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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the 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.
51

Changes in Gene Expression of Goat Developing Testes and Sperm During Breeding and Non-breeding Season

Faucette, Azure 2012 May 1900 (has links)
Testicular function is fundamental to male fertility, since testicular cells act in collaboration with each other to signal sex differentiation, the initiation of puberty and spermatogenesis. Complications that can be influenced by many factors will affect sperm number, morphology, motility, chromatin quality and acrosomal integrity. The purpose of these studies was to analyze the changes in gene expression in the developing testes and analyze the seasonal changes in gene products in sperm of mature bucks. In the first experiment, testes were harvested from five Alpine bucks at 0, 2, 4, 6, and 8 months of age. Northern and in situ hybridization indicated that the largest change in gene expression occurred during the first 4 months of goat testes development. Sex determining region Y-box 9 (SOX9) and Heat Shock protein A8 (HSPA8) peaked at 2 months of age, and were expressed in Sertoli cells and spermatogonium, respectively. At 4 months, expression of Stimulated by Retinoic Acid gene 8 (STRA8), Protamine1 (PRM1) and Outer Dense Fiber protein 2 (ODF2) was strongly up-regulated in early and maturing germ cells, respectively. In the second experiment, RNA from ejaculated spermatozoa collected from mature Alpine bucks in peak (October) and non-peak (April) breeding season were analyzed on a 4 x 44K Agilent bovine microarray. One thousand three hundred and eighteen gene products were differentially expressed 2-fold or more (p ≤ 0.05 ) was expressed in mature goat sperm collected October and April. To eliminate the likelihood of false positives, the cut off was set to fold change of 3 or more at p ≤ 0.01 which narrowed the list of genes to 50 transcripts. Real time PCR results confirmed the expression of Sperm Adhesion Molecule 1 (SPAM1) in April, and the expression of Glycerol kinase 2(GK2) and Myc Binding Protein 2 (MYCBP2) in October. Based on the results from both experiments, it can be concluded that: SOX9 and HSPA8 expression play an important role in tubular formation and germ cell maintenance; two months after SOX9 and HSPA8 expression, genes that are associated with spermatogenesis initiation and completion are upregulated; and validation of the seasonal changes in sperm mRNA levels may provide additional insight to testicular events as they relate to breeding and non-breeding season.
52

Different Mechanisms are Involved in 3H-Androgen Uptake by the Rat Seminiferous and Epididymal Tubules in vivo

MIYAKE, KOJI, NAGAI, TATSUYA, YAMAMOTO, MASANORI 03 1900 (has links)
No description available.
53

