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1
Cordeiro, Cristianne. « Eggshell Membrane Proteins provide Innate Immune Protection ». Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33389.
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The microbiological safety of avian eggs is a major concern for the poultry industry and for consumers due to the potential for severe impacts on public health. Innate immune defense is formed by proteins with antimicrobial and immune-modulatory activities and ensures the protection of the chick embryo against pathogens. The objective of this project was to identify the chicken eggshell membrane (ESM) proteins that play a role in these innate immune defense mechanisms.
We hypothesized that ESM Ovocalyxin-36 (OCX-36) is a pattern recognition protein, and characterized purified ESM OCX-36. OCX-36 has antimicrobial activity against S. aureus and binds E. coli lipopolysaccharide (LPS) and S. aureus lipoteichoic acid (LTA). We additionally investigated the OCX-36 nonsynonymous single nucleotide polymorphisms (SNPs) at cDNA position 211. The corresponding isoforms (proline-71 or serine-71) were purified from eggs collected from genotyped homozygous hens. A significant difference between Pro-71 and Ser-71 OCX-36s for S. aureus LTA binding activity was observed. From these experiments, we confirmed the hypothesis that OCX-36 is a pattern recognition molecule. We also found that OCX-36 has anti-endotoxin properties and is a macrophage immunostimulator to produce NO and TNF-α. Digested OCX-36 down-regulated the expression of genes involved in LPS signaling and inflammatory responses. Moreover, OCX-36-derived peptides inhibited the production of LPS-induced pro-inflammatory mediators associated with endotoxemia in vivo.
Quantitative proteomics analysis of ESMs was performed to evaluate changes in ESM protein abundance during chick embryonic development. Bioinformatics analysis revealed enrichment of proteins associated with antimicrobial and immune protection, vascularization, calcium mobilization and lipid transport, which are vital for chick embryonic development. In unfertilized eggs, protease inhibitors and antimicrobial proteins were enriched.
In summary, the ESMs are enriched in proteins with antimicrobial, antioxidant and immune-modulatory properties, which aid in the development of the chick embryo and protect the embryo and unfertilized egg against pathogen invasion.
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Morgan, Cecilia A. « Treponema pallidum repeat protein K and heterologous protection against syphilis / ». Thesis, Connect to this title online ; UW restricted, 2002. http://hdl.handle.net/1773/9300.
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DeGroot, Andreas R. « Encapsulation of urease in alginate beads and protection from alpha-chymotrypsin with chitosan membrane ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0004/MQ44002.pdf.
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Westalle, Kim Louise. « The role of a Polyphenol from Myrothamnus flabellifolius in the protection of membranes during desiccation-using liposomes as a model membrane system ». Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/4351.
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Includes bibliographical references.A deficiency of water is a common stress experienced by plants. Dehydration of plant tissue results in altered protein and lipid ultrastructure responsible for membrane stabilisation leading inevitably to the death of the plant. Some plants known as resurrection plants have evolved with the ability to survive dehydration to less than 2% water content, a property known as desiccation tolerance. Recently a polyphenol extracted from the leaves of a common African resurrection tree Myrothamnus flabellifolius Welw. has been isolated and characterised as 3,4,5-tri-O-galloylquinic acid. This study has investigated the role which this polyphenol may play in desiccation tolerance.
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Paes, William Neville Wayne. « Immunisation with recombinant polymorphic membrane protein D elicits robust protection against sexually transmitted Chlamydia trachomatis infection ». Thesis, University of York, 2015. http://etheses.whiterose.ac.uk/11896/.
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Chlamydia trachomatis (Ct) is the most common sexually transmitted bacterial pathogen worldwide, responsible for ~90 million new cases of disease each year, with asymptomatic infections giving rise to sequelae such as pelvic inflammatory disease, ectopic pregnancy and infertility in women. Aggressive ‘seek and treat’ public health measures have not stemmed the rise of Ct infections, leading to proposal of the ‘arrested immunity’ hypothesis, where herd immunity within a population is blunted following earlier treatment with antibiotics. This suggests vaccination as the next key step in potentially eliminating Ct infections. Due to the paucity of robust clinical data, protective immune parameters have largely been derived from studies in mice, where pathogen-specific Th1-type immunity involving CD4+ T cells has been the focus of preclinical vaccine development. Our study represents the first preclinical characterization of a novel, rationally designed second-generation lipid adjuvant (SLA) in combination with the highly conserved recombinant Ct polymorphic membrane protein D (rPmpD) antigen. We demonstrate robust protection against urogenital Ct infection in the C57BL/6 murine model, characterized by significantly enhanced resistance to infection and reduction in mean bacterial load. However, enhanced Th1-type immunity was not found to correlate with relative protection, which rather coincided with the presence of robust rPmpD-specific serum and cervico-vaginal IgG titres. Prior to our study, the only convincing evidence of neutralizing antibodies effecting protection against chlamydial infection in vivo has emerged from studies employing the antigenically variable Ct MOMP as a vaccine immunogen. We propose that anti-rPmpD antibodies may play a significant role in vaccine-induced protection against urogenital Ct challenge, and that the role of antibodies warrants further investigation in future Ct vaccine development.
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Schirmacher, Anastasiya. « Modification of transmembrane peptides to probe SNARE-induced membrane fusion and cross-presentation of membrane-buried epitopes ». Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-1576-F.
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Vinci, Valentin. « Accumulateurs Li/S : barrières organiques à la réactivité des polysulfures ». Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI043/document.
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Les objectifs de ce travail de thèse étaient d’explorer de nouvelles voies pour l’amélioration des performances des accumulateurs Li/S, systèmes présentant de fortes densités d’énergie théorique dont les performances sont limitées par un mécanisme électrochimique incluant des intermédiaires solubles et réactifs. Ces intermédiaires induisent une faible efficacité coulombique et une perte importante de capacité au cours du cyclage. Plusieurs stratégies ont été mises en place pour créer une barrière de nature organique, au transport ou à la réactivité de ces polysulfures, tout en gardant une approche versatile et simple à mettre en œuvre. De bons résultats ont été obtenus en termes d’efficacité coulombique et de cyclabilité, notamment grâce à l’utilisation d’un matériau polymère capable d’interactions ioniques avec les intermédiaires soufrés. Le mécanisme de dépôt du lithium et de croissance dendritique a été également étudié, pour une compréhension plus complète du systèmeThe objectives of this thesis work were to explore new strategies to improve the performance of Li / S accumulators, systems exhibit with high theoretical energy densities whose performance is limited by an electrochemical mechanism including soluble and reactive intermediates. These intermediates induce a low coulombic efficiency and a significant loss of capacity during cycling. Several strategies have been evaluated to create a barrier of organic nature, which mitigate the transport or the reactivity of these polysulfides. The solutions explored are versatile and simple to implement. Good results have been obtained in terms of coulombic efficiency and cyclability, in particular through the use of a polymeric material enables to form ionic interactions with the sulfur intermediates. The mechanism of lithium deposition and dendritic growth has also been studied, for a more complete understanding of the system
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Colin, Julie. « Le vieillissement membranaire cérébral : conséquences fonctionnelles et protection par les acides gras polyinsaturés oméga-3 alimentaires ». Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0078/document.
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Un des phénomènes sociétaux marquants de ces dernières années est le vieillissement de la population et en conséquence, une hausse considérable du nombre de personnes âgées. Dans ce contexte, la recrudescence des pathologies chroniques liées au vieillissement, dont la maladie d’Alzheimer, est devenue un enjeu majeur de santé publique. L’impact de nombreux facteurs environnementaux modulables, l’aspect chronique et évolutif des mécanismes pathogènes mis en jeu, doivent inciter à développer des interventions préventives permettant de minimiser les risques de développer ces maladies liées au vieillissement. Ce travail nous a permis de mettre en évidence l’importance d’utiliser des modèles d’étude et des modes d’expérimentation adaptés au vieillissement pour espérer en ralentir ou retarder les processus délétères. Nos résultats ont aussi permis d’identifier les membranes comme des éléments essentiels au bon fonctionnement cérébral. L’altération de la composition et de l’architecture des membranes neuronales chez la souris âgée perturbe leurs fonctionnalités et diminue les capacités de réponse neuroprotectrices recherchées notamment lors des thérapies anti-Alzheimer. Nous avons aussi observé des modifications membranaires comparables chez les souris rendues dyslipidémiques par un régime alimentaire excessif en lipides saturés auquel nous avons pu clairement attribuer un rôle pro-vieillissement. Nous avons finalement démontré le potentiel préventif d’une supplémentation alimentaire en acide docosahexaénoïque, l’acide gras polyinsaturé à longue chaîne majoritaire dans le cerveau, et pu conclure en sa capacité de restaurer une réponse neuroprotectrice altérée chez la souris âgéeOne of the marked societal phenomena in recent decades is the aging of populations due to continually increasing lifespans and as a result, a considerable surge in the number and proportion of elderly, particularly in Western countries. In this demographic context, the rise of chronic diseases related to aging, including Alzheimer’s disease and other types of dementia, has become a major public health issue. The impact of modifiable environmental factors, evolution of the pathogenic mechanisms involved, and the lack of curative treatments illustrates the need for the development of interventions to prevent or delay the onset of these aging-related diseases. The present work demonstrates the importance of using age-adapted study models and experimental methods with the goal towards slowing or delaying age-related deleterious processes. Secondly, our results have identified membranes as an essential part for normal brain function. The composition and architectural changes in the neuronal membranes of elderly mice disrupt their functionality and reduce neuroprotective responsiveness such as those sought by anti-Alzheimer’s therapies. We also observed similar pro-aging-type changes in brain membranes of dyslipidemic mice fed a high-fat diet. Thus, disturbances of lipid homeostasis are correlated with an increased risk of developing aging-related cardiovascular and metabolic as well as neurodegenerative diseases. We finally demonstrated the preventive potential of dietary supplementation with docosahexaenoic acid, the most abundant long-chain polyunsaturated fatty acid in the brain, and observed its ability to restore a neuroprotective response that was impaired in older mice
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Messaoudi, Houssam mohammed. « Synthèse et caractérisation de membranes conductrices anioniques pour la protection d'électrode à air dans une batterie Zinc-Air fonctionnant sous air ambiant ». Thesis, Cergy-Pontoise, 2016. http://www.theses.fr/2016CERG0864.
