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Title: Functional genomic studies on the skin secretions of frogs from southern China
Author: Ma, Jie
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2014
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The bioactive peptides are the one of the most important components of skin secretions. They are classified into two major groups: antimicrobial peptides and pharmacological peptides that include anticancer peptides, neuropeptides, and vasoactive peptides. Tachykinins, bradykinins and bombesins from amphibian skin secretions belong to both neuropeptide and vasoactive peptide groupings and some of their homologues have been identified from mammals. For this reason, they interact with specific receptors in mammals causing pharmacological effects. This thesis was concerned with functional genomic studies on the skin secretions of four different frog species from southern China. Four bioactive peptides are described from these frog skin secretions. G-21-C-HG and Ranakinestatin-PPF were initially identified via a "shotgun" cloning approach which identified their respective precursor-encoding cDNAs. The predicted structures of pep tides were confirmed by RP-HPLC, MALDI-TOF mass spectrometry and LCQ-Fleet electrospray ion-trap mass spectrometry. Finally, synthetic replicates of both peptides were evaluated for their bioactivities. G-21-C-HG, from Hylarana guentheri skin secretion was found to be a broad-spectrum antimicrobial peptide. It also had anticancer activity against human H23 and LNCaP cancer cells. Ranakinestatin-PPF from the skin secretion of the Fukien goldstriped pond frog, Pelophylax plancyi fukienensi, represented a prototype of a novel class of bradykinin B2 receptor antagonist peptide. Due to their pharmacological effects on rat smooth muscle preparations, TK-OL and QUB 1940 were defined as myotropic peptides and were from the skin of Odorrana livida and Amolops wuyiensis, respectively. All of the pep tides described had conserved structures within their biological cores. TK-OL, a novel tachykinin peptide, contracted the smooth muscle ofrat urinary bladder. QUB 1940, a novel bombesin-like peptide, not only contracted the smooth muscle of rat urinary bladder, but also increased the contractile frequency of rat uterus.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available