A bioactive peptide, QUB-1813, from the defensive skin secretion of the Chinese Large Odorous Frog, Rana (Odorrana) livida
This thesis is focused on a study of the skin secretions from the Chinese Large Odorous frog, Odorrana livida. In this study, “shotgun” cloning was employed to identify a peptide named QUB-1813 from the skin secretion and online BLAST sequence analysis was also performed. The structure of the peptide was initially deduced from cloned precursor-encoding cDNA and confirmed by MALDI-TOF mass spectrometry. It was then chemically-synthesised by solid phase Fmoc chemistry to provide sufficient material to perform bioassays. The results showed that QUB1813 possessed weak antimicrobial activity against the standard Gram-negative bacterium, Escherichia coli (E. coli), the Gram-positive bacterium, Staphylococus aureus (S. aureus), and the yeast, Candida albicans (C. albicans). The peptide did not inhibit the proliferation of the human cancer cell lines, PC-3, H-157, MB-435s, and U251MG. Moreover, QUB1813 was likewise ineffective in modulating smooth muscle activity in preparations of rat bladder, ileum, uterus and tail artery. Further experiments, such as immunomodulatory tests and antidiabetic tests could be performed to search for a bioactivity for peptide QUB-1813.
Networked Digital Library of Theses and Dissertations