Academic literature on the topic 'Gonad development'
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Journal articles on the topic "Gonad development"
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Linhartová, Z., M. Havelka, M. Pšenička, and M. Flajšhans. "Interspecific hybridization of sturgeon species affects differently their gonadal development." Czech Journal of Animal Science 63, No. 1 (December 4, 2017): 1–10. http://dx.doi.org/10.17221/37/2016-cjas.
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Gonad development in fish is generally assumed to be negatively influenced by interspecific hybridization, resulting in sterility or sub-sterility. However, this is not the case in sturgeons (Acipenseridae), in which fertile hybrids are common. In the present study, we investigated gonad development in several sturgeon interspecific hybrids and purebred species. Six interspecific hybrid groups and three purebred groups were analyzed including 20 hybrid specimens with even ploidy, 40 specimens having odd ploidy levels, and 30 purebred specimens. Hybrids of species with the same ploidy (even ploidy – 2n, 4n) exhibited normally developed gonads similar to those seen in purebred specimens. In contrast, hybrids of species differing in ploidy (odd ploidy – 3n) did not display fully developed gonads. Ovaries were composed of oocytes or nests of differentiating oocytes that ceased development in early stages of meiosis (pachytene to zygotene) with a higher content of adipose and apoptotic tissue. Testes contained single spermatogonia along with Sertoli cells and spaces lacking germ cells. The obtained results showed that gonad development was influenced by genetic origin and ploidy of the sturgeon hybrids and were consistent with full fertility of hybrids with even ploidy. Sterility of females, but possibly limited fertility of males, is suggested for hybrids with odd ploidy.
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Lin, Feng, Konrad Dabrowski, and Lucy P. M. Timmermans. "Early gonadal development and sexual differentiation in muskellunge (Esox masquinongy)." Canadian Journal of Zoology 75, no. 8 (August 1, 1997): 1262–69. http://dx.doi.org/10.1139/z97-149.
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Primordial germ cells (PGCs) were first identified in muskellunge (Esox masquinongy) of 14 mm total length (TL) 3 weeks post fertilization. At 32 mm TL, gonad strings were complete and formed a typical gonad shape in cross section. Blood vessels were first found in the gonads with Crossmon staining at 46 mm TL. Some of the PGCs underwent mitotic division at this stage. The ovarian sac started to develop in a fish of 82 mm TL, while the germ cells were still considered to be undifferentiated. In a fish of 138 mm TL, female gonads could be clearly identified from the ovarian sac and groups of oogonia, whereas in another type of gonad, the morphology of undifferentiated gonads was maintained. Germ cells became numerous in both sexes at 211 mm TL. Female gonads contained lobes with germ cells, including oogonia, early-prophase oocytes, and large oocytes. Spermatogonia and cells undergoing mitosis were observed in the testis. Ovaries in a fish of 250 mm TL were at the early stage of perinucleolus (early diplotene). Our observations indicate that in muskellunge (i) the PGCs remained in a resting state for up to 8 weeks post fertilization, (ii) gametogenesis occurred earlier in females than in males, (iii) the gonads developed from an undifferentiated stage directly into an ovary or testis, and (iv) the somatic elements in the gonads differentiated prior to the germ cells.
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Parker, L. E., S. Culloty, R. M. O'Riordan, B. Kelleher, S. Steele, and G. Van der Velde. "Preliminary study on the gonad development of the exotic ascidian Styela clava in Cork Harbour, Ireland." Journal of the Marine Biological Association of the United Kingdom 79, no. 6 (December 1999): 1141–42. http://dx.doi.org/10.1017/s0025315499001472.
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The reproductive cycle, development and spatial organization of the gonads of an exotic ascidian, Styela clava, were studied in Cork Harbour, Ireland. Monthly histological samples enabled the division of gonad development into six main stages, ranging from `inactive' to `regression'. Gonad development was asynchronous in the population, with more than one stage being found within some months. Gametogenesis was observed from February–November, but peaked between August–October. Spawning took place in September–October, followed by gonad regression in November–December.
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Young, P. C., G. J. West, R. J. McLoughlin, and R. B. Martin. "Reproduction of the commercial scallop, Pecten fumatus, Reeve, 1852 in Bass Strait, Australia." Marine and Freshwater Research 50, no. 5 (1999): 417. http://dx.doi.org/10.1071/mf98149.
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To examine the reproduction of Pecten fumatus Reeve, 1852, samples were taken monthly from beds off King Island and in Banks Strait, from July 1986 to July 1987. For each sample the mean gonad-free tissue weight and standardized gonad weight were calculated. The percentage of the sample with each of five macroscopically determined reproductive stages was also measured. Changes in the proportion of cell types within the ovarian part of the gonad were determined by histological and stereological methods. A seasonal cycle of gonadal development occurred at each site, commencing at the time of lowest water temperatures and highest nutrient concentrations. This development progressively increased as the nutrient concentrations declined. No correlation was seen between chlorophyll a and gonad condition. A synchrony in gonad condition was present among individuals in samples; this was greatest at Banks Strait where gonads were larger, and phosphate, nitrate and silicate concentrations were significantly greater. There was no reduction in somatic tissue weight with increase in gonad tissue weight. Maximum gonad development preceded spatfall at each site by about one month.
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Faizah, Ria, and Budi Iskandar Prisantoso. "BIOLOGI REPRODUKSI TUNA MATA BESAR (Thunnus obesus) YANG TERTANGKAP DI SAMUDERA HINDIA." BAWAL Widya Riset Perikanan Tangkap 3, no. 2 (February 7, 2017): 129. http://dx.doi.org/10.15578/bawal.3.2.2010.129-137.
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Tujuan penelitian ini adalah untuk mendapatkan informasi mengenai aspek reproduksi ikan tuna mata besar (Thunnus obesus) di perairan Samudera Hindia. Sebanyak 42 contoh gonad dari ikan tuna mata besar yang tertangkap perairan Samudera Hindia antara bulan Maret sampai Oktober 2008 digunakan dalam penelitian ini. Pengamatan meliputi struktur morfologi gonad ikan, perkembangan gonad, diameter telur, dan fekunditas. Hasil penelitian ini menunjukan bahwa ikantuna mata besar yang tertangkap memiliki tingkat kematangan gonad I, II, dan IV. Nilai gonado somatic index rata-rata tuna mata besar semakin meningkat seiring dengan meningkatnya tingkat kematangan gonad. Musim pemijahan untuk tuna mata besar diduga terjadi pada bulan Oktober. Tuna mata besarmemiliki fekunditas antara 8.163.715-10.365.317 butir dan memiliki pola pemijahan berganda. The objective of this research is to study the reproductive biology of big eye tuna (Thunnus obesus) from Indian Ocean. A numbers of 42 gonad samples were taken from fresh individuals captured in the Indian Ocean during period of March until October 2008. The observation comprised of morphological structure of gonad, gonad development, oocytes diameter, and batch fecundity. The results showed that the gonad maturity stages of big eye tuna were ranged from immature (the gonad maturity stage of I and II) to mature (the gonad maturity stage of IV), and the gonado somatic index value increase along with increase of gonad maturity. Spawning season for big eye tuna estimated was in October, range of fecundity were 8.163.715-10.365.317 oocytes, and the spawning type waspartial spawned.
