Relevant bibliographies by topics / Oocytes competence

Academic literature on the topic 'Oocytes competence'

Author: Grafiati
Published: 9 March 2023
Last updated: 10 March 2023

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Journal articles on the topic "Oocytes competence"

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Walker, Bailey N., and Fernando H. Biase. "The blueprint of RNA storages relative to oocyte developmental competence in cattle (Bos taurus)." Biology of Reproduction 102, no. 4 (January 26, 2020): 784–94. http://dx.doi.org/10.1093/biolre/ioaa015.

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Abstract From the time oocytes leave quiescence, there are constant microenvironmental influences contributing to development, thus acquiring developmental competence is not a simple, linear phenomenon. During folliculogenesis, oocytes experience many morphological and cytological changes that contribute toward the acquisition of developmental competence, a process defined by an oocyte’s ability to progress through folliculogenesis, be fertilized, undergo cleavage, and develop into an embryo. Many factors, such as ovarian follicle size, cow age, and the morphology of the cumulus–oocyte complex, have been extensively investigated to understand this process. In parallel to aiding in the understanding of oocyte biology, these features have been used to characterize an oocyte’s ability to achieve competence. In addition, oocytes undergo intense gene transcription and protein translation to accumulate the maternal stores. When the oocyte is fully grown, most genes are transcriptionally inactive, and the chromatin is densely compacted. More recently, RNA profiling has been used to further define the transcriptional parameters that are associated with oocyte development. Here, focusing on cattle, we provide an overview of the experimental models commonly used to understand the underlying biology related to oocyte developmental competence. We compiled public data and showed that cattle oocytes can express over 15 000 protein-coding genes, suggesting a complex transcriptome landscape. Surprisingly, less than 2% of the expressed genes have been linked to developmental competence. The identification of the gene products that contribute to oocyte development, and understanding their biological function, are a vital component of our quest toward defining oocyte developmental competence at the molecular level.
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Ritter, Lesley J., Satoshi Sugimura, and Robert B. Gilchrist. "Oocyte Induction of EGF Responsiveness in Somatic Cells Is Associated With the Acquisition of Porcine Oocyte Developmental Competence." Endocrinology 156, no. 6 (June 1, 2015): 2299–312. http://dx.doi.org/10.1210/en.2014-1884.

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Abstract Oocytes progressively acquire the competence to support embryo development as oogenesis proceeds with ovarian folliculogenesis. The objectives of this study were to investigate oocyte-secreted factor (OSF) participation in the development of somatic cell epidermal growth factor (EGF) responsiveness associated with oocyte developmental competence. A well-established porcine model was employed using oocytes from small (<4 mm) vs medium sized (>4 mm) antral follicles, representing low vs moderate developmental competence, respectively. Cumulus-oocyte complexes (COCs) were treated in vitro with inducers of oocyte maturation, and cumulus cell functions and oocyte developmental competence were assessed. COCs from small follicles responded to FSH but, unlike COCs from larger follicles, were incapable of responding to EGF family growth factors known to mediate oocyte maturation in vivo, exhibiting perturbed cumulus expansion and expression of associated transcripts (HAS2 and TNFAIP6). Low and moderate competence COCs expressed equivalent levels of EGF receptor (EGFR) mRNA; however, the former had less total EGFR protein leading to failed activation of phospho-EGFR and phospho-ERK1/2, despite equivalent total ERK1/2 protein levels. Native OSFs from moderate, but not from low, competence oocytes established EGF responsiveness in low competence COCs. Four candidate recombinant OSFs failed to mimic the actions of native OSFs in regulating cumulus expansion. Treatment with OSFs and EGF enhanced oocyte competence but only of the low competence COCs. These data suggest that developmental acquisition by the oocyte of capacity to regulate EGF responsiveness in the oocyte's somatic cells is a major milestone in the oocyte's developmental program and contributes to coordinated oocyte and somatic cell development.
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Pedersen, Hanne Skovsgaard, Peter Løvendahl, Knud Larsen, Lone Bruhn Madsen, and Henrik Callesen. "Porcine oocyte mtDNA copy number is high or low depending on the donor." Zygote 24, no. 4 (December 18, 2015): 617–23. http://dx.doi.org/10.1017/s0967199415000611.

