Ferredoxin: A novel antimicrobial peptide derived from the black scraper (Thamnaconus modestus)

Area of Science:

• Marine biology
• Biochemistry
• Immunology

Background:

• Ferredoxin (FDX) is a conserved iron-sulfur protein crucial for electron transport in biological redox reactions.
• The specific functions of FDX in marine fish, particularly in immune responses, are not well understood.

Purpose of the Study:

• To identify and characterize two ferredoxin proteins (FDX1 and FDX2) from the black scraper fish (Thamnaconus modestus).
• To investigate the expression patterns of these FDX genes in response to bacterial infection.
• To explore the antimicrobial properties of synthesized peptides derived from FDX sequences.

Main Methods:

• Identification and genetic structure analysis of TmFDX1 and TmFDmFDX2 genes.
• Quantitative analysis of TmFDX mRNA expression in various tissues of healthy and infected fish.
• Synthesis of antimicrobial peptides (pFDX1, pFDX2) based on FDX sequences.
• Evaluation of peptide bactericidal activity, biofilm inhibition, and gDNA binding.

Main Results:

• TmFDX1 and TmFDX2 mRNAs were primarily detected in peripheral blood leukocytes.
• Following Vibrio anguillarum infection, TmFDX1 showed significant upregulation in most tested tissues except the brain.
• TmFDX2 expression increased in several tissues but remained unchanged in the brain and gills.
• Synthesized peptides (pFDX1, pFDX2) demonstrated bactericidal effects, inhibited biofilm formation, and bound to gDNA.

Conclusions:

• The study elucidates the genetic structure and immune-related expression profiles of TmFDX1 and TmFDX2 in black scraper fish.
• The findings suggest that TmFDXs play a role in the fish immune system, particularly in response to bacterial pathogens.
• Derived peptides from TmFDXs show promise as natural antimicrobial agents for potential therapeutic applications in aquaculture.