Дисертації з теми "Vésicule membranaire"
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Pansu, Robert. "Photochimie dans les membranes synthétiques de chlorure de di-octadecyl, di-méthyl ammonium (DODAC) : la vésicule de DODAC, mythe ou réalité ?" Paris 11, 1988. http://www.theses.fr/1988PA112122.
Повний текст джерелаCastagnos, Pauline. "Vésicules catanioniques : design et mécanismes de délivrance de principes actifs." Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1412/.
Повний текст джерелаSugar-derived catanionic surfactants self-assemble spontaneously into vesicles, which can encapsulate either hydrophilic drugs inside their aqueous core or hydrophobic and amphiphilic drugs inside their bilayer. Their biocompatibility, as well as their stability under time and dilution in biological media, allow to consider the use of these organized molecular systems for drug vectorization and delivery. In the present work, a mechanistic study showed these eco-designed and adjustable systems are able to fuse spontaneously with lipid assemblies mimicking cell membranes, provided that these latter present organization defects inside the bilayer. Cellular interaction mechanisms of such supramolecular systems were elucidated on cancer cell lines, by confocal microcopy and flow cytometry techniques. On the one hand, macropinocytosis, clathrin and caveolae pathways were shown to intervene as major active processes of cellular uptake of vesicles. The simultaneous intervention of these three pathways of endocytosis enables a progressive drug release through complementary mechanisms. On the other hand, experimental results verified that catanionic vesicles are capable of fusing with cell membranes. This spontaneous membrane fusion, concomitant with endocytosis, provides to these innovative systems the ability to deliver hydrophilic compounds directly inside cytoplasm. Numerous perspectives of such systems can thus be foreseen. An application towards vectorization of photosensible drugs was initiated in the present work, in order to fight cutaneous cancer through photodynamic therapy. These vectors, charged with hydrophobic active principles, showed enhanced stability and promising in vitro results for treatment of skin melanoma and oral squamous carcinoma
Silva, Rosa da Luz Brenda. "Caractérisation des vésicules extracellulaires dérivées de staphylococcus aureus et leur impact sur la réponse de l'hôte." Electronic Thesis or Diss., Rennes, Agrocampus Ouest, 2022. http://www.theses.fr/2022NSARB361.
Повний текст джерелаBacterial extracellular vesicles (EVs) are nanoparticles carrying macromolecules that can influence host-pathogen interactions. The pathogen Staphylococcus aureus (SA) releases EVs whose characteristics are still largely explored. This thesis’s project provides the first work extensively characterizing the RNA and protein content of profile of SA clinical HG003 strain and its producing cells. We found that EVs comprised all RNA classes including small regulatory RNA. The protein content of EVs was also diverse with various important elements such as virulence factors, transcriptional regulators, and metabolic enzymes. Interestingly, the protein and RNA content of EVs differed from that of its producing cells, suggesting that selective cargo packing exists. The intra- and interspecies role of EVs was also investigated.We found that the addition of HG003 EVs to bacterial cultures improved their growth in restrictive media. In the context of host-pathogen interactions, the cellular response induced by EVs differed from that induced by the living bacteria in both human and bovine models, indicating that EVs could display other physiological functions than those of bacteria which may be important to the infection process. Overall, our data evidence that SA EVs carry important newly discovered elements, and modulate the host response with different intensities, exposure periods, and by different routes from that of live bacteria. This study brings new knowledge about SA EVs potential functional roles in the context of bacterial physiology and staphylococcal infections
Kremer, Sébastien. "Extrusion de nanotubes membranaires : de la vésicule à la cellule vivante." Paris 6, 2009. http://www.theses.fr/2009PA066066.
Повний текст джерелаBorghi, Nicolas. "Nanotubes membranaires : extrusion hydrodynamique." Paris 6, 2006. http://www.theses.fr/2006PA066556.
Повний текст джерелаSolon, Jérôme. "Interactions entre membranes lipidiques chargées : instabilités, déformations et mouvement." Paris 6, 2004. http://www.theses.fr/2004PA066580.
Повний текст джерелаL'Heureux, Gaétan. "Utilisation de sondes fluorescentes dans la caractérisation des vésicules lipidiques : application au transfert d'énergie membranaire." Thèse, Université du Québec à Trois-Rivières, 1990. http://depot-e.uqtr.ca/6783/1/000583341.pdf.
Повний текст джерелаGaudin, Marie. "Etude des vésicules membranaires produites par les Archées hyperthermophiles marines de l'ordre des Thermococcales." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00716699.
Повний текст джерелаGaudin, Marie. "Etude des vésicules membranaires produites par les Archées hyperthermophiles marines de l’ordre des Thermococcales." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112093/document.
