Identification and functional assessment of a bioactive peptide QUB-2984 from the skin secretion of the red-eyed tree frog, Agalychnis callidryas

Bioactive peptides secreted from amphibians have been studied broadly for their potency as alternative drugs to treat human diseases. This thesis is about a caerin-related peptide derived from red-eyed leaf frog, Agalychnis callidryas, which provided ideas for further antibiotic research. Herein, the objectives included the isolation, identification, and bioactivity assessment of this bioactive peptide named QUB-2984. Agalychnis callidryas skin secretions were collected by stimulating the frogs’ skin. The sequence of QUB-2984 (GMWGTVFKGIKTVAKHLLPHVFSSQQS) was obtained by ‘shotgun’ cloning through constructing a cDNA library with isolated mRNA, and tested by DNA Sanger sequencing. It was synthesised by solid phase peptide synthesis, purified by reversed-phase high-performance liquid chromatography and structurally-confirmed by MALDI-TOF MS. The MIC value against gram-positive bacteria S.aureus was 2μM, gram-negative bacteria E.coli was 2μM, and against the pathogenic yeast C. albicans was 8μM. QUB-2984 showed anticancer potency at the minimum concentration of 10-5M towards human cancer cells. In terms of haemolysis, it caused around 50% haemolytic effect at 64μM. Its haemolytic effect implied the possibility of side-effects towards mammalian cells, but its ability to exert both antibacterial and anticancer biological activity makes this study valuable as a pre-study foundation for designing new antibiotics against cancer or infectious diseases. <br/><i><br/>Thesis embargoed until 31 December 2026</i>.

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

2021

Author dc:creator

• Tang, Ziyan

Advisors dc:contributor.advisor

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

• Antimicrobial peptides (AMPs)
• molecular cloning
• antimicrobial activity
• haemolytic activity
• MTT antiproliferation assay

Language dc:language

eng

Identifier

oai:pure.qub.ac.uk/portal:studenttheses/ad928ab9-d132-43e9-b5bd-d5c35c3e081f

OAI identifier oai:identifier

oai:pure.qub.ac.uk/portal:studenttheses/ad928ab9-d132-43e9-b5bd-d5c35c3e081f