AbstractDue to the increased and inappropriate use of antibiotics, antibiotic resistance has emerged and become a global threat during the past decades. As the problem of antibiotic resistance gets worse, the need to search for novel antimicrobial molecules is high on the agenda. Antimicrobial peptides (AMPs) derived from amphibian defensive skin secretions have been found to possess remarkable bioactivities in some areas, such as antimicrobial activities, smooth muscle activities, anticancer activities, and so on. Therefore, AMPs are now recognised as one of the most promising groups of molecules for potential therapeutic applications in the future.
This thesis aimed to isolate and identify the structure of a bioactive peptide from the skin secretion of the Chinese bamboo leaf odorous frog, Odorrana versabilis, by applying ‘shotgun’ molecular cloning technology. After this was achieved, the synthetic peptide replicate obtained using solid phase peptide synthesis, was identified and purified by reverse phase high performance liquid chromatography (RP-HPLC) and mass spectrometry. Afterwards, an array of assays was carried out to assess the bioactivities of the peptide.
Indeed, a peptide, named QUB-2040, was isolated and found to possess antimicrobial activity against S. aureus, E. coli and C. albicans with minimum inhibitory concentrations (MICs) of 8 µM, 16 µM, and 8 µM, respectively. In addition, the peptide QUB-2040 was found to cause less than 30% lysis of the horse erythrocytes at effective concentrations. Nevertheless, QUB-2040 showed no inhibitory effects on the proliferation of the tested four cancer cells. Therefore, it has the potential to be developed as a promising antimicrobial drug in the future study.
|Date of Award
|25 Aug 2017
|Tianbao Chen (Supervisor), Lei Wang (Supervisor), Xinping Xi (Supervisor) & Mei Zhou (Supervisor)