• Login
    View Item 
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Studies on chromium-containing fractions in yeast and their relation to the proposed glucose tolerance factor : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Chemistry at Massey University, New Zealand

    Icon
    View/Open Full Text
    02_whole.pdf (5.888Mb)
    01_front.pdf (1.225Mb)
    Export to EndNote
    Abstract
    Chromium-containing fractions were isolated both from whole yeast cells and yeast extracts in attempts to isolate the glucose tolerance factor (GTF). Techniques for the isolation of chromium-containing fractions from whole yeast cells were investigated by first identifying the chromium fractions by means of chromium-51 labelling. An anionic complex was isolated from yeast cells which had been supplemented in a medium with high levels of chromium chloride. This complex was identified as a chromium-glucose complex but did not show any of the properties expected for the GTF. An isolation procedure based on ion-exchange chromatography achieved the isolation of eleven apparently discrete chromium-containing fractions from yeast extract. The activity determination of these fractions, by use of a yeast-fermentation assay, resulted in generally only the cationic fractions showing high activity levels. The origin of the isolated fractions was investigated by determining which fractions resulted from reaction with media components and those which probably resulted from association with yeast. These investigations showed that the majority of complexes formed were not synthesized by the yeast cells but were a result of reaction with media components. After these studies only two cationic fractions remained as possible candidates for the glucose tolerance factor. The cationic chromium-containing fractions from black peppercorns, sage, pork kidney powder, wheat bran and molasses were investigated. The cationic fractions obtained from these samples were identified as all having different ion-exchange elution positions and all having widely varying activities. Hence there did not appear to be a single discrete chromium-containing fraction which was capable of being identified with the glucose tolerance factor. Preincubation of chromium-deficient yeast in media containing chromium was undertaken in an attempt to demonstrate some requirement of the yeast for chromium. No such requirement could be demonstrated. On further purification of the active-cationic fractions the activity was shown to separate from the chromium but the factor causing the activity could not be identified. Collectively these results support the existence of a non-chromium containing factor, capable of increasing the rate of fermentation of yeast and hence a factor, which apart from the lack of a chromium atom, shows close similarity to the glucose tolerance factor as reported by Schwarz and Mertz.
    Date
    1981
    Author
    Haylock, Steven John
    Rights
    The Author
    Publisher
    Massey University
    URI
    http://hdl.handle.net/10179/3636
    Collections
    • Theses and Dissertations
    Metadata
    Show full item record

    Copyright © Massey University
    Contact Us | Send Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1
     

     

    Tweets by @Massey_Research
    Information PagesContent PolicyDepositing content to MROCopyright and Access InformationDeposit LicenseDeposit License SummaryTheses FAQFile FormatsDoctoral Thesis Deposit

    Browse

    All of MROCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Copyright © Massey University
    Contact Us | Send Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1