| Résumé | Domoic acid (DA) was of no special scientific interest until a series of case studies revealed its role as the major marine neurotoxin causing amnesic shellfish poisoning (ASP). The analysis, toxicology, synthesis and degradation of the highly polar amino acid DA and its kainoid congeners are discussed in this chapter. Although DA is structurally simple and ubiquitous in contaminated food samples, it was not simple to prove that it was the causative agent of ASP in humans and of DA poisoning in carnivorous birds and mammals. Furthermore, its detection and the prevention of ASP requires regular monitoring of seafood using rapid and accurate analyses. The main producers of DA are certain seasonally blooming diatoms of the genus Pseudo-nitzschia, major components of coastal phytoplankton. Here, details are provided of the species most likely to be involved in food-poisoning episodes, together with a brief account of the molecular mechanisms that underlie DA toxicity, which cause symptoms of acute and chronic neurotoxicity. DA may attain critically toxic levels within two major food chains involving benthic filter-feeders (e.g., mussels) or planktivorous fish (e.g., anchovies). Preventive measures must be complemented by risk assessments of seasonal toxigenic blooms, especially in nutrient-enriched coastal areas. The major chemical and biotic factors that influence diatom bloom formation and toxigenicity are outlined. Genomics of DA production allow the development of novel molecular tools to better understand DA biosynthesis at the gene level, and the evolutionary significance of DA as a metabolite with primary and secondary characteristics. |
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