Two studies were conducted to evaluate the effects of diet on phosphorus (P) digestion in dairy cattle. The objective of the first study was to evaluate the effects of forage and non-fiber carbohydrate (NFC) content on total P (TP) and inositol phosphates-P (IPs-P) digestion. Samples of feed, duodenal digesta and feces from a previously conducted study were analyzed for TP and IPs-P. In this study, eight lactating Holstein cows were fed diets containing either 60 or 35% forage and either 30 or 40% NFC in a 2 × 2 factorial with replicated 4 × 4 Latin square design. Dietary TP content (% DM) was 0.35, 0.36, 0.36, 0.36 and dietary IPs-P content (%DM) was 0.08, 0.13, 0.06, 0.11 for diets with forage: NFC ratio 35:30, 35:40, 60:30, and 60:40, respectively. Increasing dietary forage content decreased IPs-P and TP intake, fecal TP excretion, and total tract IPs-P digestibility (72.4 vs. 61.4%). Fecal IPs-P excretion tended to decrease as increasing forage content. Duodenal IPs-P and TP flow and apparent TP digestibility were unaffected by forage content. Increasing dietary NFC content increased IPs-P and TP intake, duodenal IPs-P flow, fecal IPs-P excretion, total tract IPs-P digestibility (61.4 vs. 72.4%), and apparent TP digestibility (32.8 vs. 41.6%). Dietary forage and NFC content affected IPs-P and TP digestion. The second study was to evaluate the effects of increasing dietary beet pulp (BP) content to replace high moisture corn (HMC) on ruminal and post-ruminal digestion of TP and IPs-P. Eight lactating Holstein cows were fed diets containing 0, 6.1, 12.1 or 24.3% BP in a replicated 4 × 4 Latin square design. Samples of rumen contents, duodenal digesta, and feces from this previously conducted study were analyzed for TP and IPs-P content. Linear and quadratic effects of BP content were analyzed using Proc Mixed of SAS. Dietary TP and IPs-P content were reduced linearly with increasing BP (0.59, 0.58, 0.57, 0.56% TP and 0.15, 0.14, 0.13, 0.11% IPs-P). Intake, ruminal content, and rumen pool size of TP decreased with increasing BP content. Digestion of TP and duodenal flow and fecal excretion of IPs-P and TP were not affected. With increasing dietary BP content, IPs-P intake was reduced, ruminal IPs-P pool size was reduced, and rumen turnover time (h) of IPs-P was increased. Apparent ruminal IPs-P digestibility (36.5, 31.8, 24.6, 13.6 %) and apparent total tract IPs-P digestibility (85.3, 82.7, 82.1, 79.1%) decreased linearly with increasing BP. Fecal excretion of IPs-P averaged 5.2 g/d. Replacing HMC with BP reduced digestion of IPs-P. The majority of IPs-P disappearance occurred post-ruminally. In conclusion, dietary BP, forage, and NFC content affected IPs-P digestion in dairy cows. / Master of Science

BACKGROUND: The half-time (HT) period of a soccer match is viewed as a period for recovery. Completely inactive and passive HT has implications on metabolic responses and subsequent performance during the initial phases of the second half. PURPOSE: Determine the effects of an active rewarm-up, compared to a passive period, at halftime on various measures of performance during the first 15-minutes of the second half using global positioning system (GPS) units. Identify the effects of the active versus passive HT period, with CHO beverage supplementation, on blood parameters. METHODS: Crossover design study, twenty collegiate male soccer players participated in two 90-minute soccer matches with passive rest (CON) or a moderate-intensity rewarm-up (RWU) during HT with CHO supplementation. Subjects received five fingerstick blood samples throughout the match (BG) and four subjects had serum insulin/BG taken three times during the match. RESULTS: RWU had significantly (p<0.05) higher measures for total distance, average speed, speed exertion, accelerations, HMP distance, decelerations, and EE during TI-4 half when compared to CON. No subjects experienced hypoglycemia. However, CON did have a significant drop in BG after HT and the lowest mean BG taken at 60-minutes. Tendency for CON and RWU to have HT insulin levels that were elevated and reduced, respectively. CONCLUSION: A passive HT period is not optimal, given its causal role in temporary physical performance deficits in the second half of soccer matches. The results provide a strong rationale for collegiate soccer players and teams to incorporate the 8-minute RWU into the HT regime to optimize second half performance. / Master of Science

