Primary productivity maintenance through chlorophyll a changes in Elodea potamogeton during an annual cycle

Measurements of the photosynthetic rate (oxygen exchange) and concentration of chlorophyll a (Chl a) were conducted, during an annual light cycle, in Elodea potamogeton (Bert.) Espinosa, a submerged limnic plant with vegetative growth, found in Peru, Bolivia and Chile. In temperate Chile (Peñaflor), this plant grows abundantly in a lotic system whose waters have constant physical and chemical conditions and non-limiting nutrients during the year. The results showed that E. potamogeton is able to maintain, with a two-fold variation, a similar photosynthetic rate (P) all year round, with a mean and S.E. of 21.4 ± 0.6 mg O2 per g dry weight h-1. In contrast, the Chl a concentrations increased during winter, to between three and seven times of those observed at the end of spring. Plants exposed to similar irradiance variations showed an inverse relationship between their concentrations of Chl a and the total solar daily radiation (I) available 3 days prior to their collection. The light r

Perfil de toxinas de prorocentrum lima (Dinophyceae) aislado desde la costa de Magallanes, sur de Chile

1 póster presentado en el XXXII Congreso Ciencias del Mar, Punta Arenas, Chile, 22-26 de octubre de 2012El dinoflagelado bentónico Prorocentrum lima produce toxinas lipofílicas, que pueden ocasionar intoxicaciones diarreicas (VDM) en humanos consumidores de mariscos. En sedimentos recolectados en Cabo San Isidro, Estrecho de Magallanes, durante el invierno de 2010, se logró cuantificar una abundancia de 1002 quistes tecados de Prorocentrum lima cm-3 de sedimento, la mayor concentración respecto a otros sitios de recolecta. Se aislaron 27−87 quistes tecados directamente desde los sedimentos mientras otras 60 células vegetativas fueron aisladas luego de promover la actividad y división de los quistes en condiciones de 15 ºC y 12:12 horas luz–oscuridad. Las células fueron puestas independientemente en tubos Eppendorf, así como también, 100 μL aproximados de sedimento húmedo. Luego de congelados los tubos, la extracción de la toxina se realizó con 500 μL de metanol 100%, se mezcló, filtró por 0.45 μm, trasvasijando a un vial. El extracto fue secado bajo nitrógeno gas a 40 ºC y conservado a 4 ºC hasta su análisis. La presencia de la toxina dinofisistoxina 1 (DTX-1) en las muestras fue confirmada en modo negativo, por su ión padre [M-H]- m/z 817.5 y iones hijos m/z 563.4 y 255.2, mediante cromatografía líquida acoplada a un espectrómetro de masas. Previo a la inyección, los extractos fueron resuspendidos en 150 μL de metanol. El contenido de DTX-1 en las muestras fue cuantificado en base al ion padre. Las células vegetativas presentaron un mayor contenido de DTX-1 por célula, en comparación a las células de resistencia.Financiamiento: Manejo y Monitoreo de las mareas rojas en la regiones de Los Lagos, Aysén y Magallanes, IV etapa, 2010Peer reviewe

First report of the production of spirolides by Alexandrium peruvianum (Dinophyceae) from the Mediterranean Sea

Póster.-- 12th International Conference on Harmful Algae, Copenhagen, Denmark, 4-8 September 2006Four strains of Alexandrium peruvianum obtained from resting cysts in the western Mediterranean in 2002 and 2004 were analyzed for the presence of toxins. No PSP toxins were detected by LC-FD after postcolumn derivatization. Nevertheless, spirolides were detected by LC-MS in the four strains. The major components were 13-desmethyl spirolide C (m/z 692,5) with 90% of the total toxin content, followed by spirolide B (m/z 694,5) (6%) and small quantities of spirolide D (m/z 708,5) (2,7%) and 13-desmethyl spirolide D (m/z 694,5) (2%). Also traces of spirolide C (m/z 706,5) were found. This is the first report of the production of spirolides by this species. Given the great morphological similarity between A. peruvianum and A. ostenfeldii, in which the main difference is the shape of the sulcal anterior plate, triangular in A. peruvianum and rectangular with a left extension in A. ostenfeldii, the presence of these peculiar toxins in both species could be an indication of a possible synonymyN

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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Interannual variability in mesoscale distribution of Dinophysis acuminata and D. acuta in Northwestern Patagonian fjords

Dinophysis acuminata and D. acuta, which produce diarrheogenic toxins and pectenotoxins in southern Chile, display site-specific differences in interannual variability (2006 - 2018) in Reloncaví, Pitipalena and Puyuhuapi fjords (41 - 46 °S), Chilean Patagonia. Linear Models show decreasing trends in rainfall and river discharge. Latitudinal decreasing gradients in SST temperature and vertical salinity gradients were observed. A brackish water layer (FW salinity 103 cells L‒1) densities every season. Dinophysis acuminata, associated with toxin profiles in shellfish that include only pectenotoxins, bloomed everywhere with a poleward increasing gradient. Absence of the FW layer provides a possible index of risk for D. acuta blooms. An apparent poleward shift of D. acuta populations, responsible for DSP outbreaks in Reloncaví in the 1970s, and the recent EU deregulation of pectenotoxins will have a positive impact on the mussel industry in Los Lagos Region. Changes to ongoing monitoring protocols to improve risk assessment capabilities are suggested.This work was funded by ANID-FONDECYT 11170682 from the National Agency of Research and Development (ANID), Chile. Ángela M. Baldrich was funded by a Ph.D. fellowship from the Universidad de Los Lagos. Carlos Molinet was partially funded by INCAR (FONDAP, grant N°15110027). Beatriz Reguera was funded by the EU-Interreg Atlantic Area project PRIMROSE (EAPA_182/2016).Peer reviewe

Distribución espacial de Dinophysis spp. y detección de toxinas DSP en el agua mediante resinas Diaion (verano 2006, región de Los Lagos, Chile).

