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1
Chen, Na. "Synthesis of the N-oxyamide-linked glycolipids and glycopeptides." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLN017/document.
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Les glycoconjugués comme les glycolipides et les glycopeptides sont impliqués dans de nombreux processus biologique, physiologique et pathologique, tels que les interactions cellule-cellule, les infections virales et bactériales, les réponses immunitaires, le cancer, etc. Ces propriétés ont suscité de recherche intensive pour la synthèse de mimes de glycoconjugés pour des applications en biologie et en pharmacie. Cette thèse est consacrée à la synthèse de glycolipides et de glycopeptides liés par la liaison N-oxyamide qui possède une meilleure stabilité métabolique et une facilité de formation de liaison H conduisant à des structures secondaires très intéressantes.Les dérivés de pyranoid glycoaminooxy acides fonctionnés en positions 2 et 6 du sucre sont synthétisés à partir du methyl alpha-D-glucopyranoside, puis transformés en N-oxyamide glycolipides. En tant que nouveaux mimes de glycoglycérolipides et glycosphingolipides, les N-oxyamide beta-glycolipides possédant une ou deux chaines lipidiques sont préparés à partir du glucose ou du galactose penta-acétate et de (S)-1,2-di-O-benzyl-glycérol.De plus, une synthèse stéréosélective de (2R) et de (2S)-3-beta-O-glycosyl aminooxy esters a été réalisée à partir du (2R)-beta-glycoglycérol, avec la réaction de Mitsunobu et l’épimérisation de Lattrell-Dax comme étapes clés. Les N-oxyamide glycopeptides ont pu être préparés à partir de glycosyl aminooxy esters orthogonalement protégésAs part of glycoconjugate family, glycolipids and glycopeptides are involved in a variety of important biological, physiological and pathological processes, such as cell-cell interactions, viral and bacterial infections, immune response, cancer progression, etc. Synthesis of glycoconjugate mimics has attracted intensive research interest for biological and pharmaceutical applications. This thesis was devoted to the synthesis of N-oxyamide-linked glycolipids and glycopeptides, since N-oxyamide-containing compounds have shown improved metabolic stability, and interesting secondary structures due to the easy H-bond formation property of N-oxyamide compounds.From methyl alpha-D-glucopyranoside, the 2,6-functionalized pyranoid glycoaminooxy acid derivatives have been successfully prepared as a multifunctional building block for further derivatization to new N-oxyamide glycolipids. From glucose or galactose pentaacetate and (S)-1,2-di-O-benzyl-glycerol, we have successfully achieved the first synthesis of N-oxyamide-linked beta-glycolipids with one or two lipids chains, as novel mimics of glycoglycerolipids and glycosphingolipids.In addition, the (2R) and (2S)-3-beta-O-glycosyl aminooxy esters have been stereoselectively synthesized from (2R)-beta-glycoglycerol, with Mitsunobu reaction and Lattrell-Dax epimerization as key steps. N-Oxyamide-linked glycopeptides have been prepared from the orthogonally protected glycosyl aminooxy esters
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Oldenburg, Reid. "Immunomodulatory properties of mycobacterial phenolic glycolipids." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCC234/document.
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La biosynthèse de phénol-glycolipides (PGL) par Mycobacterium tuberculosis et M. leprae favorise l’invasion des macrophages via l'interaction de la partie saccharidique des PGL avec le domaine lectine du récepteur cellulaire au complément CR3. Les PGL inhibent également la production de cytokines inflammatoires par la cellule hôte, par un mécanisme inconnu. J’ai observé que des bactéries BCG transgéniques exprimant les PGL de M. tuberculosis ou M. leprae avaient une capacité de survie accrue dans les macrophages. Cette persistance intracellulaire était dépendante de CR3 et associée à une diminution de la production d'oxyde nitrique dans les cellules infectées. L’addition de PGL purifié suffisait à inhiber la production d’oxyde nitrique par des macrophages stimulés avec LPS/IFN-γ. J’ai montré que la liaison de PGL-1 à CR3 provoquait la dégradation post-transcriptionnelle de TIR-domain-containing adapter-inducing interféron-β (TRIF) dans les macrophages, ce qui entraînait une réduction de la signalisation TRIF-dépendante. Dans les macrophages stimulés avec LPS/IFN-γ, la dégradation de TRIF réduisait la production d’oxyde nitrique synthase, et la production TRIF dépendante de cytokines inflammatoires et des chimiokines. Mes résultats ont donc permis d’identifier un nouveau mécanisme de virulence développé par les mycobactéries pathogènes pour réprimer conjointement les réponses inflammatoires et antimicrobiennes de l’hôteBiosynthesis of phenolic glycolipids (PGL) by Mycobacterium tuberculosis and M. leprae promotes macrophage invasion, which proceeds through the interaction of the PGL sugar moieties with the lectin domain of cell-displayed complement receptor (CR3). PGL also limit host cell production of inflammatory cytokines by an unknown mechanism. I observed that transgenic BCG that express PGL specific to M. tuberculosis or M. leprae displayed enhanced survival within macrophages. Increased intracellular persistence of PGL-expressing BCG was CR3-dependent and correlated with the decreased production of nitric oxide in infected cells. Notably, the addition of soluble PGL to macrophages was sufficient to induce a reduction in nitric oxide production upon stimulation with LPS/IFN-γ. I showed that PGL-1 binding to CR3 causes the post-transcriptional degradation of TIR-domain-containing adapter-inducing interferon-β (TRIF) in macrophages, resulting in impaired TRIF-dependent signaling. Functionally, PGL-1-mediated degradation of TRIF resulted in the decreased induction of nitric oxide synthase, and TRIF-dependent inflammatory cytokines and chemokines in LPS/IFN-γ-stimulated macrophages. My results thus identified a virulence mechanism evolved by pathogenic mycobacteria to suppress both the inflammatory and antimicrobial responses of infected host cells
3
Audoin, Coralie. "Valorisation de métabolites secondaires issus de micro-algues : approches métabolomiques, isolement et caractérisation structurale." Thesis, Nice, 2013. http://www.theses.fr/2013NICE4068.
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Les microalgues présentes à la fois dans les eaux douces et salées compteraient plus de 200 000 espèces. Cette diversité en fait une source potentielle de métabolites spécialisés originaux. Parmi les principales familles de substances naturelles valorisées actuellement, on peut citer les pigments, lipides, protéines, polysaccharides, caroténoïdes. Une vision plus globale du métabolome de chacune des espèces apparaît aujourd’hui nécessaire pour mieux mettre en valeur le potentiel commercial que représente cette « microbiodiversité ». Pour cela, nous avons tout d’abord choisi d’approcher le métabolome de différentes souches de microalgues cultivées au sein de la Société Greensea en s’appuyant sur les techniques d’HPTLC, de RMN et d’UHPLC-QTOF pour une visualisation large. Cette étude nous a permis de regrouper les espèces par analogie métabolique après traitement statistique des données. Une seconde partie a consisté en une étude phytochimique approfondie de certaines souches et a conduit à l’isolement et la caractérisation de plusieurs molécules. Ainsi, en plus de métabolites connus, un peptide original portant un motif isoprényl, le cumbriamide a été caractérisé au sein de Lyngbya sp. et une première évaluation de son potentiel thérapeutique a été entreprise. Une large diversité en glycolipides s’est montrée prépondérante dans de nombreuses souches et une méthode de caractérisation a pu être mise au point pour leur identification par UHPLC-QTOF. Enfin, différentes applications des approches métabolomiques ont été envisagées. Ainsi, des études chimiotaxonomiques ont été menées sur les différentes souches de microalgues et l’influence de changements de conditions de culture sur la production de métabolites chez Nannochloropsis oculata a été observéeMicroalgae are present both in Oceans and freshwaters and could include more than 200 000 species. This diversity is a source of original specialized metabolites that can find a large array of applications. Pigments, lipids, proteins, polysaccharides and carotenoids are usual compounds produced by microalgae that have found commercial applications. A global vision of the metabolome of each species has showed promises to highlight the commercial value of this “microdiversity”. We then decided to assess the metabolome of several microalgae species grown at the Greensea company by using HPTLC, NMR and UHPLC-QTOF techniques for a rapid and global overview. A classification of the species according to their metabolomics similarities was obtained after statistics treatment of the data. A second part was dedicated to a phytochemical study of the extracts of selected strains and led to the isolation and characterization of several metabolites. Thus, in addition to known molecules, an original peptide substituted by an isoprenyl moiety and named cumbriamide has been characterized in Lyngbya sp and a first assessment of its therapeutical potential has been undertaken. Glycolipids have been identified as the major metabolites in the extracts of numerous strains and a UHPLC-QTOF method was developed for their identification. Finally, several applications of the metabolomics approaches were considered. Chemotaxonomic studies were first carried out and the influence of growth conditions on the metabolome of Nannochloropsis oculata was observed
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Cobo, Cardenete Isidro Felipe. "Glycolipids: synthesis and multivalent systems." Doctoral thesis, Universitat Rovira i Virgili, 2012. http://hdl.handle.net/10803/284152.
