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.

. 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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Fullerenes Cm and C70, generated by combustion, have been shown previously to be produced in controlled laminar flames accompanied by other compounds having fullerene-like characteristics. Analysis of these additional compounds by high-performance liquid chromatography, coupled on-line with mass spectrometry has identified them as isomers of the Cm and C70 fullerenes. The newly observed isomers have characteristic UV spectra and are thermally unstable, undergoing conversion to the more stable fullerenes with a half-life of about 1 h in boiling toluene (111 "C). Isomers of Cm and C70 fullerenes previously have been studied theoretically, but not observed experimentally. The flame-generated material also contains CmO and C700 compounds, as well as C76 and higher carbon clusters.The structure of the remarkably stable carbon cluster C,,, first discovered' in vapour from laser irradiation of graphite and subsequently produced in macroscopic quantities by resistive heating of graphite under an inert is now widely accepted as a truncated icosahedron ('soccer ball fullerene'), while the homologue C,, is assigned an ellipsoidal cage structure ('rugby ball')., In this paper the terms 'buckminsterfullerene' and 'fullerene' are taken to refer to these highly symmetrical closed-cage carbon clusters. Recently' it was shown that Cm and C,, fullerenes, isolated from samples of condensible compounds and soot collected from controlled combustion of benzene in pre-mixed laminar flames, were spectroscopically indistinguishable from fullerenes prepared from graphite. Analysis of the flame samples by high-performance liquid chromatography (HPLC) with ultraviolet spectroscopic detection (UVD) also revealed the presence of several additional components with fullerene-like characteristics.8 Attempts to characterize these HPLC fractions, via isolation and mass spectrometric analysis using direct insertion probe and conventional electron ionization (El) and chemical ionization (CI) methods, failed to give any meaningful results.Efficient methods for the analysis of polycyclic aromatic compounds (PACs) of high molecular weight, by HPLC or supercritical fluid chromatography (SFC) coupled directly to mass spectrometry (LC/MS or SFC/MS), have been developed recently.'-" These methods employ either a moving-belt interface with flash heating of the analyte as it enters the EI source,'.1o or a heated pneumatic nebulizer coupled to an atmospheric-pressure chemical ionization (APCI) source in which electron transfer to benzene molecular cations is arranged to be the dominant ionization mechanism." In the present work, the flame soot samt NRCC No. 33014.Author to whom correspondence should be addressed. ples were analysed by these complementary LC/MS techniques, as well as by HPLC interfaced on-line to a diode array detector for UV spectroscopy. EXPERIMENTAL Maferials.The extracts of flame-generated soots and condensates were identical to those described previously.' A sample of soot produced by resistive heating of and one of a purified extract of ...