Academic literature on the topic 'Growing oocyte'
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Journal articles on the topic "Growing oocyte"
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Lodde, Valentina, Rodrigo Garcia Barros, Priscila Chediek Dall’Acqua, Cecilia Dieci, Claude Robert, Alexandre Bastien, Marc-André Sirard, Federica Franciosi, and Alberto Maria Luciano. "Zinc supports transcription and improves meiotic competence of growing bovine oocytes." Reproduction 159, no. 6 (May 2020): 679–91. http://dx.doi.org/10.1530/rep-19-0398.
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In the last years, many studies focused on the understanding of the possible role of zinc in the control of mammalian oogenesis, mainly on oocyte maturation and fertilization. However, little is known about the role of zinc at earlier stages, when the growing oocyte is actively transcribing molecules that will regulate and sustain subsequent stages of oocyte and embryonic development. In this study, we used the bovine model to gain insights into the possible involvement of zinc in oocyte development. We first mined the EmbryoGENE transcriptomic dataset, which revealed that several zinc transporters and methallothionein are impacted by physiological conditions throughout the final phase of oocyte growth and differentiation. We then observed that zinc supplementation during in vitro culture of growing oocytes is beneficial to the acquisition of meiotic competence when subsequently subjected to standard in vitro maturation. Furthermore, we tested the hypothesis that zinc supplementation might support transcription in growing oocytes. This hypothesis was indirectly confirmed by the experimental evidence that the content of labile zinc in the oocyte decreases when a major drop in transcription occurs in vivo. Accordingly, we observed that zinc sequestration with a zinc chelator rapidly reduced global transcription in growing oocytes, which was reversed by zinc supplementation in the culture medium. Finally, zinc supplementation impacted the chromatin state by reducing the level of global DNA methylation, which is consistent with the increased transcription. In conclusion, our study suggests that altering zinc availability by culture-medium supplementation supports global transcription, ultimately enhancing meiotic competence.
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Guo, Jing, Teng Zhang, Yueshuai Guo, Tao Sun, Hui Li, Xiaoyun Zhang, Hong Yin, et al. "Oocyte stage-specific effects of MTOR determine granulosa cell fate and oocyte quality in mice." Proceedings of the National Academy of Sciences 115, no. 23 (May 21, 2018): E5326—E5333. http://dx.doi.org/10.1073/pnas.1800352115.
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MTOR (mechanistic target of rapamycin) is a widely recognized integrator of signals and pathways key for cellular metabolism, proliferation, and differentiation. Here we show that conditional knockout (cKO) of Mtor in either primordial or growing oocytes caused infertility but differentially affected oocyte quality, granulosa cell fate, and follicular development. cKO of Mtor in nongrowing primordial oocytes caused defective follicular development leading to progressive degeneration of oocytes and loss of granulosa cell identity coincident with the acquisition of immature Sertoli cell-like characteristics. Although Mtor was deleted at the primordial oocyte stage, DNA damage accumulated in oocytes during their later growth, and there was a marked alteration of the transcriptome in the few oocytes that achieved the fully grown stage. Although oocyte quality and fertility were also compromised when Mtor was deleted after oocytes had begun to grow, these occurred without overtly affecting folliculogenesis or the oocyte transcriptome. Nevertheless, there was a significant change in a cohort of proteins in mature oocytes. In particular, down-regulation of PRC1 (protein regulator of cytokinesis 1) impaired completion of the first meiotic division. Therefore, MTOR-dependent pathways in primordial or growing oocytes differentially affected downstream processes including follicular development, sex-specific identity of early granulosa cells, maintenance of oocyte genome integrity, oocyte gene expression, meiosis, and preimplantation developmental competence.
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Kere, Michel, Pan-Chen Liu, Yuh-Kun Chen, Pei-Chi Chao, Li-Kuang Tsai, Ting-Yu Yeh, Chawalit Siriboon, et al. "Ultrastructural Characterization of Porcine Growing and In Vitro Matured Oocytes." Animals 10, no. 4 (April 11, 2020): 664. http://dx.doi.org/10.3390/ani10040664.
