A novel antimicrobial peptide Spamprin4-23 from Scylla paramamosain exhibiting potent antimicrobial activity and protective effects against Vibrio alginolyticus.

چکیده اصلی

Vibrio species are ubiquitous in aquatic environments and represent significant pathogens in marine aquaculture, with Vibrio alginolyticus being a primary threat to farmed aquatic animals. The limited availability of therapeutic drugs in aquaculture, compounded by widespread antibiotic resistance, necessitates the development of new antibacterial strategies. In this study, a previously uncharacterized functional gene, designated as Spamprin, was identified in Scylla paramamosain. Its transcripts exhibited tissue-specific distribution and were markedly upregulated following LPS stimulation. Through bioinformatics analysis and prediction using antimicrobial peptide databases, a truncated peptide, Spamprin4-23 derived from Spamprin was screened. The peptide demonstrated potent antimicrobial activity against a wide range of microorganisms in vitro. Mechanistically, Spamprin4-23 significantly increased bacterial membrane permeability and induced morphological changes in target microorganisms. Importantly, it exhibited no cytotoxic effects against crab hemocytes or mammalian HEK293T cells. Although Spamprin4-23 showed no direct bactericidal activity against V. alginolyticus in vitro, it reduced bacterial burden in host tissues and conferred significant protection, leading to improved survival of V. alginolyticus-challenged mud crabs. This effect was most likely associated with the immunomodulatory activity of the peptide, as evidenced by the modulation of immune-related gene expression. Collectively, these findings suggest that Spamprin4-23 may serve as a promising immunomodulatory agent for disease control in aquaculture, offering a viable alternative to conventional antibiotic-based strategies.

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