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Journal of Fish Diseases Sep 2021Atresia of ovarian follicles, that is the degenerative process of germ cells and their associated somatic cells, is a complex process involving apoptosis, autophagy and... (Review)
Review
Atresia of ovarian follicles, that is the degenerative process of germ cells and their associated somatic cells, is a complex process involving apoptosis, autophagy and heterophagy. Follicular atresia is a normal component of fish oogenesis and it is observed throughout the ovarian cycle, although it is more frequent in regressing ovaries during the postspawning period. An increased occurrence of follicular atresia above physiological rates reduces fish fecundity and even causes reproductive failure in both wild and captive-reared fish stocks, and hence, this phenomenon has a wide range of implications in applied sciences such as fisheries and aquaculture. The present article reviews the available literature on both basic and applied traits of oocyte loss by atresia, including its morpho-physiological aspects and factors that cause a supraphysiological increase of follicular atresia. Finally, the review presents the use of early follicular atresia identification in the selection process of induced spawning in aquaculture and the implications of follicular atresia in fisheries management.
Topics: Animals; Aquaculture; Female; Fertility; Fishes; Follicular Atresia; Oogenesis; Ovarian Follicle
PubMed: 34132409
DOI: 10.1111/jfd.13469 -
The International Journal of... 2008In this paper, we summarise studies which have been carried out on the metabolism of nucleic acids (maternal RNA, DNA, nucleolytic enzymes) in avian oocytes and embryos... (Review)
Review
In this paper, we summarise studies which have been carried out on the metabolism of nucleic acids (maternal RNA, DNA, nucleolytic enzymes) in avian oocytes and embryos (Japanese quail, Coturnix coturnix japonica ) within the last 10 years in the Institute of Genetics and Animal Breeding of the Polish Academy of Sciences. The accumulation of maternal RNA in the quail oocyte during oogenesis is shown and discussed. Several individual transcripts were identified in RNA from the germinal disc and some also in extraembryonic RNA under the perivitelline membrane. The presence of the transcript encoding chick zona pellucida C protein (chZPC) points to the possibility of ZPC synthesis by the oocyte itself. The transcript encoding AA-NAT (arylalkylamine N-acetyltransferase, the penultimate enzyme in melatonin synthesis) was present in 2 forms (with and without an intron) and the ratio of the two forms changes during oogenesis. Melatonin and the two enzymes engaged in its synthesis (AA-NAT and HIOMT) have been found in the egg yolk; their transcripts and the transcripts of the melatonin receptors mel-1a,b and c are present in RNA from the germinal discs. This suggests a possible role for melatonin in early avian development. DNases I and II activity has been detected in the germinal disc and the cytoplasmic layer under the perivitelline membrane. We propose that they participate in degradation of supernumerary sperm entering avian oocytes during polyspermic fertilisation. A hypothesis to explain the selection of a single sperm participating in the formation of the zygotic nucleus is discussed; we propose that sperm entry into the centre of the germinal disc is the essential event underlying the selection mechanism.
Topics: Animals; Female; Fertilization; Male; Oocytes; Oogenesis; Spermatozoa
PubMed: 18311709
DOI: 10.1387/ijdb.072329ob -
Scientific Reports Apr 2022The study of developmental processes in Rhodnius prolixus has recently advanced with the sequencing of the genome. In this work, we analyze the maternal gene expression...
The study of developmental processes in Rhodnius prolixus has recently advanced with the sequencing of the genome. In this work, we analyze the maternal gene expression driving oogenesis and early embryogenesis in R. prolixus. We examined the transcriptional profile of mRNAs to establish the genes expressed across the ovary, unfertilized eggs and different embryonic stages of R. prolixus until the formation of the germ band anlage (0, 12, 24, and 48 h post egg laying). We identified 81 putative maternal and ovary-related genes and validated their expression by qRT-PCR. We validate the function of the ortholog gene Bicaudal-D (Rp-BicD) by in situ hybridization and parental RNAi. Consistent with a role in oogenesis and early development of R. prolixus, we show that lack of Rp-BicD does not significantly affect oogenesis but impairs the formation of the blastoderm. Based on our findings, we propose three times of action for maternal genes during oogenesis and embryogenesis in R. prolixus.
Topics: Animals; Embryonic Development; Female; Gene Expression; Oogenesis; RNA Interference; Rhodnius
PubMed: 35449214
DOI: 10.1038/s41598-022-09874-7 -
Cell Reports Nov 2023Although single-cell multi-omics technologies are undergoing rapid development, simultaneous transcriptome and proteome analysis of a single-cell individual still faces...