Повний текст джерелаSecretion of membrane vesicles (MVs) is an important physiological process that has been extensively studied in Bacteria and Eukarya. The recent discovery that Archaea produce MVs shows that this process is universal and suggests that the Last Universal Common Ancestor, LUCA, certainly produced MVs. As these archaeal MVs have been only studied in some Crenarchaeota (ex: G/ Sulfolobus), we started characterizing MVs produced by Thermococcales, a group of hyperthermophilic anaerobic Euryarchaeota.In the first part of this study we examined the mechanism of production as well as the protein and lipid composition of MVs produced by three strains of Thermococcales: Thermococcus kodakaraensis, Thermococcus gammatolerans and Thermocococus sp. 5-4. We observed that MVs are released by a budding process from the cell envelope that is similar to ectosome formation in eukaryotic cells. Moreover, clusters of MVs often form filamentous structures and protuberances on cell surfaces, resembling recently described bacterial nanopods. Differences in structure are observable between MVs of the three species, as well as in their protein composition. However, MVs and cell membranes from the same species have a quite similar protein and lipid composition, confirming that MVs are produced from cell membranes. A major protein present in cell membranes and MVs from the three strains is the oligopeptide-binding proteins (OppA), which has homologues in MVs from Sulfolobus species. Thermococcales MVs harbor DNA and protect this DNA against thermodegradation. Here, we show that T. kodakaraensis cells transformed with the shuttle plasmid pLC70 release MVs harboring this plasmid. Interestingly, these MVs can be used to transfer pLC70 into plasmid-free cells, suggesting that MVs could be involved in DNA transfer between cells at high temperature. In the second part of this study, we were specially interested in the strain Thermococcus nautilus, a Thermococcale that produces MVs selectively enriched in two plasmids from the cell. Notably, one of them corresponds to the genome of a defective virus from PRD1-adenovirus lineage. This indicates that MVs can be used as vehicles for the transport of viral genomes and suggests that production of MVs by ancestral cells could have played a role in the origin of viruses.In addition to be involved in transport of plasmids/viruses, MVs from T. nautilus display a toxic effect on some strains of Thermococcales, maybe due to the delivery of toxins. Even if these “thermococcins” remain to be characterized, this is the first time that a toxic activity associated with MVs has been shown in Thermococcales
Dilda, Pierre. "Caractérisation de CFTR dans des vésicules membranaires purifiées a partir d'épithélium de trachée bovine : approche pharmacologique." Paris 5, 1995. http://www.theses.fr/1994PA05CD08.
Повний текст джерелаDa, Costa Grégory. "RMN des petites vésicules unilamellaires lipidiques (SUV) : une approche adaptée à l'étude des interactions périphériques membranaires." Rennes 1, 2007. http://www.theses.fr/2007REN1B106.
Повний текст джерелаSUV (Small Unilamellar Vesicles) are constituted of one lipidic bilayer. They have beeb so far only poorly used as model membrane for proton NMR studeis. Based on this work, on porphyrins, free of metallated, diamagnetic of paramgnetic, we show that the kinetic dissociation rate constant is able to cancel the anisotropic interactions, thus allowing the recording of sharp signal even for the molecule bound to the SUV. Using various sterol derivatives, we demonstrated the intinsic mobility of incorporated molecules is able to induce a good averaging of anisotropic interaction. Overall, these results have permit to rationalize the required conditions for recording NMR spectra of drugs, peptides in interaction with SUV
Martin, Solenne. "La P-glycoprotéine : analyse des différents sites de liaison de ses substrats et de sa fonction de transport." Paris 11, 2006. http://www.theses.fr/2006PA112106.
Повний текст джерелаCoste, Virginie. "Formation de domaines de type "rafts" dans des vésicules unilamellaires et mécanismes physico-chimiques de l'extraction de domaines membranaires." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2006. http://tel.archives-ouvertes.fr/tel-00116250.
Повний текст джерелаCoste, Virginie. "Formation de domaines de types "rafts" dans des vésicules unilamellaires et mécanismes physico-chimiques de l'extraction de domaines membranaires." Paris 6, 2006. https://tel.archives-ouvertes.fr/tel-00116250.
