It is well-known that natural sources have provided humans with various drugs, for example, penicillin which has saved a large number of lives. The skin secretions of amphibians contain a large number of bioactive compounds, such as peptides, alkaloids and sterols. Some compounds have been demonstrated to have therapeutic potential.
In this thesis, a novel antimicrobial peptide, named QUB-1463, was isolated and identified in the secretions of the Chinese brown frog, Rana chensinensis. Via "shotgun" molecular cloning, the biosynthetic precursor sequence of QUB-1463 was obtained. Afterwards, RP-HPLC and MALDI-TOF-MS were employed to double confirm the primary structure of this novel peptide. The mature peptide was synthesised via solid phase peptide synthesis and subjected to minimal inhibitory concentration (MIC) assay using different microorganisms, MTT assay using different kinds of cancer cell lines, and haemolytic activity assay using horse red blood cells. The results
obtained from three individual experiments showed that QUB-1463 did not exhibit antimicrobial activity against S. aureus, E. coli and C. albicans even at the highest concentration and the MIC of QUB-1463 was > 512 μM.. The anticancer activity of this peptide was extremely weak. QUB-1463 showed significant inhibition to H157, PC3 and H23 cell lines only at the highest concentration of 10-3 M and showed no significant effect against U251-MG cell line even at the highest concentration. The IC50 of QUB-1463 against H157, PC3 and H23 was 1761 μM, 1860 μM and 2846 μM, respectively. However, QUB-1463 showed no haemolysis activity even at the highest concentration 512μM. Although QUB-1463 has no antimicrobial effect and extremely weak anticancer effect, regarded as a novel bioactive peptide, it is still worthy for further study on other functions.
|Date of Award||Dec 2019|
- Queen's University Belfast
|Supervisor||Tianbao Chen (Supervisor), Mei Zhou (Supervisor), Lei Wang (Supervisor) & Chengbang Ma (Supervisor)|