Although single-cell multi-omics technologies are undergoing rapid development, simultaneous transcriptome and proteome analysis of a single-cell individual still faces great challenges. Here, we developed a single-cell simultaneous transcriptome and proteome (scSTAP) analysis platform based on microfluidics, high-throughput sequencing, and mass spectrometry technology to achieve deep and joint quantitative analysis of transcriptome and proteome at the single-cell level, providing an important resource for understanding the relationship between transcription and translation in cells. This platform was applied to analyze single mouse oocytes at different meiotic maturation stages, reaching an average quantification depth of 19,948 genes and 2,663 protein groups in single mouse oocytes. In particular, we analyzed the correlation of individual RNA and protein pairs, as well as the meiosis regulatory network with unprecedented depth, and identified 30 transcript-protein pairs as specific oocyte maturational signatures, which could be productive for exploring transcriptional and translational regulatory features during oocyte meiosis.
Topics: Animals; Mice; Transcriptome; Proteome; Oocytes; Oogenesis; Gene Expression Profiling; Meiosis
PubMed: 37976159
DOI: 10.1016/j.celrep.2023.113455 -
PloS One 2022Tea plant (Camellia sinensis) is one of the most important horticultural cash crops, and tea green leafhopper (Matsumurasca onukii) is an extremely harmful sap-sucking...
Tea plant (Camellia sinensis) is one of the most important horticultural cash crops, and tea green leafhopper (Matsumurasca onukii) is an extremely harmful sap-sucking pest of tea plant. Serious generation overlapping, which is mainly caused by the long oviposition period, leads to poor control effect of pesticides on this pest in the tea plantation. But the intuitive evidences of continuous oogenesis and egg-laying of this pest are still lacking, which seriously hindered the development of genetic control methods. Here, we clarified the main structures of the inner reproductive system of tea green leafhopper female adult. Oviposition behaviors were monitored as well, and six oviposition steps were recorded. According to the maturity of oocytes, the maturity stages of the reproductive system under different copulation periods were classified into 4 stages. For female adults at stage IV, mature and immature oocytes were presented simultaneously, and the developmental levels of oocytes were asynchronous among different ovarioles. The proportion of gravid females with mature oocytes significantly increased when the continuous copulation time was prolonged. In sync with the development of the ovary maturity, female adults started to slightly deposit eggs at the 5th day, and then increased dramatically. In addition, we found that, whether mature or immature, oocytes in the ovarioles always emitted green fluorescence under blue light excitation, which in turn provide solid proof for the new egg detection method from the insect physiology point of view.
Topics: Animals; Female; Hemiptera; Oocytes; Oogenesis; Oviposition; Reproduction
PubMed: 35176082
DOI: 10.1371/journal.pone.0263933 -
Journal of Assisted Reproduction and... Apr 2022The most important factor associated with oocytes' developmental competence has been widely identified as the presence of chromosomal abnormalities. However, growing... (Review)
Review
The most important factor associated with oocytes' developmental competence has been widely identified as the presence of chromosomal abnormalities. However, growing application of genome-wide sequencing (GS) in population diagnostics has enabled the identification of multifactorial genetic predispositions to sub-lethal pathologies, including those affecting IVF outcomes and reproductive fitness. Indeed, GS analysis in families with history of isolated infertility has recently led to the discovery of new genes and variants involved in specific human infertility endophenotypes that impact the availability and the functionality of female gametes by altering unique mechanisms necessary for oocyte maturation and early embryo development. Ongoing advancements in analytical and bioinformatic pipelines for the study of the genetic determinants of oocyte competence may provide the biological evidence required not only for improving the diagnosis of isolated female infertility but also for the development of novel preventive and therapeutic approaches for reproductive failure. Here, we provide an updated discussion and review of the progresses made in preconception genomic medicine in the identification of genetic factors associated with oocyte availability, function, and competence.
Topics: Embryonic Development; Female; Genomics; Humans; Infertility; Oocytes; Oogenesis
PubMed: 35124783
DOI: 10.1007/s10815-022-02411-5 -
Seminars in Cell & Developmental Biology Dec 2018In virtually all sexually reproducing animals, oocytes arrest in meiotic prophase and resume meiosis in a conserved biological process called meiotic maturation. Meiotic... (Review)
Review
In virtually all sexually reproducing animals, oocytes arrest in meiotic prophase and resume meiosis in a conserved biological process called meiotic maturation. Meiotic arrest enables oocytes, which are amongst the largest cells in an organism, to grow and accumulate the necessary cellular constituents required to support embryonic development. Oocyte arrest can be maintained for a prolonged period, up to 50 years in humans, and defects in the meiotic maturation process interfere with the faithful segregation of meiotic chromosomes, representing the leading cause of human birth defects and female infertility. Hormonal signaling and interactions with somatic cells of the gonad control the timing of oocyte meiotic maturation. Signaling activates the CDK1/cyclin B kinase, which plays a central role in regulating the nuclear and cytoplasmic events of meiotic maturation. Nuclear maturation encompasses nuclear envelope breakdown, meiotic spindle assembly, and chromosome segregation whereas cytoplasmic maturation involves major changes in oocyte protein translation and cytoplasmic organelles and is less well understood. Classically, meiotic maturation has been studied in organisms with large oocytes to facilitate biochemical analysis. Recently, the nematode Caenorhabditis elegans is emerging as a genetic paradigm for studying the regulation of oocyte meiotic maturation. Studies in this system have revealed conceptual, anatomical, and molecular links to oocytes in all animals including humans. This review focuses on the signaling mechanisms required to control oocyte growth and meiotic maturation in C. elegans and discusses how the downstream regulation of protein translation coordinates the completion of meiosis and the oocyte-to-embryo transition.