La synthèse de nano-object connait un essor grandissant depuis ces 20 dernières années. Les études fondamentales de système a permis (et permet encore) de trouver de nombreux domaines d'application aux nanotechnologies, que ces soit en catalyse, en électronique, dans le domaine biomédical...La thèse se déroule autour de deux axes de recherches: la synthèse et la description des propriétés magnétique de nanoparticules de fer stabilisé par des liquides ioniques, et la synthèse, l'étude magnétique, et leur évaluation en tant qu'agent de contraste et médiateur d'hyperthermie de nanoparticules de de ferrite fonctionnalisé par des dérivées carbohydrates. / The synthesis of nano-object is growing in the last 20 years. Basic research system has (and still allows) to find many areas of application for nanotechnology that is in catalysis, electronics, biomedical ...The thesis proceeds along two lines of research: the synthesis and the description of magnetic properties of iron nanoparticles stabilized by ionic liquids, and the synthesis, magnetic study, and their evaluation as a contrast agent and hyperthermia mediator of functionalized carbohydrate derivatives ferrite nanoparticles.

Non-catalytic protein-carbohydrate interactions are an essential element of various biological events. This dissertation presents the work on understanding carbohydrate recognition mechanisms and their physical significance in two groups of non-catalytic proteins, also called lectins, which play key roles in major applications such as cellulosic biofuel production and drug delivery pathways. A computational approach using molecular modeling, molecular dynamic simulations and free energy calculations was used to study molecular-level protein-carbohydrate and protein-protein interactions. Various microorganisms like bacteria and fungi secret multi-modular enzymes to deconstruct cellulosic biomass into fermentable sugars. The carbohydrate binding modules (CBM) are non-catalytic domains of such enzymes that assist the catalytic domains to recognize the target substrate and keep it in proximity. Understanding the protein-carbohydrate recognition mechanisms by which CBMs selectively bind substrate is critical to development of enhanced biomass conversion technology. We focus on CBMs that target both oligomeric and non-crystalline cellulose while exhibiting various similarities and differences in binding specificity and structural properties; such CBMs are classified as Type B CBMs. We show that all six cellulose-specific Type B CBMs studied in this dissertation can recognize the cello-oligomeric ligands in bi-directional fashion, meaning there was no preference towards reducing or non-reducing end of ligand for the cleft/groove like binding sites. Out of the two sandwich and twisted forms of binding site architectures, twisted platform turned out to facilitate tighter binding also exhibiting longer binding sites. The exterior loops of such binding sites were specifically identified by modeling the CBMs with non-crystalline cellulose showing that high- and low-affinity binding site may arise based on orientation of CBM while interacting with non-crystalline substrate. These findings provide various insights that can be used for further understanding of tandem CBMs and for various CBM based biotechnological applications. The later part of this dissertation reports the identification of a physiological ligand for a mammalian glycoprotein YKL-40 that has been only known as a biomarker in various inflammatory diseases and cancers. It has been shown to bind to oligomers of chitin, but there is no known function of YKL-40, as chitin production in the human body has never been reported. Possible alternative ligands include proteoglycans, polysaccharides, and fibers such as collagen, all of which make up the mesh comprising the extracellular matrix. It is likely that YKL-40 is interacting with these alternative polysaccharides or proteins within the body, extending its function to cell biological roles such as mediating cellular receptors and cell adhesion and migration. We considered the feasibility of polysaccharides, including cello-oligosaccharides, hyaluronan, heparan sulfate, heparin, and chondroitin sulfate, and collagen-like peptides as physiological ligands for YKL-40. Our simulation results suggest that chitohexaose and hyaluronan preferentially bind to YKL-40 over collagen, and hyaluronan is likely the preferred physiological ligand, as the negatively charged hyaluronan shows enhanced affinity for YKL-40 over neutral chitohexaose. Collagen binds in two locations at the YKL-40 surface, potentially related to a role in fibrillar formation. Finally, heparin non- specifically binds at the YKL-40 surface, as predicted from structural studies. Overall, YKL-40 likely binds many natural ligands in vivo, but its concurrence with physical maladies may be related to the associated increases in hyaluronan.

