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Stroebel, David. "Détermination structurale du complexe du cytochrome b6f par cristallographie aux rayons X." Paris 7, 2004. http://www.theses.fr/2004PA077228.
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Yassine, Wissam. "Etude structurale des protéines SNAREs dans le complexe protéine-lipide impliqué dans la fusion membranaire lors du processus d'exocytose." Bordeaux 1, 2008. http://www.theses.fr/2008BOR13767.
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La structure des protéines SNAREs (VAMP1 et Syntaxine1A) et de leur domaines trans- et juxtamembranaires (VAMP22, Syn23 et Syn27 respectivement) a été étudiée dans des membranes lipidiques modèles. Nous avons fait varier la concentration peptidique et la composition lipidique afin de déterminer les paramètres contrôlant l’activité de ces molécules dans la membrane durant la fusion. L’étude tructurale (IR et CD) des peptides VAMP22 et Syn23 ont montré une transition structurale dépendante de la concentration, entre un feuillet béta à forte concentration et une hélice alpha à faible concentration. Cette transition était réversible pour le peptide VAMP22 uniquement. Des perturbations de la membrane lipidique ont été observées suite à ce changement de structure. Les analyses structurales en PM-IRRAS de la protéine VAMP1 seule ou dans un film lipidique neutre (DMPC) a montré une transition structurale réversible entre une hélice alpha et un feuillet béta en fonction de la compression. Dans un film lipidique chargé du DMPG, cette transition n’a pas été observée. Cela laisse suggérer une influence des charges membranaires sur l’organisation de cette protéine. En parallèle, la protéine Syntaxine1A a montré une structure secondaire stable en hélice alpha, indépendamment de la composition lipidique de la membrane. L’addition de quatre résidus juxtamembranaires au peptide Syn23 était associée à une nouvelle organisation structurale du domaine transmembranaire. L’étude structurale associée à l’étude cinétique de fusion ou d’agrégation des peptido-liposomes du peptide Syn 27, permettent de suggérer un éventuel lien entre la structure et la fonction de ce peptide dans la membraneThe structure of SNARE proteins (VAMP1 & Syntaxine1A) and of their trans- and juxtamembrane domains (respectively VAMP22, Syn23 & Syn27) was investigated in synthetic lipid membranes. Different protein concentrations and lipid compositions were used in this study. VAMP22 and Syn23 peptides were studied in IR and CD. A structural transition between an alpha helix and a beta sheet was observed depending on peptide concentration. This transition was reversible only for VAMP22. Membrane Lipid phase was disturbed upon this structural evolution. PM-IRRAS data of pure full length VAMP1 protein film and mixed DMPC/VAMP1 film showed a dynamic behavior of this protein on the interface with a reversible structural transition upon surface compression/decompression cycles. Negatively charged lipid membranes (DMPG, DMPG/DMPC) prohibited this protein from changing structure under same conditions. Syntaxine1A protein subjected to a similar analysis showed no consequences of lipid composition or surface pressure on the structure of the originally alpha helix structured protein. Addition of four juxtamembrane residues to the Syn23 peptide produced modifications within the structural organization of this transmembrane peptide in model membranes. This larger peptide facilitated vesicles membranes fusion when organized as beta sheet
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Benslimane, Chouki. "Étude physiologique de Streptomyces ambofaciens producteur de la spiramycine en milieu complexe : effet de la source de carbone sur la consommation des acides aminés et des acylglycérols." Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL126N.
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L’amélioration rationnelle des procédés de fermentation passe par une meilleure compréhension de la physiologie des micro-organismes d'intérêt industriel. L’étude physiologique de Streptomyces ambofaciens producteur de la spiramycine, un macrolide à 16 membres, est largement étudiée en milieux synthétiques. L’utilisation de milieux très complexes, de type industriel et de composition souvent variable, limite ces études physiologiques dans ces conditions. Pour mieux comprendre le comportement cinétique de ce micro-organisme dans de tels milieux, nous avons abordé une étude du métabolisme initial des acides aminés, des lipides (acylglycérols) et de leur interactions dans des milieux complexes de type industriel contenant comme principaux substrats, des dextrines, de l'extrait de levure et de l'huile de maïs. Des études préliminaires en fioles d'erlenmeyer ont permis de maitriser les conditions permettant une reproductibilité des fermentations et une production de spiramycine satisfaisantes. Les interactions entre les principaux substrats du milieu de culture et leur incidence sur la production de spiramycine ont été étudiées. La présence de dextrines réduit les activités lipolytiques et protéolytiques, l'assimilation des acylglycérols, des acides gras libres à longues chaines, de certains acides aminés et la production de spiramycine. L’évolution des flux initiaux des différents substrats au cours des croissances est présentée. L’évolution de la constitution et de la mobilisation des réserves énergétiques (glycogène, tréhalose, lipides totaux et triacylglyérols) est analysée. Des hypothèses expliquant les relations entre composition en lipides de S. Ambofaciens, transport des acides aminés et production de spiramycine sont proposées
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Teixeira, da Silva Emerson Rodrigo. "Structure and dynamics of DNA confined in-between non-cationic lipid membranes." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14342/document.
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Une étude expérimentale sur la structure et la dynamique d'un complexe hydraté de fragments d'ADN (150 pb) et des phases lamellaires de lipides non-cationiques est présentée. Par la variation de d'hydratation, il est possible de contrôler le confinement imposé par cette matrice hôte sur les nucléotides insérés dans les couches aqueuses. L’organisation supramoléculaire du complexe est suivie par diffraction des rayons-X et des techniques de microscopie optique et électronique. Un riche polymorphisme de mésophases est observé en fonction du confinement. Dans le régime plus hydraté, les fragments se distribuent selon une orientation nématique. Dans la mesure où la quantité de l'eau diminue, le confinement des bicouches sur les nucléotides monte et des corrélations trans-membranaires donnent origine à des phases hautement organisées, avec de symétries rectangulaires et hexagonales (2D) d'ADN dans la phase lipidique. L'incorporation totale des nucléotides par la phase lamellaire est observée uniquement lorsque des grandes quantités d'ADN y sont présentes. Ce fait souligne une importance majeur des interactions de volume exclu. Une analyse du paramètre de Caillé montre que l'insertion des fragments diminue les fluctuations des membranes. À partir des ces observations, il est suggéré que la modification des interactions stériques entre des lamelles, associée à des effets interfaciaux ADN-membranes, est un mécanisme important dans le comportement de phases. Les propriétés dynamiques sont étudiés avec la technique de retour de fluorescence après photo-blanchiment (FRAP). Un modèle développé récemment pour l'analyse de diffusion anisotrope est testé avec succès, démontrant une corrélation proche entre structure et dynamiqueAn experimental study on the structural and dynamical properties of a hydrated DNA-non-cationic complex is presented. By varying the water amount, it is possible to control the confinement imposed by this host matrix over the organization of the nucleotides inserted within the water layers. The supramolecular assembly is investigated by X-rays diffraction and techniques involving both optical and electron microscopy. A rich polymorphism of mesophases is observed in function of confinement. In the more hydrated regime, the fragments are distributed according to nematic orientation in-between lamellae. As the water amount decreases, the confinement of bilayers over the particles increases and transmembrane correlations appear, giving raise to highly-ordered phases, with 2D-rectangular and -hexagonal symmetries of DNA embodied in the lamellar phase. The full incorporation of nucleotides by the lamellar phase is observed only in the presence of large amounts of DNA. This finding points to major importance of excluded volume interactions. An analysis of the Caillé parameter shows that the insertion of DNA reduces the fluctuations of membranes. From these observations, it is suggested that changes in the interactions between bilayers, together with the appearance of interfacial effects between DNA and membranes, are a mechanism relevant for the phase behavior of these systems. The dynamical properties of nucleotides are investigated through the fluorescence recovery after photobleach (FRAP). A model recently developed for analyses of anisotropic diffusion is sucessfully tested, demonstrating a close relationship between structure and dynamics
Um estudo experimental sobre aspectos estruturais e dinâmicos de um complexo hidratado de fragmentos de DNA (150 pb) e fases lamelares de lipídios não-catiônicos é apresentado. Variando-se a hidratação, é possível controlar o confinamento imposto por essa matriz hospedeira sobre os nucleotídeos inseridos na camada aquosa. O arranjo supramolecular do complexo é investigado por difração de raios X e técnicas de microscopia óptica e eletrônica. Um rico polimorfismo de mesofases é observado em função do confinamento. No regime mais hidratado, os fragmentos se distribuem segundo uma orientação nemática entre as membranas. À medida que a quantidade de água diminui, o confinamento das bicamadas sobre os nucleotídeos aumenta e correlações transmembranares aparecem, dando origem a fases altamente organizadas, com simetrias retangulares e hexagonais 2D de DNA entre as lamelas. A incorporação completa de nucleotídeos é observada apenas quando grandes quantidades de DNA estão presentes. Esse fato aponta para importância maior de interações de volume excluído. Uma análise do parâmetro de Caillé mostra que as flutuações das membranas diminuem com a inserção de DNA. A partir dessas observações, é sugerido que a alteração das interações entre membranas, aliada à aparição de efeitos interfaciais entre DNA e membranas, é um mecanismo relevante no comportamento de fase. As propriedades dinâmicas dos nucleotídeos são investigadas através da técnica de FRAP (fluorescence recovery after photobleaching). Um modelo recentemente desenvolvido para análise de difusão anisotrópica é testado com sucesso, demonstrando estreita correlação entre estrutura e dinâmica
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El, Fartah Habsaoui Souad. "Détection du traitement ionisant de denrées alimentaires : étude de la fraction volatile d'une matrice alimentaire riche en lipide : application d'autres techniques (RPE & TL) à la détection d'une matrice complexe." Aix-Marseille 3, 2001. http://www.theses.fr/2001AIX30013.
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Le traitement ionisant est un procédé qui permet d'assainir et d'augmenter la durée de conservation des aliments. Afin d'apporter la preuve que ce traitement a été appliqué ou non, il est nécessaire de disposer de méthodes simples de détection de l'ionisation. Notre travail de thèse a porté sur l'utilisation de trois méthodes : La chromatographie en phase gazeuse couplée à un espace de tête dynamique (CPG-DCI), la résonance paramagnétique électronique (RPE) et la thermoluminescence (TL). Dans un premier temps, nous avons étudié la fraction volatile de la matrice lipidique du jaune d'œuf en utilisant la CPG-DCI. Nous avons mis au point une technique fiable d'identification des nombreux pics chromatographiques ; nous avons ensuite étudié le mécanisme de radiolyse, puis comparé l'effet de l'ionisation sur deux matrices : - Lipides "purs " extraits du jaune d'œuf liquide, (matrice El) - Jaune d'œuf ionisé et dont les lipides ont été extraits après ionisation, (matrice 01) Les différences observées entre les deux matrices peuvent s'expliquer par l'absence de la vitamine E dans la matrice El. Nous avons donc étudié l'effet de la vitamine E sur les mécanismes de radiolyse des lipides du jaune d'œuf. .Irradiation is a treatment increasing hygienic quality and time storage of foodstuffs. It is necessary to have simple methods of detection to prove whether this treatment was applied or not. We used three methods: gas chromatography coupled with a dynamic head space (GC-DCI), electron spin resonance (ESR) and thermoluminescence (TL). At first, we studied the volatile fraction on egg lipid matrix by using the GC-DCI. We then studied the radiolysis mechanism of yolk egg, and compared the effect of ionisation of lipids before (01) and after (El) their extraction from egg. The observed differences between 01 and El were explained by the absence of vitamin E in the second matrix. We studied the effect of vitamin E on the radiolysis mechanism
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Papadopoulos, Dimitrios. "Synthèses d'analogues de lécithines : caractérisations physico-chimiques et biologiques." Nancy 1, 1996. http://www.theses.fr/1996NAN10323.
