Дисертації з теми "Intracellular vacuoles"
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Kern, Beate. "Analysis of Helicobacter pylori VacA-containing vacuoles and VacA intracellular trafficking." Diss., Ludwig-Maximilians-Universität München, 2015. http://nbn-resolving.de/urn:nbn:de:bvb:19-184058.
Повний текст джерелаKortebi, Mounia. "Caractérisation d’une phase de persistance intracellulaire du pathogène Listeria monocytogenes." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS477/document.
Повний текст джерелаListeria monocytogenes is a facultative intracellular pathogenic bacterium responsible for a serious disease, listeriosis. Although much work has been done to characterize the virulence mechanisms of this bacterium, there is little data on the mechanisms leading to the asymptomatic carriage of L. monocytogenes in mammalian hosts. One of these mechanisms could be a phase of intracellular persistence. During prolonged infections of human epithelial cells in culture, such as hepatocytes and trophoblast cells, L. monocytogenes changes its intracellular lifestyle. After the active phase of cell-to-cell spread, the bacteria stop polymerizing actin and become trapped in single-membrane vacuoles labeled with the endosomal protein LAMP1.The aim of my thesis was to characterize these "Listeria-Containing Vacuoles" (LisCVs). We have shown that LisCVs are acidic, partially degradative compartments, labeled by the lysosomal protease cathepsin D. Their formation coincides with the disappearance of actin polymerization factor ActA from the bacterial surface and the capture of actin-free cytosolic bacteria by cell membranes. In these compartments, bacterial growth is slowed; a subpopulation is resistant to stress and can survive beyond three days of infection. The use of gentamicin during the infection protocol is not responsible for the formation of LisCVs. However, this antibiotic allows selection of vacuolar bacteria, by specifically inhibiting the growth of cytosolic bacteria. The formation of LisCVs is not specific to laboratory strains. However, the efficacy of the phenomenon could diverge according to the sequence types of L. monocytogenes strains. Vacuolar bacteria have the ability to exit the vacuoles and return to a motile and replicative state during the subculture of infected cells. When expression of the actA gene remains inactive, as in ΔactA mutants, vacuolar Listeria forms persist in host cells in a viable but non-culturable (VBNC) state. These VBNC forms can be transmitted during host cell divisions. All these results reveal a new phase of persistence in the intracellular infectious process of L. monocytogenes during prolonged infections of a subset of epithelial cells. This property could contribute to asymptomatic carriage of this pathogen in epithelial tissues, extend the incubation period of listeriosis, and make bacteria tolerant to antibiotic therapy
Kern, Beate [Verfasser], and Rainer [Akademischer Betreuer] Haas. "Analysis of Helicobacter pylori VacA-containing vacuoles and VacA intracellular trafficking / Beate Kern. Betreuer: Rainer Haas." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2015. http://d-nb.info/1074825454/34.
Повний текст джерелаPereira, Camila Serva. "Aderência, invasão e persistência intracelular de estreptococos do grupo B em células epiteliais respiratórias A549." Universidade do Estado do Rio de Janeiro, 2010. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=2392.
Повний текст джерелаEstreptococos do grupo B (EGB) comumente colonizam adultos saudáveis, sem sintomas, mas sob certas circunstâncias possui a capacidade de invadir tecidos do hospedeiro, evadir da detecção imunológica e causar doenças invasivas graves. Por conseguinte, os EGB continuam sendo uma das principais causas de mortalidade neonatal, pneumonia, sepse e meningite. Contudo, a patogênese desta infecção ainda está pouco elucidada. O sorotipo V é freqüentemente associado à doença invasiva em mulheres adultas não gestantes e o segundo mais prevalente em mulheres grávidas. O principal objetivo deste trabalho foi estudar a aderência, invasão e persistência intracelular de amostras pertencentes ao sorotipo V (88641-vagina/portador e 90186-sangue/paciente) usando as células epiteliais respiratórias A549. As amostras de EGB demonstraram capacidade de aderir e invadir as células epiteliais A549, mas somente a amostra 90186-sangue apresentou maior invasão quando comparada com a de vagina (P <0.001). Ambas as amostras demonstraram persistência intracelular sem replicação no interior das células A549. Apenas o isolado 90186-sangue sobreviveu dentro das células epiteliais até 24h de incubação (P <0,05). A fusão dos lisossomas das células epiteliais com vacúolos contendo bactérias foi observada em células A549 tratadas com Lyso Tracker Grenn DND-26 para todas as amostras testadas. Nossos dados indicam pela primeira vez que as amostras viáveis do sorotipo V permanecem dentro de vacúolos ácidos epiteliais. Curiosamente, a amostra 90186- sangue induziu vacuolização celular e a amostra 88641-vagina promoveu a morte celular após 7h de incubação. Finalmente, nossos resultados aumentam o nosso conhecimento sobre eventos celulares da fagocitose e da patogênese das doenças invasivas promovidas pelos EGB.