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SummaryOocyte capacity is relevant in understanding decreasing female fertility and in the use of assisted reproductive technologies in human and farm animals. Mitochondria are important to the development of a functionally good oocyte and the oocyte mtDNA copy number has been introduced as a useful parameter for prediction of oocyte competence. The aim of this study was to investigate: (i) if the oocyte donor has an influence on its oocyte's mtDNA copy number; and (ii) the relation between oocyte size and mtDNA copy number using pre- and postpubertal pig oocytes. Cumulus–oocyte complexes were collected from individual donor pigs. The oocytes were allocated into different size-groups, snap-frozen and single-oocyte mtDNA copy number was estimated by quantitative real-time PCR using the genes ND1 and COX1. Results showed that mean mtDNA copy number in oocytes from any individual donor could be categorized as either ‘high’ (≥100,000) or ‘low’ (<100,000) with no difference in threshold between pre- and postpubertal oocytes. No linear correlation was detected between oocyte size and mtDNA copy number within pre- and postpubertal oocytes. This study demonstrates the importance of the oocyte donor in relation to oocyte mtDNA copy number, irrespectively of the donor's puberty status and the oocyte's growth stage. Observations from this study facilitate both further investigations of the importance of mtDNA copy number and the unravelling of relations between different mitochondrial parameters and oocyte competence.
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Petr, J., E. Chmelíková, K. Kheilová, and F. Jílek. "Histone deacetylase inhibition improves meiotic competence but not developmental competence in growing pig oocytes." Zygote 17, no. 4 (May 22, 2009): 307–14. http://dx.doi.org/10.1017/s0967199409005437.

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SummaryIn fully grown pig oocytes, meiotic maturation in vitro is retarded by inhibition of histone deacetylases by trichostatin A (TSA). In growing oocytes with partial meiotic competence, culture with TSA has no significant effect on the meiotic maturation. Growing oocytes treated with TSA mature mainly to metaphase I. The ratio of oocytes that mature to metaphase II is very limited. After transient exposure to TSA, the maturation of growing oocytes with partial meiotic competence takes a different course. When these oocytes are first cultured in a TSA-free medium, then cultured for another 24 h with 100 nM TSA and finally again in a TSA-free medium for 24 h, the ratio of oocytes that mature to metaphase II significantly increases reaching 59%. When oocytes were cultured for the same length of time without transient exposure to TSA, only 19% matured to metaphase II. Those oocytes that matured to metaphase II after transient exposure to TSA were successfully activated using calcium ionophore. However, the subsequent cleavage was very limited. We can conclude that transient exposure of growing pig oocytes with partial meiotic competence to TSA increases oocyte meiotic competence, but it does not enhance developmental competence after parthenogenetic activation.
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Rodriguez, Karina F., and Charlotte E. Farin. "Gene transcription and regulation of oocyte maturation." Reproduction, Fertility and Development 16, no. 2 (2004): 55. http://dx.doi.org/10.1071/rd03078.