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Castiglioni, Daniela da Silva, Maria Lucia Negreiros-Fransozo, Laura S. López Greco, Aron F. Silveira, and Sérgio O. Silveira. "Gonad development in females of fiddler crab Uca rapax (Crustacea, Brachyura, Ocypodidae) using macro and microscopic techniques." Iheringia. Série Zoologia 97, no. 4 (December 2007): 505–10. http://dx.doi.org/10.1590/s0073-47212007000400022.
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The morphology of the ovaries in Uca rapax (Smith, 1870) was described based on macroscopic and microscopic analysis. Females were collected in Itamambuca mangrove, Ubatuba, state of São Paulo, Brazil. In the laboratory, 18 females had their ovaries removed and prepared for histology. Each gonad developmental stage was previously determined based on external and macroscopic morphology and afterwards each stage was microscopically described. The ovaries of U. rapax showed a pronounced macroscopic differentiation in size and coloration with the maturation of the gonad, with six ovarian developmental stages: immature, rudimentary, developing, developed, advanced and spent. During the vitellogenesis, the amount of oocytes in secondary stage increases in the ovary, resulting in a change in coloration of the gonad. Oogonias, primary oocytes, secondary oocytes and follicular cells were histologically described and measured. In female’s ovaries of U. rapax the modifications observed in the oocytes during the process of gonad maturation are similar to descriptions of gonads of other females of brachyuran crustaceans. The similarities are specially found in the morphological changes in the reproductive cells, and also in the presence and arrange of follicle cells during the process of ovary maturation. When external morphological characteristics of the gonads were compared to histological descriptions, it was possible to observe modifications that characterize the process in different developmental stages throughout the ovarian cycle and, consequently, the macroscopic classification of gonad stages agree with the modifications of the reproductive cells.
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Tarsim, M. Zairin Junior, and E. Riani. "Effect of Estradiol-17β Injection on Gonad Development of White Shrimp (Litopenaeus vannamei)." Jurnal Akuakultur Indonesia 6, no. 1 (January 1, 2007): 17. http://dx.doi.org/10.19027/jai.6.17-25.
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<p>The methods for hormonal control of shrimp reproduction are very limited, and only eyestalk ablation is used to induce ovarian development and spawning in shrimp farming. The occurrence of vertebrate-type steroid hormones in crustaceans have been reported, however, their physiological role are not sufficiently understood. The present study analyzed the effect of estradiol-17β injection on gonad development of white shrimp, <em>Litopenaeus vannamei</em>. The estradiol-17β dose 0.10 μg/g body weight were used. The treatments consisted of control, single injection (day 0) and double injection (day 0 and 6). The females broodstock were cultured for 12 days. The result showed that estradiol-17β had positive effect on gonad development. The gonado somatic index (GSI) and oocytes diameter in treatment larger than the control. Double injection had highest effect with ∆GSI and oocytes diameter was 0.453<sup> </sup> and 23.97 µm, respectively. The only oocytes previtelogenesis was found in gonad. It indicated that estradiol-17β important to induce endogenous vitellogenesis. Gonad development probably affected by gonad inhibiting hormone in the eyestalk. It was inhibited oocyte maturation. The polypeptide sub unit was observed in vitellin of ovari by SDS-PAGE. The molecular weights of approximately 95, 98, 109 and two units higher than 118 kDa of protein marker.</p> <p>Keywords: Gonad, estradiol-17β, oocyte, <em>Litopenaeus vannamei</em></p> <p> </p> <p>ABSTRAK</p> <p>Teknologi reproduksi dalam pembenihan udang belum mengalami perkembangan yang signifikan. Pada umumnya untuk mempercepat kematangan gonad induk udang digunakan teknik ablasi. Mekanisme dan peranan hormon pada proses reproduksi udang belum banyak diketahui. Keberadaan hormon steroid pada krustase telah dikemukaan oleh beberapa peneliti, tetapi peranannya belum banyak diketahui. Pada penelitian ini dikaji pengaruh penyuntikan hormon estradiol-17β pada perkembangan gonad induk udang putih (<em>Litopenaeus vannamei</em>). Penelitian ini menggunakan dosis 0,10 μg/g bobot tubuh dengan perlakuan penyuntikan tunggal (hari ke-0) dan ganda (hari ke-0 dan ke-6). Sebagai pembanding dilakukan uji tanpa perlakuan (kontrol). Untuk melihat respon perkembangan gonad, pemeliharaan induk dilakukan selama 12 hari. Hasil penelitian menunjukkan bahwa estradiol-17β berpengaruh positif pada perkembangan gonad. <em>Gonado somatic index </em>(GSI) dan rata-rata diameter oosit pada perlakuan relative lebih tinggi dibandingkan kontrol. Penyuntikan ganda memberikan pengaruh paling besar dengan peningkatan GSI sebesar 0,453<sup> </sup> dan rata-rata diameter oosit 23,97 µm. Oosit pada gonad hanya mampu berkembang hingga tahap previtelogenesis. Hal ini menunjukkan bahwa estradiol-17β berperang dalam vitelogenesis endogenous. Keberadaan hormon penghambat perkembangan yang dihasilkan tangkai mata diduga menyebabkan oosit tidak dapat mencapai matang. Analisis SDS-PAGE menunjukkan bahwa protein kuning telur pada gonad terdapat 5 sub unit dengan perkiraan bobot 95, 98, 109 kDa dan dua unit >118 kDa.</p> <p>Kata kunci: Gonad, estradiol-17β, oosit, <em>Litopenaeus vannamei</em></p>
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Vives, Ailet, Tamara Rubilar, María-Dinorah Herrero-Pérezrul, and Bertha-Patricia Ceballos-Vázquez. "Reproduction of the sea urchin Tripneustes depressus (Camarodonta: Toxopneustidae) in Bahía de La Paz, Baja California Sur, Mexico." Revista de Biología Tropical 69, Suppl.1 (March 23, 2021): 202–18. http://dx.doi.org/10.15517/rbt.v69isuppl.1.46353.
