• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 18
  • 5
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 33
  • 12
  • 6
  • 6
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 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.
21

Viral Control of SR Protein Activity

Estmer Nilsson, Camilla January 2001 (has links)
<p>Viruses modulate biosynthetic machineries of the host cell for a rapid and efficient virus replication. One important way of modulating protein activity in eukaryotic cells is by reversible phosphorylation. In this thesis we have studied adenovirus and vaccinia virus, two DNA viruses with different replication stategies. Adenovirus replicates and assembles new virions in the nucleus, requiring the host cell transcription and splicing machinieries, whereas vaccinia virus replicates in the cytoplasm, only requiring the cellular translation machinery for its replication. </p><p>Adenovirus uses alternative RNA splicing to produce its proteins. We have shown that adenovirus takes over the cellular splicing machinery by modulating the activity of the essential cellular SR family of splicing factors. Vaccinia virus, that does not use RNA splicing, was shown to completely inactivate SR proteins as splicing regulatory factors. SR proteins are highly phosphorylated, a modification which is important for their activity as regulators of cellular pre-mRNA splicing. We have found that reversible phosphorylation of SR proteins is one mechanism to regulate alternative RNA splicing. We have demonstrated that adenovirus and vaccinia virus induce SR protein dephosphorylation, which inhibit their activity as splicing repressor and splicing activator proteins. We further showed that the adenovirus E4-ORF4 protein, which binds to the cellular protein phosphatase 2A, induced dephosphorylation of a specific SR protein, ASF/SF2, and that this mechanism was important for regulation of adenovirus alternative RNA splicing.</p><p>Inhibition of cellular pre-mRNA splicing results in a block in nuclear- to cytoplasmic transport of cellular mRNAs, ensuring free access of viral mRNAs to the translation machinery. We propose that SR protein dephosphorylation may be a general viral mechanism by which mammalian viruses take control over host cell gene expression.</p>
22

Functional Characterization of the Cellular Protein p32 : A Protein Regulating Adenovirus Transcription and Splicing Through Targeting of Phosphorylation

Öhrmalm, Christina January 2006 (has links)
<p>Cellular processes involved in the conversion of the genetic information from DNA into a protein are often regulated by reversible phosphorylation reactions. By modulating the phosphorylated status of key proteins their activity can either be enhanced or repressed. In this thesis I have studied the significance of phosphorylation in the regulation of transcription and splicing using human adenovirus as a model system.</p><p>The results show that the activity of the cellular SR family of splicing enhancer or repressor proteins are reduced in adenovirus infected nuclear extracts by a virus-induced hypophosphorylation. The viral E4-ORF4 was shown to induce SR protein dephosphorylation by recruiting the cellular protein phosphatase PP2A. The E4-ORF4/PP2A complex was shown to relieve the SR protein-mediated repression of late virus-specific splicing and further activate alternative splicing in transiently transfected cells. Collectively, these results showed that alternative splicing, like many other biological processes, is regulated by reversible protein phosphorylation.</p><p>Similarly, the cellular p32 protein was shown to cause hypophosphorylation of the SR protein ASF/SF2 resulting in a reduced RNA binding capacity of ASF/SF2. This change in ASF/SF2 RNA binding also had a drastic effect on the function of ASF/SF2 as a regulatory protein affecting splice site choice. The cellular p32 protein and the viral E4-ORF4 protein both target the same cellular splicing factor, ASF/SF2. However, they regulate splicing by different mechanisms. E4-ORF4 recruits a phosphatase to dephosphorylate ASF/SF2, while p32 sequester ASF/SF2 in an inactive complex.</p><p>Further, we demonstrated that overexpression of p32 during a lytic infection suppressed transcription from the adenovirus major late transcription unit. p32 induced a selective repression of CAAT-box containing promoters indicating the involvement of the transcription factor CBF/NF-Y in this regulation. A further analysis showed that p32 caused a hyperphosphorylation of the CTD of RNA Pol II, which resulted in a significant reduction in the processivity of Pol II during the elongation phase of transcription.</p><p>In summary, we have shown that E4-ORF4 regulates the activity of splicing regulatory SR proteins, and that p32 regulates the activity of the SR protein ASF/SF2 in splicing and Pol II processivity during transcription elongation. Mechanistically, both E4-ORF4 and p32 appears to function by regulating the phosphorylated status of key cellular proteins involved in these processes.</p>
23