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The developmental potential of an embryo is dependent on the developmental potential of the oocyte from which it originates. The process of oocyte maturation is critical for the efficient application of biotechnologies such as in vitro embryo production and mammalian cloning. However, the overall efficiency of in vitro maturation remains low because oocytes matured in vitro have a lower developmental competence than oocytes matured in vivo. Furthermore, oocytes that have been exposed to gonadotropins have greater developmental competence than oocytes matured in the absence of gonadotropins. By understanding the molecular mechanisms underlying gonadotropin-induced maturation, improvement in oocyte maturation technologies may be expected as procedures to manipulate specific factors involved in signalling for resumption of meiosis are identified. The present review will focus on transcriptional mechanisms underlying the maturation of mammalian oocytes in vitro, as well as on the acquisition of oocyte developmental competence. In addition, a working model for the transcriptional control of mammalian oocyte maturation is proposed.
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Feng, Wei Guo, and Zhi Fang Pan. "The Effect of Granulosa Cells Apoptosis on the Cumulus Expansion and the Developmental Competence of Bovine Oocytes." Advanced Materials Research 997 (August 2014): 251–54. http://dx.doi.org/10.4028/www.scientific.net/amr.997.251.

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In this study, we used the well in the well (WIW) culture system to study the effect of granulosa cells apoptosis on the cumulus expansion and the developmental competence of bovine oocytes. Results: The apoptosis of granulosa cells affect the cumulus expansion of bovine oocytes significantly. Especially when the percentage of granulosa cells apoptosis exceed 40%, the cumulus expansion was worse. The cumulus expansion affect the oocyte developmental competence of bovine oocytes significantly. The developmental competence of bovine oocyte increases with the increasing of cumulus expansion.
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Herrick, Jason R. "Reversible meiotic arrest in feline oocytes." Reproduction, Fertility and Development 26, no. 2 (2014): 258. http://dx.doi.org/10.1071/rd12341.

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Increasing intracellular concentrations of cyclic adenosine monophosphate (cAMP) within the cumulus–oocyte complex (COC) inhibits or delays spontaneous oocyte maturation and improves the developmental competence of the oocyte in many species, but information for carnivores is limited. The objectives of the present study were to describe the effects of isobutyl methylxanthine (IBMX), which decreases cAMP degradation, and forskolin, which increases cAMP production, on spontaneous and induced maturation (by equine chorionic gonadotrophin (eCG) and epidermal growth factor (EGF)) of feline oocytes and to evaluate the reversibility of IBMX-induced arrest by measuring the resumption of meiosis and embryonic development following IVF. IBMX decreased (P < 0.05) the incidence of spontaneous (6.7% vs 42.0%, metaphase II (MII)) and induced (5.6% vs 66.1% MII) maturation after 24 h of culture. In contrast, forskolin stimulated meiosis (81.7% MII; P < 0.05). Following 12 h of culture with IBMX and an additional 24 h with eCG and EGF in the absence of IBMX, the proportions of oocytes reaching MII (66.1%), cleaving (79.9%) and developing to the blastocyst stage (15.3%) were similar (P > 0.05) to oocytes cultured continuously with eCG and EGF (70.2%, 83.0% and 18.1%, respectively). These results demonstrate that IBMX reversibly inhibits both spontaneous and eCG+EGF-induced meiosis in feline oocytes without compromising the oocyte’s developmental competence.
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Pedersen, Hanne Skovsgaard, Henrik Callesen, Peter Løvendahl, Fenghua Chen, Jens Randel Nyengaard, Nanett Kvist Nikolaisen, Peter Holm, and Poul Hyttel. "Ultrastructure and mitochondrial numbers in pre- and postpubertal pig oocytes." Reproduction, Fertility and Development 28, no. 5 (2016): 586. http://dx.doi.org/10.1071/rd14220.

