: A novel peptide with antimicrobial activities from the skin secretion of Phyllomedusa tarsius

  • Qinrong Zhou

Student thesis: Masters ThesisMaster of Philosophy


So far, the abuse of antibiotics caused their effectiveness decreased rapidly. Because of these problems, the new source should be discussed as a necessity. Antimicrobial peptides are small molecules with activity against bacteria, yeasts, fungi, viruses, bacteria, and even tumour cells. On the other hand, antimicrobial peptides are considered as an essential product of amphibian skin secretions, the skin secretion of amphibian is a rich source of biologically active compounds that are assumed to have diverse physiological and defence functions.
One novel dermseptin peptide was identified from Phyllomedusa tarsius by molecular cloning which is named QUB-3170. Another peptide was amidated from it named QUB-2987. Then the mature peptides were successfully synthesised by solid phase peptide synthesiser. RP-HPLC was used for purification and MALDI-TOF MS was use to confirm the molecular mass. They were tested for their anticancer, antimicrobial,
haemolysis activity.
The results of the research showed that it was an activity to Gram-positive,Gram-negative bacteria and fungi. The MIC of QUB-3170 and QUB-2987 to S. aureus, E. Coli and C. albicans was at 8, 4, 32 μM, 8, 8, 32 μM, the MBC of QUB-3170 and QUB-2987 to S. aureus and E. Coli was at 8, 16 μM, 16, 16μM. However, they both showed no effect on MBC of C. albicans. Meanwhile, both of them showed strong haemolysis activity at HC50 of 31.36 μM and 30.25 μM. The anticancer activity showed that QUB-3170 was active to H157 cancer cells with IC50 of 7.94μM, QUB-2987 was active to MCF-7 cancer cells with IC50 of 9.12μM. In this study, we discovered one novel antimicrobial peptide, one peptide modified from it, which may contribute to the future clinic peptide study.
Date of AwardJul 2018
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SupervisorChristopher Shaw (Supervisor), Tianbao Chen (Supervisor), Xinping Xi (Supervisor) & Chengbang Ma (Supervisor)

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