AbstractFrog skin is characterised with an abundance of biologically active antimicrobial peptides (AMPs) with a broad-spectrum effect against a variety of microorganisms. The contribution of their complex and diverse structures, physicochemical properties and mechanisms of biological activity, have been discovered and widely reported. In this study, a novel peptide named QUB-1923 was identified from the skin secretion of the Senegal running frog, Kassina senegalensis. The sequence of the mature peptide (FYHLSALIHGIKQRLK) was deduced from the cloned cDNA encoding a prepropeptide. Subsequently, this peptide was chemically synthesised by solid-phase synthesis. Following on from the purification by RP-HPLC and MALDI-TOF MS, the antimicrobial, anti-cancer cell proliferative and haemolytic activities of the purified peptide QUB-1923 were investigated. Results from antimicrobial assays have shown that this peptide has a broad-spectrum antimicrobial effect on S. aureus, E. coli and C. albicans. Notably, this peptide displayed the highest antimicrobial activity against E. coli (MIC=4 μM, and MBC=8 μM). On the other hand, this peptide only caused approximately 20% growth inhibition on lung cancer cell line H838 at a concentration of 100 μM. Additionally, this peptide demonstrated less than 10% haemolysis at a concentration of 256µM. These results suggest that this novel peptide is worthy of attention as a new antibacterial lead due to its potent inhibitory and bactericidal effects against Gram-ve bacteria, along with a low level of haemolysis.
Thesis embargoed until 31 December 2026.
|Date of Award||Dec 2021|
|Supervisor||Mei Zhou (Supervisor), Lei Wang (Supervisor), Tianbao Chen (Supervisor) & Xiaoling Chen (Supervisor)|
- Antimicrobial peptide
- bioactivity assessment
- broad-spectrum antimicrobial activity
- low haemolysis activity
- novel peptide