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Prepubertal pig oocytes are associated with lower developmental competence. The aim of this experiment was to conduct an exhaustive survey of oocyte ultrastructure and to use a design-unbiased stereological approach to quantify the numerical density and total number of mitochondria in oocytes with different diameters from pre- and postpubertal pigs. The ultrastructure of smaller prepubertal immature oocytes indicated active cells in close contact with cumulus cells. The postpubertal oocytes were more quiescent cell types. The small prepubertal oocytes had a lower total mitochondrial number, but no differences were observed in mitochondrial densities between groups. Mature postpubertal oocytes adhered to the following characteristics: presence of metaphase II, lack of contact between cumulus cells and oocyte, absence of rough endoplasmic reticulum and Golgi complexes, peripheral location of cortical granules and central localisation of mitochondria, vesicles and lipid droplets. Prepubertal oocytes displayed more variation. The ultrastructure of large pre- and postpubertal oocytes was compatible with higher developmental competence, whereas that of smaller prepubertal oocytes could explain their reduced capacity. The higher number of mitochondria in large pre- and postpubertal oocytes could have an influence on oocyte competence, by increasing the pool of mitochondria available for early embryonic development.
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Patel, Osman V., Anilkumar Bettegowda, James J. Ireland, Paul M. Coussens, Patrick Lonergan, and George W. Smith. "Functional genomics studies of oocyte competence: evidence that reduced transcript abundance for follistatin is associated with poor developmental competence of bovine oocytes." Reproduction 133, no. 1 (January 2007): 95–106. http://dx.doi.org/10.1530/rep.1.01123.

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Poor oocyte competence contributes to infertility in humans and livestock species. The molecular characteristics of such oocytes are generally unknown. Objectives of the present studies were to identify differences in RNA transcript abundance in oocytes and early embryos associated with reduced oocyte competence and development to the blastocyst stage. Microarray experiments were conducted using RNA isolated from germinal vesicle stage oocytes collected from adult versus prepubertal animals (model of poor oocyte competence). A total of 193 genes displaying greater mRNA abundance in adult oocytes and 223 genes displaying greater mRNA abundance in prepubertal oocytes were detected. Subsequent gene ontology analysis of microarray data revealed significant overrepresentation of transcripts encoding for genes in hormone secretion classification within adult oocytes and such genes were selected for further analysis. Real-time PCR experiments revealed greater abundance of mRNA for βA and βB subunits of inhibin/activin and follistatin, but not the α subunit in germinal vesicle stage oocytes collected from adult versus prepubertal animals. Cumulus cell follistatin and βB subunit mRNA abundance were similar in samples collected from prepubertal versus adult animals. A positive association between time of first cleavage (oocyte competence) and follistatin mRNA abundance was noted. Follistatin, βB, and α subunit mRNAs were temporally regulated during early bovine embryogenesis and peaked at the 16-cell stage. Collectively, results demonstrate a positive association of follistatin mRNA abundance with oocyte competence in two distinct models and dynamic regulation of follistatin, βB, and α subunit mRNAs in early embryos after initiation of transcription from the embryonic genome.
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Cai, L., E. Kim, S. U. Hwang, J. D. Yoon, Y. Jeon, E. Lee, and S. H. Hyun. "156 EFFECTS OF MORPHOLOGY TYPE OF POLAR BODY ON PORCINE OOCYTE QUALITY AND DEVELOPMENTAL POTENTIAL AFTER IN VITRO FERTILIZATION." Reproduction, Fertility and Development 26, no. 1 (2014): 192. http://dx.doi.org/10.1071/rdv26n1ab156.

