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oai:figshare.com:article/32638212 2026-10-01T16:46:50Z portal_1172 item_type_8 month_year_10_2026

Identification and functional study of a bioactive peptide, QUB1333, from the skin secretion of Rana dybowskii Guannan Wu (448184) PUREID: 526186846 Antimicrobial peptides (AMPs) Rana dybowskii molecular cloning skin secretion bioactivity evaluation Rana dybowskii is a traditional medicinal animal in ancient China, whose skin is proven to be capable of wound healing, and modern biology has revealed an abundance of antimicrobial peptides (AMPs) in its skin secretion. In recent times, researchers have shed light on amphibian-derived AMPs as potential therapeutic agents against multidrug-resistant pathogens. Here we report a novel peptide cloned from the skin secretion of Rana dybowskii. The nucleotide sequence of the peptide precursor was determined through molecular cloning and identified through the utilisation of a kit containing a provided CDS primer and a degenerate primer. The degenerate primer was specifically designed to target a segment of signal peptide of complementary DNAs (cDNAs) that had been previously cloned from the skin of Rana dybowskii. This identification process involved the implementation of the rapid amplification of cDNA ends (RACE) method. Following the Sanger sequencing, the nucleotide sequences were translated into peptide precursors. Upon the result of BLASTP, a novel peptide was identified and produced by solid phase synthesis and an Fmoc strategy. The reverse-phase high-performance liquid chromatography (RP-HPLC) was employed for purification and the product was determined by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The peptide was given a name QUB1333 by its molecular weight. The antimicrobial effects were evaluated by the Minimum Inhibitory Concentration (MIC) assay on E. coli, S. aureus, and C. albicans. The antiproliferation effects were tested using MTT against adenocarcinoma cell line NCI-H838. The cytotoxicity was evaluated by haemolysis assay with horse erythrocytes. As a result, the peptide only exhibited slight inhibition activity against E. coli, S. aureus, and C. albicans at 512 micromolar. The antiproliferative effect on NCI-H838 cells was detected at 256 and 512 micromolar with 48 hours dosing. Meanwhile, no significant haemolysis effects were observed up to 512 micromolar. It is important to note that despite the lack of bioactivity observed in these specific assays, QUB1333 might still possess a distinct biotarget within other tissues, cells, or host organisms.<br><br><i>Thesis is embargoed until 31 December 2028.</i> 2026-10-01T16:46:50Z Text Thesis 10.17034/32638212.v1 https://figshare.com/articles/thesis/Identification_and_functional_study_of_a_bioactive_peptide_QUB1333_from_the_skin_secretion_of_Rana_dybowskii/32638212 All Rights Reserved Open Access after 2028-12-31