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This study aimed to investigate ultrastructural changes of growing porcine oocytes and in vitro maturated oocytes. Light microscopy was used to characterize and localize the primordial, primary, secondary, and tertiary follicles. During oocyte growth and maturation, the morphology of mitochondria was roundish or ovoid in shape depending on the differentiation state, whereas their mean diameters oscillated between 0.5 and 0.7 µm, respectively, from primary and secondary follicles. Hooded mitochondria were found in the growing oocytes of the tertiary follicles. In addition to the pleomorphism of mitochondria, changes in the appearance of lipid droplets were also observed, along with the alignment of a single layer of cortical granules beneath the oolemma. In conclusion, our study is apparently the first report to portray morphological alterations of mitochondria that possess the hooded structure during the growth phase of porcine oocytes. The spatiotemporal and intrinsic changes during oogenesis/folliculogenesis are phenomena at the ultrastructural or subcellular level of porcine oocytes, highlighting an in-depth understanding of oocyte biology and impetus for future studies on practical mitochondrion replacement therapies for oocytes.
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Komorowski, Sebastian, Barbara Baranowska, and Marek Maleszewski. "CD9 protein appears on growing mouse oocytes at the time when they develop the ability to fuse with spermatozoa." Zygote 14, no. 2 (May 2006): 119–23. http://dx.doi.org/10.1017/s0967199405003497.
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SummaryCD9 is a member of the tetraspanin superfamily proteins and is the only protein on the mouse oocyte which is known to be indispensable in sperm–egg fusion. Here, using indirect immunofluorescence we show that CD9 appears on the oolemma during the early stages of the growth of the oocyte, when it measures 13–22 μm in diameter. When the oocyte reaches a diameter of 17–22 μm, the density of CD9 in its oolemma is similar to the density of this protein in the cell membrane of the fully grown secondary oocyte. The appearance of CD9 in growing oocytes correlates with the previously reported time of the acquisition of fusibility between the spermatozoon and the egg. Accordingly we propose that during oogenesis the development of the ability of the oolemma to fuse with sperm may be regulated by synthesis of CD9 by the oocyte.
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Stanislavovich, Tatiana, T. I. KUZMINA, and Aleksey Molchanov. "Assessment of the destructive processes of chromatin of granulosa cells and functional status of oocyte in bovine ovarian follicles." Agrarian Bulletin of the 191, no. 12 (December 9, 2019): 60–64. http://dx.doi.org/10.32417/1997-4868-2019-191-12-60-64.
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Abstract. Currently, there is the possibility of more detailed studies to the study of oocytes and somatic cells (granulosa cells). The possibility to develop successful models of maturation of female gametes defines the possibility to improve existing methods for the selection of donor eggs and the search for new donor eggs. Oocyte maturation in vivo occurs with the participation of structural follicle elements and follicular fluid [3, 4, 6]. Granulosa cells are widely used in bovine oocyte maturation systems and used in cloning and transgenesis technologies [8, 13]. Purpose of this study: to perform destructive changes granulosa cells in ovarian follicles of bovines (Ø 3–5 mm),which contain growing(ВСВ–) or completed the growth phase of oocytes (ВСВ+). Methods: Functional testing of oocytes wascarried out using the vital dye BCB (brillant cresyl blue – diamond crystal blue) [10]. Viability indices in granulosa cells isolated from follicles that contain oocyte s that grow or complete the growth phase were determined by flow cytometry. The result. It was found, that cellsof granulosa from cow follicles are characterized by different indicators of apoptosis levels depending on the status of oocytes (completed growth and growing) isolated from these follicles. The proportion of apoptotic granulosa cells in bovine follicles of containing oocytes that completed the growth phase, exceeded that in follicles containing growing oocytes by 11 % (29 % vs. 18 %, c:dP < 0.05). The scientific novelty: The data obtained using flow cytometry, allow us to evaluate the level of apoptosis in granulosa cells of bovine ovarian follicle as indicator of functional status of developing oocytes (growing or completed growth phases). This indicator can be used in prognosis of competencies for maturation of bovine oocytes.