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Introduction: Sea urchin gonads (roe or uni) are considered a culinary delicacy worldwide. However, only a few species are considered edible and commercialized. The sea urchin Tripneustes depressus has generated the interest of producers in Baja California Sur, Mexico, due to the quality of its gonads. A biological basis for designing a management strategy is key to consider its commercial exploitation. Objective: To determine the reproductive season of T. depressus through description of the gonad stages and reproductive cycle, and to establish its relationship with environmental factors. Methods: We collected monthly samples (October 2016-September 2017), recording in-situ temperature and photoperiod. We evaluated a sample of 1 055 specimens for demographic characteristics, using total weight (g) and test diameter (cm). We also did a histological analysis of gonads from 178 individuals. Results: Average test diameter was 9.70 ± 0.03 cm (5-12.50 cm). Based on the proportion into the gonad of sexual (gametes) and somatic (nutritive phagocytes) cells, we propose five gonad stages (growing, premature, mature, spawning, and intergametic) for both sexes. There were two times of the year when gonads were heaviest and closely corresponded to the growing stage, coinciding with the highest proportions of nutritive phagocytes. Gonad development (growing and premature stages) peaks in the months with the longest daylight periods, with spawning in the shortest daylight periods. Conclusions: Gonad wet weight and adjusted gonad weight are good indicators of the reproductive season of T. depressus. The lowest gonad wet weights were matched the spawning peak in the shortest daylight period (January and March).
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Piprek, Rafal P., Michal Kolasa, Dagmara Podkowa, Malgorzata Kloc, and Jacek Z. Kubiak. "Tissue-specific knockout of E-cadherin (Cdh1) in developing mouse gonads causes germ cells loss." Reproduction 158, no. 2 (August 2019): 149–59. http://dx.doi.org/10.1530/rep-18-0621.
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The normal course of gonad development is critical for the sexual development and reproductive capacity of the individual. During development, an incipient bipotential gonad which consists of unorganized aggregate of cells, must differentiate into highly structured testis or ovary. Cell adhesion molecules (CAMs) are a group of proteins crucial for segregation and aggregation of different cell types to form different tissues. E-cadherin (Cdh1) is one of the CAMs expressed in the developing gonads. We used tissue-specific knockout of Cdh1 gene in OCT4+ germ cells and, separately, in SF1+ somatic cells of developing gonads. The knockout of E-cadherin in somatic cells caused decrease in the number of germ cells, while the knockout in the germ cells caused their almost complete loss. Thus, the presence of E-cadherin in both the germ and somatic cells is necessary for the survival of germ cells. Although the lack of E-cadherin did not impair cell proliferation, it enhanced apoptosis, which was a possible cause of germ cell loss. However, the somatic cells of the gonad differentiated normally into Sertoli cells in the testis cords, and into follicular cells in the ovaries. The testis and ovigerous cords maintained their integrity; they were covered by continuous basement membranes. The testicular interstitium with steroidogenic fetal Leydig cells did not show any noticeable changes. However, in the female gonads, because of the lack of germ cells, the ovarian follicles were absent. The sex determination and sexual differentiation of the gonad were not impaired. These results underscore an important role of E-cadherin in germ cell survival and gonad development.
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Oliveira, MR, NB Silva, ME Yamamoto, and S. Chellappa. "Gonad development and reproduction of the ballyhoo half beak, Hemiramphus brasiliensis from the coastal waters of Rio Grande do Norte, Brazil." Brazilian Journal of Biology 75, no. 2 (May 2015): 324–30. http://dx.doi.org/10.1590/1519-6984.12113.
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The gonad development and reproductive aspects of Hemiramphus brasiliensis from the coastal waters of Rio Grande do Norte, Brazil were verified. This paper presents data on the length-weight relationship, sex ratio, length at first sexual maturity, gonad development, reproductive period and fecundity of H. brasiliensis. Females of this species predominated in the sampled population and were larger in size than the males. The length at the first sexual maturation of males was 20.8 cm and that of females was 21.5 cm. The macroscopic characteristics of the gonads indicated four maturation stages. Histological studies of gonads of H. brasiliensis showed six phases of oocyte development and four phases of spermatocyte development. The batch fecundity of this species is 1153 (±258.22) oocytes for 50 g body weight of female. The microscopic characteristics of gonad development indicate that H. brasiliensis is a multiple spawner, with active reproductive period during the months of January to June and October. The reproductive period of this species is independent of the rainy period of the region.
Dissertations / Theses on the topic "Gonad development"
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Ward, Katherine. "The role of WNT4 in mouse gonad development." Thesis, Institute of Cancer Research (University Of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405043.
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Murray, Tessa Jane. "The regulation and dysregulation of fetal gonad development." Thesis, University of Aberdeen, 2001. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU534397.
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Links between declining human male fertility (decreased sperm counts, increased incidence of both testicular cancer and genital abnormalities) and the increasing prevalence of endocrine disrupting chemicals (EDCs) in the environment have been reported. We aim to characterise the key developmental processes occurring during human fetal gonad development. Human fetal testis development was characterised by a transient increase in interstitial area proliferation between 13-19 weeks which was accompanied by an increase in steroidogenic acute regulatory protein (StAR) and steroidogenic enzymes. Androgen receptor was expressed by the peritubular myoid cells which had a high bcl-2:bax ratio, indicative of cell survival. Estrogen receptors ( and ) were localised to distinct cell populations. In the ovine gonad similar developmental processes occurred, and comparison with human ovarian development demonstrated interesting parallels. After optimisation, the explant culture system revealed that exposure to the insecticidal EDC dieldrin, at low (<1 ppb) doses reduced LH-stimulated testosterone output in the human fetal testis. This was accompanied by dose-specific changes to the testis proteome, alterations in bcl-2:bax ratios in favour of apoptosis and a down-regulation in StAR expression relative to the LH-treated controls. In conclusion, the processes of proliferation apoptosis, steroidogenesis and steroid action are crucial during fetal gonad development. We demonstrated that in utero exposure to dieldrin may cause reproductive dysfunction in adult life due to reduced steroidogenesis in the fetal gonad; mediated through a down-regulation in StAR expression and alterations in the regulation of gonadal apoptosis.
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Siggers, Pamela. "Isolation and analysis of genes involved in mouse gonad development." Thesis, Open University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411260.
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Brixey, Rachel J. E. "Genetic analyses of MAP kinase signalling in mouse gonad development." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:54242de2-8e43-4cf2-ad12-d94a2c187c44.
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Sexual development begins with the process by which the bipotential gonads of the embryonic urogenital ridge develop into either testes or ovaries. In the mouse, sex determination occurs at around 11.5 dpc and depends on the presence or absence of the Y chromosome and the associated activity of the testis-determining gene, Sry, in supporting cell precursors. The mutually antagonistic male and female developmental pathways are regulated by many cellular and molecular processes, disruption of which can lead to disorders of sex development (DSDs). However, many of the molecular mechanisms regulating the differentiation of the two gonads are still unknown. The boygirl (byg) mutant was identified in an ENU-based forward genetic screen for embryos with gonadal abnormalities. On the C57BL/6J background, XY byg/byg homozygotes exhibited complete embryonic gonadal sex reversal. The defective gene in byg, Map3k4, is a component of the mitogen-activated protein (MAP) kinase signalling pathway and provides the first evidence for a function of this pathway in sex determination. This thesis describes experiments aimed at investigating the cellular and molecular basis of the sex reversal phenotype associated with the XY Map3k4byg/byg mutant. Cellular characterisations revealed a defect in male-specific proliferation at 11.5 dpc, which was attributed to a defect in Sry up-regulation. Elucidation of the downstream kinases activated by MAP3K4 during sex determination was attempted, with particular focus on identifying a role for p38α MAP kinase (MAPK). Using a conditional knockout approach, the function of p38α in Steroidogenic factor-1 (Sf1)-positive somatic cells was assessed. However, specific inactivation in these cells did not affect gonad development. Conditional inactivation of Map3k4 itself in these Sf1¬-positive cells also did not disrupt gonad development, suggesting that this pathway is either initiated in a different cell lineage or at an earlier stage than deletion driven by Sf1-Cre can disrupt. Conditional inactivation of p38α in the Müllerian duct mesenchyme and ovarian granulosa cells using Amhr2-Cre did reveal a function for p38α in female fertility, but did not disrupt embryonic sexual development. Gene knockdown in organ culture was attempted to determine a role for multiple p38 MAPKs in all cell types of the gonad. Therefore, this thesis details further characterisations of a novel signalling pathway important for the expression of Sry, focussing on the role of the p38 MAPKs.
