The discovery of a novel dermaseptin identified from the defensive skin secretion of the South American frog, Phyllomedusa sauvagii

Abstract

Due to the evolving drug resistance of pathogens, it is necessary to develop novel antibiotics. Through decades of investment, peptides have been proven to be one potential group of biologics that may contribute to the development of new antibiotics as they combine the advantages of both small molecule medicines and therapeutic proteins.
Through molecular cloning, the cDNA sequence encoding a new antimicrobial peptide (AMP), named QUB-2593, has been identified in the skin secretion of Phyllomedusa sauvagii. The novel peptide was synthesised using Solid Phase Peptide Synthesis technology. After the identification/authentication of the synthetic replicate of QUB-2593 by High Performance Liquid Chromatography (HPLC) and Matrix-assisted, laser desorption, ionisation, time-of-flight (MALDI-TOF) mass spectrometry, QUB-2593 was subjected to functional tests and it was found to have potent antimicrobial effects against E. coli (MIC = 4 µM; MBC = 32 µM), S. aureus (MIC = 32 µM; MBC = 512 µM), and C. albicans (MIC = 32 µM; MBC = 256 µM). Meanwhile, its haemolytic activity on horse erythrocytes was rather low being only 20.6% at 512 µM. The selective antimicrobial effects observed would indicate that QUB-2593 might deserve further exploration.
It is expected that this study will contribute to the finding of novel AMPs and the design of novel antibiotics.

Date of Award	Dec 2017
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Tianbao Chen (Supervisor), Lei Wang (Supervisor), Lei Li (Supervisor) & Mei Zhou (Supervisor)