QUB-2825: A novel bioactive peptide from the skin secretion of Phyllomedusa hypochondrialis

  • Lingling Liu

Student thesis: Masters ThesisMaster of Philosophy


Amphibian skin secretions contain large amounts of bioactive molecules, especially antimicrobial peptides (AMPs), which has drawn great attention of researchers. Due to their potential as alternative candidates for the treatment of multi-drug resistance microbes. The dermaseptins consist of a superfamily within amphibian AMPs, which also possess anticancer activities with weak haemolytic effect.

My research aims at searching for a novel bioactive peptide from the skin secretion of the Northern Orange-legged Leaf Frog Phyllomedusa hypochondrialis using molecular cloning. According to the obtained sequence, target peptide was synthesised by solid phase peptide synthesiser and purified by RP-HPLC. The product peptide was then identified by MALDI-TOF. At last, the synthesised peptide was used to test for its biological functions including antimicrobial, anticancer and haemolytic activities.

A 28 amino-acid-residue novel peptide QUB-2825, whose sequence is ALWKSLLKNVGVAAGKAALNAVTGMVNQ-NH2, which belongs to the dermaseptin superfamily, was discovered in the skin secretion of Phyllomedusa hypochondrialis. The results of the research showed that QUB-2825 possesses killing effect against Gram-positive, Gram-negative bacteria, and fungi. The MICs of QUB-2825 against Escherichia coli, Staphylococcus aureus, and Candida albicans are 4,8, and 32 μM, respectively. Meanwhile, this peptide showed vigorous anticancer activities against H157, PC-3, and U251MG, the IC50 of QUB-2825 against which are 1.9, 18, and 16 μM. The haemolytic effect of QUB-2825 showed no significant value at 64 μM or less compared to the vehicle control.

Thesis embargoed until 31st October 2024
Date of AwardDec 2019
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SupervisorTianbao Chen (Supervisor), Mei Zhou (Supervisor), Lei Wang (Supervisor) & Chengbang Ma (Supervisor)

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