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Ho, Tsun-bond Horace, and 何存邦. "Generation of Na+-coupled dicarboxylate cotransporter (NaDC-1) deficient mice for the study of NaDC-1's role in caloric restrictionand renal ischemia/reperfusion injury." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B38575231.
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Ho, Tsun-bond Horace. "Generation of Na+-coupled dicarboxylate cotransporter (NaDC-1) deficient mice for the study of NaDC-1's role in caloric restriction and renal ischemia/reperfusion injury." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B38575231.
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Chiu, I.-Ting Kathy. "Recovery of symbol sampling time for North American digital cellular (NADC) system." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/35451.
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Kheirkhah, Abkenar Robabeh. "Självaggregering i blandningar av gallsalteroch fosfolipid undersöktes med statiskoch dynamisk ljusspridning vid 21 ̊ C och 37 ̊ C." Thesis, Uppsala universitet, Institutionen för farmaci, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-446392.
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Introduction: Phospholipids amphiphilic structure gives them special properties such as self-aggregation, emulsifying and wetting properties. Among the various structures resulting from the dissolution of phospholipids in water are the liposome, which acts as a drug carrier. They also act as surfactants for wetting by adsorbing on the crystal surface to increase the hydrophilicity of hydrophobic drugs. Surfactants, such as bile salts, have been shown to have a good ability to solubilize and dissolve non-polar lipids. By mixing with bile salts, phospholipids can easily dissolve and form mixed micelles. For the breakdown of fats in the gastrointestinal tract, mixed micelles formed from bile salts and phospholipid play an important role as well as in solubilizing water-insoluble drugs and other drug delivery applications. Aim: Theaim of this project is to study mixtures of the bile salts sodium deoxycholate (NaDC) and sodium cholate (NaC) with the anionic phospholipid DMPG and to determine the mole fraction (composition) in the aggregates at the transition from micelles to bicolts in bile salt / phospholipid mixtures. In addition, we want to determine the average size and structure of the colloidal particles formed in the solutions near the transition. The phospholipid DMPG has a charge and our results will be compared with previous corresponding studies where the zwitterionic phospholipid DMPC was investigated. Methods: The structure and size of micelles and bilayers formed will be determined by Dynamic Light Scattering (DLS) and Static Light Scattering (SLS) and Determination of refractive index increment of NaC and NaDC. Complementary techniques such as surface tension, small angle X-ray scattering (SAXS) and cryo-TEM may be used. Results and Discussion: This study was able to show that aggregates for systems with a molar ratio of 0.05 to 0.20 of both NaC and NaDC at 21 degrees (°C), have an approximate size range between 3 and 10 nm. At 21 ° C the concentration range studied for both NaC and NaDC shows that the particles are larger in size at lower concentrations. Also, increasing the molar ratio of both bile salts, NaC and NaDC in the samples leads to a reduction in the particle size of the system. At 37 °C the system shows a significant increase in the size of the particles for both the bile salts, NaC and NaDC in a size range between 10 and 400 nm. However, at 37 ° C and for both NaC and NaDC in molar ratios of 0.05 and 0.10, the particle size increases with increasing sample concentration but in molar ratios of 0.15 and 0.20, the particle size decreases with increasing sample concentration. At 21 ° C the light scattering experiments for the systems in NaDC and DMPC showed that the size of the micelles decreased with increasing concentrations while the increasing molar ratio led to increased size corresponding to mixed systems of bile salts and DMPG but not at 37 ° C. This difference may be mainly due to the fact that DMPG is an anionic phospholipid that has a charge and the altered conical shape of the bile salts as well as spontaneous curvature at a higher temperature. At 21 ° C the light scattering experiments for the systems in NaDC and DMPC showed that the size of the micelles decreased with increasing concentrations while the increasing molar ratio led to increased size corresponding to mixed systems of bile salts and DMPG but not at 37 ° C. This difference may be mainly due to the fact that DMPG is an anionic phospholipid that has a charge and the altered conical shape of the bile salts as well as spontaneous curvature at a higher temperature. Conclusion: At 37 °C for NaC and NaDC in molar ratios of 0.05 and 0.10 other cmc are obtained, indicating the presence of large structures in the system. Where these large worm-like or rod-like structures are formed by micelles. Accurate prediction of what structures may be present in the system requires more detailed and more appropriate research methods which in turn also need more time to achieve the result. Due to the project's time constraints, it became impossible to use these methods. This difference may be mainly due to the fact that DMPG is an anionic phospholipid that has a charge. The bile salts' end conformation form as well as spontaneous curvature at higher temperatures.
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Nachtigal, Philipp [Verfasser]. "Die Rolle des Lysins 114 für die Funktion des Natrium-abhängigen Dicarboxylat-Cotransporters (NaDC-3) in den Nieren der Winterflunder / Philipp Nachtigal." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2009. http://d-nb.info/1044995122/34.
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Berger, Felicitas. "NMN-Adenylyltransferase und NAD+-Kinase essentielle Enzyme der NAD(P)+-Synthese /." [S.l. : s.n.], 2003. http://www.diss.fu-berlin.de/2003/163/index.html.
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Khalily, Mohammad Aref. "Synthesis Of New Mediators For Electrochemical Nad/nadh Recycling." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12612961/index.pdf.
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The synthesis of enantiopure compounds can be achieved by using dehydrogenases as biocatalysts. For instance, reduction reactions of prochiral compounds (ketones, aldehydes and nitriles) into chiral compounds can be achieved by dehydrogenases. These dehydrogenases are cofactor dependent where cofactor is Nicotinamide Adenin Dinucleotite having some restrictions that confines usage of dehydrogenases in organic synthesis including instability of cofactor in water and high cost. Therefore, suitable recycling methods are required and developed which are enzymatic and electrochemical. We will use an electrochemical approach for the regeneration of reduced co-factors.
All active compoundsmediator, cofactor and enzyme, will be immobilized on the electrode surface of the constructed reactor surface. Therefore only educts and products will exist in the reactor medium. A gas diffusion electrode will be employed as a counter electrode
which delivers clear protons to the system. Mediator will carry electrons to the cofactor for cofactor regeneration. Then, enzyme will utilize the cofactor and change the substrates to the products in high stereoselectivity. Our aim in this project is the synthesis of mediators and suitable linkers for enzyme, cofactor and mediator immobilization. In the first part of the study, mediators were synthesized which are pentamethylcyclopentadienyl rhodium bipyridine complexes. In the second part of the study, a conductive monomer (SNS) and linker were synthesized for immobilization of the enzyme. In the last part of the study, the reaction of galactitol dehydrogenase with monomer (SNS) was achieved.
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Ilic, Stefan. "Utilizing NAD+/NADH Analogs for the Solar Fuel Forming Reductions." Bowling Green State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1499262103862098.
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Johnson, James 1964. "Sensitive Microtiter Assays for NAD, NADP and Protein Quantification in Human Lymphocytes." Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc501179/.
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Intracellular levels of NAD are of renewed interest in clinical and basic science research due to the new discovery of enzymes which utilize NAD as a substrate. Microtiter assays for the determination of NAD, NADP and protein were developed as modifications of previously published methods. The resulting assays are simple, cost effective and sensitive. An improved method of isolating lymphocytes was also developed. The resultant procedure requires one hour and removes greater than 99.9% of the platelets. Lymphocyte pools were stabilized with the addition of ADP-ribosyltransferase inhibitors and a modified extraction procedure. These studies have led to the development of a method for evaluation of NAD in human lymphocytes that is sensitive, selective and suitable for automation.
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Naylor, Claire. "X-ray crystallographic studies of glucose 6-phosphate dehydrogenase." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360467.
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Wu, Weihua. "Relaxing the cofactor specificity of formate dehydrogenase from NAD+ to NADP+." Ann Arbor, Mich. : ProQuest, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1451100.
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Thesis (M.S. in Chemistry)--S.M.U., 2007.Title from PDF title page (viewed Nov. 19, 2009). Source: Masters Abstracts International, Volume: 46-04, page: 2123. Adviser: Ling Hua. Includes bibliographical references.
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Crowley, Louis J. "Structure-function studies of conserved sequence motifs of cytochrome b5 reductase." [Tampa, Fla] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0001913.
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Farooqi, Mohammed Junaid. "METHODS FOR IN SITU PIEZOPHYSIOLOGICAL STUDIES: OPTICAL SECTIONING VIA STRUCTURED ILLUMINATION AND FLUORESCENCE BASED CHARACTERIZATION OF NADH CONFORMATION." Oxford, Ohio : Miami University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1249225952.
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Åström, Nina. "NADH/NAD⁺ analogues and cyclodextrins in enzyme mimicking systems an experimental and computational investigation /." Lund : Organic Chemistry 1, Lund University, 1995. http://catalog.hathitrust.org/api/volumes/oclc/39781586.html.
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Leman, Géraldine. "Régulation de la fonction mitochondriale par le rapport NADH/NAD+ : le rôle clef du complexe I." Thesis, Angers, 2014. http://www.theses.fr/2014ANGE0016/document.