Role of cytokines in the regulation of cell junction dynamics in the testis

Gao, Ying, 高莹 January 2013 (has links)
During spermatogenesis, developing germ cells must migrate across the blood-testis barrier (BTB) and enter the adluminal compartment for further development. Throughout this process, extensive junction restructuring occurs at Sertoli-Sertoli and Sertoli-germ cell interfaces. Cytokines are known to play crucial roles in regulating testicular cell junction dynamics at different regulatory levels. However, the mechanism of cytokine-mediated regulation on newly identified junction molecules remains unclear. In this dissertation, the molecular mechanisms on how cytokines regulate the junction proteins of immunoglobulin superfamily (IgSF) including coxsackievirus and adenovirus receptor (CAR), nectin-like molecule-2 (Necl-2) and Necl-4 in testicular cells were studied. CAR is expressed on Sertoli and germ cells. It mediates both homophilic and heterophilic interaction for Sertoli-germ cell adhesion. It was found that combined treatment of interferon-γ (IFN-γ) and tumor necrosis factor α (TNFα) reduced CAR mRNA and protein levels, and caused the disappearance of CAR from germ cell interface. IFN-γ+TNFα promoted CAR protein degradation via ubiquitin-proteasome pathway. In addition, IFN-γ+TNFα reduced CAR mRNA through regulating the binding of NF-κB subunits and SP/KLF proteins to CAR promoter. Collectively, these results demonstrated for the first time the potential mechanism utilized by IFN-γ+TNFα to exert their effects during testicular inflammation. Necl-2 is exclusively expressed by spermatogenic cells in the testis. In this study, it was demonstrated that transforming growth factor-β1 (TGF-β1) down-regulated Necl-2 mRNA and protein levels, and caused the disappearance of Necl-2 from cell surface. Using inhibitors and shRNAs, it was found that TGF-β1 induced Necl-2 protein degradation through clathrin-dependent endocytosis. Endocytosis assay further confirmed that TGF-β1 accelerated the internalization of Necl-2 to cytosol. Moreover, TGF-β1 repressed Necl-2 gene transcription in Smad-dependent manner. Taken together, these results unraveled the mechanism of how TGF-β1 regulates Necl-2 expression to achieve timely junction restructuring during spermatogenesis. Necl-4 has been detected in Sertoli cells, but little is known about its regulation in the testis. It was found that TNFα down-regulated Necl-4 mRNA and protein levels. Inhibitor studies suggested that both caveolin-dependent endocytosis and ubiquitin-proteasome pathway were involved in TNFα-induced Necl-4 protein degradation. Co-immunoprecipitation indicated that Necl-4 was physically associated with Par3, Par6, aPKC and Cdc42 which are the major components of polarity complex in mouse testis. Further study was shown that TNFα reduced the expression of Par3, and altered the binding between Necl-4 and Par complex in Sertoli cells. These results suggested that Necl-4-mediated cell adhesion could be disrupted by TNFα via reducing its expression and altering its interaction with Par complex. Studies reported herein suggest that junction proteins of the IgSF are precisely regulated by cytokines at transcriptional and post-translational levels. These results further enrich current understanding on how junction dynamics are regulated during spermatogenesis. / published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy
54

Regulation of gonadotropin receptors in the testis of the adult ram

Baker, Susan Jane. January 1987 (has links)
Factors influencing testicular gonadotropin receptors and testis responsiveness to luteinizing hormone (LH) stimulation were studied during the seasonal sexual cycle of the adult ram. The normal variation in testis content of gonadotropin receptors was mapped out in relation to changes in (1) testis size, (2) testis responsiveness to LH stimulation and (3) mean serum concentration of LH, follicle stimulating hormone (FSH), testosterone and prolactin (PRL). The increase in gonadotropin receptor numbers during testicular redevelopment was preceded by elevated serum concentrations of PRL and associated with increases in both the frequency of endogenous pulses of LH and the responsiveness of the testis to LH stimulation. When serum PRL concentrations displayed abnormal variations in relation to photoperiod, the normal patterns of change in testis LH receptors and responsiveness to LH stimulation were altered. To determine if the increase in gonadotropin receptors was due to increased frequency of LH pulses up regulating homologous receptors, rams were injected, in the nonbreeding season with small, frequent doses of LH. Testis responsiveness was greatly enhanced but occurred independently of changes in gonadotropin receptor numbers or their binding affinities. To determine if the seasonal rise in serum PRL concentration was influencing gonadotropin receptors, endogenous secretion was suppressed by treatment with 2-bromo-X-ergocryptine (CB154) prior to and during testicular redevelopment. This resulted in delayed testicular redevelopment and reduced numbers of testicular LH receptors. Reduced numbers of LH receptors was associated with reduced responsiveness of the testis to LH stimulation. These results support the hypothesis that the seasonal increase in serum PRL concentration initiates testicular redevelopment by increasing LH receptors. Increases in LH peak frequency enhance responsiveness but this occurs independently of changes in gonadotropin receptors.
55

The molecular identity of soluble adenylyl cyclase /

Farrell, Jeanne. January 2008 (has links)
Thesis (Ph. D.)--Cornell University, May, 2008. / Vita. Includes bibliographical references (leaves 133-142).
56

Characterization and regulation of expression of tyrosine kinase receptors rse, axl, mer and their ligand gas6 in the testis /

Chan, Chi-wai, Michael. January 1998 (has links)
Thesis (M. Phil.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 75-82).
57

