AbstractScorpion venom contains a variety of peptides exerting broad bioactivities. In this thesis, QUB-1761, a non-disulphide bridged peptide (NDBP), was discovered in the venom of the Brazilian yellow scorpion, Tityus serrulatus (T. serrulatus). The peptide was identified through molecular cloning by using a sense primer. The synthetic peptide was obtained by solid phase peptide synthesis (SPPS), followed by purification and confirmation through reversed-phase high performance liquid chromatography (RP-HPLC) and matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS). In broth microdilution assays, QUB-1761 had strong inhibitory effects on both Gram-positive and Gram-negative bacteria (MIC=8 µM for Staphylococcus aureus, MIC=32 µM for Escherichia coli). However, it was of low potency against yeast (MIC=128 µM for Candida albicans). In MTT anticancer cell proliferation and trypan blue exclusion assays, QUB-1761 beyond the concentration of 40 µM can completely kill the human lung cancer cells (NCI-H838). In terms of the haemolytic assays, QUB-1761 showed about 30% haemolysis activity at 64 µM and more than 50% at 128 µM. Nonetheless, QUB-1761 has the potential to be used in the design of drugs to treat bacterial infections or cancer if optimised.
Thesis embargoed until 31 December 2022.
|Date of Award||Dec 2021|
|Sponsors||Queen's University & China Scholarship Council|
|Supervisor||Mei Zhou (Supervisor), Tianbao Chen (Supervisor), Lei Wang (Supervisor) & Yuan Ying (Supervisor)|
- Scorpion venom
- non-disulphide bridged peptide
- Gram-positive and Gram-negative bacteria
- human lung cancer
- haemolysis activity