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Le NAD+ apparaît comme un régulateur majeur du fonctionnement mitochondrial. En effet, ce cofacteur régule non seulement l’activité de nombreuses enzymes impliqués dans le métabolisme énergétique (enzymes de la β-oxydation des acides gras, du cycle de Krebs) mais joue également un rôle dans la production d’espèces réactives de l’oxygène (ROS). Le NAD+ est aussi le cofacteur des sirtuines, des enzymes déacétylases régulatrices notamment du métabolisme mitochondrial. De plus, la mitochondrie est l’organite au sein duquel la concentration en NAD+ est la plus élevée (jusqu’à 70% du NAD cellulaire). Le complexe I, qui possède une activité NADH déshydrogénase, pourrait être l’un des régulateurs majeurs du rapport NADH/NAD+ mitochondrial. L’objectif de ce travail de thèse a été d’étudier le rôle du rapport NADH/NAD+ mitochondrial dans le métabolisme énergétique et l’implication du complexe I dans les pathologies mitochondriales. Nous avons mis en évidence qu’une modulation du rapport NADH/NAD+ mitochondrial (augmentation par un activateur pharmacologique ou diminution consécutive à une mutation touchant une sous-unité du complexe I, modifie de manière drastique le métabolisme énergétique notamment en activant ou inhibant la protéine SIRT3, isoforme mitochondriale des sirtuines. Le complexe I semble jouer un rôle majeur dans cette modulation. Le resveratrol, ciblant le complexe I, ainsi que le NMN, un précurseur du NAD+, permettent de restaurer ce rapport et d’améliorer ainsi le métabolisme mitochondrial. Nos résultats suggèrent donc que le rapport NADH/NAD+ pourrait être une cible thérapeutique particulièrement intéressante dans les déficits du complexe INAD+ appears as a main regulator of the mitochondrial function. Indeed, this compound not only regulates the enzymatic activity of enzymes involved in energetic metabolism (fatty acid oxidation, tricarboxylic acid cycle) but is also involved in ROS production. NAD+ is also the cofactor of sirtuins, deacetylase enzymes, in particular regulating the mitochondrial function. Moreover, mitochondria sequester most of the cellular NAD+ (up to 70 %). The complex I, which possesses an NADH dehydrogenase activity, is thought to be the most important regualtor of the mitochondrial NADH/NAD+ ratio. The work presented here aimed at studying the role of the mitochondrial NADH/NAD+ ratio in mitochondrial metabolism and to test the involvement of the complex I in mitochondrial disorders. We show that a modulation of the mitochondrial NADH/NAD+ ratio (increase by a pharmacological agent or decrease in complex-I mutated fibroplasts) severely affects the mitochondrial energetic function especially by interacting with SIRT3 a mitochondrial sirtuin isoform. The NADH/NAD+ ratio is highly regulated by complex I activity. Resveratrol, which targets the complex I, as well as NMN, a NAD+ precursor, improves the mitochondrial NADH/NAD+ ratio and consequently increases the mitochondrial metabolism. Our results strongly suggest that the mitochondrial NADH/NAD+ ratio could be an interesting therapeutic target especially in complex I- deficient patients
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Ali, Irshad. "Electrochemical investigations of the interactive behavior of Nicotinamide Adenine Dinucleotide (NAD+/NADH) with electrode surfaces: towards direct electrochemical regeneration of enzymatically-active NADH." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117104.
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Nicotinamide adenine dinucleotide NAD(H) is a co-enzyme which participates in a large number of biochemical processes in which it acts as a hydrogen and electron carrier. Hence, NAD(H) is found in two redox forms: oxidized, NAD+, and reduced, 1,4-NADH. Despite its high potential industrial use, due to its very high cost (especially that of 1,4-NADH) and the need to be added in a biochemical reactor in stoichiometric quantities, its current use is very limited. Hence, there is a need to develop in-situ 1,4-NADH regeneration methods. Electrochemical methods are of particular interest because of their potentially low cost and easy product isolation. However, the major problem in the electrochemical regeneration of enzymatically-active 1,4-NADH is the formation of an enzymatically inactive dimer, NAD2. This PhD project focused on (i) the investigation of fundamental aspects of the interaction of NAD+ with a glassy carbon (GC) electrode surface, in terms of the NAD+ reduction kinetics and its adsorption, and on (ii) the development of electrodes for the direct (non-mediated) electrocatalytic regeneration of enzymatically active 1,4-NADH. Potentiodynamic polarization measurements showed that under the experimental conditions employed, the NAD+ reduction reaction is under diffusion control, is irreversible (requires overpotential of more than -550 mV), and is of pseudo-first order with respect to NAD+. The kinetics of reduction of NAD+ on GC at a formal potential of the NAD+/NADH couple (-0.885 V) was found to be rather slow, and only moderately temperature dependent.It was determined that NAD+ is adsorbed on a GC electrode surface. The kinetics of NAD+ adsorption was found to be surface-charge dependent. The adsorption process was described by the Langmuir isotherm. The corresponding apparent Gibbs free energy of adsorption evidenced that the adsorption process is highly spontaneous. The influence of electrode potential and electrode material on the purity of regenerated 1,4-NADH was then investigated. It was found that the regeneration of 1,4 NADH from NAD+ in a batch electrochemical reactor employing non-modified electrodes (GC, Carbon Nanofibers /CNFs/, Ti, Ni, Co and Cd) is feasible. The purity (recovery) of 1,4-NADH regenerated on these electrodes was found to be highly potential- and material-dependant. The origin of the material/potential dependency was related to the strength of the metal-hydrogen (M-Hads) bond, and thus to the potential dependence of the Hads electrode surface coverage and the kinetics of the subsequent NAD-radical protonation by Hads. Among the above outlined non-modified electrodes, only GC and CNF electrodes were capable of producing the highest 1,4-NADH purity (99-100%), but at very high cathodic potentials (–2.3 V).Therefore, to produce high-purity 1,4-NADH at lower cathodic potentials, a GC electrode surface was patterned with electrochemically-deposited platinum and nickel nano-particles (NPs). It was demonstrated that when the GC electrode was patterned with Pt NPs, a 100% pure 1,4-NADH product was achieved at –1.6 V, while the Ni nano patterned GC surface gave 100% pure 1,4-NADH already at –1.5 V. The high purity of 1,4-NADH formed on the two nano-patterned electrodes was prescribed to the formation of Pt-Hads and Ni-Hads at significantly lower potentials than on bare GC and CNFs surfaces. It was found that purity of 1,4-NADH regenerated on the nano-patterned electrodes was dependent on the electrode potential, nano-particles size, and their surface coverage. Considering the energy input, the cost of the electrode, and the percentage of recovery of 1,4-NADH (i.e. its purity), the GC-Ni electrode was suggested as the electrode of choice for 1,4-NADH regeneration among all investigated electrodes (GC, CNF, Ti, Co, Cd, Ni, GC-Pt and GC-Ni).Nicotinamide-adénine-dinucléotide NAD(H) est une coenzyme qui participe à un grand nombre de processus biochimiques dans lesquels elle agit comme une transporteuse d'électrons et d'atomes d'hydrogène. En dépit de sa forte utilisation potentielle dans l'industrie, son utilisation actuelle est très limitée à cause de son coût très élevé (en particulier celui du 1,4-NADH) et la nécessité d'être ajouté en quantités stœchiométriques dans les réacteurs biochimiques. Par conséquent, il est nécessaire de développer des méthodes de régénération in-situ du 1,4-NADH. Les méthodes électrochimiques sont d'un intérêt particulier en raison de leur coût potentiellement faible et l'isolement facile du produit. Cependant, le problème majeur dans la régénération électrochimique du 1,4-NADH est la formation d'un dimère enzymatiquement inactif, NAD2. Ce projet de doctorat est axé sur (i) l'étude des aspects fondamentaux de l'interaction du NAD+ avec la surface d'un électrode en carbone vitreux (GC), en termes de la cinétique de réduction et l'adsorption du NAD+ sur la surface du GC, et (ii) le développement d'électrodes pour la régénération électrocatalytique directe (non médiatisée) du composé 1,4-NADH, active enzymatiquement actif.Les mesures de polarisation potentiodynamique ont montré que dans les conditions expérimentales utilisées, la réaction de réduction du NAD+ est contrôlée par la diffusion. Cette irréversible (nécessite une surtension de plus de -550 mV) et est de pseudo premier ordre par rapport au NAD+. La cinétique de réduction du NAD+ sur GC, an potentiel formel du couple NAD +/NADH (-0.885 V), est lente, et modérément dépendante de la température. Le NAD+ est adsorbé sur la surface de l'électrode en GC. La cinétique d'adsorption du NAD+ s'est avérée dépendante de la charge surfacique. Le processus d'adsorption a été décrit par l'isotherme de Langmuir. L'énergie de Gibbs d'adsorption correspondante a montré que le processus d'adsorption est très spontané.L'influence du potentiel et du matériel de l'électrode sur la pureté du 1,4-NADH régénéré, a ensuite été étudiée. Il a été constaté que la régénération de 1,4-NADH à partir de NAD+, dans un réacteur électrochimique discontinu, employant des électrodes non modifiés est possible. La pureté (récupération) du 1,4-NADH régénéré sur ces électrodes a été jugée dépendante du potentiel et du matériel de l'électrode. L'origine de cette relationentre la nature elu nature ela matériel et le potentiel été liée à la force de liaison métal-hydrogène (M-Hads), et donc à la couverture du Hads sur la surface de l'électrode, que dépend du potentiel. Seuls les électrodes en GC et CNF ont été capables de produire la plus haute pureté du composé 1,4-NADH (99-100%), mais à des potentiels cathodiques le élevés (-2.3 V). Donc, pour produire 1,4-NADH de haute pureté à faibles potentiels cathodiques, la surface d'une électrode en GC a été modifiée par des nanoparticules (NPs) de platine et nickel, déposées par voie électrochimique. Il a été démontré que lorsque l'électrode en GC a été modifiées avec des NPs de Pt, le produit 1,4-NADH, avec une pureté de 100%, a été obtenu à -1.6 V, tandis que l'électrode en GC modifiée avec les NPs de Ni a produit 1,4-NADH avec une pureté de 100% déjà à -1.5 V. La haute pureté du 1,4-NADH formée sur les deux électrodes nano- modifiée a été prescrite à la formation des liaisons Pt-Hads et Ni-Hads à un potentiel nettement inférieur à celui sur une surface nue en GC. Il a été constaté que la pureté du 1,4-NADH régénérée sur les électrodes nano-modelées est dépendante du potentiel d'électrode, de la taille des nanoparticules et de leur couverture de la surfacique. Compte tenu de l'apport énergétique le coût de l'électrode, et le pourcentage de récupération du 1,4-NADH (i.e. sa pureté), l'électrode GC-Ni a été suggéré l'électrode de choix pour la régénération du 1,4-NADH parmi tous les électrodes étudiés (GC, CNF, Ti, Co, Cd, Ni, GC-Pt et GC-Ni).
