Characterization of ammonium transporters in the dinoflagellate Alexandrium catenella (Group I).

Ammonium transporter AlcAMT with K450 residue enables ammonium uptake in Alexandrium catenella, a key factor in nitrogen utilization for toxin production.

• Why it matters: Understanding ammonium transport mechanisms in A. catenella is vital because nitrogen availability influences its growth and toxin synthesis, impacting shellfish safety and marine ecosystems.
• What they did: Researchers cloned multiple AMT cDNAs from A. catenella, expressed three variants in ammonium-deficient yeast, and identified K450 as essential for ammonium transport activity through mutation analysis.
• The result: The identification of AlcAMT with K450 advances knowledge of nitrogen uptake in dinoflagellates, providing insights that could inform strategies to mitigate harmful algal blooms and shellfish poisoning.