Ostreopsis siamensis

Dinofiagellates belonging to the genus Ostreopsis have been proposed as possible biogenetic origins of palytoxin (Usami et al. 1995 Taniyama et al. 2003). This theory is further supported because of the implication of Ostreopsis siamensis in a case of clupeotoxism where the causative agent was found to be palytoxin or one of its analogues (Onuma et al. 1999). 

Ostreopsis siamensis was first isolated by Schmidt in the Gulf of Siam, Thailand, in 1901 (Schmidt 1901). This dinoflagellate occurs in mat r tropical and subtropical areas of the world, mainly as epiphytic and less frequently as planktonic, and also in temperate areas during summertime. Until today, the presence of O. siamensis has been reported in the coastal waters of Japan (Yasumoto et al. 1987), New Zealand (Chang et al. 2000 Rhodes et al. 2000), Tasmania (Pearce et al. 2000), Spain, Italy (Vila et al. 2001 Penna et al. 2005), Greece (Aligizaki et al. 2005), and Tunisia (Turki 2005). 

Rhodes, L., Towers, N., Briggs, L., Munday, R., and Adamson, J. 2002. Uptake of palytoxin-like compounds by shellfish fed Ostreopsis siamensis (Dinophyceae). New Zealand Journal of Marine and Freshwater Research 36(3) 631-636. 

Ukena, T, Satake, M., Usami, M., Oshima, Y, Fujita, T, Kan, Y, and Yasumoto, T. 2001. Structure elucidation of ostreocin-D, a palytoxin analog isolated from the dinoflagellate Ostreopsis siamensis. Bioscience, Biotechnology and Biochemistry 65(ll) 2585-2588. 

In New Zealand s subtropical coastal waters Ostreopsis siamensis is frequently present as epiphytic on seaweeds and planktonic in some occasions as well (Chang et al. 2000 Rhodes et al. 2000). Since 1994, restrictions on the harvesting of oyster in Rangaunu Harbour, Northland,... 

Table 6.1. Evaluation of toxicity and toxin analyses conducted on Ostreopsis siamensis cells isolated from...

Rhodes, L., Adamson, X, Suzuki, T, Briggs, L., and Garthwaite, I. 2000. Toxic marine epiphytic dinofiagellates, Ostreopsis siamensis and Coolia monotis (Dinophyceae), in New Zealand. JVZJA/arFres/jwaferRes 34, 371-383. 

Another zoanthid-derived polyketide that is likely produced by a dinoflagellate is palytoxin (125), an extremely potent neurotoxin from Palythoa toxica and several other unrelated animals. The closely related ostreocins, for example, ostreocin D (126), have been reported from a free-living dinoflagellate Ostreopsis siamensis, indicating a similar source in the animal. ... 

Yasumotto, T. et al., Palytoxin analogs from the dinoflagellate Ostreopsis siamensis, J. Am. Chem. Soc.,... 

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