• Login
    View Item 
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    •   Home
    • UA Graduate and Undergraduate Research
    • UA Theses and Dissertations
    • Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of UA Campus RepositoryCommunitiesTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournalThis CollectionTitleAuthorsIssue DateSubmit DateSubjectsPublisherJournal

    My Account

    LoginRegister

    About

    AboutUA Faculty PublicationsUA DissertationsUA Master's ThesesUA Honors ThesesUA PressUA YearbooksUA CatalogsUA Libraries

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Cryptosporidium oocyst viability: Assessment and correlation with infectivity.

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    azu_td_9322628_sip1_c.pdf
    Size:
    5.418Mb
    Format:
    PDF
    Download
    Author
    Korich, Dick Gary.
    Issue Date
    1993
    Keywords
    Dissertations, Academic.
    Microbiology.
    Committee Chair
    Sinclair, Norval A.
    
    Metadata
    Show full item record
    Publisher
    The University of Arizona.
    Rights
    Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
    Abstract
    Outbreaks of cryptosporidiosis have been traced to Cryptosporidium oocysts in finished drinking water. Indeed, water contaminated with oocysts may be judged perfectly safe by conventional coliform tests. Although oocysts can be specifically identified using immunofluorescence, it is not yet possible to determine their viability. The lack of a viability test means that each oocyst detected in finished water must be regarded as potentially infective even though water treatment may have killed them. The goal of this research was to develop a test for oocyst viability. In vitro excystation, oocyst morphology, vital dyes, and a monoclonal antibody were tested. In vitro excystation expressed as percent of theoretical sporozoite yield correlated best with neonatal mouse infectivity. Although not directly applicable to testing water samples, excystation provided a basis for screening other testing methods. None of the eight vital dyes tested showed any relationship between oocyst staining and viability. This was presumably due to inability of the dyes to penetrate the oocyst wall. Pretreatment strategies designed to increase oocyst wall permeability were either ineffective or damaged the oocysts in ways that rendered them nonviable. Initially, microscopic appearance appeared to be related to oocyst infectivity. However, regression analysis showed that phase contrast microscopic appearance had marginal utility for use as a viability test. Indeed, microscopic identification of internal structures of intact oocysts is not a reliable viability indicator because DAPI staining showed intact sporozoite nuclei within obviously dead oocysts that would not excyst. A monoclonal antibody (MAb OW64) was found which binds to internal sites along the oocyst suture. There was positive correlation between binding of this MAb and decreasing oocyst infectivity indicating that MAb OW64 bound preferentially to nonviable oocysts. Regression analysis showed that OW64 binding overestimated oocyst viability because many nonviable oocysts did not bind the MAb. Nevertheless, MAb OW64 is a candidate for producing an immunofluorescence based test in which oocysts that bind OW64 are nonviable whereas those that do not bind are not necessarily viable. Before such a test can be recommended, however, the nonviability of oocysts that bind OW64 must be demonstrated by neonatal mouse infectivity using oocysts sorted by a fluorescence activated cell sorter.
    Type
    text
    Dissertation-Reproduction (electronic)
    Degree Name
    Ph.D.
    Degree Level
    doctoral
    Degree Program
    Microbiology and Immunology
    Graduate College
    Degree Grantor
    University of Arizona
    Collections
    Dissertations

    entitlement

     
    The University of Arizona Libraries | 1510 E. University Blvd. | Tucson, AZ 85721-0055
    Tel 520-621-6442 | repository@u.library.arizona.edu
    DSpace software copyright © 2002-2017  DuraSpace
    Quick Guide | Contact Us | Send Feedback
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.