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Evaluation of morphology of first polar body (1st PB) could be a method for the oocyte's quality and developmental competence. The developmental potential of oocyte with fragmented PB after in vitro maturation (IVM) is a controversial issue. The aim of this study is to investigate the effects of PB morphology type on oocyte quality and developmental competence after IVF. Porcine ovaries were obtained from prepubertal gilts at a local slaughterhouse and transported to the laboratory within 2 h in physiological saline supplemented with 100 IU mL–1 penicillin G and 100 mg mL–1 streptomycin sulfate. The cumulus–oocyte complexes (COC) were aspirated using an 18-gauge needle attached to a 10-mL disposable syringe from superficial follicles 3 to 6 mm in diameter followed by IVM. After IVM, oocytes were classified into 3 types as follows, oocytes with normal PB (A type), oocytes with a little of fragmented PB (B type), and oocytes with separated 2 PBs (C type), respectively. As classification of PB types, we analysed the distribution ratio of each PB type after IVM, and then performed IVF for analysis of fertilization rate and developmental potential. The ratio of oocyte with A type (73%) was significantly (P < 0.05) higher than that of B type (24.5%) or C type (2.5%) after IVM. Only mature oocytes were selected from A and B type and were subjected to IVF because of a small number of oocytes with C type. In the IVF experiment, the efficiency of monospermy and fertilization were significantly higher in oocytes of A type (46.7%) than those of type B (20.0%). The cleavage rate of oocytes with A type (63.9%) was significantly (P < 0.05) higher than the oocytes with B type (43.8%). Embryonic developmental competence to the blastocyst stage after IVF was significantly (P < 0.05) higher in the A-type oocytes (26.3%) than in the B-type oocytes (16.9%). The levels of glutathione and reactive oxygen species were not affected by the morphological classification of the PB. In summary, these results suggest that polar body morphology could be a marker of oocyte quality after IVM. We are currently studying gene expression of each oocytes and blastocysts. This work was supported, in part, by a grant from the Next-Generation BioGreen 21 Program (No. PJ00956901), Rural Development Administration, and the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2012R1A1A4A01004885, NRF-2013R1A2A2A04008751), Republic of Korea.
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Dissertations / Theses on the topic "Oocytes competence"

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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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Zhu, Jie. "Pig oocyte activation and developmental competence of parthenogenetically activated oocytes : in vitro and in vivo studies." Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/27741.

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In somatic cell nuclear transfer in mammals, to clone a piglet is still a big challenge. Although many factors could contribute to the low success rate, such as quality of donor and recipient cells, types of donor cell including sources of animal breeds and tissues, number of passages and culture conditions, timing of cell cycle, procedures of nuclear transfer, techniques and embryos transfer, one of the factors is believed to be poor oocyte activation, especially in pig nuclear transfer. Therefore studies presented in this thesis aimed at the establishment of an in vitro culture system for pig oocyte maturation and embryo culture, based on this system an electrical activation protocol for pig oocytes was optimized and also tested by monitoring in vivo development of activated pig oocytes. Finally, the protocol was used for activating pig embryos reconstructed by transfer of somatic cells into enucleated ovulated oocytes and for production of pig parthenotes to maintain pregnancies of cloned pig embryos, which resulted in the birth of a cloned male piglet. The thesis comprises a total of 6 chapters. In addition to the review of literature (Chapter 1), general materials and methods (Chapter 2) and general discussion (Chapter 6), in Chapter 3 and 4, the studies focused on optimizing electrical parameters on pig oocyte activation and investigating the effects of activation conditions including temperature, activation medium, and concentrations of Ca2+ and Mg2+ in activation medium and diploidization of activated oocytes. These experiments were carried out in vitro, whereas experiments in Chapter 5 were conducted in vivo to assess the in vivo developmental competence of in vitro matured (IVM) pig oocytes activated by the improved activation protocol.
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Zarate-Garcia, Larissa. "Understanding the meiotic competence of oocytes derived from oogonial stem cells." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/413809/.

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This thesis investigates whether Oogonial Stem Cells (OSCs) exist and can be isolated from the adult mouse ovary. It also examines their ability to differentiate into oocyte-like cells in vitro. Transmembrane domains in the DEAD-box polypeptide 4 (DDX4) – the germline marker used in this antibody-based isolation – are examined using in silico protein modelling. The specificity of this antibody to DDX4 is tested in male and female germline cells. It is shown that the DDX4 antibody may have some specificity for DDX4, but the existence of a surface-bound DDX4 is unlikely. OSC-like cells can be isolated from the ovary using the DDX4 antibody by Fluorescence-Activated Cell Sorting (FACS). However, gene expression analysis and protein immunofluorescence show that these cells do not initially express DDX4 or possess germline identity. Despite this, they acquire some pre-meiotic and oocyte-specific markers in culture, including DDX4. Critically, the cells never express meiosis-specific markers even in the presence of meiotic enhancers BMP4 and retinoic acid. It is unlikely that these ovarian cells are being sorted by means of a cell surface DDX4 expression, because another antibody to a larger DDX4 epitope fails to detect DDX4 in isolated cells. These findings highlight that freshly isolated OSCs are not germ stem cells, and are not being isolated by their DDX4 expression, but instead may reflect an artefact of the antibody used or procedure adopted. Altogether this work offers support to the established dogma that the adult ovary is populated at birth by a fixed number of oocytes, and that adult de novo production is a rare or insignificant event.
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Koeman, Jennifer. "Developmental competence of prepubertal and adult goat oocytes cultured in semi-defined media." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33417.

