• For several primary oocytes that complete meiosis I each month, only one or a few functional oocyte, the dominant follicles, completes maturation and undergoes ovulation. (wikipedia.org)
  • These protease-induced decreases in IGFBP-4 and -5 likely cause increased levels of bioavailable (or free) IGFs that stimulate steroidogenesis and mitogenesis in developing dominant follicles, which ultimately prepare the follicle(s) and oocyte(s) for successful ovulation and fertilization. (bioone.org)
  • When the inability of male transgenic rats to transmit the transgene is not associated with mosaicism, microinsemination techniques such as intracytoplasmic sperm injection (ICSI) and round spermatid injection (ROSI) can be used for passage of the transgenes. (go.jp)
  • This study was conducted to evaluate in vivo and in vitro development of in vitro-matured equine oocytes fertilized by intracytoplasmic sperm injection. (bioone.org)
  • Cumulus oophorus is a cluster of cells (called cumulus cells) that surround the oocyte both in the ovarian follicle and after ovulation. (wikipedia.org)
  • In a larger perspective, the whole folliculogenesis from primordial to preovulatory follicle is located in the stage of meiosis I of ootidogenesis in oogenesis. (wikipedia.org)
  • Within the follicle, the maintenance of oocyte meiotic arrest is primarily attributed to high cytoplasmic concentrations of cyclic adenosine monophosphate (cAMP). (bvsalud.org)
  • In the case of ROSI, round spermatids are injected into Sr 2+ -activated oocytes using a piezo-driven middle-sized pipette (5-6 μm in diameter). (go.jp)
  • Light microscopic immunofluorescent observations revealed that during acrosome biogenesis ESP first appears in the nascent acrosomal vesicle in early round spermatids and subsequently segregates to the periphery of the expanding acrosomal vesicle, thereby defining a peripheral equatorial segment compartment within flattened acrosomal vesicles and in the acrosomes of early and late cap phase, elongating, and mature spermatids. (bioone.org)
  • The nucleus of such an oocyte is called a germinal vesicle (see picture). (wikipedia.org)
  • The germinal vesicle or nucleus is located near the animal pole of the egg. (microbiologynote.com)
  • After beginning the meiotic process, the oogonia (now called primary oocytes) can no longer replicate. (wikipedia.org)
  • Therefore, understanding the pathways regulating oocyte meiotic arrest and resumption will provide detailed insight into female reproductive system and provide a theoretical basis for further research and potential approaches for novel disease treatments. (bvsalud.org)
  • Any factor interfering with this process may lead to impaired oocyte maturation, which in turn affects female reproductive function. (bvsalud.org)
  • This review describes the available information regarding the role of integrins in human reproductive physiology and discusses their clinical implications. (go.jp)
  • The embryo is the earliest stage of development and remains within the egg or reproductive organs of the mother until hatching or birth. (microbiologynote.com)
  • The primary oocyte turns into a secondary oocyte in mature ovarian follicles. (wikipedia.org)
  • The results showed a decrease in oocyte numbers in the transplanted OT, abnormal endocrine function of ovarian grafts, as well as dysfunctional mitochondria and DNA damage in the oocytes, which could adversely affect subsequent embryonic development. (bvsalud.org)
  • These structures are periodically initiated to grow and develop, culminating in ovulation of usually a single competent oocyte in humans. (wikipedia.org)
  • Once a month, one of the ovaries releases a mature egg (ovum), known as an oocyte. (wikipedia.org)
  • Oocytes were collected from slaughterhouse-derived ovaries, matured in vitro, and injected with frozen-thawed stallion sperm. (bioone.org)
  • and the development of embryos after in vitro fertilisation. (bvsalud.org)
  • Two-cell stage embryos derived from the mating of transgenic rats with wild-type rats can be successfully cryopreserved by conventional two-step freezing in the presence of 10% dimethylsulfoxide. (go.jp)