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Els glicolípids i particularment els glicoesfingolípids són compostos d’interès perquè poden interaccionar amb biofactors tot inhibint o interferint en processos fisiològics de les cèl•lules. Per exemple, els glicoesfingolípids que recobreixen les membranes cel•lulars poden interaccionar en processos de reconeixement amb bactèries, virus i toxines com per exemple la toxina del Còlera la qual inicia el procés d’infecció pel reconeixement de glicolípids com el GM1. Tot i que l’ús d’antibiòtics és el tractament més emprat, la resistència als antibiòtics a zones endèmiques fa necessària la recerca en síntesi d’inhibidors basats en derivats de carbohidrats. Donat que la síntesi de compostos glicoconjugats que presenten multivalència ha resultat competitiva en la preparació d’inhibidors contra patògens en aquest treball s’ha estudiat la síntesi de nous mimètics basats en -galactosilceramides; l’acoblament Sukuki-Miyaura en 2-iodoglicals per obtenir nous precursors de carbohidrats i l’anclat de -galactosilceramides en suports com polímers hiperramificats per tal d’avaluar la seva inhibició front la toxina del Còlera.Los glicolípidos y particularmente los glicoesfingolípidos son compuestos de interés porque pueden interaccionar con biofactores inhibiendo o interfiriendo en procesos fisiológicos de las células. Por ejemplo, los glicoesfingolípidos que recubren las membranas celulares pueden interaccionar en procesos de reconocimiento con bacterias, virus y toxinas como por ejemplo la toxina del Cólera la cual inicia el proceso de infección a través del reconocimiento de glicolípidos como el GM1. Aunque el uso de antibióticos es el tratamiento más empleado, la resistencia a los antibióticos en zonas endémicas hace necesaria la investigación en síntesis de inhibidores basados en derivados de carbohidratos. Dado que la síntesis de compuestos glicoconjugados que presentan multivalencia ha resultado competitiva en la preparación de inhibidores contra patógenos, en este trabajo se ha estudiado la síntesis de nuevos miméticos basados en -galactosilceramidas; el acoplamiento Sukuki-Miyaura en 2-yodoglicales para obtener nuevos precursores de carbohidratos y el anclado de -galactosilceramidas en suportes como polímeros hiperramificados con el fin de avaluar su inhibición frente la toxina del Cólera.
Glycolipids such as glycosphingolipids are interesting compounds because they can interact with biofactors by inhibiting or interfering in physiological processes on cells. For instance, the glycolipids which present on cellular membranes can interact with bacteria, virus and toxins. In deed, Cholera toxin starts its infective process once it has recognized glycolipids such as GM1. Although the use of antibiotics is the commonest treatment against this disease, the antibiotic resistance in endemic areas makes the investigation in the synthesis of inhibitors based on carbohydrate derivatives necessary. Due to the synthesis of multivalent glycoconjugated compounds have been competitive in order to prepare inhibitors against these pathogens, in the present work we have studied: the synthesis of new mimetics based on -galactosylceramides; the Suzuki-Miyaura cross coupling in 2-iodoglycals in order to obtain new carbohydrate precursors and the anchoring of -galactosylceramides in scaffolds such as hyperbranched polymers in order to evaluate their inhibition binding against to Cholera toxin
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Calabro, Kevin. "Valorisation dans le domaine de la cosmétique de métabolites produits par microalgues et cyanobactéries." Thesis, Université Côte d'Azur (ComUE), 2016. http://www.theses.fr/2016AZUR4100.
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Les secteurs de la parfumerie et de la cosmétique occupent une place proéminente dans la société moderne. De nombreuses entreprises se positionnent depuis plusieurs années sur les produits cosmétiques à ingrédients naturels. Les plantes, longtemps considérées comme matière première principale pour le domaine de la cosmétique, sont aujourd’hui concurrencées par les microalgues dont la biomasse devient plus facile à obtenir grâce aux avancées en biotechnologie bleue. Ainsi, Cosmo International Ingredients se positionne à travers cette thèse pour élargir son panel de matières premières valorisables dans le domaine de la cosmétique. Dans un premier temps, l’étude phytochimique de microalgues péruviennes a permis d’isoler et identifier une famille majeure de métabolites chez les microalgues : les glycolipides. Une recherche de conditions d’extraction optimale pour cette famille a été effectuée et a permis de proposer une méthodologie verte, spécifique et peu coûteuse. Les cyanobactéries connues pour leur production de métabolites structurellement diversifiés ont été sélectionnées pour la culture suivant des critères spécifiques. Cette approche a permis d’isoler et de caractériser 5 composés à forte valeur ajoutée dont 4 peptides et un alcaloïde. Enfin, un forçage métabolique a été effectué sur Microcystis aeruginosa afin d’optimiser la production des 4 peptides cibles. Il en est ressorti que les paramètres température et intensité lumineuse jouent un rôle important dans la production peptidiqueThe sectors of fragrances and cosmetics play a prominent role in the modern society. During the last decades, several companies have been focusing on nature to provide innovative products. Plants have historically been considered the main raw material in the cosmetic field but, recently, microalgae have been identified as a worthy competitor due to the facility to obtain biomass. Thus, the company Cosmo International Ingredients supported this PhD. thesis to broaden their range of raw materials that can be used for the cosmetic industry. First, the phytochemical study of Peruvian microalgae allowed the isolation of a major family of metabolites: glycolipids. An environmentally-friendly, selective and low-cost method for their extraction from the biomass has been developed. Cyanobacteria known for their production of structurally diverse metabolites have been selected for culture following specific criteria; as a result 5 compounds have been isolated and fully characterized, 4 of which were peptides and one was an indole alkaloid. Finally, to optimize the production of the targeted bioactive peptides, a kinetic study was performed for 3 different temperatures and 3 different light intensities. These parameters were found to play a critical role for the peptide production
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Nilsson, Ulf. "Structural requirements for glycolipid receptors recognized by uropathogenic E. coli synthetic and biological studies with fragments and analogs of globo oligosaccharides /." Lund : Organic Chemistry 2, Lund Institute of technology, University of lund, 1995. http://books.google.com/books?id=EjdsAAAAMAAJ.
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Sather, Paula Joan. "Synthesis of cholesterol based model glycolipids." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29876.
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The synthesis of glycolipids containing a variable length polyethylene glycol spacer group between a glucuronic acid (glu) headgroup and a cholesterol (chol) tail
glu-0CH₂(CH₂OCH₂ )nCH₂O-chol
is described. The homologs (n=2,3,5) were prepared by reaction of an excess of commercially available tri, tetra and hexaethylene glycols with cholesteryl-p-toluene sulfonate. 3-O-(8-hydroxy-3,6-dioxaoctyl) cholest-5-ene (2), 3-O-(ll-hydroxy-3,6,9-trioxaundecyl)cholest-5-ene (3) and 3-O-(17-hydroxy-3,6,9,12,15-pentaoxaheptadecyl)cholest-5-ene (4) were produced, and yields were dependent on the amount of excess used. The headgroup was prepared by esterification and acetylation of glucuronolactone to produce methyl (1, 2, 3, 4-tetra-O-acetyl-β-D-glucopyran)uronate which was then brominated at the anomeric carbon to produce methyl (2, 3, 4-tri-O-acetyl-α-D-glucopyranosyl bromide)uronate (1). The headgroup was coupled to the cholesteroxy oligoethylene glycols by a Koenig Knorr type reaction using freshly prepared silver carbonate as the catalyst. Methyl[3-O-(3,6-dioxaoctyl)cholest-5-en-3β-y1-2,3,4-tri-O-acetyl-β-D-glucopyranosid] uronate (5), Methyl[3-O-(3,6,9-trioxaundecyl) cholest-5-en-3β-yl-2,3,4-tri-0-acetyl-β-D-glucopyranosid] uronate (6), and Methyl[3-O-(3,6,9,12,15-pentaoxaheptadecyl)cholest-5-en-3β-yl-2, 3, 4-tri-O -acetyl-β-D-glucopyranosid] uronate (7) were produced with yields of up to 30%. The removal of the methyl ester and acetate protecting groups on the headgroup was accomplished using NaOH in a mixture of solvents followed by acidification with HCl to produce 3-O-(3,6-dioxaoctyl)cholest-5-en-3β-yl-β-D-glucopyranosiduronic acid (8) and 3-O-(3,6,9-trioxaundecyl)cholest-5-en-3β-yl-β-D-glucopyranosiduronic acid (9).
