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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.
71

Transvection in Drosophila melanogaster : zeste dependent transvection in loss-of-function lamin mutants

Pasanen, Anneli January 2008 (has links)
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72

Dendritic cell response after exposure to Salmonella enterica with different LPS structure.

Engstrand, Annika January 2009 (has links)
Lipopolysaccharide (LPS) is a structure of the gram-negative bacteria that protect from chemicals and works as a stabilization component for the membrane. Studies show that LPS also may have a function to avoid immune defense. In this project we investigate two Salmonella enterica variants with different LPS conformation. The wild-type Salmonella got an originally LPS structure and the mutant form had a defect one. The bacteria were transfected with a green fluorescent protein (GFP) to allow measuring of phagocytosis. Monocytes were isolated from human blood and were incubated for several days with cytokines to give dendritic cells. The cells were exposed to each type of Salmonella and incubated for different times. After labeling with phalloidin and studies with fluorescent microscopy, phagocytosis and F-actin were measured. The results show that it is a difference in phagocytosis and F-actin depending on LPS conformation. That means that LPS may have a decisive role for the pathogenicity of Salmonella.
73

Molecular mechanism of tetraspanin CD9 mediated cell motility

Kotha, Jayaprakash, January 2007 (has links) (PDF)
Thesis (Ph.D. )--University of Tennessee Health Science Center, 2007. / Title from title page screen (viewed on July 16, 2007). Research advisor: Lisa K. Jennings, Ph.D. Document formatted into pages (xiv, 150 p. : ill.). Vita. Abstract. Includes bibliographical references (p.130-150).
74

The Expression, Purification and Characterization of Ebola Virion Protein 24 and Karyopherin Alpha 5

Obaid, Marina January 2018 (has links)
Ebolavirus (EBOV) is a single stranded RNA virus that causes haemorrhagic fever in humans and other mammals. The EBOV encodes 7 proteins, NP, L, VP30, VP35, VP40, GP and VP24. VP24 is believed to be one of the EBOV proteins that causes the extreme virulence of the pathogen. The protein blocks the interaction between PY-STAT1 and KPNA, a protein that is involved in the import of PY-STAT1 into the nucleus. The nuclear import of PYSTAT1 is therefore blocked. This leads to the inhibition of IFN signalling. The purpose of this study was to express and purify VP24 and KPNA5. The proteins recombinantly expressed as a fusion tag in E. coli in lysogeny broth. Purification of VP24 was done using immobilized metal ion affinity chromatography, size exclusion chromatography and ion exchange chromatography. Characterization of the protein was analysed using circular dichroism. The results obtained from this study showed that VP24 could be purified in pH 10 buffers with little loss of protein due to aggregation and the protein was folded with an alphahelical structure. The expression and purification of KPNA5 was more complicated and further evaluation is left for future studies. The established protocol for expression and purification of VP24 and the initial work on KPNA5 will go a long way to aiding future studies on the system, thus the answer to the question regarding the extreme virulence of EBOV will be closer.
75

Mutations E688K and G569R within the NALP3 gene, associated with development of hereditary auto inflammatory disorders

Fetah, Alija January 2009 (has links)
Different mutations within the NALP3 gene are thought to be associated with development of several types of hereditary auto inflammatory disorders such as neonatal onset multisystem inflammatory disorder (NOMID) and muckle-wells syndrome (MWS). In this work two separate mutations E688K and G569R were supposed to be constructed by site-directed mutagenesis in the cloned wild type NALP3 genes and further expressed in bacterial and mammalian host cells for functional studies in protein -protein interaction models.
76

