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Conserved Variation in Tandem Repeat Sequences Tunes the Self-Assembly and Stability Characteristics of the Staphylococcus epidermidis Biofilm Protein AapShelton, Catherine L. 10 October 2016 (has links)
No description available.
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Investigation of RNA Structural Motifs in a Viroid Required for Its Intercellular Trafficking and Characterization of a Plant RNA Ligase Essential for Viroid ReplicationTakeda, Ryuta 17 March 2011 (has links)
No description available.
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Examining Cellular Interactions and Response to Chemotherapy in The Glioblastoma Perivascular NicheHatlen, Rosalyn Rae 17 January 2023 (has links)
Glioblastoma multiforme (GBM) is the most deadly and common form of brain cancer and is responsible for over 50% of adult brain tumors. A specific region within the GBM environment is known as the perivascular niche (PVN). We have designed a 3D in vitro model of the PVN comprised of either collagen Type 1 or HyStem-C®, human umbilical vein endothelial cells (HUVECs) or human brain microvascular endothelial cells (HBMECs), and LN229 (GBM) cells. A synergistic response between HUVECs and LN229 cells was observed in co-culture, including 10 – 16-fold increased cell proliferation, a decrease in the height of hydrogels of up to 68%, as well as elevated secretion of TGF-β and CXCL12 up to 2.6-fold from Day 8 to 14. These trends correlated with cell colocalization, indicating a chemotactic role for CXCL12 in enabling the migration of LN229 cells towards HUVECs in co-cultures. Von Willebrand factor (vWF) was co-expressed with glial fibrillary acidic protein (GFAP) in up to 40% of LN229 cells after 14 days in co-culture in collagen (2.2 mg/mL) and HyStem-C® gels. The expression of vWF indicates the early stages of trans-differentiation of LN229 cells to an endothelial cell phenotype. We then investigated the effect of chemotherapeutic drugs temozolomide (TMZ) and Avastin® on EC networks, LN229 cell morphology and alignment, cytotoxicity, colocalization, and trans-differentiation. TMZ was observed to primarily affect LN229 cells, with treatment at high concentrations resulting in up to 2.3-fold reduced alignment as well as an increase in cell circularity. Cytotoxicity of up to 94% was also observed up to in LN229 monocultures, and was significantly higher in collagen (1.1 mg/mL) gels. Avastin® treatment resulted in changes to ECs. Network features were significantly reduced and EC cellular proliferation decreased up to 69% with Avastin® treatment. Significant increases in percentages of colocalized and GFAP+/vWF+ cells were also observed when treated with 8 µg/mL Avastin®. This suggests that chemotactic signaling may have been altered. TGF-β secretion was reduced in co-cultures when 150 µM TMZ or 8 µg/mL Avastin® were administered. / Doctor of Philosophy / Glioblastoma (GBM) is the most common and deadly form of brain cancer and is responsible for over 50% of adult brain tumors. A specific region within the GBM environment of particular interest is located near the vasculature, known as the perivascular niche (PVN). We have designed a 3D in vitro model of the PVN consisting of either collagen type 1 or HyStem-C®, a material made of primarily hyaluronic acid. Human umbilical vein endothelial cells (HUVECs), an immortalized cell line, or primary human brain microvascular endothelial cells (HBMECs) as well as LN229 (GBM) cells were used. A synergistic response was observed between HUVECs and LN229 cells in co-culture, including changes to the extracellular matrix, and signaling factor secretion. Further supporting this data, colocalization between LN229 cells and HUVECs was observed. Colocalization is a phenomenon where two cell types come into physical contact after one moves toward another. This indicated preferential migration, specifically in response to CXCL12. Endothelial cell marker von Willebrand factor (vWF) was co-expressed with glial fibrillary acidic protein (GFAP), commonly used to identify GBM cells. This percentage was increased in co-cultures with HBMECs, pointing to differences in the response of primary cells to immortalized cell lines. The expression of vWF indicates the early stages of trans-differentiation of LN229 cells to an endothelial cell phenotype. We then investigated the effect of chemotherapeutic drugs temozolomide (TMZ) and Avastin® in the PVN model. TMZ was observed to primarily affect LN229 cells, by reducing their alignment as well as causing cell death. Avastin® treatment resulted in changes to ECs. Networks and cell growth were significantly reduced after Avastin® treatment. When either TMZ or Avastin® was administered, the secretion of TGF-β, was reduced.
