Identification and functional study of an antimicrobial peptide, QUB 3378, isolated from the skin secretion of Hylarana spinulosa

The focus here is on the peptide named QUB-3378 from the skin secretions of the Spiny frog, Hylarana spinulosa. This AMP belongs to the Brevinin-2 family.<br><br>The sequence was first determined by molecular cloning, then the peptide was synthesized by solid-phase synthesis and was purified using reversed-phase high performance liquid chromatography (RP-HPLC), analysed by MALDI-TOF MS, and finally biologically assessed.

Peptide QUB-3378 had broad spectrum antimicrobial activity and could kill S. aureus NCTC 10788, and E. coli NCTC 10418, with MICs of 2 µM, 4 µM. The QUB-3378 has no effect to against C. albicans ATCC 10231. It was also very active against cancer cells and IC50 of QUB-3378 against lung cancer cell line NCI-H838 (Human Non-small Cell Lung Cancer) is 3.17 μM. With regard to haemolysis, QUB-3378 had no more than 20% haemolysis activity at 16 µM. Although the haemolytic activity was less than optimal, the peptide could potentially be modified and optimized to achieve better outcomes.<br><br><i>Thesis is embargoed until 31st December 2029</i>.<br>