Immunohistochemical study of canine mammary gland tumours

Veerle, Flama January 2005 (has links)
This study was carried out to determine the phenotype of special dog mammary gland tumours that were grown in nude mice. 26 tumours were examined by the immunohistochemical ABC-Elite protocol. The tumour tissues were labelled with following anti-human antibodies: - AE1/AE3 (pankeratin antibody) labelled epithelial and myoepithelial cells - CD 31 labelled endothelial cells - desmin labelled cross-striated and smooth muscle cells - myosin labelled cross striated muscle cells - neurofilament (NF) labelled nerve cells - osteopontin labelled preosteoblasts, osteoblasts and osteocytes - p63 labelled nuclei of the myoepithelial cells - smooth muscle actin (SMA) labelled the cytoplasm of myoepithelial cells - type I collagen labelled the extracellular matrix in connective tissue and bone - type II collagen labelled the extracellular matrix in cartilage - vimentin labelled fibroblasts, fibrocytes, lipocytes, smooth muscle cells, endothelial cells, nerve cells, macrophages and myoepithelial cells The tumours were also submitted to a double immunolabelling study using p63 and SMA. The study could not give a final conclusion about the origin the tumours. There was still need for more research to answer that question. However, the immunohistochemical technique was analysed in detail, in order to obtain perfect labelings. Initially, all the antibodies were tested on normal dog tissue, to acquire the best working dilutions with the lowest background problems. In the tumours, good results were obtained with these dilutions for the antibodies p63, SMA, vimentin, desmin, NF, AE1/AE3 and CD 31. Except for type I collagen, type II collagen and osteopontin that gave too much unspecific labelling of the mouse connective tissue. Even, when using the Vector® M.O.M. blocking kit, the results were still very difficult to interpretate. The antigen retrieval methods were evaluated for all the antibodies. The antibodies p63, SMA, vimentin, desmin, AE1/AE3, myosin, neurofilament and CD 31 needed the antigen retrieval treatment. The antibodies type I collagen and type II collagen needed the treatment with the enzyme pepsin, while osteopontin did not need any pretreatment at all. The double immunolabelling with p63 and SMA gave excellent results. Different combinations were tried out with different substrates, namely Vector® Nova RED, Vector® DAB and Vector® SG. Vector® methyl green was used as counterstaining, but it interfered with the other substrates, and better results were obtained without this counterstaining.
77

Importance of microenvironment and antigen in the regulation of growth and survival of CLL cells

Bergh, Ann-Charlotte January 2016 (has links)
Chronic lymphocytic leukemia (CLL) cells rapidly die when put in culture implying that microenvironmental signals delivered by accessory cells confer CLL cells with a growth advantage. Recent findings show that CLL cells are antigen experienced and antigen binding play a critical role in the pathogenesis of the disease. The overall aim of this thesis was to study the influence of the microenvironment and antigen binding in CLL. In paper I, we studied the influence of the small redox-regulatory molecule thioredoxin (Trx) on CLL cell survival and proliferation. We found Trx to be highly expressed in CLL lymph nodes (LNs), secreted from stromal cells surrounding proliferating CLL cells in proliferation centers, indicating growth promoting properties. Secreted Trx was also shown to protect CLL cells from apoptosis. In paper II, oxidized LDL was added to subset #1 CLL cells. However, in contrast to our hypothesis, we could not observe activation and proliferation of CLL cells. Instead subset #1 CLL cells were unresponsive/anergic through the B cell receptor (BcR). This anergic state could however be overcome by “wash out” of bound antigen or addition of toll-like receptor 9 stimulation in some patients. Gene expression profiles differ between groups of CLL patients and in peripheral blood (PB) and LN compartment, due to different microenvironments. However, it is not known whether these differences also apply for DNA methylation. In paper III, we identified various genes that were alternatively methylated between IGHV mutated (M) and unmutated (UM) groups. For example prognostic genes, CLLU1 and LPL, genes involved in B cell signaling, IBTK, as well as numerous TGF-β and NF-κB/TNF pathway genes. The intensity and duration of BcR signals are fine-tuned by enhancing or inhibitory coreceptors. SHP-1 inhibits BcR-signals by dephosphorylation. In paper IV, we compared the expression and activity of SHP-1 in CLL cells from LN with matched PB samples. However, in contrast to our hypothesis, SHP-1 activity/phosphorylation status in PB and LN, did not differ significantly. This thesis, add another piece to the puzzle, on how the microenvironment and antigens influence CLL pathogenesis. Since great variations among individuals are seen, further studies in different groups of patients are necessary to elucidate the importance of antigen for the development of CLL.
78

The role of ion channels and intracellular metal ions in apoptosis of Xenopus oocytes