Group B Streptococcus (GBS) commonly colonizes healthy asymptomatic adults, yetunder certain circumstances displays the ability to invade host tissues, evade the immune system and cause serious invasive disease. Consequently, GBS remains the major cause of neonatal pneumonia, sepsis and meningitis. However, the pathogenesis of this infection is poorly understood. The serotype V is frequently associated with invasive diseases in non-pregnant adults and the second most prevalent in pregnant women. The aim of this work was to study the adherence; invasion and persistence intracellular of the GBS serotype V (88641-vagina/carriers and 90186-blood/patient) in epithelial cells A549. All GBS strains showed ability to adhere and invade the epithelial A549 cells, but GBS 90186-blood was more invasive than the vagina isolate (P<0,001). Both strains persisted intracellular, but without replicating into the A549 cells. Only 90186-blood strain survived within epithelial cells even after a 24h incubation (P<0,05). Fusion of epithelial lysosomes with bacteria containing phagocytic vacuoles was observed in A549 cells treated with Lysotracker Grenn DND-26 for all strains tested. Our data indicate for the first time that viable strains of serotype V remain within acidic epithelial vacuoles. Interestingly, the 90186-blood strain induced cellular vacuolization and 88641-vagina strain caused cell death after 7h incubation. Lastly, our results increase our knowledge about cellular events of phagocytosis and pathogeneses of GBS diseases.
Huang, Bernice. "Anaplasma phagocytophilum remodels its host cell-derived vacuole into a protective niche by redecorating the vacuolar membrane with select Rab GTPases and bacterial proteins." VCU Scholars Compass, 2011. http://scholarscompass.vcu.edu/etd/280.
Повний текст джерелаLlinares, Elisa. "Function, regulation and intracellular trafficking of the vacuolaryeast pq-loop (Ypq) proteins." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209704.
Повний текст джерелаDuring this thesis work, we have studied three LCT proteins of the yeast Saccharomyces cerevisiae, named Ypq1, Ypq2 and Ypq3 (Yeast PQ-loop proteins 1, 2 and 3). We first showed that these proteins localize to the vacuolar membrane. We next studied the roles of these proteins, the regulation of their genes and the mechanisms and signals implicated in their delivery to the vacuolar membrane. We also contributed to the functional characterization of a mammalian homologue of yeast Ypq proteins, named rPqlc2.
In the first part of this work, we report that the Ypq proteins are most probably implicated in the export of basic amino acids from the vacuole to the cytosol. More precisely, Ypq2 and Ypq3 behave like vacuolar arginine and lysine exporters, respectively. Interestingly, the mammalian rPqlc2 protein expressed in yeast reaches the vacuolar membrane and functions as an orthologue of the Ypq proteins. Our results also reveal that the expression of the YPQ3 gene is regulated by the Lys14 transcription factor, responsible for the transcriptional activation of the LYS genes encoding enzymes implicated in the biosynthesis of lysine. We have also noted that, in general, the expression of the expression of the YPQ genes is regulated according to the quality of the nitrogen source available in the extracellular medium, eg. YPQ3 is sensitive to the nitrogen catabolite repression regulatory mechanism.
In the last part of this thesis work, we investigated the intracellular trafficking of the Ypq proteins and show that these predominantly reach the vacuolar membrane via the ALP (alkaline phosphatase) pathway due to the presence of a dileucine-based sorting signal in their sequences. Interestingly, a similar mechanism seems responsible for targeting to the yeast vacuole of the mammalian rPqlc2 protein.