In this thesis the synthesis of several hydrolytically stable carbohydrate mimics with the potential to function as glycosidase or lectin inhibitors are described. This work is presented in Chapters 2-5. Chapters 2 and 3 describe synthetic efforts for producing carbasugars, and include the first synthesis of 1,2-bis-epi-valienamine and the preparation of two previously known aminocarbasugars. All three compounds were synthesised starting from D-mannose, using ring-closing metathesis as the key step. 1,2-Bis-epi-valienamine was found to inhibit Cellulomonas fimi β-mannosidase with a Ki value of 140 mM. Also included is the development of a novel synthetic route from cheap D-fructose to three mannose-mimicking carbasugars using a ring-closing metathesis strategy. Two of the compounds are potential inhibitors of the FimH adhesin. In Chapters 4 and 5 the synthesis of a number of pseudodisaccharides are presented; valienamine- and epi-valienamine-containing pseudodisaccharides and a small library of S-linked pseudodisaccharides were prepared. Various synthetic strategies were explored, including an alkylation strategy, Mitsunobu couplings, and sulfonate displacements. This is the first report on the synthesis of a valienamine pseudodisaccharide with β-lyxo-configuration. Two of the S-linked pseudodisaccharides were found to bind to Concanavalin A with high affinity. The final chapter (Chapter 6) of this thesis focuses on the development of a carbohydrate epimerisation method using transition metal catalysis. Two equilibrium constants involving gluco/manno- and gluco/allo-alcohols were determined via this method. / At the time od doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Manuscript. Paper 5: Manuscript.

Les interactions sucre-lectine jouent un rôle très important dans de nombreux processus biologiques comme les infections par des virus ou des bactéries. Toutefois, ces interactions étant faibles, la présentation de manière multivalente des résidus saccharidiques est nécessaire pour obtenir une augmentation significative des constantes d'association. Une technique basée sur l'utilisation de glycooligonucléotides et d'une puce à ADN utilisée comme plateforme d'ancrage a permis d'étudier l'affinité d'un grand nombre de composés envers les lectines PA-IL et PA-IIL de Pseudomonas aeruginosa et la lectine BambL de Burkholderia ambifaria. Les glycooligonucléotides ont été synthétisés, à partir de blocs de construction synthétisés en aval, en utilisant la chimie des acides nucléiques supportée et automatisée (phosphoramidites et H-phosphonate) ainsi que des réactions de « click chemistry » (la cycloaddition 1,3-dipolaire catalysée par le cuivre (I) ou le couplage thiol par addition de type Michael ou par substitution nucléophile d'un dérivé bromoacetamide).Les glycoclusters ayant montrés une bonne affinité envers les lectines cibles ont été sélectionnés et resynthétisés en solution sans l'étiquette ADN à l'échelle de la centaine de milligrammes. Les glycoclusters ainsi synthétisés en deux ou trois étapes avec une seule purification ont pu être évalués par quatre techniques d'analyse des interactions (HIA, ELLA, SPR et ITC) en présence des lectines PA-IL, PA-IIL et BambL. Nous avons trouvé un tétragalactocluster et un tétrafucocluster possédant une forte affinité envers la lectine PA-IL et BambL respectivement avec des valeurs de Kd de 157 nM et 43 nM. / Carbohydrate-lectin interactions play a key role in various biological processes such as infection by viruses or bacteria. As these interactions are weak, the multivalent association of carbohydrate is necessary to increase the binding constant. We used glycooligonucleotide and DNA chip to study the affinity of diverse compounds to PA-IL and PA-IIL lectins of Pseudomonas aeruginosa and Bambl lectin of Burkholderia ambifaria. Glycooligonucleotides were synthesized with previously prepared building blocks, using automated supported nucleic acid chemistry (phosphoramidites and H-phosphonate) and “Click chemistry” (copper (I) catalyzed 1,3-dipolar cycloaddition, thiol coupling by Michael addition and nucleophilic substitution of bromoacetamide derivative).Glycoclusters showing the better affinities toward the lectins have been synthesized to a hundred milligrams scale in solution without the DNA tag. The synthesis processes in two or three steps and only one final purification. Their interactions with the lectins PA-IL, PA-IIL and BambL were studied by several assays (HIA, ELLA, SPR and ITC). A tetragalactocluster and a tetrafucocluster showed high affinity toward respectively the lectin PA-IL (Kd = 157 nM) and the lectin BambL (Kd = 43 nM).