Englund, Ulrika January 2014 (has links)
Apoptosis is one type of programmed cell death, important during tissue development and to maintain the tissue homeostasis. Apoptosis comprises a complex network of internal signaling pathways, and an important part of this signaling network is the action of voltage‐gated ion channels. The aim of this thesis was to explore the role of ion channels and the role of intracellular metal ions during apoptosis in Xenopus laevis oocytes. The reasons for using these oocytes are that they are large, robust, easy to handle, and easy to study electrophysiologically. Apoptosis was induced either chemically by incubation of the oocytes in staurosporine (STS) or mechanically by centrifugation of the oocytes. Ion currents were measured by a two‐electrode voltage clamp technique, intracellular ion concentrations were measured either directly by in‐house developed K+‐selective microelectrodes or indirectly by the electrophysiological technique, and apoptosis was measured by caspase‐3 activation. Paper I describes that the intracellular K+ concentration was reduced by about 30 % during STS‐induced apoptosis. However, this reduction was prevented by excessive expression of exogenous ion channels. Despite the magnitude of the intracellular K+ concentration, either normal or reduced level, the oocytes displayed normal signs of apoptosis, suggesting that the intracellular K+ reduction was not required for the apoptotic process. Because the intracellular K+ concentration was not critical for apoptosis we searched for other ion fluxes by exploring the electrophysiological properties of X. laevis oocytes. Paper II, describes a non‐inactivating Na+ current activated at positive membrane voltages that was upregulated by a factor of five during STS‐induced apoptosis. By preventing influx of Na+, the apoptotic signaling network involving capsase‐3 was prevented. To molecularly identify this voltage‐gated Na channel, the X. tropicalis genome and conserved regions of the human SCNA genes were used as a map. Paper III, shows that the voltage‐gated Na channel corresponds to the SCN2A gene ortholog and that supression of this SCN2A ortholog using miRNA prevented cell death. In conclusion, this thesis work demonstrated that a voltage‐gated Na channel is critical for the apoptotic process in X. laevis oocytes by increasing the intracellular Na+ concentration.
79

Presence of desmin in human head and neck muscles : A pilot study

Bengtsson, Jenny, Kristensson, Olivia January 2020 (has links)
Background. Human head and neck muscles have a special morphology and fiber type composition, different from limb and trunk muscles. Recent studies show that human muscles in palate differ from limb by having a unique cytoarchitecture. A subgroup of muscle fibers lacked cytoskeletal protein desmin and C-terminus of dystrophin molecule. These proteins are considered ubiquitous in human muscles and their absence are only reported in genetic muscular disorders. Aim. In this study, we intend to explore if other head and neck muscles have muscle fibers with absence of the cytoskeletal protein desmin. Methods. Twenty-eight different head and neck muscle samples were acquired post-mortem from a female subject (34 years) and uvula and palatopharyngeus muscles were acquired from additional five subjects (two males, three females, mean age 54 years). For comparison, autopsies and biopsies from two limb muscles of healthy subjects were acquired. The muscles were analyzed for cytoskeletal intermediate filament protein desmin with immunohistochemical methods. Results. Our findings revealed that while all limb muscles showed immunoreaction for the antibodies directed against the protein desmin, a subpopulation of head and neck muscle fibers lacked or had a faint immunoreaction for desmin. The highest proportion of muscle fibers lacking desmin were observed in the laryngeal (22.6%) and infrahyoid (19.1%) muscle groups, while the lowest proportions were found among jaw muscles (mean 0.7%). Conclusions. The result shows that head and neck muscles in general have a unique cytoskeletal build-up compared to limb muscles highlighting a functional evolutionary adaptation of these muscles.
80

Effect of doxorubicin exposure in breast cancer on single-cell level by scRNA-seq analysis

Lladós Armengol, Núria January 2021 (has links)
Doxorubicin is a highly effective chemotherapeutic agent against a variety of cancers; however, the exact mechanisms responsible for the effects of doxorubicin on cancer are not widely understood and have not been studied on a single-cell level. Single-cell RNA sequencing analysis is a recent technology that enables the assessment of transcriptional similarities and differences within a population of cells. This thesis aims to study the effects of doxorubicin in breast cancer on a single-cell level and see if there are differently affected subpopulations of cells. A single-cell RNA sequencing pipeline was developed in R and used to analyse breast cancer single-cells treated with doxorubicin. Quality control, filtering, cell-clustering, differently expression gene analysis, pathways analysis and cell type identification were performed. The results identified seven different subpopulations that demonstrated a differential expression of genes and expression-level of pathways such as NEIL3-mediated resolution of induced interstrand crosslinks related with the effect of doxorubicin on cancer cells. The analysis also suggests that two subpopulations of cells could consist of specific cell types potentially treatment-resistant. These findings reinforce the relation of doxorubicin effect on cancer with some important genes and pathways, as well as reaffirming the heterogeneity of breast cancer. As a novel contribution, the results show that different subpopulations of cells could be affected differently by doxorubicin exposure, but future studies with more samples should be performed to see if the analysis leads to similar results

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