Повний текст джерелаIn this work, we have been interesting in the study of the liquid-ordered/liquid-disordered (lo/ld) phase coexistence within LUV (Large Unilamellar Vesicle) membranes model. First, we have attempted to develop a methodology both allowing the detection of lo phase formation and the quantitative estimation of membrane fraction Φo occupied by lo phase in LUV of ternary composition: PC/SM/Chol (phosphatidylcholine /sphingomyeline /cholesterol). For this purpose, the properties of fluorescence self-quenching and selective partitioning between lipid phases of a unique fluorescent probe (C12NBD-PC) were used. The second part of our work has been dedicated to the study of the solubilization of LUVs showing lo/ld phase coexistence by Triton X-100 detergent. Our aim was to demonstrate the possibility to extract strictly lo phase membrane fraction, by the study of structural transitions induced by Triton X-100 interactions with LUVs at 4°C
Perbet, Romain. "Rôle des vésicules extracellulaires dans la propagation de la protéine Tau." Thesis, Lille 2, 2020. http://www.theses.fr/2020LIL2S023.
Повний текст джерелаIntra-neuronal accumulation of tau protein aggregates is one of the common feature of a group of heterogeneous neurodegenerative diseases called tauopathies. In some of them, the pathology will first affect a region before spreading to other regions.This staging could be linked to the prion-like propagation of pathological seed-competent tau species. These seeds, identified in transgenic mice interstitial fluid (ISF) and in human cerebrospinal fluid (CSF) are uptaken by cells and induce subsequent intracellular tau aggregation (Takeda et al., 2016). The pathological species of tau which are spreading are not yet well characterized but several mechanisms mediating their transfer (secretion and capture) have been highlighted. Among them, we demonstrated that tau is secreted in extracellular vesicles (EV´s) (Dujardin et al., 2014). We also know that neurons are implicated in this transfer but the role of glial cells is unknown.In this context, we wanted to: 1 / demonstrate that pathological Tau protein is present in EVs extracted from brain of patients suffering from different Tauopathy and that those EVS induce pathology in animals. 2 / detect pathological Tau species in EVs extracted from plasma and CSF, potential biomarkers of Tauopathies. 3 / demonstrate that Tau protein can be transferred from neuron to astrocyte and, if so, to determine the transfer pathway.To test the seeding potential of EV’s containing in ISF derived from human brain of patient presenting tauopathies, and Tau 30 mouse brain we have used a sensitive and specific tau biosensor assay. Our results demonstrate that EVs isolated from ISF of AD patient, PSP patient and Tau 30 mouse contain seed prion-like properties. The ability of these seeds to recruit tau seems to be correlated to the severity of tau pathology (prefrontal>occipital>cerebellum) for AD. This might reflect the slight presence of neurofibrillary degeneration as well as extracellular tau in this pathology in comparison to AD. Finally, the presence of seeds-containing EV’s in the extracellular space supports the idea that these shuttles might be implied in the prion-like propagation of tau pathology in Humans. Additionally, tau pathology spreading is driven by EV’s rather than by free-floating tau species.We also demonstrated that tau can be transferred from neuron to astrocyte; this transfer is more efficient with EV’s than with free floating tau.These data open new avenues for therapeutic interventions that might targets the toxic and propagative species
Huang, Xiao Hang. "Etude du trafic membranaire chez les algues marines : les vesicules mantelees de laminaria digitata et ulva lactuca." Paris 5, 1988. http://www.theses.fr/1988PA05S006.
Повний текст джерелаGerbeaud, Claire. "Effet de l'insertion de protéines et de peptides membranaires sur les propriétés mécaniques et les changements morphologiques de vésicules géantes." Bordeaux 1, 1998. http://www.theses.fr/1998BOR10649.
Повний текст джерелаDe, rezende rodovalho Vinicius. "Caractérisation du contenu protéomique et des propriétés immunomodulatrices des vésicules extracellulaires secrétées par la bactérie probiotique Propionibacterium freudenreichii CIRM-BIA129." Thesis, Rennes, Agrocampus Ouest, 2021. http://www.theses.fr/2021NSARI082.
Повний текст джерелаExtracellular vesicles (EVs) are spherical nanoparticles involved in the intercellular exchange of molecules, such as proteins. Several organisms produce EVs, including probiotic bacteria. Propionibacterium freudenreichii is a Gram-positive bacterium that emerged as a probiotic due to notable beneficial properties, including immunomodulation. Some of these properties have been attributed to factors exposed on the surface or secreted by the bacterium. Therefore, we investigated wether P. freudenreichii produced EVs that could mediate its beneficial properties. The bacteria were cultured in milk ultrafiltrate or yeast extract-lactate medium,and the concentrated culture supernatants were then purified by size exclusion chromatography or density gradient ultracentrifugation. Spherical nanoparticles were obtained, confirming the production of EVs by the bacterium. Analysis of the EVs protein content and interactomics indicated potential immunomodulatory roles, which was confirmed by cell culture assays measuring IL-8 release and NF-KB activity. Additionally, the properties and activity of EVs varied depending on the culture medium and the purification method. Overall, these results contribute to the understanding of the mechanisms of the probiotic effect in P. freudenreichii and show the potential for the development of novel nanotechnological delivery systems, with a potentially significant impact on human health
Sauvage, Sophie. "Structures membranaires à base de tensioactifs fluorés non ioniques : phases aqueuse et émulsions-gels concentrées." Nancy 1, 1993. http://www.theses.fr/1993NAN10374.