Viral Control of SR Protein Activity

Estmer Nilsson, Camilla January 2001 (has links)
Viruses modulate biosynthetic machineries of the host cell for a rapid and efficient virus replication. One important way of modulating protein activity in eukaryotic cells is by reversible phosphorylation. In this thesis we have studied adenovirus and vaccinia virus, two DNA viruses with different replication stategies. Adenovirus replicates and assembles new virions in the nucleus, requiring the host cell transcription and splicing machinieries, whereas vaccinia virus replicates in the cytoplasm, only requiring the cellular translation machinery for its replication. Adenovirus uses alternative RNA splicing to produce its proteins. We have shown that adenovirus takes over the cellular splicing machinery by modulating the activity of the essential cellular SR family of splicing factors. Vaccinia virus, that does not use RNA splicing, was shown to completely inactivate SR proteins as splicing regulatory factors. SR proteins are highly phosphorylated, a modification which is important for their activity as regulators of cellular pre-mRNA splicing. We have found that reversible phosphorylation of SR proteins is one mechanism to regulate alternative RNA splicing. We have demonstrated that adenovirus and vaccinia virus induce SR protein dephosphorylation, which inhibit their activity as splicing repressor and splicing activator proteins. We further showed that the adenovirus E4-ORF4 protein, which binds to the cellular protein phosphatase 2A, induced dephosphorylation of a specific SR protein, ASF/SF2, and that this mechanism was important for regulation of adenovirus alternative RNA splicing. Inhibition of cellular pre-mRNA splicing results in a block in nuclear- to cytoplasmic transport of cellular mRNAs, ensuring free access of viral mRNAs to the translation machinery. We propose that SR protein dephosphorylation may be a general viral mechanism by which mammalian viruses take control over host cell gene expression.
24

Functional Characterization of the Cellular Protein p32 : A Protein Regulating Adenovirus Transcription and Splicing Through Targeting of Phosphorylation

Öhrmalm, Christina January 2006 (has links)
Cellular processes involved in the conversion of the genetic information from DNA into a protein are often regulated by reversible phosphorylation reactions. By modulating the phosphorylated status of key proteins their activity can either be enhanced or repressed. In this thesis I have studied the significance of phosphorylation in the regulation of transcription and splicing using human adenovirus as a model system. The results show that the activity of the cellular SR family of splicing enhancer or repressor proteins are reduced in adenovirus infected nuclear extracts by a virus-induced hypophosphorylation. The viral E4-ORF4 was shown to induce SR protein dephosphorylation by recruiting the cellular protein phosphatase PP2A. The E4-ORF4/PP2A complex was shown to relieve the SR protein-mediated repression of late virus-specific splicing and further activate alternative splicing in transiently transfected cells. Collectively, these results showed that alternative splicing, like many other biological processes, is regulated by reversible protein phosphorylation. Similarly, the cellular p32 protein was shown to cause hypophosphorylation of the SR protein ASF/SF2 resulting in a reduced RNA binding capacity of ASF/SF2. This change in ASF/SF2 RNA binding also had a drastic effect on the function of ASF/SF2 as a regulatory protein affecting splice site choice. The cellular p32 protein and the viral E4-ORF4 protein both target the same cellular splicing factor, ASF/SF2. However, they regulate splicing by different mechanisms. E4-ORF4 recruits a phosphatase to dephosphorylate ASF/SF2, while p32 sequester ASF/SF2 in an inactive complex. Further, we demonstrated that overexpression of p32 during a lytic infection suppressed transcription from the adenovirus major late transcription unit. p32 induced a selective repression of CAAT-box containing promoters indicating the involvement of the transcription factor CBF/NF-Y in this regulation. A further analysis showed that p32 caused a hyperphosphorylation of the CTD of RNA Pol II, which resulted in a significant reduction in the processivity of Pol II during the elongation phase of transcription. In summary, we have shown that E4-ORF4 regulates the activity of splicing regulatory SR proteins, and that p32 regulates the activity of the SR protein ASF/SF2 in splicing and Pol II processivity during transcription elongation. Mechanistically, both E4-ORF4 and p32 appears to function by regulating the phosphorylated status of key cellular proteins involved in these processes.
25

Investigating the Regulation and Roles of Histone Acetylase and Deacetylase Enzymes for Cellular Proliferation and the Adenovirus Life Cycle