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Olausson, Torbjörn. "Mitochondrial and Escherichia coli nicotinamide nucleotide transhydrogenases relationship between structure and function studied by protein engineering /." Göteborg : Dept. of Biochemistry and Biophysics, University of Göteborg and Chalmers University of Technology, 1995. http://catalog.hathitrust.org/api/volumes/oclc/39176823.html.
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Cid, Hidalgo Dixon Andrés. "Cambio de especificidad por dinucleótido del sensor fluorescente peredox mediante diseño racional." Tesis, Universidad de Chile, 2018. http://repositorio.uchile.cl/handle/2250/151357.
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Tesis presentada a la Universidad de Chile para optar al grado de Magíster en Bioquímica área de Especialización en Proteínas Recombinantes y Biotecnología y Memoria para optar al Título de BioquímicoLos dinucleótidos de adenina nicotinamida (NAD(P)(H)) cumplen un rol fundamental como cofactores enzimáticos, principalmente en reacciones de oxido-reducción. Sus concentraciones intracelulares determinan el estado fisiológico celular, en especial la razón NAD(P)H/NAD(P)+, por lo que es necesario tener métodos que permitan una cuantificación confiable de estas moléculas. Los métodos in vitro e in vivo comúnmente utilizados no permiten determinar el estado redox intracelular con precisión dadas las dificultades analíticas que poseen. El diseño de Sensores Fluorescentes Codificados Genéticamente (GEFS, por su sigla en inglés) ayuda a superar esas dificultades, ya que, estos biosensores permiten la cuantificación in vivo y en tiempo real de moléculas específicas, sin dañar las células estudiadas. Estos sensores se diseñan a partir de la fusión de una proteína fluorescente permutada circularmente con un dominio sensor proteico capaz de generar un cambio conformacional en respuesta a la unión de un ligando específico. Utilizando esta estrategia, muchos GEFS han sido diseñados para la cuantificación in vivo de dinucleótidos. Entre los sensores de dinucleótidos publicados a la fecha de inicio de esta tesis, el sensor Peredox era el único GEFS capaz de detectar la razón NADH/NAD+ intracelular. Peredox utiliza como dominio sensor al represor transcripcional sensible al estado redox T-Rex del organismo Thermus aquaticus. Aunque T-Rex es capaz de unir tanto NADH como NAD+, sólo la unión del dinucleótido reducido induce un cambio conformacional de una forma abierta a una cerrada. Este fenómeno permite a Peredox detectar la razón NADH/NAD+. Usando Peredox y la información estructural de T-Rex como punto de partida, el objetivo de esta tesis fue estudiar los determinantes estructurales de especificidad de dinucleótido con el fin de avanzar hacia la generación de un GEFS capaz de detectar la razón NADPH/NADP+, del cual no hay sensores diseñados a la fecha. Para esto se utilizaron estrategias de Diseño Racional mediante aproximaciones in silico e in vitro. Se determinó experimentalmente que el loop β4-β5 de T-Rex contiene determinantes estructurales de la especificidad por dinucleótido. Mediante análisis de Potenciales Estadísticos, comparación de motivos de especificidad basados en homología y simulaciones de Dinámica Molecular, se determinó los residuos clave en la especificidad por NAD(H) y las mutaciones necesarias para obtener una variante NADPH preferente. Se evaluó el efecto de estas mutaciones en la especificidad por NAD(P)H a través de ensayos in vitro de fluorescencia, obteniéndose un sensor preferente por NADPH. Sin embargo, el sensor no presentó un mecanismo de unión mutuamente excluyente a NADPH y NADP+, condición sine qua non para que un sensor de cuenta de la razón NADPH/NADP+
Nicotinamide adenine dinucleotides (NAD(P)(H)) play a fundamental role as enzymatic cofactors, mostly on oxidation-reduction reactions. The intracellular concentrations of these dinucleotides determine the cellular physiological state, especially the NAD(P)H/NAD(P)+ ratio, so it is necessary to have methods that allow a reliable quantification of these molecules. The in vitro and in vivo methods commonly used do not allow to determine the intracellular redox state with accuracy, given the analytical difficulties they show. The design of Genetically Encoded Fluorescent Sensors (GEFS) aids to overcome these difficulties, since they can perform real-time in vivo detection of specific molecules, without damaging the cells studied. These sensors are designed from the fusion of a circularly permuted fluorescent protein with a protein sensor domain capable of generating a conformational change in response to the binding of a specific ligand. Using this strategy, many GEFS have been designed for in vivo quantification of dinucleotides. Among the dinucleotide sensors published at the start date of this thesis, the sensor Peredox was the only GEFS capable of detecting intracellular NADH/NAD+ ratio. Peredox uses the redox-sensing transcriptional repressor T-Rex, from Thermus aquaticus, as a sensor domain. Although T-Rex is capable of binding both NADH and NAD+, only the binding of the reduced dinucleotide induces a conformational change from an open to a closed form. This phenomenon allows Peredox to detect the NADH/NAD+ ratio. Using Peredox and the structural information of T-Rex as a starting point, the goal of this thesis was the study of the structural determinants of dinucleotide specificity, with aim to achieve to a GEFS capable of detecting the NADPH/NADP+ ratio. There is no sensor designed for this parameter to date. To achieve this goal, we used Rational Design strategies, through in silico and in vivo aproximations. We determined experimentally that β4-β5 loop of T-Rex contains structural determinants of dinucleotide specificity. Through statistical potential analysis, homology-guided comparison of specificity motifs and Molecular Dynamics simulations, a triple mutant of T-Rex was proposed. The effect of these mutations on the specificity for NAD(P)H was evaluated through in vitro fluorescence assays, obtaining a Peredox variant with NADPH preference. However, the sensor did not show a mutually-exclusive binding fashion of NADPH and NADP+, a sine qua non condition for a sensor of the NADPH/NADP+ ratio
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Strain-Damerell, Claire Michelle. "Functional analysis of Rex, a sensor of the NADH/NAD+ redox poise in Streptomyces coelicolor." Thesis, University of Sussex, 2011. http://sro.sussex.ac.uk/id/eprint/6308/.
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Maintenance of the intracellular NADH/NAD+ redox poise is vital for energy generation in cells. Gram-positive bacteria, including the antibiotic-producing organism, Streptomyces coelicolor, have evolved a regulatory protein Rex that both senses this ratio and mediates an adaptive response to changes in it. Rex is a dimeric redox-sensitive transcriptional repressor. It is capable of binding to both NAD+ and NADH, although only NADH is an effector, causing dissociation of the protein from operator (ROP) sites. As NADH levels rise during oxygen limitation Rex dissociates from its target genes allowing expression, which helps to restore the NADH/NAD+ ratio. Microarray-based expression studies had suggested that Rex regulated only a small number of genes. In this work, however, ChIP-on-chip analyses revealed 38 genes that are potential regulon members. Analysis of the Rex binding sites in S. coelicolor revealed new insights into the mode of binding and show that Rex can bind with low affinity to incomplete half sites. This work also focused on characterising two key Rex targets, ndh and nuoA-N, that encode non-proton-translocating and proton translocating NADH dehydrogenases, respectively. Whereas nuoAN is not essential and was not expressed in liquid media, ndh was essential for growth. Depletion of NDH from growing cells led to the induction of Rex target genes confirming that ndh and Rex play key roles in maintaining redox homeostasis. Structure-based dissection of Rex, via a close homologue in Thermus aquaticus, identified a key interaction between the NADH- and DNAbinding domains of Rex. An R29-D203' salt-bridge, that traverses the NADH binding and DNA binding domains of Rex, appeared to stabilise the DNA-bound form of Rex, but is ‘broken' in the presence of NADH. In the NADH-bound form of Rex, D203 alternatively interacts with Y111, which in turn interacts with the nicotinamide ring of NADH. In order to assess the importance of individual subunits in the dimeric Rex, a single-chain derivative was constructed and the NADH binding and DNA binding domains individually disrupted.
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Holowiecki, Andrew. "Catalysis of Mitochondrial NADH→NAD+ Transhydrogenation in Adult Ascaris suum (Nematoda)." Bowling Green State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1256953439.
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Venter, Nicolaas. "Drought responses of selected C₄ photosynthetic NADP-Me and NAD-Me Panicoideae and Aristidoideae grasses." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1018549.
