Abstract
The abuse of antibiotics has made drug resistance a problem in the field of infections worldwide. Compared with other small molecule drugs, Antibacterial peptides (AMPs) found in the secretions of amphibians have broad-spectrum antibacterial activity. In addition, AMP and antibiotics have different killing mechanisms, therefore, AMP may be promising for solving the antibiotic resistance.In this study, a novel peptide QUB-2791 was discovered from the skin secretion of Agalychnis anna using the "Shotgun" cloning, and then successfully synthesized by solid phase peptide synthesis. Reversed-phase high performance liquid chromatography (RP-HPLC) and Matrix-assisted laser desorption/ionisation Time-of-flight (MALDI-TOF) mass spectrometry （MS）were employed to obtain the purified peptides. Finally, a series of bioactivity studies using pure QUB-2791 showed that QUB-2791 has a strong inhibitory effect against the growth of Gram-negative bacteria Escherichia coli. The minimum inhibitory concentration of QUB-2791 is 64 μM, and the minimum bactericidal concentration is 128 μM. QUB-2791 showed broad-spectrum anticancer activity against human cancer cells H23, U251MG, H157, and PC3 with the IC50 values of 10.97 μM, 3.749 μM, 8.757 μM, and 15.69 μM, respectively. It is worth mentioning that QUB-2791 showed very low cytotoxicity against horse red blood cells at the concentration up to 512 μM. In conclusion, QUB-2791 is a novel bioactive peptide with potential clinical value, especially for the development of new anticancer therapies.
Thesis embargoed until 31st October 2024
| Date of Award | Dec 2019 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Tianbao Chen (Supervisor), Mei Zhou (Supervisor), Lei Wang (Supervisor) & Xinping Xi (Supervisor) |