Date of Award

Spring 2020

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

School

Biological, Environmental, and Earth Sciences

Committee Chair

Dr. Shahid Karim

Committee Chair School

Biological, Environmental, and Earth Sciences

Committee Member 2

Dr. Mohamed Elasri

Committee Member 2 School

Biological, Environmental, and Earth Sciences

Committee Member 3

Dr. Yanlin Guo

Committee Member 3 School

Biological, Environmental, and Earth Sciences

Abstract

Ticks are hematophagous ectoparasites that transmit a multitude of diseases to humans. Borrelia burgdorferi (BB) and Borrelia miyamotoi (BM) are both tick-borne pathogens that cause disease in humans and are transmitted by the black-legged tick (Ixodes scapularis). A byproduct of blood digestion generates reactive oxygen species that are toxic and cause oxidative stress which promotes cellular damage and dysfunction. The endoplasmic reticulum (ER) is especially affected by oxidative stress, resulting in a buildup of improperly folded proteins in the ER lumen called ER stress. To prevent cellular damage, the tick utilizes an antioxidant system to neutralize ROS and mechanisms to mitigate ER stress. There is very little to no research on BM and BB infection within the tick vector that contribute to understanding its molecular mechanism of survival within the tick before transmission to the mammalian host. The goal of this research is to elucidate the molecular determinants of vector competence to prevent tick-borne infectious diseases. We hypothesize that pathogen activation of tick ER stress mitigation pathways and antioxidant production in the black-legged tick facilitate BM and BB infection. To study the molecular determinants of Borrelia infection in Ixodes scapularis, we used a cell culture approach with the Ixodes scapularis embryonic cell line (ISE6) and analyzed temporal gene expression. Our results show that BMand BB infection causes upregulation of ERAD mitigation pathways and an upregulation of antioxidant production. This research provides insight into the tick-pathogen interaction of Ixodes scapularis and BB and BM.

Available for download on Friday, May 14, 2021

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