Choi Pui-yu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 113-123). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (Chinese Version) --- p.iii / Acknowledgements --- p.v / List of Abbreviations --- p.vi / Table of Contents --- p.viii / List of Tables --- p.xii / List of Figures --- p.xiii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Literature Review / Chapter 2.1 --- Mushroom Polysaccharides with Antitumor Activities --- p.7 / Chapter 2.1.1 --- Antitumor β-Glucans --- p.7 / Chapter 2.1.2 --- Antitumor Heteroglycans --- p.9 / Chapter 2.1.3 --- Antitumor Polysaccharide-Protein Complexes --- p.12 / Chapter 2.2 --- Antitumor Activities and Structural Characteristics of Mushroom Polysaccharides --- p.15 / Chapter 2.3 --- Antitumor Effects of Mushroom Polysaccharides In Vitro --- p.19 / Chapter 2.4 --- Antitumor Effects of Mushroom Polysaccharides In Vivo --- p.21 / Chapter 2.5 --- Immunomodulatory Activities --- p.24 / Chapter 2.6 --- Activation of Cytokines by Mushroom Polysaccharides --- p.28 / Chapter 2.7 --- Induction of Nitric Oxide Synthase by Mushroom Polysaccharides --- p.32 / Chapter 2.8 --- Tremella aurantialba --- p.34 / Chapter Chapter 3 --- Materials and Methods --- p.35 / Chapter 3.1 --- Extraction --- p.35 / Chapter 3.1.1 --- Extraction of Crude Tremella aurantialba Polysaccharide --- p.35 / Chapter 3.1.2 --- Fractionation --- p.38 / Chapter 3.1.3 --- Polysaccharide and Protein Content Determination --- p.38 / Chapter 3.1.3.1 --- Phenol-Sulfuric Assay --- p.39 / Chapter 3.1.3.2 --- Lowry-Folin Method --- p.39 / Chapter 3.1.4 --- Gas Chromatography (GC) --- p.40 / Chapter 3.1.5 --- Modified Carbazole Assay --- p.41 / Chapter 3.1.6 --- High Performance Liquid Chromatography (HPLC) --- p.42 / Chapter 3.2 --- In Vitro Studies --- p.43 / Chapter 3.2.1 --- Maintenance of Cell Lines --- p.43 / Chapter 3.2.2 --- Effect on Cancer Cell Lines --- p.43 / Chapter 3.2.2.1 --- Trypan Blue Exclusion Methods --- p.44 / Chapter 3.2.2.2 --- MTT Assay --- p.44 / Chapter 3.2.3 --- Effect on Normal Cell Line --- p.45 / Chapter 3.2.4 --- Coulter Counter --- p.46 / Chapter 3.3 --- In Vivo Studies --- p.47 / Chapter 3.3.1 --- Animals --- p.47 / Chapter 3.3.2 --- Maintenance of Sarcoma 180 Cell Line --- p.47 / Chapter 3.3.3 --- Effect of TAP Fractions on Sarcoma 18 Solid Tumor --- p.48 / Chapter 3.3.3.1 --- Injection of TAP Fractions 24 h After Transplantation --- p.48 / Chapter 3.3.3.2 --- Injection of TAP Fractions 72 h After Transplantation --- p.49 / Chapter 3.4 --- Effect of TAP Fractions on Modulating mRNA Expression of Cytokines and Nitric Oxide Synthase --- p.51 / Chapter 3.4.1 --- Treatment of Mice --- p.51 / Chapter 3.4.2 --- Isolation of Splenocytes and Peritoneal Exduate Cells --- p.51 / Chapter 3.4.3 --- Extraction of Total mRNA from Splenocyte and Peritoneal Exduate Cells --- p.52 / Chapter 3.4.4 --- Reverse Transcription-Polymerase Chain Reaction (RT-PCR) --- p.53 / Chapter 3.4.4.1 --- Reverse Transcription --- p.53 / Chapter 3.4.4.2 --- Polymerase Chain Reaction --- p.56 / Chapter 3.4.5 --- DNA Sequencing --- p.57 / Chapter 3.5 --- Statistical Analysis --- p.58 / Chapter Chapter 4 --- Results --- p.59 / Chapter 4.1 --- Isolation and Characterization of TAP Fractions --- p.59 / Chapter 4.1.1 --- Percentage Yield of TAP Fractions --- p.59 / Chapter 4.1.2 --- Polysaccharide and Protein Content of TAP Fractions --- p.59 / Chapter 4.1.3 --- Relative Monosaccharide Contents in TAP Fractions --- p.60 / Chapter 4.1.4 --- Results of HPLC --- p.60 / Chapter 4.2 --- Effects of TAP Fractions In Vitro --- p.69 / Chapter 4.2.1 --- Effects of TAP Fractions on Suspension Cancer Cell Lines --- p.69 / Chapter 4.2.2 --- Effects of TAP Fractions on Adhesion Cancer Cell Lines --- p.69 / Chapter 4.2.3 --- Effects of TAP Fractions on Normal Cell Line --- p.70 / Chapter 4.2.4 --- Effect of TAP 2 on HL-60 Cell Line as Evaluated by Coulter Counter --- p.70 / Chapter 4.3 --- Antitumor Effect of TAP Fractions In Vivo --- p.78 / Chapter 4.4 --- Effect of TAP Fractions on Modulating mRNA Expressions of Cytokines and Nitric Oxide Sythase (NOS) --- p.83 / Chapter 4.4.1 --- Results of RT-PCR --- p.83 / Chapter 4.4.2 --- Sequencing --- p.84 / Chapter Chapter 5 --- Discussion --- p.91 / Chapter 5.1 --- Characterization of TAP Fractions --- p.91 / Chapter 5.2 --- Antitumor Effects of TAP Fractions In Vitro --- p.96 / Chapter 5.3 --- Furhter Study --- p.109 / Chapter Chapter 6 --- Conclusion --- p.111 / References --- p.113

