{"id":{"repo_id":"qu-belfast","oai_identifier":"oai:pure.qub.ac.uk/portal:studenttheses/cd4e451d-40cb-4057-845b-a86a2e81ac42"},"canonical_url":"https://search.dev.ndltd.org/etd/qu-belfast/oai:pure.qub.ac.uk/portal:studenttheses/cd4e451d-40cb-4057-845b-a86a2e81ac42","repository":{"repo_id":"qu-belfast","name":"Queen's University Belfast","base_url":"https://pureadmin.qub.ac.uk/ws/oai"},"display":{"title":"Identification and functional study of a bioactive peptide QUB-2007 from the skin secretion of the bicolour tree-frog Phyllomedusa bicolor","abstract":"Antimicrobial peptides secreted in amphibian skin secretions have many important bioactivities and act as the first line of defence against invading microorganisms. In this thesis, QUB-2007, a peptide belonging to the Phylloseptin family of the Dermaseptin superfamily, was derived from the skin secretion of Phyllomedusa bicolor. The peptide sequence was obtained by molecular cloning through constructing a cDNA library with isolated mRNA from frog skin secretion. The peptide was synthesised by solid phase peptide synthesis, purified using reversed-phase high performance liquid chromatography and structurally-confirmed by MALDI-TOF MS. In broth microdilution assays, QUB-2007 showed antimicrobial activities against the Gram-negative bacterium, Escherichia coli (E. coli ATCC CRM 8739), and the yeast, Candida albicans (C. albicans ATCC CRM 10231) at concentration of 32 μM, and the Gram-positive bacterium, Staphylococcus aureus (S. aureus ATCC CRM6538) at a concentration of 8 μM. In terms of MTT anticancer cell proliferation assays, QUB-2007 was shown to have anticancer activities against HCI-H838 lung cancer cells at a concentration of 10-4 M. With regard to haemolysis, QUB-2007 was haemolytic at concentrations of 32 μM could be 15%.<br/><br/>In conclusion, QUB-2007 has potential to be a drug, but its haemolytic activity is a big obstacle. It can be achieved by modifying the peptide, such as in changing certain amino acid sequences to change its cationicity, hydrophobicity and amphipathicity.<br/><br/><i>Thesis embargoed until 31 December 2026</i>.","abstract_html":"Antimicrobial peptides secreted in amphibian skin secretions have many important bioactivities and act as the first line of defence against invading microorganisms. In this thesis, QUB-2007, a peptide belonging to the Phylloseptin family of the Dermaseptin superfamily, was derived from the skin secretion of Phyllomedusa bicolor. The peptide sequence was obtained by molecular cloning through constructing a cDNA library with isolated mRNA from frog skin secretion. The peptide was synthesised by solid phase peptide synthesis, purified using reversed-phase high performance liquid chromatography and structurally-confirmed by MALDI-TOF MS. In broth microdilution assays, QUB-2007 showed antimicrobial activities against the Gram-negative bacterium, Escherichia coli (E. coli ATCC CRM 8739), and the yeast, Candida albicans (C. albicans ATCC CRM 10231) at concentration of 32 μM, and the Gram-positive bacterium, Staphylococcus aureus (S. aureus ATCC CRM6538) at a concentration of 8 μM. In terms of MTT anticancer cell proliferation assays, QUB-2007 was shown to have anticancer activities against HCI-H838 lung cancer cells at a concentration of 10-4 M. With regard to haemolysis, QUB-2007 was haemolytic at concentrations of 32 μM could be 15%.&lt;br/&gt;&lt;br/&gt;In conclusion, QUB-2007 has potential to be a drug, but its haemolytic activity is a big obstacle. It can be achieved by modifying the peptide, such as in changing certain amino acid sequences to change its cationicity, hydrophobicity and amphipathicity.&lt;br/&gt;&lt;br/&gt;&lt;i&gt;Thesis embargoed until 31 December 2026&lt;/i&gt;.","abstract_has_math":false,"creators":["Xu, Zixin"],"institution":"Queen's University Belfast","degree_name":"Master of Philosophy","degree_level":"Masters Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Zhou, Mei","Wang, Lei","Chen, Tianbao"],"committee_chairs":[],"committee_members":[],"year":2021,"date_issued":"2021-12","date_published":"2021-12","updated_at":"2026-07-24T03:56:04Z","subjects":["Antimicrobial peptides","antimicrobial activity","anti-proliferation activity","haemolytic activity","non-small lung cancer cell","phylloseptin"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:pure.qub.ac.uk/portal:studenttheses/cd4e451d-40cb-4057-845b-a86a2e81ac42"],"render_values":[{"text":"oai:pure.qub.ac.uk/portal:studenttheses/cd4e451d-40cb-4057-845b-a86a2e81ac42","href":null,"code":true}]}]},"links":{"outbound_url":"https://pure.qub.ac.uk/en/studentTheses/cd4e451d-40cb-4057-845b-a86a2e81ac42","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Zhou, Mei","Wang, Lei","Chen, Tianbao"]},{"key":"dc:creator","label":"Author","values":["Xu, Zixin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2021-12"]},{"key":"dc:date.issued","label":"Date","values":["2021-12"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["School of Pharmacy"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["Queen's University Belfast"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://pure.qub.ac.uk/en/studentTheses/cd4e451d-40cb-4057-845b-a86a2e81ac42"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Masters Thesis"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Master