Background Although ovarian tissue cryopreservation and transplantation is used for fertility preservation in patient undergoing cytotoxic treatments but obtaining good quality oocyte is still a debate. Xenotransplantation has been introduced as a reliable technique for better understanding of the transplantation conditions, but to achieve healthy embryos, the quality of obtained oocytes need t...

One of the biggest prerequisites for pregnancy is the fertilization step, where a human haploid spermatozoon interacts and penetrates one haploid oocyte in order to produce the diploid zygote. Although fertilization is defined by the presence of two pronuclei and the extraction of the second polar body the process itself requires preparation of both gametes for fertilization to take place at a ...

The specification of cell fates along the dorsoventral axis of the Drosophila embryo is dependent on the asymmetric distribution of proteins within the egg and within the egg's outer membranes. Such asymmetries arise during oogenesis and are dependent on multiple cell-cell interactions between the developing oocyte and its neighboring somatic follicle cells. The earliest known such interaction ...

Background: The biochemical characteristics of the follicular fluid (FF) play essential role in oocyte quality, the subsequent fertilization potential and embryo development. The oocyte quality and metabolism largely depends on follicular microenvironment. Present study aimed to investigate the relationship between oocyte quality and FF homocysteine (Hcy) level in women undergoing to IVF treatm...

The mammalian oocyte undertakes a highly complex journey to maturity during which it successively acquires a series of characteristics necessary for fertilization and the development of a healthy embryo. While the contribution of granulosa cells to oocyte development has been studied for many years, it has recently become apparent that the oocyte itself plays a key role in directing its own fat...

The epigenetic factors causing competence differences between SN (surrounded nucleolus) and NSN (non-surrounded nucleolus) oocytes, the significance for the increased histone acetylation and methylation in SN oocytes, and whether chromatin configuration or histone modification determines oocyte competence, are unclear. This study has addressed these issues by using the ovary-holding (OH) stress...

The inhibitor CEP-33779 is a specific selective inhibitor of JAK2. In most somatic cells, JAK2 plays essential roles in cellular signal transduction and in the regulation of cell cycle. Little is known regarding the effects of JAK2 on mammalian oocyte maturation. In the present study, we investigated the effects of CEP-33779 on mouse oocytes meiosis and possible mechanisms of JAK2 during mouse ...

We describe a cell-free extract derived from the oocytes of Xenopus laevis. The oocyte extract is capable of decondensing sperm chromatin and of replicating single-stranded DNA in a semiconservative, aphidicolin-sensitive manner. In addition, oocyte extract supports the elongation phase of DNA synthesis in nuclei that have been preinitiated for replication. All of these properties are shared by...

I N the adult hen each oocyte is surrounded by a capsule of follicle cells and all the raw materials that enter the oocyte must pass through this capsule. It is not surprising, therefore, that the morphological relationships between the follicle and the oocyte are of a highly specialized nature. Several workers have studied them, mainly by light microscopy, but their findings have not been unan...