Повний текст джерелаHabib, Lamice. "Étude des propriétés membranaires des vésicules lipidiques incorporant des triterpènes oxygénés bioactifs d'origine végétale : application à la cucurbitacine E et à l'érythrodiol." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10022/document.
Повний текст джерелаCucurbitacin E and erythrodiol are natural oxygenated triterpenes having respectively, a tetra and pentacyclic skeleton. They are known for their numerous biological properties. In this thesis, we studied their interaction with the membranes of lipid vesicles to better understand their pharmacodynamics. We have prepared liposomes in the absence and presence of cucurbitacin E and erythrodiol using the reverse phase evaporation technique followed by extrusion, the hydration of lipid film and the ethanol injection techniques. The physicochemical characteristics of lipid vesicles incorporating or not the triterpenic molecules were investigated by appropriate techniques. The determination of cucurbitacin E and erythrodiol in the vesicles by high performance liquid chromatography showed high incorporation efficiencies of both triterpenes. Size measurements obtained by dynamic light scattering showed that liposomes incorporating triterpenes were smaller than empty liposomes. The images obtained by transmission electron microscopy confirmed the formation of spherical vesicles. Measurements of vesicles dimensions by atomic force microscopy (AFM) demonstrated that liposomes incorporating cucurbitacin E were higher and more resistant to the force exerted by the AFM tip than the blank liposomes. Liposomes incorporating erythrodiol were more fragile and tend to break up into lipid bilayers on the mica surface. Results obtained by differential scanning calorimetry suggested that cucurbitacin E is localized at the polar-apolar interface of the liposomal membrane while erythrodiol is inserted between the acyl chains of the phospholipids leading to the formation of heterogeneous lipid domains. The release kinetics of the sulforhodamin B encapsulated into the aqueous phase and measured by fluorescence spectroscopy revealed that the liposomal membrane becomes in the presence of cucurbitacin E, more permeable to this probe. The overall results suggest that cucurbitacin E and erythrodiol affect differently
Mauroy, Chloé. "Fusion d'auto-assemblages lipidiques." Toulouse 3, 2010. http://thesesups.ups-tlse.fr/1039/.
Повний текст джерелаMembrane fusion processes play a key role in biological system. Fusion processes involve destabilization of membrane organization. This is a controlled phenomenon which is not spontaneous because of energetic barriers. To abolish these barriers, it is necessary to provide energy to the system. In a first part, electrofusion between two giant unilamellar vesicles (GUVs) was studied. The fusogenic state was obtained by the application of an exogenous electric field to induce membrane electropermeabilization. External electric field can induce membrane destabilization allowing fusion between these two membrane systems in contact during the electric pulse. We characterized, on the first hand, the role of phase states of the membrane and the critical electric field for electropermeabilization and, on the other hand, the morphological modifications associated to this homofusion. In a second part, spontaneous fusion between catanionic vesicles and GUVs with different compositions and phase states was studied. We underline the fact that the interactions between these two systems depend, on the first hand, on the phase states of the GUVs and, on the other hand, on the electrostatic interactions between them. Fusion is induced when the membrane is destabilized. This destabilization is induced here by the presence of an endogenous electric field revealed by the zeta potential of the catanionic vesicles
Perrot, Nahuel. "Production dans Escherichia coli de vésicules enrichies en cavéoline-1(32-178) canine ou son fragment (76-178)." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS067.
Повний текст джерелаCaveolin-1, a 21 kDa membrane protein, is the principal membrane protein ofcytoplasmic membrane domains named caveolae. Specifically enriched incholesterol and sphingolipids those domains are important in many aspect of the cell's life and make up a proteins and lipids interaction platform. In the past years, despite a large number of publications stating the implication of caveolin-1 or caveolae in many cell processes and pathologies, very few is known about theway this protein is organized at the cell membrane. Hence, the main purpose of thiswork is to contribute to the acquisition of structural data on this protein. At the base of this work is the heterologous expression within a bacterial host, and as a fusion protein, of the canin beta isoform of cavéolin-1 or one of its fragment. These expressions lead to the formation of cytoplasmic vesicles composed mainly ofthe expressed protein. Thence, the first part of this work focus on developping a method to purify those vesicles that does not rely on using any kind of detergent which could enable structural studies in a native environnment. The second part present a potentiel application of those vesicles and inparticular the use of those vesicles to characterize a membrane enzyme, namelythe murin microsomal glutathion-Stransferase. The last part will be a contribution to data analysis within the context of molecular dynamics simulationof membraneous systems
Ruffiot, Pauline. "Développement de systèmes membranaires modèles pour la vacuole parasitophore de Toxoplasma gondii : intéractions des protéines de granules denses (protéines GRA) avec des vésicules unilamellaires." Phd thesis, Grenoble 1, 2007. http://www.theses.fr/2007GRE10104.