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Différentes membranes conductrices anioniques ont été développées pour protéger une électrode à air fonctionnant dans une batterie Zinc-Air alimentée par de l’air ambiant. Dans ces conditions, le dioxyde de carbone contenu dans l’air, en contact avec l’électrolyte basique, se transforme en carbonate de potassium qui précipite dans la structure poreuse de l’électrode. Cela provoque l’augmentation de sa résistance et la perte de son étanchéité, et l’électrode n’est alors stable que 80 heures. L’objectif de cette étude est donc de rendre stable une électrode à air pendant 3000 heures de fonctionnement.Pour cela, différents réseaux (semi-)interpénétrés de polymères ont donc été développés en associant un polyélectrolyte et un réseau partenaire neutre. La polyépichlorhydrine greffée avec du 1,4-diazabicyclo(2,2,2)octane et un polyélectrolyte fluoré ont été choisis comme polymère conducteur anionique. Des réseaux neutres à base de poly(méthacrylate de 2-hydroxyéthyle), d’alcool polyvinylique et de perfluoropolyéther leur ont été, tour à tour, associés. Les propriétés physico-chimiques des différentes membranes développées ont été caractérisées selon leur densité de charges et leur composition. Les membranes présentant les meilleures propriétés requises (conductivité anionique, prise en masse limitée, sélectivité, …) ont ensuite été assemblées sur des électrodes à air dont le potentiel et la stabilité ont été évalués au cours du fonctionnement en demi-cellule. Ainsi, une électrode à air modifiée avec de telles membranes peut présenter un potentiel stable pendant 6800 heures de fonctionnement à -30mA/cm²Different anionic conducting membranes have been developed to protect an air electrode operating in a Zinc-Air battery fed with ambient air. Under those conditions, carbon dioxide from atmospheric air reacts with the alkaline electrolyte, and is then transformed into potassium carbonate. The precipitate of this carbonate inside the electrode porous structure leads to the increase of the system resistance and the loss of its sealing after 80 h of operation. The objective of this study focuses on the improvement of the stability of an air electrode for 3000 h of operation, by protecting it from carbonation reaction with a polymer membrane.For this, different (semi-)interpenetrating polymer networks have therefore been developed combining a polyelectrolyte and a neutral network partner. Polyepichlorohydrin grafted with 1,4-diazabicyclo (2,2,2) octane and a fluorinated polyelectrolyte were chosen as anionic conductive polymer. Neutral networks based on poly (2-hydroxyethyl methacrylate), polyvinyl alcohol and perfluoropolyether were then, alternately, associated to the polyelectrolyte. The physico-chemical properties of the various developed membranes were characterized according to their charge density and composition. The membranes with the best required properties (anionic conductivity, limited weight uptake, selectivity ...) were then assembled on air electrodes whose potential and stability have been evaluated during the operation in half-cell. Thus, an air electrode modified with such membranes maintains a stable potential during 6800 hours of running at -30mA / cm²
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El, Aidani Rachid. « Effet du vieillissement sur les propriétés de la membrane humidifuge en E-PTFE/NOMEX utilisée dans les vêtements de protection contre les incendies ». Mémoire, École de technologie supérieure, 2012. http://espace.etsmtl.ca/1017/1/EL_AIDANI_Rachid.pdf.
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La membrane humidifuge utilisée dans la confection des vêtements de protection contre les incendies joue un rôle très important dans la protection lors de l’utilisation en service. Cette membrane est généralement constituée d’une couche de polytétrafluoroéthylène expansé (e-PTFE) laminé sur un tissu en Nomex®. Notre étude s’est intéressée aux effets individuels et combinés de la température, rayonnement UV et l’humidité sur les performances de cette membrane. En effet, les propriétés de ce matériau peuvent évoluer dans le temps en fonction des conditions d’utilisation en service. Des vieillissements thermiques ont été réalisés à cinq températures (190, 220, 275, 300 et 320°C). Quatre intensités lumineuses (0,35, 0,68, 1 et 1,35 W/m2) à trois températures (50, 70 et 80°C) ont été utilisées pour le vieillissement photochimique accéléré et trois taux d’humidité relative ont été choisis (60, 80 et 100%) pour le vieillissement hydrolytique. Les propriétés mesurées incluent la résistance à la traction, la force de déchirure et la perméabilité à la vapeur d'eau. Des analyses physico-chimiques et morphologiques complémentaires ont également été effectuées.
Des réductions importantes des propriétés mécaniques de la membrane suite au vieillissement thermique, photochimique, hydrolytique et alterné ont été observées. Elles peuvent être attribuées entre autres à une dégradation des fibres de Nomex®. L'effet du vieillissement thermique accéléré sur les propriétés mécaniques de la membrane peut être décrit par la loi d'Arrhenius. D’autres modèles ont été élaborés pour prédire la durée de vie du vieillissement photochimique et l’effet synergétique de ces agents de vieillissement. En ce qui concerne la perméabilité à la vapeur d’eau, deux mécanismes concurrents ont été observés. D’une part, une fermeture des micropores de la membrane a été observée suite au vieillissement dans les températures les plus basses, impliquant une diminution de la perméabilité. D’autre part, des fissures dans la membrane apparaissent pour les plus hautes températures de vieillissement et/ou pour des temps d’exposition suffisamment longs. Les fissures produisent une très forte augmentation de la perméabilité, bien au-delà de la valeur observée sur la membrane neuve.
Les mesures par spectroscopie infrarouge (FTIR), diffraction aux rayons X (DRX), calorimétrie différentielle à balayage (DSC), microscopie électronique à balayage (MEB) et par microscopie à force atomique (AFM) mettent en évidence des modifications de la structure physicochimique au niveau des deux composants de la membrane suite aux traitements de vieillissement. Ces résultats permettent une meilleure compréhension des phénomènes se produisant lors du vieillissement de ce laminé microporeux à haute performance. Ils donnent également des outils pour contribuer à améliorer la sécurité des vêtements de protection contre l’incendie.
Un modèle mathématique permet de prédire la durée de vie de la membrane e-PTFE/Nomex® lors de son vieillissement en service a été utilisé à partir des données expérimentales collectées lors de cette étude, et en prenant le temps de vie correspondant à une diminution de 50% de la force de déchirure initiale. Il tient compte des effets synergétiques du vieillissement thermique, photochimique et hydrolytique.
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Ren, Xiaodi Ren. « Rechargeable Potassium-Oxygen Battery for Low-Cost High-Efficiency Energy Storage ». The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468857236.
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Falletti, Florence. « Etude de la régénération par microfiltration tangentielle sur membrane minérale des fluides de coupe aqueux et des solutions aqueuses de dégraissage ». Montpellier 2, 1990. http://www.theses.fr/1990MON20230.
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Les differentes categories de fluides de coupe aqueux (solutions, microemulsions, solutions) et solutions aqueuses de degraissage font partie des rejets d'un atelier d'usinage. Afin de diminuer le volume de ces fluides a rejeter et de remplacer les traitements de depollution par une technologie propre, nous avons etudie le procede de regeneration de ces fluides par microfiltration tangentielle sur membrane minerale. Nous avons utilise des membranes d'alumine (diametre de pores 0,8 micron) et de l'alumine enrobee d'autres oxydes (diametre de pores 3-5 microns). Le choix du diametre de pores est plus delicat pour les emulsions que pour les autres fluides, la membrane devant respecter la structure biphasique de l'emulsion, tout en retenant les polluants. A meme diametre de pores (5 microns), la coalescence des emulsions, lors de leur regeneration, est fonction de la nature chimique de la membrane. Pour tous nos essais, nous avons travaille a debit d'alimentation constant et nous avons suivi l'evolution de la pression en fonction du temps, ce qui permet de determiner la resistance intrinseque de la membrane, independamment des resistances additives qui evoluent au cours du temps. L'augmentation de pression, au cours du temps est due a la retention des polluants a la surface de la membrane. Ce colmatage membranaire depend, lors de la retention d'huiles, du degre d'hydrophilie de la membrane et de la quantite d'huiles dans le fluides avant regeneration. Les tensions interfaciales entre la membrane et les fluides filtres ont une influence importante sur les flux membranaires
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Wallart, Lisa. « Caractérisation du système BAC : vers l'hypothèse d'un système Psp original chez Pseudomonas aeruginosa ». Electronic Thesis or Diss., Normandie, 2023. http://www.theses.fr/2023NORMR119.
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L’émergence et la propagation des bactéries multirésistantes aux antibiotiques est devenue une problématique majeure de santé publique. En particulier, P. aeruginosa fait partie des pathogènes opportunistes humains pour lesquels il devient urgent de développer de nouvelles stratégies thérapeutiques. P. aeruginosa est un germe qui cible préférentiellement les individus dont le système immunitaire est affaibli. Ainsi, les patients atteints de mucoviscidose, d’un cancer, du SIDA, ou hospitalisés sur une longue durée sont des sujets à haut risque d’infection à P. aeruginosa. Chez ces patients, ces infections sont associées à une forte morbidité et mortalité, en raison de la persistance et de la résistance des bactéries colonisant les tissus de l’hôte sous forme de biofilms.Mes travaux de thèse s’inscrivent dans l’objectif de découvrir de nouvelles cibles pour le design de futurs traitements novateurs. Je décris dans ce manuscrit les derniers éléments de caractérisation du système BAC (pour « Biofilm Associated Cluster »), qui nous permettent de l’envisager comme un système Psp original. Ce système est ainsi constitué de 6 protéines codées par l’opéron bacABCDEF. L’expression de cet opéron se ferait en réponse à des stimuli et serait sous la dépendance du facteur sigma σ54 et du système à deux composants Gac/Rsm. La structure de BacA (protéine présentant un domaine DUF2170), nouvellement élucidée, est homologue à celle de protéines chaperonnes du SST3 suggérant que BacA serait impliquée dans la régulation de l’expression de bacABCDEF. La protéine BacB est quant à elle un homologue structural des protéines PspA et Vipp1 supposant que le système BAC serait impliqué dans la protection membranaire sous l’action d’un stress extra-cytoplasmique encore inconnu. La protéine BacD semble être une flotilline, protéine « échafaudage » connue pour résider dans les microdomaines fonctionnels, aussi appelés lipid raftsThe emergence and spread of bacteria that are multi-resistant to antibiotics has become a real public health concern. In particular, P. aeruginosa is one of the major human opportunistic pathogens for which it is urgent to develop new therapeutic strategies. P. aeruginosa is a microorganism that preferentially targets immuno-compromised individuals. Thus, patients suffering from cystic fibrosis, cancer, AIDS, or hospitalized for a long period are subjects at high risk of P. aeruginosa infection. In these patients, these infections are associated with high morbidity and mortality, due to the persistence and resistance of bacteria colonizing host tissues most often within biofilms.My thesis work is part of the objective of discovering new targets for the design of future innovative treatments. In this manuscript I describe the latest elements of characterization of the BAC system (for “Biofilm Associated Cluster”), which allow us to consider it as an original Psp system. This system is thus made up of 6 proteins encoded by the bacABCDEF operon. The expression of this operon would occur in response to stimuli and would be dependent on the sigma factor σ54 and the Gac/Rsm two-components system. The structure of BacA (protein presenting a DUF2170 domain), newly elucidated, is homologous to that of T3SS chaperone proteins suggesting that BacA is involved in the regulation of bacABCDEF expression. The BacB protein is a structural homolog of the PspA and Vipp1 proteins, suggesting that the BAC system is involved in membrane protection under the action of a yet unknown extra-cytoplasmic stress. The BacD protein appears to be a flotillin, a “scaffolding” protein known to reside in functional membrane microdomains, also called lipid rafts
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Morel, Aude. « Gestion des transferts thermiques et hydriques au sein d’une structure multicouche textile : développement d’une membrane pour application EPI ». Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10124/document.
