A bioactive peptide QUB3009 from the defensive skin secretion of the frog, Phyllomedusa tomopterna
The frog skins are biochemical, morphological and physiological organs, which play many significant roles in frog survival. Frog skin secretions contain bioactive components which include biogenic amines, alkaloids, peptides and proteins. Antimicrobial peptides from frog skin secretions display vital broad-spectrum antimicrobial activity and have been promoted for the research of novel chemical drugs. In this thesis, an antimicrobial peptide from the defensive skin secretion of the tiger leg monkey tree frog (Phyllomedusa tomopterna), ALWKDLLKNVGIAAGKAVLNKVTDMVNQ-NH2, has been isolated and identified by using “shotgun” molecular cloning of biosynthetic precursor-encoding cDNA and MALDI-TOF MS. Additionally, solid phase peptide synthesis was used for synthesis of the peptide. The synthetic replicate was subjected to functional assays, including antimicrobial assays, haemolysis assays and anticancer cell assays. The peptide was demonstrated to have antimicrobial activity against S. aureus, E. coli and C. albicans at concentrations of 64, 64 and 32 µM, respectively. In conclusion, the peptide QUB3009 has significant antimicrobial activity. There is no significant haemolytic activity of QUB3009, there is no significant anticancer activity of QUB3009.
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