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Grass species within South Africa show a photosynthetic subtype and phylogenetic response to rainfall gradients, with Panicoideae species (NADP-Me and NAD-Me) inhabiting mesic environments, while Aristidoideae species (NADP-Me) inhabit more arid environments. It is predicted that climate change will alter rainfall patterns within southern Africa, which could have implications for grassland distributions and functional composition. Globally, and in South Africa, species distributions indicates that NAD-Me species have a preference for more arid environments, but this may be complicated by phylogeny as most NAD-Me species belong to the Chloridoideae subfamily. Additionally, differences in the metabolism and energetic requirements of different carboxylation types are expected to confer different ecological advantages, such as drought tolerance, but the role of these different pathways is not well understood. Based on natural distribution and photosynthetic subtype differences, it was hypothesised that Panicoideae NADP-Me species would be less drought tolerant than Panicoideae NAD-Me and Aristidoideae NADP-Me species and that subtypes and lineages would show different drought recovery rates. Furthermore, drought sensitivity would be of a metabolic and not a stomatal origin and plants that maintained favourable leaf water status would be more drought tolerant and recover faster. This was tested experimentally by comparing Panicoideae species (NADP-Me and NAD-Me) and NADP-Me species (Panicoideae and Aristidoideae). Plants were subjected to a progressive 58 day drought period and a recovery phase where gas exchange, chlorophyll fluorescence and leaf water relations were measured at select intervals. In conjunction with this, a rapid drought experiment was performed on Zea mays (NADP-Me: Panicoideae) plants where similar parameters were measured. Photosynthetic drought and recovery responses showed both a subtype and phylogenetic response. Panicoideae species were less drought tolerant than Aristidoideae species, although Panicoideae NAD-Me showed better recovery rates than Panicoideae NADP-Me species, while Aristidoideae species recovered the quickest. Panicoideae NAD-Me and Aristidoideae species maintained higher leaf water status during drought which contributed to the maintenance of PSII integrity and thus facilitated rapid photosynthetic recovery. During drought Panicoideae species showed greater metabolic limitations over Aristidoideae species and for the first time, lower metabolic limitations were associated with osmotic adjustment. This is a novel finding whereby osmotic adjustment and the subsequent maintenance of leaf water are key to preventing metabolic limitations of photosynthesis in C₄ grasses. Results from the Z. mays rapid drought study showed the limitations to photosynthesis were exclusively metabolic and unlikely to be a direct consequence of turgor loss. It was apparent that the response to drought was stronger amongst lineages, as NADP-Me species from different subfamilies showed a significant difference in drought tolerances. Aristidoideae species’ exceptional drought tolerance and predicted increased aridification could favour these species over Panicoideae species under future climates.
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Brekasis, Dimitris. "Identification and characterisation of Rex, a novel sensor of the NADH / NAD⺠redox poise in Streptomyces coelicolor." Thesis, University of Sussex, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418403.
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Al-Kassim, Loola S. Carleton University Dissertation Chemistry. "The NAD [superscript] + and NADP [superscript] + -linked activities of alcohol dehydrogenases: isolation, characterization and mechanistic study." Ottawa, 1989.
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Llanos, Ricardo Pariona. "Caracterização de interações proteína-DNA em tripanossomas." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/42/42135/tde-22092014-184950/.
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O T. cruzi, é o agente causador da doença de Chagas. O estado redox NAD+/NADH intracelular é fundamental na manutenção do metabolismo celular. A GAPDH apresenta a função de proteção do telômero em mamíferos contra degradação, isto por causa de ligar se ao telômero. Aqui, mostramos que a GAPDH recombinante de T. cruzi (rTcGAPDH) interage com o DNA telomérico. A rTcGAPDH liga ao DNA de simples fita. Mostramos que a GAPDH liga ao DNA telomérico in vivo em células epimastigotas, onde a [NADH] é maior que [NAD+], mas a adição de NAD+ exógeno bloqueia esta interação. Corroborando a hipótese de que o equilíbrio NAD+/NADH determina a interação GAPDH-telômero, vimos que o tripomastigota tem maior [NAD+] intracelular que a [NADH] e a GAPDH não é capaz de ligar se ao DNA telomérico. Além disso, o NADH exógeno resgata a interação GAPDH-telómero nesta fase. É importante o equilíbrio NAD+/NADH desta interação em tripanosomas, sugerindo que a proteção do telômero do parasita pode ser regulada pelo estado metabólico das células.The T. cruzi, is the causative agent of Chagas disease. The redox state of NAD+/NADH intracellular is critical in the maintenance of cellular metabolism. The GAPDH has the protection function of the telomere in mammals against degradation, because it is connecting to the telomere. Here we show the recombinant GAPDH of T. cruzi (rTcGAPDH) interacts with telomeric DNA. The rTcGAPDH binds to single-stranded DNA. We show GAPDH to bind to telomeric DNA in vivo epimastigotes cells, where [NADH] is greater than [NAD+], but the addition of exogenous NAD+ blocks this interaction. Corroborating the hypothesis that the NAD+/NADH balance determines the GAPDH-telomere interaction, we saw that the trypomastigote has higher [NAD+] that intracellular [NADH] and GAPDH is not able to connect to telomeric DNA. In addition, the exogenous NADH recovers the GAPDH-telomere interaction at this stage. It is important the NAD+/NADH balance this interaction in trypanosomes, suggesting that the protection of the telomere of the parasite can be regulated by the metabolic state of the cells.
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Liguori, Alessia <1985>. "Structural characterization of meningococcal vaccine antigen NadA and of its transcriptional regulator NadR in ligand-bound and free forms." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7552/.
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Serogroup B Neisseria meningitidis (MenB) is the cause of the invasive meningococcal disease (IMD). Bexsero is the first genome-derived vaccine against MenB. Neisserial adhesin A (NadA) is one of the three protein antigens included in Bexsero. The main aim of this work was to obtain detailed insights into the structure of vaccine NadA variant 3 (NadAv3) and into the molecular mechanisms governing its transcriptional regulation by NadR (Neisseria adhesin A Regulator). A deep understanding of nadA expression is important for understanding the contribution of NadA to vaccine-induced protection against meningococcal disease. NadA expression is regulated by the ligand-responsive transcriptional repressor NadR. The functional, biochemical and high-resolution structural characterization of NadR is presented in the first part of the thesis (Part One). These studies provide detailed insights into how small molecule ligands, such as hydroxyphenylacetate derivatives, found in relevant host niches, modulate the structure and activity of NadR, by ‘conformational selection’ of inactive forms. In the second part of the thesis (Part Two), strategies involving both protein engineering and crystal manipulation to increase the likelihood of solving the crystal structure of NadAv3 are described. The first approach was the rational design of new constructs of NadAv3, based on the recently solved crystal structure of a close sequence variant (NadAv5). Then, a comprehensive set of biochemical, biophysical and structural techniques were applied to investigate all the generated NadAv3 constructs. The well-characterized trimeric NadAv3 constructs represented a set of high quality reagents which were validated as probes for functional studies and as a platform for continued attempts for protein crystallization. Mutagenesis studies and screenings to identify a new crystal form of NadAv3 were performed to improve crystal quality; structure determination is ongoing. The atomic resolution structure of NadAv3 will help to understand its biological role as both an adhesin and a vaccine antigen.
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Xie, Wenjun. "Determination of NAD⁺ and NADH level in a single cell under H₂O₂ stress by capillary electrophoresis." [Ames, Iowa : Iowa State University], 2008.
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Li, Zhan-Hong. "Design of methyl mercaptan and ethanol biosensors and study on interactions of alcohol dehydrogenase with NAD+/NADH." Perpignan, 2014. http://www.theses.fr/2014PERP1251.
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Lee, Jae Yun. "Enzyme Properties and mRNA Expression of an NAD+ Scavenging System: NatV and NadV of Vibrio parahaemolyticus Phage KVP40." NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-07312008-124105/.
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KVP40 is a T4-like bacteriophage whose dsDNA genome (244,835 bp) has been sequenced (21). It infects Vibrio parahaemolyticus, which can cause disease in fish and shellfish, and gastroenteritis in humans when consumed in raw or under-cooked seafood (i.e., oysters). The KVP40 genome carries bacterial-like genes that have the potential to encode a pyridine nucleotide scavenging system for synthesis of NAD+. This is the first pyridine nucleotide salvage pathway predicted from a phage or eukaryotic viral genome (21). nadV and natV are the two genes that encode the hypothetical two-reaction NAD+ scavenging pathway. NadV, a nicotinamide phosphoribosyltransferase, catalyzes the first reaction that converts nicotinamide to nicotinamide mononucleotide (NMN). The NatV NMN adenylyltransferase activity yields NAD+. Nicotinamide adenine dinucleotide (NAD+) is an essential cofactor involved in fundamental processes in cell metabolism, and pathways for its synthesis are potential anti-microbial, therapeutic targets. The phage enzymes provide model targets for these studies. NatV, which catalyzes the second step of the pathway, also has a Nudix hydrolase domain in the C-terminal half. The purpose of this project was to characterize expression patterns of nadV and natV during KVP40 development in V. parahaemolyticus by using qRT-PCR; to characterize the enzymatic activity of NadV and NatV in a coupled-enzyme assay using alcohol dehydrogenase (ADH) to connect to fluorescent NADH; to identify possible substrates for the NatV Nudix hydrolase; and to use mass spectrometry to quantify product yields of the NatV reactions. qRT-PCR analysis showed that KVP40 nadV and natV were expressed early during infection relative to other phage genes used in this study. NadV-His6 and NatV-His6 enzymes were successfully purified by Ni2+ affinity HPLC and the levels of NADH produced were measured in a three step NadV-NatV-ADH reaction system. In the coupled assay, NatV-His6 converted NMN to 50 μmole of NAD+/sec/μg at 25°C. NatV NMNATase activity was also confirmed by mass spectrometry, in this assay, the rate was 350 μmole NAD+/sec/μg NatV-His6 at 25°C. NadV NAmPRTase activity was confirmed by producing 5.2, 4.9 and 5.0 μmole NMN/sec/μg NadV-His6 enzyme at 25, 30 and 37°C, respectively. Purified NadV used in the coupled enzyme also produced 2.7, 1.5, 1.3, 1.8 or 1.5 μmole NMN/sec/μg NadV-His6, when 10, 25, 40, 50 or 100 pmole NadV-His6 was respectively used in the reaction at 25°C. The âNudixâ activity of purified NatV was measured by a phosphate releasing assay and by mass spectrometry. Using the phosphate release Nudix hydrolase assay, ADP-ribose was identified as a preferred substrate for KVP40 NatV, followed by NAD+, NADH, and NADPH. In this assay, ADP-ribose as substrate yielded 0.6 μmole phosphate/sec/μg NatV-His6 at 37°C, when Mg2+ was supplied as the required metal ion. Mass spectrometry verified the NatV Nudix hydrolase preference for ADP-ribose as substrate, yielding the same rate of 0.6 μmole AMP/sec/μg NatV-His6 at 37°C in the presence of Mg2+. Together these data confirm the various enzymatic activities of key pyridine nucleotide scavenging enzymes encoded by phage KVP40. The time course of expression and in vivo activities suggest that pyridine nucleotide scavenging during KVP40 infection of V. parahaemolyticus is a functional and potential relevant pathway used by the phage.