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La préparation des composés mimes de la structure des phosphatidylcholines (lécithines), en remplaçant les deux fonctions ester par des liaisons de type amide et une des chaînes grasses hydrogénées par une chaîne fluorée, est l'objectif de ce travail. Les amides, moins facilement hydrolysables que les esters, et les chaînes fluorées peuvent apporter des qualités originales et intéressantes pour une éventuelle utilisation dans divers domaines dont le domaine biomédical. La conception de ces mimes est basée sur le principe de la synthèse modulaire. L'acide 3-hydroxy-2-hydroxyméthyl-2-méthylpropionique est utilisé pour remplacer le glycérol dans son rôle de molécule pivot entre les chaînes hydrophobes et la tête polaire. Une première liaison amide s'effectue avec une amine grasse hydrogénée ou fluorée. L'activation sélective d'une des deux fonctions alcool restantes sur la molécule pivot permet sa substitution par le groupe azide (N3). La réduction de l'azide en amine primaire offre le substrat pour la formation d'une deuxième liaison amide, par couplage avec un acide gras hydrogéné ou fluoré. Les diamides, ainsi formés, hydrogénés ou mixtes sont des structures analogues des "céramides". L'addition du groupe "phosphocholine" sur les analogues céramides s'avère difficile, probablement à cause de la présence des groupes amides. Une autre stratégie de synthèse est adoptée et la phosphorylation se fait avant la réduction du groupe azide. Celui-ci apporte un renfort à la nucléophilie de l'alcool. Ainsi le 2- bromoéthyldichlorophosphate -précurseur du groupement phosphocholinique- se greffe sur les β-amido-γ-azido-alcools avec des rendements corrects. Après hydrolyse de la liaison P-Cl restante et le traitement du diester phosphorique bromé par la triméthylamine, les azido-Iysolécithines analogues ont été récupérées. La réduction de l'azide produit les amino-Iysolécithines. Sur ces dernières un acide gras, hydrogéné ou fluoré, est couplé. Des composés, hydrogénés et mixtes, mimes des lécithines sont ainsi préparés. L'étude physico-chimique des produits synthétisés montre que les azido- et les amino-lysolécithines ont des propriétés de surface analogues à celles des produits naturels. Par contre les composés mixtes ont un comportement, tant en activité de surface qu'en ce qui concerne l'apparition de phases en présence d'eau, relativement original. Ces composés se révèlent toxiques vis-à-vis des cellules malignes (U937). Leur toxicité se manifeste par apoptose, à des concentrations inférieures à 2 10-⁴ M, et par nécrose au delà de cette concentration. En outre, les produits fluorés présentent des taux d'apoptose plus importants que leurs analogues hydrogénés à concentration équivalente. Les résultats physico-chimiques et biologiques encouragent à poursuivre des études plus complètes à propos de ces molécules.
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Mekhalfi, Malika. "Production de lipides et étude de la régulation métabolique chez la diatomée Asterionella formosa." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4770.
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La diatomée d'eau douce A. formosa peut produire des lipides neutres en plus ou moins grandes quantités en fonction des conditions de culture. Ainsi, nous avons montré par exemple qu'une carence en silice stimule la production de triacylglycérols (TAGs) mais génère une diminution de la biomasse. En revanche, nous avons montré que l'addition de bicarbonate et de phytohormones augmente à la fois la biomasse et la production de TAGs. L'ajout de phytohormones dans les milieux de culture de cette diatomée résulte en une augmentation de l'activité d'enzymes dans les extraits et notamment celles du cycle de Benson-Calvin. Parmi ces enzymes, la GAPDH est une enzyme dont l'activité augmente significativement. Nous avons montré que chez A. formosa, cette enzyme forme un complexe ternaire avec la CP12 et la Férrédoxine NADP Réductase (FNR) et non pas avec la CP12 et la phosphoribulokinase comme chez la plupart des organismes photosynthétiques. La régulation de cette enzyme en est de fait modifiée. La phytohormone, 24-épibrassinolide conduit à une augmentation d'activité de la GAPDH qui résulte de la dissociation du complexe GAPDH-CP12 et la GAPDH n'est plus redox régulée. La GAPDH chez les diatomées est donc régulée par des interactions protéineprotéineA. formosa, a freshwater diatom, can produce different amounts of neutral lipids such as triacylglycerols (TAGs) under different growth conditions. We showed that as it is well-known for diatoms, starvation for silica increased the production of TAGs but decreased biomass. However, the addition of bicarbonate or phytohormones into the growth medium increased both biomass and TAGs. Addition of phytohormones increased the activities of enzymes in particular those of the Benson-Calvin cycle. Among the target enzymes of the Benson-Calvin cycle, GAPDH was strongly affected. We purified this enzyme and demonstrated that, in the diatom A. formosa, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from the Calvin cycle, forms a complex with the small chloroplast protein CP12 and Ferredoxin NADP Reductase (FNR), which is involved in the photochemical phase of photosynthesis. In cells treated with the phytohormone, 24-epibrassinolide, GAPDH was "free", not redox-regulated and not associated anymore with CP12. Therefore GAPDH from this diatom is regulated by protein-protein interaction but the GAPDH/CP12/FNR complex replaces the one formed between GAPDH, CP12 and phosphoribulokinase found in most photoautotrophs
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Punyamoonwongsa, Patchara. "Synthetic analogues of protein-lipid complexes." Thesis, Aston University, 2007. http://publications.aston.ac.uk/9803/.
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Hypercoiling poly(styrene-alt-maleic anhydride) (PSMA) is known to undergo conformational transition in response to environmental stimuli. The association of PSMA with lipid 2-dilauryl-sn-glycero-3-phosphocholine (DLPC) produces polymer-lipid complex analogues to lipoprotein assemblies found in lung surfactant. These complexes represent a new bio-mimetic delivery vehicle with applications in the cosmetic and pharmaceutical industries. The primary aim of this study was to develop a better understanding of PSMA-DLPC association by using physical and spectroscopic techniques. Ternary phase diagrams were constructed to examine the effects of various factors, such as molecular weight, pH and temperature on PSMA-DLPC association. 31P-NMR spectroscopy was used to investigate the polymorphic changes of DLPC upon associating with PSMA. The Langmuir Trough technique and surface tension measurement were used to explore the association behaviour of PSMA both at the interface and in the bulk of solution, as well as its interaction with DLPC membranes. The ultimate aim of this study was to investigate the potential use of PSMA-DLPC complexes to improve the bioavailability and therapeutic efficacy of a range of drugs. Typical compounds of ophthalmic interest range from new drugs such as Pirenzepine, which has attracted clinical interest for the control of myopia progression, to the well-established family of non-steroid anti-inflammatory drugs. These drugs have widely differing structures, sizes, solubility profiles and pH-sensitivities. In order to understand the ways in which these characteristics influence incorporation and release behaviour, the marker molecules Rhodamine B and Oil Red O were chosen. PSMA-DLPC complexes, incorporated with marker molecules and Pirenzepine, were encapsulated in hydrogels of the types used for soft contact lenses. Release studies were conducted to examine if this smart drug delivery system can retain such compounds and deliver them at a slow rate over a prolonged period of time.
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Mias-Lucquin, Dominique. "Dynamique et mécanique de complexes dystrophine-actine-lipides membranaires." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1B024/document.
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La dystrophine est une protéine filamenteuse qui contribue à la structuration des cellules musculaires en créant un lien entre le cytosquelette et le sarcolemme. Avec l’actine du cytosquelette et les lipides membranaires, la dystrophine représente l’un des éléments d’un complexe macromoléculaire, localisé sous la membrane plasmique, dont le rôle est la prévention des dommages qui pourraient être induits à force de contractions-relâchements répétés. De tels dommages, notamment des ruptures du sarcolemme, sont observés chez des personnes atteintes de myopathies de Duchenne (DMD) et de Becker (BMD), des maladies causées par des mutations qui altèrent l’expression ou la fonction de la dystrophine. Ces myopathies sont actuellement incurables et une connaissance approfondie de la relation structure-fonction de la dystrophine et de ses interactions avec ses partenaires s’avère absolument nécessaire à la mise au point de nouvelles stratégies de thérapies géniques. Cette protéine se compose de quatre domaines fonctionnels, dont un domaine central filamentaire, constitué de 24 répétitions successives d’un même motif structural, un faisceau de trois hélices alpha ou « coiled-coil ». Or, il a été récemment montré que la structure de ce domaine central n’est pas strictement linéaire et que certaines régions inter-répétitions (linker) forment des coudes, délimitant ainsi des sous-domaines d’interaction spécifiques. Cette thèse a pour objectif de comprendre l’origine de cette diversité de conformations inter-répétition dans un domaine structuralement homogène, et d’explorer comment elle permet à certaines régions de se différencier afin d’interagir avec l’actine et/ou les lipides membranairesDystrophin is a filamentous protein involved in muscular cells structure which links the cytoskeleton to the sarcolemma. Together with cytoskeletal actin and membrane lipids, dystrophin is a part of a macromolecular complex, located under the sarcolemma, which prevents damages induced during repeated muscle contractions and relaxations. Such damages, including sarcolemma disruption, are found in people with Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD), diseases caused by mutations altering dystrophin expression or function. There is currently no treatment to cure these myopathies, and a deep understanding of the structure-function of the dystrophin and its interactions with its partners is necessary to the development of gene therapy strategies. Structuraly, this protein is composed of four functionnal domains, including a long filamentous central domain, composed of 24 successive coiled-coil repeats. It was recently showed that the central domain is not rod shaped and some inter-repeats regions (linker) are kinked, delimiting specific interaction sub-domains. This thesis aims to bring knowledge about the basis of the conformationnal diversity of linkers in a structuraly homogenous domain in human dystrophin. We explore how dystrophin delimits some regions that interact with f-actin and/or membrane lipids
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Weissglas, Daphna. "Gene identification for complex cardiovascular lipid traits." Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1875374471&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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King, Katrice. "Phosphoinositide Phase Behavior in Complex Lipid Monolayer Systems." Digital WPI, 2016. https://digitalcommons.wpi.edu/etd-dissertations/129.
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Although phosphatidylinositol (PI) and phosphoinositides (PIPs) only comprise a small percentage of the inner leaflet of the plasma membrane, they mediate a large variety of signaling events. In previous studies, we have observed the absence of macroscopically discernible domains in mixtures of PI/PC and PI(4,5)P2/PC. The addition of cholesterol to these mixtures results in condensation of the monolayer and hence domain formation. To better mimic the ionic conditions and hydrogen bonding properties of the inner leaflet plasma membrane, we investigated in this study the effect of common inner leaflet plasma membrane lipids like phosphatidylethanolamine (PE), phosphatidylserine (PS) and PI, on phosphoinositide domain behavior in the presence of cholesterol and/or bivalent cations.
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Fazio, Sofia. "Rôle du complexe Ro60/RNYs dans les macrophages chargés des lipides." Electronic Thesis or Diss., Université Côte d'Azur, 2020. http://theses.univ-cotedazur.fr/2020COAZ6041.