Повний текст джерелаGRA proteins are secreted by the intracellular parasite Toxoplasma gondii into the parasitophorous vacuole, where most of them interact with two systems of tubular membranes: the Host Organelle Sequestering Tubules (HaSTs) and the Membrane Nanotubules Network (RNM). Although most of the GRA proteins contain potential transmembrane domains, they are secreted as soluble forms and become membrane-associated only when they reach their target membranes. This unusual property led to consider them as attractive models of protein-membrane interactions. 1 developed two experimental approaches to study the interactions of GRA proteins, extracted trom the parasite or trom the vacuole, with model membranes. Firstly, biochemical approaches using Small Unilamellar Vesic1es (SUVs) led to characterize the solubilisation forms of GRA proteins and their association with SUVs membranes. Secondly, 1 developed a Giant Unilamellar Vesic1es (GUVs) model to study the interactions of GRA proteins with membranes by fluorescence spectroscopy methods. The results provide elements 1) which help to decipher the traffic of GRA proteins within the parasite and the PV, and 2) which open the way to set up an in vitro minimal system to study the building up of the parasitophorous vacuole and of its associated tubular membranes
Fagla-Amoussou, Akouavi Balbine. "Etude des interactions polluants aromatiques polycycliques (HAP)-récepteurs adrénergiques-phospholipides membranaires dans le tissu adipeux." Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL080N/document.
Повний текст джерелаObesity is a disease defined by an accumulation of fat in adipose tissue with adverse consequences for health. The causes of obesity are many.In recent work, there was demonstrated the role of environmental pollution in weight gain.In this work, the assumptions that the adrenergic receptors on the surface of fat cells would home to the accumulation of polycyclic aromatic pollutants have been verified by measurement of several agonists and antagonists specific and non-specific in the presence or absence of benzo[a]pyrene receptors on human cells and Chinese hamster (CHO). The amounts of cAMP obtained showed that PAHs are not deposited on β-receptors, β1, β2, β3 adrenergic receptors.This accumulation occurs at the cytoplasmic membrane phospholipids of the cells. What cau-ses stiffness of the membranes. This observation tends to reinforce the hypothesis that benzo [a]pyrene induce an inhibition of lipolysis by the accumulation in the phospholipid bilayer and conformational changes of the bilayer phospholipids in the vicinity of receptors seven transmembrane domains which are β-adrenergic receptors
Marconi, Séverine. "Dosage de l'activité endoprotéolytique de neurotoxines clostridiales." Aix-Marseille 2, 2008. http://www.theses.fr/2008AIX20690.
Повний текст джерелаNeurotransmitter-filled synaptic vesicles fuse in a calcium-dependent manner with the plasma membrane to release their content into the synaptic cleft. VAMP2, a synaptic vesicle membrane protein, interacts with SNAP-25 and syntaxin1 localized on the plasma membrane. These proteins, called SNAREs, assemble into a heterotrimeric complex that brings the vesicle and the plasma membranes into close apposition. Botulinum neurotoxins (BoNTs), the most toxic biological substances known, inhibit synaptic neurotransmission by cleaving SNAREs. There are seven BoNT serotypes named A to G of which BoNT/ B and F cleave VAMP2 and BoNT/A and E cleave SNAP-25. The increasing use of BoNTs as therapeutic and cosmetic agents, but also the threat they constitute as potential bioweapons, highlight the need for development of in vitro assays to detect their endoproteolytic activity. These alternative methods should replace the mouse bioassay which is the current reference method. An in vitro assay for the detection of the catalytic activity of BoNT/B and F has been developed by Ferracci et al. In 2005. It is based on the direct quantification of synaptic vesicle proteins, in particular VAMP2, by their immuno-capture on specific antibodies immobilized on the sensor chip surface. For BoNT/B, this test was shown to be 200 times more sensitive and up to 25 times faster than the reference in vivo toxicity test in mice. Using synaptic vesicles as a substrate, a comparison of the EC50s for BoNT/B obtained by SPR, ELISA or flow cytometry indicated similar sensitivity although SPR assays were more rapid and economical. We also showed that synaptic vesicles are a robust substrate, that can be lyophilized, allowing the detection of BoNT/B activity in complex media. With an immunoisolation step of BoNT/B from serum, the assay was shown to be 30 times more sensitive than the mouse bioassay. We developed an SPR-based method allowing the quantification of plasma membrane proteins and the detection of BoNT/A activity. Sonication of brain or neuronal cultures generated plasma membrane fragments with accessible intra-cellular epitopes adapted to analysis by SPR. SPR responses were proportional to antigen concentration permitting detection of as little as 4 pM SNAP-25 in crude lysates. BoNT/A activity was assayed using monoclonal antibodies that specifically recognize a SNAP-25 epitope generated by the proteolytic action of the toxin. The SPR biosensor method was sensitive enough to monitor BoNT/A and B activity in cells cultured in a 96-well format and could favourably replace time-consuming techniques for the measurement of toxin activity
Salim, Cláudio. "Expression de la protéine géante AHNAK après lésion de la moelle épinière et dans le système nerveux périphérique : études fonctionnelles sur les cellules de Schwann in vitro." Paris 6, 2007. http://www.theses.fr/2007PA066507.
