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Marine pelagic diazotrophic cyanobacteria of the genus Trichodesmium (Oscillatoriales) are widespread throughout the tropics and subtropics, and are particularly common in the waters of New Caledonia. Blooms of Trichodesmium are suspected to be a potential source of toxins in the ciguatera food chain and were previously reported to contain several types of paralyzing toxins. The toxicity of water-soluble extracts of Trichodesmium spp. were analyzed by mouse bioassay and Neuroblastoma assay and their toxic compounds characterized using liquid chromatography coupled with tandem mass spectrometry techniques. Here, we report the first identification of palytoxin and one of its derivatives, 42-hydroxy-palytoxin, in field samples of Trichodesmium collected in the New Caledonian lagoon. The possible role played by Trichodesmium blooms in the development of clupeotoxism, this human intoxication following the ingestion of plankton-eating fish and classically associated with Ostreopsis blooms, is also discussed.

Marine pelagic diazotrophic cyanobacteria of the genus Trichodesmium (Oscillatoriales) are widespread throughout the tropics and subtropics, and are particularly common in the waters of New Caledonia. Blooms of Trichodesmium are suspected to be a potential source of toxins in the ciguatera food chain and were previously reported to contain several types of paralyzing toxins. The toxicity of water-soluble extracts of Trichodesmium spp. were analyzed by mouse bioassay and Neuroblastoma assay and their toxic compounds characterized using liquid chromatography coupled with tandem mass spectrometry techniques. Here, we report the first identification of palytoxin and one of its derivatives, 42-hydroxy-palytoxin, in field samples of Trichodesmium collected in the New Caledonian lagoon. The possible role played by Trichodesmium blooms in the development of clupeotoxism, this human intoxication following the ingestion of plankton-eating fish and classically associated with Ostreopsis blooms, is also discussed. [ABSTRACT FROM AUTHOR]

Abstract: Palytoxin (PlTX) and palytoxin-like (PlTX-like) compounds in seafood have been raising scientific concern in the last years. The constant increase in record numbers of the causative dinoflagellates of the genus Ostreopsis together with the large spatial expansion of this genus has led to intensification of research towards optimization of methods for determination of PlTX presence and toxicity. In this context, identification of seafood species which could possibly contain PlTXs constitutes an important issue for public health protection. In the present paper, worldwide occurrence of PlTX-like compounds in seafood is reviewed, while potential future strategies are discussed. PlTX has been reported to be present in several species of fish, crustaceans, molluscs and echinoderms. In one occasion, PlTX has been identified in freshwater puffer fish whereas all other records of PlTXs refer to marine species and have been recorded in latitudes approximately between 43°N and 15°S. PlTX determination in seafood has relied on different methodologies (mainly LC-MS, mouse bioassay and hemolysis neutralization assay) that have evolved over time. Future recommendations include systematic screening of PlTX in those species and areas where PlTX has already been recorded implementing updated methodologies. [Copyright &y& Elsevier]

Benthic dinoflagellates of the genusOstreopsisSchmidt are common in tropical and subtropical water, and some species produce toxins potentially involved in human intoxication events. A benthic bloom ofOstreopsis mascarenensisQuod was observed near Rodrigues Island during a survey of benthic dinoflagellates in the southwestern Indian Ocean. The morphology ofO. mascarenensiswas studied by LM and SEM. Preliminary screening of a crude extract of anO.mascarenensisbloom revealed neurotoxicity in mice similar to that induced by palytoxin. After partition of the crude extract, the highest toxicity was retained in the butanol-soluble fraction, which retained hemolytic activity suggestive of palytoxin analogues. Two new toxins, mascarenotoxin-A and -B, were resolved from this fraction by HPLC coupled to a diode array detector. The closed mass spectrum profile and fragmentation pattern obtained by advanced nano–electrospray ionization quadrupole time-of-flight mass spectrometry between purified toxins and a reference palytoxin confirmed the mascarenotoxins as palytoxin analogues. These results were confirmed by tandem mass spectrometry with the identification of specific fragment ionm/z327. An on-line liquid chromatography protocol coupled to tandem mass spectrometry was developed for detection of these palytoxin analogues. The present study describes the first purification, chemical, and toxicological characterization of new palytoxin analogues isolated from a benthic bloom ofO. mascarenensis. These results suggest thatO. mascarenensis, which is largely distributed in the southwestern Indian Ocean, could be a source of palytoxin poisoning in this tropical area. [ABSTRACT FROM AUTHOR]