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Ro60, protéine de liaison à l'ARN qui s'associe aux YRNAs pour former le complexe RoRNP, est une cible de la réponse immunitaire chez les patients atteints de lupus érythémateux disséminé (LED) et du syndrome de Sjögren (SS). Les autoanticorps anti-Ro60 dans le patients SLE et SS peuvent pénétrer à l'intérieur des cellules et se localiser dans le noyau. Les souris Ro60-/- développent un syndrome auto-immun et un statut pro-inflammatoire avec des caractéristiques de LED, indiquant l’implication de Ro60 dans la pathogenèse de cette maladie. D’autre part, les patients atteints de LED et de SS meurent principalement de troubles cardiovasculaires inflammatoires causés par une athérosclérose accélérée. Sur la base de ces observations, nous avons émis l'hypothèse que l'inflammation et les accidents cardiovasculaires chez les patients SLE/SS seraient causés par le dysfonctionnement du complexe Ro60 dans le noyau. Pendant ma thèse, nous avons montré que dans les macrophages chargés de lipides et dans les cellules THP-1 stimulées par des stimuli pro-inflammatoires, la dégradation des YRNAs permettrait à Ro60 de se lier à la chromatine, d’une façon indépendante de l'ARN. Par analyse des données de ChIP-seq, nous avons caractérisé la distribution des sites de liaison Ro60 sur la chromatine et trouvé une augmentation significative de la liaison de Ro60 lors du traitement à l'acide palmitique (PA) sur des promoteurs de gènes codants, indiquant que Ro60 pourrait être directement impliqué dans leur transcription. Ensuite, nous avons effectué une analyse Exon-Intron Split (EISA), approche bioinformatique permettant de quantifier les régulations transcriptionnelles et post-transcriptionnelles à partir de données d’ARN-seq de différentes conditions expérimentales grâce à des expériences en cinétique. L'analyse EISA a été appliquée aux données d’ARN-seq obtenues à partir de cellules THP1 traitées ou non par le PA et en présence ou en absence de Ro60, en réduisant l'analyse sur les gènes ciblés par Ro60 et trouvés par ChIP-seq. Nos résultats indiquent qu’après 6h de traitement avec du PA, Ro60 favorise significativement la transcription de 247 gènes cibles qui régulent la réponse inflammatoire. Nous avons validé le contrôle direct sur trois gènes cibles (TRIM62, ZEB1 et CPT1A) en utilisant des cellules THP1 où l’expression de la protéine Ro60 a été réduite ou non de manière stable. Enfin, pour identifier les partenaires moléculaires qui contribueraient à cette nouvelle fonction de Ro60, nous avons réalisé une analyse LC/MS/MS quantitative label-free à partir des complexes immunoprécipités contenant Ro60 dans des cellules THP-1 non traitées ou pas. Nous avons constaté que Ro60 interagit avec les composants des complexes TREX (TRanscription et EXport) et nucléopores (THOC1, THOC4 et TPR). THOC4 interagit directement avec Ro60. Ces résultats ont soulevé la possibilité que Ro60 régulerait la transcription et l'exportation des produits de transcription impliqués dans la réponse inflammatoire dans les macrophages grâce à son association avec le TREX. Nous avons donc effectué l'analyse EISA dans les cellules THP-1 traitées ou pas par le PA, en présence ou en absence de THOC4, et avons constaté que la synthèse de 25 transcrits, y compris TRIM62, ZEB1 et CPT1A, était régulée à la baisse en absence de THOC4 et de Ro60. En conclusion, nous avons caractérisé une nouvelle fonction associée à la chromatine de Ro60, qui se lie à THOC4 pour réguler le programme d'expression génique des macrophages chargés de lipides. L'altération de ce nouveau mécanisme chez les patients LED/SS pourrait favoriser l'état inflammatoire global et le risque plus élevé de rencontrer des accidents cardiovasculaires. En plus de fournir de nouvelles informations sur la régulation de l'expression génétique, l'impact plus large de ce projet réside dans l'opportunité de fournir de nouvelles données étiologiques pour les patients atteints de LED et de SSRo60, an RNA-binding protein that associates with YRNAs, is a clinical target of the immune response in patients with systemic lupus erythematosus (SLE) and Sjogren’s syndrome (SS). SLE and SS autoantibodies, including the anti-Ro60 autoantibody, penetrate inside the cells and localize in the nucleus. Interestingly, mice lacking Ro60 develop an autoimmune syndrome and pro-inflammatory status with features of SLE, indicating that Ro60 loss-of-function is involved in SLE pathogenesis. SLE and SS patients mainly die of premature inflammatory cardiovascular disorders caused by accelerated atherosclerosis. Based on these observations, we hypothesized that inflammation and cardiovascular accidents in SLE/SS patients would be caused by the dysfunction of Ro60 complex in the nucleus. During my PhD, we showed that in human and mouse primary macrophages and THP-1 cells (human monocytic cell line) stimulated with pro-inflammatory and pro-atherogenic stimuli (lipidladen macrophages), YRNA degradation allows Ro60 to bind chromatin in an RNA-independent fashion. To identify Ro60 binding sites on chromatin, we performed ChIP-seq analysis and found a significant increase of Ro60 binding upon palmitic acid (PA) treatment on promoters of coding genes, indicating that Ro60 could be involved in their transcription. By de novo motif discovery, we found two binding motifs that were significantly enriched in Ro60-binding sites. Next, to study the function of chromatin-associated Ro60 on its target genes, we performed RNA-seq in time course experiments on PA-treated and untreated THP1 cells, in presence or absence of Ro60. After, on the RNA-seq data obtained, we performed Exon-Intron Split analysis (EISA), a bioinformatic approach to quantify transcriptional and post-transcriptional regulation of gene expression from RNA-seq data of time course experiments. Our results indicate that Ro60 significantly promotes the transcription of 247 target genes that regulate inflammatory response upon 6h of PA treatment. We validated the direct control on three target genes (TRIM62, ZEB1 and CPT1A) by using a stably viral infected sh-Ro60-THP1 cells and control. On the other hand, by GO-term analysis performed on the RNA-seq data, we found that Ro60 knockdown overall promotes a pro-inflammatory phenotype in PA-treated Mo. Lastly, to identify Ro60 molecular partners that would contribute to this chromatin-associated function in lipid-laden macrophages, we performed a label-free quantitative LC/MS/MS analysis from the immunoprecipitated Ro60-containing complex in PA-treated and untreated THP-1 cells. We found that Ro60 interacts with components of the TREX (TRanscription and EXport) and nucleopore complexes, including THOC1, THOC4 and TPR. By performing co-IP experiments, we showed that THOC4 directly interacts with Ro60 on the chromatin and full cell extract. These results raised the possibility that Ro60 would directly regulate the transcription and export of transcripts involved in the inflammatory response in lipid-laden macrophages through its association with the TREX complex. We thus performed the EISA analysis in PA-treated and untreated THP-1 cells upon THOC4 knockdown and control and found that the synthesis of 25 transcripts, including TRIM62, ZEB1, and CPT1A, was downregulated in both THOC4 and Ro60 knockdown. In conclusion, we characterized a novel chromatin-associated function of Ro60, which associates with THOC4 to regulate the gene expression program of lipid-laden macrophages. The impairment of this new Ro60-dependent mechanism in SLE/SS patients by the nuclear penetration of anti-Ro60 autoantibodies in Mo/Ma could promote the overall inflammatory status of these patients and the higher cardiovascular accidents risk. In addition to provide new insights into regulated gene expression programs, the broader impact of this project resides in an opportunity to provide new etiological inputs for SLE and SS patients
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Wagner, Magali. "Impact des traitements hydrothermiques sur les propriétés techno-fonctionnelles de produits céréaliers." Thesis, Montpellier, SupAgro, 2010. http://www.theses.fr/2010NSAM0028/document.
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L'impact de traitements hydrodrothermiques complémentaires au procédé classique de fabrication des pâtes alimentaires a été étudié afin de définir les relations "procédé / structure / propriétés". Des pâtes 100% blé dur, éventuellement enrichies en protéines, monoglycérides et amylose, ont été produites, puis traitées à la vapeur selon différents couples temps-température, puis cuites de façon conventionnelle ou stérilisées. Les caractéristiques structurales des pâtes ainsi obtenues ont été étudiées à différentes échelles après chaque étape du procédé pour déterminer l'influence des opérations unitaires et de leurs paramètres. Les traitements vapeur induisent principalement une perte de la structure cristalline d'amidon natif, la formation de complexes amylose-lipides avec l'augmentation de la température et de la teneur en eau des pâtes. De plus, la réticulation du réseau protéique est accrue avec la température et la durée du traitement. Ces modifications structurales ont été synthétisées dans un digramme d'état. Toutefois, lorsque les pâtes sont chauffées en excès d'eau, le réseau protéique peut être rompu, les complexes disparaître et l'amylopectine rétrograder. La mesure des propriétés de texture de ces produits a permis d'établir les contributions respectives du mécanisme de plastification par l'eau et des différentes entités structurales présentes dans la pâte. Ces dernières renforcent mécaniquement les pâtes et l'addition des ingrédients permet ainsi d'améliorer les propriétés des produits. Un diagramme de fabrication a été proposé à partir de l'ensemble des résultats obtenus et son application à une formulation appropriée devrait permettre de répondre à l'objectif technique de ces travauxThe impact of hydrothermal treatments in addition to those of traditional process of pasta manufacturing has been studied to define the relationship "process / structure / properties". Pasta exclusively based on durum wheat semolina and other enriched in protein, amylose and lipids, were produced and then steamed for different time-temperature values, then boiled or sterilized. The structural characteristics of pasta were studied at different scales after each step of the process to determine the influence of unit operations and their parameters. The steam treatments mostly induce a loss of the crystal structure of native starch and the formation of complexes amylose-lipids with increasing temperature and moisture content of pasta. Moreover, the protein network was enhanced by cross-linking as much as temperature and duration of treatment increased. Theses structural changes are synthesized in a states diagram. When the pasta is heated in an excess of water, the protein network can be disrupted, complexes may disappear and amylopectine retrograde. The measurement of the rheological properties of these products have helped to assign the contribution of the mechanism of plasticization by water and of the presence of these structures. These latter mechanically reinforce the pasta and the additions of various ingredients may then improve their properties. based on these overall results, a diagram of the process has been proposed and its application with an appropriate formulation could allow to meet the technical objective of this work
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Cruz, Sanchez Fabiola A. "Synthesis and self-assembly of novel lipid platinum complexes." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2007. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Sears, Randy Bryan. "Permeability of POPC bilayer by dirhodium complexes." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1194529853.
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Aaron, Coey T. "A Complete Guide for Working with KCNE1 in Lipid Bilayers." Miami University Honors Theses / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=muhonors1303446195.
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Brisard, Daphné. "Etude de la maturation ovocytaire chez les vaches : effet de l'haplotype pour QTL-FERT-F-BTA3 et effet du métabolisme lipidique." Thesis, Tours, 2014. http://www.theses.fr/2014TOUR4003.
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Chez la vache Prim’Holstein, un QTL de fertilité a été localisé sur le chromosome 3, et deux haplotypes ont été déterminés : « Fertil+ » et « Fertil- ». Les « Fertil- » ont un plus fort taux d’échec de gestation précoce. Le 1er objectif de cette thèse était de déterminer si un dysfonctionnement des complexes ovocyte-cumulus (COC) pouvait expliquer l’échec précoce de gestation chez les « Fertil- ». L’analyse révèle un retard de maturation, une dérégulation de gènes appartenant aux voies des prostaglandines et des MAPK, et à la famille des Tribbles dans les CC ou l’ovocyte des « Fertil- ». Trois gènes composent la famille des Tribbles chez le bovin: TRIB1, TRIB2 et TRIB3, leur fonction est indéterminée dans le COC. Le 2nd objectif était de caractériser le patron d’expression des Tribbles et leur(s) fonction(s) au sein du COC bovin. Les Tribbles joueraient un rôle dans le métabolisme lipidique et l’inflammation au niveau folliculaire. Le métabolisme lipidique au sein du COC bovin étant peu caractérisé, le 3ème objectif était d’appréhender les profils des gènes du métabolisme des acides gras (AG) dans les CC au cours de la maturation. Ainsi, les CC expriment les gènes lipotytiques et lipogéniques. Enfin, la β-oxydation des AG est une fonction primordiale pour la maturation ovocytaireIn Prim’Holstein cow, a fertility QTL was localized on chromosome 3 and two haplotypes were determined: « Fertil+ » and « Fertil- ». « Fertil- » have a higher early pregnancy failure rate. The 1st objective of the thesis was to define if complex oocyte-cumulus COC dysfunction could explain the early pregnancy failure in « Fertil- ». Analysis highlighted a maturation delay, a dysregulation of genes involved in prostaglandin and MAPK pathway along with one member of the Tribbles family in « Fertil- » CC or oocyte. In bovine, the Tribbles family is composed of three genes: TRIB1, TRIB2 and TRIB3, their function is unknown within the COC. The 2nd objective was to characterize the Tribbles expression pattern and their function in the bovine COC. The tribbles might play a role in lipid metabolism and in inflammation at the follicular level. Lipid metabolism within bovine COC is poorly understood, thus the third objective was to apprehend fatty acid (FA) genes pattern in CC during maturation. Thus, CC express lipolytic and lipogenic genes. Lastly, FA β oxidation is found to be important for oocyte maturation
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Holdbrook, Daniel. "Molecular dynamics studies of transmembrane proteins within complex lipid environments." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/366965/.
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The interactions between lipids and proteins are crucial for many cellular processes. Typically, the nature of these interactions is studied in simple model lipid bilayers, which lack the complexity and heterogeneity of in vivo systems. Thus, this thesis investigates the impact of the lipid bilayer composition on protein dynamics and function. Both coarse grain and atomistic molecular dynamics simulations have been used to model membranes that contain lipid compositions approximating those found in vivo. The influence of these complex lipid environments on the dynamics of α-helical and β-barrel membrane protein is investigated. In particular, coarse grained simulations of a bilayer composed of a complex mixture of lipids, representing the Golgi apparatus, were used to identify preferential interactions of a helical transmembrane peptide with PIP2 lipids. Furthermore, atomistic molecular dynamics simulations have been used to identify several behaviour altering interactions between lipopolysaccharide, which is a key component of the Gram-negative bacterial outer membrane, and two outer membrane proteins, Hia and FecA. Lastly, coarse grained unilamellar vesicles, containing a complex mixture of phospholipids, were simulated in order to investigate protein aggregation and the short-term anomalous diffusion of lipids.
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Okome-Mintsa, Madeleine. "Etude des lipides complexes dans les sols acides : structure et origine." Poitiers, 1991. http://www.theses.fr/1991POIT2271.
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Dans les sols acides, l'activite biologique est reduite et les lipides tendent a s'accumuler. Une part importante des deux pools lipidiques du sol est constituee d'une fraction polaire ou lipides complexes, qui n'est pas directement analysable. Le but de ce travail est la determination de la structure (et l'origine) de cette fraction, par degradation chimique. L'utilisation de catalyseurs de transfert de phase permet d'ameliorer le rendement de l'hydrolyse et de la fraction polaire libre ou associee. Les monoacides obtenus proviennent de l'incorporation des acides simples dans cette fraction. Les autres lipides liberes, hydroxyacides, diacides, alcools, acides hopaniques sont plutot des elements intrinseques d'une matrice polaire. Les hydrocarbures deuteries obtenus apres traitement bbr#3-liald#4 semblent confirmer que cette matrice correspond a des biopolymeres, d'origine vegetale et microbienne. L'incorporation de sterols s'accompagne de leur reduction bien connue dans les sediments recents. Un equilibre lipide simples lipides complexes semble exister. Cet equilibre doit etre rapide dans les sols actifs et deplace vers la droite en milieu pauvre ou les lipides tendent a s'accumuler. Cette etude met en evidence une analogie certaine entre la matiere organique sedimentaire et cette fraction lipides polaires des sols, fraction que l'on peut donc assimiler a un protokerogene
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Bouna, Moussa Tandia. "Interaction des complexes lipides cationiques / ADN avec les composants du plasma." Doctoral thesis, Universite Libre de Bruxelles, 2005. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211013.
