Evaluation of bioactivity of QUB1977 from the skin secretion of the frog, Phyllomedusa camba

  • Xianhui Wu

Student thesis: Masters ThesisMaster of Philosophy


There are various bioactive peptides in the skin secretions of amphibians, which play an essential role in amphibian survival in consideration of the complicated natural and artificial factors. It is proven that many of these peptides exhibit antimicrobial, anticancer, antiviral and trypsin inhibitory activities and therefore their potential promising therapeutic value has drawn great attention from numerous researchers
In this study, a novel antimicrobial peptide was isolated and identified from the skin secretion of the frog, Phyllomedusa camba. A “shotgun” cloning technique was used to select the biosynthetic precursor sequence and a cDNA library was constructed for amplification of the target sequence. The peptide was isolated and identified using HPLC, MALDI-TOF mass spectrometry.
The synthetic replicate exhibited a broad spectrum antimicrobial activity against Gram-positive bacteria Staphylococcus aureus, Gram-negative bacteria Escherichia coli and the yeast Candida albicans at concentrations of 4, 32 and 4 µM, respectively. The haemolysis of this peptide was not significant at low concentrations but had a considerable increase at high concentrations. The concentration of the test peptide which induced 50% haemolysis (HC50) was 23 μM. The results indicated that the discovered peptide can be potential drug candidates for the design of new and valuable anti-infective agents.
Date of AwardJul 2017
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SupervisorChristopher Shaw (Supervisor), Tianbao Chen (Supervisor), Lei Wang (Supervisor) & Mei Zhou (Supervisor)

Cite this