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Shuler, Elizabeth. "The effects of flavonoids on mitochondrial membrane-associated reduced pyridine nucleotide-utilizing systems of adult Hymenolepis diminuta (cestoda) and Ascaris suum (nematoda)." Bowling Green State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1367950138.
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Vandock, Kurt P. "Mitochondrial Transhydrogenations in Manduca sexta: Relationship between Reversible NADPH → NAD+ Transhydrogenase and Ecdysone 20-Monooxygenase in Fifth Instar Larvae." Bowling Green State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1276033804.
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Amaro, Mariana. "De nihilo nihil = nada vem do nada." Master's thesis, Universidade da Beira Interior, 2010. http://hdl.handle.net/10400.6/1294.
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Este trabalho pretende contar a história de uma rapariga que veio estudar cinema para a Universidade da Beira Interior, onde tentou realizar um documentário, pretendendo pôr em prática tudo aquilo que tinha aprendido ao logo dos anos de Licenciatura e Mestrado em Cinema.
O documentário, teve como tema de base, o ponto de vista, o qual foi decidido por todos os alunos, numa reunião com o Director do Mestrado, seguido pela escolha de um orientador para o projecto. Assim, passei algum tempo a pensar no que ia desenvolver, até que me lembrei dos filmes que o meu pai tinha filmado ao longo da sua vida, e a partir dai desenvolver um documentário acerca da minha família.
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Tur, Jared. "Cardiovascular regulation by Kvβ1.1 subunit." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6596.
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Heterologous expression systems such as COS-7 cells have demonstrated the profound effects of KCNAB1-3 or Kvβ1-3 proteins on voltage gated potassium channels (Kv) channels. Indeed, in the presence of these β-subunits transiently expressed Kv channels are often modulated in multiple ways. Kv channel membrane expression is often increased in the presence of β-subunits. In addition, non-inactivating Kv currents suddenly become fast-inactivating and fast-inactivating channels become even faster. While much research has demonstrated the profound effects the β-subunits in particular the Kvβ1 subunit have on transiently expressed Kv currents little to date is known of the physiological role it may play. One study demonstrated that by “knocking out” Kvβ1 cardiomyocyte current changes were noted including a decrease in the Ito,f current. While this novel finding demonstrated a key cardiac physiological role of the Kvβ1 subunit it left many unanswered questions as to determine the cardiovascular regulation the Kvβ1 subunit provides. Indeed, cardiac arrhythmias and other electrical abnormalities within the heart such as long QT present patients with many unfortunate unknowns. Many of these incidences occur often abruptly with cardiac electrical abnormalities. Genetic research has begun to shine light on key cardiovascular genes in particular those coding for ion channels and auxiliary subunits or β-subunits. Kv channels and their β-subunits have gained particular notoriety in their key responsibility in restoring the resting membrane potential known as the repolarization phase. Indeed genetic manipulation and physiological examination of Kv channels and recently their β-subunits has demonstrated profound physiological results including prolonged QT durations within mice altered functional activity during physiological cycles such as estrus. While initial findings of Kvβ1 have demonstrated profound cellular and cardiomyocyte current alterations much still remains unknown. Therefore, this work hypothesizes that the Kvβ1 subunit provides a profound cardiovascular role in regulation and redox sensing at the physiological and pathophysiological level in both males and females. This work identifies a sex-based difference in cardiovascular regulation by Kvβ1 as well as demonstrated a profound redox sensing ability during altered metabolic states seen in pathophysiological conditions.
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Andy, Divya. "Approach for Identification of Binding Proteins of Calcium Mobilizing Second Messengers: NAADP and cADPR." University of Toledo Health Science Campus / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=mco1525202591650673.
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Baño, Paloma. "Nada que decir... O decir la nada, leyendo a Heidegger." Tesis, Universidad de Chile, 1999. http://repositorio.uchile.cl/handle/2250/110045.
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Informe de Seminario para optar al grado de Licenciado en FilosofíaLo que nos interesa destacar del “nada que decir” no es la expresión “que decir” (la cual podría perfectamente ser reemplazada por “que explicar”, “que escribir”, “que contar”, etc.), sino esa extraña palabra que habitualmente entendemos simplemente en el sentido de “no”. Cuando suponemos que para ser consecuentes con el “nada que decir” habría que dejar las páginas en blanco, estamos pensando el término “nada” en ese sentido que habitualmente solemos asignarle – el de la negación -, por lo cual el “nada que decir” se nos vuelve idéntico a “no decir”. No se trata aquí de rechazar de buenas a primeras ese sentido de la palabra “nada”; se trata más bien de llevar la expresión “nada que decir” a una situación en la cual se la vivencie realmente, en la cual cobre plena significación a causa de sentírsela como verdad. Es cierto que la frase funciona en muchos y muy diversos contextos: podemos replicar “nada que decir” frente a alguien que nos pregunte sobre un tema en particular, donde el tema puede ser cualquiera. Se trata de nada que decir ante alguien que nos pide explicaciones por alguna controvertida decisión nuestra, por ejemplo. En ese caso, puede que repliquemos “nada que decir” porque simplemente no queremos dar explicación alguna al respecto. Los ejemplos podrían ser muy variados, desde luego, pero siempre estarían referidos a un tema particular frente al cual uno decidiera callar, no decir.
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Hoydicz, Jennifer. "The narc files /." Full text available online, 2006. http://www.lib.rowan.edu/find/theses.
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Leiva, Reyes Jean, Yarur Marc Nicolet, Bravo Roberto Nieri, and Díaz Juan Pablo Rioseco. "Para nosotros nada." Tesis, Universidad de Chile, 2013. http://repositorio.uchile.cl/handle/2250/133281.
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Memoria para optar al título de PeriodistaEn primer lugar, este documental nació debido a un compromiso social latente en nosotros como periodistas y realizadores audiovisuales. Nos motiva denunciar los abusos cometidos en nuestro país, sobre todo hacia las personas más desposeídas. Vemos en Chile un Estado que limita su rol y despliega una legislación ambigua sin incluir a las minorías mayoritarias, con redes de influencia de operadores políticos, a lo que se suma una población desinformada y con muchas necesidades. Creemos que el documental cinematográfico es una poderosa herramienta de transformación de la realidad, si se desarrolla en la dirección correcta, esto es, apostando a través del cine por la conquista de una sociedad más justa, libre e igualitaria, mediante un trabajo artístico de calidad estética, y con un criterio ético y un lenguaje que pueda ser asimilado por miles de personas de distintos estratos y sectores sociales, tanto en Chile como en Latinoamérica y el mundo. Es por eso que escogimos el tema minero como eje de nuestro trabajo, ya que comprendemos que es una temática siempre actual y de tremenda relevancia, que necesita ser conocido por la sociedad en general. Es el cobre el mineral que más contribuye a la economía nacional y, al mismo tiempo, el que brinda mayores ganancias a capitales privados extranjeros. Este recurso natural adquiere un valor que está por sobre los derechos de los habitantes y el medio ambiente de aquellas zonas donde se obtiene, ya que los grandes proyectos de extracción, generalmente, conllevan el desalojo de pueblos y profundos cambios demográficos y ambientales en el territorio. Así ha sucedido por lo menos reiteradas veces en los últimos años, donde casos como el de la minera Los Pelambres o el de Pascua Lama en el norte chico, son solo los ejemplos más conocidos.
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Correia, Regiane Diniz [UNESP]. "Análise da assimetria da braçada do nado crawl através do nado atado." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/144340.
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Atualmente, a natação é praticada em diversos níveis, desde o terapêutico até o competitivo. Fatores biomecânicos que interferem no desenvolvimento da força propulsiva influenciam mais no desempenho do que na capacidade de produzir energia. Visando o alto rendimento, o objetivo deste trabalho foi detectar a assimetria da braçada do nado crawl através do nado atado e verificar a sua possível relação com a queda de desempenho. Com a utilização da dinamometria foi possível descrever as variáveis dinâmicas da força da braçada através de célula de carga, e com o auxílio da cinemetria comparar as variáveis da assimetria entre os braços e a frequência média de ciclos de braçadas. O método do nado atado foi empregado para avaliar 8 nadadores competitivos, com o mínimo de 2 anos de treinamento, de ambos os sexos, com idade entre 11 e 20 anos. Os dados de força obtidos foram coletados durante o nado crawl em um protocolo de 30 segundos, sendo 10 segundos iniciais de nado moderado, e 20 segundos de nado em intensidade máxima. As médias dos picos de força, frequência e ciclos foram descritas e comparadas entre as braçadas direita e esquerda. Os resultados da comparação entre a braçada direita e esquerda não diferiram estatisticamente: FM NA (80,28N ± 16,48); e FM NA (87,48 ±29,77) respectivamente. Quando comparados individualmente apenas, dois dos oito sujeitos apresentaram diferença entre as braçadas (p<0,05). Os resultados sugerem que os nadadores que apresentam assimetria significativa podem estar relacionado com o estilo do nado, técnica e treinamento específico. O índice de assimetria encontrado nos outros nadadores não é considerado fator crítico. Assim, o nado atado continua sendo uma das melhores formas de mensuração da força, e pode ser utilizado como prognóstico de treinamento, em provas de curta distância.