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Sohel, M. M. H., D. Salilew-Wondim, M. Hölker, F. Rings, K. Schellander, and D. Tesfaye. "207 CIRCULATORY microRNA SIGNATURES IN FOLLICULAR FLUID IN RELATION TO THE GROWTH STATUS OF BOVINE OOCYTES." Reproduction, Fertility and Development 25, no. 1 (2013): 251. http://dx.doi.org/10.1071/rdv25n1ab207.
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Cell-to-cell communication within the follicle involves many signalling molecules, and this process is believed to be mediated by secretion and uptake of exosomes that contained several bioactive molecules including circulatory microRNAs (miRNA). The present study was conducted to investigate the circulating miRNA expression pattern in exosome and nonexosomal portion of follicular fluid (FF) in follicles with fully grown or growing oocytes. For this, the FF and cumulus–oocyte complexes (COC) were retrieved from 5- to 8-mm individual follicles from ovaries obtained from local abattoir. Then, the oocytes were subjected to brilliant cresyl blue (BCB) staining and classified as BCB+ (fully grown oocytes) and BCB– (growing oocytes). Accordingly, the corresponding FF was classified as BCB+ and BCB– based on their oocyte source. Following this, the exosomes were trapped from each FF categories using ExoQuick™ (SBI System Bioscience). Thus, total RNA was isolated from exosomal and nonexosomal portion of the FF using miRNeasy mini kit (Qiagen) and subjected to miRNA expression studies. The human miRCURY LNA™ Universal RT miRNA PCR array system (Exiqon) was used for miRNA expression profiling. Data analysis was performed using a comparative threshold cycle (ΔCT) method. The results revealed that 26 miRNAs were found to be differentially expressed (fold change ≥2 and P < 0.05) between the exosomal portion of FF from fully grown and growing oocyte groups. Among these, 17 miRNA including miR-608, miR-654-5p, miR-640, miR-582-5p, miR-449b, miR-155 were upregulated and 9 miRNA including miR-373, miR-526b*, miR-33a*, miR-30b, miR-29a* were downregulated in exosomal portion of FF of growing oocyte groups. The ingenuity pathway analysis of genes predicted to be targeted by those miRNAs were found to be involved in WNT/β catenine, purine metabolism, protein ubiquitination, and cAMP-mediated signalling pathways. Similarly, 36 miRNA were differentially expressed between the non-exosomal portion of FF of fully grown and growing oocytes. From those, 27 miRNA including let-7i*, miR-328, miR-223, miR-19b-1*, miR-423-5p, miR-29c, miR-659 were upregulated, whereas the expression level of 9 miRNA including miR-381, miR-18a*, miR-30e*, miR-934, and miR-302c was downregulated in the nonexosomal portion of FF of growing oocyte groups. In addition, the ingenuity pathway analysis indicated that the genes predicted to be targeted by these miRNA were found to be involved in NRF2-mediated oxidative stress response, tight junction signalling, and protein ubiquitination pathways. In conclusion, this study detected the presence of exosome or non-exosome-mediated circulation of miRNA in the bovine follicular fluid and oocyte growth-dependent variation of circulatory miRNA in the follicular environment.
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Kovo, Michal, Miri Kandli-Cohen, Miri Ben-Haim, Dalia Galiani, Dan W. Carr, and Nava Dekel. "An active protein kinase A (PKA) is involved in meiotic arrest of rat growing oocytes." Reproduction 132, no. 1 (July 2006): 33–43. http://dx.doi.org/10.1530/rep.1.00824.
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Reinitiation of meiosis in meiotically competent, fully grown mammalian oocytes is governed by a fall in intraoocyte cAMP concentrations and the subsequent inactivation of protein kinase A (PKA). A similar reduction in intraoocyte cAMP concentrations in growing, meiotically incompetent rat oocytes not leading to resumption of meiosis, questions the involvement of PKA in the regulation of meiosis at this early stage of oocyte development. We examined the possibility of whether PKA activity maintains growing oocytes in meiotic arrest and further explored the mode of activation of PKA under conditions of relatively low cAMP concentrations. Our experiment demonstrated that inactivation of PKA stimulates growing rat oocytes to resume meiosis, and elevates the activity of their maturation-promoting factor (MPF). We also found that the expressions of type I and type II regulatory subunits (RI and RII) of PKA are higher in growing and fully grown oocytes, respectively. In addition, we revealed that the common 1:1 ratio between the regulatory (R) and catalytic (C) subunits of PKA is apparently not abrogated and, in accordance PKA activity in growing oocyte - cell extract is fully dependent on cAMP. Finally, we identified in growing oocytes, the A kinase anchoring protein (AKAP) 140, which was previously depicted in fully grown oocytes. We conclude that an active PKA prevents growing oocytes from resuming meiosis. Our findings further suggest that relatively high abundance of the PKAI isoform and/or its subcellular compartmentalization, through interaction with AKAP140, could possibly account for the high basal PKA activity at relatively low intraoocyte cAMP concentrations.