Poon Shuk-ching. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 113-125). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / Abstract (Chinese Version) --- p.iv / Table of Contents --- p.vi / List of Tables --- p.x / List of Figures --- p.xi / List of Abbreviations --- p.xiii / Chapter Chapterl 1 --- ntroduction --- p.1 / Chapter Chapter 2 --- Literature Review --- p.5 / Chapter 2.1 --- Mushroom Polysaccharides From Basidiomycetes --- p.5 / Chapter 2.1.1 --- Antitumor and Immunomodulatory Activity --- p.6 / Chapter 2.1.2 --- Antiviral Activity --- p.9 / Chapter 2.1.3 --- Hypoglycermic Activity --- p.11 / Chapter 2.1.4 --- Free Radical Scavenging Activity --- p.11 / Chapter 2.2 --- Mushroom Dictyophora indusiata --- p.13 / Chapter 2.2.1 --- Nutritional Value --- p.13 / Chapter 2.2.2 --- Structural Characteristic of Dictyophora indusiata Polysaccharides --- p.14 / Chapter 2.2.3 --- Biological Activity --- p.16 / Chapter 2.3 --- In vivo Antitumor Study --- p.19 / Chapter 2.4 --- Induction of Cytokines Production in Immune System --- p.21 / Chapter 2.5 --- In vitro Antitumor Study --- p.25 / Chapter 2.6 --- Cell Cycle Regulation --- p.28 / Chapter Chapter 3 --- Materials & Methods --- p.34 / Chapter 3.1 --- Extraction --- p.34 / Chapter 3.1.1 --- Extraction of Dictyophora indusiata Polysaccharides --- p.34 / Chapter 3.1.2 --- Purification of Dictyophora indusiata Polysaccharides --- p.35 / Chapter 3.1.2.1 --- Preparation of DEAE-cellulose Ion Exchanger --- p.35 / Chapter 3.1.2.2 --- Fractionation --- p.35 / Chapter 3.2. --- Characterization of Dictyophora indusiata Polysaccharides --- p.39 / Chapter 3.2.1 --- Polysaccharide Content Determination --- p.39 / Chapter 3.2.2 --- Protein Content Determination --- p.39 / Chapter 3.2.3 --- Gas Chromatography (GC) --- p.40 / Chapter 3.2.4 --- Uronic Acid Content Determination --- p.42 / Chapter 3.2.5 --- High Performance Liquid Chromatography (HPLC) --- p.43 / Chapter 3.3 --- In vivo Studies --- p.44 / Chapter 3.3.1 --- Animals --- p.44 / Chapter 3.3.2 --- Maintenance of Sarcoma 180 Cell Line --- p.44 / Chapter 3.3.3 --- Effect of DI3 Fraction on Sarcoma 180 Solid Tumor --- p.45 / Chapter 3.3.4 --- Effect of DI3c Fraction on Tumor Necrosis Factor-Alpha (TNF-α) and Interleukin 2 (IL-2) Production --- p.47 / Chapter 3.3.4.1 --- Treatment of Mice --- p.47 / Chapter 3.3.4.2 --- Preparation of Mouse Serum --- p.47 / Chapter 3.3.4.3 --- Enzyme-linked Immunosorbent Assay (ELISA) for TNF-α Production --- p.48 / Chapter 3.3.4.4 --- Enzyme-linked Immunosorbent Assay (ELISA) for IL-2 Production --- p.49 / Chapter 3.4 --- In vitro Studies --- p.51 / Chapter 3.4.1 --- Maintenance of Cell Lines --- p.51 / Chapter 3.4.2 --- Effect on Cancer Cell Lines --- p.52 / Chapter 3.4.3 --- Cytotoxicity on Normal Cell Line --- p.52 / Chapter 3.4.4 --- Trypan Blue Exclusion Method --- p.53 / Chapter 3.4.5 --- MTT Assay --- p.54 / Chapter 3.4.6 --- BrdU Incorporation --- p.55 / Chapter 3.5 --- Statistical Analysis --- p.56 / Chapter Chapter 4 --- Results --- p.57 / Chapter 4.1 --- Extraction and Fractionation of Polysaccharides from Dictyophora indusiata --- p.57 / Chapter 4.1.1 --- Percentage Yield of Crude DI Polysaccharides --- p.57 / Chapter 4.1.2 --- Percentage Yield of DI3 Fractions --- p.57 / Chapter 4.2 --- Characterization of DI3 Fractions --- p.62 / Chapter 4.2.1 --- Polysaccharide and Protein Contents of DI3 Fractions --- p.62 / Chapter 4.2.2 --- Relative Monosaccharide and Uronic Acid Content in Different DI3 Fractions --- p.62 / Chapter 4.2.3 --- Estimated Molecular Weight of DI3 Fractions --- p.65 / Chapter 4.3 --- Antitumor Effect of Dictyophora indusiata Polysaccharides In vivo --- p.70 / Chapter 4.3.1 --- In vivo Antitumor Effect of Crude DI Polysaccharides --- p.70 / Chapter 4.3.2 --- In vivo Antitumor Effect of Various Fractions of DI3 --- p.70 / Chapter 4.3.3 --- Effect of DI3c on TNP-α and IL-2 Production in Mice --- p.78 / Chapter 4.4 --- In vitro Effects of DI3 Fractions on Cell Density and Viability on Normal and Cancer Cell Lines --- p.86 / Chapter 4.4.1 --- Effects of DI3 Fractions on Cell Density and Viability of Human Leukemic HL-60 and K-562 and Mouse Sarcoma 180 Cells --- p.86 / Chapter 4.4.2 --- Effects of DI3 Fractions on the Growth of Human Liver Cancer HepG2 and Normal Monkey Kidney Vero Cells --- p.86 / Chapter 4.4.3 --- Effect of DI3b Fraction on Proliferation of HL-60 Cells Determined by BrdU Incorporation --- p.94 / Chapter Chapter 5 --- Discussions --- p.96 / Chapter 5.1 --- Extraction and Characterization of DI3 Fractions --- p.96 / Chapter 5.2 --- Antitumor Effects of Dictyophora indusiata Polysaccharides --- p.101 / Chapter 5.3 --- Further Studies --- p.109 / Chapter Chapter 6 --- Conclusion --- p.111 / References --- p.113