Octaethylene glycol and dodecaethylene glycol were prepared using a solid supported synthesis. The solid polymer used was a trityl chloride functionalized polystyrene 1% divinyl benzene. Mono protected tetraethylene glycol was prepared and attached to the polymer. The protecting group was removed, and the hydroxy terminal was converted to a mesylate leaving group by reaction with methane sulfonyl chloride. To elongate the chain, the anion of tetraethylene glycol was prepared using sodium hydride in DMF. The tetraethylene glycol bound resin was added, and reaction continued at 120 °C for 24 hours. Cleavage of the resultant product from the polymer support yielded octaethylene glycol. Repetition of the mesylation and elongation steps followed by cleavage yielded dodecaethylene glycol. The oligoethylene glycols were purified by passage through a Fractogel 40S gel permeation column.
Two different protecting groups for the tetraethylene glycol were tried. Trialkyl silyl groups were first attempted, but were abandoned due to reduced reactivity and monitoring difficulties during the deprotection. An acetate protecting group was finally used and deprotection was monitored with infrared spectroscopy.Science, Faculty of
Chemistry, Department of
Graduate
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Norris-Cervetto, Edward. "Glycolipids and multidrug resistance in cancer." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419326.
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Matton, Pascal. "Glycolipides fluorescents et gouttelettes glycosylées." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEE037/document.
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Certains agents pathogènes ou cellules tumorales échappent au système immunitaire parce que les cellules immunitaires ne reconnaissent pas les peptides ou protéines présents à leur surface. Les approches thérapeutiques favorisant la reconnaissance de ces peptides ou protéines faiblement immunogènes sont donc très attractives. Pour ainsi forcer l'activation des cellules présentatrices d'antigènes, plusieurs systèmes ont été décrits, à base de liposomes ou de nanoparticules inorganiques. Nous proposons ici d'utiliser un système à base de gouttelettes d'huile. Les micro ou nanogouttelettes d'huile végétale présentent de nombreux avantages par rapport aux microparticules solides inorganiques. Faites de triglycérides naturels, elles sont biocompatibles et biodégradables tout en étant plus robustes que les liposomes. Ce sont des plates-formes idéales pour construire des assemblages multifonctionnels pour la vectorisation. La première partie du projet traite de la synthèse de glycolipides nécessaires pour avoir une reconnaissance des gouttelettes par les lectines présentes dans le système immunitaire (DC-sign). La seconde partie du projet traite de la fabrication des gouttelettes d’huile fonctionnalisées avec les glycolipides précédemment synthétisés et la mise en évidence de leurs interactions avec des lectinesSome pathogens or tumour cells escape the immune system because the immune cells misrecognize their surface peptides or proteins. Therapeutic approaches, promoting the recognition of these poorly immunogenic peptides or proteins are thus very attractive. The strategy is then to process directly peptides or proteins through cell presentating cells. To this end, some systems have been described, based on liposome or nanoparticles. We propose to use an oil droplet based system. Among the microparticles, vegetal oil microdroplets have numerous advantages over solid microparticles. Made of natural triglycerides, they are biocompatible and biodegradable. They are ideal platforms to build multifunctional assemblies for vectorization. In this project, we aim to design and address lipid (soya oil) droplet to dendritic cells via the lectin DC -sign. The first part deals of the synthesis of glycolipids necessary for the recognition by lectins. The second part presents the fabrication of functionalized oil droplets with previously synthesized glycolipids and their interaction with lectins
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Chambers, Martina Natasha. "Synthesis of cellulosic glycolipids using engineered enzymes." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46032.
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Cellulose, a linear polymer of D-glucose units connected by β-1,4 glycosidic bonds, adopts a highly-ordered crystalline structure in solution. In cellulose I, the dominant form of cellulose in nature, the polymeric chains are aligned in the same direction. Previous attempts to synthesize cellulose I in vitro have resulted in the synthesis of cellulose II, which has the thermodynamically favored anti-parallel orientation of chains. The synthesis of soluble fragments or defined surfaces of cellulose I would enable more detailed study of carbohydrate binding domains and other proteins that interact with cellulose in nature.
The objective of this thesis is to prepare a crystalline surface of cellulose I in a controlled manner through the alignment of cellulolipids. A major focus of this thesis is the synthesis of cellulolipids with a cellohexaosyl head group. Cellohexaose is the shortest cello-oligosaccharide with cellulosic properties, but is consequently insoluble in aqueous solution. To improve the solubility of cellohexaose, the addition of a removable charged functionality was explored: either a terminal sialic acid or a phosphate group at the 6 position of the non-reducing terminal glucose. Abg2F6 glycosynthase from Agrobacterium sp. was used to synthesize β-1,4 linked cello-oligosaccharide fluorides from DP = 2 to DP = 4. These cello-oligosaccharides were modified with a removable charged functionality and utilized as donor substrates by CelB glycosynthase, a mutant of a β-1,4 endoglucanase from Caldicellulosiruptor saccharolyticus. Through the combination of glycosynthase enzymes and charged functionalities, a variety of soluble cellohexaosyl analogs were synthesized.
Lyso-glycosphingolipids were prepared by transferring cello-oligosaccharyl fluorides to D-erythro-C18-sphingosine using EGCase glycosynthase. CelB glycosynthase used charged glycosyl fluoride donors to extend the lyso-glycosphingolipids, yielding soluble cellulolipids. The soluble cellulolipids were aligned along an aqueous:organic interface and the charged functionality was removed. Thus, a surface was prepared that appeared to interact with a carbohydrate binding module functionalized with a fluorescent tag. The soluble cellulolipids were successfully incorporated into a nanodisc, as shown through the incorporation of phosphorylated cellohexaosyl sphingosine. Cleavage of the phosphate using alkaline phosphatase yielded a nanodisc containing cellulolipids.
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Falconer, Robert Andrew. "Lipoamino acid based glycolipids for drug delivery." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392430.
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Röthlisberger, Peter. "Lipoteichoic acid and glycolipids of a novel streptococcus /." [S.l.] : [s.n.], 1995. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=11149.
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Salvadó, Molero Míriam. "Synthetic glycolipids as modulators of carbohydrate-protein interactions." Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/456813.
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El Capítol 1 presenta una descripció general de la glicobiologia així com el rol dels sistemes multivalents en la interacció carbohidrat-proteïna. En el Capítol 2 s’estableixen els objectius generals.
El Capítol 3, fa referencia a la síntesi de glicolípids que presenten modificacions a l’anell de piranosa o a la part de l’aglicona. La avaluació tant d’aquest glicolípids com els seus corresponents sistemes multivalents es va dur a terme front glicosidases.
Es va trobar, que les modificacions tant en l’anell de piranosa com en l’aglicona jugaven un paper important en la inhibició. A més a més, el glicocluster que presenta 4 glicolípids va donar la millor potencia d’inhibició per carbohidrat.
En el Capítol 4 es descriu la síntesi d’estructures multivalent amb dos estructures centrals (polímers hiperramificats i dendrimers) que permeten la presentació dels carbohidrats d’una manera polidispersa o monodispersa. La unió amb una determinada proteïna va ser estudiada emprant les tècniques del DLS i SPR. Interaccions mes fortes en solucions diluïdes de proteïna, es van trobar pel sistemes multivalent polidispersos.
En el Capítol 5 s’explora una estratègia novell pel disseny de inhibidors multivalents basats en nanocapsules. Per trobar com afecta la diferent arquitectura dels glicodendrimers in la unió amb proteïnes, experiments de BLI es van duu a terme per determinar el valor del IC50. La modificació selectiva a proteïna també va ser estudiada per una futura formació de les nanocapsules.
La recerca en el Capítol 6 explora la síntesi de fluorosucres com a reactius en la construcció de fluoroglicoproteïnes. Una estratègia general per accedir a un ampli ventall de fluorosucres, via iodurs de glicosil com intermedis, degut al que son reactius útils per la modificació selectiva de proteïnes es va donar a conèixer.