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Haines, Lynn Christine. "Development and differentiation of the embryonic chick gonad : a morphological and molecular study." Thesis, University of Edinburgh, 1998. http://hdl.handle.net/1842/14955.
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In mammals, the timing of sex determination and a small number of the genes involved in gonadal development have been established. However, other so far unidentified genes are clearly involved in gonadal development, in avian and other species. Chick gonadal development was investigated by studying the morphology of the developing gonads and by attempting to gain a better understanding of the genes involved in the initial stages of this developmental process. The first approach was a histological analysis of chick gonadal development over the period from the indifferent gonad stage to the initial stages of ovary and testis differentiation. Secondly, we analyzed the expression of chick homologues to genes involved in mammalian gonadal development, in an attempt to compare gene regulation and timing of gonadal development between mammals and avians. Finally, we used the technique of differential display to both ascertain the feasibility of this approach in the identification of transcripts in a complex developmental system and to isolate novel genes involved in chick gonadal development. As a result of this study we were able to predict that the sex determination event in chicks occurred earlier in embryogenesis than previously documented. We also established that genes involved in mammalian gonadal development were expressed with similar expression profiles in the developing chick gonads. Finally, twelve candidate clones were isolated by differential display, five of which represented novel sequences. Expression profiles, during chick gonadal development and differentiation, were analyzed by Northern analysis and whole mount in situ hybridization to confirm differential expression.
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Rudigier, Lucas Johannes [Verfasser]. "The Role of WT1 and GATA4 during Gonad Development in Mice / Lucas Johannes Rudigier." Berlin : Freie Universität Berlin, 2015. http://d-nb.info/1075190878/34.
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Torres, Cano Alejo. "WT1 in heart and gonad development: a crucial gene for cell plasticity and differentiation." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673447.
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Wt1 is a complex gene that encodes a protein whose best described function is to act as a transcription factor. Wt1 plays a crucial role in several organ developments, including kidneys, liver, heart or gonads. Moreover, Wt1 is implicated in the etiology of a set of syndromes and diseases ranging from cancer to disorders of sex development (DSD). Additionally, Wt1 has been described to play a role in adult homeostasis. In this thesis, I focused on Wt1 role in development, specifically in gonad and heart morphogenesis. For this purpose, I used two previously described Cre mouse models to generate two different Wt1KOs.
The heart is the first organ being formed and it is primarily composed of three layers: the endocardium, the myocardium and the epicardium. The epicardium is a mesothelial layer of cells covering the vertebrate heart surface. Epicardial cells give rise to epicardial derived cells (EPDCs), progenitors of crucial cell types in heart development like vascular smooth muscle cells and cardiac fibroblasts. Moreover, the epicardium contributes to heart morphogenesis by secreting paracrine factors. After myocardial infarction, the epicardium embryonic genetic signature is reactivated. Thus, understanding the mechanisms behind epicardial development constitutes a topic of general interest.
The epicardial genetic program has been previously characterized and the Wt1 role in the regulation of this program has been established. One of the pathways modulated during epicardium development is the BMP4 pathway. The results of this thesis demonstrate that WT1 directly regulates Bmp4 expression. Additionally, exposed results demonstrate how the BMP4 pathway is crucial for epicardial cell maturation, through the regulation of cell morphology, from a cuboidal to a squamous cell shape, epicardial proliferation, and transcriptomic changes. Finally, the data shown in this work indicated that changes and mechanisms described for epicardium may be a phenomenon extrapolated to other mesotheliums like the lung mesothelium.
To better study Wt1 role in the development of other organs, we have characterized the recombination activity of a Wt1Cre mouse model using two different reporter mouse models, the R26RmTmG and the R26RtdRFP. Results demonstrated that Wt1Cre is efficiently activated in hearts and gonads but not in other organs generated from the genital ridge, like the kidney or the adrenal gland. Taking advantage of this, the Wt1Cre mouse model was used to generate a new Wt1KO: the Wt1Cre; Wt1Loxp/GFP. Wt1Cre; Wt1Loxp/GFP mice show a partial embryonic lethality, potentially caused by defects in heart development, but some of them reach adulthood, becoming an ideal model to investigate Wt1 role from embryonic to adult stages. Therefore, we decided to study Wt1role in gonad development in Wt1Cre; Wt1Loxp/GFP mice.
Sex development is a complex and coordinated process that starts with the differentiation of the bipotential gonads. WT1 mutations or haploinsufficiency have been reported in different syndromes and conditions linked to DSD. The study of WT1 role in embryonic development and the impact on adult sex development has been hampered by the complete gonadal agenesis or embryonic lethality presented by other Wt1KO mouse models.
The results presented demonstrate a sharp reduction in Wt1 levels in Wt1Cre; Wt1Loxp/GFP gonads since the bipotential stage. This causes, in the adult, the formation of small, atrophic gonads, a hermaphroditism of the genital tract and external ambiguous genitalia. Besides, the data reported in this thesis demonstrates that Wt1Cre; Wt1Loxp/GFP mice present an impaired gonad embryonic development due to the lack of differentiation of the main cell lineages responsible for gonad development and function: supportive cells, steroidogenic cells and primordial germ cells (PGCs).
Finally, the observed sub-lethality in Wt1Cre; Wt1Loxp/GFP mice is explained by the observation of a severe heart developmental impairment in a portion of Wt1Cre; Wt1Loxp/GFP embryos, whereas others show no apparent heart defects at embryonic stages. Equally, an histological study performed on Wt1Cre; Wt1Loxp/GFP mice also described changes in the spleen and brown adipose tissue.
In summary, our results indicate the importance of morphological changes epicardial cells undergo during development, a process regulated by Wt1 modulation of the BMP4 pathway. In addition, the generation and characterization of the Wt1Cre; Wt1Loxp/GFP mouse renders an informative and useful tool to study Wt1 role beyond embryonic stages and provide a more accurate frame for the understanding of results previously obtained when using the Wt1Cre mouse model.
