{"id":{"repo_id":"qu-belfast","oai_identifier":"oai:pure.qub.ac.uk/portal:studenttheses/c0d5d8a7-6ca3-471f-8e58-1b530a5092e2"},"canonical_url":"https://search.dev.ndltd.org/etd/qu-belfast/oai:pure.qub.ac.uk/portal:studenttheses/c0d5d8a7-6ca3-471f-8e58-1b530a5092e2","repository":{"repo_id":"qu-belfast","name":"Queen's University Belfast","base_url":"https://pureadmin.qub.ac.uk/ws/oai"},"display":{"title":"QUB-1157: a bioactive peptide from the skin secretion of the Mexican leaf frog (Pachymedusa dacnicolor)","abstract":"Previous studies demonstrated that amphibians produce an abundance of bioactive peptides in their skin secretions. In this thesis a cDNA precursor encoding a novel peptide was cloned from the skin secretion of Mexican leaf frog, Pachymedusa dacnicolor. The deduced mature peptide was named QUB-1157 due to its molecular mass and consists of nine amino acid residues, pQEYTGWMDF-NH2. A series of biomolecular techniques were used in this thesis. Solid phase peptide synthesis was used to synthesise replicates of the novel peptide, and reversed-phase HPLC and MALDI-TOF MS was applied to purify peptide and confirm the mass. According to the peptide’s sequence, this novel peptide has been classified as a caerulein-like peptide. From the results of all experiments, this novel peptide did not show any significant contractions on the smooth muscle of rat gall bladder, ileum, urinary bladder, uterus and tail artery. Meanwhile, this novel peptide was not found to have any antimicrobial activity against C.albicans, E.coli and S.aureus. QUB-1157 also had no cytotoxicity on horse erythrocytes. However, QUB-1157 inhibited the proliferation of cancer cell line H-157 and U251MG. All these data indicate that it is probably necessary to research more about the structure-function relationship of this novel peptide.","abstract_html":"Previous studies demonstrated that amphibians produce an abundance of bioactive peptides in their skin secretions. In this thesis a cDNA precursor encoding a novel peptide was cloned from the skin secretion of Mexican leaf frog, Pachymedusa dacnicolor. The deduced mature peptide was named QUB-1157 due to its molecular mass and consists of nine amino acid residues, pQEYTGWMDF-NH2. A series of biomolecular techniques were used in this thesis. Solid phase peptide synthesis was used to synthesise replicates of the novel peptide, and reversed-phase HPLC and MALDI-TOF MS was applied to purify peptide and confirm the mass. According to the peptide’s sequence, this novel peptide has been classified as a caerulein-like peptide. From the results of all experiments, this novel peptide did not show any significant contractions on the smooth muscle of rat gall bladder, ileum, urinary bladder, uterus and tail artery. Meanwhile, this novel peptide was not found to have any antimicrobial activity against C.albicans, E.coli and S.aureus. QUB-1157 also had no cytotoxicity on horse erythrocytes. However, QUB-1157 inhibited the proliferation of cancer cell line H-157 and U251MG. All these data indicate that it is probably necessary to research more about the structure-function relationship of this novel peptide.","abstract_has_math":false,"creators":["Lyu, Chenyang"],"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","Ma, Chengbang"],"committee_chairs":[],"committee_members":[],"year":2018,"date_issued":"2018-8-6","date_published":"2018-8-6","updated_at":"2026-07-24T03:54:53Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:pure.qub.ac.uk/portal:studenttheses/c0d5d8a7-6ca3-471f-8e58-1b530a5092e2"],"render_values":[{"text":"oai:pure.qub.ac.uk/portal:studenttheses/c0d5d8a7-6ca3-471f-8e58-1b530a5092e2","href":null,"code":true}]}]},"links":{"outbound_url":"https://pure.qub.ac.uk/en/studentTheses/c0d5d8a7-6ca3-471f-8e58-1b530a5092e2","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","Ma, Chengbang"]},{"key":"dc:creator","label":"Author","values":["Lyu, Chenyang"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2018-8-6"]},{"key":"dc:date.issued","label":"Date","values":["2018-8-6"]},{"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/c0d5d8a7-6ca3-471f-8e58-1b530a5092e2"]},{"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":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights.embargodate","label":"Dc Rights Embargodate","values":["2023-09-30"]},{"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/c0d5d8a7-6ca3-471f-8e58-1b530a5092e2","https://pure.qub.ac.uk/en/studentTheses/c0d5d8a7-6ca3-471f-8e58-1b530a5092e2"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://pure.qub.ac.uk/files/157094709/Chenyang_Lyu_thesis.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Previous studies demonstrated that amphibians produce an abundance of bioactive peptides in their skin secretions. 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However, QUB-1157 inhibited the proliferation of cancer cell line H-157 and U251MG. All these data indicate that it is probably necessary to research more about the structure-function relationship of this novel peptide."]},{"key":"dc:title","label":"Title","values":["QUB-1157: a bioactive peptide from the skin secretion of the Mexican leaf frog (Pachymedusa dacnicolor)"]}]}],"canonical_facts":{"dc:contributor.advisor":["Zhou, Mei","Wang, Lei","Ma, Chengbang"],"dc:creator":["Lyu, Chenyang"],"dc:date":["2018-8-6"],"dc:date.issued":["2018-8-6"],"dc:description.abstract":["Previous studies demonstrated that amphibians produce an abundance of bioactive peptides in their skin secretions. In this thesis a cDNA precursor encoding a novel peptide was cloned from the skin secretion of Mexican leaf frog, Pachymedusa dacnicolor. The deduced mature peptide was named QUB-1157 due to its molecular mass and consists of nine amino acid residues, pQEYTGWMDF-NH2. 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