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L'objectif de cette étude est d'élaborer une membrane thermosensible permettant une perméabilité à la vapeur d'eau contrôlée pour améliorer le confort et la sécurité des sapeurs-pompiers. Plusieurs membranes à base de polyuréthane segmenté ont été synthétisées. L'influence du type de polyol utilisé et sa longueur, et de la quantité de segments rigides a été étudiée. Deux types de mécanisme apparaissent selon la structure chimique du polymère, i.e. une modification en masse et une modification de surface. Celles-ci changent les propriétés de diffusion de l'humidité à travers la membrane. Ces membranes ont ensuite été complexées sur un textile pour renforcer la tenue mécanique, en vue de la confection de la couche entre le sous-vêtement et la veste des sapeurs-pompiers. Ce procédé modifie peu les propriétés des membranes et les produits obtenus semblent présenter une perméabilité à la vapeur d'eau contrôlée en fonction de la températureThis study aims at developing a thermosensitive membrane allowing the water vapor to cross with a function of the temperature to enhance the comfort and the safety of firefighters. Membranes with different chemical structure were synthesized from segmented polyurethane. The influence of the polyol type and its length, and the hard segment content was studied. Two kinds of mechanisms were identified depending on the chemical structure as a bulk modification and a surface modification, that change moisture management properties. Afterwards, membranes were pressed on a textile for higher mechanical properties. The purpose of the final product is to be made inside the firefighter’s personal protective equipment, between the underwear and the jacket. The systems membrane-textile keep the properties of the membrane and present controlled water vapor permeability with the function of the temperature
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Ke, Lijing. « Mechanism of anti-influenza virus activity of Maillard reaction products derived from Isatidis roots ». Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/6501.
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The cyto-protective compositions and effects of antiviral Maillard reaction products (MRPs) derived from roots of Isatis indigotica F. were examined using biochemical and biophysical methods. The Maillard reaction was identified as the main source of compounds with antiviral activity, an observation which has led to the proposal of a new class of active compounds that protect cells from influenza virus infection. In the roots, arginine and glucose were revealed to be the predominant reactants for the Maillard reaction. Significant anti-influenza virus effects were demonstrated in the RIE MRPs derived from the roots (RIE refers to the ‘radix Isatidis extracts’), and in Arg-Glc MRPs which are synthesised with arginine and glucose. Arg-Glc MRPs were confirmed as suitable models for the study of the antiviral effects of the root extracts. Furthermore, RIE MRPs and Arg-Glc MRPs were found to bind to the plasma membranes of erythrocytes and MDCK cells, and altered their properties. A novel antiviral mechanism was proposed: that MRPs achieve their cyto-protective effects by binding to the cell membrane rather than by direct action on viral particles. To validate the proposed mechanism, the interaction between MRPs and membrane lipids was investigated by biophysical experiments with phospholipids bilayers. Arg-Glc MRPs affected the rigidity of lipid packing in monolayers and bilayers, while RIE MRPs enhanced the fluidity. Both types of MRPs inserted into the hydrophobic core of bilayers, to differing extents, and induced the stabilisation or destabilisation of bilayers in a concentrationdependent manner. At certain concentrations, MRPs prevented the lamellar structure of bilayers from being destabilised by a viral fusion peptide, improved the lipid order and thereby inhibited cell-virus membrane fusion. The mechanism of the anti-influenza virus activity of RIE was therefore correlated to the interaction between MRPs and phospholipid bilayers, an integral component of the plasma membrane.
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Sevestre, Julien. « Epidémie clonale d'infections invasives à méningocoque de groupe B en Normandie : caractérisation d'un facteur de virulence - HmbR, système d'acquisition du fer via l'hémoglobine - et analyse de la protection conférée par un vaccin à base de vésicules de membrane externe ». Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR047/document.
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Ce travail de thèse comporte deux volets ayant pour trait commun l’analyse a posteriori d’une épidémie d’infection invasive à méningocoque (IIM) survenue en Normandie entre 2003 et 2012 et liée à l’expansion d’un clone hypervirulent particulier (B:14:P1.7,16/ST-32 ). Le premier travail (publié dans Virulence : Sevestre et al 2018 ;9 :923-929) s’est focalisé sur les déterminants de la virulence de « B14 » en comparant 6 isolats identifiés les uns d’IIM, les autres de portage pharyngé sain (ces derniers exprimant ou non la capsule). Apparemment identiques selon le typage classique (immunotypage et génotypage par MLST), ces 3 groupes bactériens se sont révélés distincts après analyse génomique et comparaison gène par gène (plus de 600 gènes au profil génétique variable entre les groupes) conduisant à identifier le rôle majeur de l’acquisition du fer dans la virulence et en particulier celui du système HmbR, un récepteur de l’hémoglobine. Dans un modèle murin (souris transgéniques rendues sensibles à l’infection humaine) les 3 groupes de souches sont aussi apparus distincts, avec une hiérarchie des marqueurs d’infectiosité (titres bactériens, taux de cytokines). La restauration du système HmbR (souches de portage capsulées « Off » dérivées en « On ») a restauré le pouvoir invasif in vitro et chez l’animal. Si le fer était déjà connu comme facteur de virulence pour différentes espèces bactériennes, l’originalité ici est d’avoir identifié le rôle de la variation de phase du gène hmbR au sein d’un même clone épidémique, permettant l’adaptation au portage, condition sine qua non de la transmission d’individu en individu. Le second travail (publié dans Vaccine : Sevestre et al 2017 ;35 :4029-4033) s’est intéressé à la durabilité et à l’ampleur de la protection vaccinale du MenBvac®, vaccin à base de vésicules de membranes externes (Outer Membrane Vesicles, OMV) utilisé jadis pour contrôler l’épidémie. Ceci a pu être réalisé grâce à deux cohortes d’enfants vaccinés par un schéma à 4 doses et prélevés pour les uns 1 an après la dernière dose et pour les autres 4 an après. L’immunogénicité (étude de l’activité bactéricide du sérum vis-à-vis du clone ciblé) s’est avérée de durabilité moyenne avec 48% des enfants protégés à 1 an et 31% à 4 ans, un résultat en phase avec les données de la littérature sur les vaccins OMV. Un effet bactéricide fut observé très au-delà de « B14 », du fait d’une immunité croisée aux souches avec une homologie au moins partielle de la porine PorA (principal déterminant antigénique des vaccins OMV) soit pour le MenBvac® 15% des clones virulents B actuellement circulants en France, un résultat davantage original car ayant jusqu’alors que peu investiguéThis thesis work includes two studies which both contribute to analyze a posteriori an outbreak of invasive meningococcal diseases (IMD) that had occurred in Normandy from 2003 to 2012 due to the expansion of a single hypervirulent clone (B:14:P1.7,16/ST-32 ). The first work (published in Virulence: Sevestre et al 2018 ;9 :923-929) focused on the virulence determinants of “B14” by comparing 6 isolates, either from IMD or from asymptomatic carriage (these latter expressing or not the capsule). Apparently identical on the basis of classical typing methods (immunotyping and MLST genotyping), these 3 groups of isolates were markedly different by whole genome analysis and on gene by gene comparison (more than 600 genes presenting a variable genetic profile). This analysis leaded to identify the crucial implication of iron acquisition in virulence and in particular the place of the HmbR system, an hemoglobin receptor. In a murine model (transgenic mice made susceptible to infection), these 3 groups also appeared separated, with a distinct infectivity hierarchy (bacterial counts, levels of cytokines). The restoration of the HmbR system in the capsulated carriage isolates (switch from Off phase to On phase) also restored their invasiveness in vitro and in vivo. Even if iron is already known to be a determining factor in the virulence of many bacterial species, our results clearly indicate the importance of the hmbR phase variation among clonal epidemic isolates, allowing adaptation to carriage, sine qua non condition for people to people transmission. The second work (published in Vaccine: Sevestre et al 2017 ;35 :4029-4033) concerned the durability and the cross-protection of the MenBvac®, an OMV vaccine (Outer Membrane Vesicles), used in the past to control the outbreak. This work has been done thanks to 2 cohorts of children vaccinated with 4 doses and sampled either 1 year or 4 years after the last dose. The efficacy (serum bactericidal activity against the epidemic strain) was short lasting, with 48% of children protected after 1 year and 31% after 4 years, a result in accordance with OMV literature. A bactericidal effect was observed far beyond “B14”, by cross-immunity with strains harboring homologies, even partials of the porin PorA (main antigenic determinant in OMV vaccine), indicating a coverage for 15% of virulent isolates B circulating in France, an original result as until then not so far investigated
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Woodall, Alan Anthony. « Carotenoids and the protection of membranes against oxidative damage ». Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240900.
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Boulaud, Romain. « Etudes et modélisations du comportement d’un écran de filet pare-blocs à différentes échelles ». Thesis, Paris Est, 2020. http://www.theses.fr/2020PESC2017.
