Nitzschia pungens

The term amnesic shellfish poison (ASP) has been coined for this new shellfish toxin. The causative organism of ASP was then identified to be the pennate diatom Nitzschia pungens Grunow f. multiseries Hasle, a bloom of which contaminated the cultured mussels in eastern Prince Edward Island in 1987. 

In 1987, the first confirmed case of a naturally occurring neurotoxic diatom bloom was reported in Prince Edward Island, Canada, later confirmed to be caused by the production of domoic acid from the pennate diatom Nitzschia pungens, now renamed Pseudo-nitzschia multiseries (Bates et ah, 1989 Subba Rao et ah, 1988). Since this first outbreak, many (but not aU) species of Pseudo-nitzschia have been confirmed to produce domoic acid (as well as some species of Amphora and now Nitzschia (Kotaki et ah, 2000) see Bates, 1998, 2000, for a summary). These potentially toxic species include P. multiseries, P. pseudodelicatissima, P. delicatissima, P. seratia, P. australis, P. pungens, and P.fraudulenta, although it is apparent that not aU species are toxic in aU locations, nor are individual strains toxic under aU conditions. 

Subba Rao, D., QuiUiatn, M., and Pocklington, R. (1988). Domoic acid—neurotoxic amino acid produced by the marine diatom Nitzschia pungens in culture. Can. J. Fish. Aquat. Sd. 45, 2076-2079. 

Bates, S.S., de Freitas, A.S.W., Milley, J.E., Pocklington, R., Quilliam, M.A., Smith, J.C. and Worms, J. (1991) Controls on domoic acid production by the diatom Nitzschia pungens f. multiseries in culture nutrients and irradiance. Canadian Journal of Fisheries and Aquatic Science, 48, 1136-1144. 

Given this backgroimd, it is easy to see how mussels suspended in a water column teeming with domoic acid rich Nitzschia pungens... 

Bates, S. S., et al. Pennate diatom Nitzschia pungens as the primary source of domoic acid, a toxin in shellfish from eastern Prince Edward Island, Canada. Can. J. Fish. Aquat. Set, 46, 1203-1215 (1989). 

Douglas, D. J., et al. Domoic acid production by axenic and non-axenic cultures of the pennate diatom Nitzschia pungens f. multi series, in Toxic Phytoplankton Blooms in the Sea (ed. by Smayda, T. J. and Shimizu, Y.) Elsevier Science Publishers B. V., Amsterdam, 1993, pp. 595-600. 

Domoic acid is a naturally occurring excitatory amino acid that was identified as the toxin responsible for an outbreak of amnesic shellfish poisoning that occurred in Canada in 1987 following consumption of contaminated blue mussels (Mytilus edulis) [1] as well as numerous other outbreaks worldwide. The parent compound is a tricarboxylic amino acid produced by certain marine organisms, the best characterized of which are the red alga Chondria armata and the planktonic diatom Nitzschia pungens, although other species are also known to produce domoic acid (for review, see Reference 2). 

Pseudo-nitzschia pungens, Eucampia zoodiacus, Cossinodis-cus excentricus, Paralia sulcata, and Lauderia annulata... 

The species Nitzschia pungens form a multiseries, at the origin of the mortal intoxications of 1987, was renamed Pseudo-nitzschia multiseries. An agonist is a substance that has the same mode of action as the control. When the action is the opposite, the substance is known as an antagonist. 

Bacillariolide I (R = a-H) Bacillariolide II (R = 3-H) Nitzschia pungens forma multiseries Wang et al., 1993... 

Douglas, D.J., Ramsey, U.P., Walter, J.A., and Wright, J.L.C. (1992) Biosynthesis of the nemotoxin domoic acid by the marine diatom Nitzschia pungens forma multiseries, determined wilh [ C]-labeIled... 

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