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Taketsuru, Hiroaki, Yuji Hirao, Naoki Takenouchi, Kosuke Iga, and Takashi Miyano. "Effect of androstenedione on the growth and meiotic competence of bovine oocytes from early antral follicles." Zygote 20, no. 4 (November 9, 2011): 407–15. http://dx.doi.org/10.1017/s0967199411000268.
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SummaryMedium that contains 17β-estradiol has been reported to support in vitro growth of bovine oocytes, isolated from early antral follicles, until the final stage. The aim of this study was to determine the effects of androstenedione in medium on such growing bovine oocytes. Oocyte–granulosa cell complexes were collected from early antral follicles and cultured for 14 days in medium supplemented with 17β-estradiol (0, 10 and 100 ng/ml) or androstenedione (0, 10 and 100 ng/ml). The mean diameter of oocytes measured after seeding on the culture substrate was 96.9 μm (n = 191). Either steroid was necessary for maintainance of the organization of oocyte–granulosa cell complexes over the 14-day culture period. In the 17β-estradiol- or the androstenedione-supplemented medium about 80% or 65%, respectively, of viable oocytes were recovered. In both groups the increase in oocyte size was significant after 14 days. The in vitro grown oocytes were cultured for a further 22–24 h for oocyte maturation; 13% and 30% of oocytes grown in the 10 and 100 ng/ml 17β-estradiol-supplemented medium reached metaphase II, respectively; more than 64% of oocytes grown in the androstenedione-supplemented medium matured to metaphase II. These results show that androstenedione, as 17β-estradiol, can maintain the viability of bovine oocyte–granulosa cell complexes and support the growth of oocytes, and that androstenedione promotes the acquisition of oocyte meiotic competence efficiently at a low dose.
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Marteil, G., R. D'Inca, A. Pascal, N. Guitton, T. Midtun, A. Goksoyr, L. Richard-Parpaillon, and J. Z. Kubiak. "EP45 accumulates in growing Xenopus laevis oocytes and has oocyte-maturation-enhancing activity involved in oocyte quality." Journal of Cell Science 123, no. 10 (April 27, 2010): 1805–13. http://dx.doi.org/10.1242/jcs.063305.
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Senbon, Shoichiro, and Takashi Miyano. "Bovine oocytes in early antral follicles grow in serum-free media: effect of hypoxanthine on follicular morphology and oocyte growth." Zygote 10, no. 4 (October 31, 2002): 301–9. http://dx.doi.org/10.1017/s0967199402004033.
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Some culture systems have been shown to support oocyte growth in mice, although there has been little success in applying these systems to other species. In the present study, we compared three culture conditions for growing bovine oocytes and examined the effect of hypoxanthine on oocyte growth. In the first experiment, early antral follicles, 0.4-0.7 mm in diameter were collected, and oocyte-cumulus-granulosa cell complexes (OCGs) and oocyte-cumulus cell complexes (OCs) were dissected from the follicles. Follicles (Fs), OCGs and OCs were embedded in collagen gels and cultured in serum-supplemented medium for 16 days. In the Fs, OCGs and OCs cultured in hypoxanthine-free medium, 21%, 9% and 4% of the oocytes showed normal morphology, respectively, and hypoxanthine (4 mM) increased the percentages in all the groups (Fs, 37%; OCGs, 29%; OCs, 10%). In the second experiment, Fs were cultured in serum-free medium with or without hypoxanthine for 16 days. Histological examination demonstrated that hypoxanthine maintained the integrity of the follicular basement membrane. After a growth culture, 91% of the oocytes showed normal morphology, and 87% of the oocytes were at the germinal vesicle stage in serum-free, hypoxanthine-supplemented medium. The mean diameters of the oocytes were significantly larger (117.6 ± 5.7 mm) than they were in the other groups and than they had been before the culture (approximately 95 mm). After a subsequent maturation culture of the oocytes, 85% underwent germinal vesicle breakdown and 23% reached the second metaphase. These results demonstrate that growing bovine oocytes from early antral follicles grow efficiently in follicles cultured in serum-free, hypoxanthine-supplemented medium and acquire meiotic competence.
