Resumption of meiosis was inhibited in mouse oocyte cumulus complexes (OCC) co-cultured with pig membrane granulosa (PMG). After 3 and 6 h of co-culture these oocytes possessed an intact nuclear envelope and their nucleolar surface was associated with granules approximately 80 nm in diameter. Preincubation of OCCs for 30, 45, 60 or 90 min followed by co-culture with PMG for 2 h of either OCCs o...

conclusions the present study showed that vitrification using cryotop and freezing medium can damage oocytes by reducing the maturation and fertilization rates in both developmental stages. results vitrification caused a significant reduction in the maturation rate of oocytes. of those that matured, the fertilization rate of vitrified ivm-mii (44.1%) and ov-mii oocytes (50%) was not significant...

background: cryopreservation and in vitro maturation (ivm) of oocyte is becoming an important technique in infertility treatment and fertility preservation. also it has been proposed to establish a genetic resource bank for endangered or commercially important animal species. objective: the aim of this study was to evaluate viability, maturation and fertilization rate of mouse immature oocytes ...

To determine the requirements for gene expression in mammalian germ cells, circular double-stranded simian virus 40 (SV40) DNA molecules containing deletions in sequences controlling transcription and replication were injected into the nucleus of mouse oocytes. Expression of large (T-Ag) and small (t-Ag) tumor antigens ("early gene products") required at least three GGGCGG boxes, but did not re...

introduction: in vitro maturation and development of immature oocytes, as an artificial reproduction technique, is useful especially in women who are affected by cancer and polycystic ovary syndrome. despite using many types of in vitro media, an appropriate environment has not been reported yet. present study was designed to assess the effect of heated human follicular fluid (hhff), which is s...