Breast milk remains the optimum vehicle to deliver high quality nutrients, including oligosaccharides, in quantities sufficient to sustain normal growth, however, it is currently unknown whether the addition of prebiotics to infant formula would alter neonate growth and development. The objective of this study was to determine the effect of Galactooligosaccharides (GOS) and Fructooligosaccharides (FOS) supplementation in nursery pig diets on growth and efficiency of food utilization. Forty-eight 4-day old crossbred pigs (1.628 ± .037 Kg BW) were randomly assigned to 1 of 8 diets: 1) milk-based formula containing Type 2 GOS and Type 1 FOS (4 + 1 g/L); 2) soy-based formula containing Type 1 FOS (3g/L); 3) milk-based formula with no prebiotic added; 4) milk-based formula containing Type 2 GOS only (5g/L); 5) milk-based formula containing Type 1 GOS only (5g/L); 6) milk-based formula containing Type 2 GOS and Type 2 FOS (4 + 1 g/L); 7) milk-based formula containing Type 1 GOS and Type 1 FOS (4 + 1 g/L); 8) soy-based formula with no prebiotic added. Diets were isonitrogenous, isocaloric and fed at 250 mL/kg body for a 2-week period. At sacrifice, blood and tissue samples were collected for analysis. A diet by time interaction (P < 0.001) indicated a smaller rate of accretion in bone mineral content for soy-based diets. Total bacteria and lactobacillus were significantly affected by treatment (P < 0.001). In conclusion, the addition of GOS and FOS to formula does not appear to alter growth however, the gut microbiota was significantly modified. / Master of Science

Thesis (M.S.)--University of Michigan, 1980.

Thesis (M.S.)--University of Michigan, 1980.

L’arthrose est la plus fréquente des maladies articulaires pour laquelle aucun traitement efficace n’est aujourd’hui disponible. Elle est caractérisée par une destruction du cartilage et de ses composants, dont font partie les protéoglycanes. Les principaux protéoglycanes cartilagineux sont les sulfates de chondroïtines, qui sont de longs polysaccharides linéaires hétérogènes composés d’unités disaccharidiques répétitives constituées d’un acide-D-glucuronique et d’une N-acétyl-D-galactosamine. Dans le but d’étudier la biosynthèse de ces composés et ainsi de mieux comprendre le mécanisme d’action des enzymes qui y sont impliquées, la synthèse chimique d’oligosaccharides de chondroïtines et de sulfates de chondroïtines biotinylés a été réalisée. Grâce à une méthodologie efficace et innovante basée sur une hydrolyse acide d’un polymère de sulfates de chondroïtines, des intermédiaires clés ont rapidement été obtenus. Une stratégie d’élongation les utilisant a ensuite été appliquée pour conduire à une première famille de sept oligosaccharides non sulfatés (du disaccharide à l’octasaccharide). Deux nouvelles familles d’oligosaccharides de sulfates de chondroïtines A et C, sulfatés de façon homogène ont été préparées, à partir d’un précurseur commun par stratégie divergente. Pour la première fois, deux oligosaccharides de sulfate de chondroïtine A, présentant une sulfatation hétérogène, ont également été synthétisés. Ces travaux ont mené à la préparation de treize oligosaccharides biotinylés finaux. / Osteoarthritis is the most frequent articular disease but until now no treatment exists. It is characterized by a destruction of cartilage and its components as proteoglycans. Major cartilage’s proteoglycans are chondroitin sulfate, which are linear and heterogeneous polysaccharides composed of disaccharidic repeating units constituted of a D-glucuronic acid and an N-acetyl-D-galactosamine. In order to study biosynthesis of those compounds and so to better understand working mechanism of the implicated enzymes, chemical syntheses of biotinylated chondroitin and chondroitin sulfate oligomers have been achieved. Thanks to an efficient hydrolysis of a starting chondroitin sulfate polymer, key building blocks were quickly obtained. An elongation strategy using them has been then applied to give a first family of seven non sulfated oligosaccharides (from disaccharide to octasaccharide). Two new families of chondroitin sulfate A and C oligosaccharides, with homogeneous sulfation have been prepared from a common precursor by divergent strategy. For the first time, two chondroitin sulfate A oligosaccharides with an heterogeneous sulfation have been synthetized. This work has led to thirteen final biotinylated oligosaccharides.

