In June 2007 the Chemical Ecology of Marine Protists group performed a scientific cruise on the North Sea. One of the aims of this expedition was to detect azaspiracids (AZAs), a group of marine toxins with unknown origin, and to isolate the AZA-producing organism. Azaspiracids are a group of lipophilic algal toxins associated with the diarrhetic shellfish poisoning (DSP) syndrome. The first azaspiracid poisoning (AZP) event was known after eight people in the Netherlands had become ill in November 1995 after consumption of mussels from the Irish west coast. Symptoms of the affected persons were nausea, vomiting, severe diarrhea and stomach cramps. These symptoms were typical for DSP. However, the only DSP toxins present in the mussels were okadaic acid and dinophysistoxin-2 at very low concentrations, which could not explain the observed intoxications [1]. Three years later, in 1998 Satakes group isolated and structurally elucidated azaspirazid-1 (AZA-1) as the causative compound in shellfish [2]. Consequently other human intoxications from the consumption of mussels in Ireland, France and Italy were unambiguously attributed to AZP. During the following years other structural variants of AZA-1 were detected and isolated from shellfish [3-5] and to date 11 AZAs are known, of which only AZA-1, AZA-2 and AZA-3 have been found in plankton samples [6]. Additionally it turned out that AZP was not restricted to Ireland alone, but AZA-contaminated mussels were also found on the English east cost as well as on the Norwegian west coast [7], but no AZAs were found further north in the White Sea, Northern Russia [8]. During the North Sea cruise (AZA-1) was measured in size fractionated plankton net tows (20 µm mesh size) by a highly sensitive triple quadrupole-linear ion trap LC-MS/MS. Highest amounts of AZA-1 were present in the southern Skagerrak in the 20-3 µm size fraction. From that fraction, a large number of crude cultures were established by use of serial dilution and, after 8 weeks of growth, screened for the presence of AZAs. From one crude culture containing AZA, a small dinoflagellate was subsequently isolated by micro capillary and brought into pure culture. The isolated strain produces AZA-1, AZA-2 and a so far unknown isomer of AZA-2.References:[1] McMahon, T., Harmful Algae News, 1996, 14, 2.[2] Satake, M., Journal of the American Chemical Society, 1998, 120, 9967-9968.[3] Ofuji, K., Natural Toxins, 1999, 7, 99-102.[4] Ofuji, K., Bioscience, Biotechnology, and Biochemistry, 2001, 65, 740-742.[5] James, K.J., Toxicon, 2003, 41, 277-283.[6] Furey, A., Environmental Science and Technology, 2003, 37, 3078-3084.[7] James, K.J., Toxicon, 2002, 40, 909-915.[8] Vershinin, A., Harmful Algae, 2006, 5, 558-564.