QUB-1985: a bioactive peptide from the frog skin secretion of Odorrana livida

  • Minxuan Liu

Student thesis: Masters ThesisMaster of Philosophy


Considering the severe problem of drug resistance developed by multiple pathogenic microorganisms, scientists have been working on developing novel therapeutic agents to replace conventional antibiotics. Antimicrobial peptides (AMPs), possessing broad-spectrum antimicrobial activity, have raised great interests among medical field for its potential bioactivity against bacteria, fungi, viruses and cancer cells and its multi-target mechanisms.

In this study, a cDNA encoding an AMP precursor was isolated and identified from the skin secretion of the wild green mountain frog, Odorrana livida, with the assistance of shotgun cloning. The obtained mature peptide consists of 21 amino acid residues, GLLSGILGVGKKIVCGLSGLC, and this peptide was named QUB-1985 according to its molecular mass. Afterwards, adequate peptides were acquired through SPPS, and several assays were carried out on QUB-1985 to determine its biological activities.

In antimicrobial assay, QUB-1985 exhibited potent antimicrobial activity against three model microorganisms, which are Staphylococcus aureus (Gram-positive bacteria), Escherichia coli (Gram-negative bacteria) and Candida albicans (fungi), and the MICs are 4, 8 and 16 μM respectively. Meanwhile, the cytotoxicity of QUB-1985 on horse red blood cells was rather low with a haemolysis of about 30% at the concentration up to 256 μM, which is more than 16-fold of the MICs against the three model microorganisms. In anticancer assay, however, no obvious anticancer activity was observed in QUB-1985 in this study.
Date of AwardJul 2018
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SupervisorChristopher Shaw (Supervisor) & Tianbao Chen (Supervisor)

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