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Probing Endothelial-to-Mesenchymal Transition Cellular BiomechanicsMendoza, Marvin A, Jr 01 January 2024 (has links) (PDF)
Endothelial-to-mesenchymal transition (EndMT) is a dynamic, biological process in which endothelial cells (ECs) suppress fundamental endothelial properties and adopt mesenchymal characteristics such as the loss of cell-cell contacts, an increase in migratory potential, and increased contractility. Although this trans-differentiation program is recognized as essential for development and vascular homeostasis there is rising evidence of its incidence in vascular pathological conditions, particularly atherosclerosis, venous disease, and varicose veins. Therapeutic targeting of EndMT appears promising but in-vitro EndMT studies face numerous hurdles including the lack of standardized experimental models and the dynamic nature of endothelial plasticity. This study aims to directly quantify the physical forces behind EndMT progression to identify a mechanophenotype. To address these challenges, we performed immunofluorescence imaging of endothelial and mesenchymal-specific markers, morphological analysis, and measured tractions and intercellular stresses of venous endothelial cells exposed to TGF-β1, a known EndMT inducer, at 24, 48, and 72 hours. Interestingly, our time-point analysis revealed a decrease in tractions and intercellular stresses and increase in cell area and eccentricity at 24 hours followed by a decrease in endothelial markers and increase in mesenchymal markers via immunofluorescence at 48 and 72 hours. Additionally, our results revealed EndMT to occur gradually, with most cells progressing to an intermediate phenotype, however, a subpopulation of cells progressed to a more complete mesenchymal phenotype and prompted us to investigate the mechanics at the single-cell level. Our single-cell results revealed TGF-β1 treated cells yielded a 1.65-fold increase in tractions compared to control cells. The mechanics-oriented focus of this study is unique and complimentary to standard biochemical and molecular strategies used to study EndMT, which can offer new perspectives for innovative therapeutic interventions for endothelial dysfunction and vascular disease.
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Význam rostlinných proteinů z podrodiny ABCB pro transport auxinu / Význam rostlinných proteinů z podrodiny ABCB pro transport auxinuKubeš, Martin January 2011 (has links)
Polar auxin transport provides essential directional and positional information for many developmental processes in plants. At the cellular level, it is realized by both passive diffusion and the active transport through the membrane proteins - AUX1/LAXes, PINs and ABCBs. The aim of this thesis was to characterize the role of ABCB1, ABCB4 and ABCB19 proteins in polar auxin transport using transformed tobacco BY-2 cell lines. It was shown that the plasma membrane (PM) localization of the ABCB1, 4 and 19 is not polar. The ABCB4 was also more stable on PM after the treatment with auxin influx inhibitors; making use of ABCB4-cell line helped to uncover new characteristics of markers of endocytosis - the FM- dyes. The induction of ABCB19 has led to a decrease in 3 H-NAA accumulation with characteristic auxin starvation phenotype, similar to PIN7 overexpressing cell line, that could be rescued in case of PIN7 cell line by application of the auxin efflux inhibitor NPA; however, the accumulation of auxin in ABCB19-overexpressing cell line was less sensitive to NPA and the rescue of the auxin starvation phenotype was ineffective. Importantly, unique property of the ABCB4 was demonstrated: It displayed dual, auxin-concentration-dependent auxin transport activity in Arabidopsis roots, tobacco BY-2 and yeast cells. The...