  • Our ICSI procedure includes the use of a piezo-driven small-sized injection pipette (2-4 μm in diameter), isolated sperm heads, and freshly ovulated oocytes. (go.jp)
  • These microinsemination techniques can be combined with cryopreservation of sperm and spermatid cells, leading to successful transmission of transgenes carried in male gametes. (go.jp)
  • PMPCB encodes the catalytic subunit of the essential mitochondrial processing protease (MPP), which is required for maturation of the majority of mitochondrial precursor proteins. (regenerativemedicine.net)
  • The study of embryo development is known as embryology, which is a branch of biology dedicated to understanding the processes and stages of embryonic growth. (microbiologynote.com)
  • In Drosophila melanogaster, 16 interconnected cells form a germline cyst, where one cell differentiates into an oocyte, while the rest become nurse cells that supply the oocyte with mRNAs, proteins, and organelles through intercellular cytoplasmic bridges named ring canals via microtubule-based transport. (bvsalud.org)
  • In human female primordial germ cells, the transition from mitosis to meiosis begins from the fetal stage. (bvsalud.org)
  • In germ cells, meiosis is arrested at the diplotene stage of prophase in meiosis I (MI) after synapsis and recombination of homologous chromosomes, which cannot be segregated. (bvsalud.org)
  • During estrus phase in animals or the menstrual cycle in humans, the resumption of meiosis occurs in certain oocytes due to a surge of luteinizing hormone (LH) levels. (bvsalud.org)
  • To provide a comprehensive understanding of the recently uncovered regulatory network involved in oocyte development and maturation, the progress of the cellular and molecular mechanisms of oocyte nuclear maturation including meiosis arrest and meiosis resumption is summarized. (bvsalud.org)
  • In humans, oocytes are established in the ovary before birth and may lie dormant awaiting initiation for up to 50 years. (wikipedia.org)
  • Further knowledge of the integrin-mediated regulation of cell growth and cell survival may facilitate our understanding of many key aspects of development and physiology in reproduction. (go.jp)
  • In vivo development was assessed after transfer of injected oocytes to the oviducts of recipient mares. (bioone.org)
  • For in vitro culture of follicles, there are various techniques to optimize the growth of follicles, including the use of defined media, growth factors and three-dimensional extracellular matrix support. (wikipedia.org)
  • Knockdown of msps blocks the oocyte growth and causes gradual loss of oocyte determinants. (bvsalud.org)
  • Each of them contains a single oocyte (immature ovum or egg cell). (wikipedia.org)
  • Translated Msps stimulates microtubule polymerization in the oocyte, causing more microtubule plus ends to grow from the oocyte through the ring canals into nurse cells, further enhancing nurse cell-to-oocyte transport by dynein. (bvsalud.org)
  • Thus, the Msps-dynein duo creates a positive feedback loop, ensuring oocyte fate maintenance by promoting high microtubule polymerization activity in the oocyte, and enhancing dynein-dependent nurse cell-to-oocyte transport. (bvsalud.org)
  • Addressing those 'big questions' of high societal relevance have the merit of creating high visibility and also funding opportunities, however, classic comparative physiology and biochemistry is running the risk of becoming marginalized in this process, if the underlying physiological and biochemical processes cannot be visualized accordingly. (easychair.org)
  • Depending on the specific species, oocytes can remain arrested for extended periods of time, ranging from months to even years. (bvsalud.org)
  • In this study, we find that a microtubule polymerase Mini spindles (Msps), the Drosophila homolog of XMAP215, is essential for maintenance of the oocyte specification. (bvsalud.org)
  • This 'resting phase' or dictyate stage can last anywhere up to fifty years in the human. (wikipedia.org)
  • Based on these observations, we propose a new model of acrosome biogenesis in which the equatorial segment is defined as a discrete domain within the acrosomal vesicle as early as the Golgi phase of acrosome biogenesis. (bioone.org)