Дисертації з теми "Protein fibrillation"
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Vannoy, Charles Harvey. "Behavioral Effects of Functionalized CdSe/ZnS Quantum Dots in Self-Organization and Protein Fibrillation." Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/431.
Повний текст джерелаHöglund, Niklas. "Atrial fibrillation : treatment, associated conditions and quantification of symptoms." Doctoral thesis, Umeå universitet, Kardiologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-138378.
Повний текст джерелаOpel, A. "The role of regulators of G-protein signalling (RGS) in the predisposition to atrial fibrillation." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1394270/.
Повний текст джерелаSievers, Stuart Aaron. "Structural characterization of amyloid-like protein segments ann the rational design of peptide inhibitors of fibrillation." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1581476191&sid=1&Fmt=2&clientId=48051&RQT=309&VName=PQD.
Повний текст джерелаZhang, Yanhui, and 张雁惠. "Modulation of transient outward potassium channels by protein tyrosinekinases and demonstration of TRPC and TRPM channels in human atrialmyocytes." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47161644.
Повний текст джерелаpublished_or_final_version
Medicine
Doctoral
Doctor of Philosophy
Schirmer, Claire. "Chaperons moléculaires et tauopathies : effets de Hsp90 sur la fibrillation in vitro du peptide VQIVYK issu de la protéine tau." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S162/document.
Повний текст джерелаConformational diseases are characterized by protein misfolding which causes a loss of biological activity. Amyloidosis is one of these diseases, and it involves the ability of proteins to self-aggregate into specific structures called “amyloid fibers”. At least thirty human proteins, including tau, are known to form amyloid fibers. The tau protein is linked to several neurodegenerative diseases called tauopathies, including Alzheimer’s disease. Tau is in physiological conditions associated with microtubules and regulates their polymerization. In tauopathies, tau becomes hyper-phosphorylated and aggregates into neurotoxic neurofibrillary tangles (NFTs). Molecular chaperones, and particularly the 90-kDa heat shock protein (Hsp90), regulate tau homeostasis. The interaction between tau and Hsp90 involves several tau regions including the sequence VQIVYK. This short fragment is necessary and sufficient on its own to induce aggregation of the full tau protein in vivo. In vitro this hexapeptide is also able to form amyloid fibers similar to those found in vivo. We therefore used this hexapeptide as an in vitro model to study the process of amyloid fibrillation and to test Hsp90’s effects on it. We demonstrated that Hsp90 interacts specifically with peptide fibrillar structures and that Hsp90 is able to inhibit both the polymerization and depolymerization processes. This antagonistic role for Hsp90 allows the stabilization of intermediate amyloid species that may display a lower neurotoxicity. These results confirm that Hsp90 is involved in tau’s aggregation process and paves the way for new therapeutic perspectives in neurodegenerative diseases. Our study also provides clues to the understanding of how molecular chaperones assist in the folding of their client proteins
Lahtinen, J. (Jarmo). "Predictors of immediate outcome after coronary artery bypass surgery." Doctoral thesis, University of Oulu, 2007. http://urn.fi/urn:isbn:9789514286339.
Повний текст джерелаLIMA, Sandro Vagner de. "Investigação de sistemas e processos biológicos pela técnica de espectroscopia de impedância elétrica." Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/17146.
