Antimicrobial activity of a novel moricin-like peptide from the Chinese oak silkworm against Vibrio pathogens in sea cucumbers

Abstract

Antimicrobial peptides (AMPs) from natural sources represent promising candidates for novel antimicrobial agents instead of antibiotics in aquaculture. Moricin, a family of AMPs from Lepidoptera, has shown bactericidal activity against both gram-positive and gram-negative bacteria. However, it remains uncertain whether these peptides possess antimicrobial activity against Vibrio pathogens affecting various aquatic animals, including sea cucumbers. In this study, we investigated five moricin-like peptides (MLPs) from Antheraea pernyi (Anpe) and identified Anpe-MLP1 as a new member of the moricin family through bioinformatics analysis. Anpe-MLP1 was heterologously expressed using the AnpeNPV bacmid system and purified from A. pernyi pupae. Our findings revealed that recombinant Anpe-MLP1 (rAnpe-MLP1) exhibited antimicrobial activity against gram-positive Staphylococcus aureus (S. aureus ATCC 6538 P), gram-negative Escherichia coli (E. coli ATCC 25922) and three Vibrio species. Moreover, both in vitro and in vivo assays showed that rAnpe-MLP1 effectively inhibited wild-type Vibrio fluvialis infections in the sea cucumber (Apostichopus japonicus). These results suggest that Anpe-MLP1 holds great potential as a novel anti-infective agent and provide valuable insights for its future application in aquaculture.

Keywords

• Antimicrobial peptides
• Vibrio pathogens
• AnpeNPV bacmid system
• Sea cucumber
• Aquaculture