Une caractéristique des cellules eucaryotes est leur organisation en compartiment internes délimité par une membrane lipidique, appelé organelles. Ces compartiments intracellulaires présentent une composition lipidique et protéique particulaire conforme à leur identité et fonction. Les lysosomes de cellules de mammifères et la vacuole fongique jouent un rôle clé dans la digestion intracellulaire de macromolécules et de ce fait leurs lumières sont enrichis d’enzymes hydrolytiques nécessaires à cette action. Des disfonctionnements du lysosome peuvent être la conséquence de pathologie chez l’homme, regroupé sous le nom de maladie lysosomale, lié à un à une accumulation de macromolécules non digéré ou un default d’export des produits d’hydrolysé depuis la lumière du lysosome. La cystinose est une maladie autosomale récessive avec une faible fréquence d’incidence (1/200 000) qui regroupe trois formes cliniques :deux formes rénales graves et une forme extra-rénale. Cette maladie est due à une accumulation et cristallisation de cystine dans la lumière du lysosome qui est corrélé à des mutations ponctuelles dans le gène CTNS qui code pour l’exporteur de cystine, la cystinosine. Cette protéine est un membre de la famille LCT (Lysosomal Cystine Transporter) qui possède des représentants chez les cellules animales, végétales et fongiques. Les protéines de la famille possèdent une taille et une topologie prédite similaire (7 segments transmembranaires) et on retrouve aussi au sein de ces protéines deux exemplaires de motifs PQ. Lors de ce travail de thèse nous nous sommes intéressés à trois membres de la famille LCT chez Saccharomyces cerevisiae que nous avons nommé Ypq1, Ypq2 et Ypq3 pour Yeast PQ-loop proteins. Ces protéines n’ayant pas fait l’objet de nombreuses études, nous nous sommes orientés vers une analyse fonctionnelle et transcriptionnelle. De plus, nous avons également étudié les mécanismes et signaux impliqué dans leur adressage vers la vacuole. Finalement, nous avons également inclus dans notre étude un homologue mammalien de ces protéines, rPqlc2.
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Doctorat en Sciences
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Silva, Luis Lamberti Pinto da. "The intracellular targeting of the plant vacuolar sorting receptor - BP80." Thesis, University of Leeds, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434757.
Повний текст джерелаHaider, Mustafa M. "The intracellular sorting of vacuolar proteins in the yeast Saccharomyces cerevisiae." Thesis, Durham University, 1989. http://etheses.dur.ac.uk/6495/.
Повний текст джерелаHenry, Thomas. "Physiologie de S. Typhimurium dans l'environnement intracellulaire : la division bactérienne et la modulation des moteurs moléculaires eucaryotes sur la vacuole contenant Salmonella." Aix-Marseille 2, 2005. http://theses.univ-amu.fr.lama.univ-amu.fr/2005AIX22030.pdf.
Повний текст джерелаGomord, Véronique. "Contrôle de l'adressage de la sporamine dans la cellule végétale." Rouen, 1994. http://www.theses.fr/1994ROUES054.
Повний текст джерелаWudick, Michael. "Intracellular aquaporins of Arabidopsis thaliana : dynamic expression in pollen and in roots under oxidative stress." Thesis, Montpellier, SupAgro, 2010. http://www.theses.fr/2010NSAM0008.
Повний текст джерелаAquaporins are membrane water channel proteins that mediate the fine-tuning of cell membrane water permeability during development or in response to environmental stresses. The dynamic expression of aquaporins in planta, as well as their role in plant water relations, were investigated in two representative model organs, the pollen and roots of Arabidopsis. Mature pollen consists of a vegetative cell and two sperm cells. Transcriptomics recently identified AtTIP1;3 and AtTIP5;1 as two pollen exclusive aquaporins. Here, we investigated their in vivo temporal and spatial expression pattern. Fluorescently-tagged chimeras revealed that AtTIP1;3 and AtTIP5;1 have a distinct and specific localisation in the vacuolar membrane of the vegetative and sperm cells, respectively. The two aquaporins also revealed the dynamic plasticity of vacuoles from pollen maturation to embryo fecundation. Loss of function approaches suggest an implication of both proteins in plant reproduction. The second part of this work focused on the oxidative stress-induced internalisation of root plasma membrane aquaporins and its concomitant drop in root hydraulic conductivity. The former process was described in great detail by combined biochemical, pharmacological and microscopic approaches. Co-expression analyses of the AtPIP2;1 isoform with endomembrane markers revealed that H2O2 triggers AtPIP2;1 accumulation in late endosomal compartments. This process could be antagonized by the auxin analog 1-NAA, but not by the endocytosis blocker tyrphostin A23. Life-time analyses established the high stability of the internalised protein suggesting that H2O2 triggers a mechanism for intracellular and reversible sequestration of plasma membrane aquaporins. Besides information on cell regulation of aquaporins, the overall work gives novel and complementary insights into the dynamic remodelling of plant internal membranes during development and stress responses
Delevoye, Cédric. "Identification de protéines sécrétées par Chlamydia et étude fonctionnelle d'une protéine insérée dans la membrane de la vacuole, à l'interface entre les bactéries et leur hôte." Paris 11, 2006. http://www.theses.fr/2006PA112017.