Повний текст джерелаAhnak gene in rat has been first identified by a differential screening that aimed in identifying proteins overexpressed in a spinal cord injury. After a spinal injury in rat, AHNAK is expressed by different types of cells invading the lesion epicenter as soon as 48h after injury. Those cells constitute the fibrotic component of the glial scar, and produce ahank at least until 6 months after injury. AHNAK expressing cells delineate the inner border of cystic cavities in the lesion epicenter, suggesting that AHNAK may participate in the formation of a tissue-protective barrier. In the peripheral nervous system, AHNAK is constitutively expressed by sensory neurons of the dorsal root ganglia, satellite cells, and Schwann cells from the nerve. During myelination in rat, AHNAK is redistributed from a strictly perimyelinic compartment of the external cytoplasm, to a more diffuse distribution associated with the outer surface of vesicles, and with the abaxonal plasma membrane. In non confluent Schwann cells in vitro, AHNAK and the laminin-receptor dystroglycan are associated with filopodia-like cell extensions. Ahnak interference in Schwann cells induces retraction of cell processes and detachment from laminin coated surfaces, associated with a reduction of the Schwann cell content in beta-dystroglycan and a nuclear translocation of Schwann cell specific dystrophin Dp116 which normally binds beta dystroglycan with the actin cytoskeleton. . We suggest AHNAK to be implicated in targeting and/or scaffolding of the dystroglycan-associated complex to the abaxonal membrane. Thus, similarly to periaxin with which it shares certain features, AHNAK may contribute to SC-basal lamina interaction, and myelin formation and/or maintenance
Boom, Alain. "Etude de la perméabilité hydrique de l'épithélium vésical de "Bufo marinus" sensible à l'hormone antidiurétique: rôle des protéines G et de la perméabilité membranaire à l'adénosine monophosphate cyclique (cAMP)." Doctoral thesis, Universite Libre de Bruxelles, 2001. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211527.
Повний текст джерелаRousseau, France. "Régulation pré-synaptique de la transmission inhibitrice par le transporteur neuronal de la glycine (GlyT2)." Paris 6, 2008. http://www.theses.fr/2008PA066239.
Повний текст джерелаAllain, Jean-Marc. "Instabilités des membranes lipidiques inhomogènes : implications biologiques." Phd thesis, Université Paris-Diderot - Paris VII, 2005. http://tel.archives-ouvertes.fr/tel-00011333.
Повний текст джерелаpetite taille, appelées 'rafts', existeraient dans les membranes cellulaires. Différentes expériences sur des vésicules multiphasiques montrent que cette inhomogénéïté latérale favorise des instabilités de forme. Nous avons modélisé trois instabilités différentes, observées expérimentalement, pour mieux comprendre comment les propriétés mécaniques des vésicules sont affectées par l'existence d'un domaine. Deux instabilités concernent des déformations hors du plan de la bicouche : la rupture d'un tube de membrane, provoquée par les contraintes mécaniques internes, et l'éjection d'un domaine d'une vésicule tendue, soit par l'absorption de molécules soit par un changement de pression osmotique. Enfin, nous avons modélisé une instabilité illustrant le comportement hydrodynamique de la bicouche, qui justifie le concept de viscosité associé à celle-ci tout en soulignant son caractère bidimensionnel.
Payet, Laurie-Anne. "Effets des acides gras saturés sur la voie de sécrétion. Relation avec la mucoviscidose." Thesis, Poitiers, 2013. http://www.theses.fr/2013POIT2299/document.
