The discovery and functional study of an antimicrobial peptide QUB-1955 from the skin secretion of the northern orange-legged leaf frog, phyllomedusa hypochondrialis

Natural active substances extracted from skin secretions of anurans have attracted much interest in recent years. Among them, anti-bacterial peptides with broad-spectrum antibacterial activity have become promising drug candidates for the development of new antibiotics. <br><br>In this research, a bioactive peptide which belongs to the phylloseptin family, named QUB- 1955, was isolated from Phyllomedusa hypochondrialis skin secretions.

Initially, the mature peptide was identified from the cloned biosynthetic precursor encoding cDNA. Sufficient QUB-1955 was produced by solid-phase peptide synthesis and then, reverse phase high performance liquid chromatography (RP-HPLC) and matrix-assisted, laser desorption, ionisation, time-of-flight mass spectrometry (MALDI-TOF MS) were used to purify and confirm the structure of QUB-1955 for subsequent biological activity experiments (antimicrobial assays, anti-cancer cell assays and haemolysis assay). <br><br>In the order of potency, QUB-1955 had relatively potent antibacterial activity against Gram- positive bacteria (S. aureus), while it was weak against Gram-negative bacteria (E. coli), and had no activity against yeast (C. albicans).