Evaluation of passive samplers as a monitoring tool for early warning of Dinophysis toxins in shellfish

From June 2006 to January 2007 passive samplers (solid phase adsorbing toxin tracking, SPATT) were tested as a monitoring tool with weekly monitoring of phytoplankton and toxin content (liquid chromatography–mass spectrometry, LC-MS) in picked cells of Dinophysis and plankton concentrates. Successive blooms of Dinophysis acuminata, D. acuta and D. caudata in 2006 caused a long mussel harvesting closure (4.5 months) in the Galician Rías (NW Spain) and a record (up to 9246 ng·g resin-week−1) accumulation of toxins in SPATT discs. Best fit of a toxin accumulation model was between toxin accumulation in SPATT and the product of cell densities by a constant value, for each species of Dinophysis, of toxin content (average) in picked cells. Detection of Dinophysis populations provided earlier warning of oncoming diarrhetic shellfish poisoning (DSP) outbreaks than the SPATT, which at times overestimated the expected toxin levels in shellfish because: (i) SPATT accumulated toxins did not include biotransformation and depuration loss terms and (ii) accumulation of toxins not available to mussels continued for weeks after Dinophysis cells were undetectable and mussels were toxin-free. SPATT may be a valuable environmental monitoring and research tool for toxin dynamics, in particular in areas with no aquaculture, but does not provide a practical gain for early warning of DSP outbreaks

Planktonic dinoflagellates which contain polyether toxins of the old ¿DSP Complex¿

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First detection of Pectenotoxin-11 and confirmation of OA-D8 diol-ester in Dinophysis acuta from European waters by LC-MS/MS

During November 2005, a dense bloom of Dinophysis spp. dominated (>97%) by Dinophysis acuta in the Galician Rías Baixas (NW Spain), provided a unique opportunity to describe the full toxin profile – including toxins that represent a low percentage and escape detection in analyses of single-cell isolates – in plankton concentrates rich in this species. Detection and identification of toxins were carried out by liquid chromatography coupled to mass spectrometry (LC–MS/MS), a method that is based on their retention times (RT) and the fragmentation patterns of their mass spectra. OA-D8 diol-ester and PTX11 were detected in co-occurrence with okadaic acid analogues (OA, DTX2) and PTX2 in plankton concentrates dominated by D. acuta. The presence of a PTX11-isomer, which was suggested to be PTX13 or a novel PTX11-isomer, released in the sea water, was also confirmed in samples obtained after deployment of passive samplers (SPATT) in situ at the time of the D. acuta bloom maximum. The amount of PTX11 per cell of D. acuta, estimated as PTX2 equivalents, ranged between not detected and 2.2 pg cell-1, and represented a maximum of 2.9% of the total toxin content. The variation in PTX11 content per cell of D. acuta, during a daily cycle, followed the same pattern than that of PTX2, with maxima at 21:00 and 03:00 h (dark hours), but the amounts per cell were one order of magnitude lower. This is the first report of PTX11, together with the confirmation of OA-D8 diol-ester in D. acuta populations from Europe.Publicado

Considerations on the toxigenic nature and prey sources of Phalacroma rotundatum

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¿Es Dinophysis rotundata una especie toxigénica?

X Reunión Ibérica sobre Fitoplancton Tóxico y Biotoxinas = X Reuniao Ibérica de Fitoplâncton Tóxico e Biotoxinas, Lisboa, 12-15 Maio 2009Dinophysis rotundata Claparède & Lachmann es un dinoflagelado planctónico, ampliamente distribuido en aguas frías y templadas, clasificado por algunos autores como Phalacroma rotundata por su carácter heterótrofo y la forma de su epiteca (visible en presentación lateral). Está siempre presente en las Rías Bajas gallegas en concentraciones bajas (< 103 cel L-1). Los primeros análisis cromatográficos realizados con células aisladas en los años 80 sugirieron que esta especie tenía un elevado contenido de DTX1. Datos recientes obtenidos mediante cromatografía líquida de alta resolución acoplada a espectrómetro de masas (HPLC-MS) han suscitado dudas sobre el contenido de toxinas de esta especie y a sospechar que datos aislados del pasado pudieran ser “falsos positivos” producidos por los métodos de derivatización empleados. En este trabajo se analizan células de D. rotundata aisladas mediante micromanipulación a lo largo de diferentes años,. Los resultados muestran que solamente 4 de las 11 muestras analizadas contienen trazas de toxinas lipofílicas. En dichas muestras había un alto porcentaje de otras especies fototróficas de Dinophysis productoras de las mismas toxinas. Observaciones al microscopio de epifluorescencia mostraron especímenes de D. rotundata con vacuolas digestivas con restos de ficoeritrina similares a los encontrados en su potencial presa, Tiarina fusas, presente en las mismas muestras. Nuestra hipótesis es que D. rotundata no produce toxinas lipofílicas de novo, sino que las adquiere a través de la ingestión de presas (ciliados) que se alimentan a su vez de otros Dinophysis productores de toxinasN

Is Dinophysis rotundata a toxigenic species?

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Growth, behaviour and cell toxin quota of Dinophysis acuta Ehrenberg during a daily cycle

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Extraction of microalgal toxins by large-scale pumping of seawater in Spain and Norway, and isolation of okadaic acid and dinophysistoxin-2.

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