Examining hydrogen peroxide-containing organelles in seaweeds

Area of Science:

• Marine Biology
• Biochemistry
• Animal Nutrition

Background:

• Seaweeds, especially *Asparagopsis taxiformis*, are sources of bromomethanes.
• Bromomethanes are effective methane emission inhibitors in ruminants.
• Methane mitigation requires understanding seaweed biochemistry, particularly hydrogen peroxide (H₂O₂) production.

Purpose of the Study:

• To develop a staining assay for detecting H₂O₂ in diverse seaweed species.
• To investigate the role of H₂O₂ in bromoform synthesis within *Asparagopsis taxiformis*.
• To identify seaweed species with high bromoform content for potential use as feed supplements.

Main Methods:

• Development of a 3,3'-diaminobenzidine (DAB) staining assay.
• Application of the assay to red, brown, and green seaweeds, including pigmented varieties.
• Microscopic examination of seaweed tissues to locate H₂O₂-rich structures.

Main Results:

• The DAB assay successfully identified H₂O₂ in various seaweed types.
• A specialized organelle, previously termed "gland cell," in *Asparagopsis taxiformis* was confirmed as H₂O₂-rich.
• This organelle is crucial for bromoform synthesis and sequestration.

Conclusions:

• The developed DAB staining assay is an effective tool for surveying seaweed H₂O₂ content.
• The study elucidates the mechanism of bromoform production in *Asparagopsis taxiformis*.
• This research facilitates the discovery of novel seaweed resources for methane reduction in livestock.