La paroi végétale est une structure complexe composée principalement de polysaccharides (cellulose, hémicellulose et pectine), de lignine et de protéines. Elle est impliquée dans de nombreuses fonctions essentielles à la vie de la cellule végétale. De plus, les constituants de cette paroi, que sont les polysaccharides et la lignine, représentent la plus grande source de carbone renouvelable de la planète. Ceci en fait des cibles de choix notamment pour la production d'énergies « vertes ». Toutefois, l'utilisation des polysaccharides tels que les hémicelluloses constituant la paroi végétale reste, à l'heure actuelle, limitée du fait de la difficulté à les dégrader. Ces dernières années, un effort important a été mis en œuvre pour identifier et caractériser de nouvelles enzymes, telles que les glycosides hydrolases, permettant de dégrader efficacement la biomasse végétale. Dans le but de découvrir de nouvelles enzymes impliquées dans la dégradation de la biomasse végétale, des chercheurs de l'équipe « Catalyse et Ingénierie Moléculaire Enzymatiques » du LISBP ont décidé d'explorer le métagénome d'organismes connus pour dégrader la biomasse végétale. Deux espèces animales ont fait l'objet d'analyses : tout d'abord les termites qui sont considérés comme les champions de la dégradation de la biomasse végétales et souvent comparés à des bioréacteurs, et le ver de terre. Des banques métagénomiques de trois espèces différentes de termites ainsi qu'une banque métagénomique de ver de terre ont ainsi été créées. Dans ces travaux de thèse deux des banques métagénomiques de termites, celle de Nasutitermes corniger et celle de Termes hispaniolae, ont fait l'objet d'une étude afin de comparer le potentiel hémicellulolytique de ces deux espèces. Après sélection de nombreux clones positifs sur substrats chromogéniques de chacune des deux banques, séquençage puis annotation taxonomique et fonctionnelle, un grand nombre d'enzymes et principalement des glycosides hydrolases, a pu être identifié. Les résultats montrent que le métagénome de Nasutitermes corniger présente majoritairement des enzymes à activité endoglycosidase alors que le métagenome de Termes hispaniolae possède plutôt des enzymes à activité exoglycosidase. Toutes les activités trouvées dans chacune des espèces de termite sont en bonne corrélation avec l'alimentation du termite. De plus, nous avons observé que le microbiote intestinal des deux termites ne possèdent pas les mêmes embranchements bactériens majoritaires et nous avons pu voir que le microbiote de Termes hispaniolae est plus diversifié ce qui corrèle aussi avec l'alimentation des deux termites. D'autre part, dans la banque métagénomique du ver de terre, l'annotation fonctionnelle a révélé une enzyme intéressante. Il s'agit d'une enzyme annotée par B. Henrissat (responsable de la base de données CAZy) comme étant une glycoside hydrolase putative mais n'appartenant à aucune des 135 familles de glycosides hydrolases existantes. Cette enzyme putative, appelée GH* présente des similitudes avec les GH de la famille 5 sans pour autant appartenir à cette famille du fait notamment de l'absence du résidu catalytique nucléophile conservé. Une étude structurale et fonctionnelle de GH* a donc été menée. Les expériences ont permis de prouver que GH* est une endo-xylanase ayant une préférence pour les arabinoxylanes et les xylooligosaccharides de degré de polymérisation d'au moins 5 ou 6. La structure tridimensionnelle de GH* à 1,6Å de résolution a été obtenue par cristallographie des rayons X par remplacement moléculaire à l'aide d'une