Dissertations / Theses on the topic "Growing oocyte"
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GARCIA, BARROS RODRIGO. "DEVELOPMENT OF NEW OOCYTE IN VITRO CULTURE STRATEGIES TO ENHANCE THE OUTCOME OF ASSISTED REPRODUCTIVE TECHNOLOGIES." Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/809746.
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Fertility preservation has received unprecedented attention nowadays. In addition to cryopreservation and re-implantation of embryos, oocytes, and ovarian tissue pieces, in vitro culture system for follicles/oocytes has been considered an alternative strategy for fertility preservation. Reproduction strategies based on the recovery of oocytes' population from antral follicles are unsatisfactory, and the success of this approach has not exceeded 35% of embryos produced in vitro for over 30 years. The possibility of accessing the reserve of smaller follicles (primordial, secondary, and up to the preantral stage) would amplify the number of gametes available for increasing reproductive potential. Furthermore, this would open enormous prospects for the rescue of fertility in various conditions in the human clinic and genetic rescue in animal breeding and biodiversity preservation programs. However, this would require developing protocols capable of growing immature oocytes to the stage in which they can be matured and fertilized in vitro.
Culture systems to achieve in vitro growth (IVG) of immature oocytes to maturity and subsequent fertilization in vitro (IVF) have been the subject of research for almost 40 years. Several systems that support the growth of later stages of follicle development from rodents have been developed, with some reporting the production of live young, but they are still at an experimental stage, and further research is required before the protocols could be clinically applied.
One of the significant limitations is identifying growth factors, hormones, and nutrients necessary for each specific follicle development stage. This evidence has led to hypothesize the development of culture systems consisting of a step-by-step approach, although no reliable protocols have been developed so far. The oocyte culture at the early stages of development represents an alternative to maximize the potential source of gamete used for fertility preservation. Several attempts have been made to recreate these conditions in vitro, but no reliable protocols have been developed to date. The lack of knowledge in the mechanisms involved in the early development of the oocyte and this passage from growing to fully grown stage be one of the most critical steps during oocyte development, these still represent the significant limiting factor for this technology.
The studies conducted during the doctorate program led to defining a physiological culture system that successfully differentiated growing bovine oocytes. This study used parameters predictive of oocyte differentiation to evaluate the current technique's efficiency and efficacy.
Based on previous observations from our laboratory, we initially hypothesized that zinc plays a role during the latest stages of oocyte growth and differentiation, particularly in controlling transcription during the final stage of oocyte growth. This first study demonstrated that zinc supplementation improves the meiotic competence of growing oocytes, affects the global transcription activity and the global DNA methylation. This information was used in the next part to better define a culture system for growing oocytes.
The subsequent study provided a 5-days protocol named L-IVCO (long in vitro culture of oocytes) to promote growing oocyte differentiation until the acquisition of meiotic and embryonic developmental competencies in a significantly higher proportion of the published protocols. This study demonstrated that a physiological medium could support a gradual transition of the oocyte from immature to mature stage, thus generating suitably quality blastocysts after fertilization.
In conclusion, our studies provide an improved protocol that can increase the source of fertilizable gametes in preservation programs and gives a prospective approach in human clinics, animal breeding programs, and salvage intervention of threatened species. Moreover, our studies defined a model to perform in-depth studies of the cellular and molecular processes that regulate the acquisition of meiotic and developmental competence during oocyte differentiation.
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Christmann, Leandro. "Acquisition of meiotic competence in growing porcine oocytes." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339451.
