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91	Untersuchungen zur Rolle des oberen Gastrointestinaltraktes in der Verwertung von Milcholigosacchariden: Verdauung und Transport Gnoth, Mark Jean Marcel 18 May 2001 (has links) Untersuchungen zur Rolle des oberen Gastrointestinaltraktes in der Verwertung von Milcholigosacchariden: Verdauung und Transport. In Bezug auf den Gehalt (5-8 g/l) und des komplexen Musters an auf Lactose basierenden Oligosacchariden ist die humane Milch einzigartig unter den Säugetieren. Bisher ist nur sehr wenig über die Funktion von Frauenmilcholigosacchariden (FMO) bekannt. In dieser Arbeit wurde die Verdaubarkeit von FMO durch Glycosidasen des oberen Gastrointestinaltraktes und eines magenähnlichen pH-Wertes sowie deren Transport untersucht. Während einer 2 h Inkubation von FMO mit humaner Speichelamylase sowie Pankreasamylase des Schweins wurden die Oligosaccharide nicht angegriffen. Auch konnten keine Auswirkungen eines pH von 2,5 auf die Struktur neutraler FMO nachgewiesen werden. Im Gegensatz hierzu führte dieser bei sauren, d.h. sialylierten Komponenten, zu einer minimalen Abspaltung von Sialinsäure. Da isolierte Disaccharidasen aus dem humanen Dünndarm nicht verfügbar waren, wurden Bürstensaummembran-Vesikel (BBMV) aus dem des Schweines verwendet. Während einer 24 h Inkubation von FMO mit BBMV wurden minimale Mengen an nicht fucosylierten und/oder sialylierten Oligosacchariden angegriffen. Hierbei wurden Glucose, Lacto-N-Triose und Lactose freigesetzt. Auf der Grundlage dieser Ergebnisse wurden Transportstudien an Caco-2-Zellen durchgeführt. Dabei zeigte sich, daß nur für neutrale FMO ein gerichteter Flux über das Monolayer vorlag, nicht aber für saure Komponenten. Dieser gerichtete Flux ging bei 15 °C verloren, was auf einen endocytotischen Transport der neutralen Oligosaccharide hindeutet. Der Flux über das Monolayer betrug ca. 2% der apikal angebotenen FMO. Mittels HPLC-MS, unter Verwendung einer Hypercarbsäule, analysierte intrazelluläre Fraktionen zeigten eine gerichtete Aufnahme von neutralen FMO, wohingegen keine sialylierten Oligosaccharide nachweisbar waren. Nach Gabe von Brefeldin A, einem Inhibitor des endocytotischen Transportes, kam es zu einer Anreicherung des intrazellulären Gehaltes an neutralen FMO sowie einer Abnahme des transepithelialen Fluxes, so daß für diese Komponenten ein endocytotischer Transport postuliert werden kann. Die Aufnahme in die Zelle unterlag für Lacto-N-Tetraose einer Sättigung mit einem Km von 1,4 mmol/l und Vmax von 18,5 nm Oligosaccharide Muttermilch Verdauung Glycosidasen Bürstensaummembran-Vesikel Transport LC-MS Brefeldin A Endocytose Caco-2 44.37 - Physiologie 42.15 - Zellbiologie 32 - Biologie 33 - Medizin ddc:570 ddc:610
92	Thio-arylglyocosides with Various Aglycon Para-Substituents, a Useful Tool for Mechanistic Investigation of Chemical Glycosylations Li, Xiaoning 12 September 2007 (has links) No description available. Chemistry, Organic Glycosylation Oligosaccharide Rate Determining Step Relative Reactivity Value HPLC Competitive Assay Hammett Plot Thioglycoside NIS DMTST Reactivity-based glycosylation.
