Date of Award

5-2021

Degree Type

Honors College Thesis

Academic Program

Biological Sciences BS

Department

Biological Sciences

First Advisor

Shahid Karim, Ph.D.

Advisor Department

Biological Sciences

Abstract

The lone star tick Amblyomma americanum is a vector of various disease-causing pathogens and tick-borne alpha-gal syndrome (AGS) with rapidly expanding populations in the south- and northeast regions of the United States. This study aimed to molecularly characterize galectin and determine its involvement in galactose-α-1,3-galactose (α-gal) synthesis, transport, reproductive fitness, and microbial homeostasis in this tick. The lone star tick galectin possesses two conserved carbohydrate recognition domains and shares homology with other Ixodid tick galectins. Time and tissue-dependent expression data shows that galectin is constantly expressed in salivary glands, midgut, and ovary tissues. An RNA interference approach was used to silence galectin gene expression and assess its functional consequences on tick galactose-metabolism, reproductive fitness, and microbial homeostasis. Depletion of galectin gene expression resulted in the downregulation of galactose-metabolism genes, but no significant reduction in levels of α-gal. Intriguingly, Galectin-silenced ticks showed impaired oviposition and increased microbial load in tick salivary gland and midgut tissue, indicating its potential role in tick immunity and microbial homeostasis. Together, these data provide valuable insight on tick physiology and may provide information that helps elucidate the onset of α-gal syndrome.

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