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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Cascades physiopathologiques dans la maladie de Sanfilippo B / Pathophysiological cascades of Sanfilippo B disease

Bruyere, Julie 22 October 2012 (has links)
La mucopolysaccharidose de type IIIB (MPSIIIB), ou maladie de Sanfilippo B, est une maladie de surcharge lysosomale caractérisée par des atteintes neurologiques. Cette maladie génétique rare est causée par la déficience en a-N-acétylglucosaminidase (NAGLU), une enzyme nécessaire pour la dégradation des héparanes sulfates (HS). La dégradation incomplète des HS cause l’accumulation de saccharides d’HS dans les lysosomes et à la surface des cellules. Mais la cascade physiopathologique induite par ces saccharides n’est pour l’instant pas connue. D’une part, ces recherches fournissent des preuves que la communication avec l’environnement des cellules neurales déficientes en NAGLU est altérée. En effet, l’intégrine ß1 et ses effecteurs sont suractivés et recrutés au niveau des plaques d’adhérence dans des astrocytes déficients. Les comportements cellulaires dépendants des intégrines, tels que la polarisation et la migration, sont également altérés. Ces phénotypes sont restaurés par l’apport de l’enzyme déficiente. Cette restauration indique que l’accumulation de saccharides d’HS provoque l’activation de la signalisation des intégrines, et perturbe la polarisation et la migration des cellules neurales. L’ajout de saccharides d’HS purifiés sur des cellules neurales normales confirme que les saccharides d’HS extracellulaires activent des composants des plaques d’adhérence. D’autre part, l’étude d’un modèle cellulaire humain, dont l’expression de NAGLU a été inhibée par shRNA, a montré que l’accumulation de vésicules de stockage caractéristiques de la maladie est causée, entre autre, par une déformation de l’appareil de Golgi et la surexpression de GM130. Ces phénotypes sont également observés dans les neurones atteints. Ils s’accompagnent d’une augmentation de la stabilité et de la nucléation des microtubules, au niveau de l’appareil de Golgi. Les défauts de communication entre la cellule malade et son environnement semblent donc modifier la dynamique et la structure cellulaire. Nous présumons que les mécanismes physiopathologiques déchiffrés en culture sont reliés à la neuropathologie de la MPSIIIB. En perturbant la perception de l’environnement cellulaire, la polarité, la migration, et la pousse neuritique, les saccharides d’HS accumulés dans les tissus cérébraux malades, affectent probablement divers mécanismes clefs de la maturation corticale. / Mucopolysaccharidosis type IIIB (Sanfilippo B disease) is a lysosomal storage disease characterized by severe neurological manifestations in children. This rare monogenic disease is caused by a-N­acetylglucosaminidase (NAGLU) deficiency, a lysosomal hydrolase necessary for heparan sulfate (HS) degradation. This deficiency leads to the accumulation of HS saccharides. Mechanisms mediating HS saccharides deleterious effects on brain cells are not well understood. This research provides evidences that neural cell sensing of environment is altered in MPSIIIB cells. Integrins and focal adhesion components are over-recruited and over-activated in deficient mouse astrocytes. Consistently, integrin-dependant cell behavior such as cell polarization and directed migration were defective in affected astrocytes and neural stem cells. HS saccharide clearance, by NAGLU gene transfer, rescues a normal phenotype suggesting that HS saccharides induce focal adhesion formation. Addition of purified HS saccharides on normal astrocytes confirms that extracellular HS saccharides can activate the recruitment of focal adhesion components and provides an in vitro assay to decipher the saccharide code of HS. Otherwise, investigations performed on HeLa cell model, in which NAGLU expression was inhibited by shRNA, showed that accumulation of intracellular storage vesicles, a hallmark of the disease, is due over expression of a cis-Golgi protein. This affects the Golgi morphology and microtubule nucleation and stability. It seems that alterations of environment cell sensing and downstream signaling also modify the dynamic and the structure of cells. We assume that mechanisms deciphered in cell cultures are related to MPSIIIB neuropathology. By affecting cell perception of environmental cues, cell polarity, cell migration and neurite outgrowth, HS saccharides, which accumulate in brain tissues defective for a HS degradation enzyme, likely affect various processes important for accurate cortical maturation.
22

Synthèse d’outils pour le marquage métabolique des glycanes. / Synthesis of tools for the metabolic labeling of glycans.