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Delgado, Cláudia Maria Neves. "Gonad development and hormone titres in Loggerhead Sea Turtles (Caretta caretta) in the NE Atlantic." Doctoral thesis, Universidade da Madeira, 2008. http://hdl.handle.net/10400.13/32.
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The study proposed to describe sexual development in pelagic stage loggerhead sea turtles
Caretta caretta and compare this to hatchlings and adults. It is meant as an ontogenic approach,
in order to understand reproductive development and population composition and their dynamics
in the pelagic environment. The study focused on the pelagic loggerheads that are found in the
waters offshore Madeira Island (Portugal) in the North-eastern Atlantic and use it as a
developmental habitat.
The innovating character of this work relied on the lack of any description regarding the gonad
ontogenesis and reproductive development for the pelagic stage in any of the 7 existing sea
turtle species, all of them in danger of extinction.
Three methods were used to diagnose the sex of each juvenile individual and asses the level of
reproductive development: (1) laparoscopy, (2) gonad biopsy and (3) the assessment of two sex
steroids circulating levels, namely testosterone and estradiol.
In order to cover all life stages and compare data obtained for the juvenile stage, hatchlings
and nesting female adults were sampled at the nearest nesting rookery at Boa Vista Island in the
Cape Verde Archipelago. Gonads from dead hatchlings were collected for gonad histology and
blood was collected from nesting females for sex steroids assessment.
Laparoscopies revealed to be a valid sexing method for the juvenile stage, since gonads are
morphologically differentiated at these size classes. Moreover, laparoscopy was validated using
gonad histology.
Gonad histology of juveniles showed that gonads are already completely differentiated into
ovaries or testes at the size classes examined, but development seems to be quiescent.
Males present already developed seminiferous tubules with spermatogonia lining the interior of
the seminiferous tubule. Female gonads present oocytes at different development stages, but
only oocytes up to stage III were observed. The maximum oocyte diameter in each individual
correlated with body size, suggesting that reproductive development is an on-going process in
juvenile females.
The circulating levels of both testosterone and estradiol in juveniles of both sexes were very low
and consistently lower than the ones observed in the nesting females from Boa Vista Island. No bimodal distribution was found for any of the sex steroids analysed and thus circulating
hormone levels were not a reliable tool for sexing juvenile individuals with a non-invasive
technique. The ratio testosterone:estradiol did not show a bimodal distribution either.
The levels of testosterone correlated with sea surface temperature. The fact that temperatures
observed during this study were below 24ºC might have hindered a differential testosterone
pattern between juvenile males and females.
Sex ratios for this population were generated according to laparoscopy results and compared
among years and size classes. An overall sex ratio of 2 females for each male was found, but
they varied among size classes but not among years. Possible causes for the sex ratios observed
are discussed.
This study is a contribution to our knowledge on the pelagic stage of loggerhead turtles, namely
on the population structure regarding sex ratio, which is a vital tool for implementing
conservation strategies.Orientadores: Thomas Dellinger and Adelino Canário
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Roder, Alexandra Catherine, and Alexandra Catherine Roder. "Influence of Xenorhabdus Symbionts on Gonad Development and Pheromone Production of First-Generation Adult Steinernema Nematodes (Nematoda: Steinernematidae)." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/626344.
Full textAbstract:
Entomopathogenic Steinernema nematodes (Nematoda: Steinernematidae) have a mutualistic relationship with Xenorhabdus bacteria (Gamma-Proteobacteria Enterobacteriaceae). The two partners form an insecticidal alliance that is successful in killing a wide range of insects. A few studies have shown that Steinernema IJs have an enhanced virulence and reproductive fitness when they associate with their cognate symbionts. However, there are unanswered questions regarding the physiological interactions that govern and perpetuate the interactions between different nematode developmental stages and their bacterial partners. In this study, we evaluated gonad development and maturation time of first-generation adults of S. carpocapsae and S. feltiae adults when reared under four bacterial scenarios: a) cognate symbiotic, b) non-cognate symbiotic bacterial strain, c) non-cognate symbiotic bacterial species and d) non-symbiotic bacteria (Serratia proteamaculans). For comparative purposes, we also considered adult nematodes reared in vivo in Galleria mellonella larvae to assess nematode development under natural conditions. Furthermore, in this study we also measured production of nematode pheromones (ascarosides), which play a key role in mating and reproduction. For this purpose, we considered in vitro rearing methods (with cognate and non-cognate Xenorhabdus symbionts) to qualitatively and quantitatively characterize ascarosides produced by first-generation adults. Our data showed that for both Steinernema spp. tested, time to adult maturation and gonad development was tightly dependent on the bacterial conditions under which juveniles were reared. However, contrasting results were observed when assessing total body length and gonad size. S. feltiae males and females size (body length and width) and respective gonad length were smaller when reared with a non-cognate symbiotic species. Additionally, non-symbiotic bacteria did not sustain S. feltiae maturation to adult stages. Contrarily, S. carpocapsae juveniles developed to adults when reared with any of the bacterial conditions tested, including with non-symbiotic Serratia proteamaculans. Additionally, S. carpocapsae adults, unlike S. feltiae, did not exhibit enhanced body and gonad size when reared with their cognate symbiont. In fact, S. carpocapsae males and females had larger gonad lengths when reared with a non-cognate symbiotic strain, XnAna (X. nematophila associated with S. anatoliense). S. carpocapsae males and females had significantly underdeveloped gonads when reared with non-symbiotic bacteria. In both Steinernema spp., sex ratio was not impacted by the bacterial condition. However, sex ratio (female:male) S. carpocapsae, decreased from 2:1 to 1:1 when reared with non-symbiotic bacteria. The body and gonad sizes of Steinernema spp. reared in vitro with their cognate symbiont were significantly smaller than those grown in vivo. Ascaroside production in either Steinernema spp. was not significantly impacted by the rearing conditions. In S. carpocapsae, a significant increase in glucoside-1 was observed when the nematodes were reared with cognate or non-cognate bacteria. No detectable quantities of asc-C11 were produced by S. feltiae nematodes when reared with a non-cognate symbiotic bacterial species. We conclude that bacterial symbionts influenced maturation and development of first-generation adults’ in both Steinernema spp. tested in this study. However, response to the bacterial symbionts was species specific. Additionally, this study showed that Xenorhabdus as a food source plays an important role in the type and amount of ascarosides produced by Steinernema spp.
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Binagui-Casas, Anahi Liliana. "Analysis of the role of Flk-1 during mouse haematopoietic stem cell development." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31134.
