Thesis (Ph.D.)--Murdoch University, 2006. / Thesis submitted to the Division of Science and Engineering. Includes bibliographical references (leaves 164-182).

Thèses (M.Sc.)--Université de Sherbrooke (Canada), 2001. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.

No description available.

No description available.

The GM2 gangliosidoses are a group of recessive disorders, which lead to the accumulation of GM2 ganglioside in neuronal cells. The genes responsible for these disorders are HEXA (Tay-Sachs disease and variants), HEXB (Sandhoff disease and variants) and GM2A (AB variant of GM2 gangliosidosis). We have established three relational locus-specific databases recording allelic variation at the HEXA, HEXB and GM2A genes, and these can be accessed through the G M2 Gangliosidoses home page (http://data.mch.mcgill.ca/gm2-gangliosidoses/). The purpose of these databases is to collect and distribute information on mutations in the genes responsible for GM2 gangliosidosis. These databases are available online for users to search and retrieve information about specific mutations either by mutation, phenotype or author(s). In addition, submission forms are available for the addition of new mutations to the databases. / In order to provide information concerning the effects of mutations on the manifestations of disease, we proceeded to model on the theoretical model of the alpha subunit a few missense mutations. (Abstract shortened by UMI.)

Thesis (MSc)--University of Stellenbosch, 2007. / Bibliography. Also available via the Inernet.

No description available.

A number of exoglycosidases have been prepared from bacterial and plant sources using established methods for the separation of enzymes, in conjunction with certain novel purification systems hitherto not described in the literature for these enzymes. The enzyme, beta-galactosidase from E. coli has been prepared using previously described methods of phase separation and ion-exchange chromatography. As a final step in this purification, the use of a new hydroxyl-rich chromatographic support for the isolation of high-grade enzyme suitable for use in enzyme immunoassays was investigated. Methods have also been studied for the recovery of alpha-mannosidase as a by-product of the procedure used for the extraction of urease from jack bean (Canavalia ensiformis). The inclusion of a novel step involving the use of hydrophobic-interaction chromatography on Phenyl-Sepharose led to excellent recoveries of enzyme suitable for commercial use. Studies on a second glycosidase, beta-N-acetylhexosaminidase, from the same source (jack bean) paved the way for an adaptation of existing purification methods to provide increased yields and an improved quality of enzyme. Since the research unit in which this work was performed is associated with commercial organizations responsible for the preparation and marketing of biologically active products, it is important that the methods of purification described in this thesis are compatible with the requirements for largescale purification.

No description available.

Grape-derived aroma and flavor precursors exist partially as non-volatile, sugar-bound glycosides. Hydrolysis of these compounds may modify sensory attributes and potentially enhance wine quality. Cold soak (prefermentation skin contact) at two temperatures and alcohol content (%, v/v) at dejuicing were monitored to determine effects on Cabernet Sauvignon glycoside concentration. Total, phenolic-free, and red-free glycoside concentrations were estimated by the quantification of glycosyl-glucose. Cold soak (5 days at 10° C) increased total glycosides by 77%, red-free glycosides by 80%, and phenolic-free glycosides by 96%. Ambient soak (3 days at 20° C) enhanced color extraction, and increased total glycosides by 177%, red-free glycosides by 144%, and phenolic-free glycosides by 106%. Wines produced by early pressing (10% sugar) had 25% more total and red-free glycosides than late press (0.25% sugar). After post-fermentation malolactic fermentation, total glycosides were 14% lower and phenolic-free glycosides were 35% lower. In a second study, the activities of a-L-arabinofuranosidase, b-glucosidase, and a-L-rhamnoyranosidase were determined in model systems for thirty-two strains of yeasts belonging to the following genera: Aureobasidium, Candida, Cryptococcus, Hanseniaspora, Hansenula, Kloeckera, Metschnikowia, Pichia, Saccharomyces, Torulaspora, and Brettanomyces (10 strains); and seven bacteria (Leuconostoc oenos strains). Only one Saccharomyces strain exhibited -glucosidase activity, but several non-Saccharomyces yeast species had substantial production. Aureobasidium pullulans hydrolyzed a-L-arabinofuranoside, b-glucoside, and a-L-rhamnoyranoside. Eight Brettanomyces strains had -glucosidase activity. Location of enzyme activity was determined for those species with enzymatic activity. The majority of -glucosidase was located in the whole cell fraction (66%), followed by the permeabilized fraction (35%), and extracellular production (2%). Aureobasidium pullulans was also capable of hydrolyzing grape glycosides. / Master of Science