Texte intégralRésumé :
Les écrans de filet pare-blocs sont des ouvrages de protection souples utilisés pour protéger les habitants ainsi que leurs biens du danger des éboulements rocheux dans les régions à risques. Ces structures placées sur la trajectoire des masses en mouvement sont formées d’un filet métallique maintenu au terrain naturel par des poteaux rigides. Lorsqu’elles sont impactées par un bloc, elles subissent des grandes déformations qui nécessitent de modéliser leur comportement en tenant compte de non-linéarités à la fois géométriques et matérielles. Leurs composants sont ainsi représentés dans ce travail par des éléments discrets et le problème mécanique est résolu quant à lui avec un outil de calcul numérique adapté aux grandes transformations. Cet algorithme est ensuite utilisé pour évaluer l’influence de différentes stratégies de modélisation de la nappe de filet, toutes tirées de la littérature scientifique, sur le comportement global d’un écran de protection pare-blocs. Les conclusions de cette étude ainsi que des observations expérimentales ouvrent la voie vers de nouvelles stratégies de modélisation discrète, pour lesquelles le filet est représenté par un nombre restreint de degrés de liberté. La famille de modèles simplifiés développée dans ce travail permet de simuler le comportement d’un ouvrage avec des faibles coûts en temps de calcul, offrant ainsi l’opportunité de mettre en œuvre des études paramétriques complexes et des méthodes de dimensionnements probabilistesRockfall barriers are flexible structures that mitigate the risk of rockfall and thus protect people living in risk areas, as well as their property. These structures, placed on the trajectories of the moving blocks, are made of a steel net held on the natural ground by rigid posts. When they are impacted, they undergo large deformations that require modelling their behaviour by taking into account both geometric and material non-linearities. Their components are therefore represented in this work with discrete elements and the mechanical problem is thus solved with a calculation tool adapted to the large déformations problem. This algorithm is also used to assess the influence of different net modelling strategies, from the scientific literature, on the overall behaviour of a rokfall barrier. The conclusions of this study as well as experimental observations pave the way to new discrete modelling strategies, for which the net is represented by a limited number of degrees of freedom. The family of simplified models developed in this work makes it possible to simulate the behaviour of a structure with a low computation time costs, thus offering the opportunity of implementing complex parametric studies or probabilistic dimensioning methods
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Turel, Tacibaht Gowayed Yasser. « Gas transmission through microporous membranes ». Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/FALL/Polymer_and_Fiber_Engineering/Dissertation/Turel_Tacibaht_38.pdf.
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Setchfield, Kerry Jane. « Identification of Neisseria lactamica outer membrane proteins protective against meningococcal disease ». Thesis, Open University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395260.
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Portier, Laurent. « Sécurité automobile et protection des membres inférieurs ». Paris 12, 1997. http://www.theses.fr/1997PA120008.
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Il s'agit d'ameliorer les vehicules en ce qui concerne les lesions des jambes (tibia et perone), des chevilles et des pieds, en utilisant les bases de donnees accidentologiques, les essais de choc, des simulations mathematiques et des experimentations biomecaniques necessaires pour determiner des criteres de tolerance applicable aux mannequins de choc. A partir des bases de donnees accidentologiques, l'ampleur, la nature et les mecanismes de lesions de la jambe (compares avec le genou, le femur et le bassin) sont determines. Dans l'etude biomecanique, deux types de problemes sont consideres : le comportement du pied une surface plus ou moins inclinee et la tolerance lors de mouvements extremes. (a) les pieds de 6 cadavres et d'un mannequin sont charges par un plancher simplifie equipe d'une pedale de frein, l'ensemble etant monte sur une catapulte. (b) un mouvement dynamique de dorsiflexion est impose dans les articulations de la cheville de 5 cadavres complets, a l'aide d'une tige guidee chargeant le pied sous les tetes des metatarsiens. Un capteur d'effort 6-axes, implante dans le tibia des cadavres et laissant toute la musculature intacte, permet la mesure des efforts et des moments dans l'articulation de la cheville. Un effort musculaire passif jusqu'a 1. 9 kn est transmis dans le tendon d'achille lors d'un mouvement dynamique de dorsiflexion de la cheville. De nombreuses proprietes geometriques et mecaniques sont fournies pour le cadavre et les mannequins (voir aussi these de philippe petit, fin 1997). Cette etude a permis d'assurer la mise en place, dans le nouveau reglement europeen en choc frontal utilisant une barriere deformable, d'un critere acceptable mesure sur le mannequin actuel modifie. Ces donnees sont utiles dans l'evaluation des nouveaux prototypes de mannequins, la validation des modeles mathematiques de la cheville, et l'elaboration pour le vehicule d'un cahier des charges concernant la protection des jambes au cours d'un choc automobile.
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Plasse, Robert. « Vegetable storage, respiration and design criteria in a membrane storage system ». Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65519.
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Cam, Doruk. « Understanding the role and improving the properties of a protective barrier membrane for a bioartificial pancreas ». Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/11309.
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Caudill, Landon S. « PRESSURE-DRIVEN STABILIZATION OF CAPACITIVE DEIONIZATION ». UKnowledge, 2018. https://uknowledge.uky.edu/me_etds/113.
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The effects of system pressure on the performance stability of flow-through capacitive deionization (CDI) cells was investigated. Initial data showed that the highly porous carbon electrodes possessed air/oxygen in the micropores, and the increased system pressure boosts the gases solubility in saline solution and carries them out of the cell in the effluent. Upon applying a potential difference to the electrodes, capacitive-based ion adsorption occurs in competition with faradaic reactions that consume oxygen. Through the addition of backpressure, the rate of degradation decreases, allowing the cell to maintain its salt adsorption capacity (SAC) longer. The removal of oxygen from the pore space of the electrodes makes it no longer immediately accessible to faradaic reactions, thus hindering the rate of reactions and giving the competing ion adsorption an advantage that is progressively seen throughout the life of the cell. A quick calculation shows that the energy penalty to power the pump is fairly insignificant, especially in comparison to the cost of replacing the electrodes in the cell. Thus, operating at elevated pressures is shown to be cost effective for continuous operation through the reduced electrode replenishment costs.
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Boca, Simona. « Tolerance of Arabidopsis thaliana to photo-oxidative stress : protection mechanisms of chloroplast membranes against lipid peroxidation ». Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4005.
Texte intégralRésumé :
Dans les conditions naturelles, les plantes sont soumises à des conditions environnementales très variées qui peuvent conduire à un excès d'énergie dans les chloroplastes, résultant en une production d'espèces réactives de l'oxygène (ERA). Pour faire face à ces ERA, les plantes ont développé différents mécanismes de protection, comme des alkénal réductases, des peroxyrédoxines et des lipocalines. Le travail présenté dans cette thèse a pour but de caractériser et de déterminer leur importance dans la protection des contre les stress oxydants. Une analyse préliminaire de mutants d'Arabidopsis a mis en évidence le rôle important des peroxyrédoxines à 2 cystéines et des lipocalines dans la tolérance au stress photooxydant. Cette thèse s'est surtout concentrée sur les lipocalines. Deux lipocalines ont été récemment identifiées chez les plantes, TIL (lipocaline thermoinduite) et CHL (chloroplastique), toutes les deux induites par des conditions de stress. Chez Arabidopsis, chaque lipocaline semble être spécialisée dans la réponse à des conditions différentes: chaleur (AtTIL) et fortes lumières (AtCHL). Le double mutant AtCHL KO × AtTIL KO est plus sensible à la chaleur et la forte lumière que les simples mutants. La mutation de AtCHL a augmenté fortement la photosensibilité de mutants (vte1, npq1) affectés dans des mécanismes de protection des lipides (tocopherols, zéaxanthine), confirmant ainsi le rôle des lipocalines dans la protection contre la peroxydation lipidique. Les résultats obtenus dans cette thèse montrent que les lipocalines AtTIL and AtCHL ont des fonctions redondantes dans la protection des lipides qui sont essentielles à la résistance des plantes au stressUnder field conditions, plants are exposed to various environmental conditions that can lead to an excess of energy in the chloroplasts, resulting in the production of toxic reactive oxygen species (ROS). To cope with the harmful effects of ROS, plants have developed various protection mechanisms, such as alkenal-reductases, peroxiredoxins and lipocalins. The work performed in this thesis aimed at understanding their importance in the protection against lipid peroxidation. A first screening of Arabidopsis mutants lacking one of those mechanisms brought into light that 2-Cys PRX and lipocalins are important for the tolerance against photooxidative stress. This thesis is focused mainly on lipocalins, a group of proteins recognized as carriers of small lipophilic molecules. However, two true lipocalins have been recently identified in plants, the temperature-induced lipocalin (TIL) and the chloroplastic lipocalin (CHL), their expression beeing induced by various abiotic stresses. Each lipocalin appeared to be specialized in the responses to specific stress conditions in Arabidopsis, with AtTIL and AtCHL playing a protective role against heat and high light, respectively. The double mutant AtCHL KO × AtTIL KO deficient in both lipocalins was more sensitive to temperature, drought and light stresses than the single mutants. Seeds of the AtCHL KO × AtTIL KO double mutant were very sensitive to natural and artificial aging, and again this phenomenon was associated with the oxidation of polyunsaturated lipids. The results obtained in this thesis show that AtTIL and AtCHL have overlapping functions in lipid protection which are essential for stress resistance and survival
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Morton, J. D. « The effect on protein synthesis in barley of infection with P. hordei ». Lincoln College, University of Canterbury, 1989. http://hdl.handle.net/10182/1950.