93	PROPRIEDADES FÍSICO-QUÍMICAS E EFEITO PREBIÓTICO DE PECTINA HIDROLISADA OBTIDA DE RESÍDUOS AGROINDUSTRIAIS / PHYSICOCHEMICAL PROPERTIES AND PREBIOTIC EFFECT OF PECTIN HYDROLYSED FROM AGRO-INDUSTRIAL WASTE Moura, Fernanda Aline de 13 March 2016 (has links) Pectin is a soluble dietary fiber that in addition to its role in the food industry as a thickener and emulsifier, provides metabolic effects related to weight control, lipids and glucose levels. It is found in significant amounts in agro-industrial residues such as bark and fruit cake. Soybean hulls, a product derived from the bran extraction and legume oil, also has a large amount of pectin in its composition. However, sources of different characteristics tend to provide pectins with monomeric organization and differentiated properties, which determine its technological application and metabolic role. Moreover, studies have indicated that the products of its hydrolysis, in particular pectic oligosaccharides have bifidogenic characteristics are considered as a new class of prebiotics. However, changes in physical and chemical properties caused by hydrolysis and its metabolic effects are not well studied. The optimal amounts of pectic prebiotics consumption also require further evidence to be established. Therefore, the aim of this study was to select promising raw material for efficient extraction and hydrolysis of pectin, evaluating the resulting product (partially hydrolyzed pectin) and the physical and chemical properties and prebiotic potential in vivo. The agro-industrial waste used were soybean hulls, passion fruit peel and orange peel. The passion fruit peel was the raw material with the greatest potential for pectin extraction by presenting yield ( 15.71 %) and galacturonic acid content ( 51.3 % ) , similar to orange peel ( 17.96 % yield and 60.45 % of galacturonic acid) in pectic concentrate, but with residual levels of protein and lipids reduced. Although high pectin content in its composition , the yield of extraction of the polysaccharide was only 5.66 % for soybean hulls . Therefore, passion fruit peel was chosen for pectit prebiotics production. Acid hydrolysis was efficient for two hours to produce changes in molecular weight distribution profile of passion fruit peel pectin, increasing the amount of low molecular weight compounds. The physico-chemical properties form also altered by hydrolysis, with decreased water holding capacity and the copper connection, and increased capacity for absorbing fat. The addition of 0.25% of partially hydrolyzed passion fruit peel pectin provided prebiotic effect, resulting in increased production of short chain fatty acids in growth in rat cecum. / A pectina é uma fibra alimentar solúvel que, além de seu papel na indústria de alimentos como espessante e emulsificante, proporciona efeitos metabólicos relacionados ao controle do peso, perfil lipídico e glicêmico. É encontrada em quantidades significativas em resíduos da agroindústria, como cascas e bagaços de frutas. A casca de soja, um produto resultante da extração do farelo e do óleo da leguminosa, também possui grande quantidade de pectina em sua composição. Todavia, fontes de características diferentes tendem a fornecer pectinas com organização monomérica e propriedades diferenciadas, as quais determinam sua aplicação tecnológica e papel metabólico. Além disso, estudos têm apontado que os produtos da sua hidrólise, em especial os oligossacarídeos pécticos, apresentam características bifidogênicas, sendo considerados uma nova classe de prebióticos. No entanto, as alterações nas propriedades físico-químicas causadas pela hidrólise e seus efeitos metabólicos são pouco estudadas. As quantidades ideais de consumo de prebióticos pécticos também carecem de maiores evidências para serem estabelecidas. Portanto, o objetivo deste estudo foi selecionar matéria-prima promissora para eficiente extração e hidrólise de pectinas, avaliando o produto resultante (pectina parcialmente hidrolisada) quanto às propriedades físico-químicas e potencial prebiótico in vivo. Os resíduos agroindustriais utilizados foram casca de soja, casca de maracujá e bagaço de laranja. A casca de maracujá foi a matéria-prima de maior potencial para extração de pectinas por apresentar rendimento (15,71%) e teor de ácido galacturônico (51,3%), semelhante ao bagaço de laranja (17,96% de rendimento e 60,45% de ácido galacturônico) no