• Login
    View Item 
    •   SMARTech Home
    • Georgia Tech Theses and Dissertations
    • Georgia Tech Theses and Dissertations
    • View Item
    •   SMARTech Home
    • Georgia Tech Theses and Dissertations
    • Georgia Tech Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Genetic Identification of Reductive Dehalogenase Genes in Dehalococcoides

    Thumbnail
    View/Open
    krajmalnik-brown_rosa_200508_phd.pdf (3.104Mb)
    Date
    2005-07-20
    Author
    Krajmalnik-Brown, Rosa
    Metadata
    Show full item record
    Abstract
    Chloroethenes such as tetrachloroethene (PCE), trichloroethene (TCE), dichloroethene (DCE) and vinyl chloride (VC), are major contaminants in subsurface systems threatening water quality and human health. Under anaerobic conditions, PCE and TCE can be reductively dechlorinated to ethene. Recent findings indicate that members of the Dehalococcoides group are responsible for ethene formation at chloroethene-contaminated sites. Dehalococcoides species exhibit diverse dechlorination activities, but share highly similar 16S rRNA genes. Hence, additional gene targets that go beyond the 16S rRNA gene are needed to reliably detect and quantify Dehalococcoides populations involved in high rate chloroethene detoxification at contaminated sites. Dehalococcoides sp. strain BAV1 couples growth to reductive dechlorination of VC to ethene. To shed light on the genes involved in reductive dechlorination in strain BAV1, degenerate primers targeting reductive dehalogenase (RDase) genes of Dehalococcoides were designed using available sequence information. PCR amplification with these primers yielded seven putative RDase genes with genomic DNA from strain BAV1 as template. Transcription analysis identified one RDase gene possibly involved in VC dechlorination, which was named bvcA. The bvcA gene was not present in Dehalococcoides strains that failed to couple growth with reductive dechlorination of VC (i.e., Dehalococcoides isolates CBDB1, FL2 and 195). Primers specific for bvcA detected this gene in several, but not all, Dehalococcoides-containing, ethene-producing mixed cultures. Apparently, the bvcA-targeted primers do not capture the diversity of VC RDase genes. Nevertheless, a relevant target was identified, and bvcA-targeted primers are commercially applied to monitor Dehalococcoides sp. strain BAV1 and related organisms at contaminated sites undergoing bioremediation treatment. Additional RDase genes were identified in Dehalococcoides sp. strain FL2, and expression analysis was performed when FL2 was grown with cis-DCE and TCE as electron acceptors. Multiple RDase genes were transcribed with each electron acceptor. This work identified novel process-specific target genes that are useful for site assessment and bioremediation monitoring at chloroethene-contaminated sites. In particular, bvcA emerged as a relevant target for monitoring the critical detoxification step from VC, to ethene. Additionally, the RDase genes retrieved in this work form a basis for further exploration of the specific functions and regulation mechanisms involved in reductive dechlorination processes.
    URI
    http://hdl.handle.net/1853/11642
    Collections
    • Georgia Tech Theses and Dissertations [23877]
    • School of Civil and Environmental Engineering Theses and Dissertations [1755]

    Browse

    All of SMARTechCommunities & CollectionsDatesAuthorsTitlesSubjectsTypesThis CollectionDatesAuthorsTitlesSubjectsTypes

    My SMARTech

    Login

    Statistics

    View Usage StatisticsView Google Analytics Statistics
    facebook instagram twitter youtube
    • My Account
    • Contact us
    • Directory
    • Campus Map
    • Support/Give
    • Library Accessibility
      • About SMARTech
      • SMARTech Terms of Use
    Georgia Tech Library266 4th Street NW, Atlanta, GA 30332
    404.894.4500
    • Emergency Information
    • Legal and Privacy Information
    • Human Trafficking Notice
    • Accessibility
    • Accountability
    • Accreditation
    • Employment
    © 2020 Georgia Institute of Technology