Identification, isolation and bioactivity assessment of a novel peptide from the skin secretion of Rana dybowskii

Amphibians skin secretion has been proved to have a variety of bioactive components, among which antimicrobial peptides (AMPs) are considered as the most potent ingredient. With the growing global problem of antibiotic resistance, AMPs have gradually entered the public’s field of vision and become an alternative therapeutic option to the traditional antibiotics.<br><br>In this research, a peptide precursor-encoding cDNA was cloned from the cDNA library of Rana dybowskii and named QUB-1188.

According to the sequence, the mature peptide region of QUB-1188 was synthesized, purified and identified by Solid-phase Peptide Synthesis (SPPS), reverse-phase High Performance Liquid Chromatography (RP-HPLC) and MALDI-TOF mass spectrometry (MS).<br>Results showed that QUB-1188 exhibited no significant inhibition on the growth of Gram-negative bacterium (Escherichia coli), Gram-positive bacterium (Staphylococcus aureus) and yeast (Candida albicans) up to the concentration of 512 μM. QUB-1188 didn’t show haemolytic activity up to the concentration of 512 μM. Also, the peptide showed no significant inhibition on the growth of human lung cancer cell line, NCI-H838 up to the concentration of 512 μM.<br><br><i>Thesis is embargoed until 31 December 2028.</i>