Повний текст джерелаChlamydiae are obligate intracellular pathogens of humans and animals. Depending on the species, they are responsible for ocular and genital infections, and respiratory diseases. After inducing their own entry, the bacteria develop in a membrane-bound compartment, called the inclusion. During the infectious cycle, they translocate a subset of proteins via a type three secretion (TTS) apparatus into the host cytosol. Among these, the Inc proteins remain anchored in the inclusion membrane where they face the host cytosol. My work has focused on bacterial proteins secreted into the host cell. By a global approach, we have identified 24 new proteins secreted by the TTS apparatus of Chlamydia. This work has opened the functional studies of these bacterial proteins that are in contact with the host cell cytosol. More specifically, we have studied the function of an inclusion protein, IncA. We have shown that IncA, from different chlamydial species, share structural and functional homologies with the SNARE family of eukaryotic proteins, which are essential factors for cellular membrane fusion events. We have shown that IncA interact with SNAREs in both a cellular and an in vitro model. Moreover, in liposome fusion assays, IncA inhibit membrane fusion induced by a cognate SNARE complex specific from the late endosomal compartment. We propose that IncA, by mimicking SNAREs proteins, participate in the control of the interactions between the inclusion membrane and intracellular compartments of the host cell
Kaneva, Galina. "Etude du lien entre le cytosquelette d'actine et les peroxysomes dans la levure Saccharomyces cerevisiae : et détermination du rôle intracellulaire de la myotubularine humaine dans le système modèle de levure Saccharomyces cerevisiae." Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13066.
Повний текст джерелаIn yeast Saccharomyces cerevisiae Las17p is the yeast homologue of WASP (Wiskott-Aldrich syndrome protein) in mammalian cells and a principal activator of actin polymerization Arp2/3 dependant that forms actin patches. Preliminary results from a GST pull-down assay in the laboratory had shown that Pex13p was able to interact, via its domain Src homology domain 3 (SH3), with Las17p. This study is based on the search for an eventual link between components of the actin polymerization machinery and peroxisomes. The peroxine Pex13p, together with Pex14p and Pex5p, is a part of the import complex at the peroxysomal membrane. My results favour the hypothesis that the actin cytoskeleton might regulate not the import into peroxisomes directly, but through an effect on peroxysomal biogenesis having an impact on peroxysomal size and number. Mutated forms of the hMTM1 gene are responsible for the X-linked myotubular myopathy (XLMTM) and it encodes a phosphoinositides phosphatase, a member of the myotubularine family, having an unique homologue in yeast S. Cerevisiae, Ymr1p. According to the results, heterologous expression of hMTM1 in yeast S. Cerevisiae leads to the production of an active enzyme, causing an enlarged vacuole phenotype. This phenotype is due to the phosphatase activity and therefore to the decrease in the level of PtdIns(3,5)P2. The results suggest a role for hMTM1 in membrane trafficking, in early and late endosome maturation and in maintaining vacuolar homeostasy
Canut, Hervé. "Proteolyse intracellulaire chez les vegetaux superieurs : role du compartiment vacuolaire." Toulouse 3, 1986. http://www.theses.fr/1986TOU30030.
Повний текст джерелаDenmat-Ouisse, Lise-Anne. "Rôle de la N-glycosylation et du repliement lors du transport des protéines solubles dans la cellule végétale." Rouen, 1998. http://www.theses.fr/1998ROUES044.
Повний текст джерелаSingh, Vikash. "Host factors and compartments accessed by Salmonella Typhimurium for intracellular growth and survival." Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2015. http://dx.doi.org/10.18452/17189.
Повний текст джерелаSalmonella spp. are invasive, intracellular pathogens which survive and proliferate within a membrane-bound compartment inside infected host cells. Like other intracellular pathogens, Salmonella replicates within this intracellular niche, despite its apparent isolation from both extra- and intracellular sources of nutrients. Here, we show that intracellular Salmonella acquire amino acids in the form of peptides by co-opting the host protein degradation pathway known as chaperone-mediated autophagy (CMA) involved in the transport of cytosolic proteins to the lysosome for degradation. A mutant of Salmonella strictly dependent upon peptides in growth media as a source of amino acids, showed intracellular growth similar to the wild-type strain in host cells, indicating intracellular access to peptides. We found that the Salmonella-containing vacuole (SCV) acquires the host cell proteins LAMP-2A and Hsc73, key components of CMA, but excludes lysosomal proteins such as LAMP-2B and LIMP-2. In contrast to wild-type Salmonella, the peptide-dependent mutant strain showed a severe reduction in growth when host cells were treated with inhibitors of CMA.. These results reveal a novel means whereby an intracellular pathogen can access the host cell cytosol to acquire nutrients from within its membrane-bound compartment. We suggest these results may provide an explanation for relapse infections resulting from persistent Salmonella infections, and suggest a possible means of targeting antibacterials against intracellular pathogens.
Valenzuela, Montenegro Camila. "Role of Salmonella enterica serovar Typhimurium effectors proteins SopB and SifA in the intracellular survival and modification of the vacuolar compartment in Dictyostelium discoideum." Tesis, Universidad de Chile, 2019. http://repositorio.uchile.cl/handle/2250/159544.
Повний текст джерелаSalmonella Typhimurium is an enteric pathogen able to infect different animal hosts, including humans. In immunocompetent humans, S. Typhimurium mainly causes gastroenteritis, a disease characterized by an inflammatory diarrhoea with massive neutrophil infiltration in the ileum and colon. The infective cycle of Salmonella starts with the ingestion of bacteria that reach the small intestine and invade epithelial cells by its apical face. After crossing the epithelial barrier, bacteria are captured by phagocytic cells of the immune system present in the sub-epithelium, such as macrophages, neutrophils and dendritic cells, being contained within a membrane bound compartment. Here, Salmonella subverts the endocytic route, avoiding the fusion of this compartment with the lysosomes and generating the Salmonella-containing vacuole (SCV). In this compartment, Salmonella is able to survive and replicate. The ability to modify this intracellular niche explains the ability of this pathogen to survive intracellularly. To carry out this process, Salmonella employs two Type Three Secretion Systems (T3SS) and an arsenal of secreted effector proteins in order to take control over the eukaryotic cell. An important aspect of Salmonella’s life cycle that has not been studied in detail is its survival in the environment, where bacteria are exposed to predation by protozoa, and specially by amoebae. These organisms are specialized phagocytes that feed on bacteria and fungi. To address this interaction, we and other groups use amoeba models to characterise the molecular processes involved in the survival of intracellular pathogens within environmental protozoa. Among these model organisms, the social amoeba Dictyostelium discoideum is amenable for molecular analyses in laboratory settings and several tools have been developed in this organism for the study of different aspects of its interaction with bacterial pathogens. Recently, our group described that S. Typhimurium is able to survive intracellularly in the social amoeba Dictyostelium discoideum, and that mutants in genes required for virulence in other infection models present survival defects in this host. Despite of this, the mechanisms that allow the intracellular survival of this pathogen in this kind of organism have not been studied in detail. This Thesis proposed the characterization at the cellular level of this interaction, with a focus on two secreted effector proteins of S. Typhimurium that are directly related to SCV generation and modification in other cell models: SopB and SifA. Our results show that these effectors are needed for intracellular survival of S. Typhimurium in D. discoideum. Furthermore, by means of a combination of microscopy and proteomic analyses we were able to characterise the protein composition of the vacuolar compartment containing Salmonella in this host. Our results show that known markers linked to this compartment in other cell types and the autophagy machinery play a role in the biogenesis of this intracellular niche in D. discoideum.
