Date of Award
Master of Science - Biology
Dr. Dennis Gravatt
Dr. Lindsay Porter
Dr. Zeljko Radulovic
Dr. Daniel Bennett
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.
Thompson, Jacklyn Victoria, "Sequencing and functional characterization of a Latrodectus geometricus defensin, Lg-defensin" (2022). Electronic Theses and Dissertations. 477.
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