Identification and functional study of a bioactive peptide, QUB-2315, from the skin secretion of Litoria caerulea

Abstract

With the misuse of traditional antibiotics, the problem of bacterial resistance is becoming increasingly severe. Frogs contain many bioactive molecules in their skin secretions, some of which are peptides with antimicrobial activity. In this study, peptide QUB-2315, identified in the dorsal skin secretion of the Australian green tree frog, Litoria caerulea, by molecular techniques and which belongs to the caerin family, was studied. A cDNA library was constructed by isolating the skin secretion poly-A mRNA and 'shotgun' cloning through which the amino acid sequence of QUB-2315 was obtained. QUB-2315 had no significant effect on Staphylococcus aureus (a Gram-positive bacterium) and Candida albicans (a yeast) and was only effective against Escherichia coli (a Gram-negative bacterium) at a concentration of 512 μM. Meanwhile, QUB-2315 was found to have no significant inhibitory effect on the proliferation of human lung adenocarcinoma cells NCI-H838, but it showed haemolytic activity (around 20% haemolysis) at 512 μM. Although the antibacterial and anticancer effects of QUB-2315 were not apparent, it has research value through potential, targeted modification of its primary structure.

Thesis embargoed until 31 December 2027

Date of Award	Dec 2022
Original language	English
Awarding Institution	Queen's University Belfast
Supervisor	Mei Zhou (Supervisor), Tianbao Chen (Supervisor) & Tao Wang (Supervisor)