Повний текст джерелаMade available in DSpace on 2016-06-27T12:24:49Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese _Sandro Vagner de Lima.pdf: 6041788 bytes, checksum: 30432ac952cb4559dfe9e27b22cd9bf5 (MD5) Previous issue date: 2015-10-08
Esta tese de doutorado foi dedicada à investigação do modo como a técnica de espectroscopia de impedância elétrica (EIE) poderia ser usada para acompanhar os processos de mudanças conformacionais de macromoléculas biológicas, como proteínas e DNA. Para isso, usamos como sistemas modelos a proteína albumina do soro bovino (BSA), e a formação do complexo polianilina/DNA (PANI/DNA). Com a caracterização de soluções de DNA e BSA por EIE e sua modelagem elétrica convenientemente descrita pelo circuito de Randles (e sua variante), foram determinados os parâmetros relevantes para descrição dos fenômenos de desnaturação e de agregação da proteína e da precipitação do complexo PANI/DNA. As informações obtidas sobre a solubilidade desses últimos complexos são de grande utilidade para o entendimento dos mecanismos de interação entre cadeias de DNA e de polímeros condutores. Do mesmo ponto de vista da EIE, as sucessivas mudanças da conformação da proteína e os detalhes da cinética de sua agregação na interação com surfactantes foram adequadamente correlacionados com a característica elétrica do circuito de Randles das soluções correspondentes. Finalmente, estudos iniciais foram estendidos para a análise dos processos de fibrilação de proteínas. Para todos os problemas abordados, o uso da resistência de transferência de carga elétrica (RCT) (um parâmetro do circuito de Randles) nos permite sugerir ser a técnica de EIE apropriada para caracterizar as diferentes mudanças conformacionais envolvidas em fenômenos que resultam da interação de biomoléculas com moléculas de prova. Assim, ela se confirma como um método competitivo quando comparado ao uso da fluorescência e da absorção UV-Vis (técnicas rotineiramente adotadas para a análise desses problemas).
This doctoral thesis was devoted to the investigation of the technique of electrical impedance spectroscopy as an alternative method to assess conformational changes of biological macromolecules, such as proteins and DNA. For this, we used protein bovine serum albumin (BSA), and the formation of polyaniline (PANI)/DNA complexes as model systems. With the characterization of DNA and BSA solutions by Electrical Impedance Spectroscopy (EIS) and their electrical modeling conveniently described by the Randles circuit (and its variant), we determined the relevant characteristics of phenomena such as the denaturation and aggregation of proteins (BSA), and polymer/DNA complex formation (PANI/DNA). As a result of this approach we identified the existence of different interaction regimes between the chains of polyaniline and DNA molecules that are dependent on the concentration of PANI/DNA and the existence of equilibrium conditions which separate regions of precipitation/stability the PANI/DNA complex. Also from this point of view, the modes of interaction BSA / surfactants involved in the conformation changes well as typical stages associated with fibrillation kinetics were adequately correlated with the electric characteristic of the Randles circuit. In all studies carry out in this thesis, the analysis of the electric charge transfer resistance behavior (RCT) (a parameter of the Randles circuit) when confronted with the results obtained by standard techniques showed that the EIS presents reliable and some comparative advantages. These results allow us to provide an adequate and competitive alternative to conventional methods such as UV-Visible absorption, fluorescence and the use of probe molecules
Lindberg, Max. "Fluorescent fusion proteins as probes to characterize tau fibril polymorphism". Thesis, Linköpings universitet, Kemi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-158263.
Повний текст джерелаAndersson, Jonas. "Inflammation and lifestyle in cardiovascular medicine." Doctoral thesis, Umeå universitet, Medicin, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-36221.
Повний текст джерелаKhosravi, Zahra. "Nanoparticle-induced Changes in Insulin Fibrillation Behavior." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1597667499760057.
Повний текст джерелаLiuba, Ioan. "Focal atrial tachycardia : Insights concerning the arrhythmogenic substrate based on analysis of intracardiac electrograms and inflammatory markers." Doctoral thesis, Linköping : Department of Medical and Health Sciences, Linköping University, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-20461.
Повний текст джерелаBOUJELBENE, RIHAB. "Study of structure and fibrillation process of proteins using spectroscopy and nanotechnology." Doctoral thesis, Università degli studi di Brescia, 2022. http://hdl.handle.net/11379/560717.