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Avaliação do papel da conexina 43 no desenvolvimento do granuloma, experimentalmente induzido em camundongos / Evaluation of the role of connexin 43 in the development of granuloma, experimentally induced in miceOloris, Silvia Catarina Salgado 22 July 2005 (has links)
A doença granulomatosa inflamatória envolve interações coordenadas entre linfócitos, monócitos/macrófagos, células epitelióides, eosinófilos, neutrófilos e fibroblastos. A comunicação intercelular mediada por junções gap, constituídas por conexinas, é responsável pela homeostase tecidual. A Cx43 está presente em células linfóides, células mielóides, fibroblastos e outras. Assim, para compreendermos o possível envolvimento das conexinas no granuloma, nós analisamos o efeito da deleção heterozigótica de uma Gja1 (gene Cx43) na formação e desenvolvimento dos granulomas hepáticos, induzidos por ovos de Schistosoma mansoni. Para tanto, camundongos heterozigotos (Cx43+/-) e selvagens (Cx43+/+) foram infectados com cercárias de Schistosoma mansoni e avaliados nos tempos: 6, 8 e 12 semanas após a infecção. As células dos granulomas apresentaram expressão de conexina 43, notadamente após 12 semanas de infecção. As lesões dos camundongos Cx43+/- apresentaram índice de proliferação reduzido e aumento na deposição de colágeno em fases tardias da doença. Apesar desses achados, não se encontrou redução no tamanho e celularidade das lesões em comparação aos camundongos selvagens. Também não obtivemos diferenças em relação ao hemograma ou população de linfócitos esplênicos CD4, CD8 e CD19. As células peritoneais dos animais de ambos genótipos apresentaram produção de NO e H<SUB2O<SUB2 similares. Contudo, os neutrófilos e monócitos sanguíneos dos animais Cx43+/-, estimulados por PMA, apresentaram aumento significante do burst oxidativo. Concluindo, nossos resultados indicam que a deleção de um alelo do gene da Cx43 modifica claramente a evolução da doença granulomatosa, mostrando um papel desta conexina no desenvolvimento do granuloma. / Inflammatory granulomatous disease involves coordinated interactions among lymphocytes, monocytes/macrophages, epithelioid cells, eosinophils, neutrophils and fibroblasts. Intercellular communication mediated by gap junctions constituted of connexins, is responsible for tissue homeostasis. Cx43 is present in lymphoid cells, myelogenous cells, fibroblasts and others. In order to understand the possible involvement of connexins in granuloma, we analyzed the effect of the heterologous deletion of a Gja1 (Cx43 gene) on the formation and development of hepatic granulomas induced by Schistosoma mansoni eggs. Heterozigous (Cx43+/-) and wild-type (Cx43+/+) mice were infected with S. mansoni cercarie and evaluated after 6, 8 and 12 weeks. Granuloma cells express Cx43, with considerable reduction in Cx43+/- mice. Moreover, granuloma cells from Cx43v+/- mice displayed reduced proliferation and increased collagen deposition at late phases of the disease. Despite these findings, no reduction of size or cellularity of the lesions was found in comparison to wild-type mice. We didn?t find differences in relation to blood count and splenic lymphocyte population CD4, CD8 and CD19. Peritoneal cells from animals of both genotypes presented similar production of NO and H2O2. However, blood neutrophils and monocytes from Cx43+/- mice, stimulated by PMA, displayed significantly increased oxidative burst. In conclusion, our results indicate that the deletion of one allele of the Cx43 gene clearly modifies the evolution of a granulomatous disease, supporting a role for this connexin on granuloma development.
