A bioactive peptide, QUB-2048, from the defensive skin secretion of Phyllomedusa tomopterna

Amphibian skin is a biochemically, morphologically and physiologically complex organ which is responsible for the survival and defence of amphibians. Amphibian skin secretion is deemed as a reservoir of bioactive compounds and antimicrobial peptides (AMPs) are among the most attractive of these. Due to antibiotic resistance and the eager need of developing new types of anti-infective drugs, such peptides are considered as an alternative therapeutic option due to their potent broad-spectrum antimicrobial activity. Thus, AMPs are arousing great attention in pharmaceutical and biotechnical fields.<br/>In this study, a ‘shotgun’ cloning procedure was employed to construct a skin secretion-derived cDNA library. A peptide precursor-encoding cDNA was successfully cloned from such a library of the tiger-legged monkey tree frog, Phyllomedusa tomopterna, and named QUB-2048. Subsequently, the predicted mature peptide, named QUB-2048 was isolated and identified by reverse-phase HPLC and MALDI-TOF mass spectrometry, and then chemically-synthesised by solid-phase peptide chemistry to facilitate assessment of bioactivity.<br/>QUB-2048 was found to have potent antimicrobial activity against the yeast, Candida albicans and the Gram-positive bacterium, Staphylococcus aureus, against both of which the peptide displayed a minimum inhibitory concentration (MIC) of 4 µM, while displaying a comparatively less potent effect on the Gram-negative bacterium, Escherichia coli with an MIC of 32 µM. QUB-2048 also showed 20% lower haemolytic activity at a concentration of 32 µM compared to Triton X-100. However, it exhibited no effect on the selected human cancer cell lines, U251MG, MB435, H157, and PC3. <br/>

Name dc:type.qualificationname

Master of Philosophy

Level dc:type.qualificationlevel

Masters Thesis

Grantor dc:publisher.institution

Queen's University Belfast

Year dc:date.issued

2017

Author dc:creator

• Dong, Bowen

Advisors dc:contributor.advisor

• Chen, Tianbao
• Wang, Lei
• Zhou, Mei

Language dc:language

eng

Identifier

oai:pure.qub.ac.uk/portal:studenttheses/37f119b0-440b-420a-ae34-aaf8b8adc03c

OAI identifier oai:identifier

oai:pure.qub.ac.uk/portal:studenttheses/37f119b0-440b-420a-ae34-aaf8b8adc03c