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Infection of barley (Hordeum vulgare) leaves with the rust fungus, Puccinia hordei, causes changes in the host protein synthesis. This thesis analyses these changes in the barley cultivar Triumph following inoculation of 7-day-old leaves with either a virulent or an avirulent race of P. hordei. The initial approach was to isolate membrane-bound polysomes from infected leaves, translate them in vitro and analyse the translation products. These products include the integral membrane proteins which were expected to be involved in the response of the host to the pathogen. A method based on differential centrifugation in the presence of a ribonuclease-inhibiting buffer was developed for separating membrane-bound polysomes from the rest of the cytoplasmic polysomes. Membrane-bound polysomes were found to comprise one fifth of the total polysomes in the leaves. Analysis of the translation products of membrane-bound polysomes by SDS-PAGE showed them to be of higher average molecular weight than those from free polysomes. Comparison of polypeptides produced by membrane-bound polysomes from healthy and inoculated plants showed some differences however the low yield of membrane-bound polysomes made it difficult to obtain conclusive results. Thus it was decided to isolate total polysomes by including 1% Triton X-100 in the extraction buffer. Polysomes were extracted from 12 to 72 h after inoculation. Infection caused a decline in yield of polysomes during this period when compared with healthy leaves of the same age. Polysomes isolated 16 h after inoculation with the virulent race were 20% less efficient at translation than polysomes from control leaves. In contrast polysome isolated from leaves inoculated with the avirulent race were 20% more efficient. Analysis of the labelled translation products by SDS-PAGE and fluorography showed relative increases in the synthesis of some proteins by 16 h after inoculation with either race when compared to products from healthy leaves. Protein synthesis in the infected plants was further analysed by in vivo labelling and one- and two-dimensional PAGE. The fluorographs revealed increased synthesis of a group of proteins from 58 to 116 kDa starting 12 h after inoculation with either race of P. hordei; confirming the results from the polysome translations. Two polypeptides with molecular weights of about 66 kDa were found to increase following infection only with the virulent race. By three days after inoculation with either fungal race the most obvious change in protein synthesis was a marked decrease in the synthesis of the two most prominent polypeptides with molecular weights of 15 and 51 kDa which were considered to be the subunits of ribulose bisphosphate carboxylase. The elicitor hypothesis, in attempting to explain cultivar-specific resistance in plants, postulates that resistance is controlled by the interaction of specific fungal elicitors and plant receptors and that this interaction which only occurs between resistant hosts and avirulent pathogens triggers specific gene expression leading to resistance. This hypothesis does not fit the situation in the barley-P. hordei interaction as protein synthesis showed similar changes following infection with either a virulent or an avirulent race.
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Phromphen, Phannaphat. « The permeation and moisture transmission properties of a thermosensitive membrane barrier for chemical protective clothing ». Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/12002/.
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The liquid chemical permeation properties and water vapour transmission properties of temperature sensitive poly(vinylidene fluoride) (PVDF) grafted N-isopropylacrylamide (NIPAAM) (NIPAAM-g-PVDF) copolymer membranes as a smart barrier layer in chemical protective clothing are studied in this research. Both modified thermally induced method and modified plasma induced method are employed to oxidise PVDF polymer for its copolymerisation with NIPAAM monomers. In the thermal induced method, NIPAAM-g-PVDF polymer materials are synthesised via the copolymerisation of ozone activated PVDF polymer with NIPAAM monomers below a lower critical solution temperature of NIPAAM (30°C). An effective supercritical carbon dioxide drying method is used as an alternative drying method to remove the solvent from the ozone activated PVDF polymer in conventionally copolymerisation is successfully applied and a new direct copolymerisation route by adding NIPAAM polymer into ozone activated PVDF in solutions without the drying process of the activated PVDF polymers. The NIPAAM-g-PVDF made by the new copolymerisation process is much simpler than the conventional method and the processing time needed is much shorter. In the oxygen plasma induced copolymerisation method, the porous PVDF membranes produced from the phase inversion method are treated oxygen plasma before they were copolymerised with NIPAAM monomer in N,N-dimethylformamide (DMF) solvent aqueous solution below the lower critical solution temperature of NIPAAM (30°C). The structural characteristics of heat-pressed NIPAAM-g-PVDF nanoporous membranes produced from the above two methods are investigated. The influence of the microstructure of the nanoporous copolymer membranes on both their water vapour transfer properties and dynamic permeation rate has been studied. The mechanisms of liquid/vapour permeation through the thermal sensitive copolymer nanoporous membranes are analysed and investigated. In this study, it is found that the breakthrough time and permeation rate of nanoporous NIPAAM-g-PVDF membranes are influenced by the proportion of NIPAAM components, the membrane thickness, the crystallinity and the porous structure of the NIPAAM-g-PVDF membranes. It is also found that the water vapour permeability of the heat-pressed NIPAAM-g-PVDF membranes at both 20°C and 40°C are influenced by the membrane thickness, the total pore volume and the porosity of the membranes. The water vapour permeability coefficient of the NIPAAM-g-PVDF nanoporous membranes is determined by both the proportion of thermal sensitive NIPAAM components and associated porous structure of the copolymer membranes.
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Crouchman, Sophie Jane. « Role of the PsbS protein in protective energy dissipation in the photosynthetic membrane in higher plants ». Thesis, University of Sheffield, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440942.
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Ganfini, Luisa. « Studies on the synergistic protective activity of cancer antigens associated to engineered bacterial Outer Membrane Vesicles ». Doctoral thesis, Università degli studi di Trento, 2017. https://hdl.handle.net/11572/368961.
Texte intégralRésumé :
Introduction
Bacterial Outer Membrane Vesicles (OMVs) are naturally produced by all Gram-negative bacteria and are emerging as an attractive vaccine platform. The exploitation of OMVs in cancer immunotherapy was tested by decorating them with cancer epitopes and by following their capacity to elicit protective immune responses, alone or in combination, using cancer mouse models. Furthermore, we tested whether cancer cell-derived exosomes (TEXs) and OMVs can form complexes and whether such complexes, which carry TEX- associated tumor antigens and OMV-associated immune-stimulatory molecules, elicit anti-tumor immune responses in vivo. Results
Immunization with OMVs engineered with two B cell epitopes (EGFRvIII and D8-mFAT1) induced tumor growth inhibition after mouse challenge with cell lines expressing the corresponding epitopes. Furthermore, mice immunized with engineered OMVs carrying two cancer epitopes, the EGFRvIII B cell epitope and the M30 CD4+ T cell epitope, were completely protected from EGFRvIIIB16F10 cell line expressing both epitopes, indicating the importance of multi-antigen immunization in cancer immunotherapy. Furthermore TEXs- OMVs immunization induced antibody responses against exosome antigens with a Th1-type profile. Finally, the combination of CT26-derived TEXs and MBP-D8-mFAT1 OMVs elicited synergistic protective activity against mouse challenge with CT26 cell line.
Conclusions
OMVs decorated with tumor antigens elicit antigen-specific, protective anti- tumor responses in mice. The synergistic protective activity of multiple epitopes simultaneously administered with OMVs, either by direct OMV engineering or by TEX-OMV combination, demonstrates the attractiveness of the OMV platform in cancer immunotherapy.
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Ganfini, Luisa. « Studies on the synergistic protective activity of cancer antigens associated to engineered bacterial Outer Membrane Vesicles ». Doctoral thesis, University of Trento, 2017. http://eprints-phd.biblio.unitn.it/2716/1/CONFIDENTIAL_PhD_thesis.L.Ganfini_.pdf.
Texte intégralRésumé :
Introduction
Bacterial Outer Membrane Vesicles (OMVs) are naturally produced by all Gram-negative bacteria and are emerging as an attractive vaccine platform. The exploitation of OMVs in cancer immunotherapy was tested by decorating them with cancer epitopes and by following their capacity to elicit protective immune responses, alone or in combination, using cancer mouse models. Furthermore, we tested whether cancer cell-derived exosomes (TEXs) and OMVs can form complexes and whether such complexes, which carry TEX- associated tumor antigens and OMV-associated immune-stimulatory molecules, elicit anti-tumor immune responses in vivo. Results
Immunization with OMVs engineered with two B cell epitopes (EGFRvIII and D8-mFAT1) induced tumor growth inhibition after mouse challenge with cell lines expressing the corresponding epitopes. Furthermore, mice immunized with engineered OMVs carrying two cancer epitopes, the EGFRvIII B cell epitope and the M30 CD4+ T cell epitope, were completely protected from EGFRvIIIB16F10 cell line expressing both epitopes, indicating the importance of multi-antigen immunization in cancer immunotherapy. Furthermore TEXs- OMVs immunization induced antibody responses against exosome antigens with a Th1-type profile. Finally, the combination of CT26-derived TEXs and MBP-D8-mFAT1 OMVs elicited synergistic protective activity against mouse challenge with CT26 cell line.
Conclusions
OMVs decorated with tumor antigens elicit antigen-specific, protective anti- tumor responses in mice. The synergistic protective activity of multiple epitopes simultaneously administered with OMVs, either by direct OMV engineering or by TEX-OMV combination, demonstrates the attractiveness of the OMV platform in cancer immunotherapy.
31
Li, Ze Sheng. « Caractéristiques et régulations des transports membranaires au cours du développement de péricarpe de la gousse de Vicia Faba L ». Poitiers, 1987. http://www.theses.fr/1987POIT2297.
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Le pericarpe de la gousse de feve passe d'un stade importateur d'assimilats a l'etat jeune,a un stade exportateur a l'etat senescent, apres une periode de transition. On etudie a chacun de ces stades, l'evolution des 2 composantes de la force proton motrice et leur sensibilite a la pression osmotique du milieu. On etudie aussi les caracteristiques des transports secondaires (absorption de saccharose, et de threonine) energisee par la force proton motrice
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Wäster, Petra. « UVA/B induced redox alterations and apoptosis in human melanocytes / ». Linköping : Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-8880.
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Choi, Adam. « Illuminating Biology with Membrane Penetrating Sulfonate Delivery Scaffolds and Near-Infrared Azasiline Fluorophores ». eScholarship@UMMS, 2018. https://escholarship.umassmed.edu/gsbs_diss/997.
Texte intégralRésumé :
Near-infrared (NIR) light, with wavelengths of 650 to 900 nanometers, effectively penetrates tissues. The high signal to noise ratio and low phototoxicity of NIR light makes this wavelength range ideal for deep tissue imaging. However, current NIR fluorophores are generally large hydrophobic molecules that are prone to aggregation. Sulfonation can enhance aqueous solubility, but their anionic nature prevents membrane diffusion, and thus, restricts the applications of sulfonated molecules to in vitro or fixed cells.
The repertoire of commercially available sulfonated NIR probes is mostly limited cyanines, which have low photostability. Moreover, larger cyanines require multiple sulfonates to maintain aqueous solubility. For example, Indocyanine Green is only sparingly soluble in PBS, despite having two sulfonates.
My work has focused on the delivery of sulfonated dyes into live cells and the development of a new, ultra-compact NIR dye scaffold. First, to expand the in-cell applications of sulfonated fluorophores, I designed reductively-labile sulfonate protecting groups. Using these scaffolds, I have successfully delivered the fluorophore dansyl sulfonate into live cells, where the cytosolic reducing environment unmasks the anionic sulfonate. Secondly, to create a compact, photostable NIR fluorophore, I pioneered the discovery of azasilines dyes. The two azasiline derivatives, ASiFluor710 and ASiFluor730, fluoresce over 700 nanometers and are among the most compact NIR fluorophores currently known. ASiFluor730 also retains the high photostability of oxazine dyes, highlighting their potential in long exposure applications. Beyond the immediate applications in fluorescence microscopy and in vivo imaging, I envision that my work will serve as a framework for the future design of soluble, membrane permeable, NIR fluorescent probes.