Full textAbstract:
In the mouse embryo, the first definitive haematopoietic stem cells (HSCs), capable of repopulating adult irradiated mice, emerge at mid-gestation by embryonic day E11. At this stage, the aorta-gonad-mesonephros (AGM) region is able to initiate and expand HSCs. Recently, it has been shown that the development of HSC in the AGM region results from the maturation of haematopoietic precursors called pre-HSCs. Mounting evidence points at an endothelial origin for these cells, the haematogenic endothelium. Analysis of VEGFs mutants, a critical pathway for endothelial developement, suggested that it also plays a role during early haematopoiesis. The main receptor of the pathway, FLK-1 (also known as VEGRR2 or KDR), is expressed in early hematopoietic and endothelial cells in the mouse embryo. Knock-out mutants for Flk-1 showed a decrease of endothelial and intra-embryonic haematopoietic progenitors. Although Flk-1 has been identified as an essential gene for HSC emergence, its exact point of action in HSC development remains unknown. In this thesis, I investigated the role of FLK-1 signalling in haematopoietic development and defined precise stages and cell types during HSC emergence in which FLK-1 is critically involved. by using a reporter line and antibody staining, I demonstrated that FLK-1 is expressed in the pre-HSCs/HSC lineage. Germ-line Flk-1 knockout results in embryonic lethality at around E9.0, before HSC emergence, mainly due to defects in vasculogenesis. Since arterial specification precedes HSC formation, it has never been elucidated whether the haematopoietic defects found in the knockouts are a secondary effect of the loss of vasculature or it FLK-1 is directly involved in haematopoietic specification. Therefore, to determine the role of the receptor in HSC development, I used a conditional inducible mutagenesis approach that allowed the deletion of Flk-1 precisely when pre-HSCs mature into HSCs at E10.5 and E11.5. My data showed that Flk-1 deletion at these stages affects both endothelial and haematopoietic progenitors, as well as HSCs. This suggests that the VEGF pathway is not only essential in early stages of haematopoietic development, as previously demonstrated, but it may be also involved in the maturation of pre HSC into HSCs at later stages.
Books on the topic "Gonad development"
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Piprek, Rafal P., ed. Molecular Mechanisms of Cell Differentiation in Gonad Development. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-31973-5.
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Branch, Canada Dept of Fisheries and Oceans Gulf Region Science. Stages of gonad development in the sea scallop Placopecten magellanicus (Gmelin) based on both macroscopic and microscopic observation of the gametogenic cycle. Moncton, N.B: Dept. of Fisheries and Oceans, Science Branch, Gulf Region, 1989.
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Lau, Boulderson B. An evaluation of oocyte size in multiple regressions predicting gonad weight from body weight: A test using hawaiian ehu, Etelis carbunculus. [La Jolla, Calif.]: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, [Southwest Fisheries Science Center, 1994.
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Niehoff, Barbara. Gonadenentwicklung und Eiproduktion dreier Calanus-Arten (Copepoda): Freilandbeobachtungen, Histologie und Experimente = Gonad development and egg production of three Calanus species (Copepoda) : field observations, histology, and experiments. Bremerhaven: Alfred-Wegener-Institut für Polar- und Meeresforschung, 1996.
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1950-, Cowell Christopher T., Ho, Ken K. Y., 1950-, and Werther George A. 1948-, eds. Growth and sexual development. Chur, Switzerland: Harwood Academic Publishers, 1993.
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Piprek, Rafal P. Molecular Mechanisms of Cell Differentiation in Gonad Development. Springer, 2018.
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Piprek, Rafal P. Molecular Mechanisms of Cell Differentiation in Gonad Development. Springer, 2016.
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West, Lani. Prey selection by the tropical marine snail Thais melones: A study of the effects of interindividual variation and foraging experience on growth and gonad development. 1985.
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Sahay, Kamal Kishore. Development of Gond Tribes in Modern Perspectives. Classical Publishing Co.,India, 2005.
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G, Hillier S., and Workshop on the Development and Function of the Reproductive Organs (9th : 1992 : Peebles, Scotland), eds. Gonadal development and function. New York: Raven Press, 1992.
Find full textBook chapters on the topic "Gonad development"
1
Sharma, Shilpa, Anand Kumar, and Devendra K. Gupta. "Development of the Male Gonad." In Basics of Human Andrology, 67–76. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-3695-8_6.
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Van Doren, Mark. "Development of the Somatic Gonad and Fat Bodies." In Muscle Development in Drosophila, 51–61. New York, NY: Springer New York, 2006. http://dx.doi.org/10.1007/0-387-32963-3_5.
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Lajus, Dmitry L., and Victor R. Alekseev. "Fish: Diapause, Dormancy, Aestivation, and Delay in Gonad Development." In Dormancy in Aquatic Organisms. Theory, Human Use and Modeling, 53–69. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-21213-1_4.
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Grossman, Hadas, and Ruth Shalgi. "A Role of MicroRNAs in Cell Differentiation During Gonad Development." In Results and Problems in Cell Differentiation, 309–36. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-31973-5_12.
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Chiaverano, Luciano, Hermes Mianzan, and Fernando Ramìrez. "Gonad development and somatic growth patterns of Olindias sambaquiensis (Limnomedusae, Olindiidae)." In Coelenterate Biology 2003, 373–81. Dordrecht: Springer Netherlands, 2004. http://dx.doi.org/10.1007/978-1-4020-2762-8_43.
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Fujii, Haruhiko. "Gonad development of the sea anemone Anthopleura asiatica in clonal populations." In Coelenterate Biology: Recent Research on Cnidaria and Ctenophora, 527–32. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3240-4_74.
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Kumar, Prem, P. Behera, L. Christina, and M. Kailasam. "Sex Hormones and Their Role in Gonad Development and Reproductive Cycle of Fishes." In Recent updates in molecular Endocrinology and Reproductive Physiology of Fish, 1–22. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-8369-8_1.
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Tricas, Timothy C., and Joy T. Hiramoto. "Sexual differentiation, gonad development, and spawning seasonality of the Hawaiian butter fly fish, Chaetodon multicinctus." In The butterflyfishes: success on the coral reef, 111–24. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2325-6_8.
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Daniels, Carol D. "Gonads." In Encyclopedia of Child Behavior and Development, 706–7. Boston, MA: Springer US, 2011. http://dx.doi.org/10.1007/978-0-387-79061-9_1266.
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McKinlay, Rebecca, Peter O’Shaughnessey, Richard M. Sharpe, and Paul A. Fowler. "In Utero Exposure to Environmental Chemicals: Lessons from Maternal Cigarette Smoking and Its Effects on Gonad Development and Puberty." In Endocrine Disruptors and Puberty, 11–48. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-60761-561-3_2.
Full textConference papers on the topic "Gonad development"
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Muzaki, A., H. T. Yudha, N. A. Giri, Haryanti, and S. B. M. Sembiring. "GONAD DEVELOPMENT AND INITIAL SPAWNING OF SELECTED THIRD GENERATION CORAL TROUT (Plectropomus leopardus)." In International Conference on Fisheries and Aquaculture. The International Institute of Knowledge Management, 2022. http://dx.doi.org/10.17501/23861282.2021.7102.
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Bugaev, L. A., A. V. Voykina, and S. G. Sergeeva. "SPECIAL FEATURES OF OOCYTE SIZE IN SO-IUY MULLET (PLANILIZA HAEMATOCHEILA TEMMINCK & SCHLEGEL, 1845) IN THE SEA OF AZOV AT THE END OF THE WINTER SEASON, 2019." In STATE AND DEVELOPMENT PROSPECTS OF AGRIBUSINESS Volume 2. DSTU-Print, 2020. http://dx.doi.org/10.23947/interagro.2020.2.449-453.