Повний текст джерелаSaturated fatty acids (SFA) have been reported to alter organelle integrity in many cell types. This process, also known as lipotoxicity, has been proposed to be responsible for several human pathologies such as type 2 diabetes.At the cellular level, SFA accumulation is associated with an increase of the saturation rate of membrane phospholipids (PL), the major components of organelle membranes, and an increase of ceramides levels, implicated in apoptosis induction.In the first part of this work, we took advantage of a simple yeast-based model to study the relative contributions of saturated PL and ceramides to SFA cytotoxicity. We demonstrated that ceramides act early in the secretory pathway, while saturated PL impact the later steps, and particularly the formation of secretory vesicles.In parallel, we observed that SFA amounts were significantly increased in the membrane PL of cystic fibrosis (CF) patient cells. The most common mutation responsible for this genetic disease results in the retention of the corresponding protein in the endoplasmic reticulum. Pharmacological agents, which correct the mistrafficking of the protein, have been isolated in vitro, but they did not show significant improvements in clinical trials. We propose in the present manuscript, that SFA-related lipointoxication could be an important bottleneck for the use of these pharmacological agents in clinical trials
Liu, Yi. "Calcium-related fungal genes implicated in arbuscular mycorrhiza." Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00985826.
Повний текст джерелаBeillevaire, Déborah. "Rôle de l’autophagie dans la biogenèse des vésicules membranaires apoptotiques." Thèse, 2019. http://hdl.handle.net/1866/23509.
Повний текст джерелаIschemia/reperfusion (I/R) occurring in all solid organ transplantation, constitute a proautophagic / pro-apoptotic stimulus on endothelial cells. We recently demonstrated that apoptotic endothelial cells (CEapo) secrete apoptotic exosome-like vesicles (ApoExo) that induce autoimmune response and accelerate vascular rejection in a mouse aortic transplant model. These ApoExo, that differ from classical apoptotic bodies in structure and protein content, contain the C-terminal fragment of perlecan, LG3. LG3, an autoantigen of importance in transplantation, promotes vascular remodeling and is increased in circulation in renal transplant patients undergoing vascular rejection. In addition, the presence of anti-LG3 antibodies prior to transplantation is associated with a higher risk of developing vascular rejection in kidney transplant patients and long-term graft loss. It is known that the generation of LG3 fragment involves the proteolysis of perlecan by cathepsin-L, a lysosomal protease, but the mechanism of export of this fragment within ApoExo is still unknown. We hypothesized that lysosomal activity and autophagy play an important role in the maturation and the secretion of LG3 in ApoExo vesicles secreted by CEapo. Longitudinal electron microscopy study after 1h, 2h and 3h in serum starved endothelial human cells revealed the presence of perlecan / LG3 fragment within autophagic compartments (autophagosomes and autophagolysosomes) at different stages of the autophagic process. After 3 hours of serum starvation, we identified LG3 fragment in membrane vesicles located within large vacuolar networks reminiscent of autophagolysosomes. Inhibition of cathepsin-L, of lysosomal acidification and of autophagy decrease the presence of LG3 fragment in ApoExo vesicles without affecting vesicle secretion thus demonstrating the role of autophagy in the secretion of LG3 fragment within ApoExo. However, Injection of ApoExo LG3- vesicles from bafilomycin-treated aortic murine cells into a murine aortic transplant model induces autoimmune anti-LG3 response and vascular remodeling at levels similar to the ApoExo vehicle mice control group. Proteomic analysis of ApoExo from bafilomycin-treated aortic murine cells has demonstrated that bafilomycin modifies ApoExo protein content by inducing an increase of the presence of lysosomal proteins and the extracellular matrix, including perlecan. This suggests that the presence of LG3 motif in uncleaved native perlecan in ApoExo LG3- could be responsible for the establishment of the anti-LG3 response as well as the vascular remodeling observed in mice. Collectively, these results demonstrate that autophagy in endothelial cells producing ApoExo does not regulate the immuogenicity of ApoExo. However, it regulates within apoptotic endothelial cells the processing and cleavage of perlecan who is immunogenic. Indeed, autophagy modulates the different forms of native and cleaved perlecan secreted in ApoExo. Grafted mice study thus allowed us to consider neither the involvement of the LG3 fragment but the implication of the LG3 motif present in the uncleaved native perlecan and its intermediate forms in the anti-LG3 autoimmune response and vascular rejection. Modulating perlecan and LG3 secretion in ApoExo vesicles is a potential therapeutic target to reduce the autoimmune response that can increase vascular damage after transplantation.
Schmidt, Maxime. "Développement d’une méthode de production de vésicules membranaires permettant l’étude du mode d’action des toxines insecticides de Bacillus thuringiensis." Thèse, 2016. http://hdl.handle.net/1866/19119.