Les neurotoxiques organophosphorés (NOPs) sont des inhibiteurs irréversibles de l’acétylcholinestérase, une enzyme jouant un rôle clé dans la transmission de l’influx nerveux. Une intoxication par ces substances provoque de graves symptômes pouvant aboutir au décès des sujets empoisonnés. Bien qu’interdits par une convention internationale ratifiée par 190 pays, le contexte géopolitique actuel ravive la hantise d’une menace chimique contre des populations civiles, renouvelant l’intérêt de développer de nouveaux remèdes contre une intoxication aux NOP. A l’heure actuelle, les antidotes utilisés contre ces intoxications sont les mono- et bis- pyridinium aldoximes portant une ou deux charge(s) positive(s) permanente(s), qui présentent de nombreuses limitations, dont leur très faible capacité à traverser la barrière hémato-encéphalique et à réactiver efficacement les AChEs inhibées par les NOP dans le système nerveux central (SNC). Par ailleurs, leur efficacité est très dépendante de la nature du NOP utilisé, et il n’existe pas, aujourd’hui, de réactivateur universel. Dans ce contexte, le développement de nouveaux réactivateurs efficaces est un réel défi. Au cours de cette thèse, l’optimisation de la synthèse de cinq réactivateurs non chargés incorporant une amine cyclique en tant que ligand du site périphérique et la 3-hydroxypyridine aldoxime en tant que fonction réactivatrice a été développée pour évaluation in vivo. Dans cette continuité, vingt-et-un réactivateurs non chargés inédits comportant un ligand aminé du site périphérique de l’enzyme associée à la même fonction réactivatrice 3-hydroxypyridine aldoxime ont été conçus, synthétisés et testés sur l’AChE humaine inhibée par différents NOPs mais aussi sur les récepteurs nicotiniques. Certains d’entre eux ont été testés in vivo sur la souris. Parmi les réactivateurs synthétisés, certains possèdent des efficacités de réactivation identiques, voire meilleures que les oximes de référence utilisées de nos jours tout en ayant un effet antagoniste des récepteurs nicotiniques ouvrant ainsi la voie aux réactivateurs dits « Multi-cibles ». Avec comme objectif de traverser la barrière hémato-encéphalique en utilisant les transporteurs GLUTs présents sur les cellules endothéliales constituant cette barrière, quatre réactivateurs incorporant un motif carbohydrate ont été resynthétisés et évalués in vivo et in vitro. Enfin, de nouvelles fonctions réactivatrices constituées d’un motif thiadiazole-aldoxime et naphtaldoxime ont été étudiées ouvrant la voie à de nouvelles familles de réactivateurs et, pour la dernière fonction, remettant en cause le cahier des charges utilisé jusqu’alors pour la conception de nouveaux réactivateurs. / Organophosphorus nerve agents (OPNA) are irreversibly acetylcholinesterase (AChE) inhibitors, a key enzyme in the central nervos system playing a pivotal role in neurotransmission. OPNA poisoning induces to serious symptoms that can lead to death by respiratory failure. Despite an international convention prohibiting the use of chemical weapons, the current geopolitical context is reviving the fear of a chemical threat against civilian populations, and has renewed the interest of developing new remedies for OPNA poisoning. Nowadays, medical countermeasure used against OPNA intoxications are based on mono- and bis-pyridinium aldoximes carrying one or two permanent positive charge(s), which present many limitations, including their very low capacity to cross the blood-brain barrier and to reactivate effectively ChEs nhibited by NOPs in the central nervous system (CNS). Moreover, their effectiveness is highly dependent on the nature of the NOP used, therefore, there is no universal reactivator. In this context, the development of new effective reactivators is a real challenge. In this PhD, an optimized synthetic access to five uncharged reactivators incorporating a cyclic amine as peripheral site ligand and 3-hydroxypyridine aldoxime as reactivating function was developed for in vivo evaluation. Following up on this, twenty-one new uncharged reactivators bearing unprecedented cyclic amines as peripheral site ligand associated with our reactivating function were designed, synthetized and evaluated for reactivation on human AChE inhibited by several NOPs but also in vivo on mice and as antagonists on nicotinic receptors in vitro. Among these reactivators, some have identical or better reactivation efficiencies than the reference oximes used today while having a nicotinic receptor antagonist effect ; thus, paving the way for « Multi-target » reactivators. Aiming at an active BBB crossing using the GLUTs receptors, four reactivators including a carbohydrate moiety have been resynthetized and biologically evaluated. Last but not least, new reactivator functions consisting of a thiadazole-aldoxime and naphtaldoxime moieties have been studied, paving the way to new families of uncharged reactivators and, especially for the last function, calling into question design specifications of new reactivators.

No description available.

No description available.

This thesis mainly deals with the development of photochemical approaches to immobilize carbohydrates on surfaces for glycobiological studies. These approaches have been incorporated into a number of state-of-the-art nanobio-platforms, including carbohydrate microarrays, surface plasmon resonance (SPR), quartz crystal microbalance (QCM), atomic force microscopy (AFM), and glyconanomaterials. All the surfaces have displayed good binding capabilities and selectivities after functionalization with carbohydrates, and a range of important data have been obtained concerning surface characteristics and carbohydrate-protein interactions, based on the platforms established. Besides, a variety of non-carbohydrate and carbohydrate-based molecules have been synthesized, during which process the mutarotation of 1-glycosyl thiols and the stereocontrol in 1-S-glycosylation reactions have been thoroughly studied. / QC 20111004