Full textAbstract:
Analysis of special features of the reproductive system of so-iuy mullet Planiliza haematocheila (Temminck & Schlegel, 1845) females from the Azov and Black Sea Basin at the end of the winter season, 2019, has been conducted using the size of oocytes as its basis. Individual differences in distribution of oocyte sizes during the period of trophoplazmatic growth have been identified. Following the estimation of ordered series of oocyte sizes during the period of trophoplazmatic growth, the median and percentile values have been calculated; they can be used as reference values for qualitative characterization of ordered series for oocyte diameter in an individual specimen, using the empirical median, calculated for the respective specimen, as a basis. It has been found out that the sizes of trophoplazmatic growth oocytes, which are utilized during the spawning period of the current year, and, therefore, the degree of gonad maturity have individual characteristics independent of the age of an individual, of its length and weight, and of the content of reserve and bioactive substances in its tissues and blood.
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Kerans, Geterudis, and Bambang Retnoaji. "Artificial food effects on growth, survival and gonad development of Indonesian eel (Anguilla bicolor bicolor McClelland, 1844)." In THE 6TH INTERNATIONAL CONFERENCE ON BIOLOGICAL SCIENCE ICBS 2019: “Biodiversity as a Cornerstone for Embracing Future Humanity”. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0015705.
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Ataei, Abdol Hossain, and Figen Kırkpınar. "Application of In-Ovo Injection of Some Substances for Manipulation of Sex and Improving Performance in Chicken." In International Students Science Congress. Izmir International Guest Student Association, 2021. http://dx.doi.org/10.52460/issc.2021.006.
Full textAbstract:
In intensive production, freshly hatched cockerels are culled in the layer hatchery (7 billion males each year), On the other hand, for meat production rearing female birds has not economic benefits because of male broiler chicks have a faster growth rate and better feed efficiency than females. In this regards several methods are being developed for sex determination in the chick embryo during the incubation period. But these methods need to be rapid, cost-efficient, and suitable practical for commercial use. Additionally, sex determination should be done before pain perception has evolved in chick embryos. Biotechnology by in ovo technique to sex determination of between male and female chicks or sex reversal could improve production and eliminate ethical dilemmas for poultry industries. In birds, the differentiation of embryonic gonads is not determined by genetic gender with the certainty that occurs in mammals and can be affected by early treatment with a steroid hormone. During the development of the chick embryo, the genotype of the zygote determines the nature of the gonads, which then caused male or female phenotype. The differentiation of gonads during the period called the "critical period of sexual differentiation" is accompanied by the beginning of secretion of sexual hormones. Namely, any change in the concentration of steroid hormones during the critical period affects the structure of the gonads. Many synthetic anti-aromatases such as federazole and non-synthetic in plants, mushrooms, and fruits containing natural flavonoids have been used in the experiments in ovo injection of anti-aromatase had no negative effect on the growth performance of sexual reversal female chickens. In conclusion, administration of an aromatase inhibitor causes testicular growth in the genetic female gender, and estrogen administration leads to the production of the left ovotestis in the genetic male gender. Therefore, in the early stages of embryonic development, sexual differentiation can be affected by changing the ratio of sexual hormones. In this review, effects of some substances applied by in ovo injection technique on sex reversal and performance in chicks.
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Fulga, Nina, Laurentia Ungureanu, Dumitru Bulat, Denis Bulat, Ion Toderas, and Anatol Marta. "Morphohistological studies of the gonads of hybrid polyploid loach cobitis from the Lower Dniester." In Xth International Conference of Zoologists. Institute of Zoology, Republic of Moldova, 2021. http://dx.doi.org/10.53937/icz10.2021.16.
Full textAbstract:
In the lower Dniester, polyploid females of the hybrid complex Cobitis taenia are a portion spawning species with asynchronous development of germ cells during the entire breeding period. The spawning season in this water basin begins in the second decade of May and ends in July. In the population, in parallel with females, hermaphrodite individuals are also present, in which the ovary zone is functional, and the testis zone is sterile. A decrease in the relative mass of the gonads of subsequent generations was noted, which leads to a consistent decrease in the value of the gonadosomatic index, in females, before the second and third spawning.
Reports on the topic "Gonad development"
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Funkenstein, Bruria, and Cunming Duan. GH-IGF Axis in Sparus aurata: Possible Applications to Genetic Selection. United States Department of Agriculture, November 2000. http://dx.doi.org/10.32747/2000.7580665.bard.
Full textAbstract:
Many factors affect growth rate in fish: environmental, nutritional, genetics and endogenous (physiological) factors. Endogenous control of growth is very complex and many hormone systems are involved. Nevertheless, it is well accepted that growth hormone (GH) plays a major role in stimulating somatic growth. Although it is now clear that most, if not all, components of the GH-IGF axis exist in fish, we are still far from understanding how fish grow. In our project we used as the experimental system a marine fish, the gilthead sea bream (Sparus aurata), which inhabits lagoons along the Mediterranean and Atlantic coasts of Europe, and represents one of the most important fish species used in the mariculture industry in the Mediterranean region, including Israel. Production of Sparus is rapidly growing, however, in order for this production to stay competitive, the farming of this fish species has to intensify and become more efficient. One drawback, still, in Sparus extensive culture is that it grows relatively slow. In addition, it is now clear that growth and reproduction are physiological interrelated processes that affect each other. In particular sexual maturation (puberty) is known to be closely related to growth rate in fish as it is in mammals, indicating interactions between the somatotropic and gonadotropic axes. The goal of our project was to try to identify the rate-limiting components(s) in Sparus aurata GH-IGF system which might explain its slow growth by studying the ontogeny of growth-related genes: GH, GH receptor, IGF-I, IGF-II, IGF receptor, IGF-binding proteins (IGFBPs) and Pit-1 during early stages of development of Sparus aurata larvae from slow and fast growing lines. Our project was a continuation of a previous BARD project and could be divided into five major parts: i) obtaining additional tools to those obtained in the previous project that are necessary to carry out the developmental study; ii) the developmental expression of growth-related genes and their cellular localization; iii) tissue-specific expression and effect of GH on expression of growth-related genes; iv) possible relationship between GH gene structure, growth rate and genetic selection; v) the possible role of the IGF system in gonadal development. The major findings of our research can be summarized as follows: 1) The cDNAs (complete or partial) coding for Sparus IGFBP-2, GH receptor and Pit-1 were cloned. Sequence comparison reveals that the primary structure of IGFBP-2 protein is 43-49% identical to that of zebrafish and other vertebrates. Intensive efforts resulted in cloning a fragment of 138 nucleotides, coding for 46 amino acids in the proximal end of the intracellular domain of GH receptor. This is the first fish GH receptor cDNA that had been cloned to date. The cloned fragment will enable us to complete the GH - receptor cloning. 2) IGF-I, IGF-II, IGFBP-2, and IGF receptor transcripts were detected by RT-PCR method throughout development in unfertilized eggs, embryos, and larvae suggesting that these mRNAs are products of both the maternal and the embryonic genomes. Preliminary RT-PCR analysis suggest that GH receptor transcript is present in post-hatching larvae already on day 1. 3) IGF-1R transcripts were detected in all tissues tested by RT-PCR with highest levels in gill cartilage, skin, kidney, heart, pyloric caeca, and brain. Northern blot analysis detected IGF receptor only in gonads, brain and gill cartilage but not in muscle; GH increased slightly brain and gill cartilage IGF-1R mRNA levels. 4) IGFBP-2 transcript were detected only in liver and gonads, when analyzed by Northern blots; RT-PCR analysis revealed expression in all tissues studied, with the highest levels found in liver, skin, gonad and pyloric caeca. 5) Expression of IGF-I, IGF-II, IGF-1R and IGFBP-2 was analyzed during gonadal development. High levels of IGF-I and IGFBP-2 expression were found in bisexual young gonads, which decreased during gonadal development. Regardless of maturational stage, IGF-II levels were higher than those of IGF-L 6) The GH gene was cloned and its structure was characterized. It contains minisatellites of tandem repeats in the first and third introns that result in high level of genetic polymorphism. 7) Analysis of the presence of IGF-I and two types of IGF receptor by immunohistochemistry revealed tissue- and stage-specific expression during larval development. Immunohistochemistry also showed that IGF-I and its receptors are present in both testicular and ovarian cells. Although at this stage we are not able to pinpoint which is the rate-limiting step causing the slow growth of Sparus aurata, our project (together with the previous BARD) yielded a great number of experimental tools both DNA probes and antibodies that will enable further studies on the factors regulating growth in Sparus aurata. Our expression studies and cellular localization shed new light on the tissue and developmental expression of growth-related genes in fish.
