Antimicrobial peptides secreted from amphibian skin secretions have many important bioactivities and act as the first line to defense against invading microorganisms. 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). In terms of MTT anticancer cell proliferation assays, QUB-2413 was proved to have no remarkable anticancer activities against U251-MG cells and HCT-116 cells in a range of concentration from 10 -6 M to 10 -4 M. With regard to haemolysis assay, QUB-2413 had no more than 10% haemolysis activity at 512 µM. Although the biological activities of QUB-2413 are not ideal, it is still expected to become a safe anti-positive bacteria drugs in the future after its antimicrobial activities get optimised through structural modification.
|Date of Award||Dec 2020|
- Queen's University Belfast
|Supervisor||Lei Wang (Supervisor)|