An outbreak of food poisoning in Canada during autumn 1987 was traced to cultured blue mussels (Mytilus edulis) from the Cardigan Bay region of eastern Prince Edward Island (P.E.I.). The toxin, identified as domoic acid, had not previously been found in any shellfish and this outbreak represents the first known occurrence of human poisoning by this neurotoxin. A plankton bloom at the time of the outbreak consisted almost entirely of the pennate diatom, Nitzschia pungens f. multiseries, and a positive correlation was found between the number of N. pungens cells and the concentration of domoic acid in the plankton. Nitzschia pungens f. multiseries isolated from Cardigan Bay produced domoic acid in culture at levels (1 to 20 pg∙cell−1) comparable with values estimated for N. pungens in the plankton samples. Isolates of several Cardigan Bay phytoplankton, including the closely related species Nitzschia seriata, failed to produce domoic acid. Other Nitzschia spp. and two Amphora coffeaeformis isolates also failed to produce domoic acid. We conclude that N. pungens was the major source of the domoic acid in toxic mussels in eastern P.E.I. The recurrence, in November 1988, of a monospecific bloom of N. pungens and the presence of domoic acid in plankton and mussels reinforced this conclusion.

Two polar lipid-soluble macrocycles 1 and 2, containing a spiro-linked tricyclic ether ring system and an unusual seven-membered spiro-linked cyclic iminium moiety, have been isolated from the digestive glands of mussels (Mytilus edulis) and scallops (Placopecten magellanicus).During chemical investigations of polar bioactive molecules from microalgae and shellfish,' we isolated from the digestive glands of both mussels (Mytilus edulis) and scallops (Placopecten magellanicus), a family of novel macrocycles which we have named spirolides A-D. Here we report the structural elucidation of the two major components, spirolides B and D.Spirolide B 1 and D 2 (Fig. 1) were purified from methanolic extracts of frozen digestive glands of shellfish collected from sites along the eastern shore of Nova Scotia.? High resolution LSIMS determined the molecular formulae for 1 and 2 to be C42H63N07 (MH+ 694.4651, 6 4.5) and C ~~H G ~N O ~

Three additional marine toxins, spirolides A (1), C (3), and 13-desmethyl-C (7), were isolated from contaminated scallops and phytoplankton collections obtained from a Nova Scotian aquaculture site, as well as from batch cultures of the dinoflagellate Alexandrium ostenfeldii obtained as a single-cell isolate from these phytoplankton assemblages. The structures of these new spirolide derivatives, characterized by mass spectrometry and NMR, indicate a close relationship with spirolides B (2) and D (4) isolated previously from contaminated shellfish in the same area. All of these compounds display "fast-acting" toxicity in the traditional bioassay used for monitoring shellfish, and this is related to the presence of a cyclic imine function in all these compounds. Those spirolides containing a vicinal dimethyl group in the seven-membered ring are resistant to oxalic acid hydrolysis, whereas those that do not are readily hydrolyzed. These observations suggest that the extra methyl group on the seven-membered imine ring of 3, 4, and 7 appears to block the process of imine hydrolysis perhaps by stereochemical interference.

. 67,481 (1989).The causative agent of toxicity in cultured mussels from a localized area of eastern Prince Edward Island has been identified as domoic acid, a neuroexcitatory amino acid. The toxin was isolated by a number of different bioassay-directed separation techniques including high-performance liquid chromatography, high-voltage paper electrophoresis, and ion-exchange chromatography, and characterized by a number of spectroscopic techniques including ultraviolet, infrared, mass spectrometry, and nuclear magnetic resonance. The isolation and purification methods are described in detail and some new analytical data for domoic acid are reported. On a identifie l'agent qui est la cause de la toxicit6 des moules d7Clevage provenant d'une zone localisCe de la portion est de l'ile du prince Edouard; il s'agit de l'acide domoi'que, un acide amink neuro-excitant. On a is016 la toxine en faisant appel L un certain nombre de techniques de skparation basCes sur des essais biologiques parmi lesquelles on peut citer la chromatographie liquide B haute performance, 1'Clectrophorkse sur papier B voltage ClevC ainsi que la chromatographie d'Cchange ionique; on l'a caractCrisCe par un certain nombre de techniques spectroscopiques dont I'ultraviolette, l'infrarouge, la spectromCtrie de masse et la rtsonance magnCtique nuclkaire. On dCcrit en detail les mCthodes d'isolement et de purification et on prksente des donnCes analytiques nouvelles concernant I'acide domoi'que.Mots cle's : toxine des coquillages, acide domoi'que, neurotoxine, analyse baste sur des essais biologiques.[Traduit par la revue]

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