Carlier, Mathieu 22 November 2019 (has links)
Les glycanes sont des biomolécules constituées d’un enchainement de monosaccharides liés entre eux par des liaisons glycosidiques. La nature et l’abondance des monosaccharides constituant la chaine glycanique ainsi que l’agencement des motifs de glycosylation diffèrent fortement en fonction de l’organisme d’origine. La biosynthèse et la dégradation de ces architectures polysaccharidiques sont finement régulées par des systèmes enzymatiques spécifiques et sont organisées au sein des divers compartiments cellulaires. Les glycanes interviennent dans divers processus biologiques : réserves énergétiques, repliement et stabilité protéique, reconnaissance cellulaire et adhésion à la matrice extracellulaire.Cette thèse porte sur la synthèse et l’utilisation de composés permettant le marquage métabolique des glycanes de cellules eucaryotes (lignée cellulaire du cancer de la prostate, PC-3) ou de bactéries didermes à mycomembranes (Corynebacterium glutamicum).Les composés synthétisés ou utilisés dans cette thèse sont des saccharides fonctionnalisés par un groupement bio-orthogonal (groupements azido, alcyne ou méthylcyclopropène) ou des outils de marquage porteurs simultanément d’un groupement bio-orthogonal complémentaire (groupements cyclooctyne ou tétrazine) et d’une étiquette pouvant être détectée par une macromolécule fonctionnalisée par des fluorophores (D-biotine/stréptavidine ou 2,4-DiNitroPhénol/ anticorps anti-DNP). La solubilité, en milieu aqueux, des outils de marquage est un facteur limitant leur utilisation. Une partie des travaux de cette thèse a consisté à développer des outils de marquage plus solubles en milieu aqueux, par l’ajout d’un motif -sulfo--alanine. Ce motif porte une fonction acide sulfonique qui est déprotonée, à pH physiologique, favorisant ainsi la solubilité en milieu aqueux.L’incorporation métabolique des saccharides fonctionnalisés ainsi que la capacité des outils à marquer les cellules (après incorporation métabolique) est évaluée, sur l’un ou l’autre des modèles biologiques, par analyse en cytométrie en flux ou par microscopie confocale. / Glycans are biomolecules made up of a chain of monosaccharides bound together by glycosidic bonds. The nature and abundance ofmonosaccharides forming the glycanic chain and the arrangement of glycosylation patterns differ greatly depending on the organism of origin. The biosynthesis and degradation of these polysaccharide architectures are finely regulated by specific enzymatic systems and are organized within the various cell compartments. Glycans are used in various biological processes: energy reserves, protein folding and stability, cell recognition and adhesion to the extracellular matrix.This thesis focuses on the synthesis and use of compounds allowing the metabolic labeling of glycans of eukaryotic cells (cell line of prostate cancer, PC-3) or of diderm bacteria with mycomembranes (Corynebacterium glutamicum).The compounds synthesized or used in this thesis are saccharides functionalized by a bio-orthogonal groups (azido, alkyne or methylcyclopropene groups) or labeling tools simultaneously carrying a bio-orthogonal complementary function (cyclooctyne or tetrazine groups) and a label that can be detected by a macromolecule functionalized by fluorophores (D-biotin/streptavidine or 2,4-DiNitroPhenol/ anti-DNP antibodies). The solubility of labeling tools in aqueous media is a limiting factor. Part of the work of this thesis has been to develop more water-soluble labeling tools by adding a -sulfo--alanine pattern. This pattern has a sulfonic acid function, which is deprotonated at physiological pH, thus promoting aqueous solubility.The metabolic uptake of functionalized saccharides and the ability of tools to label cells (after metabolic uptake) are evaluated in either biological model, by flow cytometry analysis or confocal microscopy.
23

Stanovení enzymové aktivity cellobiasy pomocí kapilární elektroforézy / Determination of enzyme activity of cellobiase using capillary electrophoresis

