Identification and functional study of a bioactive peptide QUB-2413 from the skin secretion of the Red-Eyed Tree Frog, Agalychnis callidryas

In this thesis, QUB-2413, a peptide belonging to the plasticins family of the dermaseptins superfamily, was derived from the skin secretion of the Central American Red-eyed Leaf Frog, Agalychnis callidryas. The peptide sequence was obtained by molecular cloning through constructing a cDNA library with isolated mRNA from frog skin secretion.

The peptide was synthesised by solid phase peptide synthesiser, purified using reversed-phase high performance liquid chromatography and confirmed by MALDI-TOF. In broth microdilution assays, QUB-2413 showed no significant antimicrobial activities against the Gram-negative bacterium, Escherichia coli (E. coli ATCC CRM8739), and the yeast, Candida albicans (C. albicans ATCC CRM10231) at concentration of 512 µM, while it had inhibitory effects on the Gram-positive bacterium, Staphylococcus aureus (S. aureus ATCC CRM6538).