Currently, swimming is practiced at various levels, from the therapeutic to the competitive. Biomechanical factors that affect the development of the propulsive force, influence on performance more than the ability to produce energy. Aiming high performance , the aim of this study was to detect the asymmetry of the front crawl stroke by tethered swimming and check their possible relationship with the performance drop. With the use of grip strength was possible to describe the dynamic variables of the stroke force by load cell, and with the help of kinematics compare the variables of the asymmetry between the arms and the mean frequency of strokes cycles. The tethered swimming method was used to evaluate 8 competitive swimmers, with a minimum of two years of training, of both sexes, aged 11 and 20 years. The strength data were collected during the crawl in a 30-second protocol, 10 seconds of moderate swimming, and 20 seconds of swimming at maximum intensity. The average of the force peaks, frequency and cycles were described and compared between the right and left strokes. The results of the comparison between the right and left stroke were not statistically different: FM NA (80,28N ± 16.48); and FM NA (87.48 ± 29.77) respectively. When compared individually only two of the eight subjects showed difference between the lengths (p <0.05). The results suggest that the swimmers have significant asymmetry may be related to the style of swimming, technical and specific training. The asymmetry index found in other swimmers is not considered critical. Thus, the tethered swimming remains one of the best ways to measure the strength, and can be used as a prognostic training in evidence walking distance.
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Correia, Regiane Diniz. "Análise da assimetria da braçada do nado crawl através do nado atado /." Guaratinguetá, 2016. http://hdl.handle.net/11449/144340.
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Orientador: José Elias TomaziniCoorientador: Marcelo Sampaio Martins
Banca: José Geraldo Trani Brandão
Banca: Elaine Cristina Martinez Teodoro
Resumo: Atualmente, a natação é praticada em diversos níveis, desde o terapêutico até o competitivo. Fatores biomecânicos que interferem no desenvolvimento da força propulsiva influenciam mais no desempenho do que na capacidade de produzir energia. Visando o alto rendimento, o objetivo deste trabalho foi detectar a assimetria da braçada do nado crawl através do nado atado e verificar a sua possível relação com a queda de desempenho. Com a utilização da dinamometria foi possível descrever as variáveis dinâmicas da força da braçada através de célula de carga, e com o auxílio da cinemetria comparar as variáveis da assimetria entre os braços e a frequência média de ciclos de braçadas. O método do nado atado foi empregado para avaliar 8 nadadores competitivos, com o mínimo de 2 anos de treinamento, de ambos os sexos, com idade entre 11 e 20 anos. Os dados de força obtidos foram coletados durante o nado crawl em um protocolo de 30 segundos, sendo 10 segundos iniciais de nado moderado, e 20 segundos de nado em intensidade máxima. As médias dos picos de força, frequência e ciclos foram descritas e comparadas entre as braçadas direita e esquerda. Os resultados da comparação entre a braçada direita e esquerda não diferiram estatisticamente: FM NA (80,28N ± 16,48); e FM NA (87,48 ±29,77) respectivamente. Quando comparados individualmente apenas, dois dos oito sujeitos apresentaram diferença entre as braçadas (p<0,05). Os resultados sugerem que os nadadores que apresentam assimetria significativ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Currently, swimming is practiced at various levels, from the therapeutic to the competitive. Biomechanical factors that affect the development of the propulsive force, influence on performance more than the ability to produce energy. Aiming high performance, the aim of this study was to detect the asymmetry of the front crawl stroke by tethered swimming and check their possible relationship with the performance drop. With the use of grip strength was possible to describe the dynamic variables of the stroke force by load cell, and with the help of kinematics compare the variables of the asymmetry between the arms and the mean frequency of strokes cycles. The tethered swimming method was used to evaluate 8 competitive swimmers, with a minimum of two years of training, of both sexes, aged 11 and 20 years. The strength data were collected during the crawl in a 30-second protocol, 10 seconds of moderate swimming, and 20 seconds of swimming at maximum intensity. The average of the force peaks, frequency and cycles were described and compared between the right and left strokes. The results of the comparison between the right and left stroke were not statistically different: FM NA (80,28N ± 16.48); and FM NA (87.48 ± 29.77) respectively. When compared individually only two of the eight subjects showed difference between the lengths (p <0.05). The results suggest that the swimmers have significant asymmetry may be related to the style of swimming, technical and specific training. The asymmetry index found in other swimmers is not considered critical. Thus, the tethered swimming remains one of the best ways to measure the strength, and can be used as a prognostic training in evidence walking distance
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Michels, Solange. "Caractérisation des sites de fixation anionique de la glycéraldéhyde-3-phosphate déshydrogénase NAD-dépendante : relation avec la glycéradéhyde-3-phosphate déshydrogénase non phosphorylante NADP-dépendante." Nancy 1, 1995. http://www.theses.fr/1995NAN10380.
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La détermination de la structure tridimensionnelle de la glycéraldéhyde-3-phosphate déshydrogénase (GAPDH) phosphorylante NAD-dépendante en présence de sulfate d'ammonium avait permis de mettre en évidence deux sites de reconnaissance anionique auxquels on a attribué la fixation des groupements phosphates des deux substrats: le site Ps et le site Pi. Le premier volet de cette thèse consistait à caractériser ces deux sites de fixation anionique. Pour cela, les différents résidus participant à la composition de ces sites ont été mutés pour la GAPDH de Bacillus stearothermophilus. Les propriétés cinétiques de ces mutants ont été déterminées par des études de cinétique à l'état stationnaire et par des études de cinétique en mélange rapide et comparées à celles de l'enzyme de type sauvage. Nous présentons ici des arguments qui suggèrent que le groupement phosphate du glyceraldehyde-3-phosphate interagit avec le site Pi lors de l'étape précédant la formation de l'acylenzyme. L’étude de l'étape associée à la phosphorylation montre que cette étape devient limitante pour tous les mutants, contrairement à l'enzyme de type sauvage pour laquelle l'étape limitante est le relargage du NADH. D’autre part, nous montrons que l'étape associée à la phosphorylation est davantage perturbée pour des mutants du site Ps que pour les mutants du site Pi. Cependant, nos résultats ne permettent pas de définir, avec certitude, le site qui fixe le phosphate inorganique lors de l'étape de phosphorylation. Le deuxième volet de cette thèse consistait à définir l'origine ancestrale de la GAPDH non phosphorylante NADP-dépendante. La détermination de sa stéréospécificité de transfert d'hydrure, ainsi que la détermination de trois structures primaires suggèrent que cette enzyme et la GAPDH phosphorylante n'ont pas évolué à partir d'un ancêtre commun, mais qu'elle appartient probablement à la même famille de protéines que les aldéhydes déshydrogénases non phosphorylantes
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Barker, C. D. "Studies of NADH oxidation by NADH : ubiquinone oxidoreductase (complex I) from bovine mitochondria." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596366.
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The work described here focuses primarily on the flavoprotein (Fp) subcomplexes of complex I, as a subject for studying NADH oxidation. Fp is the smallest catalytically active subcomplex of complex I. It contains only two subunits and three cofactors – the FMN and a [4Fe-4S] cluster bound by the 51 kDa subunit, and a [2Fe-2S] cluster bound by the 24 kDa subunit. First, the development of a reproducible method for isolating stable and catalytically active Fp from complex I, using chaotropic resolution and ion-exchange chromatography, is described. The subcomplex produced contains the two subunits in equal amounts, and both [Fe-S] clusters and the FMN were present. Fp was capable of NADH oxidation and electron transfer to artificial electron acceptors in standard solution assays. The potential of the FMN was measured and values agree well with those reported from electron paramagnetic resonance (EPR). NADH oxidation was observed and explained by a model which incorporates mass transport of substrate. Michaelis-Menten enzyme kinetics, and interfacial electron transfer. The apparent potential of the active site under non-turnover conditions was higher than the values measured in the absence of substrate, providing insights into the mechanism of NADH oxidation. Unexpectedly, the rate of NAD+ reduction was fastest at intermediate potential – as the driving force for the reaction was increased a sharp maximum in activity was observed, after which there was a marked decrease. Two mechanistic models are proposed and shown to reproduce the experimentally observed voltammograms. In a second investigation, the [Fe-S] clusters in complex I were studied by EPR spectroscopy.
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Lanzerath, Carsten [Verfasser], Werner [Akademischer Betreuer] Hummel, and Vlada B. [Akademischer Betreuer] Urlacher. "Biokatalytische Synthese von α-Ketoglutarat und „Protein Engineering“ der NADH-Oxidase aus Lactobacillus brevis zur in situ-Cofaktorregenerierung von NADP+ / Carsten Lanzerath. Gutachter: Werner Hummel ; Vlada B. Urlacher." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2016. http://d-nb.info/108203391X/34.
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Wang, Zhijie. "Nouvelles stratégies de co-immobilisation de déhydrogénases, du co-factor NAD+, et de médiateurs redox, au sein de films sol-gel en vue d'applications en bioélectrocatalyse." Thesis, Nancy 1, 2011. http://www.theses.fr/2011NAN10061/document.
