Florecimientos algales nocivos producidos por Pyrodinium bahamense en Oaxaca, México (2009-2010) / Harmful algal blooms produced by Pyrodinium bahamense in Oaxaca, Mexico (2009-2010)

Objetivo. Monitorear el dinoflagelado Pyrodinium bahamense y sus toxinas en ostión de roca Striostrea prismatica en Santiago Astata y en Puerto Escondido, Oaxaca, de septiembre de 2009 a junio de 2010. Material y métodos. Se analizó mensualmente la abundancia de Pyrodinium bahamense mediante el método de Sedgewick-Rafter y la concentración de toxinas paralizantes y perfil tóxico en tejido blando del molusco en muestras compuestas de cada zona por el método de cromatografía líquida de alta resolución. Resultados. Se encontró alta abundancia de Pyrodinium bahamense en Santiago Astata en diciembre, febrero, abril y junio, y en Puerto Escondido en abril y junio. Los niveles de toxinas paralizantes fueron superiores al límite permisible para consumo humano en Santiago Astata en noviembre, diciembre, enero, febrero y junio; en la zona de Puerto Escondido, en diciembre y junio. Conclusiones. