Campus Access Only

All rights reserved. This publication is intended for use solely by faculty, students, and staff of University of the Pacific. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, now known or later developed, including but not limited to photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author or the publisher.

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

Gregg Jongeward

Second Committee Member

Kirkwood Land


Pathogenesis attributable to infection with Trichomonas vaginalis , the causative agent of Trichomoniasis, is largely unknown although cysteine proteases have been implicated. This paper investigated the role of cysteine protease 4 (CP4) in T. vaginalis through characterization and expression of CP4. T. vaginalis strains showed differential protein and mRNA expression, although it was unclear which CP4 variants (other than TVAG_355480 and TVAG_467970) were recognized by the CP4 antibody for the protein studies. Iron did not regulate expression of TVAG_355480 and TVAG_467970 at the transcriptional but possibly at the post-transcriptional level. Our results also suggested that processing of recombinant TVAG_467970 occurred through cleavage by proteins rather than autocatalytic processing. Finally, endogenous CP4 was localized to vesicles though it was unclear which CP4 variant was recognized and was co-localized with HA-tagged VAMP1/2. Localization of HA-tagged TVAG_467970 proved problematic when co-staining with anti-HA and anti-CP4, so further localization studies need to be optimized. This paper also examined the role of iron superoxide dismutase 6 (TvFeSOD6) in resistance to metronidazole, the current drug used for Trichomoniasis infections. Of the two types of resistance, aerobic resistance may occur due to a high concentration of intracellular oxygen which can outcompete metronidazole for electrons or can re-oxidize reduced metronidazole to its inactive form. We determined that there was differential expression of TvFeSODs in T. vaginalis strains with varying levels of resistance although this may not correlate with the degree of resistance. Our results also showed that an increase in ectopic TvFeSOD6 in MSA1121 led to an augmentation in SOD activity and in resistance under aerobic conditions due to the possible role of TvFeSOD6 in also contributing to a higher intracellular oxygen concentration in MSA1121 (which is already sensitive to oxygen), leading to an increase in resistance.





To access this thesis/dissertation you must have a valid email address and log-in to Scholarly Commons.

Find in ProQuest



If you are the author and would like to grant permission to make your work openly accessible, please email


Rights Statement

Rights Statement

In Copyright. URI:
This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).