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Ham, Bryan Melvin. "Development of mass spectrometric methods for the analysis of components and complex interactions in biological systems." ScholarWorks@UNO, 2005. http://louisdl.louislibraries.org/u?/NOD,237.
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Thesis (Ph. D.)--University of New Orleans, 2005.Title from electronic submission form. "A dissertation ... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry"--Dissertation t.p. Vita. Includes bibliographical references.
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Molina, Salinas Marion Del Carmen. "Studies on the stabilization of lyophilized lipid/DNA complexes during storage /." Connect to abstract via ProQuest. Full text is not available online, 2007.
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Lepoittevin, Jean-Pierre. "Phenols, diphenols et cyclohexanediols a longues chaines derives d'allergenes naturels." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13103.
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Synthese par une nouvelle methode totalement stereoselective de trans,trans alkyl-3 cyclohexanediols-1,2. Synthese du cis,trans pentadecyl-3 cyclohexanediol-1,2. Activite allergisante et tolerogenique, vis a vis de l'urushiol de ces composes. Approche de la synthese de trans,trans alcenyl-3 cyclohexanediol-1,2. Isolement et structure des principaux composes aromatiques et lipidiques de ginkgo biloba l. Isolement et structure de nouvelles (-) alkyl-3 hydroxy-8 dihydro 3,4 isocoumarines. Isolement et structure de nouveaux nonacosanesdiols. Oxydation en position non activee, par l'acide metachloroperbenzoique des acides anacardiques et des cardanols. Activite allergisante des principaux aromatiques de ginkgo biloba l. Synthese d'un catechol porteur d'un complexe tris-bipyridyle du ruthenium comme sonde de microscopie electronique
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Beaslas, Olivier. "DÉTECTION DES LIPIDES ALIMENTAIRES SOUS FORME DE COMPLEXES MICELLAIRES PAR LES ENTÉROCYTES." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2008. http://tel.archives-ouvertes.fr/tel-00811592.
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L'intestin assure l'absorption des lipides alimentaires et doit faire face aux variations d'apport en lipides, entre les périodes inter-prandiales et post-prandiales. J'ai donc étudié dans les cellules Caco-2/TC7, la réponse des entérocytes à différents modes d'apports en lipides. Par une approche transcriptomique, j'ai montré que les lipides modulent l'expression de nombreux gènes entérocytaires. Les profils géniques obtenus diffèrent entre l'apport luminal ou sérique en lipides. La comparaison des apports apicaux de micelles inter- ou post-prandiales (MPP) a montré que les MPP modulent spécifiquement l'expression de 46 gènes majoritairement impliqués dans la transduction de signaux, le métabolisme lipidique, et l'architecture cellulaire. Ces résultats, s'ajoutant aux effets spécifiques des MPP obtenus dans l'équipe, suggéraient une détection entérocytaire des lipides alimentaires apportés par ces MPP. J'ai alors montré que les MPP se lient à une protéine dont le poids moléculaire correspond à celui du récepteur SR-BI, induisant sa clusterisation à la membrane apicale et son adressage vers les rafts. Seules les MPP induisent, le trafic de l'apoB, de la membrane apicale vers les compartiments sécrétoires et l'activation de kinases. Ces effets sont abolis quand SR-BI est bloqué par un de ses ligands ou invalidé par ARN interférence. Ces travaux montrent pour la première fois que les entérocytes sont capables de détecter spécifiquement les lipides alimentaires sous forme micellaire. Cette détection implique SR-BI et induit des voies de signalisation aboutissant à la mise en place de paramètres morphologiques et fonctionnels nécessaires au transfert des lipides alimentaires.
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Béaslas, Olivier. "Détection des lipides alimentaires sous forme de complexes micellaires par les entérocytes." Paris 6, 2008. https://tel.archives-ouvertes.fr/tel-00811592.
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L'intestin assure l'absorption des lipides alimentaires et doit faire face aux variations d’apport en lipides, entre les périodes inter-prandiales et post-prandiales. J'ai donc étudié dans les cellules Caco-2/TC7, la réponse des entérocytes à différents modes d'apports en lipides. Par une approche transcriptomique, j'ai montré que les lipides modulent l'expression de nombreux gènes entérocytaires. Les profils géniques obtenus diffèrent entre l’apport luminal ou sérique en lipides. La comparaison des apports apicaux de micelles inter- ou post-prandiales (MPP) a montré que les MPP modulent spécifiquement l’expression de 46 gènes majoritairement impliqués dans la transduction de signaux, le métabolisme lipidique, et l'architecture cellulaire. Ces résultats, s’ajoutant aux effets spécifiques des MPP obtenus dans l’équipe, suggéraient une détection entérocytaire des lipides alimentaires apportés par ces MPP. J'ai alors montré que les MPP se lient à une protéine dont le poids moléculaire correspond à celui du récepteur SR-BI, induisant sa clusterisation à la membrane apicale et son adressage vers les rafts. Seules les MPP induisent, le trafic de l’apoB, de la membrane apicale vers les compartiments sécrétoires et l’activation de kinases. Ces effets sont abolis quand SR-BI est bloqué par un de ses ligands ou invalidé par ARN interférence. Ces travaux montrent pour la première fois que les entérocytes sont capables de détecter spécifiquement les lipides alimentaires sous forme micellaire. Cette détection implique SR-BI et induit des voies de signalisation aboutissant à la mise en place de paramètres morphologiques et fonctionnels nécessaires au transfert des lipides alimentaires.
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Morel, Etienne. "Trafic et adressage protéique dans les entérocytes : cas de l'apolipoprotéine B et de la protéine cellulaire du prion." Paris 6, 2003. http://www.theses.fr/2003PA066231.
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Sato, Mariana Rillo [UNESP]. "Carreadores lipídicos nanoestruturados para incorporação de complexos de cobre(ii) aplicáveis no estudo frente ao Mycobacterium tuberculosis." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/134326.
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Tuberculosis (TB) is known worldwide as the leading infectious disease of chronic evolution in which the abandonment of treatment before the recommended period tends to cause the development of more severe disease, such as the appearance of resistant strains. Copper interacts with biologically active ligands developing copper(II) complex with activities antimicrobial. Nanostructured lipid carriers (NLCs) have gained prominence in the pharmaceutical field, since they have the ability to compartmentalize efficiently lipophilic drugs and modify their properties and behavior in the biological environment. The aims of this study was to evaluate the potential of copper(II) complexes-loaded NLCs applicable in the study against Mycobacterium tuberculosis. Copper(II) complexes containing isoniazid binder were obtained and they were entitled C1, C2, and C3 where they have co-binders anionic chloride, cyanate and thiocyanate, respectively. NLCs were obtained by fusion-emulsification technique, formulations were obtained by Ultra turrax at 5000 rpm for 10 minutes followed by sonicator at 8% amplitude for 20 minutes to obtain stable NLCs, those were incorporated of 3.50% and 0.50% to surfactant poloxamer 407 and cetrimonium bromide, respectively, and 2.07%, 2.50% and 0.88% of polyoxyethylene stearate lipids, triglycerides of capric acid/caprylic and ethoxylated hydrogenated castor oil 40 OE (F32) or castor oil (F38), respectively. Copper(II) complexes were incorporated into NLCs (F32.OE.C1, F32.OE.C2, F32.OE.C3 and F38.OR.C1, F38.OR.C2, F38.OR.C3) and characterized by diameter (Dmn) , polydispersivity index (PDI) and zeta potential (ZP) for 1, 15, 30, 45 and 60 days, which revealed homogeneous dispersion and excellent physical stability over the same period; the atomic force microscopy confirmed that developed NLCs are spherical particles dispersions at nanometer scales; differential scanning calorimetry revealed that the constituents used in the formulations interacted in the systems and confirmed that copper(II) complexes were incorporated in the NLCs. The antimicrobial activity of the complexes against M. tuberculosis H37Rv was determined by the resazurin microdilution assay demonstrated potential anti-TB when complexes were incorporated into NLCs. Cytotoxicity assay in murine macrophage-like cells J774A.1 (ATCC TIB-67) e MRC-5 (ATCC-CCL-171) for 24 h and acute toxicity of the complex against Artemia salina L (Artemiidae) showed the formulations have toxicity in all tested concentrations; although published reports indicated the safety of the components used of the formulations, studies should be conducted in animal models to assess the acute toxicity. These results suggest that NLCs have potential application in the study against Mycobacterium tuberculosis.
A Tuberculose (TB) é mundialmente conhecida como a principal doença infecto-contagiosa de evolução crônica, em que o abandono do tratamento antes do período recomendado tende a ocasionar o desenvolvimento de casos mais graves da doença, gerando o aparecimento de cepas resistentes. O cobre interage com ligantes biologicamente ativos desenvolvendo complexos de cobre(II) com ações antimicrobiana. Carreadores lipídicos nanoestruturados (CLNs) vêm se destacando na área farmacêutica, pois apresentam a capacidade de compartimentalizar, de maneira eficiente fármacos lipofílicos e de modificar suas propriedades e comportamento em meio biológico. O objetivo deste trabalho foi avaliar o potencial de CLNs acrescidos de complexos de cobre(II) aplicáveis no estudo frente ao Mycobacterium tuberculosis. Foram obtidos 3 complexos de cobre(II), intitulados C1, C2 e C3 que contem o ligante isoniazida e os co-ligantes aniônicos cloreto, tiocianato e cianato, respectivamente. Os CLNs foram obtidos pela técnica de fusão-emulsificação, testando-se diversas formulações por Ultra turrax a 5000 rpm por 10 minutos e por sonicador com amplitude 8% por 20 minutos até a obtenção de CLNs estáveis, que foram constituídos de 3,50% e 0,50 % de poloxamer 407 e brometo de cetrimônio, respectivamente, e de 2,07%, 2,50% e 0,88% de estearato de polioxietileno, triglicérides do ácido cáprico/caprílico e óleo de rícino hidrogenado e etoxilado 40 (F32) ou óleo de rícino (F38), respectivamente. Os complexos de cobre(II) foram incorporados nos CLNs (F32.OE.C1, F32.OE.C2, F32.OE.C3, e F38.OR.C1, F38.OR.C2, F38.OR.C3), e caracterizados por diâmetro hidrodinâmico médio (Dnm), índice de polidispersidade (IPD) e potencial zeta (PZ) por 1, 15, 30, 45 e 60 dias, revelando homogeneidade da dispersão e excelente estabilidade física; a microscopia de força atômica confirmou que os CLNs tratam-se de dispersões de partículas esféricas em escalas nanométricas; a calorimetria exploratória diferencial revelou que os componentes utilizados nas formulações interagiram para formação do sistema e que os complexos de cobre(II) foram incorporados nos CLNs. A atividade antimicrobiana dos complexos, frente ao M. tuberculosis H37Rv determinada pelo ensaio de microdiluição com Resazurina evidenciaram potencialização da ação anti-TB pela incorporação dos complexos nos CLNs. Os ensaios de citotoxicidade frente à linhagem de macrófagos J774A.1 (ATCC TIB-67) e de MRC-5 (ATCC-CCL-171) em 24 h e a toxicidade aguda dos complexos frente à Artemia salina L., mostraram que as formulações apresentaram toxicidade em todas as concentrações testadas; apesar de relatos da literatura indicarem a segurança dos componentes das formulações, estudos devem ser realizados em modelos animais para avaliar a toxicidade aguda. Os resultados sugerem que os CLNs apresentam aplicação potencial no estudo frente ao Mycobacterium tuberculosis.
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Clementi, Emily A. "Mechanistic insights into death induced by protein-lipid complexes in Streptococcus pneumoniae." Thesis, State University of New York at Buffalo, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3565732.