concentrado péctico, porém com teores residuais de proteína e lipídeos reduzidos. Embora com elevado teor de pectina em sua composição, o rendimento de extração deste polissacarídeo foi de apenas 5,66% para a casca de soja. Portanto, a casca de maracujá foi escolhida para a produção dos prebióticos pécticos. A hidrólise ácida por duas horas foi eficiente para produzir alterações no perfil de distribuição de massa molar da pectina de casca de maracujá, aumentando a quantidade de compostos de baixa massa molar. As propriedades físico-químicas também foram alteradas pela hidrólise, com diminuição da capacidade de retenção de água e de ligação a cobre, e aumento da capacidade de absorção de gordura. A adição de 0,25% de pectina de casca de maracujá parcialmente hidrolisada proporcionou efeito prebiótico, confirmado pela maior produção de ácidos graxos de cadeia curta no ceco de ratos em crescimento. Casca de maracujá Bagaço de laranja Casca de soja Oligossacarídeos pécticos Ácidos graxos de cadeia curta Passion fruit peel Orange bagasse Soy hull Pectic oligosaccharide Short chain fatty acid
94	Congenital Disorders of Glycosylation IIj (CDG-IIj): Identifizierung eines Defekts der COG6-Untereinheit des Conserved Oligomeric Golgi-Komplexes / Congenital Disorders of Glycosylation IIj (CDG-IIj): identification of a defect in COG6 subunit of conserved oligomeric Golgi complex Lübbehusen, Jürgen 23 April 2009 (has links) No description available. 570 Biowissenschaften, Biologie Mathematics and Computer Science Proteinglykosylierung Conserved Oligomeric Golgi COG Congenital Disorders of Glycosylation CDG protein glycosylation conserved oligomeric Golgi COG Congenital Disorders of Glycosylation CDG 42.15 42.13 35.70 35.77 SX 000: Biochemie SXJ 300: Oligosaccharide {Biochemie} WH 000: Cytologie {Biologie}
95	Structure-Function Relationship Of Winged Bean (Psophocarpus Tetragonolobus) Basic Agglutinin (WBA I ) : Carbohydrate Binding, Domain Structure And Amino Acid Sequence Analysis Puri, Kamal Deep 03 1900 (has links) (PDF) No description available. Winged Beans Amino Acid - Lectin Winged Bean Agglutinin (WBA I) Winged Bean Agglutinin - Sugar Binding Winged Bean Agglutinin - Structure Lectins Winged Bean Agglutinin - Ligand Binding Oligosaccharide Binding Titration Calorimetry Differential Scanning Calorimetry WBAI Plant Biochemistry
96	Zur Bedeutung von Saccharose-Transportern in Pflanzen mit offener Phloemanatomie / On the significance of sucrose transporters in plants with an open phloem anatomy Knop, Christian 01 November 2001 (has links) No description available. 570 Biowissenschaften, Biologie Mathematics and Computer Science Phloembeladung Saccharose-Transporter Symplast Apoplast Aphiden-Technik Phloemsaft Raffinose-Oligosaccharide <i>Alonsoa</i> <i>Asarina</i> Phloem loading Sucrose transporter Symplast Apoplast Aphid-technique Phloem sap Raffinose oligosaccharides <i>Alonsoa</i> <i>Asarina</i> 42.13 42.41 35.70
97	Structural Investigation of Processing α-Glucosidase I from Saccharomyces cerevisiae Barker, Megan 20 August 2012 (has links) N-glycosylation is the most common eukaryotic post-translational modification, impacting on protein stability, folding, and protein-protein interactions. More broadly, N-glycans play biological roles in reaction kinetics modulation, intracellular protein trafficking, and cell-cell communications. The machinery responsible for the initial stages of N-glycan assembly and processing is found on the membrane of the endoplasmic reticulum. Following N-glycan transfer to a nascent glycoprotein, the enzyme Processing α-Glucosidase I (GluI) catalyzes the selective removal of the terminal glucose residue. GluI is a highly substrate-specific enzyme, requiring a minimum glucotriose for catalysis; this glycan is uniquely found in biology in this pathway. The structural basis of the high substrate selectivity and the details of the mechanism of hydrolysis of this reaction have not been characterized. Understanding the structural foundation of this unique relationship forms the major aim of this work. To approach this goal, the S. cerevisiae homolog soluble protein, Cwht1p, was investigated. Cwht1p was expressed and purified in the methyltrophic yeast P. pastoris, improving protein yield to be sufficient for crystallization screens. From Cwht1p crystals, the structure was solved using mercury SAD phasing at a resolution of 2 Å, and two