Повний текст джерелаProteins play a vital role in all the processes taking place in a living organism. However, under pathological conditions, they may assemble as fibrils that are toxic and may cause a wide range of neurodegenerative disorders leading eventually to death. Studying proteins and fibrils can serve as a significant step toward new ways of diagnosis and therapy. This thesis proposes some spectroscopic techniques, mainly circular dichroism and plasmonic circular dichroism, to study proteins structures and to monitor fibril formation in vitro and in vivo. Chapter I is an introduction from literature of the two major subjects of this thesis: protein fibrils and spectroscopic techniques. The first part of this chapter delivers knowledge about the process, causes and toxicity of fibrillation taking Parkinson’s disease as an example of neurodegenerative disorder. The second part deals about chirality, circularly polarized light, circular dichroism and nanoparticles as they are the basics of the spectroscopic techniques used in this work. Chapter II is devoted to fibrils generated from alpha synuclein. This chapter illustrates how plasmonic circular dichroism was used to detect and differentiate between fibrils generated in vitro from full-length alpha synuclein and from a truncated form thereof. The technique was also applied to fibrils extracted and purified from different biological systems such as neuroblastoma cells and brain homogenates of mice and human patients. Chapter III explores two other protein systems: insulin, representing an easily available model for fibrils, and superoxide dismutase 1. Insulin fibrils with two opposite handedness were generated in vitro under denaturant conditions. These fibrils were then analyzed by fluorescence, circular dichroism, circularly polarized luminescence and plasmonic circular dichroism. Dyes such as thioflavin T, congo red and bis-ANS have been used. As a preliminary study for another system which may undergo fibrillation, superoxide dismutase 1 has been considered. In particular the native protein has been compared to the one produced in ambient with Cadmium excess. The two forms have been examined with far UV-CD spectroscopy at variable temperature to monitor changes and differences in the secondary structure.
BOUJELBENE, RIHAB. "Study of structure and fibrillation process of proteins using spectroscopy and nanotechnology." Doctoral thesis, Università degli studi di Brescia, 2022. http://hdl.handle.net/11379/560715.
Повний текст джерелаProteins play a vital role in all the processes taking place in a living organism. However, under pathological conditions, they may assemble as fibrils that are toxic and may cause a wide range of neurodegenerative disorders leading eventually to death. Studying proteins and fibrils can serve as a significant step toward new ways of diagnosis and therapy. This thesis proposes some spectroscopic techniques, mainly circular dichroism and plasmonic circular dichroism, to study proteins structures and to monitor fibril formation in vitro and in vivo. Chapter I is an introduction from literature of the two major subjects of this thesis: protein fibrils and spectroscopic techniques. The first part of this chapter delivers knowledge about the process, causes and toxicity of fibrillation taking Parkinson’s disease as an example of neurodegenerative disorder. The second part deals about chirality, circularly polarized light, circular dichroism and nanoparticles as they are the basics of the spectroscopic techniques used in this work. Chapter II is devoted to fibrils generated from alpha synuclein. This chapter illustrates how plasmonic circular dichroism was used to detect and differentiate between fibrils generated in vitro from full-length alpha synuclein and from a truncated form thereof. The technique was also applied to fibrils extracted and purified from different biological systems such as neuroblastoma cells and brain homogenates of mice and human patients. Chapter III explores two other protein systems: insulin, representing an easily available model for fibrils, and superoxide dismutase 1. Insulin fibrils with two opposite handedness were generated in vitro under denaturant conditions. These fibrils were then analyzed by fluorescence, circular dichroism, circularly polarized luminescence and plasmonic circular dichroism. Dyes such as thioflavin T, congo red and bis-ANS have been used. As a preliminary study for another system which may undergo fibrillation, superoxide dismutase 1 has been considered. In particular the native protein has been compared to the one produced in ambient with Cadmium excess. The two forms have been examined with far UV-CD spectroscopy at variable temperature to monitor changes and differences in the secondary structure.
BOUJELBENE, RIHAB. "Study of structure and fibrillation process of proteins using spectroscopy and nanotechnology." Doctoral thesis, Università degli studi di Brescia, 2022. http://hdl.handle.net/11379/560719.