El Capítol 7 presenta les observacions finals i les conclusions extretes dels resultat obtinguts.El Capítulo 1 presenta una descripción general de la glicobiologia así como el rol de los sistemas multivalentes en la interacción carbohidrato-proteína. En el Capítulo 2 se establecen los objetivos generales. El Capítulo 3, hace referencia a la síntesis de glicolípidos que presentan modificaciones en el anillo de piranosa o en la aglicona. La evaluación tanto de estos glicolípidos como sus correspondientes sistemas multivalentes frente glicosidasas se llevó a cabo. Se encontró, que las modificaciones tanto en el anillo de piranosa como en la algicona jugaban un papel muy importante en la inhibición. A más a más, el glicocluster que presenta 4 glicolipidos dio mejor potencia de inhibición por carbohidrato. En el Capítulo 4 se describe la síntesis de sistemas multivalentes con dos estructuras centrales (polímeros hiperramificados o dendrimeros) que permiten la presentación de los carbohidratos de una manera polidispersa o monodispersa. La unión con una determinada proteína fue estudiada utilizando las técnicas de DLS y SPR. Interacciones mas fuertes en soluciones diluidas de proteína, fueron encontradas para los sistemas multivalentes polidispersos. En el Capítulo 5 se explora una estrategia novel para el diseño de inhibidores multivalentes basados en nanocapsulas. Para encontrar como afecta la diferente arquitectura de los glicodendrimeros en la unión con proteínas, experimentos de BLI fueron llevados a cabo para determinar el valor del IC50. La modificación selectiva a proteína también fue estudiada para una futura formación de las nanocapsulas. En el Capítulo 6 se explora la síntesis de fluoroazúcares como reactivos en la construcción de fluoroglicoproteinas. Una estrategia general para acceder a un amplio abanico de fluoroazúcares, via, ioduros de glicosilo como intermedios, debido a que son reactivos útiles para la modificación selectiva de proteínas se dio a conocer. El Capítulo 7 presenta las observaciones finales i las conclusiones extraídas de los resultados obtenidos.
Chapter 1 contains a general introduction that describes the importance of glycobiology and the role of multivalent systems in the study of carbohydrate-protein interactions. Chapter 2 sets out the general objectives of this thesis. The research in Chapter 3 describes the synthesis of a series of glycolipids that presents modifications either in the pyranose ring or in the aglycone moiety and their evaluation as potent inhibitors, together with multivalent systems that presents glycolipids, against glycosidases. It was found that modifications in the aglycone moiety and in the pyranose ring played important role in potency. Moreover, glycocluster that presents 4 glycolipids monomers gave the best inhibitor potency per sugar. The research in Chapter 4 describes the synthesis of multivalent structures with two different central cores (hyperbranched polymers and dendrimers) that allow the presentation of carbohydrate residues in a polydispers or monodispers manner. Binding was detected using DLS and SPR techniques. Strong interactions in a non-saturated protein concentration, revealed by aggregates formation and binding, were found for polydispers multivalent systems. The research in Chapter 5 explores a novel strategy for the design of multivalent inhibitors based on glycodendriprotein-based nanocapsules. In order to explore how the different glycodendrimer architecture affects the binding properties, BLI experiments were carried out to determine the IC50 of the tested glycodendrimers. The site selective protein modification was also studied for a further glycodendriprotein-based nanocapsules formation. The research in Chapter 6 explores the synthesis of fluorosugar reagents for the construction of well-defined fluoroglycoproteins. A general strategy to access a wide range of fluorosugars, via a glycosyl iodide intermediate, that are useful reagents for chemical-site selective protein glycosylation were disclosed. Chapter 7 presents the final remarks and conclusions extracted from the results obtained in this thesis.
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Minden, Hans Markus von. "Synthesis and mesomorphic properties of glycolipids and neoglycolipids." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=959565434.
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Wikström, Malin. "Synthesis and protein curing abilities of membrane glycolipids." Doctoral thesis, Stockholm University, Department of Biochemistry and Biophysics, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1361.
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There are many types of membrane lipids throughout Nature. Still little is known about synthesizing pathways and how different lipids affect the embedded membrane proteins. The most common lipids are glycolipids since they dominate plant green tissue. Glycolipids also exist in mammal cells as well as in most Gram-positive bacteria. Glycosyltransferases (GTs) catalyze the final enzymatic steps for these glycolipids. In the bacteria Acholeplasma laidlawii and Streptococcus pneumonie and in the plant Arabidopsis thaliana, GTs for mono-/di-glycosyl-diacylglycerol (-DAG) are suggested to be regulated to keep a certain membrane curvature close to a bilayer/nonbilayer phase transition. The monoglycosylDAGs are nonbilayer-prone with small headgroups, hence by themselves they will not form bilayer structures.
Here we have determined the genes encoding the main glycolipids of A. laidlawii and S. pneumonie. We have also shown that these GTs belong to a large enzyme group widely spread in Nature, and that all four enzymes are differently regulated by membrane lipids. The importance of different lipid properties were traced in a lipid mutant of Escherichia coli lacking the major (75 %), nonbilayer-prone/zwitterionic, lipid phosphatidylethanolamine. Introducing the genes for the GTs of A. laidlawii and two analogous genes from A. thaliana yielded new strains containing 50 percent of glyco-DAG lipids. The monoglyco-DAG strains contain significant amounts of nonbilayer-prone lipids while the diglyco-DAG strains contain no such lipids. Comparing these new strains for viability and the state of membrane-associated functions made it possible to connect different functions to certain lipid properties. In summary, a low surface charge density of anionic lipids is important in E.coli membranes, but this fails to be supportive if the diluting species have a too large headgroup. This indicates that a certain magnitude of the curvature stress is crucial for the membrane bilayer in vivo.
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Wikström, Malin. "Synthesis and protein curing abilities of membrane glycolipids /." Stockholm : Department of Biochemistry and Biophysics, Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1361.
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Zeb, Neelofar. "Synthesis and lyotropic phase behaviour of novel glycolipids." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336634.
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Comas, Theodore Christopher. "Glycolipids and markers of normal and neoplastic Macroglia /." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488192447430358.
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Joshi-Navare, K. "Biosynthesis of novel glycolipids: basic and applied aspects." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2013. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2193.
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Sarkar, Debasmita. "Mycobacterial glycolipids : pathways to synthesis and role in virulence." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/1790/.
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Mycobacterial diseases are responsible for numerous deaths worldwide, the major pathogens being Mycobacterium tuberculosis and Mycobacterium leprae. Also, in recent years threats from opportunistic pathogens, such as Mycobacterium marinum and Mycobacterium kansasii have been on the rise. These mycobacteria possess a unique lipid-rich cell wall with an array of mycolic acids and species-specific antigenic glycolipids, like the lipooligosaccharides. Some of these solvent extractable lipids possess immunomodulatory properties and play an important role during infection. Lipooligosaccharides (LOS) are surface exposed, polar, antigenic glycolipids that are present in several mycobacterial species. This study used the opportunistic human pathogens M. marinum and M. kansasii as a model system to unravel the genes involved in the biosynthesis of LOSs in Mycobacterium. Using directed mutagenesis and transposon mutagenesis, mutant strains defective in various parts of the LOS biosynthetic pathway were isolated. Analysis of these strains helped in further delineating the pathway and understanding the role of LOSs in virulence. A part of this thesis focussed on studying mycolic acid processing and transport using Mycobacterium smegmatis as a surrogate system. Mycolic acids are the most distinctive components of the mycobacterial cell wall. While their biosynthesis has been studied in detail, processing and transport across the membrane is not well understood. This study attempted to explore the roles of the two putative type II mycolyltransferases MSMEG3437 and MSMEG5851 in mycolic acid processing. Additionally, the role of M. tuberculosis mmpL11 gene was probed as the Mtb-mmpL11 had been reported to be involved in virulence. A null ii mutant of the M. smegmatis homologue, Ms-mmpL11 (MSMEG0241) was generated and analysed for the above study. Deletion mutant strains of the two putative mycolyltransferase II did not show any phenotype, suggesting that their roles are redundant in vivo. Although the Ms-mmpL gene was found to be non-essential, it was found to be involved in transport of free mycolic acids.
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Mullin, Nicholas Paul. "Characterisation of ligand-binding to a carbohydrate-recognition domain of the macrophage mannose receptor." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320620.
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Wait, Peter Robin. "The role of fast atom bombardment mass spectrometry in the structural determination of microbial glycoconjugates." Thesis, University of Greenwich, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361086.
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Morales, Serna José Antonio. "Synthesis of glycolipids and glycodendritic polymers that bind HIV rgp120." Doctoral thesis, Universitat Rovira i Virgili, 2009. http://hdl.handle.net/10803/386454.