Salmonella Typhimurium es un patogeno enterico que tiene la capacidad de infectar diversos hospederos animals, incluyendo el ser humano. En individuos inmunocompetentes, S. Typhimurium provoca gastroenteriris, una enfermedad diarreica inflamatoria caracterizada por la masiva infiltracion de neutrofilos en el ileon y el colon. El ciclo infectivo de Salmonella comienza con la ingestion de las bacterias que al llegar al intestino delgado invaden las celulas epiteliales por la cara apical. Luego de cruzar la barrera epitelial, las bacterias son capturadas por las celulas fagociticas del sistema inmune que residen en el sub-epitelio, como macrofagos, neutrofilos y celulas dendriticas, quedando contenida en un compartimento membranoso. En esta etapa, Salmonella interviene la ruta endocitica, evitando la fusion de este compartimento con el lisosoma y generando la vacuola contenedora de Salmonella (Salmonella-containing vacuole: SCV). En este compartimento, Salmonella es capaz de sobrevivir y replicarse. La habilidad de modificar este nicho intracelular explica la habilidad de este patogeno de sobrevivir intracelularmente. Para esto, Salmonella utiliza dos Sistemas de Secrecion Tipo Tres (Type Three Secretion Systems: T3SS) y un arsenal de proteinas efectoras secretadas para tomar control sobre la celula eucarionte. Por otra parte, un importante aspecto del ciclo de vida de Salmonella que no ha sido estudiado en detalle es su supervivencia en el ambiente, donde las bacterias se encuentran expuestas a la depredacion por protozoos y en particular, amebas. Estos organismos son fagocitos profesionales que se alimentan de bacteria y hongos. Recientemente, nuestro grupo describio que S. Typhimurium es capaz de sobrevivir intracelularmente en la ameba social Dictyostelium discoideum y que mutantes en genes requeridos para la virulencia en numerosos modelos de infeccion tambien presentan defectos de supervivencia en este hospedero. A pesar de esto, los mecanismos que le permiten a este patogeno en este tipo de organismo no han sido estudiado en detalle. Para entender esta interaccion, nosotros y otros grupos usamos modelos de ameba a fin de caracterizar los procesos moleculares involucrados en la supervivencia de patogenos intracelulares en el interior de protozoos ambientales. Dentro de estos organismos modelo, la ameba social Dictyostelium discoideum es sencilla para el analisis molecular en condiciones de laboratorio. Por otra parte, numerosas herramientas se han desarrollado en este organismo para el estudio de diversos aspectos de su interaccion con patogenos bacterianos. Esta Tesis propuso caracterizar a nivel cellular esta interaccion, enfocandonos en dos proteinas efectoras secretadas de S. Typhimurium que estan directamente relacionadas a la formacion y modificacion de la SCV en otros modelos celulares: SopB y SifA. Nuestros resultados muestran que estos efectores son necesarios para que S. Typhimurium sobreviva intracelularmente en D. discoideum. Adicionalmente, mediante una combinacion de tecnicas de microscopia y analisis proteomicos pudimos caracterizar la composicion proteica de este compartimento vacuolar que contiene a Salmonella en este hospedero. Nuestros resultados muestran que marcadores asociados a la SCV en otras lineas celulares se encuentran en elcompartimento que se genera en D. discoideum y que la maquinaria de autofagia juega un rol importante en la biogenesis de este nicho intracelular en D. discoideum.
FONDECYT grants 1140754 y 1171844, CONICYT Doctoral Fellowship 21140615.
Enero 2020.
Lopez, Jodie. "Etude de l'impact du trafic intracellulaire et de la localisation des antigènes de Toxoplasma gondii sur leur présentation par les molécules du complexe d'histocompatibilité de classe I." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30100/document.
Повний текст джерелаCD8 T cells play a key role in protective immunity against intracellular pathogens such as Toxoplasma gondii (T. gondii) parasite. T. gondii resides inside host cell in parasitophorous vacuole. The host-T. gondii interface comprises a vacuole limiting membrane and a highly curved membraneous IntraVacuolar Network (IVN) of uncertain function. Many parasite effectors, including potential epitopes for CD8 T cells, are secreted by T. gondii to and across the boundary of their parasitophorous vacuole. Currently, the mechanisms controlling the targeting of parasite antigens to host cell are misunderstood et we don't kwnow how the intracellular transport of T. gondii proteins impacts on their access to MCH I pathway and their ability to induce CD8 T cell immunity. Using a multidisciplinary approach which combined reverse genetics in T. gondii, microscopy, antigen presentation measurements and in vivo experiments, I showed that insertion of a T. gondii dominant antigen at the vacuole limiting membrane is key for immunogenicity, yet that association of this antigen to high curvature IVN limits its presentation and curtails specific CD8 responses in mice. The IVN may play a role in immune modulation by limiting the access of parasite proteins to host cytosol and thus to MHC I pathway
Fugier, Emilie. "Analyse protéomique de la vacuole de Brucella abortus : la glycéraldéhyde-3-phosphate déhydrogénase (GAPDH) et la G Rab 2 sont indispensables pour sa réplication intracellulaire." Aix-Marseille 2, 2008. http://theses.univ-amu.fr.lama.univ-amu.fr/2008AIX22058.pdf.