Velvarská, Romana January 2014 (has links)
This thesis deals with optimization of capillary electrophoresis conditions for the separation of unreacted substrate and products (cellobiose, glucose) generated by the enzymatic cleavage of cellotriose with enzyme cellobiase. The optimal separation electrolyte was shown to be a solution containing 30 mmol·dm-3 sodium hydroxide with addition of 1.0 mmol·dm-3 sodium phosphate and 1.0 mmol·dm-3 sodium phosphate dibasic (pH = 12.38). With this separation electrolyte calibration curves and repeatability were measured and the limits of detection and quantification were determined. The relative standard deviations of peak areas ranged up to 6.1 % and they did not exceed 0.2 % for the migration time. Limits of detection were determined in the range from 0.020 to 0.026 mmol·dm-3 and limits of quantification from 0.066 mmol·dm-3 to 0.085 mmol·dm-3 . Subsequently the enzyme reaction was monitored in offline setup. Furthermore, the offline procedure was automated and the relative standard deviation of cellodextrines after 30 minutes of hydrolysis was ranging up to 13.0 % of glucose and cellotriose and 3.0 % cellobiose using this automated method, which makes it suitable for semiquantitative and comparative measurements. The last part of the experiment was to carry out enzymatic reaction in online setup....
24

Elektroforetické separace sacharidů v krátké kapiláře. / Electrophoretic separations of saccharides in short capillary.

Vochyánová, Blanka January 2012 (has links)
A new laboratory system has been developed for rapid electrophoretic separations and determinations of inorganic and organic ions. The instrument employs short fused silica capillary in combination with contactless conductivity detection. The basic functions of the apparatus have been tested using mixture of inorganic ions. It has further been applied to separations of neutral mono- and disaccharides. The model mixture contains five saccharides (sucrose, lactose, glucose, fructose and ribose). The technique developed has been used to determine sucrose, glucose and fructose in high-energy drinks.
25

Využívání a efektivita aktivizačních metod v chemickém vzdělávání / Use and effectiveness of activation methods in chemistry education

Pražienka, Miroslav January 2012 (has links)
CHARLES UNIVERSITY IN PRAGUE - Faculty of Science Department of Teaching and Didactics of Chemistry Albertov 3, 128 40 Praha 2, Czech Republic Use and effectiveness of activation methods in chemistry education Bc. Miroslav Pražienka mprazienka@seznam.cz Executed pedagogical survey reflects the requirements of modern pedagogy and didactics - the teacher should have a new approach to teaching, both from a technical standpoint, both in the methods. At present, preparation of future teachers, but also in lifelong adult education teachers, computers are preferred, modern electronics (and everything associated with them) and such methods, where the pupil is actively involved in teaching and not just a passive "recipient". For the purposes of my thesis was, therefore, a wide range of teaching aids (PowerPoint presentations, worksheets, educational teaching games, demonstration experiments, tests, including methodologies and manuals), through which pupils were taught. Before and after instruction was given them knowledge and skills test, which was then evaluated. They were also sampled pupils from other primary schools and the results were compared. At the beginning of the survey were established two hypotheses (knowledge and skills gradually decreases with increasing time from the subject and taught for a...
26

Vzdělávací projekt Sacharidy Projektová výuka v chemii na gymnáziu / Educational Project Saccharides Topic Work in Chemistry for high school

Šedivá, Renata January 2012 (has links)
Charles University in Prague - Faculty of Science Department of Teaching and Didactics of Chemistry Albertov 3, 128 40 Praha 2, Czech Republic Educational project Saccharides Topic Work in Chemistry for high School Bc. Renata Šedivá sedivarenata@gmail.com This diploma thesis is a suggestion of educational project Saccharides classifiable into education of Chemistry in 3rd year of four-year grammar school. In the first part there is a research of literature sources concerning the issue project education. The Following part is a suggestion of educational project Saccharides, its product are lessons about the topic saccharides, which are designed, prepared and taught by the students. The suggestion of the project contains a timetable of the project, instructions and methodology for individual parts of the project (motivation, preparation of lessons, laboratory works, presentation of lessons, final practice, test and reflection), methodological notes and documentation to the implementation of the project at Grammar school in Dvůr Králové nad Labem.
27