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Previous work has identified a protein-lipid complex from human milk (HAMLET) that effectively kills the prominent human respiratory bacterial pathogen Streptococcus pneumoniae (pneumococcus), and was serendipitously found to also kill tumor cells by inducing apoptosis. Two of the most attractive characteristics of HAMLET's bactericidal activity are that it employs a specific mechanism separate from common antibiotics, and pneumococci are unable to develop resistance to it in vitro. The objective of our studies was to develop a greater mechanistic understanding of HAMLET-induced death in the pneumococcus. Based on phenotypic parallels observed in bacteria and tumor cells following exposure to HAMLET, we hypothesized that HAMLET kills S. pneumoniae by binding to the surface and inducing an apoptosis-like pathway of death, including related ion transport events. In Part 1, we sought to elucidate mechanistic events that occur during this pathway, with a focus on the pneumococcal membrane, including membrane polarity and ion transport events. After establishing methods of monitoring these events using fluorescent indicator dyes and radioisotopes, we found that HAMLET dissipates the polarity and integrity of the pneumococcal membrane, and causes a sodium-dependent calcium influx that is required for death, which was effectively inhibited by both calcium and sodium transport inhibitors. The addition of kinase inhibitors also inhibited death, indicating a role for Ser/Thr kinases. Significantly, this mechanistic pathway appears to also be employed during starvation-induced death, as the same transport and kinase inhibitors also disrupted autolysis activation and biofilm formation. In additional studies, we found that pneumococcal death with these same mechanistic features can be induced by a related protein, equine lysozyme, in complex with oleic acid (ELOA). In Part 2, we explored the interaction of HAMLET with the pneumococcal surface and found that choline, a major component of cell surface teichoic acids, is important for HAMLET's bactericidal activity, as choline-free pneumococci were less susceptible to HAMLET-induced death and other mechanistic features including membrane perturbations and ion transport. Further studies showed that addition of exogenous lipoteichoic acid could effectively block HAMLET-induced death, suggesting that this molecule concentrates HAMLET at the surface to initiate its lethal activity. As the incidence of infections caused by antibiotic-resistant strains of S. pneumoniae continues to rise, developing a better understanding of HAMLET's bactericidal activity and the molecular targets and activities involved is important, as it has great potential to uncover new targets for antimicrobial intervention.
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Callow, Philip Austin. "Cationic lipid : DNA complexes - their structure and interactions with model cell membranes." Thesis, King's College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400591.
Full text
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Grippa, Alexandra 1980. "Control of lipid droplets biogenesis by the seipin complex in budding yeast." Doctoral thesis, Universitat Pompeu Fabra, 2015. http://hdl.handle.net/10803/385613.
Full textAbstract:
Most cells store energy in lipid droplets (LDs), specialized storage organelles composed of a neutral lipid core that, during their biogenesis, is packaged into a single phospholipid monolayer decorated with specific proteins. Regulation of LDs size and number requires the function of the conserved ER protein Seipin/Fld1, however the molecular function of this protein remains poorly understood. Yeast seipin Fld1 is in complex with Ldb16, an uncharacterized ER protein. Like fld1Δ cells, LDB16 deletion mutant displays a similar aberrant LDs morphology phenotype: lower number of supersized LDs (SLD) or tiny and clustered LD aggregates, depending on the absence or presence of the phospholipid precursor inositol in the media, respectively. The growth stage of cells also impacts on the relative distribution of these phenotypes: while LD aggregates predominate in dividing cells, SLDs are found primarily in stationary phase cells. We found that the complex formed by Ldb16 and Fld1 is required for normal LDs phenotype. In particular, this dual LD morphology is not observed for any other mutants studied so far suggesting that Fld1/Ldb16 have a unique role in LD biogenesis.
Combining mass spectrometry analysis on purified LDs with light microscopy, we found that the distribution of many ER and LDs proteins is altered in these mutants. Analysis of a subset of proteins enriched at LDs surface in mutant cells indicated that the physical properties of clustered LDs may differ from those of supersized LDs. Moreover our data obtained by following the process of LDs biogenesis in presence or absence of inositol points toward a role for Fld1/Ldb16 complex in organizing membrane domains at LDs assembly site. In the absence of the complex, the segregation between the two compartments could be lost and the assembly of LDs is impaired resulting in defects in phospholipid packing that is exacerbated in inositol presence. We propose a function in facilitating the establishment of LD identity by acting as a diffusion barrier at the ER-LD contact sitesLa mayoría de las células almacenan la energía en partículas lipídicas, también conocidas como “lipid droplets” (LD), unos orgánulos especializados compuestos por un núcleo de lípidos neutros que, durante su biogénesis, se empaqueta de forma coordinada en una monocapa de fosfolípidos decorada con proteínas específicas. La regulación del tamaño y número de LDs requiere la función de la proteína conservada de retículo endoplasmático (RE) Seipina/Fld1. Sin embargo, la función molecular exacta de esta proteína no está clara. La seipina/Fld1 de levadura está en complejo con Ldb16, una proteína de RE no caracterizada. Como las células fld1Δ, la deleción del gen correspondiente a esta proteína muestra la misma doble morfología aberrante de LDs: un LD individual y de tamaño gigante (SLD, “single and supersized LD”) o LDs pequeños y agrupados, en función de la ausencia o presencia, respectivamente, del precursor fosfolipídico inositol en el medio. La fase de crecimiento de las células también influye en la distribución relativa de estos fenotipos: mientras que los agregados de LDs predominan en las células en división, los SLDs se encuentran principalmente en células en fase estacionaria. Observamos que el complejo formado por Ldb16 y Fld1 es necesario para el fenotipo de LDs normal. En particular, esta doble morfología de LDs no se observa en ningún otro mutante estudiado hasta ahora, lo que sugiere que Fld1 / Ldb16 tiene un papel único en la biogénesis de LDs. Combinando el análisis de espectrometría de masas en LDs purificados con microscopía, se observó que la distribución de muchas proteínas de RE y LDs estaba alterada en estos mutantes. Los cambios observados en un subconjunto de proteínas enriquecidas en la superficie de las LDs, nos indicaron que las propiedades físicas de los LDs agrupados podrían diferir de las de los LDs gigantes. Los datos obtenidos siguiendo el proceso de biogénesis de LD sugieren que el complejo Fld1/Ldb16 organiza dominios de membrana en los sitios de ensamblaje de LDs, y en su ausencia la segregación entre RE y LDs pueden perderse. Proponemos que la función del complejo Fld1/Ldb16 es facilitar el establecimiento de la identidad del LD, actuando como una barrera de difusión en los sitios de contacto RE-LD.
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Negrin, Kimberly A. "Complex Roles of Macrophages in Lipid Metabolism and Metabolic Disease: A Dissertation." eScholarship@UMMS, 2004. http://escholarship.umassmed.edu/gsbs_diss/713.
Full textAbstract:
The worldwide prevalence of obesity and metabolic disease is increasing at an exponential rate and current projections provide no indication of relief. This growing burden of obesity-related metabolic disorders, including type 2 diabetes mellitus (T2DM), highlights the importance of identifying how lifestyle choices, genetics and physiology play a role in metabolic disease and place obese individuals at a greater risk for obesity-related complications including insulin resistance (IR). This increased risk of IR, which is characterized by a decreased response to insulin in peripheral tissues including adipose tissue (AT) and liver, is associated with a chronic, low grade inflammatory state; however, the causative connections between obesity and inflammation remains in question. Experimental evidence suggests that adipocytes and macrophages can profoundly influence obesity-induced IR because adipocyte dysfunction leads to ectopic lipid deposition in peripheral insulin sensitive tissues, and obese AT is characterized by increased local inflammation and macrophage and other immune cell populations. Attempts to delineate the individual roles of macrophage-derived pro-inflammatory cytokines, like tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β), have demonstrated causative roles in impaired systemic insulin sensitivity, adipocyte function and hepatic glucose and lipid metabolism in obese animal models. Thus, the attenuation of macrophage-derived inflammation is an evolving area of interest to provide insight into the underlying mechanism(s) leading to obesity-induced IR.
Thus, in the first chapter of this thesis, I describe experiments to refine the current paradigm of obesity-induced AT inflammation by combining gene expression profiling with computational analysis of two anatomically distinct AT depots, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) to address whether the inflammatory signature of AT is influenced by diet-induced obesity (DIO). Microarray and qRT-PCR analysis data revealed that DIO mouse SAT is resistant to high fat diet (HFD)-induced inflammation and macrophage infiltration, and our data support the current model of obesity-induced visceral adipose tissue macrophage (VATM) enrichment. Our data demonstrated robust increases in VAT pro-inflammatory cytokine expression, which are consistent with the significant increases in macrophage-specific gene expression and consistent with previous reports in which VAT inflammation is enhanced and attributed to classically activated (M1) macrophage infiltration. However, these data are only observed relative to the expression of invariant housekeeping gene expression. When M1-specific genes are expressed relative to macrophage-specific standards like F4/80 expression, these inflammatory makers are unchanged. These data indicate that the changes in the overall inflammatory profile of DIO mouse VAT is because of quantitative changes in adipose tissue macrophage (ATM) number and not qualitative changes in activation state. These observations are consistent with the idea that infiltrating ATMs may have roles other than the previously described role in mediating inflammation in obese adipose tissue.
Hepatic IR occurs partly as a consequence of adipocyte dysfunction because the liver becomes a reservoir for AT-derived fatty acids (FAs), which leads to obesity-related non-alcoholic fatty liver disease (NAFLD). In the second part of my thesis, I used clodronate liposome-mediated macrophage depletion to define the role of macrophages in hepatic lipid metabolism regulation. We discovered that i.p. administration of clodronate liposomes depletes Kupffer cells (KCs) in ob/ob mice without affecting VATM content, whereas clodronate liposomes depletes both KCs and VATMs in DIO mice. To this end, we established that clodronate liposome-mediated KC depletion, regardless of VATM content in obese mice, abrogated hepatic steatosis by reducing hepatic de novo lipogenic gene expression. The observed reductions in hepatic inflammation in macrophage-depleted obese mice led to the hypothesis that IL-1β may be responsible for obesity-induced increased hepatic triglyceride (TG) accumulation. We determined that IL-1β treatment increases fatty acid synthase (Fas) protein expression and TG accumulation in primary mouse hepatocytes. Pharmacological inhibition of interleukin-1 (IL-1) signaling by interleukin-1 receptor antagonist (IL-1Ra) administration recapitulated these results by reducing hepatic TG accumulation and lipogenic gene expression in DIO mice. Thus, these data highlight the importance of the inflammatory cytokine IL-1β in obesity-driven hepatic steatosis and suggests that liver inflammation controls hepatic lipogenesis in obesity.
To this end, the studies described herein provide new insight and appreciation to the multi-functional nature of macrophages and clinical implications for anti-inflammatory therapy in obesity and NAFLD treatment. We demonstrate the complexities of macrophage-mediated functions in insulin sensitive tissues and a role for obesity-induced inflammatory cytokine IL-1β in hepatic lipid metabolism modulation, which is reversed via IL-1Ra intervention. The use of anti-inflammatory therapy to ameliorate obesity-associated NAFLD was perhaps the most important contribution to this body of work and is full of promise for future clinical application. It is likely that the future of therapeutics will be multi-faceted and combine therapeutic approaches to enhance glucose tolerance and overall health in obese, IR and T2DM patients.
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Negrin, Kimberly A. "Complex Roles of Macrophages in Lipid Metabolism and Metabolic Disease: A Dissertation." eScholarship@UMMS, 2014. https://escholarship.umassmed.edu/gsbs_diss/713.
Full textAbstract:
The worldwide prevalence of obesity and metabolic disease is increasing at an exponential rate and current projections provide no indication of relief. This growing burden of obesity-related metabolic disorders, including type 2 diabetes mellitus (T2DM), highlights the importance of identifying how lifestyle choices, genetics and physiology play a role in metabolic disease and place obese individuals at a greater risk for obesity-related complications including insulin resistance (IR). This increased risk of IR, which is characterized by a decreased response to insulin in peripheral tissues including adipose tissue (AT) and liver, is associated with a chronic, low grade inflammatory state; however, the causative connections between obesity and inflammation remains in question. Experimental evidence suggests that adipocytes and macrophages can profoundly influence obesity-induced IR because adipocyte dysfunction leads to ectopic lipid deposition in peripheral insulin sensitive tissues, and obese AT is characterized by increased local inflammation and macrophage and other immune cell populations. Attempts to delineate the individual roles of macrophage-derived pro-inflammatory cytokines, like tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β), have demonstrated causative roles in impaired systemic insulin sensitivity, adipocyte function and hepatic glucose and lipid metabolism in obese animal models. Thus, the attenuation of macrophage-derived inflammation is an evolving area of interest to provide insight into the underlying mechanism(s) leading to obesity-induced IR.
Thus, in the first chapter of this thesis, I describe experiments to refine the current paradigm of obesity-induced AT inflammation by combining gene expression profiling with computational analysis of two anatomically distinct AT depots, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) to address whether the inflammatory signature of AT is influenced by diet-induced obesity (DIO). Microarray and qRT-PCR analysis data revealed that DIO mouse SAT is resistant to high fat diet (HFD)-induced inflammation and macrophage infiltration, and our data support the current model of obesity-induced visceral adipose tissue macrophage (VATM) enrichment. Our data demonstrated robust increases in VAT pro-inflammatory cytokine expression, which are consistent with the significant increases in macrophage-specific gene expression and consistent with previous reports in which VAT inflammation is enhanced and attributed to classically activated (M1) macrophage infiltration. However, these data are only observed relative to the expression of invariant housekeeping gene expression. When M1-specific genes are expressed relative to macrophage-specific standards like F4/80 expression, these inflammatory makers are unchanged. These data indicate that the changes in the overall inflammatory profile of DIO mouse VAT is because of quantitative changes in adipose tissue macrophage (ATM) number and not qualitative changes in activation state. These observations are consistent with the idea that infiltrating ATMs may have roles other than the previously described role in mediating inflammation in obese adipose tissue.
