Molecular cloning and functional investigation of a novel antimicrobial peptide, QUB-1348, from the skin secretion of the spiny frog, Hylarana spinulosa

Using a Tribute peptide synthesiser, QUB-1348 was synthesised and MALDI-TOF mass spectrometry was used to confirm its molecular mass. <br><br>Tests for haemolysis, antiproliferation, and antibacterial properties were among the several assays used to evaluate the bioactivities of pure QUB-1348. QUB-1348 showed strong antibacterial action in tests against three model microorganisms: the Gram-positive bacterium, Staphylococcus aureus, the Gram-negative bacterium, Escherichia coli, and the yeast, Candida albicans.

The relative MICs were 4 µM, 8 µM, and 32 µM. Furthermore, QUB-1348 has obvious hemolytic activity above the concentration of 32 μm. MTT assay showed that QUB-1348 had anti-proliferation effect on H-838 lung cancer cells, and the average IC50 was 21.36 μM. This indicates that QUB-1348 is still toxic to human cells, but it has obvious antibacterial and anti-proliferative activities. It is hoped that future drug research can apply its biological activity, and reduce its toxicity, so that it can be used in the clinic.<br><br><i>Thesis is embargoed until 31 December 2029.</i><br>