of Philosophy"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Antimicrobial peptides","antimicrobial activity","anti-proliferation activity","haemolytic activity","non-small lung cancer cell","phylloseptin"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights.embargodate","label":"Dc Rights Embargodate","values":["2026-12-31"]},{"key":"dc:rights.embargoreason","label":"Dc Rights Embargoreason","values":["/dk/atira/pure/core/document/studentthesisembargoreason/publicationissues"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:pure.qub.ac.uk/portal:studenttheses/cd4e451d-40cb-4057-845b-a86a2e81ac42","https://pure.qub.ac.uk/en/studentTheses/cd4e451d-40cb-4057-845b-a86a2e81ac42"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Antimicrobial peptides secreted in amphibian skin secretions have many important bioactivities and act as the first line of defence against invading microorganisms. In this thesis, QUB-2007, a peptide belonging to the Phylloseptin family of the Dermaseptin superfamily, was derived from the skin secretion of Phyllomedusa bicolor. The peptide sequence was obtained by molecular cloning through constructing a cDNA library with isolated mRNA from frog skin secretion. The peptide was synthesised by solid phase peptide synthesis, purified using reversed-phase high performance liquid chromatography and structurally-confirmed by MALDI-TOF MS. In broth microdilution assays, QUB-2007 showed antimicrobial activities against the Gram-negative bacterium, Escherichia coli (E. coli ATCC CRM 8739), and the yeast, Candida albicans (C. albicans ATCC CRM 10231) at concentration of 32 μM, and the Gram-positive bacterium, Staphylococcus aureus (S. aureus ATCC CRM6538) at a concentration of 8 μM. In terms of MTT anticancer cell proliferation assays, QUB-2007 was shown to have anticancer activities against HCI-H838 lung cancer cells at a concentration of 10-4 M. With regard to haemolysis, QUB-2007 was haemolytic at concentrations of 32 μM could be 15%.<br/><br/>In conclusion, QUB-2007 has potential to be a drug, but its haemolytic activity is a big obstacle. It can be achieved by modifying the peptide, such as in changing certain amino acid sequences to change its cationicity, hydrophobicity and amphipathicity.<br/><br/><i>Thesis embargoed until 31 December 2026</i>."]},{"key":"dc:title","label":"Title","values":["Identification and functional study of a bioactive peptide QUB-2007 from the skin secretion of the bicolour tree-frog Phyllomedusa bicolor"]}]}],"canonical_facts":{"dc:contributor.advisor":["Zhou, Mei","Wang, Lei","Chen, Tianbao"],"dc:creator":["Xu, Zixin"],"dc:date":["2021-12"],"dc:date.issued":["2021-12"],"dc:description.abstract":["Antimicrobial peptides secreted in amphibian skin secretions have many important bioactivities and act as the first line of defence against invading microorganisms. In this thesis, QUB-2007, a peptide belonging to the Phylloseptin family of the Dermaseptin superfamily, was derived from the skin secretion of Phyllomedusa bicolor. The peptide sequence was obtained by molecular cloning through constructing a cDNA library with isolated mRNA from frog skin secretion. The peptide was synthesised by solid phase peptide synthesis, purified using reversed-phase high performance liquid chromatography and structurally-confirmed by MALDI-TOF MS. In broth microdilution assays, QUB-2007 showed antimicrobial activities against the Gram-negative bacterium, Escherichia coli (E. coli ATCC CRM 8739), and the yeast, Candida albicans (C. albicans ATCC CRM 10231) at concentration of 32 μM, and the Gram-positive bacterium, Staphylococcus aureus (S. aureus ATCC CRM6538) at a concentration of 8 μM. In terms of MTT anticancer cell proliferation assays, QUB-2007 was shown to have anticancer activities against HCI-H838 lung cancer cells at a concentration of 10-4 M. With regard to haemolysis, QUB-2007 was haemolytic at concentrations of 32 μM could be 15%.<br/><br/>In conclusion, QUB-2007 has potential to be a drug, but its haemolytic activity is a big obstacle. It can be achieved by modifying the peptide, such as in changing certain amino acid sequences to change its cationicity, hydrophobicity and amphipathicity.<br/><br/><i>Thesis embargoed until 31 December 2026</i>."],"dc:identifier":["oai:pure.qub.ac.uk/portal:studenttheses/cd4e451d-40cb-4057-845b-a86a2e81ac42","https://pure.qub.ac.uk/en/studentTheses/cd4e451d-40cb-4057-845b-a86a2e81ac42"],"dc:language":["eng"],"dc:publisher.department":["School of Pharmacy"],"dc:publisher.institution":["Queen's University Belfast"],"dc:relation.isreferencedby":["https://pure.qub.ac.uk/en/studentTheses/cd4e451d-40cb-4057-845b-a86a2e81ac42"],"dc:rights.embargodate":["2026-12-31"],"dc:rights.embargoreason":["/dk/atira/pure/core/document/studentthesisembargoreason/publicationissues"],"dc:subject":["Antimicrobial peptides","antimicrobial activity","anti-proliferation activity","haemolytic activity","non-small lung cancer cell","phylloseptin"],"dc:title":["Identification and functional study of a bioactive peptide QUB-2007 from the skin secretion of the bicolour tree-frog Phyllomedusa bicolor"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["Masters Thesis"],"dc:type.qualificationname":["Master of Philosophy"]},"updated_at":"2026-07-24T03:56:04Z"}