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Title page for ETD etd-09252014-105919


Type of Document Dissertation
Author Metcalf, Jason Andrew
Author's Email Address jason.andrew.metcalf@gmail.com
URN etd-09252014-105919
Title Evolutionary and Functional Studies of Wolbachia pipientis and its Phage
Degree PhD
Department Biological Sciences
Advisory Committee
Advisor Name Title
Patrick Abbot Committee Chair
Julian F. Hillyer Committee Member
Maureen A. Gannon Committee Member
Seth R. Bordenstein Committee Member
Keywords
  • cytoplasmic incompatibility
  • Archaea
  • horizontal gene transfer
  • lysozyme
  • phage WO
  • Wolbachia
Date of Defense 2014-09-22
Availability unrestricted
Abstract
Wolbachia pipientis is an obligate intracellular bacterium of increasing importance in understanding the tripartite interactions between viruses, bacteria, and eukaryotes, as well as having applications in modern medicine in the fields of antibacterial therapy and disease vector biocontrol. Four studies were undertaken to examine various aspects of Wolbachia biology. In the first investigation, an analysis of the evolution, horizontal transfer, and antibacterial activity of a lysozyme gene encoded by Wolbachia’s bacteriophage WO was undertaken. This study showed that the lysozyme had transferred across the tree of life to confer antibacterial traits to species in all domains. Secondly, a Wolbachia strain causing multiple reproductive manipulation phenotypes in its insect hosts was sequenced and unexpectedly found to contain a number of phage WO genes that could be causal for these manipulations. Third, transgenic Drosophila melanogaster were generated expressing these genes and their ability to cause cytoplasmic incompatibility was tested, demonstrating for the first time that WO genes can alter arthropod reproduction. Finally, the mechanisms of Wolbachia adaptation to novel hosts were analyzed through genome sequencing and culture of Wolbachia in two different species, Drosophila melanogaster and Aedes aegypti. It was discovered that Wolbachia undergoes minimal genetic change but substantial phenotypic change after host switching. These studies further our understanding of Wolbachia interactions with virus and host and may enable future use of Wolbachia and WO genes as therapeutics or in pest control strategies.
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