Hepatic IR occurs partly as a consequence of adipocyte dysfunction because the liver becomes a reservoir for AT-derived fatty acids (FAs), which leads to obesity-related non-alcoholic fatty liver disease (NAFLD). In the second part of my thesis, I used clodronate liposome-mediated macrophage depletion to define the role of macrophages in hepatic lipid metabolism regulation. We discovered that i.p. administration of clodronate liposomes depletes Kupffer cells (KCs) in ob/ob mice without affecting VATM content, whereas clodronate liposomes depletes both KCs and VATMs in DIO mice. To this end, we established that clodronate liposome-mediated KC depletion, regardless of VATM content in obese mice, abrogated hepatic steatosis by reducing hepatic de novo lipogenic gene expression. The observed reductions in hepatic inflammation in macrophage-depleted obese mice led to the hypothesis that IL-1β may be responsible for obesity-induced increased hepatic triglyceride (TG) accumulation. We determined that IL-1β treatment increases fatty acid synthase (Fas) protein expression and TG accumulation in primary mouse hepatocytes. Pharmacological inhibition of interleukin-1 (IL-1) signaling by interleukin-1 receptor antagonist (IL-1Ra) administration recapitulated these results by reducing hepatic TG accumulation and lipogenic gene expression in DIO mice. Thus, these data highlight the importance of the inflammatory cytokine IL-1β in obesity-driven hepatic steatosis and suggests that liver inflammation controls hepatic lipogenesis in obesity.
To this end, the studies described herein provide new insight and appreciation to the multi-functional nature of macrophages and clinical implications for anti-inflammatory therapy in obesity and NAFLD treatment. We demonstrate the complexities of macrophage-mediated functions in insulin sensitive tissues and a role for obesity-induced inflammatory cytokine IL-1β in hepatic lipid metabolism modulation, which is reversed via IL-1Ra intervention. The use of anti-inflammatory therapy to ameliorate obesity-associated NAFLD was perhaps the most important contribution to this body of work and is full of promise for future clinical application. It is likely that the future of therapeutics will be multi-faceted and combine therapeutic approaches to enhance glucose tolerance and overall health in obese, IR and T2DM patients.
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Almeida, Roberto Barbosa de. "Purification and characterization of LOX isoenzymes from germinating barley : biotransformation of complex lipids /." [S.l. : s.n.], 2005. http://www.gbv.de/dms/bs/toc/506584569.pdf.
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Myers, Elise McKenna. "Complex lipids in microbial mats and stromatolites of Hamelin Pool, Shark Bay, Australia." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/114126.
Full textAbstract:
Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 44-50).
Stromatolites, columnar rock-like structures, are potentially some of the oldest, microbially mediated fossils visible in the rock record; if biogenesis is able to be confirmed for these ancient stromatolites, some being greater than 3 billion years old, these ancient stromatolites could be used to demonstrate the microbial community assemblages throughout ancient time. Hamelin Pool, Shark Bay, Australia is an ideal field site for this task, as stromtolites and modern microbial mats coexist and the microbial mats have been shown to contribute to the formation of the stromatolites. Comprehensive lipid biomarker profiles were determined in this study for non-lithified smooth, pustular, and colloform microbial mats, as well as for smooth and colloform stromatolites. Intact polar lipids, glycerol dialkyl glycerol tetraethers, and bacteriohopanepolyols were analyzed via liquid chromatography-mass spectrometry (LC-MS) coupled to a Quadropole Time-of-Flight (QTOF) mass spectrometer, while the previously studied fatty acids (Allen et al., 2010) were analyzed using gas chromatography-mass spectrometry (GC-MS) to prove consistent signatures. From the lipid profiles, sulfate-reducing bacteria and anoxygenic phototrophic bacteria and archaea could be inferred. The presence of the rare 3-methylhopanoids was discovered in a significant portion of the samples, which could add to the characterization of this molecule, which has only been concretely linked to oxygenic conditions for formation. In accordance with Allen et al. in 2010, 2-methyhopanoids were detected, as well as limited signals from higher (vascular) plants. While the lipid profiles for all sediment types were similar, there were some differences that are likely attributable to morphological differences. However, the overall similarities suggest microbial communities can be similar between non-lithified microbial mats and stromatolites.
by Elise McKenna Myers.
S.B.
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Houston, Nicola Patricia. "Protein complexes in neurodegenerative diseases." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/7738.
Full textAbstract:
The 14-3-3 family of proteins are important signalling proteins involved in a number of cellular processes. These include cell cycle regulation, apoptosis, signal transduction and cell signalling. There is also considerable evidence in the literature that 14-3-3 proteins play a vital role in the pathology of neurodegenerative diseases, including Alzheimer’s, Parkinson’s, Huntington’s and Prion disease. The neurodegenerative disease of focus in this research is Spinocerebellar Ataxia Type 1 (SCA1). SCA1 is a polyglutamine-repeat disease and the interaction of the disease protein ataxin-1 with 14-3-3 proteins leads to the toxic accumulation and subsequent protein aggregation which is characteristic of this disease. This study focused on attempting to elucidate the structure of various domains of the disease protein and also in identifying potential inhibitors of this deleterious interaction. Unfortunately, structural studies were not successful due to a number of caveats encountered in the expression and purification of the ataxin-1 protein domains. By utilising computational methods and small molecule inhibitors, a number of potential lead compounds which possess the ability to at least partly disrupt the interaction of 14- 3-3ζ have been identified. As 14-3-3 proteins play roles in other neurodegenerative diseases, successful identification of potential drug lead treatments can have far reaching benefits in a number of neurodegenerative diseases including SCA1. Lipid rafts are also involved in neurodegenerative disease pathology. Lipid rafts are cholesterol and sphingolipid rich domains which organise the plasma membrane into discrete microdomains and act as signalling platforms and processing centres which attach specific proteins and lipids. A number of disease proteins are processed at these membrane regions, including those involved in Alzheimer’s, Parkinson’s and Prion disease. This processing is a step which is critical in the pathology of disease and abnormal processing leads to the formation of toxic protein aggregates. Previous research in the lab identified the association of low levels of the five main brain isoforms of 14-3-3 proteins with rafts. This study expanded on this to positively identify the presence of the two phospho-forms of 14-3-3, α and δ. The mechanism by which 14-3-3 proteins associate with rafts was also investigated, indicating that 14-3-3 associates with rafts via an unidentified raftbound protein(s). In addition, the phosphorylation status and quaternary structure of 14-3-3 in the presence of sphingolipids has been explored.
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Banerjee, Pallavi [Verfasser], Stefanie [Akademischer Betreuer] Barbirz, Mark [Akademischer Betreuer] Santer, Reinhard [Gutachter] Lipowsky, and Robert [Gutachter] Woods. "Glycosylphosphatidylinositols (GPIs) and GPI-anchored proteins tethered to lipid bilayers : modelling a complex interplay of carbohydrates, proteins and lipids / Pallavi Banerjee ; Gutachter: Reinhard Lipowsky, Robert Woods ; Stefanie Barbirz, Mark Santer." Potsdam : Universität Potsdam, 2021. http://d-nb.info/1225821576/34.
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Gueguinou, Maxime. "Complexe canalaires KCa/Ca sensibles aux éther-lipides : régulation de la signalisation calcique dans la migration de cellules cancéreuses." Thesis, Tours, 2015. http://www.theses.fr/2015TOUR4032.
Full textAbstract:
La formation de métastases est la cause majeure des décès par cancer. Le développement de métastases est consécutif à une série d‟événements complexes tels que la migration, l‟invasion et la prolifération cellulaire. Le canal potassique SK3 (membre de la famille des SKCa) régule la migration des cellules cancéreuses du sein et favorise le développement de métastases osseuses. Le but du projet était d‟identifier et de caractériser les voies d‟entrées calciques associées à la migration cellulaire dépendante du canal SK3 dans différents cancers (sein, colon et prostate). Nous avons pu mettre en évidence que les canaux Ca2+qui étaient associés au canal SK3 variaient en fonction du cancer et régulaient la migration cellulaire dépendante du canal SK3. De plus, nous avons montré que la localisation de ces complexes KCa/Ca2+ dans les radeaux lipidiques était importante pour leur régulation et leur fonction. Ainsi, la délocalisation de ces complexes hors des radeaux lipidiques par des alkyl-phospholipides est un moyen permettant de moduler la migration des cellules exprimant le canal SK3 et le développement de métastasesIn most cases of cancer, metastasis and not the primary tumor per se is the main cause of mortality. To establish secondary growth in distant organs cancer cells must develop an enhanced propensity to migrate. The key objective of this thesis proposes that some actors of Ca2+ signaling (Orai, and TRPC, STIM) coupled to SK3 channel would form complexes that play a critical role in cell migration of various cancers (breast, colon and prostate). Furthermore we showed that the localization of these channels complexes in lipid-rafts is essential to their regulation and function. Thus, the delocalization of these complexes of lipid-raft outside by alkyl-phospholipids could be a new way to modulate the SK3/Ca2+ dependent cell migration and metastasis development
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Muindi, K. M. "Cellular lipids and immunity : characterisation of glycolipids binding the antigen presenting molecule CD1." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670089.
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Jacquot, Aurore. "Co-expression et caractérisation fonctionnelle d’un transporteur de lipides (une « flippase ») de la levure S. cerevisiae : l’ATPase P4 Drs2p, en complexe avec sa sous-unité associée Cdc50p." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA11T081/document.
Full textAbstract:
Les membranes plasmiques et les membranes du trans-Golgi des cellules eucaryotes présentent une asymétrie des lipides qui les composent, avec les aminophospholipides (APLs : phosphatidylsérine et phosphatidyléthanolamine) enrichis dans le feuillet cytosolique. La dissipation de cette asymétrie est impliquée dans de nombreux processus (patho)physiologiques. Plusieurs études suggèrent que les ATPases P4 sont les candidats les plus probables pour le transport des APLs et le maintien de leur distribution asymétrique ; leur délétion dans la levure inhibe le trafic membranaire. En outre, des études ont montré que les ATPases P4 interagissaient avec les protéines de la famille CDC50 ; cette interaction est essentielle pour l’adressage et peut-être aussi la fonction des ATPases P4. Afin de contribuer à la compréhension du mécanisme de transport des lipides par les ATPases P4, l’objectif de ce travail a été de mettre au point la co-expression fonctionnelle, dans la levure, de l’ATPase P4 Drs2p et de sa protéine partenaire Cdc50p. Nous avons obtenu une fraction membranaire enrichie à 3% avec la protéine Drs2p, majoritairement en complexe avec Cdc50p. L’étude fonctionnelle du complexe nous a permis de mettre en évidence un rôle crucial du phosphatidylinositol-4-phosphate (PI(4)P), un important régulateur du trafic membranaire, au cours d’une étape particulière du cycle catalytique. Nous avons également développé un protocole de purification sur résine streptavidine du complexe Drs2p/Cdc50p. Enfin, comme un site potentiel d’interaction avec le PI(4)P est présent sur l’extrémité C-terminale de Drs2p, nous avons engendré différentes constructions de Drs2p, dans lesquelles une partie de l’extrémité C-terminale a été délétée ; dans une autre construction, l’extrémité N-terminale a également été délétée. Notre travail ouvre la voie à la caractérisation fonctionnelle et structurale détaillée du complexe Drs2p/Cdc50p, et à l’étude du rôle du transport de lipides dans le trafic membranaireTrans-Golgi membranes and plasma membranes of eukaryotic cells are asymmetric, with their cytosolic leaflet enriched in aminophospholipids (APLs: phosphatidylserine and phosphatidylethanolamine). Dissipation of this asymmetry is involved in many (patho)physiological processes. P4 ATPases are prime candidates for APL transport and for maintaining asymmetry across membranes. In addition, yeast deleted for P4 ATPases display membrane trafficking defects. Besides, CDC50 proteins have been shown to interact physically with P4 type ATPases, and this interaction is important for addressing the complex to the right destination, and possibly also for its function. To gain insight into the molecular mechanism of lipid transport by P4 ATPases, the goal of my thesis was to develop the co-expression, in yeast, of a functional P4 ATPase, Drs2p, together with its partner, Cdc50p. The strategy we developed allowed us to obtain a membrane fraction enriched in Drs2p (~3%), mainly in complex with Cdc50p. Functional characterization of the complex identified phosphatidylinositol-4-phosphate (PI4P), a major regulator of membrane trafficking, as a crucial component for rapid completion of the Drs2p/Cdc50p catalytic cycle. We also purified the complex in one step on streptavidin beads. Finally, we started investigating the potential auto-inhibitory roles of the C-terminus (as the C-terminus of Drs2p contains a PI4P binding site) and the N-terminus of Drs2p, by expressing various truncated versions of Drs2p. Our work sets the stage for detailed functional and structural characterization of the Drs2p/Cdc50p complex and its role in membrane traffic
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Martínez-Seara, Monné Hector. "Theoretical Study of Phospholipid Membranes: the Complex Role of Cholesterol and Lipid Unsaturation." Doctoral thesis, Universitat de Barcelona, 2010. http://hdl.handle.net/10803/35684.