Повний текст джерелаMost Bacillus thuringiensis toxins permeabilize the intestinal membrane of susceptible insects by forming pores that abolish transmembrane electrical potentials and ionic gradients. Several toxins have been studied using brush border membrane vesicles purified from the insect midgut. Unfortunately, the intestinal membrane from many insects does not form vesicles that are tight enough to be used in permeabilisation experiments. A new technique using giant liposomes and a membrane permeability probe was developed to evaluate the pore-forming ability of two particularly promising toxins for the biocontrol of a major corn pest, the Western corn rootworm (Diabrotica virgifera virgifera LeConte), Cry6Aa1 and the binary toxin DS10/DS11. Both toxins permeabilized the liposomes efficiently. However, analysis of the permeabilisation rates under different experimental conditions indicates that these toxins differ in their biophysical properties. The binary toxin forms pores which are slightly selective for cations, like most B. thuringiensis toxins. On the other hand, although the results suggest that Cry6Aa1 could form anion-selective pores, they could also indicate that, in contrast with other toxins produced by this bacterium, it could form pores only under high ionic strength conditions. Pore formation by both toxins appears to be sensitive to membrane curvature since it is much more efficient in giant liposomes than in liposomes with identical composition, but smaller in size. This study sets the bases for the development of a technique that would allow the toxins to be studied in giant liposomes enriched with proteins and lipids from the intestinal membrane of target insects.
Kirouac, Martin. "Effets des toxines insecticides du Bacille de Thuringe sur la perméabilité des vésicules de membrane à bordure en brosse intestinale du sphinx du tabac." Thesis, 2006. http://hdl.handle.net/1866/17385.
Повний текст джерелаRuffiot, Pauline. "Développement de systèmes membranaires modèles pour la vacuole parasitophore de Toxoplasma gondii :Interactions des protéines de granules denses (protéines GRA) avec des vésicules unilamellaires." Phd thesis, 2007. http://tel.archives-ouvertes.fr/tel-00177965.
Повний текст джерелаAouameur, Rym. "Caractérisation du co-transporteur Na+/myo-inositol SMIT2 dans les membranes en bordure en brosse de rein de lapin et d’intestin de rat." Thèse, 2009. http://hdl.handle.net/1866/2846.
Повний текст джерелаMyo-inositol (MI) is an organic solute involved in various aspects of cell physiology, including cell signaling. It is also known as a compatible osmolyte. Three secondary active MI cotransporters have been identified; two are Na+- coupled (SMIT1 and SMIT2) and one is H+-coupled (HMIT). The main aim of this study was to characterize MI uptake throught SMIT2 as expressed in epithelial cells and in Xenopus laevis oocytes. In order to achieve the characterization of this transport system, we used purified brush border membrane vesicles (BBMv) isolated from rabbit kidney and rat intestine. We first performed a quantification of mRNA levels in rabbit kidney using real time PCR for both SMIT1 and SMIT2. We found that SMIT1 is mainly expressed in the renal medulla while SMIT2 is mainly localized in the renal cortex. This result was confirmed on Western blots using an antibody raised against SMIT2. Through inhibition studies using selective substrates for SMIT1 (inhibited by L-fucose) and SMIT2 (inhibited by D-chiroinositol), we showed that SMIT2 seems to be responsible for all the apical transport of MI into the proximal convoluted tubule with a Km of 57 ± 14 µM. By transport studies we established that rabbit intestine seems to lack apical transport of MI while rat intestine has a very active uptake of this molecule. qRT-PCR quantification confirmed the absence of MI transporters in rabbit intestine. As for kidney, SMIT2 seems to be the only transporter responsible for apical MI uptake in enterocytes with a Km of 150 ± 40 µM. Functional analysis of rat SMIT2 activity, via electrophysiological studies in Xenopus oocytes, demonstrated similarities to the activities of SMIT2 from rat intestine and rabbit kidney. SMIT2 displays high affinities for MI (270 ± 19 µM), DCI (310 ± 60 µM) and no affinity for L-fucose. SMIT2 is very sensitive to phlorizin (Pz; 16 ± 7 µM). Although these functional characteristics essentially confirmed those found in rat intestine, a iv discrepancy exists between the two systems studied. Indeed, the affinity constant for glucose was approximately 40-fold lower in vesicles than in oocytes. We also tested the ability of SGLT1 and GLUT5, other sugar transport systems present in enterocytes apical membranes, to perform MI uptake. Because the inhibition of these transporters did not alter radiolabeled MI uptake, we concluded that they had no significant contribution to MI transport in rat intestine. Finally, the basolateral efflux of MI was not mediated by GLUT2 because when expressed in oocytes, this transporter was not able to transport MI.