Identification and bioactivity evaluation of a novel temporin peptide, QUB-1347, from the skin secretion of Rana dybowskii

Abstract

At present, many pathogenic microorganisms have developed serious resistance, so scientists are working to find a new type of treatment drugs to replace traditional antibiotics. Antimicrobial peptides (AMPs) have a broad spectrum of antibacterial activity and have attracted great interest from scientists because of their potential biological activities against bacteria, fungi, viruses and cancer cells.

In this study, shotgun cloning was utilized to isolate and identify a cDNA encoding an AMP precursor from the skin secretion of Rana dybowskii. The mature peptide that was obtained, FIGPIISALASLF-NH2, has 14 amino acid residues. Based on its molecular mass, this peptide was given the name QUB-1347. After sufficient peptides were obtained via SPPS, QUB-1347 was subjected to a number of tests to ascertain its biological activity.

In the antimicrobial assay, QUB-1347 showed significant antimicrobial activity only against Gram-positive bacteria, but not against Gram-negative bacteria and yeast. Staphylococcus aureus (Gram-positive bacterium), Escherichia coli (Gram-negative bacterium) and Candida albicans (yeast), had MICs of 16, >128 and >128 µM respectively. Meanwhile, QUB-1347 showed low cytotoxicity to equine red cells, it demonstrated haemolysis of less than 20% at 64 µM. Moreover, QUB-1347 had antiproliferative activity on H838 cancer cells, and the effect was significantly enhanced when the concentration was higher than 25 µM, and the IC50 was 18.65 µM.

Thesis is embargoed until 31 December 2029.

Date of Award	Dec 2024
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Lei Wang (Supervisor), Tianbao Chen (Supervisor) & Mei Zhou (Supervisor)