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Date of Award


Document Type

Thesis - Pacific Access Restricted

Degree Name

Master of Science (M.S.)


Biological Sciences

First Advisor

Lisa Wrischnik

First Committee Member

Joan Lin-Cereghino

Second Committee Member

Craig Vierra


Trichomonas vaginalis is a protozoan parasite responsible for causing nearly eight million cases of Trichomoniasis every year in the United States. Trichomoniasis is often an asymptomatic infection, but in some cases it does lead to mild clinical manifestions. Trichomoniasis is easily treated with a single dose of Metronidazole. Drug resistance is not common, but it is on the rise. In addition to increasing rates of drug resistance, Trichomoniasis also poses a public health threat as it has been shown to increase the risk of HIV transmission. In order to combat this emerging public health threat, we must better understand the mechanism by which metronidazole exerts its action on T. vaginalis , as well as how the parasite has responded by evolving mechanisms of drug resistance on a molecular level. In order to investigate these questions, a microarray analysis of two distinct strains of T. vaginalis , one being more virulent and slightly less metronidazole sensitive, was performed. This allowed the identification of several genes that may play a role in virulence and drug susceptibility. Once these genes were identified, their differential regulation was further confirmed by Northern Blot analysis. One of these genes, Thioredoxin Reductase (TrxR) was then cloned and transfected into T. vaginalis . After confirming expression of the HA-tagged TrxR, the cell line was then used to determine the effect of over-expression of the gene on drug sensitivity. The metronidazole IC 50 for this cell line was compared to wild type cells. Additionally, immunostaining of the transfected cells was performed to determine the localization of the HA-tagged thioredoxin reductase. The results of this investigation provide further support for the role of TrxR in metronidazole activation as well as metronidazole sensitivity. Additionally, several other genes identified as differentially regulated may play a role in virulence, and should be targeted for further investigation.





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