Identification and bio-evaluation of an antimicrobial peptide from the skin secretion of Phyllomedusa tarsius

Abstract

Antimicrobial peptides (AMPs), as a large classification of biologically active peptides, showed a broad-spectrum efficacy against various microorganisms. Although the antibacterial activity of these peptides already has been proven, studies have shown that antibacterial peptides can also play other roles. In this study, a novel peptide was identified from the skin secretion of the tree frog from South America, Phyllomedusa tarsius. After mRNA was isolated from skin secretions, a cDNA library was established and subjected to molecular cloning technology. The sequence of an active peptide, QUB-3128 (GLFKTLIKGAGKMLGHVAKQFLGSQGQPES) was deduced from the cloned cDNA encoding a dermaseptin precursor. Subsequently, this peptide was synthesised by solid-phase synthesis, and the purified synthetic form was used for biological assays. Results showed that this peptide possessed ideal inhibitory effects on S. aureus (NCTC 10788), E. coli (ATCC 8739) and C. albicans (ATCC 10231), with MIC concentrations of 4 µM, 8 µM and 128 µM, respectively. Also, it showed antiproliferative activities against two human cancer cell lines, H838 and PC-3, where the IC50 values against both were approximately 2 µM. However, this peptide demonstrated observable haemolytic effects at higher peptide concentrations (≥ 128 µM) on horse blood cells. Altogether, this dermaseptin peptide with antimicrobial and antiproliferative activity could be an ideal candidate for developing new antibacterial and anticancer reagents.

Date of Award	Dec 2020
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Mei Zhou (Supervisor), Xiaoling Chen (Supervisor), Lei Wang (Supervisor) & Tianbao Chen (Supervisor)