BIOREACTOR SYSTEM DESIGNS FOR LIPASE-CATALYZED SYNTHESIS OF SACCHARIDE- FATTY ACID ESTERS IN SOLVENT-FREE MEDIA

Ye, Ran 01 August 2011 (has links)
As nontoxic biobased surfactants derived from plant oils and cellulose or starch, saccharide-fatty acid esters are widely used in cosmetics, food, and pharmaceutical industries due to their biocompatibility, biodegradability as well as antimicrobial activity. Generally, saccharide-fatty acid esters are synthesized chemically under high pressure, temperature and the presence of alkaline or acid catalysts leading to low-quality products (chemo-degradation of double bonds and oxygenated moieties) and large amounts of byproducts. In contrast, biocatalytic synthesis enhances sustainability: near-ambient pressure and temperature, the absence of toxic, acids and bases catalysts, and improved selectivity of products. For lipase-catalyzed synthesis under nearly anhydrous conditions, the major hurdle to be overcome is the poor miscibility of the acyl donor and acceptor substrates, resulting in slow reaction rates. Although several approaches such as, the employments of organic solvents, complexation agents, and ionic liquids, have been reported in the literature, a robust solution is desperately needed. This study focused on employing immobilized lipases under completely solvent-free conditions to synthesize saccharide-fatty acid esters using the ester products to enhance miscibility. Experimentally, metastable saccharide particles with a diameter of 10-100 micron-sized suspensions of saccharide were formed in oleic acid-rich ester mixtures initially for synthesis of saccharide-fatty acid esters in packed bed bioreactor containing immobilized lipases. Water, a by-product that limits ester yield by promoting hydrolysis, was removed via free evaporation. In this dissertation, a bioreactor system was developed for the eco-friendly solvent-free, immobilized lipase-catalyzed synthesis of biobasaed surfactants utilizing suspensions as reaction medium with 88 wt% in 6 days; the performance of the bioreactor systems developed for Objective 1 was optimized through water concentration control and interval time with 91 wt% in 4.8 days; and to improve design of bioreactor system developed in Objective 1 by in-line filter and derive a mathematical model to describe the production of esters by the bioreactor systems developed. Finally, 84 wt% ester content was achieved in 8.4 days.
28

Fast Dynamic Processes in Solution Studied by NMR Spectroscopy

Šoltésová, Mária January 2013 (has links)
Nuclear magnetic resonance (NMR) spectroscopy is capable to deliver a detailed information about the dynamics on molecular level in a wide range of time scales, especially if accompanied by suitably chosen theoretical tools. In this work, we employed a set of high-resolution NMR techniques to investigate dynamics processes in several weakly interacting molecular systems in solution. Van der Waals interactions play an important role in inclusion complexes of cryptophane-C with chloroform or dichloromethane. The complex formation was thoroughly investigated by means of 1H and 13C NMR experiments along with the quantum-chemical density functional theory (DFT) calculations. We characterized kinetics, thermodynamics, as well as fine details of structural rearrangements of the complex formation. Internal dynamics of oligo- and polysaccharides presents a considerable challenge due to possible coupling of internal and global molecular motions. Two small oligosaccharides were investigated as test cases for a newly developed integrated approach for interpreting the dynamics of the molecules with non-trivial internal flexibility. The approach comprised advanced theoretical tools, including stochastic modeling, molecular dynamics (MD) simulations, and hydrodynamic simulations. A biologically important bacterial O-antigenic polysaccharide from E. Coli O91 was addressed employing selective isotope labeling and multiple-field 13C relaxation experiments. The complex dynamics of the polysaccharide is characterized by the conformational motion of the exocyclic groups of the sugars, superimposed to the breathing motion of the polymeric chain. Hydrogen bonding is another major non-covalent interaction. Dilute solutions of ethanol were chosen as a model of liquid systems containing extensive hydrogen-bonded networks. We developed a new methodology consisting of NMR diffusion measurements, DFT calculations, and hydrodynamic modeling and utilized it to determine average size of the molecular clusters of ethanol at given conditions. / Nukleární magnetická rezonance (NMR) dokáže poskytnout detailní informace o dynamice na molekulární úrovni v širokém oboru časových škál, zejména pokud je doplněna vhodnými teoretickými nástroji. V této práci byla použita sada technik NMR spektroskopie vysokého rozlišení pro výzkum dynamických procesů slabě interagujících molekulárních struktur v roztoku. Van der Waalsovy interakce hrají důležitou roli v inkluzních komplexech kryptofanu-C s chloroformem nebo dichlormethanem. Tvorba komplexu byla podrobně zkoumána za použití 1H a13C NMR experimentů spolu s kvantově-chemickými výpočty. Byla charakterizována kinetika, termodynamika, jakož i detaily strukturních změn při tvorbě komplexu. Vnitřní dynamika oligo- a polysacharidů představuje velkou výzvu  kvůli možnému provázání lokálního a globálního molekulárního pohybu. Dva modelové oligosacharidy byly použity pro testování nově vyvinuté integrované metody pro popis dynamiky molekul s netriviální vnitřní flexibilitou. Tato metoda spojuje pokročilé teoretické výpočty včetně stochastického modelování, simulací molekulové dynamiky a hydrodynamiky. Antigenní bakteriální polysacharid z E. Coli O91, důležitý z biologického hlediska, byl studován za pomoci selektivního izotopového značení a NMR relaxačních experimentů ve více magnetických polích. Komplexní dynamika polysacharidu je charakterizována konformačními změnami exocyklických skupin cukerných reziduí a omezenou interní flexibilitou polymerního řetězce. Vodíkové vazby jsou další z důležitých nekovalentních interakcí. Zředěné roztoky ethanolu byly vybrány jako model kapalného systému obsahujícího rozsáhlou síť vodíkových vazeb. Vyvinuli jsme novou metodologii, složenou z NMR difúzních měření, kvantově-chemických výpočtů a hydrodynamického modelování a aplikovali ji pro zjištění průměrné velikosti molekulových klastrů ethanolu za specifických podmínek. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Accepted. Paper 5: Manuscript.</p>
29