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Cette thèse décrit différentes stratégies pour co-immobiliser au sein d'un film sol-gel une déhydrogénase, le cofacteur NAD+/NADH et un système pour régénérer électrochimiquement ce cofacteur. L'immobilisation de la déshydrogénase dans la matrice sol-gel a été obtenue en utilisant un polyélectrolyte positivement chargé comme additif dans le sol de départ. Le film peut être déposé par les procédés d'évaporation ou d'électrogénération, permettant alors la fonctionnalisation d'électrodes d'or macroporeuses. La diaphorase a également pu être co-encapsulée pour la régénération du cofacteur NAD+. L'immobilisation du cofacteur a ensuite été obtenue par couplage chimique du NAD+ avec le groupement époxy du glycidoxypropylsilane avant formation du film. Plusieurs stratégies d'immobilisation du médiateur électrochimique ont alors été étudiées avec succès. Les espèces de type ferrocène ou des complexes d'osmium(III) peuvent être incorporées dans la matrice sol-gel par encapsulation de polymères portant ces médiateurs (Fc-PEI et polymère d'osmium) ou par co-condensation avec un ferrocène fonctionnalisé par un groupement silane. Finalement d'autres stratégies ont été étudiées basées sur la fonctionnalisation de nanotubes de carbone par un traitement micro-onde, par électropolymérisation du vert de méthylène, ou par recouvrement par un polymère de type acrylate portant des complexes d'osmium(III). L'électrogénération d'une couche mince sol-gel servant à immobiliser les protéines et le cofacteur à la surface des nanotubes fonctionnalisés par le polymère d'osmium(III) a alors permis d'observer une réponse électrocatalytique de stabilité remarquableIn this thesis, the research work was focused on designing functional layers based on silica sol-gel thin films to co-immobilize dehydrogenase, cofactor and electron mediator to get the most highly active systems. Immobilization of dehydrogenase in an active form in a sol-gel matrix was obtained by using a positively-charged polyelectrolyte as additive in the starting sol. The optimal sol can be deposited by evaporation or by electrodeposition and was successfully deposited in macroporous electrodes. The immobilization of the cofactor was investigated by simple entrapment, adsorption to carbon nanotube (CNTs), encapsulation of NAD+ chemically attached to dextran(NAD-dextran), and by in-situ coupling with glycidoxypropyltrimethoxysilane (GPS). The last approach allowed stable immobilization of the cofactor. Several mediators (Fc-PEI, Fc-Silane or Osmium polymer) were successfully co-immobilized with dehydrogenase and cofactor in the sol-gel matrix deposited by drop-coating. However, such co-immobilization did not operate in the electrogenerated sol-gel films. The strategies based on CNTs for mediator immobilization were finally developed. They include (1) micro-wave treatment (MWCNTs-µW), (2) electrochemical deposition of poly(methylene green) (MWCNTs-PMG), and (3) wrapping by osmium(III) polymer (MWCNTs-Os). MWCNTs-Os has been the only system that was successfully combined with sol-gel electrodeposition for co-immobilization of dehydrogenase and cofactor
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Didierjean, Claude. "Reconnaissance spécifique des cofacteurs NAD/NADP par les oxydoréductases : étude cristallographique du site de fixation du coenzyme dans la Glycéraldéhyde-3-phosphate déshydrogénase de Bacillus stearothermophilus." Nancy 1, 1997. http://docnum.univ-lorraine.fr/public/SCD_T_1997_0191_DIDIERJEAN.pdf.
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La glycéraldéhyde-3-phosphate déshydrogénase (GAPDH) est une enzyme essentielle des voies métaboliques et appartient à la famille des oxydoréductases NAD(P) dépendantes. L'une de ses particularités est d'utiliser le NAD ou le NADP en fonction de sa localisation subcellulaire : la GAPDH glycolytique reconnait très spécifiquement le NAD, tandis que la GAPDH chloroplastique présente une dualité de cofacteur avec une préférence pour le NADP. L'objectif de ce travail cristallographique était de caractériser le mode de fixation du NADP dans des mutants de la GAPDH glycolytique de Bacillus stearothermophilus. Plusieurs résidus du site de fixation du NAD de l'enzyme glycotique ont été substitués pour inverser sa spécificité vers NADP : - les résidus 33 a 35, 187 et 188 ont été mutés par les résidus correspondants dans les séquences des GAPDH chloroplastiques - l'acide aspartique 32 a été muté pour éliminer les répulsions électrostatiques avec le phosphate supplémentaire du NADP situé en position 2' du ribose de l'adénosine. Les structures du triple mutant D32G-S (D32G, L187A, P188S) et du quintuple mutant B-S (L33T, T34G, D35G, L187A, P188S) complexés avec NAD+ et NADP+ ont été résolues. Les limites de résolution obtenues sont comprises entre 2. 5 et 2. 2 A. Les résultats structuraux apparaissent en parfait accord avec ceux obtenus en enzymologie et par RMN : - la reconnaissance efficace du NADP+ par le mutant D32G-S est en partie due à l'élimination de la répulsion électrostatique intra sous-unité (D32G) et à l'élimination des contraintes stérique inter sous-unité (L187A, P188S). De plus, le 2'-phosphate est stabilisé par la chaine latérale du résidu S188 nouvellement introduit. En comparant avec les sites de fixation du NADP naturels connus, ce résultat montre que la présence d'un résidu chargé positivement n'est pas absolument nécessaire pour inverser la sélectivité de cofacteur de NAD vers NADP. - dans le mutant B-S, la faible affinité de l'enzyme de type sauvage pour NADP+ semble subsister essentiellement en raison de la répulsion électrostatique entre le 2'-phosphate et le carboxylate du résidu D32. Ainsi, le mutant B-S ne mime pas efficacement les GAPDH chloroplastiques, et les effets à longue distance et/ou de second ordre, difficiles à mettre en évidence, doivent être pris en compte pour obtenir un mutant de la GAPDH cytosolique se comportant comme la DGPDH chloroplastique.
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Silva, Fernando Maurício da. "Nada entre ser e tempo." Florianópolis, SC, 2005. http://repositorio.ufsc.br/handle/123456789/101778.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas. Programa de Pós-Graduação em Filosofia.Made available in DSpace on 2013-07-15T23:11:31Z (GMT). No. of bitstreams: 1 221474.pdf: 572655 bytes, checksum: 9007d49907fce3e5e4ba21754684d8c0 (MD5)
O que é, é no tempo e o tempo é algo que é: deste modo, ser e tempo são compreendidos a partir de uma relação metafísica prévia de identidade. Entretanto, quando a metafísica clássica teve que se perguntar pelo ser do tempo, não pôde se esquivar à questão pelo não-ser que compõe as suas partes. E o problema do não-ser transferiu-se para uma modalidade ôntica. Contudo, quando o próprio modo de indagar-se pelo ser e pelo tempo são postos em questão, desde a relação que o questionante - o ser-aí - tem com o questionado - o ser - em sua temporalidade, então a questão pelo ser do tempo não mais pode furtar-se ao problema do nada. Nada há além do tempo que lhe fundamente um ser - é este o problema que a questão do tempo não pode deixar de pensar quando se dirige ao seu ser. A pergunta de Heidegger pelo sentido do ser a partir do tempo não implica simplesmente em negar a filosofia clássica do tempo, tal como iniciada por Aristóteles, mas antes de tudo colocar a questão desde uma outra possibilidade: perguntar pelo tempo sem partir do sentido do ente, senão a partir do próprio sentido de ser, ao qual não pertence nada de ôntico.
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Possamai, Fernanda. "Teste do nado forçado repetido." reponame:Repositório Institucional da UFSC, 2013. https://repositorio.ufsc.br/handle/123456789/107269.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação Multicêntrico em Ciências Fisiológicas, Florianópolis, 2013.Made available in DSpace on 2013-12-05T23:39:57Z (GMT). No. of bitstreams: 1 318324.pdf: 11262181 bytes, checksum: 5a40328ce61f91e1b767c67ce984c616 (MD5) Previous issue date: 2013
O enriquecimento ambiental e o tratamento com fármacos antidepressivos são capazes de provocar efeitos comportamentais em ratos e camundongos expostos ao teste do nado forçado (TNF), bem como alterações na morfologia do sistema nervoso central. Objetivos: nosso objetivo foi avaliar os efeitos do tratamento crônico com imipramina, associado ao enriquecimento ambiental, sobre o comportamento no TNF-repetido e sobre a proliferação celular no giro denteado do hipocampo de ratos adultos. Metodologia: ratos machos Wistar (n=80) foram alojados por 40 dias, desde o 21° dia pós-natal, em ambiente padrão (AP) ou em ambiente enriquecido (AE). Após este período foram submetidos ao pré-teste (15min). No dia seguinte, os animais de cada ambiente foram subdivididos em quatro grupos e, 1 hora antes do Teste, receberam injeção intraperitoneal de: salina (SAL); imipramina (IMI 2,5 mg/kg ou 5mg/kg) ou fluoxetina (FLX 2,5 mg/kg). A partir do dia seguinte ao teste, foram administradas uma injeção diária destas substâncias nos animais dos respectivos grupos até o dia reteste 2. Teste e retestes foram filmados para posterior avaliação da latência, frequência e duração dos comportamentos. Após o reteste 2, os ratos foram sacrificados e foi realizada a imunoistoquímica para a detecção da proteína Ki-67 e doublecortina (DCX) no giro denteado (GD) do hipocampo. Resultados: O enriquecimento ambiental não afetou o comportamento durante o pré-teste, entretanto, ele foi capaz de reverter os efeitos da reexposição sobre a imobilidade. A dose de 5 mg/kg de imipramina e de 2,5 mg/kg de fluoxetina diminuiram o tempo e a frequencia da de imobilidade ("desespero comportamental") após 14 dias de tratamento dos animais alojados em ambiente padrão. Estes tratamentos não afetaram as contagens de Ki-67 e DCX no GD. Os efeitos da imipramina na dose de 5 mg/kg se potencializaram com o AE enquanto que a fluoxetina mostrou-se eficaz independente do tipo de alojamento. Estes tratamentos diminuíram as contagens de Ki-67 no GD. O tratamento com as duas doses de imipramina aumentaram as contagens de DCX no GD. Não houve nenhuma correlação entre as contagens de ki-67 ou de DCX com os comportamentos no TNF-repetido. Conclusão: Tanto o enriquecimento ambiental como a imipramina, em doses subefetivas no TNF, inibiram o desespero comportamental no TNF-repetido. Estes efeitos parecem não depender do aumento da neurogenese hipocampal,
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Ekbal, N. J. "NADH monitoring in shock states." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1463985/.