Повний текст джерелаBrucella is a facultative intracellular pathogenic bacteria which causes severe infections and abortion in animals and a long-lasting febrile disease in humans. Essential to Brucella virulence is its ability to survive and replicate inside host cells. In vitro studies showed that Brucella initially avoids or escapes the endocytic pathway to ensure its intracellular survival both in phagocytic and nonphagocytic cells. Bacteria secure their replication via the biogenesis of an endoplasmic reticulumderived replicative organelle named “Brucella-containing vacuole” (BCV). Identification of specific proteins on the BCV membrane is essential to understand how Brucella sustain interactions with the endoplasmic reticulum (ER) and keeps replicating within its compartment. We characterize for the first time the protein composition of its replicative niche by proteomic approches. We developed a subcellular fractionation method to isolate BCVs. The analysis of BCV membrane proteins by 2 dimensional gel electrophoresis and mass spectrometry allowed the identification of several eukaryotic and prokaryotic proteins. We obtained ER proteins and ribosomal proteins that validate the model: the replicative niche of Brucella is an ER-derived vacuole. Furthermore, we have identified several interesting host proteins as well as some bacterial proteins that may contribute to Brucella virulence within host cells. We focused our study on two eukaryotic proteins: glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the small GTPase Rab 2, which are recruited to the vacuolar membrane of Brucella. This complex was previously described to localize on vesicular and tubular clusters (VTC) and to regulate the VTC membrane traffic between ER and Golgi. Disruption of the Golgi apparatus with prolonged brefeldin A treatment reduced B. Abortus replication. Furthermore, inhibition of GAPDH expression by small interfering RNA and blockage of Rab 2 GTPase in a GDP-locked form strongly inhibited B. Abortus replication. These results reveal an essential role for GAPDH and the small GTPase Rab 2 in B. Abortus virulence within host cells
Damasceno, Rosélia dos Santos. "Efeito da glicose sobre os mecanismos de extrusão de prótons em células MDCK." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/42/42137/tde-11082010-132441/.
Повний текст джерелаThis study investigated the effect of glucose on the activity and expression of Na+/H+ exchanger isoform 1 (NHE1) and vacuolar H+-ATPase, in Mardin Darby Canine Kidney (MDCK) cells from dog kidney, with similar characteristics to principal and intercalated cells of the distal nephron. The pHi recovery rate (dpHi/dt) and the buffering capacity (bi) was evaluated through fluorescence microscopy. From these parameters the H+ efflux (JH+) was calculated. By Western blot, the NHE1 and H+-ATPase (E subunit) expression was evaluated. Results: In the control situation the H+ efflux was 6.27 ± 0.51 mM/pH units (n = 9). Acute treatment with glucose (25 mM) increased the H+ efflux via NHE1, which was modulated by PI3 kinase. In the same condition, the H+-ATPase activity did not change. Chronic treatment with glucose (25 mM) induced significant increase in H+ efflux via NHE1 and H+-ATPase. The stimulatory effect of glucose on the NHE1 and H+-ATPase activity was dependent on p38 MAP kinase activity. Furthermore, chronic treatment with glucose (25 mM) induced Ezrin/radixin/moesin (ERM) and Akt phosphorylation. Conclusions: Our results indicate that during the acute treatment with glucose (25 mM), the NHE1 is modulated by PI3 kinase. However, during chronic treatment with glucose (25 mM), NHE1 activity was modulated by the ERM/Akt system and of H+-ATPase activity was modulated by p38 MAP Kinase.
Mudakavi, Rajeev J. "Development of anti-infective therapy against intracellular pathogens using targeted particulate delivery systems." Thesis, 2018. https://etd.iisc.ac.in/handle/2005/5342.
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