An antimicrobial peptide QUB-1925 from scorpion venom of Androctonus bicolor: molecular cloning of biosynthetic precursor-encoding cDNA and bioactivity study

  • Aoao Wang

Student thesis: Masters ThesisMaster of Philosophy

Abstract

Owing to the prominent biological diversity and potency, venoms of scorpion have attached to a starting point for drug discovery. This thesis focused on a novel antimicrobial peptide discovered from Androctonus bicolor. The QUB-1925 precursor-encoding cDNA was cloned by “shotgun” cloning of the venom-derived cDNA library, and the peptide was chemically synthesised by using the solid phase peptide synthesiser. Reverse phase high performance liquid chromatography (RP-HPLC) and LCQ Fleet ion-trap mass spectrometer were employed to purify the crude synthesised peptide and confirm the identity of this peptide, respevtively. Finally, the purified peptide was used to perform antimicrobial assays, haemolysis assay, and anti-tumour cell assays.

QUB-1925 presented inhibition effect on gram-positive bacteria, S. aureus, and gram-negative bacterium, E. coli, but little effect against the fungi, C. albicans. More importantly, QUB-1925 was found to induce a very low level of haemolysis at the minimal inhibitory concentration (MIC) of 8 μM ( against S.aureus) and 32μM (against E.coli), respectively. Moreover, QUB-1925 exhibited weak anti-proliferative activities against the human cancer cell lines PC-3, H-23, and U251MG. These data suggests that QUB-1925 has the potential to be a broad-spectrum antibiotic with low level of haemolytic activity. However, this cytotoxicity can not be ignorable. Future studies on the modification of AMP discovered from scorpion venom are therefore recommended.
Date of AwardDec 2019
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SupervisorTianbao Chen (Supervisor), Mei Zhou (Supervisor), Lei Wang (Supervisor) & Yuxin Wu (Supervisor)

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