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Yaron, Zvi, Abigail Elizur, Martin Schreibman, and Yonathan Zohar. Advancing Puberty in the Black Carp (Mylopharyngodon piceus) and the Striped Bass (Morone saxatilis). United States Department of Agriculture, January 2000. http://dx.doi.org/10.32747/2000.7695841.bard.
Full textAbstract:
Both the genes and cDNA sequences encoding the b-subunits of black carp LH and FSH were isolated, cloned and sequenced. Sequence analysis of the bcFSHb and LHb5'flanking regions revealed that the promoter region of both genes contains canonical TATA sequences, 30 bp and 17 bp upstream of the transcription start site of FSHb and LHb genes, respectively. In addition, they include several sequences of cis-acting motifs, required for inducible and tissue-specific transcriptional regulation: the gonadotropin-specific element (GSE), GnRH responsive element (GRE), half sites of estrogen and androgen response elements, cAMP response element, and AP1. Several methods have been employed by the Israeli team to purify the recombinant b subunits (EtOH precipitation, gel filtration and lentil lectin). While the final objective to produce pure recombinantGtH subunits has not yet been achieved, we have covered much ground towards this goal. The black carp ovary showed a gradual increase in both mass and oocyte diameter. First postvitellogenic oocytes were found in 5 yr old fish. At this age, the testes already contained spermatozoa. The circulating LH levels increased from 0.5 ng/ml in 4 yr old fish to >5ng/ml in 5 yr old fish. In vivo challenge experiments in black carp showed the initial LH response of the pituitary to GnRH in 4 yr old fish. The response was further augmented in 5 yr old fish. The increase in estradiol level in response to gonadotropic stimulation was first noted in 4 yr old fish but this response was much stronger in the following year. In vivo experiments on the FSHb and LHb mRNA levels in response to GnRH were carried out on common carp as a model for synchronom spawning cyprinids. These experiments showed the prevalence of FSHP in maturing fish while LHP mRNA was prevalent in mature fish, especially in females. The gonadal fat-pad was found to originate from the retroperitoneal mesoderm and not from the genital ridge, thus differing from that reported in certain amphibians This tissue possibly serves as the major source of sex steroids in the immature black carp. However, such a function is taken over by the developing gonads in 4 yr old fish. In the striped bass, we described the ontogeny of the neuro-endocrine parameters along the brain-pituitary-gonadal axis during the first four years of life, throughout gonadal development and the onset of puberty. We also described the responsiveness of the reproductive axis to long-term hormonal manipulations at various stages of gonadal development. Most males reached complete sexual maturity during the first year of life. Puberty was initiated during the third year of life in most females, but this first reproductive cycle did not lead to the acquisition of full sexual maturity. This finding indicates that more than one reproductive cycle may be required before adulthood is reached. Out of the three native GnRHs present in striped bass, only sbGnRH and cGnRH II increased concomitantly with the progress of gonadal development and the onset of puberty. This finding, together with data on GtH synthesis and release, suggests that while sbGnRH and cGnRH II may be involved in the regulation of puberty in striped bass, these neuropeptides are not limiting factors to the onset of puberty. Plasma LH levels remained low in all fish, suggesting that LH plays only a minor role in early gonadal development. This hypothesis was further supported by the finding that experimentally elevated plasma LH levels did not result in the induction of complete ovarian and testicular development. The acquisition of complete puberty in 4 yr old females was associated with a rise in the mRNA levels of all GtH subunit genes, including a 218-fold increase in the mRNA levels of bFSH. mRNA levels of the a and PLH subunits increased only 11- and 8-fold, respectively. Although data on plasma FSH levels are unavailable, the dramatic increase in bFSH mRNA suggests a pivotal role for this hormone in regulating the onset and completion of puberty in striped bass. The hormonal regulation of the onset of puberty and of GtH synthesis and release was studied by chronic administration of testosterone (T) and/or an analog of gonadotropin-releasing hormone (G). Sustained administration of T+G increased the mRNA levels of the PLH subunit to the values characteristic of sexually mature fish, and also increased the plasma levels of LH. However, these changes did not result in the acceleration of sexual maturation. The mRNA levels of the bFSH subunit were slightly stimulated, but remained about 1/10 of the values characteristic of sexually mature fish. It is concluded that the stimulation of FSH gene expression and release does not lead to the acceleration of sexual maturity, and that the failure to sufficiently stimulate the bFSH subunit gene expression may underlie the inability of the treatments to advance sexual maturity. Consequently, FSH is suggested to be the key hormone to the initiation and completion of puberty in striped bass. Future efforts to induce precocious puberty in striped bass should focus on understanding the regulation of FSH synthesis and release and on developing technologies to induce these processes. Definite formulation of hormonal manipulation to advance puberty in the striped bass and the black carp seems to be premature at this stage. However, the project has already yielded a great number of experimental tools of DNA technology, slow-release systems and endocrine information on the process of puberty. These systems and certain protocols have been already utilized successfully to advance maturation in other fish (e.g. grey mullet) and will form a base for further study on fish puberty.