Date of Award
12-2022
Degree Type
Thesis
Degree Name
Master of Science - Biology
Department
Biology
First Advisor
Dr. Dennis Gravatt
Second Advisor
Dr. Lindsay Porter
Third Advisor
Dr. Zeljko Radulovic
Fourth Advisor
Dr. Daniel Bennett
Abstract
Defensins are small, cysteine-rich, immune related proteins described to be the most widespread family of invertebrate antimicrobial peptides. Presently, there is limited information regarding spider defensins. In this study, a new defensin peptide was described in Latrodectus geometricus, Lg-defensin. The full open reading frame was resolved using RACE and de novo assembly, followed by a bioinformatical analysis and phylogenetic alignment to determine conserved sequence patterns and structural similarities to other defensins. Next, the functionality of Lg-defensin was determined using in vitro RNA interference to assess what impact silencing had on the spider’s ability to control a gram-positive and gram-negative bacterial infection, whose level was determined via qPCR analysis. Results indicated Lg-defensin to be a highly conserved defensin with similar structure and sequence patterns to other related taxa. Additionally, Lg-defensin was found to have higher antibacterial activity towards the gram-positive bacteria in contrast to its effect on gram-negative bacteria. This is the first report regarding the completed characterization of a defensin peptide in L. geometricus and provides a basis for future research regarding Lg-defensin and its clinically relevant capabilities.
Repository Citation
Thompson, Jacklyn Victoria, "Sequencing and functional characterization of a Latrodectus geometricus defensin, Lg-defensin" (2022). Electronic Theses and Dissertations. 477.
https://scholarworks.sfasu.edu/etds/477
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
