[A fluorimetric microplate assay for detecting diarrheic shellfish poisoning toxins]

Area of Science:

• Marine Biology
• Toxicology
• Biochemistry

Background:

• Diarrheic Shellfish Poisoning (DSP) poses a significant public health risk.
• Okadaic acid (OA) is a primary toxin responsible for DSP.
• Accurate and sensitive detection methods for OA are crucial for seafood safety.

Purpose of the Study:

• To develop and validate a novel assay for detecting OA-induced cytotoxicity.
• The assay is based on the F-actin depolymerization mechanism.
• To establish a reliable method for monitoring OA in shellfish.

Main Methods:

• Utilized HL-7702 liver cells stained with Oregon Green-514 phalloidin to visualize F-actin.
• Measured F-actin depolymerization using a fluorimetric microplate reader after OA treatment.
• Compared assay results with Enzyme-Linked Immunosorbent Assay (ELISA) for validation.

Main Results:

• Okadaic acid induced F-actin depolymerization in a dose-dependent manner.
• A linear correlation was observed between OA concentration (2.5-40 nmol/L) and F-actin depolymerization (R² = 0.993).
• The assay demonstrated a detection limit of 2.01 µg/100g in shellfish extracts with 90-100% recovery, showing high consistency with other methods (R² = 0.830).

Conclusions:

• The F-actin fluorescence assay is a promising method for OA detection in shellfish.
• The assay offers advantages of convenience, speed, and high sensitivity.
• This method contributes to enhanced food safety by enabling reliable toxin monitoring.