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Hepatoma-derived growth factor regulation of the growth, the radiosensitivity and the chemosensitivity of human cancer cells. / 肝癌衍生生長因子(HDGF)對人類癌細胞的生長, 輻射敏感性及藥物敏感性之影響 / CUHK electronic theses & dissertations collection / Gan ai yan sheng sheng zhang yin zi (HDGF) dui ren lei ai xi bao de sheng zhang, fu she min gan xing ji yao wu min gan xing zhi ying xiangJanuary 2008 (has links)
Hepatoma-derived growth factor (HDGF) is commonly over-expressed in human cancer cells. It was able to stimulate cell growth. The expression level of HDGF was reported to correlate with poor prognosis of cancer therapy. It was found that HDGF is over-expressed in the fractionated gamma radiation conditioned HepG2 cells, which have higher growth rate, lower radiosensitivity and higher drug sensitivity. The aim of the present study was to investigate the role of HDGF in mediating these changes in human cancer cells and the underlying mechanisms. The results indicate that transfection of HDGF cDNA carrying vector stimulated the growth of cancer cells while knock-down of HDGF by transfection of HDGF antisense oligos not only suppressed the growth but also triggered apoptosis in human cancer cells. It suggests that HDGF stimulates cancer cell growth and acts as a survival factor for human cancer cells. Mechanistic study showed that knock-down of HDGF may trigger apoptosis through the regulation of the apoptotic pathways. The apoptosis induced by HDGF knock-down was mediated by the BAD regulated intrinsic apoptotic pathway and the Fas regulated extrinsic apoptotic pathway. The HDGF knock-down induced apoptosis was also mediated by the changes in the activity of the cell survival pathways, including the Ras/Raf/MEK/ERK, PI3K/Akt, NFkappaB and Jak/STAT pathways. In addition to the growth promoting function, HDGF was found to regulate the radiosensitivity and chemosensitivity of cancer cells. Overexpression of HDGF reduced the radiosensitivity and the level of apoptosis induced by gamma radiation. On the contrast, overexpression of HDGF increased the chemosensitivity and the level of apoptosis induced by anti-cancer drugs, including Taxol, doxorubicin (Dox) and tamoxifen. The results indicated that HDGF may stimulate the growth, reduce the radiation sensitivity and increase the drug sensitivity of cancer cells. HDGF may also be responsible for the changes in cancer cell properties after fractionated gamma radiation treatment. The present findings suggest that HDGF may be a potential target for cancer therapy. / Tsang, Tsun Yee. / Adviser: Tim Tak Kwok. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3497. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
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Avaliação do papel da conexina 43 no desenvolvimento do granuloma, experimentalmente induzido em camundongos / Evaluation of the role of connexin 43 in the development of granuloma, experimentally induced in miceSilvia Catarina Salgado Oloris 22 July 2005 (has links)
A doença granulomatosa inflamatória envolve interações coordenadas entre linfócitos, monócitos/macrófagos, células epitelióides, eosinófilos, neutrófilos e fibroblastos. A comunicação intercelular mediada por junções gap, constituídas por conexinas, é responsável pela homeostase tecidual. A Cx43 está presente em células linfóides, células mielóides, fibroblastos e outras. Assim, para compreendermos o possível envolvimento das conexinas no granuloma, nós analisamos o efeito da deleção heterozigótica de uma Gja1 (gene Cx43) na formação e desenvolvimento dos granulomas hepáticos, induzidos por ovos de Schistosoma mansoni. Para tanto, camundongos heterozigotos (Cx43+/-) e selvagens (Cx43+/+) foram infectados com cercárias de Schistosoma mansoni e avaliados nos tempos: 6, 8 e 12 semanas após a infecção. As células dos granulomas apresentaram expressão de conexina 43, notadamente após 12 semanas de infecção. As lesões dos camundongos Cx43+/- apresentaram índice de proliferação reduzido e aumento na deposição de colágeno em fases tardias da doença. Apesar desses achados, não se encontrou redução no tamanho e celularidade das lesões em comparação aos camundongos selvagens. Também não obtivemos diferenças em relação ao hemograma ou população de linfócitos