catalytic residues were proposed based upon structural similarity with characterized enzymes. Subsequently, computational methods using a glucotriose ligand were applied to predict the mode of substrate binding. From these results, a proposed model of substrate binding has been formulated, which may be conserved in eukaryotic GluI homologs. Biomolecular structure Eukaryotic glycosylation glycosylation N-glycan N-linked glycosylation Carbohydrate biochemistry Inhibitor antiviral therapeutic Structure-based drug design glucosidase glycosidase glycoside hydrolase post-translational modification enzyme enzyme mechanism inverting mechanism structural biology protein structure 6xHis tag Crystal packing sugar substrate X-ray crystallography single anomalous dispersion PHENIX heavy-atom phasing docking autodock autodock vina biophysical methods tryptophan fluorescence glucose oxidase activity assay enzyme inhibition Protein expression Protein purification Pichia pastoris Saccharomyces cerevisiae fondue AOX1 promoter glycoside hydrolysis substrate binding model molecular dynamics molecular dynamics Binding site Active site cleft Endoplasmic reticulum Glycan processing Glycan trimming protein-protein interactions cell-cell communication X-ray diffraction crystallization secreted protein substrate selectivity kojibiose glucotriose miglitol deoxynojirimycin Glc3Man9GlcNAc2 free oligosaccharide species GluI Cwh41 Cwh41p Cwht1p 0306 0307 0760
98	Structural Investigation of Processing α-Glucosidase I from Saccharomyces cerevisiae Barker, Megan 20 August 2012 (has links) N-glycosylation is the most common eukaryotic post-translational modification, impacting on protein stability, folding, and protein-protein interactions. More broadly, N-glycans play biological roles in reaction kinetics modulation, intracellular protein trafficking, and cell-cell communications. The machinery responsible for the initial stages of N-glycan assembly and processing is found on the membrane of the endoplasmic reticulum. Following N-glycan transfer to a nascent glycoprotein, the enzyme Processing α-Glucosidase I (GluI) catalyzes the selective removal of the terminal glucose residue. GluI is a highly substrate-specific enzyme, requiring a minimum glucotriose for catalysis; this glycan is uniquely found in biology in this pathway. The structural basis of the high substrate selectivity and the details of the mechanism of hydrolysis of this reaction have not been characterized. Understanding the structural foundation of this unique relationship forms the major aim of this work. To approach this goal, the S. cerevisiae homolog soluble protein, Cwht1p, was investigated. Cwht1p was expressed and purified in the methyltrophic yeast P. pastoris, improving protein yield to be sufficient for crystallization screens. From Cwht1p crystals, the structure was solved using mercury SAD phasing at a resolution of 2 Å, and two catalytic residues were proposed based upon structural similarity with characterized enzymes. Subsequently, computational methods using a glucotriose ligand were applied to predict the mode of substrate binding. From these results, a proposed model of substrate binding has been formulated, which may be conserved in eukaryotic GluI homologs. Biomolecular structure Eukaryotic glycosylation glycosylation N-glycan N-linked glycosylation Carbohydrate biochemistry Inhibitor antiviral therapeutic Structure-based drug design glucosidase glycosidase glycoside hydrolase post-translational modification enzyme enzyme mechanism inverting mechanism structural biology protein structure 6xHis tag Crystal packing sugar substrate X-ray crystallography single anomalous dispersion PHENIX heavy-atom phasing docking autodock autodock vina biophysical methods tryptophan fluorescence glucose oxidase activity assay enzyme inhibition Protein expression Protein purification Pichia pastoris Saccharomyces cerevisiae fondue AOX1 promoter glycoside hydrolysis substrate binding model molecular dynamics molecular dynamics Binding site Active site cleft Endoplasmic reticulum Glycan processing Glycan trimming protein-protein interactions cell-cell communication X-ray diffraction crystallization secreted protein substrate selectivity kojibiose glucotriose miglitol deoxynojirimycin Glc3Man9GlcNAc2 free oligosaccharide species GluI Cwh41 Cwh41p Cwht1p 0306 0307 0760

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