Full textAbstract:
The Doctoral dissertation titled “Theoretical Study of Phospholipid Membranes: the Complex Role of Cholesterol and Lipid Unsaturation” covers biological membrane modeling by means of molecular dynamics.
The main focus of the dissertation is to study the role of phospholipid unsaturation and cholesterol in animal cell membrane properties. In general, it aims to find the molecular mechanisms underlying naturally occurring phenomena, such as the preference displayed by nature for phospholipids with an unsaturated sn-2 chain where the double bond is placed in its middle. Significant results were obtained regarding the importance of the double bond position in phospholipidic membranes. We report that lipids with a double bond in the middle of their acyl chain present the largest capacity to induce disorder in the membrane. We also found that this effect is enhanced when the unsaturated acyl chain is attached to the sn-2 lipid.
Another important result obtained in this work is the explanation of the role of cholesterol as promoter of in-plane ordering due to its collective action over surrounding phospholipids. We report the natural preference of cholesterol to be placed in the second coordination shell in the membrane plane in respect to other cholesterols. In other words cholesterols do not like to be in direct contact with each other. This result strongly supports the umbrella theory. Additionally we found that cholesterols place themselves in respect to the others in a well-defined 3 fold symmetry pattern. The combination of these two features is likely responsible for the condensation effect, as the ordering of the lipid tails could be explained by their sandwiching between cholesterols.
These results, never reported before, shed light on the reasons behind the natural lipid selection and the mechanism underlying the well-known ordering effects of cholesterol which are largely controversial.
Final part of this Doctoral dissertation focuses on membranes that contain cardiolipins instead of cholesterol like the one present in the mitochondria.L'objectiu principal d'aquesta tesi és estudiar el paper dels fosfolípids insaturats i del colesterol en les propietats de les membranes cel·lulars animals mitjançant dinàmica molecular clàssica. En general, s'han estudiat els mecanismes moleculars subjacents responsables de la preferència, dictada genèticament, per composicions lipídiques determinades en aquestes membranes. Per exemple, la preferència general pels fosfolípids insaturats amb un doble enllaç al mig de la cadena sn-2. Entre els resultats obtinguts destaquen les evidències trobades que justifiquen la importància de la posició del doble enllaç en els fosfolípids que constitueixen les membranes. S'ha observat que els fosfolípids insaturats amb un doble enllaç al mig de la cua presenten una major capacitat d'induir desordre en la membrana. Aquesta capacitat d'induir desordre es maximitza quan la cadena insaturada és la sn-2, posició genèticament afavorida. Un altre resultat important obtingut en aquest treball és l'explicació del paper del colesterol com a promotor d'ordre en el pla de la membrana a causa de la seva acció col·lectiva sobre els fosfolípids circumdants. Hem constatat la preferència natural del colesterol per col·locar-se en la segona esfera de coordinació en relació amb els altres colesterols adjacents. En altres paraules, al colesterol no li agrada estar en contacte directe amb altres colesterols. Aquest resultat dóna suport a la teoria del paraigües. A més, s'ha trobat que els colesterols s'emplacen entre ells formant un patró dinàmic amb simetria trigonal. Aquest resultat no és gens intuïtiu tenint en compte la naturalesa fluïda del medi i que els colesterols no es troben en contacte directe. La combinació d'aquestes dues característiques justifica el conegut efecte de condensació dels colesterols: colesterols adjacents ordenen les cues fosfolipídiques aixafant-les entre ells. Aquests resultats, fins ara desconeguts, aclareixen algunes de les raons existents darrere de la selecció natural dels lípids i els mecanismes responsables dels coneguts efectes de condensació que indueix el colesterol, que fins ara eren en gran mesura controvertits. Per acabar, aquesta tesi doctoral dedica el seu darrer capítol a l'estudi de membranes que contenen cardiolípids en comptes de colesterol, com és el cas de la membrana mitocondrial.
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Hou, Weimin. "Developing Mass Spectrometry-Based Analytical Methodologies for Analyzing Complex Protein and Lipid Samples." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/26134.
Full textAbstract:
Mass spectrometry has increasingly become the method of choice for the analysis of
complex biological samples, including proteins and lipids. This thesis describes the
development of MS-based analytical methodologies for the analysis of complex proteomic
and lipidomic samples.
Chapter 3 describes the development of microfluidic proteomic reactors, in the
formats of SCX reactor, SCX 96-well plate reactor, and SAX reactor, for the enzymatic
digestion of complex proteomic samples for subsequent LC-MS/MS analysis. These
microfluidic proteomic reactors greatly simplified the enzymatic digestion of complex
proteomic samples by combining multiple processing steps, such as rapid extraction and
enrichment of proteins. Furthermore, chemical and enzymatic treatments of proteins were all
performed in a few nanoliters effective volume, resulting in an increased protein digestion
efficacy. After the protein digestion process, the resulting peptides were eluted in buffers that
were compatible with HPLC-MS/MS analysis.
In chapter 4, a methodology based on nano-HPLC-ESI-MS/MS for the analysis of
PAF and LPC lipid species is described. In this method, lipid extracts from biological
samples were separated by nano-flow HPLC prior to being introduced into a Q-TRAP 2000
mass spectrometer, where the lipid species of interest were detected using a precursor ion
scan at m/z 184. Absolute quantitation of PAF family lipid species were performed with
standard addition method, where 5 standard solutions containing 0.2-1 ng each of C16:0,
C18:0 PAF and C16:0, C18:0 lyso-PAF were used in the experiment. Further, the spiking of
identical amount of non-endogenous C13:0 LPC at time of extraction allow the relative
comparisons of other LPC lipid species of interest between different samples. The developed
methods were employed to analyze the changes of PAF and LPC lipid species in NGFdifferentiated
PC12 cells, in the posterior/entorhinal cortex of AD patients and TgCRND8
transgenic mice, and over the course of 24 hour exposure of human hNT neurons to Aβ42
treatment, respectively, in comparison to controls.
iii
Chapter 5 describes the development of a novel shotgun lipidomic methodology for the determination of stereospecificity of diacyl glycerophospholipids including glycerophosphatidic acids (PA), glycerophosphoserines (PS), glycerophosphoglycerols (PG), glycerophosphoinositols(PI), and glycerophosphoethanolamines (PE), which can be conventionally ionized under negative ion mode. The stereospecificity of diacyl glycerophospholipids was determined based on the relative abundance of the lyso-form fragment ions, attributed to the neutral loss of fatty acyl moieties. The fragmentation patterns of a variety of diacyl glycerophospholipid standards were first fully examined over a wide range of collision energy. We observed that lyso-form fragment ions corresponding to the neutral loss of fatty acyl moieties attached to the sn2 position as free fatty acids ([M-Sn2]-) and as ketenes ([M-(Sn2-H2O)]-) exhibited consistently higher intensity than their counter part ions due to the neutral loss of fatty acyl moieties attached to the sn1 position ([M-Sn1]- and [M-(Sn1-H2O)]-). We then examined the product ion spectra of diacyl glycerophospholipids recorded from lipid extracts of rat hepatoma cells, where the stereospecific information of these lipids was conclusively determined.
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Carmon, Ophélie. "Etude des mécanismes moléculaires controlant la biogenèse des granules de sécrétion : Role de la chromogranine A, du complexe actomyosine et des lipides de la membrane golgienne." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR015/document.
Full textAbstract:
Les cellules neuroendocrines possèdent d’une part la voie de sécrétion constitutive, existant dans tous les types cellulaires, qui permet le renouvellement continu de la membrane plasmique et de la matrice extracellulaire, et d’autre part la voie de sécrétion régulée, spécifique aux cellules sécrétrices, qui permet la sécrétion d’hormones suite à la stimulation de la cellule. Les organites impliqués dans cette dernière voie sont des granules de sécrétion à cœur dense (GS), sui stockent les hormones ainsi que les glycoprotéines solubles, les granines. Parmi ces dernières, la chromogranine A (CgA) joue un rôle majeur dans la biogénèse des GS mais les mécanismes moléculaires ne sont pas clairement définis. Dans une lignée de cellules non-endocrines COS7 (dépourvues de granines et donc de voie de sécrétion régulée), mon équipe d’accueil a démontré que l’expression de la CgA induit la formation de vésicules présentant une structure et des fonctions caractéristiques des GS. L’analyse du protéome des GS purifiés à partir d’une lignée de cellules COS7 exprimant de manière stable la CgA (COS7-CgA) a révélé la présence de protéines liant les éléments du cytosquelette et le calcium. Durant ma thèse, nous avons focalisé notre attention sur la myosine 1b (myo1b), l’actine et le complexe de nucléation de l’actine Arp2/3 du fait de leur capacité à induire le bourgeonnement de compartiments post-golgiens dans des cellules non-endocrines. Nous avons montré (i) que la myo1b contrôle la formation des GS ainsi que la sécrétion régulée au sein des cellules COS7-CgA et des cellules neuroendocriniennes PC12, et (ii) que la myo1b et le complexe Arp2/3 permettent le recrutement d’actine fibrillaire dans la région golgienne et la formation des GS. Ces travaux montrent pour la première fois l’implication du complexe actomyosine dans la formation des GS. Afin d’identifier le lien moléculaire entre la CgA luminale et la myo1b cytosolique, nous avons recherché les interactions potentielles de la CgA avec les lipides de la membrane du réseau trans-golgien (TGN). Nous avons montré (i) que la CgA interagit avec l’acide phosphatidique (PA), (ii) que les espèces de PA prédominantes sont communes dans les membranes golgienne et granulaire, (iii) que la CgA est capable d’interagir spécifiquement avec des espèces de PA intégrées avec des membranes artificielles et (iv) que l’inhibition de la production du PA au niveau golgien altère significativement la formation des GS et la sécrétion régulée dans les cellules neuroendocrines. L’ensemble des résultats obtenus dans le cadre de ma thèse suggère que l’interaction entre la CgA et le PA est cruciale pour la biogenèse de GS à partir de la membrane du TGN. Nous émettons l’hypothèse que cette interaction est à l’origine de la formation de microdomaines enrichis en PA qui contrôleraient la courbure de la membrane du TGN et le recrutement du complexe actomyosineNeuroendocrine cells exhibit the constitutive secretory pathway which is common all cell types and allows the continuous renewal of the plasma membrane and the extracellular matrix, and the regulated secretory pathway, which is specific to secretory cells and allows hormone secretion following cell stimulation. The organelles supporting the latter pathway are dense-core secretory granules (SG), which store hormones and soluble glycoproteins, called granins. Among these, chromogranin A (CgA) plays a major role in the biogenesis of SG but the molecular mechanisms underlying this process are not clearly understood. Using non-endocrine COS7 cell line (which are devoid of granins and regulated secretory pathway), my host team has demonstrated that the CgA expression induces the formation of vesicles with structural and functional characteristic of SG. The proteome analysis of purified SG from a COS7 cell line stably expressing CgA (COS7-CgA) revealed the presence of cytoskeleton- and calcium-binding proteins. During my thesis, we focused our attention on myosin 1b (myo1b), actin and actin nucleation complex Arp2/3 due to their ability to induce the budding of post-Golgi compartments in non-endocrine cells. We have shown (i) that myo1b controls SG formation as welle as the regulated secretion in COS7-CgA and PC12 neuroendocrine cells, (ii) that myo1b and Arp2/3 complex are required to recruit fibrillar actin (F-actin) to the Golgi region and to SG formation. These results highlight for the first time the involvement of the actomyosin complex in SG formation. In order to identify the molecular link between luminal CgA and Cytosolic myo1b, we investigated the potential interactions of CgA with lipids of the trans-Golgi network (TGN) membrane. We showed (i) that CgA interacts with phosphatidic acid (PA), (ii) that the predominant PA species are common in Golgi and granular membranes, (iii) that Cg Ais able to interact specifically with these PA species included in artificial membranes, and (iv) that inhibition of PA production at the Golgi level significantly alters SG formation and regulated secretion in neuroendocrine cells. All these results obtained during my thesis suggest that the interaction between CgA and PA is crucial for SG biogenesis from the TGN membrane. We suggest that this interaction is at the origin of the formation of PA-enriched microdomains that could control the curvature of the TGN membrane and the recruitment of the actomyosin complex
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Gomes, Jessica Maria. "Molecular and structural analysis of complex lipids from Mycobacterium spp. and related inhibition studies." Thesis, University of Birmingham, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521949.
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Noack, Lise. "Rôle du complexe AtPI4Kalpha1 dans l’établissement de l’identité de la membrane plasmique et le développement chez Arabidopsis thaliana." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEN066.