Actin associated intercellular adhesion junctions in the mammalian testis

Pfeiffer, David Carl January 1990 (has links)
In the mammalian seminiferous epithelium, the cytoplasm of Sertoli cells adjacent to sites of intercellular attachment exhibits unique structural attributes. In each of these regions, a layer of hexagonally packed actin filaments lies situated between a cistern of endoplasmic reticulum and the plasma membrane. The filament layer together with the reticulum and adjacent plasma membrane are collectively termed an "ectoplasmic specialization". Ectoplasmic specializations occur in apical Sertoli cell regions at sites of attachment to spermatids and basally at sites of attachment to adjacent Sertoli cells. Ectoplasmic specializations have been hypothesized to be actin associated intercellular adhesion junctions. If this is true, molecular components that characterize actin associated adhesion junctions in general should be present in ectoplasmic specializations. In this study, I tested this prediction in two ways. First, I investigated whether or not the protein vinculin is co-distributed with actin filament bundles in ectoplasmic specializations of the ground squirrel. Second, I immunologically probed ectoplasmic specializations for three cell adhesion molecules (CAMs) that are commonly found in regions of intercellular adhesion in other tissues. My results indicate that vinculin is co-distributed with actin in Sertoli cell regions attached to spermatids. These data are consistent with the conclusion that vinculin is a component of ectoplasmic specializations and, therefore, with the hypothesis that the latter structures are a form of actin associated adhesion junction. Experiments using probes for the CAMs indicate that E-cadherin, A-CAM and N-CAM are probably not present in ectoplasmic specializations. The adhesion molecule at these sites may be a different member of the known CAMs or an as yet unidentified CAM. Based on data presented here and elsewhere indicating that ectoplasmic specializations are a form of actin associated adhesion junction, I describe the elaborate changes that occur in constituent filament bundles at sites of attachment to spermatids of the ground squirrel and interprete them in the context of the adhesion hypothesis. During the course of the co-localization studies described above, I observed that vinculin and actin are co-distributed at certain sites of intercellular attachment between interstitial cells of Leydig in the ground squirrel testis. Moreover, at the ultrastructural level I found these sites correspond to microfilament rich junction regions. These observations are consistent with the conclusion that actin associated intercellular adhesion junctions exist between interstitial cells of Leydig in the ground squirrel testis. / Medicine, Faculty of / Graduate
58

Prävalenz von Hydatiden als Begleitpathologie bei Maldescensus testis : Eine retrospektive Datenanalyse der operativen Eingriffe der kinderchirurgischen Abteilung der Universitätsklinik Würzburg im Zeitraum von 2010 bis einschließlich 2015 / Coincidence of hydatid of Morgagni and undescended testis

Geiselmann, David January 2021 (has links) (PDF)
Im Rahmen einer retrospektiven Datenanalyse über einen Zeitraum von 6 Jahren wurde an Hand von 814 operierten Hoden die Koinzidenz eines Maldescensus testis mit einer Morgagni-Hydatide untersucht. Dabei ergab sich eine Hydatidengesamtprävalenz bei erfolgter Hodenhülleneröffnung nicht-deszendierter Hoden von 62,66 %. Zusätzlich konnten wir eine Korrelation zwischen Patientenalter und Größenausprägung der Hydatiden feststellen. Entsprechend der Studienergebnisse kann die Vermutung geäußert werden, dass von einer Größenwachstumsdynamik der Hydatiden – am ehesten unter Hormoneinfluss – in Bezug zum Patientenalter ausgegangen werden kann. / As part of a retrospective data analysis over a period of 6 years, the coincidence of undescended testis and hydatid of Morgagni (appendix testis) was examined on the basis of 814 operated testes. The overall prevalence of hydatids after opening of the testicular envelope of undescended testes was 62.66%. In addition, we were able to establish a correlation between patient age and the hydatid size. According to the results of the study, the size of the hydatid-with growth most likely to be influenced by hormones-can be assumed to be associated with the patient's age.
59

Regulation of gonadotropin receptors in the testis of the adult ram

Baker, Susan Jane January 1987 (has links)
No description available.
60

Age-related changes in the cat testis and epididymis

Elcock, Laura Elise Hart January 2011 (has links)
Digitized by Kansas Correctional Industries

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