Spindle formation chromosome in vitro oocyte maturation techniques. Medical search. Frequent questions

Second Polar Body (Discarded afterward) + Ovum Oocyte meiosis, important to all animal life cycles yet unlike all other instances of animal cell division, occurs completely without the aid of spindle-coordinating centrosomes. (wikipedia.org)
Oogonia enter meiosis during embryonic development, becoming oocytes. (wikipedia.org)
Removal of the oocyte from the follicle causes meiosis to progress in the oocyte. (wikipedia.org)
As follicles grow, they acquire receptors for luteinizing hormone, a pituitary hormone that reinitiates meiosis in the oocyte and causes ovulation of a fertilizable egg. (wikipedia.org)
Because the granulosa cells and oocyte are connected by gap junctions, cyclic GMP also decreases in the oocyte, causing meiosis to resume. (wikipedia.org)
In those men in whom spermatogenesis is blocked at the stage of round spermatids, in which meiosis has already been completed, these round cells can successfully fertilize oocytes after being injected into their cytoplasm. (wikipedia.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)
It is well known that c-Jun N-terminal kinase (JNK) plays pivotal roles in various mitotic events, but its function in mammalian oocyte meiosis remains unknown. (cambridge.org)
It was found that FIGNL1, a member of MTSPs, was predominantly expressed in mouse oocytes and distributed at the spindle poles during meiosis in the present study. (cambridge.org)

It is developed from the primary oocyte by maturation. (wikipedia.org)
The succeeding phase of ootidogenesis occurs when the primary oocyte develops into an ootid. (wikipedia.org)

Mammalian oocytes are maintained in meiotic prophase arrest for a very long time-months in mice, years in humans. (wikipedia.org)
The multi-subunit shelterin complexes bind along mammalian telomeres, shielding the natural chromosome ends from engaging the DNA damage signaling and repair machinery [ 1 ]. (prolekarniky.cz)

However, as the oocyte grows, these proteins are synthesized, and meiotic arrest becomes dependent on cyclic AMP. (wikipedia.org)
Maintenance of meiotic arrest also depends on the presence of a multilayered complex of cells, known as a follicle, that surrounds the oocyte. (wikipedia.org)
In the oocyte, cyclic GMP prevents the breakdown of cyclic AMP by the phosphodiesterase PDE3, and thus maintains meiotic arrest. (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)
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)

Oogenesis consists of several sub-processes: oocytogenesis, ootidogenesis, and finally maturation to form an ovum (oogenesis proper). (wikipedia.org)
Diagram showing the reduction in number of the chromosomes in the process of maturation of the ovum . (wikipedia.org)

Intracytoplasmic sperm injection ( ICSI / ˈ ɪ k s i / IK -see ) is an in vitro fertilization (IVF) procedure in which a single sperm cell is injected directly into the cytoplasm of an egg . (wikipedia.org)
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)

Round spermatid injection (ROSI) is a technique of assisted reproduction whereby a round spermatid is injected into oocyte cytoplasm in order to achieve fertilization. (wikipedia.org)
Usage of melatonin during in vitro fertilization (IVF) procedures has been found to improve oocyte quality, survival, and fecundity. (jrhm.org)
SECM technique may be a valuable tool for accurately assessing the quality of embryos and thereby contribute to improving outcomes associated with assisted reproduction, including human in vitro fertilization. (bioone.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)
11 Among women undergoing in vitro fertilization-embryo transfer in the United States, deliveries per oocyte retrieved decreased from 36.9 percent among women under the age of 35 years to 20.5 percent among women between the ages of 38 and 40 years and to 10.7 percent among women between the ages of 41 and 42 years. (ldysinger.com)
To ascertain whether the Kunming (KM) mouse is an available model for age-related decline in female fertility in human or not, oocytes from young (6-8 weeks), middle-aged (9 months) and aged (12 months) female mice were compared with respect to number of oocytes, frequency of in-vitro maturation (IVM) and in-vitro fertilization (IVF), and meiotic chromosome segregation and alignment. (cambridge.org)

Thus, further experiments are required to determine the true dynamics of small follicle formation. (wikipedia.org)

The mean number of ovarian follicles, ovarian germinal vesicle oocytes and ovulated MII oocytes decreased significantly with maternal age. (cambridge.org)
Significant reduction of germinal vesicle (GV) and MII oocytes and significant increase of metaphase chromosome misalignment and premature chromatid segregation after meiotic maturation of oocytes, similar to human, presumably contribute to the decline in aged KM mice. (cambridge.org)
The germinal vesicle breakdown (GVBD) is a landmark event of oocyte maturation. (cambridge.org)
In our previous studies, we found that zona pellucida 3 (ZP3) was strongly concentrated in the nuclear region of germinal vesicle (GV) oocytes and interacted with aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) and lamin A to promote GVBD. (cambridge.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)

It mediates proper CHROMOSOME SEGREGATION and contractile ring function during CYTOKINESIS. (lookformedical.com)
Aurora kinases are found in all organisms in which their function has been conserved throughout evolution, namely the control of chromosome segregation. (lookformedical.com)

