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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 21 to 25 of 25 (0.038 seconds)| 21 |
Organ and primary culture of medaka (Oryzias latipes) testis: Test systems for the analysis of cell proliferation and differentiation / Organ und Primärzellkultur von Medaka Testis: Test Systeme zur Untersuchung des Zellproliferation und ZelldifferenzierungSong, Miyeoun 22 June 2003 (has links) (PDF)
In cultured medaka testis fragments, cells remained viable for the entire culture period (17h), and spermatids that developed from spermatocytes were viable and motile. Primary cultures were characterized over a period of two days with respect to cell viability and the distribution of adherent and suspended cells. These two cell populations were maintained in dynamic equilibrium in vitro for several days. Proliferating cells were predominant among clusters of suspended cells, as determined by BrdU labeling, and CFSE and propidium iodide PI labeling. Based on cytological criteria, the proliferating cells were mostly spermatogonia and possibly also preleptotene spermatocytes. Differentiation of spermatocytes into spermatids or spermatozoa was also observed, mainly among the suspended cells. These results suggest that the organ and primary culture systems are suitable systems for studying the effects of substances that interfere with spermatogenesis in the medaka, a model vertebrate. The organ and primary culture systems were used to analyze the effects of a synthetic estrogen, EE2, on cell proliferation in medaka testis. Both organ and primary culture were suitable for this purpose consistently small concentrations (0.01 and 1 nM) of EE2 stimulated cell proliferation slightly, while higher concentrations (100 nM) had an inhibitory effect. To investigate the effect of phytoestrogens on cell proliferation in spermatogenesis, selected flavonoids [genistein (1, 10, 100 µg/ml), quercetin (0.01, 1, 100 µM), and 8-prenylnarigenin (0.001, 0.1, 1, 10 µM)] were added to medaka testis primary cultures. Genistein and quercetin inhibited cell proliferation in the cultures while 8-prenylnarigenin had no effect. In a second series of experiments the addition of genistein (10 µg/ml) to primary cultures significantly inhibited both cell proliferation and cell differentiation as determined by flow cytometry using CFSE/PI labeling.
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Novel proapoptotic p63 isoforms are driven by an endogenous retrovirus in the male germ line of humans and great apes, likely increasing genome stability / Neue proapoptotische p63-Isoformen werden von einem endogenen Retrovirus in den männlichen Keimbahnen von Mensch und Menschenaffen gesteuert und erhöhen wahrscheinlich die genomische StabilitätBeyer, Ulrike 29 October 2010 (has links)
No description available.
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Tunable Protein Stabilization In Vivo Mediated by Shield-1 in Transgenic Medaka: Research ArticleFroschauer, Alexander, Kube, Lisa, Kegler, Alexandra, Rieger, Christiane, Gutzeit, Herwig O. 07 January 2016 (has links)
Techniques for conditional gene or protein expression are important tools in developmental biology and in the analysis of physiology and disease. On the protein level, the tunable and reversible expression of proteins can be achieved by the fusion of the protein of interest to a destabilizing domain (DD). In the absence of its specific ligand (Shield-1), the protein is degraded by the proteasome. The DD-Shield system has proven to be an excellent tool to regulate the expression of proteins of interests in mammalian systems but has not been applied in teleosts like the medaka. We present the application of the DD-Shield technique in transgenic medaka and show the ubiquitous conditional expression throughout life. Shield-1 administration to the water leads to concentration-dependent induction of a YFP reporter gene in various organs and in spermatogonia at the cellular level.
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Organ and primary culture of medaka (Oryzias latipes) testis: Test systems for the analysis of cell proliferation and differentiationSong, Miyeoun 18 July 2003 (has links)
In cultured medaka testis fragments, cells remained viable for the entire culture period (17h), and spermatids that developed from spermatocytes were viable and motile. Primary cultures were characterized over a period of two days with respect to cell viability and the distribution of adherent and suspended cells. These two cell populations were maintained in dynamic equilibrium in vitro for several days. Proliferating cells were predominant among clusters of suspended cells, as determined by BrdU labeling, and CFSE and propidium iodide PI labeling. Based on cytological criteria, the proliferating cells were mostly spermatogonia and possibly also preleptotene spermatocytes. Differentiation of spermatocytes into spermatids or spermatozoa was also observed, mainly among the suspended cells. These results suggest that the organ and primary culture systems are suitable systems for studying the effects of substances that interfere with spermatogenesis in the medaka, a model vertebrate. The organ and primary culture systems were used to analyze the effects of a synthetic estrogen, EE2, on cell proliferation in medaka testis. Both organ and primary culture were suitable for this purpose consistently small concentrations (0.01 and 1 nM) of EE2 stimulated cell proliferation slightly, while higher concentrations (100 nM) had an inhibitory effect. To investigate the effect of phytoestrogens on cell proliferation in spermatogenesis, selected flavonoids [genistein (1, 10, 100 µg/ml), quercetin (0.01, 1, 100 µM), and 8-prenylnarigenin (0.001, 0.1, 1, 10 µM)] were added to medaka testis primary cultures. Genistein and quercetin inhibited cell proliferation in the cultures while 8-prenylnarigenin had no effect. In a second series of experiments the addition of genistein (10 µg/ml) to primary cultures significantly inhibited both cell proliferation and cell differentiation as determined by flow cytometry using CFSE/PI labeling.
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Transcriptomes of testis and pituitary from male Nile tilapia (O. niloticus L.) in the context of social statusThönnes, Michelle, Prause, Rebecca, Levavi-Sivan, Berta, Pfennig, Frank 18 April 2024 (has links)
African cichlids are well established models for studying social hierarchies in teleosts and elucidating the effects social dominance has on gene expression. Ascension in the social hierarchy has been found to increase plasma levels of steroid hormones, follicle stimulating hormone (Fsh) and luteinizing hormone (Lh) as well as gonadosomatic index (GSI). Furthermore, the expression of genes related to gonadotropins and steroidogenesis and signaling along the brain-pituitary-gonad axis (BPG-axis) is affected by changes of an animal’s social status. In this study, we use RNA-sequencing to obtain an in-depth look at the transcriptomes of testes and pituitaries from dominant and subordinate male Nile tilapia living in long-term stable social hierarchies. This allows us to draw conclusions about factors along the brain-pituitary-gonad axis that are involved in maintaining dominance over weeks or even months. We identify a number of genes that are differentially regulated between dominant and subordinate males and show that in high-ranking fish this subset of genes is generally upregulated. Genes differentially expressed between the two social groups comprise growth factors, related binding proteins and receptors, components of Wnt-, Tgfβ- and retinoic acid-signaling pathway, gonadotropin signaling and steroidogenesis pathways. The latter is backed up by elevated levels of 11-ketotestosterone, testosterone and estradiol in dominant males. Luteinizing hormone (Lh) is found in higher concentration in the plasma of long-term dominant males than in subordinate animals. Our results both strengthen the existing models and propose new candidates for functional studies to expand our understanding of social phenomena in teleost fish.
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