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Emani, Sarvani. « THE ROLE OF OUTER MEMBRANE PROTEIN A IN ANAPLASMA MARGINALE CELLULAR INVASION AND ITS POTENTIAL AS A CROSS-PROTECTIVE ANTIGEN ». VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/548.
Texte intégralRésumé :
Anaplasma phagocytophilum and A. marginale are the etiologic agents of human granulocytic anaplasmosis and bovine anaplasmosis, respectively. Both diseases can be severe, even fatal, and protective vaccines for each are lacking. We recently identified A. phagocytophilum outer membrane protein A (ApOmpA) as being critical for cellular invasion and is expressed during infection of mammalian but not tick cells. Disrupting ApOmpA-host cell interactions significantly inhibits A. phagocytophilum entry into host cells. ApOmpA and its A. marginale ortholog, AM854 (A. marginale OmpA; AmOmpA) exhibit 44% amino acid identity. The ApOmpA invasin domain is highly conserved between both proteins. In this study, we investigated the differential expression of AmOmpA in mammalian versus tick cell lines; the serological cross-reactivity between AmOmpA and ApOmpA; the potential role of AmOmpA in mediating interactions with mammalian host cells; and if inhibiting the AmOmpA-host cell interaction impairs A. marginale cellular invasion. AmOmpA is expressed throughout infection of mammalian, but not tick cells. Sera from A. marginale infected cows recognized both AmOmpA and ApOmpA. Sera from cows immunized with an A. marginale OM complex that conferred protection also recognized both proteins. Thus, ApOmpA and AmOmpA share cross-reactive B-cell epitopes. To determine if AmOmpA plays a role in promoting A. marginale infection, we assessed the abilities of recombinant AmOmpA to competitively inhibit infection of mammalian host cells. To examine the cross-reactive properties of OmpA, we showed that preincubation of host cells with GST-ApOmpA and pretreatment of A. marginale with anti-GST-ApOmpA significantly inhibit A. marginale infection of host cells; and that pretreatment of A. phagocytophilum with serum from cows immunized with an A. marginale OM complex reduces its infection of host cells. These studies advance understanding of conservation of OmpA-mediated cellular invasion between Anaplasma species and highlight the potential of OmpA as a vaccinogen that could offer protection against human and veterinary anaplasmoses.
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Gariépy, Yvan. « Pressure regulated silicone membrane gas permeator for long term CA storage of fruits and vegetables ». Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61822.
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Nicolas, Pierre Morgan. « Etude clinique dans la prise en charge du membre supérieur chez l'hémiplégique vasculaire : comparaison de la méthode de Bobath à la technique de protection articulaire ». Montpellier 1, 1998. http://www.theses.fr/1998MON11107.
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Barkallah, Amine. « Membranes et systèmes pour le contrôle des échanges de fluides dans un boîtier électronique : essais et modélisation ». Montpellier 2, 2009. http://www.theses.fr/2009MON20048.
Texte intégralRésumé :
Dans cette thèse l'impact de l'utilisation des membranes de respiration dans les boîtiers protégeant les calculateurs électroniques embarqués dans une automobile a été étudié. Pour cela, une investigation expérimentale et théorique a été développée afin de comprendre l'ensemble des phénomènes de transfert de matière et de chaleur qui contrôlent les différents échanges de fluides en réponse aux changements des conditions environnementales externes et internes aux calculateurs (température, pression, humidité relative et pression partielle de vapeur). Une caractérisation complète des membranes par des techniques statiques et dynamiques a permis de préciser la structure des membranes et ainsi d'obtenir l'ensemble des paramètres structurels et morphologiques nécessaires à la modélisation. Par la suite, un modèle a été développé basé sur une approche de résistances en série en considérant l'influence des couches limites sur le transfert de masse et en couplant les transferts de masse et de chaleur dans l'ensemble. Le modèle a été validé en confrontant les courbes de simulations aux résultats expérimentaux effectués sur un boîtier réel et un boîtier de référence sous différentes conditions opératoires. Des conclusions sur le choix de ces systèmes et de leur dimensionnement ont été définies et les limitations de leurs utilisations ont été identifiées. Un des problèmes rencontrés lors de l'utilisation d'une membrane de respiration a été l'augmentation de l'humidité relative au sein du boîtier. Le modèle développé et validé peut ainsi servir comme outil prédictif et de dimensionnement du système en sa globalitéIn this thesis we studied the impact of the application of breathing membranes on protecting boxes of calculators embarked in a car. For that, a comprehensive experimental and theoretical study was developed in order to understand the whole phenomena of mass and heat of transfer controlling the exchanges of fluids in response to changes of external and internal environmental conditions (temperature, pressure, relative humidity and vapour partial pressure). A complete characterization of the membranes by static and dynamic techniques made it possible to specify the structure of the membranes and thus to obtain full structural and morphological parameters necessary to modelling. Thereafter, a model was developed based on an in series resistances approach by considering the influence of the boundary layers on the global transfer and by coupling mass and heat transfers in the whole system. The model was validated by matching the simulation curves with experimental results carried out with an actual and a reference box under various operating conditions. Conclusions on the choice of these systems and their dimensioning were then defined and the limitations of their uses were identified. One of the problems encountered during the use of a breathing membrane was the increase of relative humidity within the case. The developed and validated model can thus be used as predictive tool and as a sizing tool of the system
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Malak, Arnaud. « Etude du complexe épaule / membre supérieur : lois de comportement en butées et modélisation cinématique ». Lyon, INSA, 2003. http://theses.insa-lyon.fr/publication/2003ISAL0053/these.pdf.
Texte intégralRésumé :
Dans le cadre de la protection des automobilistes, le but de la simulation est d'aboutir à un modèle prédictif des lésions de l'être humain quelle que soit la direction de la sollicitation. La modélisation se heurte à un certain nombre de difficultés liées à un manque de données biomécaniques concernant le complexe épaule / membre supérieur. L'objectif de ce travail était de déterminer des lois de comportement (efforts / déplacements) en butées et de proposer un modèle cinématique pour le complexe épaule / membre supérieur. Un protocole expérimental a été mis au point afin d'extraire des données à partir de sujets d'anatomie. Ce protocole permet une localisation et une reconstitution des repères et marqueurs osseux dans l'espace. L'analyse des données et la méthode d'optimisation ont permis d'estimer les centres de rotation global et scapulo-huméral du complexe épaule / membre supérieur pour les sujets volontaires et anatomiques. Par ailleurs une méthode de mesure des efforts et moments appliqués tant globalement qu'au niveau de l'articulation scapulo-humérale du complexe / épaule membre supérieur a été développé afin d'estimer les butées globales et scapulo-humérale. Enfin, un modèle cinématique du complexe de l'épaule représenté comme un mécanisme comprenant deux chaînes distinctes : une chaîne fermée à 2 degrés de liberté (sternum - clavicule - omoplate - thorax) et une chaîne ouverte à 3 degrés de liberté (thorax - omoplate - humérus) est proposéIn order to create a biomechanical model of the human body for injury prediction, in relation with road users protection, the laws of movements of skeletal parts under passive loading must be known as well as the resistive forces developed by the structure that limit movement amplitude. For the shoulder complex, very few 3D data on mobility are available and most of the work was done on volunteers with external markers. The objective of this work was to collect data on the relative movement of skeletal components of the shoulder complex, on resistive moment of the shoulder joints versus angular movements and to develop a kinematic model of the shoulder complex. A experimental device was develop to collect data with post mortem human subject. The protocol will be used to re-constitute co-ordinate systems and measurement points materialized by metallic implants inserted in the bones. The data analysis and numerical methods was used to estimate global and scapulo-humeral rotation center for voluntary and post mortem subjects. A measurement system for resistive moment of the shoulder joints was develop to estimate limit force. A kinematic model of the shoulder complex corresponds by two mechanism : a closed chain (sternum - clavicula - scapula - torso) with 2 degree of freedom and an open chain (torso - scapula - humerus) with 3 degree of freedom
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Snow, Dallin R. « Dietary Milk Fat Globule Membrane Reduces the Incidence of Aberrant Crypt Foci in Fischer-344 Rats and Provides Protections Against Gastrointestinal Stress in Mice Treated with Lipopolysaccharide ». DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/831.
Texte intégralRésumé :
Milk fat globule membrane surrounds the fat droplets of milk. It is a biopolymer containing primarily membrane glycoproteins and polar lipids which contribute to its properties as a possible neutraceutical. The aims of the studies were to determine if dietary milk fat globule membrane: (1) confers protection against colon carcinogenesis; and (2) promotes gut mucosal integrity while decreasing inflammation compared to diets containing corn oil or anhydrous milk fat.
Aim 1. Three dietary treatments differing only in the fat source were formulated: (1) AIN-76A, corn oil; (2) AIN-76A, anhydrous milk fat; and (3) AIN-76A, 50% milk fat globule membrane, 50% anhydrous milk fat. Each diet was formulated to contain 50 g/kg diet of fat and to be identical in macro and micro nutrient content. To assess protection against colon carcinogenesis, male, weanling Fischer-344 rats were randomly assigned to one of the three dietary treatments. Animals were injected with 1,2-dimethylhydrazine once per week at weeks 3 and 4. After 13 weeks animals were sacrificed, colons were removed, and aberrant crypt foci were counted by microscopy.
Rats fed the milk fat globule membrane diet (n = 16) had significantly fewer aberrant crypt foci (20.9 ± 5.7) compared to rats fed corn oil (n = 17) or anhydrous milk fat (n = 16) diets (31.3 ± 9.5 and 29.8 ± 11.4 respectively; P < 0.05).
Aim 2. Male BALB/c mice were randomly assigned to one of two diets: AIN- 76A, corn oil or AIN-76A, 50% milk fat globule membrane, 50% anhydrous milk fat. After 5 weeks mice were injected with saline vehicle control or lipopolysaccharide and gavaged with dextran-FITC. To assess gut mucosal integrity and inflammation, serum samples were assayed for dextran-FITC 24 and 48 hours after gavage, and a panel of 16 cytokine concentrations was analyzed.