The endomitotic cycle (endomitosis) starts with a normal prophase (endoprophase), after which the chromosome contracts further (endometaphase), their sister chromatids separate from each other (endoanaphase) and decondense to assume the interphase nuclear structure, resulting in polyploid cells, with double the chromosome number (endopolyploidy) at the end of each cycle. (scielo.br)

This technique is used in order to prepare the gametes for the obtention of embryos that may be transferred to a maternal uterus. (wikipedia.org)
If all requirements for round spermatid selection and injection are successfully met, the injected oocytes develop to early embryos and can be transferred to the mother's uterus to produce pregnancy. (wikipedia.org)
and the development of embryos after in vitro fertilisation. (bvsalud.org)
In this paper, we describe a scanning electrochemical microscopy (SECM) technique that is a non-invasive and sensitive method for measuring oxygen consumption by individual embryos. (bioone.org)

This study may be an important supplement for the mechanism of oocyte meiotic resumption and provide new diagnostic targets and treatment clues for infertility patients with oocyte maturation disorder. (cambridge.org)

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 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)
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)
JNK2 was associated with the spindles especially the spindle poles and cytoplasmic microtubule organizing centers at prometaphase I, metaphase I, and metaphase II stages. (cambridge.org)

Injection of myc-tagged JNK2α1 mRNA into oocytes also revealed its localization on spindle poles. (cambridge.org)

AIPL1 was also proved to accumulate in the GV region of oocytes, and ZP3 deletion can significantly inhibit the aggregation of AIPL1 in the nuclear region. (cambridge.org)

Oogenesis starts with the process of developing primary oocytes, which occurs via the transformation of oogonia into primary oocytes, a process called oocytogenesis. (wikipedia.org)
Female infants have 6 to 7 million oocytes at 20 weeks of gestation, when progressive atresia occurs, resulting in 1 to 2 million oocytes at birth, approximately 25,000 at the age of 37 years, and 1000 at the age of 51 years, the average age of natural menopause in the United States. (ldysinger.com)

At puberty the number of oocytes decreases even more to reach about 60,000 to 80,000 per ovary, and only about 500 mature oocytes will be produced during a woman's life, the others will undergo atresia(degeneration). (wikipedia.org)
Further, melatonin and its receptors play a significant role in antioxidant defense mechanism of ovary for follicular growth and maturation. (jrhm.org)
In plants, polytene chromosomes have been observed in only a few species, and seemed to be restricted to ovary and immature seed tissues, e.g., in Phaseolus coccineus and P. vulgaris (Nagl, 1981), until relatively recently, when they were observed in the cells of the anther tapetum of Vigna unguiculata (Guerra and Carvalheira, 1994) and of some Phaseolus species (Carvalheira and Guerra, 1994). (scielo.br)

It is commonly believed that, when oocytogenesis is complete, no additional primary oocytes are created, in contrast to the male process of spermatogenesis, where gametocytes are continuously created. (wikipedia.org)

In cases of nonobstructive (secretory) azoospermia, on the other hand, testicular sperm production is blocked at different stages of the process of sperm formation (spermatogenesis). (wikipedia.org)

Additionally, the advancements in understanding the molecular cytoplasmic events occurring in oocytes, such as maternal mRNA degradation, posttranslational regulation, and organelle distribution associated with the quality of oocyte maturation, are reviewed. (bvsalud.org)

It has been hypothesized that in gonadal dysgenesis various deletions on the X chromosome cause such rapid atresia of oocytes 5 that few girls with this condition reach puberty with functioning ovaries. (ldysinger.com)

An aurora kinase that localizes to the CENTROSOME during MITOSIS and is involved in centrosome regulation and formation of the MITOTIC SPINDLE. (lookformedical.com)

This review focuses on the differential responses of cell types to ATZ toxicity, testicular effects of ATZ in both in vitro and in vivo models and chemopreventive strategies, so as to highlight the current state of the art on the toxicological outcomes of ATZ exposure in several experimental model systems. (frontiersin.org)
In vivo development was assessed after transfer of injected oocytes to the oviducts of recipient mares. (bioone.org)

The cyclic AMP is generated by the oocyte by adenylyl cyclase in the oocyte membrane. (wikipedia.org)
The granulosa cells produce a small molecule, cyclic GMP, that diffuses into the oocyte through the gap junctions. (wikipedia.org)

1985) described polytene chromosomes as giant chromosomes produced by changes in the mitotic cycle during the interphase stage. (scielo.br)

When in vitro experimental models are exposed to ATZ, they are faced with increased levels of reactive oxygen species (ROS), cytotoxicity and decreased growth rate at dosages that may vary with cell types. (frontiersin.org)
However, in this group, the use of the available techniques is controversial and should be considered experimental. (ldysinger.com)

Notably, mutations in the TPP1 OB-fold domain compromise telomerase-dependent telomere extension but not telomere end protection [ 18 , 21 ], indicating that TPP1 performs a role in telomerase regulation which is distinct from its contribution to chromosome end protection. (prolekarniky.cz)