esplênicos CD4, CD8 e CD19. As células peritoneais dos animais de ambos genótipos apresentaram produção de NO e H<SUB2O<SUB2 similares. Contudo, os neutrófilos e monócitos sanguíneos dos animais Cx43+/-, estimulados por PMA, apresentaram aumento significante do burst oxidativo. Concluindo, nossos resultados indicam que a deleção de um alelo do gene da Cx43 modifica claramente a evolução da doença granulomatosa, mostrando um papel desta conexina no desenvolvimento do granuloma. / Inflammatory granulomatous disease involves coordinated interactions among lymphocytes, monocytes/macrophages, epithelioid cells, eosinophils, neutrophils and fibroblasts. Intercellular communication mediated by gap junctions constituted of connexins, is responsible for tissue homeostasis. Cx43 is present in lymphoid cells, myelogenous cells, fibroblasts and others. In order to understand the possible involvement of connexins in granuloma, we analyzed the effect of the heterologous deletion of a Gja1 (Cx43 gene) on the formation and development of hepatic granulomas induced by Schistosoma mansoni eggs. Heterozigous (Cx43+/-) and wild-type (Cx43+/+) mice were infected with S. mansoni cercarie and evaluated after 6, 8 and 12 weeks. Granuloma cells express Cx43, with considerable reduction in Cx43+/- mice. Moreover, granuloma cells from Cx43v+/- mice displayed reduced proliferation and increased collagen deposition at late phases of the disease. Despite these findings, no reduction of size or cellularity of the lesions was found in comparison to wild-type mice. We didn?t find differences in relation to blood count and splenic lymphocyte population CD4, CD8 and CD19. Peritoneal cells from animals of both genotypes presented similar production of NO and H2O2. However, blood neutrophils and monocytes from Cx43+/- mice, stimulated by PMA, displayed significantly increased oxidative burst. In conclusion, our results indicate that the deletion of one allele of the Cx43 gene clearly modifies the evolution of a granulomatous disease, supporting a role for this connexin on granuloma development.
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Feedback-inhibition of glucagon-stimulated glycogenolysis in hepatocyte/kupffer cell cocultures by glucagon-elicited prostaglandin production in kupffer cellsHespeling, Ursula, Jungermann, Kurt, Püschel, Gerhard P. January 1995 (has links)
Prostaglandins, released from Kupffer cells, have been shown to mediate the increase in hepatic glycogenolysis by various stimuli such as zymosan, endotoxin, immune complexes, and anaphylotoxin C3a involving prostaglandin (PG) receptors coupled to phospholipase C via a G(0) protein. PGs also decreased glucagon-stimulated glycogenolysis in hepatocytes by a different signal chain involving PGE(2) receptors coupled to adenylate cyclase via a G(i) protein (EP(3) receptors). The source of the prostaglandins for this latter glucagon-antagonistic action is so far unknown. This study provides evidence that Kupffer cells may be one source: in Kupffer cells, maintained in primary culture for 72 hours, glucagon (0.1 to 10 nmol/ L) increased PGE(2), PGF(2 alpha), and PGD(2) synthesis rapidly and transiently. Maximal prostaglandin concentrations were reached after 5 minutes. Glucagon (1 nmol/L) elevated the cyclic adenosine monophosphate (cAMP) and inositol triphosphate (InsP(3)) levels in Kupffer cells about fivefold and twofold, respectively. The increase in glyco gen phosphorylase activity elicited by 1 nmol/L glucagon was about twice as large in monocultures of hepatocytes than in cocultures of hepatocytes and Kupffer cells with the same hepatocyte density. Treatment of cocultures with 500 mu mol/L acetylsalicylic acid (ASA) to irreversibly inhibit cyclooxygenase (PGH-synthase) 30 minutes before addition of glucagon abolished this difference. These data support the hypothesis that PGs produced by Kupffer cells in response to glucagon might participate in a feedback loop inhibiting glucagon-stimulated glycogenolysis in hepatocytes.
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Intercellular adhesion in resin canal tissue isolated from slash pine chlorite holocelluloseKibblewhite, R. Paul 01 January 1969 (has links)
No description available.
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