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Several viral envelope glycoprotein oligomers assembled into a viral fusion machine, form a molecular scaffold that brings the viral and target cell membranes into close apposition and allow the subsequent fusion events. The fusion pore formation and its sequential expansion are orchestrated by viral and cellular lipids and proteins. The HIV entry process is understood in some detail at the molecular level. It is coordinated by the HIV envelope glycoprotein complex, a trimer of three gp120 surface glycoproteins, each noncovalently attached to three gp41 ransmembrane glycoprotein subunits.%&/It is know that changes in GSLs expression in target membranes can modulate viral fusion and entry. These studies on structure-function relationship of target membrane GSLs, the gp120-gp41 and the viral receptors suggest that plasma membrane GSLs support HIV-1 entry by stabilizing the intermediate steps in the fusion cascade. These observations, led it to hypothesize that upregulation of GSLs metabolites (such as ceramide) and/or modulation of GSLs, which preferentially partition in the plasma membrane microdomains, could have a significant influence on HIV-1 entry. %&/Based on these findings, in this work has been developed a strategy to synthesize glycodentritic polymers that bind HIV rgp120 and inhibit HIV-1 entry. To reach this goal, first it was carried out the total synthesis of D-erytrho-sphingosine with high enantioselectivity and diasteroselectivity. Then, an efficient protocol of glycosylation of ceramides employing stannyl derivatives as strategy was developed. Finally, water-soluble hyperbranched glycodendritic polymers for the study of carbohydrate interactions were synthesized. These glycoconjugate consists of Boltorn H30 hyperbranched polymers, based on the monomer 2,2-bis(hydroxymethyl)propionic acid, functionalized with naturally occurring -Galceramide. The click chemistry permits functional group tolerance during the derivatization of Boltorn H30. Their ability to bind HIV-1 rgp 120 was demonstrated using surface plasmon resonance (SPR).El proceso de infección por VIH-1 es entendido a nivel molecular como la coordinación de la glicoproteína gp120 del virus con glicoesfingolípidos presentes en las membranas celulares de los organismos infectados. Lo anterior permite plantear la idea de que una regulación en el metabolismo de los glicolípidos presentes en las membranas celulares, pueden influir significativamente en la inhibición de la infección con el VIH-1. A partir de esas observaciones, en el presente trabajo se describe la síntesis de glicopolímeros dendriméricos, los cuales tiene la capacidad de reconocer a la proteína rgp120 del VIH-1 e inhibir la entrada del virus a la célula. La primera meta fue la síntesis asimétrica de D-eritro-esfingosina. Posteriormente se desarrolló un protocolo eficiente para la glicosilación de ceramidas. Finalmente, dos glicopolímeros hiper-ramificados, solubles en agua, fueron sintetizados para estudiar las interacciones proteínas-carbohidrato. La estructura de dicho polímero fue el Boltorn H30, unido con una -galceramida.
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Pierce, Eric John. "Bacterial toxins as probes for membrane glycolipids in mammalian cells." Thesis, University of Leicester, 1985. http://hdl.handle.net/2381/35129.
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Cholera toxin which binds specifically and with high affinity to a glycolipid; ganglioside GM1, has been used as a probe to study glycolipid-protein interactions in the plasma membranes of BALB/c 3T3 mouse fibroblasts and mouse lymphocytes. Evidence is presented that: i) a proportion of cholera toxin bound to GM1 of BALB/c 3T3 cells withstood extraction with Triton X-100 at 0C and remained associated with the cytoskeleton; ii) at 37C, cholera toxin-GM1 complexes were completely extracted with Triton X-100. The resulting complexes existed in a macromolecular form that did not involve other membrane components; iii) antibody-induced capping of GM1-cholera toxin complexes in mouse lymphocytes had characteristics in common with cell surface immunoglobulin- and Con A-capping systems. Immuno- fluorescence studies revealed that in all three systems, capping was accompanied by the redistribution of cytoskeletal components and was inhibited by drugs that inhibit microfilament, but not microtubule, function. These findings suggest that capping in these systems occurs by contractile mechanisms with common features and further suggest that, under certain circumstances, some form of trans-membrane linkage exists between GM1 and the cytoplasm. The role of gangliosides as receptors for tetanus toxin in rat brain membranes was investigated Tris-acetate buffer, pH 6.0 and in a more "physiological" buffer. In agreement with the findings of previous workers, the binding of 125I-labelled tetanus toxin to rat brain membranes in Tris- acetate buffer, pH 6.0 was of high affinity and readily inhibited by gangliosides. The receptors were sensitive to sialidase but less so to heat or protease. In contrast, toxin binding to rat brain membranes in Krebs-Ringer buffer, pH 7.4 involved high and lower affinity components. These receptors were fewer, and markedly sensitive to proteases, heat and sialidase. Binding was not readily inhibited by ganglioside so protein, rather than ganglioside, is likely to represent the high affinity binding site detected in Krebs- Ringer buffer.
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Xiao, X. "Investigations of heterocyst glycolipids from cyanobacteria by chromatography/mass spectrometry." Thesis, Swansea University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636702.
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In this thesis studies of the structures of the heterocyst glycolipids of two species of Cyanobacteria, Anabaena cylindrica and Aphanizomenon flos-aquae have been undertaken to provide a better understanding of Cyanobacteria. Early chapters introduce the Cyanobacterium family and the preparation procedures for the heterocyst glycolipids in our studies. These chapters are separated by an introduction of chromatography and mass spectrometry with emphasis on the techniques used in these studies. The remaining chapters discuss the use of GC/EIMS, GC/CIMS, LC/APCIMS and LC/ESMS, MS/MS for the characterisation of the heterocyst glycolipids in the extracts. The GC/MS techniques used with permethylated, deutero-permethylated and trimethylsilylated derivatives of the intact heterocyst glycolipids (obtained from different bands on TLC from Anabaena cylindrica), methoxime glycolipids, aglycones and methoxime aglycones enabled these compounds to be characterised. Complementary structural information was provided by the GC/EI and GC/CI mass spectra of various derivatives. The LC/ESMS and LC/APCIMS studies proved to be effective in both positive and negative ionisation modes. Six glycolipids including two novel ones were detected from two species by these techniques. Band HG-A was shown to contain 1-(O-α-D-glucopyranosyl)-hexacosanediol, 1-(O-α-D-glucopyranosyl)-octacosanetriol and 1-(O-α-D-glucopyranosyl)-octacosanediol, While the keto-compounds, 1-(O-α-D-glucopyranosyl)-keto-hexacosanol, 1-(O-α-D-glucopyranosyl)-keto-octacosanediol and 1-(O-α-D-glucopyranosyl)-keto-octacosanol were found exist in Band HG-B. Besides, the related isomers were also detected. Additionally two heterocyst glycolipids were identified in Band HG-A from Aphanizomenon flos-aquae. A new band on TLC containing heterocyst glycolipids from Aphanizomenon flos-aquae was found and studied by LC/ESMS and LC/APCIMS. Possible structures were proposed.
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Colvine, James Ronald Lindsay. "Studies on mycobacterial glycolipids and inhibitors of mycolic acid biosynthesis." Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285691.
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Nardan, Denise. "Acid hydrolysis of neutral glycosphingolipids thesis submitted in fulfillment of the degree of Doctorate of Philosophy, Auckland University of Technology, June 2007 /." Click here to access this resource online, 2007. http://repositoryaut.lconz.ac.nz/theses/1389/.
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Griffiths, Susanne Lynn. "An evaluation of the role of gangliosides as the receptors for fibronectin and Escherichia coli heat-labile toxins." Thesis, University of Leicester, 1987. http://hdl.handle.net/2381/35236.
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In an attempt to evaluate the role of gangliosides as receptors for fibronectin, a series of Balb/c 3T3 variant cell lines, with a reduced ability to bind the ganglioside-specific ligand cholera toxin (CT), were examined. Initial characterisation showed that the cell lines displayed a generalised reduction in the synthesis of gangliosides more complex than GM3, but not of cell surface glycoproteins. There was no reduction in the levels of fibronectin found at the surface of the variants as compared with the parental cell line and all were able to spread and form focal contacts on fibronectin-coated substrates. These results suggest that complex glycolipids of the 'ganglio' series are not essential for Balb/c 3T3 cells to interact with fibronectin. The role of gangliosides as receptors for heat-labile toxin of E.coli (H-LT) was investigated using CT as a ganglioside-specific control. Both toxins bound to ganglioside GM1 and to Balb/c 3T3 cell membranes. Binding of 125I-labelled toxins was inhibited by either unlabelled toxin. There was no evidence to suggest that CT or H-LT recognised receptor(s), in Balb/c 3T3 cells, in addition to GM1. In rabbit intestinal brush borders at 0°C, there were more binding sites for H-LT than CT and 125I-H-LT binding could not be inhibited by unlabelled CT. At higher temperatures there was some inhibition of 125I-H-LT binding by CT. In Western blots H-LT recognised proteins co-migrating with the major brush border galacto-proteins. Toxin binding to brush borders from the Wistar strain of rat was similar. One of the 125I-H-LT binding sites may be the sucrase-isomaltase complex, since the toxin bound to brush border fractions enriched for enzyme activity. The data suggest that the major binding sites for H-LT in brush borders are not ganglioside in nature but may be glycoproteins.