En Chile, la ocurrencia de episodios tóxicos diarreogénicos causados por dinoflagelados ha sido señalada en reiteradas oportunidades desde 1970 a la fecha con una mayor frecuencia de eventos en la zona sur-austral. Dinophysis acuta, D. acuminata, D. rotundata y D. caudata son las especies que se encuentran durante primavera y verano. Estos taxones han sido citados como productores de toxinas diarreicas en Europa a excepción de D. rotundata. Sin embargo, en nuestro país aún se desconoce la mayor parte de los perfiles y contenido de toxinas de las poblaciones que se encuentran presentes en nuestras costas. Debido a que las toxinas diarreicas son parcialmente liberadas al agua por las microalgas, ha sido posible realizar un seguimiento in situ de éstas en la columna de agua en varias partes del mundo mediante el uso de bolsitas conteniendo resinas sintéticas. Durante este estudio, se desplegaron bolsitas con resinas en diez estaciones ubicadas en la costa este de la isla de Chiloé, entre diciembre de 2005 y febrero de 2006. Los resultados mostraron que las toxinas predominantes en la columna de agua fueron PTX2 y DTX1 en ocho y tres de las estaciones, respectivamente, de un total de diez. El método fue suficientemente sensible para ser utilizado en la descripción de perfiles de toxinas lipofílicas. Sin embargo, para establecer una asociación entre las toxinas encontradas y la presencia de dinoflagelados nocivos en el agua, se requiere realizar un seguimiento de ambas variables durante un período estacional en el que suelen ocurrir las floraciones de algas nocivasIn Chile, the occurrence of diarrhoegenic toxic episodes caused by dinoflagellates has been indicated in repeated opportunities from 1970 to date with a greater events frequency in the south-austral zone of the country. Dinophysis acuta, D. acuminata, D. rotundata and D. caudata are the dinoflagellates present during spring and summer. These species have been reported to produce diarrhoegenic toxins in Europe with exception D. rotundata. Nevertheless it is not known with certainty the profiles and toxin content of the majority of the populations present in our coasts is unknown. Because diarrhoegenic toxins are partially released into water bodies has been possible to track them in situ in several parts of the world through the use of bags containing synthetic resins. During this study, synthetic resins contained into bags were suspended en the water column in 10 stations located in the East coast of Chiloé Island between December 2005 and February 2006. The results showed that the predominant toxins in the water column were PTX2 and DTX1 in eight and three of the stations, respectively. The method is sufficiently sensible to be used in the description of lipophilic toxin profiles and to associate them with the producing dinoflagellates of these toxins that are present in the water. Nevertheless, to establish an association between the toxins found and the harmful dinoflagellates present in the water, are required to track both variables during a seasonal period when usually the harmful algae blooms happen.Publicado

Characterisation of okadaic acid related toxins by liquid chromatography coupled with mass spectrometry

In the Diarrhetic Shellfish Poisoning (DSP) phenomena, the parent toxins, namely okadaic acid (OA) and/or dinophysistoxin-2 (DTX2), are predominantly found esterified. Therefore, a toxicity assessment of a sample can only be performed after an alkaline hydrolysis step in order to recover the parent molecules in their free form. The presence of several OA diol esters has already been confirmed in Prorocentrum lima and Prorocentrum belizeanum cultures. This paper reports on the analysis of OA diol esters using liquid chromatography coupled with mass spectrometry (LC–MS/MS), and establishes a method for their detection and identification based upon their retention times (RT) and the fragmentation patterns of their mass spectra.Versión del editor2,924

Alexandrium catenella cyst accumulation by passive and active dispersal agents: Implications for the potential spreading risk in Chilean Patagonian fjords

The dinoflagellate Alexandrium catenella is responsible for paralytic shellfish poisoning and negative socioeconomic impacts on the fishing industry and aquaculture. In Chilean Patagonia, the reasons underlying the significant increase in the geographical extension (from south to north) of A. catenella blooms during the last five decades are not well understood. To assess the potential spreading risk of A. catenella during an intense austral summer bloom, we conducted an in situ experiment in a "hotspot" of this dinoflagellate in southern Chile. The objective was to assess the accumulation of A. catenella resting cysts in passive (fishing nets) and active (mussels) dispersal agents during the phase of bloom decline. Large numbers of resting cysts were detected in fishing nets (maximum of 5334 cysts net−1 per month) at 5 m depth and in mussels (maximum of 16 cysts g−1 of digestive gland) near Vergara Island. The potential of these vectors to serve as inoculum sources and the implications of our findings for A. catenella population dynamics are discussed

Seasonal variability of lipophilic toxins during a Dinophysis acuta bloom in Western Iberia: Differences between picked cells and plankton concentrates.

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