Discovery and functional study of the novel bioactive peptide QUB-1980 from the skin secretion of Odorrana grahami

Abstract

Nowadays, human health is threatened by antibiotic resistance, and a new effective antimicrobial strategy is needed to be found urgently. Antimicrobial peptides (AMPs) have been considered as novel promising candidates to replace antibiotics against these infections. In this report, the novel peptide QUB- 1980 was identified by using molecular cloning strategy, which shown a narrow bactericidal spectrum against tested strains. The bioactivity of QUB-1348V was compared with the parent peptide to study the significance of “Rana box” in the novel peptide QUB-1980. Besides, it also exhibited a mild toxicity to horse red blood cell. Besides, by substituting the “Rana box” with a C-terminal amide, a shorter AMP, QUB-1347NH2, was designed based on the natural peptide. As a result, QUB-1347NH2 was found to display weaker antimicrobial activity against Staphylococcus aureus (S. aureus) (ATCC CRM 6538), Escherichia coli (E. coli) (ATCC CRM 8739) and Candida albicans (C. albicans) (ATCC CRM 10231) than the natural peptide. Compared with natural peptide, QUB-1347NH2 showed better ability against Klebsiella pneumoniae (K. pneumoniae) (ATCC 43816) and C. albicans (ATCC CRM 10231). QUB-1980 and its analogues did not show antimicrobial activity against Pseudomonas aeruginosa (P. aeruginosa) (ATCC 9027), Methicillin-resistant Staphylococcus aureus (MRSA) (ATCC 12493) and Enterococcus faecalis (E. faecalis) (NCTC 12697).

Thesis embargoed until 31 December 2026.

Date of Award	Dec 2021
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Lei Wang (Supervisor), Mei Zhou (Supervisor), Tianbao Chen (Supervisor) & Xinping Xi (Supervisor)