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Sava, Georgeta Irina. "Investigations on Enterococcus faecalis glycolipids and their role in bacterial virulence." Lübeck Zentrale Hochschulbibliothek Lübeck, 2010. http://d-nb.info/1002133866/34.
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Patin, Emmanuel Christian Jean-Marie Bernard. "Role of mycobacterial glycolipids in survival of bacteria inside the macrophage." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.590624.
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Drage, Michael Gerald. "Toll-like Receptor 2-Mediated Recognition of Mycobacterial Lipoproteins and Glycolipids." Cleveland, Ohio : Case Western Reserve University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1244231392.
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Thesis (Ph.D.)--Case Western Reserve University, 2009Title from PDF (viewed on 19 August 2009) Department of Pathology Includes abstract Includes bibliographical references Available online via the OhioLINK ETD Center
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Liu, Yang. "Synthesis of Glycolipids and Evaluation of Their NKT Cell Stimulatory Properties." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2293.
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Natural killer T (NKT) cells are a subset of T cells that modify a variety of immune responses. NKT cells recognize glycolipid antigen presented by a molecule called CD1d, a nonclassical antigen-presenting molecule. The best known subset of CD1d-dependent NKT cells expresses an invariant T cell receptor Vα (TCR-α) chain. These are referred to as type I or invariant NKT (iNKT) cells. When stimulated by a glycolipid, NKT cells rapidly release large amounts of cytokines. Cytokines released by NKT cells can induce either Th1 or Th2 responses. Th1 cytokines are effective in regulating bacterial, parasitic, and viral infections. But Th1 responses are also involved in some autoimmune diseases, such as type 1 diabetes, lupus, rheumatoid arthritis, and allergen-induced asthma. Th2 cytokines can attenuate proinflammatory Th1 responses and therefore prevent some autoimmune diseases. Lysosomal processing and CD1d loading is very important in regulating the stimulatory properties of antigens. Analogs of KRN7000, with small molecules appended on C6” position of the galactose portion, do not significantly change stimulation of NKT cells. The question is if the substitution at this position would influence the lysosomal processing. Two sets of mono- and disaccharides with and without substitution at C6” position were prepared and evaluated the NKT cell stimulatory properties. The substitution at the C6” position of the sugar moiety of glycolipids do not significantly impact the stimulatory properties of glycolipids and their processing in lysosome. Small changes at C6” are well tolerated. A double bond in the acyl chain and modification of the C6” functional group helped the glycolipid loading into CD1d and NKT cells stimulation. PBS57 is 100 times more active than KRN 7000 in stimulation of NKT cells responses in vitro and in vivo. This improvement is probably due to increasing solubility and improving binding ability with the CD1d.
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Wonjo, Justyna. "Novel glycolipids in CD1d-mediated immunity : synthesis of new agonists of CD1d." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3551/.
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The glycolipid α-galactosyl ceramide, α-GalCer, has been shown to stimulate the proliferation of murine spleen cells and activate the immune system. Stimulation occurs through binding of the glycolipid to the protein CD1d. Subsequent presentation of the CD1d−glycolipid complex to invariant Natural Killer T cells (iNKT cells) initiates the proliferation of a host of cytokines leading to an immune response The therapeutic potential of α-GalCer is currently being explored; however the induction of both Th1 and Th2 cytokines by this agent is likely to limit its therapeutic application. Significantly, analogues of α-GalCer have been shown to induce iNKT cell-derived cytokines more selectively through a skewed Th1-Th2 response. To date, very few alterations around the amide bond have been explored. To investigate its importance in iNKT cell stimulation, a range of α-GalCer and threitol ceramide (ThrCer) analogues has been synthesised in which the amide functionality in these two leads has been replaced with different carbonyl functional groups. These compounds have been tested for iNKT cell induction and in particular their Th1/Th2 response, which determined their therapeutic potential. Labelled derivatives of α-GalCer and ThrCer have also been designed and synthesised to find application in lipid trafficking studies.
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Jemmett, Philip N. "Towards an understanding of the biological activity of glycolipids : a physicochemical study." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8191/.
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Monolayers composed of N-palmitoyl sphingomyelin (SM) or dipalmitoylphosphatidylcholine (DPPC) have been investigated at the air|water interface. Bilayers of these molecules have also been investigated at the Au(111)|water interface. Monolayer studies revealed differences in molecular area between the two molecules, despite identical headgroups, suggesting the sphingosine backbone of SM allows a more densely packed monolayer structure. Polarisation modulated infrared reflection-absorption spectroscopy studies of the corresponding bilayers revealed that the alkyl chain orientation is comparable in either layer at positive potential but changes at negative potential, concomitantly with changes in solvation. Bilayers of both molecules changed structure once the surface charge density measured with chronocoulometry became negative. Surface pressure-area isotherms, X-ray reflectometry and grazing incidence X-ray diffraction were used to investigate monolayers of glycolipids and their mixtures with DPPC. Unusual monolayer structures were found for single-component glycolipid monolayers. Monolayers composed of DPPC or SM mixed with biologically-relevant glycolipids were also investigated using isotherms. Glycolipid structures were chosen to emulate the structural features of the biologically active and potential drug target N-cerotic α galactosylceramide. Evidence was found for a specific interaction between DPPC and N-palmitoyl α-galactosylceramide but not between DPPC and N-palmitoyl β-galactosylceramide. A specific interaction between either glycolipid and SM was not observed.
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Custer, Jenny Elise. "Phospholipids and Glycolipids of the Oral Bacterium Streptococcus mutans UA159." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1307442038.
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Dubey, P. "Biosynthesis of novel glycolipids (Sophorolipids): exploring the mechanism of assembling and biological properties." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2017. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/5873.
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Kadri, Nabil. "Graines de Pinus SP : caractérisation physico-chimique et activité anticancéreuse." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20143/document.
