American Society of Hirudotherapy

The molecular characterization, expression analysis and antimicrobial activity of theromacin from Asian polychaeta (Perinereis linea)

Basic science / preclinical published in Dev Comp Immunol (2020)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Preclinical (animal)Salivary PharmacologyGenomics & ProteomicsJoo MS et al. · Developmental and comparative immunology, 2020

Abstract

Antimicrobial peptides (AMPs) are molecular factors in innate immunity and are believed to play a key role in invertebrate host defence. We identified theromacin (TM) from an Asian polychaeta, Perinereis linea, using de novo RNA-seq analysis. TM, a typical AMP of invertebrates, is a cysteine-rich AMP with five disulfide bonds consisting of ten cysteine residues. In gene expression analysis, TM genes were constantly upregulated after lipopolysaccharide (LPS) stimulation. In contrast, after peptidoglycan (PGN) stimulation, it was upregulated initially and downregulated after 12 h. We synthesized a peptide based on the macin AMP in the TM amino acid sequence. The synthetic peptide showed antibacterial activity against some Gram-positive and Gram-negative bacteria. Therefore, the AMPs of P. linea might have broad roles in host defence and exhibit different degrees of activity.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal ArticleResearch Support, Non-U.S. Gov't
Indexed MeSH termsAnimalsAntimicrobial Cationic PeptidesBacterial InfectionsCloning, MolecularGene Expression ProfilingGram-Negative BacteriaGram-Positive BacteriaInflammationLipopolysaccharidesPeptidesPhylogenyPolychaeta

Summary

Identification of theromacin (TM), a cysteine-rich AMP family member originally described in leeches, from the Asian polychaete Perinereis linea. Recombinant peptide shows broad-spectrum antibacterial activity and LPS-responsive expression.

Why This Matters for Hirudotherapy

This study identified and characterized theromacin (TM), a cysteine-rich antimicrobial peptide (AMP) with five disulfide bonds, from the Asian polychaeta Perinereis linea via de novo RNA-seq. TM gene expression was upregulated after LPS stimulation (sustained) and PGN stimulation (initially upregulated, downregulated after 12 h); a synthetic macin-domain peptide showed antibacterial activity against some Gram-positive and Gram-negative bacteria. For ASH's domain, the relevance is indirect at best: while AMPs are a common theme in invertebrate innate immunity and could conceptually parallel leech antimicrobial peptides, this study involves a polychaete worm, not a leech, and no leech species or leech-derived molecules are mentioned. The note should plainly state that no leeches are involved and there is no direct relevance to hirudotherapy or the leech secretome.

Citation

The molecular characterization, expression analysis and antimicrobial activity of theromacin from Asian polychaeta (Perinereis linea).

Joo MS et al. · Developmental and comparative immunology, 2020

DOI

Added to ASH library: May 27, 2026 · Site last updated: June 18, 2026

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