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Shock is defined as inadequate delivery or utilization of oxygen by the body tissues. Currently measured cardiorespiratory variables however, indicate decompensation only when patients become (near) shocked. Belated intervention often fails to reverse injury, leading to organ dysfunction and failure. Precise monitoring of the adequacy of tissue perfusion thus represents a major deficiency in clinical practice, particularly in the critically ill. As mitochondria utilize >90% of the oxygen consumed by the body, predominantly for ATP production, there is an obvious logic in targeting this organelle for monitoring the adequacy of tissue perfusion. Within mitochondria, NADH transfers electrons from the Krebs’ cycle to Complex I of the electron transport chain. In doing so, NADH is oxidized to NAD+. A rise in NADH:NAD+ ratio (redox state) will occur with a downstream block in the chain, e.g. due to lack of oxygen. As NADH (but not NAD+) fluoresces in response to UV light excitation (340nm), with an intensity relating to its concentration, and as most of the NADH signal represents changes in mitochondrial NADH, this property may be utilized for non-invasive assessment of tissue hypoperfusion. I validated the technique in vitro, and investigated its utility in rat shock models. During graded or abrupt decreases in the constituent parts of tissue oxygen delivery (cardiac output, haemoglobin and oxyhaemoglobin saturation), as well as during resuscitation, I assessed the relationship between skeletal muscle NADH fluorescence intensity, organ perfusion and oxygenation. I compared these against measures of global haemodynamics and tissue perfusion routinely measured in critically ill patients. With each graded insult, NADH fluorescence demonstrated increases reflecting severity of the insult, with improvements upon resuscitation. A persisting rise in NADH fluorescence >50% above baseline foretold death within the following 30-45 minutes, in advance of the other monitored variables. My results indicate that NADH fluorescence may be used for monitoring tissue hypoperfusion in shock states, and as a guide to the timing and adequacy of therapeutic interventions.
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Combret, Yves. "Contribution à l'étude du mécanisme du transfert énantiosélectif de l'hydrogène avec des modèles chiraux du NADH. Vers des modèles à énantiosélectivité élevée." Rouen, 1992. http://www.theses.fr/1992ROUES030.
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La thèse examine les paramètres qui influencent l'énantiosélectivité du transfert de l'hydrogène entre un réactif modèle du NADH portant un aminoalcool chiral en 3 et le phénylglyoxylate de méthyle. Il a été mis en évidence que la conformation du carbonyle en 3 de la structure 1,4-dihydropyridinique joue un rôle fondamental dans la réduction asymétrique d'un substrat prochiral. Des excès énantiomériques supérieurs à 90% ont été obtenus avec des modèles par ailleurs très réactifs. Divers aminoalcools chiraux ont été synthétisés ce qui permet de disposer d'une gamme élargie de réactifs modèles performants
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Rousset, Carine. "Etude structurale et fonctionnelle de la Quinolinate Synthase : une protéine fer-soufre cible d'agents antibactériens." Phd thesis, Université Joseph Fourier (Grenoble), 2009. http://tel.archives-ouvertes.fr/tel-00576109.
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La Quinolinate synthase (NadA) catalyse la condensation de l'iminoaspartate et de la dihydroxyacétone phosphate aboutissant à la formation d'acide quinolinique, un intermédiaire central dans la biosynthèse du nicotinamide adénine dinucléotide (NAD). Cette étude a permis de montrer que toutes les quinolinate synthases possèdent un centre [4Fe-4S] essentiel à l'activité et que seulement 3 résidus cystéines coordinent le centre métallique, les cystéines Cys113, Cys200 et Cys297 chez E. coli. Les propriétés spectroscopiques et biochimiques du centre [4Fe-4S] nous ont conduit à proposer que le centre fer-soufre joue un rôle de type aconitase/déshydratase dans la catalyse enzymatique. Deux autres cystéines impliquées dans la formation d'un pont disulfure, sont également essentielles à l'activité quinolinate synthase (Cys291 et Cys294 chez E. coli) en jouant probablement un rôle régulateur. Nous rapportons également une nouvelle hypothèse de mécanisme pour la formation de l'acide quinolinique, incluant l'isomérisation du glycéraldéhyde 3-phosphate en DHAP. Enfin, nous proposons NadA comme une cible potentielle d'agents antibactériens. Sur les différentes molécules testées in vitro, l'acide phosphoglycolohydroxamique (PGH) s'est avérée actif sur la quinolinate synthase d'E. coli et de M. tuberculosis, en agissant comme un inhibiteur compétitif du DHAP.
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Jorcke, Dierk. "NAD+-abhängige Signalwege in Mitochondrien ADP-Ribosyltransferase und NAD+-Glycohydrolase /." [S.l. : s.n.], 1998. http://www.diss.fu-berlin.de/1999/19/index.html.
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Allali, Naoual. "Covalent funtionalization of carbon nanomaterials for bioelectrochemical applications." Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0021/document.
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Les dispositifs bioélectrochimiques utilisent souvent le co-facteur NADH (nicotinamide adénine dinucléotide) comme biomolécule impliquée dans les réactions d’oxydo-réduction avec des enzymes de grand intérêt biochimique, comme par exemple les glucose oxydases ou les déshydrogénases. Il est nécessaire d’utiliser de nouveaux matériaux d’électrode afin de diminuer les sur-potentiels nécessaires au transfert d’électrons avec le système NADH/NAD+ et éviter l’adsorption des produits de la réaction à la surface de l’électrode (biofouling). Les nanotubes de carbone (NTCs) constituent un matériau conducteur de grande aire spécifique qui semble prometteur pour modifier ainsi la surface des électrodes. Ce travail de thèse a consisté à développer de nouvelles méthodes de greffage covalent de groupements fonctionnels électro-actifs vis-à-vis du système NADH/NAD+ en contrôlant les différentes étapes du procédé avec un protocole particulièrement poussé d’analyses physico-chimiques impliquant les spectroscopies de diffusion Raman, d’absorption infrarouge, de photo-électrons X, les microscopies électroniques à transmission, l’ellipsométrie spectroscopique et les analyses thermogravimétriques et de volumétrie d’adsorption. Nous avons développé un procédé reposant sur une première étape d’oxydation des NTCs par assistance micro-ondes dans des milieux acides dilués. Ceci permet de transformer les défauts existant à la paroi des nanotubes (atomes de carbone en hybridation sp3) pour les convertir en fonction acides carboxyliques, qui serviront dans les étapes ultérieures du procédé au greffage covalent des groupements électro-actifs. Ainsi l’intégrité structurale des NTCs, et donc leurs excellentes propriétés électroniques et mécaniques, sont préservées. Le succès de cette approche est pleinement démontré dans ce travail aussi bien en utilisant des nanotubes monoparois purifiés que des nanotubes multiparois. Un net effet électrocatalytique est obtenu avec les groupes fonctionnels dérivés du ferrocène. On montre également le rôle crucial de la nature du bras espaceur reliant les groupes électro-actifs à la paroi des NTCs. Ce travail a permis de mettre au point une méthode générale de greffage covalent des NTCs et son contrôle étape par étape. On montre enfin en perspective de ce travail qu’il est possible de greffer directement la molécule de NAD+ à la surface des NTCsBioelectrochemical devices often use the NADH co-factor (nicotinamide adenine dinucleotide) as a biomolecule involved in oxidation-reduction reactions with enzymes of high biochemical interest, such as glucose oxidases or dehydrogenases. It is necessary to use new electrode materials to reduce the over-potentials required for electron transfer with the NADH/NAD+ system and avoid adsorption of the reaction products to the electrode surface (biofouling). Carbon nanotubes (CNTs) are a conductive material with a large specific surface area that seems promising for modifying the surface of electrodes. This thesis work consisted in developing new methods for covalent grafting of electro-active functional groups with respect to the NADH/NAD+ system by controlling the various stages of the process with a particularly advanced physico-chemical analysis protocol involving Raman scattering spectroscopy, infrared absorption, X-ray photoelectron spectroscopy, transmission electron microscopy, spectroscopic ellipsometry and thermogravimetric and volumetric adsorption analyses. We have developed a process based on a first step of oxidation of the CNTs by microwave assistance in diluted acid media. This makes it possible to transform existing defects in the wall of the nanotubes (carbon atoms in sp3 hybridization) into carboxylic acid functions, which will be used in the subsequent steps of the process for covalent grafting of electro-active groups. Thus, the structural integrity of the CNTs, and therefore their excellent electronic and mechanical properties, are preserved. The success of this approach is fully demonstrated in this work both by using purified single-walled nanotubes and multi-walled nanotubes. A clear electrocatalytic effect is obtained with the functional groups derived from ferrocene. The crucial role of the nature of the spacer arm connecting the electro-active units to the wall of the CNTs is also shown. This work made it possible to develop a general method for covalent grafting of CNTs and its step-by-step control. Finally, we show in perspective of this work that it is possible to directly graft the NAD+ molecule onto the surface of the CNTs