GH5. Cette structure a permis de confirmer l'identité du résidu acide/base identifié par alignement de séquences et d'émettre une hypothèse sur l'identité du résidu nucléophile. Enfin des mutants de GH* pour ces deux résidus ont été obtenus et ont confirmé leur implication dans l'activité de l'enzyme. / Plant cell wall is a complex structure surrounding plant cells mainly composed by polysaccharides (cellulose, hemicellulose and pectin), lignin and proteins. The plant wall maintains and imposes the size and shape of cells. It is also important for exchanges between cells and extra cellular medium. The polysaccharides of this cell wall are the largest renewable carbon source on the earth, which makes them good targets to produce green energies. Because plant cell wall is difficult to degrade, its use for biofuels for is still limited. However, some organisms are able to efficiently degrade this biomass. Exploring the diversity of the living word to discover new effective biocatalysts has grown considerably last years, because of the emergence of metagenomics. In this context and to discover new enzymes involved in the degradation of plant biomass, the team « Catalyse et Ingénierie Moléculaire Enzymatiques » of LISBP decided to explore metagenome of organisms known to degrade plant biomass. Two animal families were chosen for metagenomics analysis, the termite and earthworm. Metagenomics banks of three different species of termite and one metagenomics bank of an earthworm were created. In this thesis project, two of the three metagenomics banks of termites, the one from Nasutitermes corniger and the other one from Termes hispaniolae, were studied to compare the hemicellulolytic potential of these two species. After selection of many positive clones on chromogenic substrates of both banks, sequencing, taxonomic and functional annotations, a large number of enzymes and mainly glycoside hydrolases, could be identified. The results obtained shown that the trends observed during functional screens were maintained. Indeed, it appears that Nasutitermes corniger has a majority of endoglycosidases while Termes hispaniolae has mainly exoglycosidases. Thereby, families of enzymes highlighted allowed correlating their hydrolytic activities with the diet of these species. Furthermore, we observed that the intestinal microbiota of each termite is different. Indeed, both termites do not have the same majority bacterial phyla and the microbiota of Termes hispaniolae is more diverse than the one of Nasutitermes corniger. On the other hand, functional annotation of the metagenomics bank of the earthworm revealed an enzyme annotated as a glycoside hydrolase no belonging to any of the 135 glycoside hydrolase existing families. This enzyme, named GH*, seems to be close to GH5 but does not shown the nucleophilic catalyst residue perfectly conserved in this glycoside hydrolase family. A functional and structural study of GH* was then done. We have shown that GH* is an endo-xylanase which prefers arabinoxylans and xylooligosaccharides having a polymerization degree greater than 5. In addition, we determined the crystal structure of GH* at 1.6Å resolution. This 3D structure has confirmed the presence of the acid/base residue identified by sequence alignment and allowed us to hypothesize about the identity of the nucleophilic residue. Finally, mutants of GH* for these two residues were obtained and confirmed their involvement in the activity of the enzyme. We were able to progress in the understanding of structure/function relationships of this protein.

