2026-10-10T01:09:13Z https://api.figshare.com/v2/oai

oai:figshare.com:article/32631822 2026-10-01T17:16:29Z portal_1172 item_type_8 month_year_10_2026

Identification and activity assessment of a bioactive peptide QUB-1368 from the skin secretion of the American bullfrog (Rana catesbeiana) Huishu Lin (16826691) PUREID: 250509114 Antimicrobial peptides bioactivity evaluation antimicrobial activity haemolytic activity temporin peptides Polypeptides in amphibian skin secretions have various bioactive functions, especially the positively-charged, alpha-helical and amphipathic polypeptides. In this study, a novel antimicrobial peptide isolated from the skin secretions of Rana catesbeiana was named QUB-1368. After establishing the cDNA library, the biosynthetic precursor was obtained through molecular cloning, and then the mature peptide QUB-1368 was deduced from the precursor. QUB-1368 was then obtained in quantity by solid-phase peptide synthesis for biological activity experiments. The purified synthetic peptide QUB-1368 was identified by reversed-phase high-performance liquid chromatography (HPLC) and Matrix-Assisted Laser Desorption/ Ionization Time of Flight Mass Spectrometry (MALDI-TOF). In this study, QUB-1368 showed a broad-spectrum antibacterial activity to Gram-negative bacteria (64 µM against E. coli ATCC CRM 8739), Gram-positive bacteria (32 µM against S. aureus ATCC CRM 6538) and yeast (64 µM against C. albicans ATCC CRM 10231). In addition, in the concentration range of 102-10-3 µM, QUB-1368 has no inhibitory effect on the human lung cancer cell line (H838). In the haemolysis assay, QUB-1368 showed haemolytic activity at a concentration of 256 µM, when QUB-1368 showed antibacterial activity, the concentration did not reach to produce hemolysis. In summary, QUB-1368 may have good clinical research value.<br><br><i>Thesis embargoed until 31 December 2026</i>. 2026-10-01T17:16:29Z Text Thesis 10.17034/32631822.v1 https://figshare.com/articles/thesis/Identification_and_activity_assessment_of_a_bioactive_peptide_QUB-1368_from_the_skin_secretion_of_the_American_bullfrog_Rana_catesbeiana_/32631822 All Rights Reserved Open Access after 2026-12-31