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In vitro production of embryos from oocytes recovered by laparoscopic oocyte pick-up (LOPU) offers great potential for the propagation of genetically valuable animals. In turn, the application of these techniques to prepubertal animals presents added benefits in that prepubertal animals may supply a greater number of oocytes than adult animals. The aim of the present study was to evaluate the developmental competence of prepubertal and adult goat oocytes cultured in semi-defined media. The follicular response and recovery of oocytes via LOPU from hormonally stimulated prepubertal and adult goats were also assessed.
Oocytes were collected over a 15-wk period from prepubertal goats, ranging in age between 3--7 mo, and adult controls, ranging in age between 2--4 yr, randomly divided into 10 collection groups. Oocytes from six of the ten collections were matured for 26 h. Four collections were not completed due to technical difficulties. Following insemination, zygotes were cultured for 4 d in G1.2 followed by 4 d in G2.2. Morulae and blastocysts were scored via light microscopy on Days 7 and 9, followed by fluorescent staining on Day 9 for cell counts. (Abstract shortened by UMI.)
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Demond, Hannah [Verfasser], and Bernhard [Akademischer Betreuer] Horsthemke. "Effects of preovulatory aging on the developmental competence of mouse oocytes / Hannah Demond. Betreuer: Bernhard Horsthemke." Duisburg, 2016. http://d-nb.info/1102896969/34.

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Held, Eva [Verfasser]. "Morphological reflectors and molecular predictors of preimplantation developmental competence of bovine oocytes and embryos / Eva Held." Bonn : Universitäts- und Landesbibliothek Bonn, 2013. http://d-nb.info/1043056831/34.

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Silva, Celia Costa Gomes da. "Effects of inhibin, activin and follistatin on the developmental competence of in vitro matured bovine oocytes." Thesis, University of Reading, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266146.

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CONSIGLIO, A. LANGE. "Equine compact cumulus oocytes for in vitro reproductive technologies : meiotic competence improvement and relationship with nutritional status and puberal development." Doctoral thesis, Università degli Studi di Milano, 2008. http://hdl.handle.net/2434/54758.

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The aim of this thesis was to investigate cellular processes critical to equine maturation, fertilization and embryo development in vitro. Equine compact cumulus oocytes (CCO) in vitro have low competence, so we evaluated the efficacy of a pre-maturation step in improving the coordination of cytoplasmic and nuclear maturation of CCO by the addition of Roscovitine and our results showed partial improving of the competence of these oocytes. Moreover, we carried out a study to examine the immunolocalization of leptin (Ob) and leptin receptor (Ob-R) in CCO recovered from fillies and from mares of light vs heavy body weight breeds after slaughtering and to further improve the maturation rate of CCO we supplemented the maturation medium with leptin and investigated its effect in expanded and compact cumulus oocytes on maturation, fertilization and embryo cleavage rates after intra cytoplasmic sperm injection (ICSI). The results supported the hypothesis that, in the horse, leptin is differently localized during oocyte IVM showing different immunoreaction intensity related either to the horse breed or to the reproductive puberal development. In vitro, the presence of leptin during oocyte maturation improves the progression of meiosis and the rate of fertilization after ICSI but, by contrast to other species, in our horse model no differences were detected in the subsequent development rates of embryos: probably species-differences exist in embryos with regard to sensitivity to leptin.
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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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Assidi, Mourad. "Oocyte competence and cumulus cells gene expression." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27679/27679.pdf.