Call number: LD2668 .T4 1985 M86 / Master of Science

published_or_final_version / abstract / Paediatrics and Adolescent Medicine / Doctoral / Doctor of Philosophy

The effect of frozen storage time on the composition of the cell wall polysaccharide (CWP) of muskmelon (Cucumis melo) cultivars at different stages of maturity was investigated. Changes in composition, firmness, drip loss, and color of Cantaloupe and Honey Dew melon flesh were determined at three stages of maturity and for three periods of storage at -23°C. Relationships between firmness, drip loss, and other composition measurements, as well as the total CWP sugar composition, were also determined. Cell wall polyssacharides were isolated and purified, and fractionations were performed using cyclohexane trans- 1,2-diamine tetraacetate (CDTA), Na₂C0₃, guanidinium thiocyanate (GTC), and KOH. All fractions and residues were dialysed and then freeze-dried. Following hydrolysis of CWP fractions with trifluoroacetate (TFA), the alditol acetate derivatives of neutral sugars from each CWP fraction were prepared and analyzed by gas chromatography, using myo-inositol as the internal standard. TFA insoluble fractions were analyzed colorimetrically using phenol-sulphuric acid reagent. Uronic acid was determined using 0.15% m-hydroxybiphenyl for absorbance at 520 nm with galacturonic acid as the standard. It was determined that CDTA and Na₂C0₃ fractions were composed of typical pectic materials, containing mostly galacturonic acid with the neutral sugars arabinose, galactose, rhamnose, and a smaller amount of xylose. As maturity increased, CDTA fraction yields increased, though total neutral sugar CWP compositions decreased. GTC and KOH fractions were typical of hemicellulose, and contained principally xylose, glucose, galactose, mannose, and fucose, with very small amounts of uronic acid, arabinose, and rhamnose. Residue fractions contained principally glucose and galactose, with smaller amounts of mannose, xylose, arabinose, and fucose. With the exception of xylose and glucose, all neutral sugars decreased significantly (p < 0.01) as maturity increased in both the Cantaloupe and Honey Dew melons. Total uronic acid did not change as maturity increased, except for Cantaloupe, where total uronic acid decreased from the ripe to overripe stages. The CDTA fraction yield increased and all neutral sugars decreased significantly (p < 0.05) as storage time was increased. Only the CDTA fraction yield was negatively correlated with the firmness of both melons, and was positively correlated with drip loss as maturity and frozen storage time were increased. Firmness was positively correlated with Na₂C0₃ and GTC fraction yield in Cantaloupe, whereas for Honey Dew there was no correlation between firmness and Na₂C0₃ or GTC fraction yield as maturity increased. The KOH fraction was negatively correlated with firmness in Cantaloupe, whereas there was no correlation between firmness and KOH fractions in Honey Dew existed as maturity increased. The residue fractions increased in both melons only from the underripe to the ripe stages, and did not change from ripe to overripe. Firmness was positively correlated with total rhamnose, arabinose, mannose, and galactose as maturity increased, and the drip loss was negatively correlated with all total neutral sugars as storage time was increased. During frozen storage, there was a significant decreases (p < 0.05) in total CWP sugars in relation to increased storage time. The decrease in total sugars was more dramatic during the 0 to 5 month period than the 5 to 10 month period of frozen storage. Galactose did not change in the Cantaloupe, whereas in Honey Dew it decreased 34.3% from 0 to 5 months then decreased only 13% from 5 to 10 months of storage. / Graduation date: 1994

No description available.

No description available.

No description available.

Les alginates sont des polysaccharides naturels extraits des algues brunes, capables de réticuler instantanément en formant un gel au contact des ions calcium. L'objet de cette thèse est d'utiliser ces alginates au sein de formulations détergentes capables de dégraisser les surfaces de matériaux composites usinés. Les solutions détergentes sont spécifiquement formulées pour être compatibles avec les alginates afin d'empêcher leur dégradation tout en permettant leur réticulation après action détergente. La faisabilité du procédé a été démontrée et ses paramètres critiques ont été identifiés et étudiés.Le principal avantage de ce procédé est qu'il permet, contrairement aux solutions de dégraissage lessivielles traditionnelles, de ne pas gaspiller d'eau tout en offrant un moyen rapide et efficace de dégraisser les surfaces. / Abstract