Environmental roles and biological activity of domoic acid: A review

Abstract

Domoic acid (DA) is classified as a potent neurotoxin, an excitatory amino acid naturally produced by several diatom species belonging to the genus Pseudo-nitzschia. The molecule is excitotoxic in the vertebrate central nervous system, myocardium and other organs that contain glutamate receptors. The biggest risk of DA exposure for humans comes from the consumption of DA-contaminated shellfish. Algal blooms, including diatom blooms, are an excellent source of biomass for filter-feeding marine organisms, which makes the knowledge of DA occurrence quite relevant. In recent years, DA exposure has become more widespread due to the higher prevalence of toxigenic Pseudo-nitzschia blooms and increased human consumption of seafood. There is therefore an urgent need to update frequently the latest information on DA. Symptoms of having consumed high doses of DA are known but there are still significant gaps in knowledge of the health effects of chronic exposure to low levels of DA as well as of effective methods for removing DA from shellfish tissues. Here we summarize current knowledge about DA: its structure and biological activity, degradation in seawater, ecological and physiological roles, new producers, and risks of human exposure to high and low concentrations of this toxin.