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Books on the topic "Oocytes competence"

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Beyond second opinions: Making choices about fertility treatment. Berkeley: University of California Press, 1998.

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Book chapters on the topic "Oocytes competence"

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Homer, Hayden. "Evaluating Spindle Assembly Checkpoint Competence in Mouse Oocytes Using Immunoblotting." In Cell Cycle Checkpoints, 33–45. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-61779-273-1_4.

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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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Sirard, Marc-André, and Mourad Assidi. "Screening for Oocyte Competence." In Oocyte Physiology and Development in Domestic Animals, 191–206. Oxford, UK: Wiley-Blackwell, 2013. http://dx.doi.org/10.1002/9781118538074.ch10.

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Eichenlaub-Ritter, Ursula, and Fengyun Sun. "Maternal Age and Oocyte Competence." In Essential IVF, 201–30. Boston, MA: Springer US, 2004. http://dx.doi.org/10.1007/978-1-4419-8955-0_8.

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Thuy-Van, N. T., P. T. Duy, T. B. An, N. Van Thuan, and H. T. Bui. "Effect of Dibutyryl-Camp (Dbc-AMP) and Follicle Stimulation Hormone (FSH) on Meiotic Competence of Porcine Oocytes During In Vitro Maturation and Fertilization." In 6th International Conference on the Development of Biomedical Engineering in Vietnam (BME6), 889–93. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-4361-1_151.

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Cavilla, Jennifer, and Geraldine Hartshorne. "Oocyte Competence and In Vitro Maturation." In Essential IVF, 241–71. Boston, MA: Springer US, 2004. http://dx.doi.org/10.1007/978-1-4419-8955-0_10.

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Krisher, Rebecca L., and Jason R. Herrick. "Oocyte Metabolism and Its Relationship to Developmental Competence." In Oocyte Physiology and Development in Domestic Animals, 165–89. Oxford, UK: Wiley-Blackwell, 2013. http://dx.doi.org/10.1002/9781118538074.ch9.

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Van Blerkom, Jonathan. "Molecular Mining of Follicular Fluid for Reliable Biomarkers of Human Oocyte and Embryo Developmental Competence." In Practical Manual of In Vitro Fertilization, 677–85. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4419-1780-5_75.

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Van Blerkom, Jonathan. "Molecular Mining of Follicular Fluid for Reliable Biomarkers of Human Oocyte and Embryo Developmental Competence." In In Vitro Fertilization, 929–37. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-319-43011-9_78.

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Van Blerkom, Jonathan. "Molecular Mining of Follicular Fluid for Reliable Biomarkers of Human Oocyte and Embryo Developmental Competence." In Gamete Assessment, Selection and Micromanipulation in ART, 377–91. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-8360-1_27.

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Conference papers on the topic "Oocytes competence"

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Tri, Dao Quang, Pham Truong Duy, Cao Hoang Nam, Bui Hong Thuy, and Nguyen Van Thuan. "DEVELOPMENTAL COMPETENCE AND CHARACTERISTICS OF PRONUCLEAR STAGE OF EMBRYOS OBTAINED FROM Bos taurus OOCYTES AND Bos gaurus SPERMATOZOA VIA INTRACYTOPLASMIC SPERM INJECTION." In NGHIÊN CỨU VÀ GIẢNG DẠY SINH HỌC Ở VIỆT NAM - BIOLOGICAL RESEARCH AND TEACHING IN VIETNAM. Nhà xuất bản Khoa học tự nhiên và Công nghệ, 2022. http://dx.doi.org/10.15625/vap.2022.0062.