Повний текст джерелаProteins play a vital role in all the processes taking place in a living organism. However, under pathological conditions, they may assemble as fibrils that are toxic and may cause a wide range of neurodegenerative disorders leading eventually to death. Studying proteins and fibrils can serve as a significant step toward new ways of diagnosis and therapy. This thesis proposes some spectroscopic techniques, mainly circular dichroism and plasmonic circular dichroism, to study proteins structures and to monitor fibril formation in vitro and in vivo. Chapter I is an introduction from literature of the two major subjects of this thesis: protein fibrils and spectroscopic techniques. The first part of this chapter delivers knowledge about the process, causes and toxicity of fibrillation taking Parkinson’s disease as an example of neurodegenerative disorder. The second part deals about chirality, circularly polarized light, circular dichroism and nanoparticles as they are the basics of the spectroscopic techniques used in this work. Chapter II is devoted to fibrils generated from alpha synuclein. This chapter illustrates how plasmonic circular dichroism was used to detect and differentiate between fibrils generated in vitro from full-length alpha synuclein and from a truncated form thereof. The technique was also applied to fibrils extracted and purified from different biological systems such as neuroblastoma cells and brain homogenates of mice and human patients. Chapter III explores two other protein systems: insulin, representing an easily available model for fibrils, and superoxide dismutase 1. Insulin fibrils with two opposite handedness were generated in vitro under denaturant conditions. These fibrils were then analyzed by fluorescence, circular dichroism, circularly polarized luminescence and plasmonic circular dichroism. Dyes such as thioflavin T, congo red and bis-ANS have been used. As a preliminary study for another system which may undergo fibrillation, superoxide dismutase 1 has been considered. In particular the native protein has been compared to the one produced in ambient with Cadmium excess. The two forms have been examined with far UV-CD spectroscopy at variable temperature to monitor changes and differences in the secondary structure.
Infante, Nídia Cristina Lopes Estrela. "The effect of sucrose on protein stability and fibrillation of prion and S6 protein." Master's thesis, 2011. http://hdl.handle.net/10400.1/5668.
Повний текст джерелаA agregação e fibrilhação de proteínas têm um grande impacto no sector industrial e na medicina. O misfolding e a agregação de proteínas estão na origem ou são uma consequência de várias doenças neurodegenerativas como as doenças de Alzheimer e Parkinson. Para se protegeram de várias condições adversas as células utilizam vários mecanismos entre os quais a acumulação de osmólitos. Os osmólitos conseguem, entre outras funções, actuar no interior das células ao nível da estabilização de proteínas. Estudos in vitro demonstram que este efeito estabilizador dos osmólitos é também verificado fora do meio celular. Neste trabalho foram estudadas duas proteínas, a proteína ribossomal S6 de Thermus thermophilus e a proteína priónica de rato. A existência de um N-terminal não estruturado na proteína priónica não afecta a sua estabilidade. O efeito do osmólito sacarose na fibrilhação e estabilização destas duas proteínas foi analisado por medidas de equilíbrio e cinéticas. Foi demonstrado que a sacarose é capaz de compactar a estrutura nativa da proteína ribossomal S6 de T. thermophilus em condições que promovem a sua fibrilhação. A sacarose também afecta as cinéticas de folding e unfolding da proteína S6, diminuindo a velocidade de unfolding e aumentando a velocidade de folding. O mecanismo de estabilização pela sacarose não é específico, pois o seu efeito verifica-se globalmente em toda a estrutura proteica, tal como demonstrado usando uma estratégia de engenharia de proteínas. A sacarose atrasa o processo de formação e alongamento de fibras da S6 e da proteína priónica de rato. Este atraso no processo de fibrilhação da S6 resulta do efeito de compactação da estrutura nativa referido em cima. Porém, os estudos de toxicidade celular demonstraram que as fibras formadas na presença da sacarose são mais tóxicas para células neuronais.
Wang, Hsiang-Yun, and 王薌筠. "Exploring the effects of L-arginine on protein aggregation and fibrillation." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/72139157343837971760.
