Theses and Dissertations from UMD

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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

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Author: search.filters.author.Rodgers, Mark Andrew

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    A DNA REPAIR/PHASE VARIATION REPORTER SYSTEM USING A POLY-GUANINE TRACT IN A NEISSERIA GONORRHOEAE NITROREDUCTASE GENE
    (2005-11-10) Rodgers, Mark Andrew; Stein, Daniel C; Cell Biology & Molecular Genetics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Neisseria gonorrhoeae undergoes phase variation to adapt to new environments, increase pathogenesis, and evade the host immune system. This may be due to defects in DNA repair. A reporter system was created to detect phase variation by phenotypic switching from a nitrofuran-sensitive phenotype to a nitrofuran-resistant (NitR) phenotype. Strains were created with poly-guanine tracts from 5 to 12 guanines in the coding region of a nitroreductase gene (nfsB) that would be susceptible to frame-shifting mutations during DNA replication. The minimum number of consecutive guanines needed to observe increased mutation was 5. A strain expressing 7 guanines nfsB possessed nitroreductase activity similar to wild-type and a spontaneous mutation frequency that was increased ~104 fold relative to wild-type. Frame-shifting mutations of strain expressing 8 guanines in nfsB were observed using denaturing gradient gel electrophoresis (DGGE). Future work with the reporter system could lead to new understanding of phase variation and DNA repair.