Decline in the Number of Oocytes from Birth to Menopause. (ldysinger.com)

and the formation of glutathione conjugates in the aerial parts of the plant (Tasli et al. (frontiersin.org)
Polytene chromosomes are structures found in highly specialized tissues in some animal and plant species, which are amplified through successive cycles of endoreduplication, finally producing several copies of each chromosome. (scielo.br)
In this paper some aspects of the occurrence of plant polytenes will be summarized along with the structure and function of these chromosomes. (scielo.br)

Depending on the specific species, oocytes can remain arrested for extended periods of time, ranging from months to even years. (bvsalud.org)
In many species, only one oocyte is specified among a group of interconnected germline sister cells. (bvsalud.org)

The rate of IVM in oocytes from young mice (73.9%) was less significantly than that in oocytes from middle-aged and aged mice (86.1% and 84.4%, respectively). (cambridge.org)
Immunocytochemical analysis showed that ageing caused a significantly higher rate (49.3%) of chromosome misalignment than that (15.7%) of the young mice. (cambridge.org)

However, it is also possible that such genetic defects result in a smaller complement of oocytes during gonadal development. (ldysinger.com)

As atresia continues, both the number and quality of oocytes fall below a critical level, and the rate of aneuploidy increases - a finding that is related at least in part to problems of the meiotic spindle 15 , 16 resulting in nondisjunction. (ldysinger.com)

In the endoreduplication cycle, the chromatid number is duplicated, but they do not segregate, and after various endoreduplication cycles, larger and thicker chromosomes are produced, called polytenics. (scielo.br)

Any factor interfering with this process may lead to impaired oocyte maturation, which in turn affects female reproductive function. (bvsalud.org)
The progressive loss of oocytes from fetal life through menopause is a normal process. (ldysinger.com)
1 , 2 The mechanism underlying this process is poorly understood and involves multiple factors encoded by genes on the X chromosome, as well as on autosomes. (ldysinger.com)

[2] The microinjection procedure for ROSI also differs slightly from that of ICSI, since additional stimuli are needed to ensure proper oocyte activation after spermatid injection. (wikipedia.org)

The low maturation rate of oocytes is an important reason for female infertility and failure of assisted pregnancy. (cambridge.org)

In this study, we have identified TIN2-R282H, the most common DC-causing mutation in shelterin subunit TIN2, as a separation-of-function mutant which impairs telomerase recruitment to telomeres, but not chromosome end protection. (prolekarniky.cz)

In normal women, at approximately 37.5 years of age, an accelerated atresia of the oocytes begins 1 , 2 ( Figure 1 ). (ldysinger.com)

In terms of insemination, ICSI needs only one sperm cell per oocyte , while IVF needs 50,000-100,000. (wikipedia.org)

For this reason, they have been very important in elucidating chromosome fine structure and physiology, especially in diptera. (scielo.br)

This technique can be used to enable genetic fatherhood to some men who have no spermatozoa in the ejaculate (azoospermia) and in whom spermatozoa cannot be obtained surgically from the testicles. (wikipedia.org)

The TPP1/POT1 heterodimer also promotes telomerase processivity, as demonstrated by an in vitro direct telomerase activity assay [ 4 , 20 ]. (prolekarniky.cz)

Even though many technical aspects of ROSI are similar to those of ICSI, there are also significant differences between both techniques. (wikipedia.org)

1 The images in Panel B - which shows histologic specimens of oocytes (arrows) taken from patients at birth, at the age of 25 years, and at the age of 50 years - are adapted from Erickson 8 and are reprinted with the permission of the publisher. (ldysinger.com)

Knockdown of msps blocks the oocyte growth and causes gradual loss of oocyte determinants. (bvsalud.org)

The mouse Tzfp gene, mapped to chromosome 7 B2-B3, encodes a 465-amino acid transcription factor containing a conserved N-terminal BTB/POZ domain and three C-terminal PLZF-like C(2)H(2) zinc fingers. (lookformedical.com)

The adenylyl cyclase is kept active by a constitutively active G-protein-coupled receptor known as GPR3 and a G-protein, Gs, also present in the oocyte membrane. (wikipedia.org)

Anatomy14

Organisms2

Diseases3

Chemicals and Drugs6

Analytical, Diagnostic and Therapeutic Techniques and Equipment5

Phenomena and Processes16

Information Science2

Meiosis11

Primary oocyte2

Mammalian2

Meiotic arrest5

Ovum2

Intracytoplasmic sperm inj2

Fertilization6

Follicle1

Germinal vesicle4

Embryonic development1

Segregation2

Prophase1

Embryos4

Resumption1

Microtubule5

Poles1

Nuclear1

Occurs2

Ovary3

Oocytogenesis1

Spermatogenesis1

Maternal1

Puberty1

Mitosis1

Vivo2

Cyclic2

Mitotic1

Experimental2

Regulation1

Decline1

Plant3

Species2

Significantly2

Development1

Quality1

Cycles1

Process3

Injection1

Female1

Function1

Begins1

Cell1

Important1

Genetic1

Activity1

Significant1

Patients1

Growth1

Mouse1

Present1