Robinson, Autumn Rose 29 July 2020 (has links)
No description available.
26

Adenovirus Regulation of Host Cell Cycle and DNA Replication

Kafle, Chandra Mani 28 June 2022 (has links)
No description available.
27

Exploring the relationship between leadership, leadership behaviours and organisational culture

Egan, Julia January 2010 (has links)
This thesis explores the theme of leadership in the NHS, specifically focusing on nursing. Leadership has become an important area in recent years, particularly in relatiion to improving efficiency, effectiveness and quality of services. As nurses provide 80% of care in the NHS, their role is pivotal in achieving any change. Despite the importance placed on leadership in the NHS, literature shows little is known about perceptions of leadership, how leaders function or what importance staff place on the culture and context in which they work. This study is based on the findings of 28 qualitative interviews with leaders in two health boards in Scotland. Through the presentation of informants' perceptions, beliefs and collective accounts, the study illustrates how staff view leadership in the NHS and provides some significant results. Firstly, it proposes that leadership is comprised of two elements; one relating to individuals and one relating to how individuals function in organisations. Secondly, it indicates three models of leadership are particularly relevant and how these differ according to role and hierarchy. Thirdly, it reveals leadership and management as disticnct components. In nursing a number of complexities make these roles challenging, and the culture and context of health borads influence how these fundtion in practice. Finally, this research concludes that staff value a clear set of characteristics, styles and behaviours not related to vision and change but which centre on character, values, integrity and engagement. The study has considerable impolication for emerging work on leadership in the NHS and for the future development of leadership roles in nursing.
28

Protein processing strategies by adeno-associated virus type 5 (AAV5) and the effects of the adenovirus E4orf6/E1b-55k/Cullin 5 E3 ubiquitin ligase complex on AAV protein stability

Farris, Kerry David, Pintel, David J. January 2008 (has links)
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on March 10, 2010). Vita. Thesis advisor: David Pintel "August 2008" Includes bibliographical references
29

Adaptive Learning

Grundtman, Per January 2017 (has links)
The purpose of this project is to develop a novel proof-of-concept system in attempt to measure affective states during learning-tasks and investigate whether machine learning models trained with this data has the potential to enhance the learning experience for an individual. By considering biometric signals from a user during a learning session, the affective states anxiety, engagement and boredom will be classified using different signal transformation methods and finally using machine-learning models from the Weka Java API. Data is collected using an Empatica E4 Wristband which gathers skin- and heart related biometric data which is streamed to an Android application via Bluetooth for processing. Several machine-learning algorithms and features were evaluated for best performance.
30

ARIA-E vid behandling av Alzheimers sjukdom med monoklonala antikroppar / ARIA-E frekvens in treatment with monoclonal antibodies in patients with Alzheimers disease

Hall, Anna January 2023 (has links)
Introduction: Alzheimer's disease is a neurodegenerative disease that initially manifests itself primarily as impaired short-term memory and impaired language ability. The course of the disease is mainly due to an atrophy in the brain that can be attributed to the protein amyloid B and tau. Monoclonal antibodies that target Alzheimer's disease often have a high rate of cerebral edema, where proteinaceous fluid leaks into the extracellular space of the brain and creates edema. Some of the most common symptoms for amyloid-related imaging abnormalities (ARIA-E) are headache, dizziness, and blurred vision. In a few cases, patients with ARIA-E need to be hospitalized for observation, but most show a decline in ARIA-E within one to two months. Objective: To investigate the frequency of ARIA-E in clinical studies of monoclonal antibodies to patients with Alzhiemer's disease and to investigate the role of the ApoE4 allele in the development of ARIA-E. Method: Literature review of five RCT studies based on four different monoclonal antibodies. PubMed was used to search for the RCT-studies. Results: ARIA-E varies between different types of antibodies. ARIA-E usually occurs early in treatment when the degree of amyloid b is highest in the brain. Most cases are asymptomatic and treatment resumes within 1-2 months. Conclusion: Aria-E frequency correlates strongly with dose strength as well as APOE4 -status and most of the incidences are asymptomatic. With the right titration and individually selected drugs as well as individual dosages a safe care can be established for patients with Alzheimer's disease. If treatment is initiated at an early stage, the risk of side effects is reduced and more neurons can be saved from atrophy. The combination of several different types of medicine will further reduce the risk of ARIA-E.

Page generated in 0.0448 seconds