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Les graines de pin (Pinus halepensis Mill., Pinus pinea L., Pinus pinaster et Pinus canariensis) sont les quatre espèces les plus disponibles dans le bassin méditerranéen. Elles sont très utilisées par les populations Nord-africaines en médecine traditionnelle et en gastronomie où elles agrémentent les plats traditionnels (salades, riz, poissons …etc), car elles sont bien connues pour leur excellent goût salé. Cependant, la composition biochimique, les valeurs nutritionnelles, et les mécanismes d'actions cellulaires et moléculaires via lesquels ces graines exercent leurs effets thérapeutiques restent mal élucidés. Le but de notre travail est d'étudier les propriétés physico-chimiques des graines de quatre espèces de pin et la valeur nutritionnelle et pharmaceutique des fractions lipidiques des graines de Pinus halepensis Mill., en utilisant différentes techniques de séparation et d'analyse telles que (DRX, IRTF, CC, LC/MS, GC, GC/MS et RMN) et en examinant la voie principale impliquée dans le développement du cancer qui est l'angiogenèse via des essais biologiques in vitro sur la prolifération et la migration des cellules endothéliales sur Matrigel et in vivo sur une membrane chorioallantoïdienne (CAM) des œufs de poulet ainsi que leurs toxicités sur des cultures cellulaires (Myélome humain HL60, Adénocarcinome du coulon, humain HCT15, Cellules épithéliales A549 et cellules de mélanomes B16F1). Les résultats de la caractérisation physico-chimiques montrent que les quatre graines sont très riches en métabolites primaires (sucres, protéines, protéines de réserve) et secondaires (Phénols totaux et flavonoïdes) comme elles présentent une importante concentration en oligo-éléments (phosphore, potassium, magnésium, Zinc, fer, cuivre et manganèse). Leurs huiles essentielles sont riches en limonène. Les principaux acides gras insaturés pour les quatre espèces sont l'acide linoléique et l'acide oléique. Les propriétés chimiques et physiques de leurs huiles fixes sont dans la norme de qualité agroalimentaire. Les graines de Pinus halepensis Mill. sont les plus riches en lipides totaux qui atteignent un taux de 36% diversifiés chimiquement avec des lipides apolaires (Lipides neutres) et polaires (Quatre classes de glycolipides et six classes de phospholipides). Ces résultats sont de bons indicateurs de la qualité nutritionnelle des graines de pins et impliquent que les lipides neutres, les glycolipides et les phospholipides des graines de Pinus halepensis Mill. dépourvus de toxicité aux concentrations de 1, 10, 25, 50, 100 et 200µg/ml et ayant une activité cytotoxique à 500 et 1000µg/ml et anti-angiogénique in vitro à des concentrations de 100 et 500µg/ml et in vivo à des concentrations de 1mg /ml et 10 mg/ml peuvent être utilisés dans la prévention des maladies liées à l'angiogenèse et à la lutte contre le cancerThe pine (Pinus halepensis Mill., Pinus pinea L., Pinus pinaster and Pinus canariensis) seeds are the four most available species in the Mediterranean basin. They are widely used by North African populations in traditional medicine and gastronomy where they adorn the traditional dishes (salads, rice, fish ... etc) because they are well known for their excellent taste salty. However, the biochemical composition, nutritional value, and the cellular and molecular mechanisms of action through which these seeds exert their therapeutic effects remain poorly understood. The aim of our study was to investigate the physicochemical properties of pine seed species and nutritional and pharmaceutical value of lipid fractions of Pinus halepensis Mill. Seeds using different separation and analysis techniques such as (XRD, FTIR, CC, LC/MS, GC, GC/MS and NMR) and examining the main pathway involved in the development of cancer which is angiogenesis through biological tests in vitro on the proliferation and migration of endothelial cells on Matrigel and in vivo on a chorioallantoic membrane (CAM) of chicken eggs, thus that their toxicity on healthy cell cultures (human myeloma HL60, Adenocarcinoma of human coulon, HCT15, human epithelial cells, A549 and cells melanoma, B16F1). The results of the physico-chemical characterization showed that four seeds are rich in primary metabolites (sugars, proteins, protein reserves) and secondary (total phenolic and flavonoids) as they have a high concentration of trace elements (phosphorus, potassium, magnesium, zinc, iron, copper and manganese). Their essential oils are rich in limonene. The main unsaturated fatty acids of all species are linoleic acid and oleic acid. The chemical and physical properties of their fixed oils are the in standard food quality. Pinus halepensis Mill. seeds are the richest in total lipids which achieved a rate of 36% chemically diverse with non polar lipids (neutral lipids) and polar lipids (Four classes of glycolipids and six classes of phospholipids). These results are good indicators of the nutritional quality of pine seeds and imply that the neutral lipids, glycolipids and phospholipids of Pinus halepensis Mill. seeds devoid of toxicity at the concentrations of 1, 10, 25, 50, 100 and 200µg/ml and having cytotoxic activity at 500 and 1000µg/ml and anti-angiogenic effect in vitro at the concentrations of 100 and 500 µM and in vivo at the concentrations of 1 mg/ml and 10 mg/ml may be useful in prevention of angiogenesis-related and the fight against cancer diseases
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Ces, Oscar. "The phase behaviour of glycolipids employing a novel high-pressure X-ray beamline." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416049.
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Muindi, K. M. "Cellular lipids and immunity : characterisation of glycolipids binding the antigen presenting molecule CD1." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670089.
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Torres-L{u00F3}pez, Beatriz Virginia. "Affinity purification of blood group A-active glycolipids on immobilized Helix pomatia lectin." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/77851.
Full textAbstract:
Lectin affinity chromatography has proven to be a powerful method to separate oligosaccharides based on their stereochemical structures. This technique has not been used for the separation of glycolipids since mixtures of these compounds form micelles in aqueous solution. Since N-acetylgalactosamine (GalNAc) is commonly found in glycolipids, three GalNAc-specific lectins were selected to develop a lectin affinity chromatographic method for glycolipids. To circumvent the difficulty of working with micelles, the autoradiographic detection of ¹²⁵l-labeled lectins binding to glycolipids on thin-layer chromatograms was used to study the glycolipid-binding specificity of the lectins from Helix pomatia, Wisteria floribunda and Dolichos biflorus. All three lectins detected the Forssman glycolipid which has a terminal GalNAcα1-3 residue. The Helix pomatia and Wisteria floribunda lectins are also bound to glycolipids with GalNAcβ-linked residues. The interactions of these lectins with glycolipid derived, ³H-labeled oligosaccharides were also analyzed by affinity chromatography on agarose-immobilized lectins. Only the immobilized Helix pomatia lectin was able to specifically bind oligosaccharides with α-linked GalNAc residues.
The Helix pomatia lectin was selected to develop an affinity chromatography system for the purification of intact glycolipids having terminal GalNAcα1-3 residues. This technique relies on the ability of the immobilized lectin to bind its oligosaccharide ligands in aqueous solutions of tetrahydrofuran (THF) which inhibits micelle formation and permits the separation of non-specifically bound glycolipids. Forssman glycolipid and a human blood group A-active hexaosylceramide were bound to the Helix pomatia column equilibrated in water/THF (5:95). After applying a step gradient of increasing water content (to 50% water), the specifically bound glycolipids were eluted when GalANc was included in the mobile phase. Using these chromatographic conditions, the Forssman glycolipid from the neutral lipid fraction of sheep erythrocyte stroma and the A-active glycolipids from a total extract of type A human erythrocytes were purified in the Helix pomatia column.
The ability to purify human A-active glycolipids from total lipid extracts in a single chromatographic step with the Helix pomatia column was used to isolate A-active glycolipids present in erythrocytes from donors from a rare blood group B(A). The erythrocytes from B(A) subgroup of blood group B individuals, are weakly hemagglutinated by a murine monoclonal anti-A antibody although these erythrocytes should not express blood group A antigens. The Helix pomatia lectin was used to determine the presence and isolate A-active glycolipids from the neutral lipid fraction of erythrocytes from two blood group B(A) donors. However, A-active glycolipids were absent in the glycolipid extracts from erythrocytes from a third B(A) donor and plasma of all three B(A) donors as well as erythrocytes of blood group B and O donors.
Based on the fact that only glycolipids and oligosaccharides with GalNAcα1-3 residues specifically bind to the Helix pomatia column, this lectin column was used to isolate the 'terminal products' of the biosynthetic pathway of the human blood group A glycolipids and glycopeptides from the human epidermoid carcinoma cell line A-431. The metabolically active A-431 cells were grown in the presence of ³H-labeled monosaccharide precursors and the Helix pomatia column was used to determine and compare the rate of incorporation of labeled precursors in the A-active glycoconjugates from these cells.Ph. D.
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Mahon, Robert Norman III. "Direct Inhibition of CD4+ T-cell Activation by Mycobacterium tuberculosis Cell Wall Glycolipids." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1275668686.
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Long, Xiangtian. "Synthesis and Evaluation of Stimulatory Properties of Glycolipids for Natural Killer T Cells." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/2133.
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Natural killer T cells (NKT cells) are a subset of T cells. They regulate a wide range of diseases including infection, tumor growth, and autoimmune diseases, through recognizing glycolipid antigens in the context of CD1d. An understanding of the scope of glycolipid antigens would facilitate use of this cell type in controlling immune responses. Till today, a lysosomal glycolipid, isoglobotrihexosylceramide (iGb3), is the only natural glycolipid that has been found to be recognized by both human and mouse NKT cells. To elucidate the molecular basis of this specific recognition, iGb3 variants were designed and prepared: i) replacement of the C26 acyl chain with shortened acyl chains; ii) replacement of the distal galactose with glucose and mannose; iii) replacement of the intermediate galactose with glucose; iv) replacement of the proximal glucose with galactose. Among these glycolipids, the iGb3 variants with shortened acyl chains are potent stimulators of NKT cells. The iGb3 variant with intermediate glucose also showed the ability to stimulate NKT cells, but this finding needs to be verified. Our findings support the specific recognition of iGb3 by NKT cells. The search for other natural glycolipid antigens focuses on glycolipids that are isolated from bacteria and parasites. Recently, glycosphingolipids (GSL-1, -3, and -4) isolated from the sphingomonodaceae family of bacteria were characterized. GSL-1 has been shown to be a potent stimulator of NKT cells. Moreover, it has been reported that GSL-4 is a stimulator as well. To verify the structures and stimulatory properties of GSLs, GSL-1 to -4 were prepared and tested for their abilities to stimulate NKT cells. The result that only GSL-1 can stimulate NKT cells suggests that synthesis of these higher order GSLs would be an immune evasion mechanism. Neutral glycosphingolipids from sheep-derived F. hepatica liver flukes, a causative agent of fascioliasis, were isolated and characterized. Their structures are closely related to iGb3. Among these glycolipids, neo-iGb4s could be truncated to iGb3 in the lysosome and thus stimulate NKT cells. To test this hypothesis, these glycosphingolipids were prepared and tested. None of these synthetic glycolipids stimulates NKT cells, which suggests that the secretion of these glycolipids by F. hepatica could be the result of the parasite-immune-evasion mechanism.