Response of Day 8 Equine Embryos to Saccharide Solutions at Various Temperatures

Foster, Brittany 02 January 2013 (has links)
The response of Day Eight equine embryos to saccharide solutions was investigated as a first step in their potential use as non-permeating cryoprotective agents. Embryos were exposured to seven increasing concentrations of either sucrose or galactose at a temperature of 22°, 30° or 37°C. Each embryo was then rehydrated by exposing it to the same solutions in reverse. Embryos underwent osmotic dehydration, independent of treatment group, but embryo size had a significant effect on the response pattern. Embryos < 500µm dehydrated osmotically to 20% of their original volume. Those > 500µm exhibited a delayed response and only dehydrated to 40% of their original volume. When placed into decreasing concentrations, embryos partially rehydrated. Pre- and post-treatment embryo quality was compared and embryos were stained to determine the amount of apoptosis, with no difference in embryo survival between treatments. Results indicate that saccharides show promise for use in equine embryos < 500µm. / Ontario Veterinary College, Equine Guelph, Partnar Animal Health
30

Rychlé dynamické procesy v roztoku studované pomocí NMR / Fast Dynamic Processes in Solution Studied by NMR

Šoltésová, Mária January 2013 (has links)
Title: Fast Dynamic Processes in Solution Studied by NMR Spectroscopy Author: Mária Šoltésová Department: Department of low temperature physics, Charles University in Prague, and Department of Materials and Environmental Chemistry, Stockholm University Supervisor: doc. RNDr. Jan Lang, Ph.D., Department of low temperature physics, Charles University in Prague, and Prof. Jozef Kowalewski, Department of Materials and Environmental Chemistry, Stockholm University Abstract: Nuclear magnetic resonance (NMR) spectroscopy is capable to deliver a detailed information about the dynamics on molecular level in a wide range of time scales, especially if accompanied by suitably chosen theoretical tools. In this work, we employed a set of high-resolution NMR techniques to investigate dynamics processes in several weakly interacting molecular systems in solution. Van der Waals interactions play an important role in inclusion complexes of crypto- phane-C with chloroform or dichloromethane. The complex formation was thoroughly investigated by means of 1H and 13C NMR experiments along with the quantum- chemical density functional theory (DFT) calculations. We characterized kinetics, thermodynamics, as well as fine details of structural rearrangements of the complex formation. Internal dynamics of oligo- and...

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