AbstractPolypeptides in amphibian skin secretions have various bioactive functions, especially the positively-charged, alpha-helical and amphipathic polypeptides. In this study, a novel antimicrobial peptide isolated from the skin secretions of Rana catesbeiana was named QUB-1368. After establishing the cDNA library, the biosynthetic precursor was obtained through molecular cloning, and then the mature peptide QUB-1368 was deduced from the precursor. QUB-1368 was then obtained in quantity by solid-phase peptide synthesis for biological activity experiments. The purified synthetic peptide QUB-1368 was identified by reversed-phase high-performance liquid chromatography (HPLC) and Matrix-Assisted Laser Desorption/ Ionization Time of Flight Mass Spectrometry (MALDI-TOF). In this study, QUB-1368 showed a broad-spectrum antibacterial activity to Gram-negative bacteria (64 µM against E. coli ATCC CRM 8739), Gram-positive bacteria (32 µM against S. aureus ATCC CRM 6538) and yeast (64 µM against C. albicans ATCC CRM 10231). In addition, in the concentration range of 102-10-3 µM, QUB-1368 has no inhibitory effect on the human lung cancer cell line (H838). In the haemolysis assay, QUB-1368 showed haemolytic activity at a concentration of 256 µM, when QUB-1368 showed antibacterial activity, the concentration did not reach to produce hemolysis. In summary, QUB-1368 may have good clinical research value.
Thesis embargoed until 31 December 2026.
|Date of Award||Dec 2021|
|Supervisor||Mei Zhou (Supervisor), Lei Wang (Supervisor), Tianbao Chen (Supervisor) & Xinping Xi (Supervisor)|
- Antimicrobial peptides
- bioactivity evaluation
- antimicrobial activity
- haemolytic activity
- temporin peptides