Azaspiracids (AZA), produced by the dinoflagellate Azadinium spinosum, are a group of harmful algal bloom toxins that are notable for contaminating seafood. Our interests have focused on determining AZA's mechanism of action. One possible mechanism is that it acts like an ionophore, a molecule that uncontrollably transports ions across the lipid bilayer. In parallel with AZA1, one of the many known AZA analogs, we have performed comparative assays against three known ionophores; gramicidin, monensin, and nigericin. We observed that all four toxins caused time- and concentration-dependent cytotoxicity towards Jurkat lymphocyte T cells. Effective concentrations that induced a half maximal response (EC50) ranged between 1.3-35.5nM for AZA1, 618-3550nM for gramicidin, 816-13100nM for monensin, and 66.5-2220nM for nigericin, when tested at 24h intervals over 72h. Ongoing studies are documenting the morphological effects of these toxins on lymphocyte T cells and future studies will assess the antibacterial properties of these toxins.

Comparative ionophoric studies of the marine algal toxin azaspiracid

243rd National Meeting (2012)

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