L'objectif principal de ce travail est la préparation de nanoparticules d'argent (AgNPs) stabilisées par des oligo-et polysaccharides et leur application en catalyse et pour la détection de lectines. Pour atteindre cet objectif, deux stratégies ont été utilisées, l'une utilisant le polysaccharide dextran comme stabilisant et l'autre utilisant des composés amphiphiles oligosaccharidiques dérivés du maltose, lactose, maltoheptaose et du xyloglucane. Dans les deux stratégies, la préparation des nanoparticules AgNPs a été optimisée en réalisant une analyse multifactorielle basée sur l'étude de la bande de résonance plasmonique de surface (SPR) des nanoparticules. Toutes les suspensions colloïdales stables de nanoparticules ont été caractérisées par spectroscopie ultraviolet-visible (UV-vis), microscopie électronique à transmission (TEM), diffraction des rayons X aux petits angles (SAXS) et par diffusion dynamique de lumière (DLS). Les activités catalytiques des nanoparticules ont été déterminées pour la réaction de réduction du p-nitrophénol (Nip) par NaBH4, dans l'eau ou dans des mélanges eau-éthanol. Parmi les différentes nanoparticules préparées, celles stabilisées par du dextran ou par le dérivé de maltoheptaose Mal7NAcC12 ont montré les meilleures propriétés catalytiques pour la réduction du Nip par NaBH4 avec des constantes de vitesse respectives de 1,41 et 1,11 s-1 m-2 L. Ces valeurs sont parmi les plus élevées de la littérature. L'effet du solvant et notamment de la présence d'éthanol sur les propriétés catalytiques des nanoparticules a également été évalué. Il a été montré que la présence d'éthanol inhibe l'activité des nanoparticules, probablement par formation d'une couche de solvant à la surface des particules entrant en compétition avec le réducteur. Enfin, trois systèmes différents (Ag-Mal7NAcC12 Ag-XGONAcC12 et Ag-LacNAcC12) ont été évalués comme biocapteurs potentiels pour la détection de lectines. Les nanoparticules Ag-Mal7NAcC12 en particulier ont permis la détection colorimétrique et sans marquage de la Concanavaline A. / The main goal of this work is the preparation, characterization and catalytic and lectins detection studies of silver nanoparticles (AgNPs) having sugar-based compounds as stabilizers. To achieve this goal two strategies were used, one using the polysaccharide dextran as stabilizer and other using amphiphile compounds based on oligosaccharides (maltose, lactose, maltoheptaose and xyloglucan). In both strategies the optimization of AgNPs preparation was realized using a multivariate analysis based in informations collected from the surface Plasmon resonance band (SPR) of AgNPs. All stable AgNPs were characterized by ultraviolet-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS) and dynamic light scattering (DLS) techniques. The catalytic activities of AgNPs were determined over the p-nitrophenol (Nip) reduction reaction by NaBH4, as reducing agent, in water or water-ethanol mixtures. Two different types of amphiphiles were synthesized, one with an alkyne group in the junction of a sugar block with a hydrophobic block and the other type with a carboxylic acid group in the end of hydrophobic part. The amphiphiles were characterized by 1H and 13C NMR and mass spectrometry. The Nip reduction reaction with NaBH4 showed the best catalytic activity with AgNPs-dextran and Ag-Mal7NAcC12 nanoparticles with the rate constant normalized to the surface area of the NPs per unit volume of 1.41 and 1.11 s-1 m-2 L, respectively. These values are among the highest ones found in literature. The solvent effect in this reaction was evaluated by mixtures of water and ethanol. Applying a pseudo-monomolecular surface reaction as an experimental artifice, the obtained kinetic data were treated according to the Langmuir model, which combined with water/ethanol surface tension observations revealed that addition of ethanol inhibit the reaction, most probably by competing with BH4- ions for the nanoparticles surface, with the formation of a solvent monolayer. Finally, three different systems (Ag-Mal7NAcC12, Ag-XGONAcC12 and Ag-LacNAcC12) were tested as sensor for lectin detection and Ag-Mal7NAcC12 nanoparticles showed specific interaction with the Concanavalin A.

published_or_final_version / Biochemistry / Master / Master of Philosophy

No description available.