Повний текст джерела國立臺灣大學
化學工程學研究所
99
L -arginine is a type of semi essential amino acid, and does not cause any harm on human being due to its biologically compatible property. While several lines of evidence has indicated that L arginine can effectively reduce protein aggregation, the precise interacting mechanism regarding the aggregation inhibition induced by L- arginine still remains elusive. The first part of this thesis is aimed at exploring the effects of L- arginine on the formation of amorphous aggregates using papain as the model protein system. Our data revealed that low concentration of guanidine hydrochloride (GdnHCl) could induce papain aggregation at acid condition (pH 2.0) with the highest level of aggregation observed at 0.7 M GdnHCl, which was taken as the aggregation condition used in our study. We found that, when a small amount of L- arginine (final concentration 0.02- 0.2M) were present in papain solution, the amount of papain aggregation was augmented. However L- arginine was observed to dose dependently attenuate the extent of papain aggregation upon futher increase of L- arginine (final concentration 0.3- 1.5M). Therefore, we postulate that, similar to GdnHCl, L- arginine not only perturbs the structure of papain but also has hydrophobic interactions with papain. In addition, in order to explore the ability of L- arginine to retain papain activity when its anti aggregation potency was observed, neutral pH and 65°C were used as the aggregation inductive condition. Our results demonstrated that, whereas 1M L-arginine was sufficient to decrease papain aggregation, only 10% of papain activity was retained. We hypothesize that papain active sites may exhibit higher conformational flexibility than the enzyme molecule as a whole, resulting in the finding that the loss of papain activity precedes noticeable conformational change of papain. As for the study of protein ordered aggregation, we used bovine serum albumin (BSA) as model protein. When incubating BSA at 65°C for hours, there was a considerable reduction in the α helical content accompanied by increases in β- sheet content in the BSA solution containing immature fibrils. We found that L- arginine dose dependently reduced the thioflavin T (ThT) fluorescence of BSA. However, as revealed by transmission electron microscopy (TEM), size exclusion chromatography (SEC), and dynamic light scattering (DLS) results, L-arginin did not prevent amyloid- like fibril formation by BSA. We concluded that L -arginine competed against ThT for binding sites on BSA amyloid -like fibrils, leading to biased results in ThT fluorescence measurements. Moreover, the use of ThT fluorescence assay to screen for potential inhibitors against amyloid fibrillation can give misleading results.
Cifelli, Carlo. "Characterizing the Role of Regulator of G-protein Signalling 4 as a Mediator of Sinoatrial Node and Atrial Cardiomyocyte Function." Thesis, 2010. http://hdl.handle.net/1807/26139.
Повний текст джерелаMAGGIORE, BEATRICE. "Structural and aggregation properties of bovine α1-acid glycoprotein, a member of the lipocalin superfamily". Doctoral thesis, 2017. http://hdl.handle.net/11566/245551.
Повний текст джерелаα1-Acidglycoprotein (AGP) is an important member of the acute phase response involved in drug binding and modulation of the immune system. AGP belongs to the lipocalin superfamily, a wide group of proteins sharing a strikingly conserved β-barrel fold that serves as a binding site for a large number of hydrophobic and neutral molecules. Several biological functions have been associated to AGP, both in vivo and in vitro. AGP is able to bind and transport a wide number of hydrophobic molecules. Potential therapeutic uses of AGP in the treatment of immune diseases have been envisioned, including, for instance, reduction of histamine levels. In the light of these observations, a detailed knowledge of the structure and stability of AGP appears essential. Fourier-Transform infrared (FT-IR) spectroscopy has been extensively used in the investigation of AGP due to its sensitivity towards fluctuations within protein structures. A survey of several environmental conditions, including pH and disulfide redox state, has shown that strongly acidic and reducing environments induce concomitant denaturation and aggregation of the polypeptide chain following increases in temperature. My doctoral research has been undertaken to characterize AGP aggregates obtained in the presence of the disulfide-specific reducing agents. The binding of Thioflavin T dye indicate that the aggregates possess a cross-β motif, suggesting that they are amyloid in nature. A molecular interpretation on the fibrillation kinetics of AGP was proposed. The experimental data do not show a nucleation-dependent polymerization mechanism otherwise they suggest a downhill polymerization mechanism as described for transthyretin and serum albumin. In this model, an aggregation-prone species self-assembles to form the amyloid fibrils. Further support to the downhill polymerization mechanism was provided by the seeding experiments and a more accurate kinetic analysis of fibril formation.
Al-u'datt, Doa'a. "LOX and LOX-Like Proteins as Potential Therapeutic Target for Atrial Fibrillation." Thèse, 2019. http://hdl.handle.net/1866/22593.
Повний текст джерелаPeng, Gary. "Gating mechanisms underlying deactivation slowing by atrial fibrillation mutations and small molecule activators of KCNQ1." Thesis, 2017. https://doi.org/10.7916/D8R49WF7.
Повний текст джерелаKočková, Radka. "Vliv positivně inotropních a antiarytmických farmak na kardiovaskulární systém." Doctoral thesis, 2015. http://www.nusl.cz/ntk/nusl-333581.
Повний текст джерела