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Kagawa, Noriko. "Efficient production of matured oocytes and live pups from growing oocytes of adult female." Kyoto University, 2005. http://hdl.handle.net/2433/145027.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第11626号
農博第1482号
新制||農||906(附属図書館)
学位論文||H17||N4019(農学部図書室)
23269
UT51-2005-D375
京都大学大学院農学研究科応用生物科学専攻
(主査)教授 久米 新一, 教授 今井 裕, 教授 廣岡 博之
学位規則第4条第1項該当
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Li, Hou-kuan, and 李厚寬. "Expression of Bone Morphogenetic Protein-15 in Porcine Growing and Preovulatory Ovarian Cumulus-Oocyte-Complexs in vitro." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/97790366092485941574.
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碩士國立中山大學
生物醫學科學研究所
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The newly discovered oocyte-derived growth factor BMP15, like GDF9, is a member of the transforming growth factor-β (TGF-β) superfamily. To our knowledge, however, the expression and function of BMP15 in ovarian tissues has not yet been studied in the pig. We asked whether the relative abundance (RA) of BMP15 mRNA changes in oocytes and follicular cells during pre-ovulatory period or culture of cumulus-oocyte-complexs (COCs) in vitro. Denuded oocytes, cumulus cells and COCs were isolated from growing and pre-ovulatory follicles. Total RNA was extracted from the cells, and reverse transcriptase polymerase chain (RT-PCR) was carried out using specific oligo-nucleotide primers. Expansion of COCs was firstly observed at 18 h, when this period we found BMP15 mRNA expression obviously. But when we culture of denuded oocytes instead of COCs, BMP15 mRNA didn’t express throughout the period. We also detected GDF9 and BMP15 mRNA in pig embryonic stage and in differentiation stage of pig stem cell. GDF9 mRNA level continued to express after fertilization, but BMP15 mRNA didn’t appear. We also added BMP15 antibody against Expanding of COCs. The present results support the concept that BMP15 is a key mediator of oocyte-enabled cumulus expansion in pig.
Books on the topic "Growing oocyte"
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Paul Alexandre.* De Sousa. Protein synthesis in the fully grown oocytes and unactivated and activated eggs of "Xenopus laevis". 1989.
Find full textBook chapters on the topic "Growing oocyte"
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Hoai, L. T., N. X. Yen, L. K. Thoai, N. Van Thuan, and H.-T. Bui. "Improve the Meiotic Competence of Growing Porcine Oocytes from Preantral Follicle." In 6th International Conference on the Development of Biomedical Engineering in Vietnam (BME6), 859–63. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-4361-1_146.
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Ebner, Thomas. "Artificial Oocyte Activation." In Advances in Assisted Reproduction Technologies, 143–52. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815051667122050008.
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Against all expectations, the presence of a carefully selected normal spermatozoon does not guarantee oocyte activation/fertilization. In contrast, some ICSI cycles will have to face no or low fertilization in several consecutive cycles. Both sperm- and oocyte-derived problems may account for such a dilemma. In case of physiological activation problems, any artificial increase in ooplasmic calcium could rescue the fertilization process. Such approaches are summarized under the term artificial oocyte activation (AOA). AOA can be achieved by modified ICSI techniques, piezoelectrical manipulation, or chemical stimuli. Amongst these approaches, the latter is the currently most accepted one in IVF laboratories around the world and particularly the Ca2+-ionophores ionomycin and calcimycin are the most extensively studied agents. Recently, a ready-to-use ionophore (A23187) has been introduced which is CE-marked and as such will assist in the standardization of AOA techniques. There is growing evidence that for proper indications usage of AOA can be considered quite safe. This conclusion is based on studies on morphokinetics, chromosome segregation, and gene expression. More importantly, available neonatal and neurodevelopmental data are reassuring. However, since artificial oocyte activation rarely results in physiological Ca2+ oscillations and is not beneficial for all patients with a suspected activation deficiency these techniques should not be used without profound indication.
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Bozdag, Gurkan, Baris Ata, and Engin Türkgeldi. "Menstrual Cycle and Ovulation." In Oxford Textbook of Endocrinology and Diabetes 3e, edited by John A. H. Wass, Wiebke Arlt, and Robert K. Semple, 1260–65. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780198870197.003.0152.