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Weiguo Feng, Guohui Wang, Zhifang Pan, and Chune Ren. "The effects of granulosa cell apoptosis on the developmental competence of bovine oocytes: A study using the well-in-well culture system." In 2013 ICME International Conference on Complex Medical Engineering (CME 2013). IEEE, 2013. http://dx.doi.org/10.1109/iccme.2013.6548301.

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Reports on the topic "Oocytes competence"

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Hansen, Peter J., Zvi Roth, and Jeremy J. Block. Improving oocyte competence in dairy cows exposed to heat stress. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7598163.bard.

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Abstract:
Original Objectives. The overall goal is to develop methods to increase pregnancy rate in lactating dairy cows exposed to heat stress through methods that minimize damage to the oocyte and embryo caused by heat stress. Objectives were as follows: (1) examine the protective effects of melatonin on developmental competence of oocytes exposed to elevated temperature in vitro; (2) test whether melatonin feeding can improve developmental competence of oocytes in vivo and, if so, whether effects are limited to the summer or also occur in the absence of heat stress; and (3) evaluate the effectiveness of improving fertility by facilitating follicular turnover in the summer and winter. Revised Objectives. (1) Examine protective effects of melatonin and follicular fluid on developmental competence of oocytes exposed to elevated temperature in vitro; (2) examine the protective effects of melatonin on developmental competence of embryos exposed to elevated temperature in vitro; (3) evaluate effectiveness of improving fertility by administering human chorionicgonadotropin (hCG) to increase circulating concentrations of progesterone and evaluate whether response to hCG depends upon genotype for four mutations reported to be related to cow fertility; and (4) identify genes with allelic variants that increase resistance of embryos to heat shock. Background. The overall hypothesis is that pregnancy success is reduced by heat stress because of damage to the oocyte and cleavage-stage embryo mediated by reactive oxygen species (ROS), and that fertility can be improved by provision of antioxidants or by removing follicles containing oocytes damaged by heat stress. During the study, additional evidence from the literature indicated the potential importance of treatment with chorionicgonadotropin to increase fertility of heat- stressed cows and results from other studies in our laboratories implicated genotype as an important determinant of cow fertility. Thus, the project was expanded to evaluate hCG treatment and to identify whether fertility response to hCG depended upon single nucleotide polymorphisms (SNP) in genes implicated as important for cow fertility. We also evaluated whether a SNP in a gene important for cellular resistance to heat stress (HSPA1L, a member of the heat shock protein 70 family) is important for embryonic resistance to elevated temperature. Major conclusions, solutions & achievements. Results confirmed that elevated temperature increases ROS production by the oocyte and embryo and that melatonin decreases ROS. Melatonin reduced, but did not completely block, damaging effects of heat shock on the oocyte and had no effect on development of the embryo. Melatonin was protective to the oocyte at 0.1-1 μM, a concentration too high to be achieved in cows. It was concluded that melatonin is unlikely to be a useful molecule for increasing fertility of heat-stressed cows. Treatment with hCG at day 5 after breeding increased first-service pregnancy rate for primiparous cows but not for multiparous cows. Thus, hCG could be useful for increasing fertility in first-parity cows. The effectiveness of hCG depended upon genotype for a SNP in COQ9, a gene encoding for a mitochondrial-function protein. This result points the way to future efforts to use genetic information to identify populations of cows for which hormone treatments will be effective or ineffective. The SNP in HSPA1L was related to embryonic survival after heat shock. Perhaps, genetic selection for mutations that increase cellular resistance to heat shock could be employed to reduce effects of heat stress on fertility. Implications, both scientific and agricultural. This project has resulted in abandonment of one possible approach to improve fertility of the heat-stressed cow (melatonin therapy) while also leading to a method for improving fertility of primiparous cows exposed to heat stress (hCG treatment) that can be implemented on farms today. Genetic studies have pointed the way to using genetic information to 1) tailor hormonal treatments to cow populations likely to respond favorably and 2) select animals whose embryos have superior resistance to elevated body temperatures.
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