Topics: Animals; Caenorhabditis elegans; Embryonic Development; Humans; Meiosis; Oocytes; Oogenesis; Signal Transduction
PubMed: 29242146
DOI: 10.1016/j.semcdb.2017.12.005 -
Nature Communications Feb 2023In the long-lived naked mole-rat (NMR), the entire process of oogenesis occurs postnatally. Germ cell numbers increase significantly in NMRs between postnatal days 5...
In the long-lived naked mole-rat (NMR), the entire process of oogenesis occurs postnatally. Germ cell numbers increase significantly in NMRs between postnatal days 5 (P5) and P8, and germs cells positive for proliferation markers (Ki-67, pHH3) are present at least until P90. Using pluripotency markers (SOX2 and OCT4) and the primordial germ cell (PGC) marker BLIMP1, we show that PGCs persist up to P90 alongside germ cells in all stages of female differentiation and undergo mitosis both in vivo and in vitro. We identified VASA+ SOX2+ cells at 6 months and at 3-years in subordinate and reproductively activated females. Reproductive activation was associated with proliferation of VASA+ SOX2+ cells. Collectively, our results suggest that highly desynchronized germ cell development and the maintenance of a small population of PGCs that can expand upon reproductive activation are unique strategies that could help to maintain the NMR's ovarian reserve for its 30-year reproductive lifespan.
Topics: Animals; Female; Cell Differentiation; Germ Cells; Mitosis; Oogenesis; Ovarian Reserve; Ovary; Mole Rats
PubMed: 36810851
DOI: 10.1038/s41467-023-36284-8 -
Trends in Genetics : TIG Dec 2017Germ cells develop as a cyst of interconnected sibling cells in a broad range of organisms in both sexes. A well-established function of intercellular connectivity is to... (Review)
Review
Germ cells develop as a cyst of interconnected sibling cells in a broad range of organisms in both sexes. A well-established function of intercellular connectivity is to transport cytoplasmic materials from 'nurse' cells to oocytes, a critical process for developing functional oocytes in ovaries of many species. However, there are situations where connectivity exists without a nursing mechanism, and the biological meaning of such connectivity remains obscure. In this review, we summarize current knowledge on the formation of intercellular connectivity, and discuss its meaning by visiting multiple examples of germ cell connectivity observed in evolutionarily distant species.
Topics: Animals; Cytoplasm; Female; Germ Cells; Oocytes; Oogenesis; Ovary
PubMed: 28947158
DOI: 10.1016/j.tig.2017.09.001 -
The EMBO Journal May 2023Human in vitro oogenesis provides a framework for clarifying the mechanism of human oogenesis. To create its benchmark, it is vital to promote in vitro oogenesis using a...
Human in vitro oogenesis provides a framework for clarifying the mechanism of human oogenesis. To create its benchmark, it is vital to promote in vitro oogenesis using a model physiologically close to humans. Here, we establish a foundation for in vitro oogenesis in cynomolgus (cy) monkeys (Macaca fascicularis): cy female embryonic stem cells harboring one active and one inactive X chromosome (Xa and Xi, respectively) differentiate robustly into primordial germ cell-like cells, which in xenogeneic reconstituted ovaries develop efficiently into oogonia and, remarkably, further into meiotic oocytes at the zygotene stage. This differentiation entails comprehensive epigenetic reprogramming, including Xi reprogramming, yet Xa and Xi remain epigenetically asymmetric with, as partly observed in vivo, incomplete Xi reactivation. In humans and monkeys, the Xi epigenome in pluripotent stem cells functions as an Xi-reprogramming determinant. We further show that developmental pathway over-activations with suboptimal up-regulation of relevant meiotic genes impede in vitro meiotic progression. Cy in vitro oogenesis exhibits critical homology with the human system, including with respect to bottlenecks, providing a salient model for advancing human in vitro oogenesis.
Topics: Animals; Female; Humans; Macaca fascicularis; Oocytes; Oogenesis; Ovary; Embryonic Stem Cells
PubMed: 36929479
DOI: 10.15252/embj.2022112962