Full textAbstract:
Les cellules sont composées de compartiments délimités par une membrane. Pour permettre aux protéines d’être associées aux membranes du bon compartiment, chaque membrane a une identité qui lui ait propre. Elle se définit par ses caractéristiques physiques et chimiques. Cependant, les compartiments d’une cellule échangent du matériel en permanence. Comment l’identité des membranes est maintenue malgré le flux constant d’échanges de protéines et de lipides lors des transports vésiculaires et non-vésiculaires ? Les phosphoinositides (PIPs) sont des lipides anioniques présents en faible quantité dans les membranes. Chaque PIP se localise différemment dans la cellule. Parmis les PIPs, le PI4P est présent à la membrane plasmique et au Golgi/trans-Golgi Network (TGN). Chez les plantes, PI4P est majoritairement trouvé à la membrane plasmique, contrairement aux animaux ou à la levure chez qui le PI4P se trouve principalement au niveau du TGN. Ainsi le gradient de PI4P le long de la voie d’endocytose est inversé chez les plantes par rapport aux autres eucaryotes. Chez les plantes, l’accumulation de PI4P à la membrane plasmique confère un champ électrostatique important qui recrute des protéines spécifiquement à cette membrane. Comment le gradient de PI4P est établi chez les plantes ? PI4Kα1 est capable de produire du PI4P à partir de phosphatidylinositol. PI4Kα1 se localise à la MP. Par ailleurs, PI4Kα1 est la sous-unité catalytique d’un complexe comprenant 3 autres protéines : NO POLLEN GERMINATION (NPG), EFR3 OF PLANTS (EFOP) et HYCCIN. Le complexe est ciblé à la membrane plasmique via une ancre lipidique au niveau de EFOP. Les orthologues de PI4Kα1 chez la levure et les animaux sont localisés à la membrane plasmique par des complexes protéiques similaires, démontrant une conservation des mécanismes de production des PIP chez l’ensemble des eucaryotes. L’absence du complexe PI4Kα1 entraine une létalité de la plantes au niveau du grain de pollen ou de l’embryon. Ainsi PI4Kα1 est essentiel à l’identité de la membrane plasmique et par conséquent au développement de la planteEukaryotic cells are composed of several membrane-surrounded compartments. Each compartment has a unique physicochemical environment delimited by a membrane with a specific biochemical and biophysical identity. The membrane identity includes the nature of the lipids, the curvature, the electrostaticity and the density of lipids at the membrane. The identity of each membrane allows the proper localization of membrane-associated proteins. Phosphoinositides are rare anionic lipids present in membranes. Five types of phosphoinositides exist in plants - PI3P, PI4P, PI5P, PI(4,5)P2 and PI(3,5)P2 - depending of the number and the position of phosphates around the inositol ring. They accumulate differently at the plasma membrane and in intracellular compartments and interact with proteins through stereo-specific or electrostatic interactions. Recent work uncovered that PI4P concentrates according to an inverted gradient by comparison to their yeast and animal counterpart. In plants, PI4P massively accumulates at the plasma membrane and is present in fewer amounts at the trans-Golgi Network (TGN). This PI4P accumulation at the cell surface drives the plasma membrane electrostatic field, which in turn recruits a host of signalling proteins to this compartment. Moreover the plant TGN is the place of vesicular secretion but is also involved in endocytic sorting and recycling, which might imply regulatory mechanisms of lipid exchanges or membrane identity maintenance between the plasma membrane and the TGN. Here, we characterized PI4Kα1 mutants and showed that pi4kα1 loss-of-function leads to pollen grain lethality and distortion in the allele transmission via the female gametophyte, while its knockdown displayed strong developmental phenotypes. Using yeast two hybrid screening and mass spectrometry, we identified that PI4Kα1 is part of an heterotetrameric complex composed of NO POLLEN GERMINATION (NPG), EFR3 OF PLANTS (EFOP) and HYCCIN (HYC). The interaction between PI4Kα1 and the structural subunits of the complex is essential to target PI4Kα1 at the plasma membrane. In addition, we showed that PI4Kα1 complex is anchored in immobile and predefined subdomains of the plasma membrane. This work opens new perspectives on the role of the PI4Kα1 complex in plasma membrane suborganization
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Ferreira, Vasconcelos Luis Daniel. "Oligonucleotide Complexes with Cell-Penetrating Peptides : Structure, Binding, Translocation and Flux in Lipid Membranes." Licentiate thesis, Stockholms universitet, Institutionen för neurokemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-109299.
Full textAbstract:
The ability of cell-penetrating peptides to cross plasma membranes has been explored for various applications, including the delivery of bioactive molecules to inhibit disease-causing cellular processes. The uptake mechanisms by which cell-penetrating peptides enter cells depend on the conditions, such as the cell line the concentration and the temperature. To be used as therapeutics, each novel cell-penetrating peptide needs to be fully characterized, including their physicochemical properties, their biological activity and their uptake mechanism. Our group has developed a series of highly performing, non-toxic cell-penetrating peptides, all derived from the original sequence of transportan 10. These analogs are called PepFects and NickFects and they are now a diverse family of N-terminally stearylated peptides. These peptides are known to form noncovalent, nano-sized complexes with diverse oligonucleotide cargoes. One bottleneck that limits the use of this technology for gene therapy applications is the efficient release of the internalized complexes from endosomal vesicles. The general purpose of this thesis is to reveal the mechanisms by which our in house designed peptides enter cells and allow the successful transport of biofunctional oligonucleotide cargo. To reach this goal, we used both biophysical and cell biology methods. We used spectroscopy methods, including fluorescence, circular dichroism and dynamic light scattering to reveal the physicochemical properties. Using confocal and transmission electron microscopy we observed and tracked the internalization and intracellular trafficking. Additionally we tested the biological activity in vitro and the cellular toxicity of the delivery systems. We conclude that the transport vectors involved in this study are efficient at perturbing lipid membranes, which correlates with their remarkable capacity to transport oligonucleotides into cells. The improved and distinct capacities to escape from endosomal vesicles can be the result of their different structures and hydrophobicity. These findings extend the knowledge of the variables that condition intracellular Cell-penetrating peptide mediated transport of nucleic acids, which ultimately translates into a small step towards successful non-viral gene therapy.
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Karkalas, John. "The use of enzymes for the quantitative analysis of starch and amylose-lipid complexes." Thesis, University of Strathclyde, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310894.
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Ferreira, Vasconcelos Luis Daniel. "Complexes of cell-penetrating peptides with oligonucleotides : Structure, binding and translocation in lipid membranes." Doctoral thesis, Stockholms universitet, Institutionen för neurokemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-141881.
Full textAbstract:
The fundamental element of life known to man is the gene. The information contained in genes regulates all cellular functions, in health and disease. The ability to selectively alter genes or their transcript intermediates with designed molecular tools, as synthetic oligonucleotides, represents a paradigm shift in human medicine. The full potential of oligonucleotide therapeutics is however dependent on the development of efficient delivery vectors, due to their intrinsic characteristics, as size, charge and low bioavailability. Cell-penetrating peptides are short sequences of amino acids that are capable of mediating the transport of most types of oligonucleotide therapeutics to the cell interior. It is the interaction of cell-penetrating peptides with oligonucleotides and the transport of their non-covalently formed complexes across the cellular membrane, that constitutes the main subject of this thesis. In Paper I we studied the effects of different types of oligonucleotide cargo in the capacity of cationic and amphipathic peptides to interact with lipid membranes. We found that indeed the cargo sequesters some of the peptide’s capacity to interact with membranes. In Paper II we revealed the simultaneous interaction of different molecular and supramolecular peptide and peptide/oligonucleotide species in equilibrium, with the cellular membrane. In Paper III we developed a series of peptides with improved affinity for oligonucleotide cargo as well as enhanced endosomal release and consequently better delivery capacity. In Paper IV we investigated the effect of saturated fatty acid modifications to a cationic cell-penetrating peptide. The varying amphipathicity of the peptide correlated with the complex physicochemical properties and with its delivery efficiency. This thesis contributes to the field with a set of characterized mechanisms and physicochemical properties for the components of the ternary system – cell-penetrating peptide, oligonucleotide and cell membrane – that should be considered for the future development of gene therapy.At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 2: Manuscript.
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Braun, Alain. "Synthese diastereoselective d'ethers lipides a visee antitumorale a l'aide de complexes dieniques du fer tricarbonyle." Université Louis Pasteur (Strasbourg) (1971-2008), 1996. http://www.theses.fr/1996STR13047.
Full textAbstract:
Dans le cadre d'une collaboration entre le cea et les laboratoires servier, nous nous sommes interesses a la synthese d'ethers lipides, analogues de structure rigidifiee du paf-acether. Au cours de ce travail, nous avons mis au point une nouvelle reaction d'heterocyclisation stereoselective de dienes diols complexes du fer tricarbonyle qui permet un acces direct a des 1,4-dioxanes 2,3-disubstitues fonctionnalises. Cette methode a ete appliquee a la synthese de differents 1,4-dioxanes, et a celle d'un ether lipide optiquement pur. La reactivite des differents diols complexes fer tricarbonyle au cours de l'heterocyclisation cationique a ete etudiee en fonction de la configuration relative, et de la nature de la chaine laterale de ces diols. Parallelement, la determination des configurations relatives des 1,4-dioxanes 2,3-disubstitues synthetises, nous a permis de proposer un mecanisme rationnel pour cette reaction d'heterocyclisation. Enfin, nous rapportons dans ce manuscrit quelques travaux preliminaires pour la synthese de 1,4-dioxanes tri- ou tetrasubstitues. Nous avons notamment etudie la reactivite de cations complexes fer tricarbonyle generes in situ, vis-a-vis de differents heteronucleophiles
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Orban, Tivadar. "Modeling the human prothrombinase complex components." Cleveland, Ohio : Cleveland State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=csu1210257089.
Full textAbstract:
Thesis (Ph.D.)--Cleveland State University, 2008.Abstract. Title from PDF t.p. (viewed on Oct. 8, 2008). Includes bibliographical references. Available online via the OhioLINK ETD Center. Also available in print.
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Brendel, Carole. "Etude des cofacteurs de récepteurs nucléaires impliqués dans la régulation du métabolisme lipidique." Université Louis Pasteur (Strasbourg) (1971-2008), 2001. http://www.theses.fr/2001STR13183.
Full textAbstract:
Les organismes répondent aux modifications de la quantité et de la composition des aliments qu'ils absorbent en modifiant l'expression de leur information génétique. Les récepteurs nucléaires impliqués dans le métabolisme lipidique sont des molécules clés qui permettent l'intégration de ces stimuli. Ils sont le plus souvent activés par des dérivés du cholestérol et des acides gras ainsi que par des acides biliaires. Les produits du métabolisme eux-mêmes sont ainsi capables de contrôler leur propre synthèse et leur devenir. Afin de moduler l'expression génique, les récepteurs nucléaires interagissent le plus souvent avec des cofacteurs qui remanient la structure de la chromatine par des modifications enzymatiques et/ou jouent le rôle de pont entre le récepteur et la machinerie transcriptionnelle de base. Ces cofacteurs peuvent activer (coactivateurs) ou réprimer (corépresseurs) la transcription. Un cofacteur donné peut interagir avec de multiples récepteurs nucléaires et un récepteur avec de multiples cofacteurs ; la détermination des conséquences physiologiques de ce partage est donc un des prochains enjeux de l'étude des cofacteurs. Ce travail de recherche a porté sur l'étude de deux cofacteurs de récepteurs nucléaires impliqués dans la régulation du métabolisme lipidique, le coactivateur MBF-1 et le corépresseur SHP. Tous deux sont capables d'interagir avec les récepteurs LRH-1, LXR et PPAR. La nature de l'interaction établie avec ces cofacteurs, l'effet de ces corégulateurs sur l'activité transcriptionnelle des récepteurs et leur mécanisme fonctionnel ont été analysés. Le MBF-1 permettrait le recrutement du complexe TFIID alors que le SHP interagirait avec l'ARN polymérase II. Ces nouvelles données s'avéreront sans doute très précieuses à l'avenir dans l'élaboration de thérapies innovantes pour le traitement de pathologies telles que l'athérosclérose, l'obésité, les dyslipidémies et le diabète non insulino-dépendantNuclear receptors implicated in the regulation of lipid metabolism establish a link between nutrition and gene expression. They are activated by cholesterol and fatty acids derivatives, as well as by bile acids. They interact with cofactors which can either activate (coactivators) or repress (corepressors) transcription. One cofactor can interact with several receptors and one receptor can interact with many cofactors. Two cofactors of nuclear receptors implicated in lipid metabolism have been studied, i. E. MBF-1, a coactivator, and SHP, a corepressor. Both of them are able to interact with receptors like LRH-1, LXR and PPAR. The type of interaction created between these cofactors and receptors, the influence of these coregulators on the transcriptional activity of the receptors, and their exact function have been assessed. MBF-1 might recrut the TFIID complex whereas SHP seems to interact with the RNA polymerase II. These new data should be helpful in the future for the elaboration of innovative therapies for treatment of pathologies such as atherosclerosis, obesity, dyslipidemia and non insulino-dependent diabetes