Cell surface mannan oligosaccharides have been implicated in die pathogenesis of C. albicans through roles such as adhesion to host cells and modulation of the immune system (Calderone, 1993, Chaffin, 1998). Understanding the molecular biology of glycosylation is therefore critical to elucidating host-fungus interactions. The CaMNTI gene, responsible for adding the second mannose on 0-linked mannan has previously been shown to be important for adhesion and virulence in C. albicans (Buurman et ai, 1998). In this project, the CaMNT1 gene family was studied as a means to understand more about the roles of oligosaccharide synthesis in Candida-host interactions. The Camntlp enzyme was expressed heterologously in P. pastoris and its cofactor and acceptor specificities were determined. The key residues for the retaining mechanism of CaMntlp catalysis and for cofactor binding were determined by site-directed mutagenesis as Asp350, Glu-318, His-377 and His377. This knowledge may aid in the rational design of antifungals against the MNT1 family of Candida mannosyltransferases. Two further members of the gene fainily; CaMNT3 and CaMNT5 were disrupted using the ura-blaster technique. Deletion of CaMNT3 and to a lesser extent CaMNT5 led to strains unable to form hyphae on solid Spider medium. This phenotype is distinct from that reported for CaMNT1 and suggests a role for these genes upstream or downstream of the Cphlp MAP Itinase cascade that regulates yeast-hypha morphogenesis. The Camnt3 and CamntS nuU mutants were attenuated in virulence in a systemic mouse model of candidosis. The heterozygous mutants were more attenuated in virulence than the nuU mutants indicating that a compensation mechanism may upregulate expression of other MNT genes when both copies of CaMNTS or CaMNT3 are disrupted. This study has shown that glycan synthesis affects morphogenesis in C. albicans and indicates many cell wall proteins require to be glycosylated to perform their function.

No description available.

Isomalto-oligosaccharides (IMO) with α(1→6) and α(1→4) glucosidic linkages are produced by enzymatic conversion of starch. Isomalto-oligosaccharides are partially digested in the intestine but little information is available regarding their metabolim in vivo. It was the aim of this study to investigate IMO metabolism by lactobacilli and bifidobacteria and to determine the effect of IMO diet on intestinal microbiota in a rodent model, and a rodent model for inflammatory bowel disease (IBD). Different strains of bifidobacteria and lactobacilli were grown in de Man Rogosa Sharpe media with IMO as sources of carbohydrates. Substrates and metabolites of carbohydrates metabolism were analyzed. Lactobacilli metabolized isomaltose whereas isomalto-triose and higher degree of polymerisation (DP) oligosaccharides were metabolized by bifidobacteria first. To determine the modulating effects of IMO in the intestine, a group of six F344 rats were fed IMO diet for six weeks and compared to rats fed control diet. Assessment of intestinal microbiota and their metabolites was performed by PCR- denaturing gradient gel electrophoresis (PCR-DGGE), quantitative PCR (qPCR) and quantification of short chain fatty acids (SCFA). The Lactobacillus group was one of the dominant bacterial taxa in the fecal samples of rats. Isomalto-oligosaccharides selectively stimulated lactobacilli and increased their diversity in rats compared to those on control or inulin diet. The potential health benefit of IMO was evaluated in a rodent model for IBD. Three groups of HLA-B27 rats were fed IMO, fructo-oligosaccharides (FOS) or control diet for 12 weeks. The Lactobacillus group and bifidobacteria numbers were increased significantly in the fecal samples of rats fed IMO or FOS diet respectively. Numbers of Enterobacteriaceae family were significantly increased in the rats fed IMO or FOS diet compared to the control group. Clostridium coccoides group, Clostridium leptum group, Clostridium cluster XI and total number of bacteria were significantly decreased in the rats fed FOS diet compared to the rats fed control diet. Moreover, IMO and FOS diets showed a unique effect on intestinal microbiota compared to the control diet. Cecum histology scores showed a significant decrease of inflammation in the rats fed IMO or FOS diet compared to the rats fed control diet. / Food Science and Technology