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Understanding the physiology of follicular development is important in order to extrapolate the preclinical data to the clinical side. In this context, there has been an increasing effort to figure out the autocrine/paracrine signalling and microenvironment that will determine the fate of a follicle. The processes of atresia or further development to later stages reaching to a dominant follicle appear to be regulated by highly complicated system that consists oocyte and granulosa cell derived factors, peptides, cytokines, and sex steroids. Additionally, recent research on the menstrual cycle that yields the presence of more than one wave of follicular cohort growing within a single period will undoubtedly implicate our perception on reproductive function, hormonal contraception, and ovarian stimulation during an assisted reproduction treatment. This chapter reviews the current knowledge that reflects the timetable of a follicle throughout the early ages to the formation of dominant follicle and corresponding endometrial changes.
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Kinoh, H., T. Shimizu, M. Yamaguchi, and N. Suzuki. "Appearance of an egg jelly molecule, fucose sulfate glycoconjugate, in the extracellular matrix of the growing oocyte of the sea urchin Hemicentrotus pulcherrimus." In Biology of Echinodermata, 362. CRC Press, 2020. http://dx.doi.org/10.1201/9781003077565-90.
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Nyika, Joan Mwihaki. "Climate Change on Fertility and Reproductive Processes of Female Livestock." In Research Anthology on Environmental and Societal Impacts of Climate Change, 1278–92. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-3686-8.ch062.
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The effects of climate change continues to be a growing modern-day challenge. Climate change-induced heat stress disrupts reproductive and fertility systems in livestock. In males, it modifies the physiology of the spermatogenic cycle resulting to poor quality semen and high prevalence of secondary sperm defects. In female livestock, heat stress decreases the production of gonadotrophins, results to hormonal imbalance, decreases the quality of oocytes, and lengthens the oestrous period leading to infertility. These effects can be reversed through genetic modifications, nutritive supplementation, physical cooling mechanisms, and hormonal therapies. The successful implementation of the ameliorative strategies is pegged on improved research and their combined administration. Ultimately, climate change mitigation and adaptation are indispensable to overcome fertility problems in livestock among other environmental effects of the climate variations.
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Nyika, Joan Mwihaki. "Climate Change on Fertility and Reproductive Processes of Female Livestock." In Climate Change and Its Impact on Fertility, 263–77. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4480-8.ch013.
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The effects of climate change continues to be a growing modern-day challenge. Climate change-induced heat stress disrupts reproductive and fertility systems in livestock. In males, it modifies the physiology of the spermatogenic cycle resulting to poor quality semen and high prevalence of secondary sperm defects. In female livestock, heat stress decreases the production of gonadotrophins, results to hormonal imbalance, decreases the quality of oocytes, and lengthens the oestrous period leading to infertility. These effects can be reversed through genetic modifications, nutritive supplementation, physical cooling mechanisms, and hormonal therapies. The successful implementation of the ameliorative strategies is pegged on improved research and their combined administration. Ultimately, climate change mitigation and adaptation are indispensable to overcome fertility problems in livestock among other environmental effects of the climate variations.
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Nyika, Joan Mwihaki. "Climate Change on Fertility and Reproductive Processes of Female Livestock." In Climate Change and Its Impact on Fertility, 263–77. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4480-8.ch013.
Full textAbstract:
The effects of climate change continues to be a growing modern-day challenge. Climate change-induced heat stress disrupts reproductive and fertility systems in livestock. In males, it modifies the physiology of the spermatogenic cycle resulting to poor quality semen and high prevalence of secondary sperm defects. In female livestock, heat stress decreases the production of gonadotrophins, results to hormonal imbalance, decreases the quality of oocytes, and lengthens the oestrous period leading to infertility. These effects can be reversed through genetic modifications, nutritive supplementation, physical cooling mechanisms, and hormonal therapies. The successful implementation of the ameliorative strategies is pegged on improved research and their combined administration. Ultimately, climate change mitigation and adaptation are indispensable to overcome fertility problems in livestock among other environmental effects of the climate variations.