Serum concentrations of IL-6, IL-10, IL-17, MCP-1, IFNγ, and TNFα decreased and gut permeability decreased 45% in lipopolysaccharide challenged mice fed milk fat globule membrane diet compared to control diet at 24 hours (P < 0.05).
Overall, the results of these aims suggest that diets containing milk fat globule membrane are protective against colon carcinogenesis, inhibit the inflammatory response, and protect against gastrointestinal stress.
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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.
Texte intégralRésumé :
Anaplasma phagocytophilum is an obligate intracellular bacterium that infects neutrophils to cause the emerging tick-transmitted disease, human granulocytic anaplasmosis (HGA). Following entry, the pathogen replicates within a host cell-derived vacuole that fails to mature along the endocytic pathway, does not acidify, and does not fuse with lysosomes. Selective fusogenicity is prototypical of many vacuole-adapted pathogens and has been attributed, at least in part, to pathogen modification of the vacuolar inclusion membrane and/or to selective recruitment or exclusion of host trafficking regulators. As a result, the A. phagocytophilum-occupied vacuolar membrane (AVM) provides a unique interface to study the host-pathogen interactions critical to A. phagocytophilum intracellular survival. Diverse vacuole-adapted pathogens; including Chlamydia, Legionella, and Salmonella; selectively recruit host Rab GTPases to their vacuolar membranes to establish replicative permissive niches within their host cells. Rab GTPases coordinate many aspects of endocytic and exocytic cargo delivery. We determined that the A. phagocytophilum-occupied vacuole (ApV) selectively recruits a subset of fluorescently-tagged Rabs that are predominantly associated with recycling endosomes. Another emerging theme among vacuole-adapted pathogens is the ability to hijack ubiquitin machinery to modulate host cellular processes. Mono- and polyubiquitination differentially dictate the subcellular localization, activity, and fate of protein substrates. Monoubiquitination directs membrane traffic from the plasma membrane to the endosome and has been shown to promote autophagy. We show that monoubiquitinated proteins decorate the AVM during infection of promyelocytic HL-60 cells, endothelial RF/6A cells, and to a lesser extent, embryonic tick ISE6 cells. Importantly, tetracycline treatment concomitantly promotes loss of the recycling endosome-associated GFP-Rabs and ubiquitinated proteins and acquisition of the late endosomal marker, Rab7, and lysosomal marker, LAMP-1, implicating bacterial-derived proteins in the ApV's altered fusogenicity. Therefore, we rationalized that A. phagocytophilum-encoded proteins that associate with the AVM may establish interactions with the host cell that are important for intracellular survival. By focusing on A. phagocytophilum proteins that are induced during host infection, we identified the first two bacterial-encoded proteins -- APH_1387 and APH_0032 -- that modify the AVM. Although functional studies are hindered by the lack of a system to genetically manipulate Anaplasma, the pathobiological roles of APH_1387 and APH_0032 are likely unique, as both proteins exhibit very little or no homology with any previously described protein. APH_1387 and APH_0032 are present at the cytoplasmic face of the AVM, therefore they likely interact with host proteins. We demonstrate that ectopic expression of APH_1387 and APH_0032 inhibits the ApV development in A. phagocytophilum infected cells. The results presented in this dissertation contribute to our understanding of how A. phagocytophilum modifies the vacuolar membrane in which it resides to establish a safe haven and evade lysosomal degradation.
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Millerioux, Jennifer. « Formulation et évaluation de la stabilité et de l'efficacité de topiques protecteurs vis-à-vis des composés organophosphorés ». Lyon 1, 2009. http://n2t.net/ark:/47881/m6v40sbv.
Texte intégralRésumé :
Les neurotoxiques organophosphorés (NOP) sont extrêmement toxiques et peu volatils. Dans des conditions normales de température et de pression, ils peuvent pénétrer rapidement la peau sous forme liquide et exercer leurs effets délétères. En milieu civil ou militaire, leur utilisation potentielle est toujours redoutée. Le développement de dispositifs de protection cutanée vis-à-vis de ces agents est donc d’un intérêt majeur pour les armées et la sécurité civile. Dans ce contexte, les objectifs de ce travail ont été de formuler et évaluer la stabilité et l’efficacité de topiques protecteurs cutanés (TP) vis-à-vis des NOP. Le premier objectif a consisté à mettre au point des TP de compositions et de formes galéniques différentes (émulsions, gels) puis à valider leurs stabilités physicochimiques. Cent trente TP ont été formulés et 30 ont montré une stabilité physicochimique satisfaisante. Le second objectif a été d’évaluer l’efficacité des TP les plus prometteurs vis-à-vis des composés organophosphorés. Actuellement il n’existe pas de standardisation de ce type d’étude. Par conséquent, l’utilisation de plusieurs tests in vitro et in vivo (membranes biologiques ou synthétiques, NOP ou simili), dont la pertinence et la fiabilité ont été déterminées, nous a permis d’établir une logique de criblage pour l’évaluation de l’efficacité des TP. Parmi les 13 formulations testées, les résultats ont montré qu’un gel hydro-alcoolique apporte une protection cutanée significative et supérieure aux produits de référence testés vis-à-vis du VX, un NOP d’intérêtPrevention of exposure to the neurotoxic organophosphorus compounds (OP) that are quickly absorbed in the skin is a major concern both for pesticide users and soldiers. Skin barrier creams are being developed to complement or replace uncomfortable chemical protective suits. The objectives of this work were to formulate and assess physicochemical stability and protective efficacy of topical skin protectant (TSP) against OP compounds. The first objective was to formulate several different TSP (emulsions, gel) and validate their physicochemical stability. The second objective was to determine the consistency of results from in vitro tests and the importance of the formulation composition in the skin protective efficacy. Quick evaluation of formulations efficacy mainly relies on in vitro tests which lead to consistent, complementary and relevant results. Our results indicated that the least effective formulations could be quickly identified by performing in vitro permeation tests with silicone membrane and by evaluating interfacial interactions between formulations and OP. We showed that a hydrogel containing specific hydrophilic polymers was by far the most effective of the formulations evaluated against VX, OP compounds, skin permeation in vitro
42
YAMAGUISHI, RENATA B. « Especiação de alumínio em águas subterrâneas na região do manancial Billings : aplicação da radiação ionizante na digestão amostral para fins analíticos e na proposta de remediação ». reponame:Repositório Institucional do IPEN, 2013. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10568.
Texte intégralRésumé :
Made available in DSpace on 2014-10-09T12:42:04Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:04:42Z (GMT). No. of bitstreams: 0
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Benevides, Norma. « Relation entre l'activité herbicide de quelques composés et leur liaison à des protéines ou à des structures membranaires isolées ». Grenoble 1, 1987. http://www.theses.fr/1987GRE10143.
Texte intégralRésumé :
Le travail presente dans ce memoire est une etude des relations pouvant exister entre l'activite de composes herbicides inhibiteurs de la division cellulaire chez les vegetaux et leur liaison a des proteines (tubuline, serum albumine bovine=sab) ou a des structures membranaires (thylakoides). Nous avons constitue une serie d'inhibiteurs connus de la division cellulaire (propyzamide, butraline, pentachlorophenol=pcp, colchicine et deux phenylcarbamates: prophame et chlorprophame=cipc). Nous avons verifie leur efficacite et compare celle-ci a l'activite de 19 pyridilcarbamates nouveaux (. . . )
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Troton, Didier. « Modifications de la composition lipidique des thylakoides intervenant au cours de l'adaptation d'euglena gracilis au diuron ». Paris 7, 1987. http://www.theses.fr/1987PA077169.
Texte intégral
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Wilkinson, Brendan Luke. « Synthesis of Novel Carbohydrate Based Enzyme Inhibitor Libraries Utilising Click Chemistry ». Thesis, Griffith University, 2007. http://hdl.handle.net/10072/366473.