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Arcens, Dounia. "Conception de nouveaux monomères glycolipidiques par voie chimio-enzymatique pour la synthèse de polymères amphiphiles et leur auto-assemblage dans l’eau : vers des applications de vectorisation." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0838/document.
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Ces travaux de thèse portent sur la conception par voie chimio-enzymatique de polymères amphiphiles issus de glycolipides, capables de s’auto-assembler en phase aqueuse et susceptibles de répondre à des applications de vectorisation de principes actifs. Après une étude préalable des paramètres influents lors de la synthèse enzymatique, huit monomères glycolipidiques porteurs de fonctions esters vinyliques,méthacrylate ou [alpha]-méthylstyrène ont été synthétisés à partir de dérivés d’huile de ricin et de glucose. Les monomères porteurs d’une fonction ester vinylique comme groupement polymérisable ont été copolymérisés en présence d’acétate de vinyle mais les copolymères ainsi formés n’ont pas montré de capacité à s’autoassembler. Les monomères fonctionnalisés par un groupement méthacrylate, ont été copolymérisés en présence de méthacrylate de méthyle ; trois gammes de copolymères ont ainsi été synthétisées par polymérisation radicalaire, les deux premières selon un mécanisme non contrôlé en présence d’un agent de transfert thiolé ou pas et la troisième selon la méthodologie RAFT. Dans tous les cas, des nanoparticules bien définies et stables pendant plusieurs mois ont été obtenues par auto-assemblage de ces trois gammes de copolymères en phase aqueuse. Le Rouge de Nil a été piégé au sein de ces nanoparticules puis relargué par ajout de chlorure de sodium, laissant entrevoir des applications de stabilisation et de vectorisation de principes actifs pour ces nouveaux copolymèresThe aim of this thesis was the conception of amphiphilic polymers able to self-assembly in water forpotential drug delivery applications, from glycolipidic monomers synthesized by a chemo-enzymatic pathway.After a preliminary study of the influent parameters on glycolipid synthesis via enzymatic catalysis, eightmonomers bearing either vinyl ester, methacrylate or a-methylstyrene groups have been synthesized fromglucose and castor oil derivatives. The vinyl ester-bearing monomers have been copolymerized with vinylacetate. Unfortunately, the resulting copolymers did not show interesting self-assembly properties in water.Three families of copolymers were synthesized from the methacrylate-bearing monomers and methylmethacrylate, either by free radical polymerization in the presence or not of a transfer agent or by reversibleaddition-fragmentation polymerization (RAFT). Well-defined and stablenanoparticles were obtained from allthose copolymers. Nile Red was successfully trapped into those nanoparticles and released by adding sodiumchloride, allowing perspectives as potential drug delivery applications for those new copolymers
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FURUKAWA, KOICHI, KOJI KIKKAWA, TETSUYA OKAJIMA, HISASHI NARIMATSU, AKIRA TOGAYACHI, KIYOSUMI SHIBATA, KEIKO FURUKAWA, et al. "STRONG ANTIBODY REACTION AGAINST GLYCOSPHINGOLIPIDS INJECTED IN LIPOSOMEEMBEDDED FORMS IN β3GN-T5 KNOCKOUT MICE." Nagoya University School of Medicine, 2011. http://hdl.handle.net/2237/15356.
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Dockery, Keith Foorest. "Investigations on Glycolipid Production by Pseudomonas Putida grown on Toluene in Batch and Continuous Culture Conditions." PDXScholar, 1994. https://pdxscholar.library.pdx.edu/open_access_etds/4969.
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Utilization of toluene by Pseudomonas putida as its sole carbon and energy source affects morphology, outer membrane protein composition, and glycolipid production. Two strains of P. putida were found to utilize toluene and to coexist in continuous and batch culture. The two strains were designated translucent and opaque, based upon their readily identifiable coloration when grown on Luria agar. The translucent strain was the dominant strain in continuous culture conditions. The outer membrane proteins of P. putida were separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis. When toluene is the carbon and energy source, the trend in protein composition was towards a general increase in concentration of lower molecular weight proteins (wt). A similar decrease occurred in the concentration of higher molecular weight proteins in the range of 70X104-9X104 mol wt. P. putida produces glycolipids when grown on toluene as a sole carbon and energy source. Three glycolipids have been isolated from chemostat and batch culture spent media, using thin layer chromatography on silica gel GF254· The glycolipids are believed to be previously reported mono- and di-rhamnolipids that function as biosurfactants. The release of glycolipid into the media is believed to function to emulsify toluene, aiding in toluene uptake.
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Milkereit, Götz Eckart. "Investigation of colloidal, biophysical and liquid crystalline properties of synthetic alkyl glycosides and glycolipids." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980736676.
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Gorbea, Carlos M. "Glycolipids in mouse F9 teratocarcinoma cells : some changes associated with retinoic acid-induced differentiation /." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-08142009-040425/.
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Aydt, Alexander Paul, Robin Polt, Alexander Paul Aydt, and Robin Polt. "Creating a C-12 Series of Glycolipids for Use as Micelles in Drug Delivery." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/624907.
Full textAbstract:
Micelles are critically important molecules with a variety of uses. They have historically been
used in the multibillion dollar soap industry. More recently, their efficacy in drug delivery has been
demonstrated (1). Normal oxygen-linked glycosides are susceptible to hydrolysis (2). We are seeking to develop a series of carbon-linked glycolipids of varying chain lengths and functional groups in order to observe trends in their micelle properties, including Critical Micelle Concentration (CMC). Presented here are the C-12 Glycoside series.
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Sava, Georgeta Irina [Verfasser]. "Investigations on Enterococcus faecalis glycolipids and their role in bacterial virulence / Georgeta Irina Sava." Lübeck : Zentrale Hochschulbibliothek Lübeck, 2010. http://d-nb.info/1002133866/34.
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Hibert, Geoffrey. "Glycolipids : from synthesis and self-assembly studies to the design of original bio-based polymers." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0249/document.
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Ces travaux de thèse traitent de l’étude de glycolipides et plus précisément d’esters de trehalose pour la synthèse de nouveaux polymères bio-sourcés. Des monoesters et diesters de trehalose ont ainsi été synthétisés par estérification des alcools primaires du trehalose avec des acides gras selon deux voies de synthèse. La première utilisant un agent de couplage peptidique ne nécessite pas l’utilisation de groupement protecteur pour estérifier sélectivement les alcools primaires. La deuxième est une estérification sélective catalysée par une lipase. L’auto-assemblage des esters de tréhalose a ensuite été étudié. Les monoesters possèdent des propriétés tensio-actives dans l’eau et le trehalose monoeruçate a la capacité de gélifier l’eau. Les diesters, quant à eux sont de bons gélifiants pour les solvants organiques etles huiles végétales. Par conséquent, des gels ont été préparés dans trois huiles végétales, puis leur morphologie et leur propriété rhéologique ont été étudiées. Ensuite, les diesters ont été fonctionnalisé et polymérisés selon différentes stratégies. Ainsi, des polyuréthanes et des poly(hydroxyuréthane)s ont été synthétisés par polycondensation tandis que des glycopolyesters ont été obtenus par polymérisation par métathèse et addition thiol-ène. Finalement,les propriétés d’auto-assemblage de ces polymères ont été étudiées. Ces derniers peuvent former des nanoparticules par la méthode de déplacement de solvantsThe aim of this thesis was to study glycolipids and particularly trehalose esters for the synthesis of new bio-sourced polymers. Trehalose monoesters and diesters were synthesized by two esterification pathways of the primary alcohol of trehalose with different fatty acids. The first synthetic route is a protective group-free esterification using a peptide coupling agent and the second one is a lipase-catalyzed esterification. The self-assembly properties of the trehalose esters were investigated. Trehalose monoesters showed surfactant properties in water and trehalose monoerucate was even able to form gels in water. The trehalose diesters appeared to be good gelators for organic solvent and vegetable oil. Thus, gels in three vegetable oils were prepared and their morphology and rheological properties were studied. Afterwards, trehalose diesters were functionalized and polymerized with different strategies.Thus, polyurethanes and poly(hydroxyurethane)s were obtained by polycondensation where as glyco-polyesters were synthesized by acyclic diene metathesis (ADMET) and thiol-enepolymerization. Finally, the self-assembly properties of these polymers were investigated. The latter were able to form some nanoparticles by solvent displacement method