Texte intégralRésumé :
Within a short timeframe, the CuI-catalysed 1,3-dipolar cycloaddition (1,3-DCR) of an organic azide to a terminal acetylene to form a 1,4-disubstituted-1,2,3-triazole, has emerged as a powerful synthetic transformation in combinatorial chemistry, organic synthesis and bioconjugation research. This synthetic methodology, now known as click chemistry, has had an appreciable impact in the drug discovery and biotechnology sectors and has shown broad scope and compatibility with small molecule and polymeric substrates. The application of this powerful synthetic transformation, specifically in carbohydrate based drug discovery and glycobiology is a recent and emerging trend. Chapter one of this thesis is a review of the current literature concerning the use of click chemistry in carbohydrate based drug discovery and glycobiology. Several examples have appeared within the literature highlighting the potential of click chemistry for rapidly generating structurally diverse neoglycoconjugates, ranging from small molecule drug leads to multivalent constructs, as well as a bioconjugation strategy for labelling cell-surface glycoconjugates. The review aims to be exhaustive in its coverage, with emphasis on future perspective. This thesis presents the investigation of click chemistry as a synthetic tool in carbohydrate chemistry, and its application for generating novel carbohydrate based enzyme inhibitor libraries for lead discovery and optimisation purposes. Chapter two describes the utility of click chemistry and the glycosyl triazole moiety in synthetic carbohydrate chemistry. The reaction is well suited to the synthesis of mimetics of complex oligosaccharides and glycoconjugates, owing to the mild ambient nature and remarkable regio- and stereo- selectivity. The transformation was therefore interrogated under conditions typically encountered in carbohydrate chemistry, including glycosylation reactions and protective group manipulations. The study represents the first exhaustive investigation into the stability of the triazole moiety under these conditions as well as the synthetic utility of the CuI-catalysed 1,3-DCR as a potential orthogonal transformation in carbohydrate chemistry and an adjunct to existing methods. The first aspect of the study aimed to examine the stability of the glycosyl triazole moiety under conditions employed in protective group chemistry and the compatibility of the transformation with pre-installed functional groups. Using click chemistry, the triazole moiety could be introduced onto the carbohydrate scaffold in the presence of a wide range of protective functional groups. In addition, the 1,2,3-triazole moiety was indeed shown to be a robust entity that is compatible with essential protecting group manipulations and glycosylation chemistry - an important outcome with respect to its potential utility as an additional tool for the synthesis of oligosaccharide/glycoconjugate mimetics, which are often heavily reliant on orthogonal reaction sequences. Next, the utility of the reaction with respect to solvent and catalyst conditions was examined. The reaction was performed in different organic and aqueous solvents in the presence of two different CuI-catalyst systems. It was shown that the reaction is reasonably insensitive to the nature of the solvent or aqueous co-solvent and the catalyst system. Reaction times and yields displayed little variation with respect to the solvent and catalyst system. In all cases, the 1,4-disubstituted 1,2,3-glycosyl triazole model compound was isolated in high yields and required minimal purification. The work also amply demonstrated, in a proof-of-concept manner, the powerful scope of the reaction for preparing structurally diverse neoglycoconjugates in high yield and purity. Several artificial glycomimetics were prepared using a suite of glycosyl azides through the facile 1,3-DCR to a series of acetylenes. Chapter three presents an extensive study into the preparation and biological activity of glycoconjugate benzene sulfonamides as a novel class of carbonic anhydrase (CA) inhibitor. The conjugation of carbohydrate “tails” to a benzene sulfonamide pharmacophore provides access to CA inhibitors which are neutral, water-soluble and features high chiral density and polyfunctionality that may be exploited for tissue delivery applications and to survey active site architectures in order to impart isozyme selectivity. Glycoconjugate benzene sulfonamides could also display compromised plasma membrane permeability allowing for the selective targeting of tumour associated isozymes with extracellular catalytic domains. Glycoconjugate benzene sulfonamides have received little attention as CA inhibitors, and this work represents the first comprehensive study in the area. By utilising a novel “click-tailing” strategy developed in our laboratory, a panel of structurally diverse carbohydrate “tails” were appended to the primary arylsulfonamide (ArSO2NH2) pharmacophore. A panel of azido sugars and propargyl glycosides were reacted with acetylene- and azide-functionalised benzene sulfonamide scaffolds, respectively, and subsequently evaluated for their inhibition of human carbonic anhydrase (hCA) isozymes hCA I, II, IX, XII and XIV in vitro. In this manner, a total of 50 glycoconjugate benzene sulfonamides belonging to three libraries were prepared and assessed for their inhibition of human cystolic isozymes hCA I, II and transmembrane isozymes hCA IX, XII and XIV. Selective inhibition among CA isozymes is challenging owing to conservation of active site topology within this enzyme family, yet the design of selective CA inhibitors is necessary for the development of efficacious and safe CA-based therapeutics which are void of side effects arising from systemic CA inhibition. Many of the glycoconjugate benzene sulfonamides exhibited a non-clustered in vitro inhibition profile, demonstrating that the carbohydrate tail was a powerful structural element able to distinguish isozyme selectivity. A significant outcome of this study was the discovery of several potent and selective CA inhibitors of the tumour-associated transmembrane isozyme, hCA IX, and the physiologically dominant cytosolic isozyme, hCA II. Chapter four of this thesis explores the synthetic utility of click chemistry for the solution-phase synthesis of N-alkylated azasugar libraries. To date, click chemistry has seen limited application for the synthesis and screening of natural product-based libraries. To the best of my understanding, this work represents the first example of the use of click chemistry for the generation of azasugars containing structurally diverse N-alkyl substituents as potential glycosidase and glycosyltransferase inhibitors. By employing the click chemistry methodology, various synthetically accessible aliphatic and aromatic azides were conjugated to the acetylene-functionalised 6- and 7-membered ring N-propynyl azasugar scaffolds using click chemistry, thus providing expedient access to N-methylene triazole-substituted azasugars in a single, high yielding step. The work demonstrates the applicability of the reaction for generating not only the structural diversity deemed necessary for distinguishing inhibitory potency and selectivity, but also a powerful means of tuning the physicochemical properties of the azasugar for in vivo targeting and lead optimisation purposes.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Physical Sciences
Full Text
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Chuang, Chuan-Chieh, et 莊傳節. « The study of the materials of filter and membrane for military protection ». Thesis, 2005. http://ndltd.ncl.edu.tw/handle/78586358995102874188.
Texte intégralRésumé :
碩士國防大學中正理工學院
應用化學研究所
93
In the study, ASC impregnated activated carbon as an adsorbent of the regenerative filtration systems was estimated. ASC carbons were treated humidification and thermal regeneration by different recycle times, respectively. Several methods included that, Moisture contain measurement, N2 isotherms (BET) measurement, Scanning Electron Micrograph (SEM), Electron Spectroscopy for Chemical Analysis (ESCA), Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimeter (DSC) were employed in this study for analyzed the variations of ASC carbon. On the other hand, the protective performances were contrasted original carbon with 80 ± 6 % for the residual adsorption of hydrogen cyanide of the regenerative carbons. Polyethylenimine (PEI) has nucleophilic amine groups, which can react with electrophilic species such as sulphur mustard and soman. Polyvinyl Alcohol (PVA) is excellent gas barriers. In this study, the blend polymers were prepared for the layers in protective clothing. The variations of different weight ratio of blending membranes were analyzed by FT–IR and DSC. From these results, a further investigation will be carried out in our laboratory to develop the selectively permeable membranes.
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Liang, Junfeng. « Determination properties of guinea pig tympanic membrane using combined fringe protection and simulations ». 2009. http://digital.library.okstate.edu/etd/Liang_okstate_0664M_10547.pdf.
Texte intégral
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Yang, Shu-Yi, et 楊淑怡. « Protection of membrane vesicles against desiccation by three LEA proteins (group Ⅳ ) from soybean ». Thesis, 2003. http://ndltd.ncl.edu.tw/handle/14632350423879181746.
Texte intégralRésumé :
碩士國立臺灣大學
植物學研究所
91
We have examined whether purified group Ⅳ LEA proteins in soybean seeds can maintain the structure of artificial liposome under desiccation in this study. We also studied the relationships between protective effect and phase transition temperature (Tm) of desiccated membrane. All LEA proteins（GmPM01, GmPM16 and GmPM28） were proved to be able to protect various dehydrated liposomes. GmPM16 was more effective in terms of membrane protection than other group IV LEA proteins. The occurrence of GmPM16 on both side of liposome had better effect on structural integrity of dehydrated vesicles than only GmPM16 existing externally. Three oligosaccharides of soybean seed, sucrose, stachyose and raffinose, were more effective than GmPM16 to maintain neutral liposome membrane integrity after desiccation and rehydration. The level of protection observed under the combinations of sugar and protein was close to that observed under only GmPM16 present. The combinations of stachyose and GmPM16 maintained the negative membrane as well as stachyose, and better than only GmPM16. The different combinations of three oligosaccharides and GmPM16 were more effective than either only sugar or protein to maintain the positive liposome above 50 mg protective material / mg of phospholipid. The degree of depression of Tm is correlated with the protective effect of the neutral liposome under dehydration. However, Tm was not correlated with protective effect in the positive and negative liposomes. It may be because that the charge of protein and the vitrification of sugar are also important to maintain the integrity of vesicle under dehydration. In vitro study might help us to hypothesize the mechanism of these LEA proteins in membrane protection in vivo.
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Ting-YuChang et 張庭瑜. « The role of anti-outer membrane protein C antibody in protection from Escherichia coli infection in mouse model ». Thesis, 2014. http://ndltd.ncl.edu.tw/handle/74327715629489345469.
Texte intégralRésumé :
碩士國立成功大學
醫學檢驗生物技術學系
102
Outer membrane protein C (OmpC), one of the major porins located on Gram-negative bacteria, serves as the permeability channel in Escherichia coli to uptake nutrients and antibiotics. The objective of this study is to demonstrate the in vivo evidence to show the protection of anti-OmpC antibody against the infection of OmpC-expressed and OmpC-deficient E. coli. Recombinant OmpC protein combined with Freund’s adjuvant was injected into mice. After five weeks of injection, mice were challenged with OmpC-expressed E. coli and ompC mutant. The results showed that most of the mice without anti-OmpC antibody were died from serious infection, but OmpC-immunized mice had higher survival rate. Nevertheless, the protective efficacy of anti-OmpC antibody against OmpC-expressed E. coli and ompC mutants had no significant differences in the number of survived mice. Both indirect immunofluorescence assay and western blot showed ompC mutant could be recognized by anti-OmpC antibody. Comparing the OmpC amino acid sequence with E. coli whole genome, I found that OmpC has high similarity with other porins including outer membrane protein A (OmpA) and outer membrane phosphoporin protein E (PhoE). Synthesized peptides that specific for OmpC loop region were used to minimize the effect of OmpA and PhoE cross-immunity, but the data showed anti-peptide antibody still had the cross-reactivity with other porins on E. coli. Seven porin mutants of E. coli K-12 strain were constructed, including single, double and triple porin mutation of ompC, ompA, and ompF. SDS-PAGE and western blotting showed anti-OmpC antibody cross-reacted with E. coli K-12 OmpA but not OmpF. In conclusion, these data indicate that by the cross-reactivity of anti-OmpC antibody against OmpA, anti-OmpC antibody protected the mice from the infection of wild-type E. coli and ompC mutant. Therefore, OmpC can be a good vaccine candidate to generate polyclonal antibody for the protection of E. coli infection in the future.
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Mannam, Praveen. « Immune response and protection against Streptococcus pyogenes after vaccination with Lactococcus lactis that expresses conserved region of M6 protein ». Thesis, 2003. http://hdl.handle.net/1957/30816.
Texte intégralRésumé :
Most pathogens gain access to their host through mucosal surfaces. It is
therefore desirable to develop mucosal vaccines that elicit an immune response
to prevent this crucial first step in infection. Current mucosal vaccines are live
attenuated strains of pathogens. More recent efforts have focused on the use of
recombinant non-pathogenic gram-positive bacteria as live vaccine delivery
vectors. Here I have tested the potential of Lactococcus lactis to be used as a
vaccine vector. A recombinant strain of L. lactis has been constructed which
expresses and displays on its surface the C repeat region (CRR) of the M6
protein of Streptococcus pyogenes. I show that nasal vaccination of mice with
this strain elicited strong salivary IgA and serum lgG response. These responses
protected mice against a nasal challenge with S. pyogenes. Subcutaneous
vaccination with the same strain of L. lactis produced a strong serum lgG
response, but no salivary lgA response. Subcutaneous vaccination did not
protect the mice against nasal infections when the mice were challenged with
S. pyogenes. The immune response and protection afforded by concomitant
vaccination by both nasal and subcutaneous routes were better that that seen in
nasal vaccination alone. This study shows that an effective vaccine against
S. pyogenes is possible using L. lactis as a vaccine vector. It also opens up the
potential of L. lactis to be used in the development of vaccines to other mucosal
infections.Graduation date: 2004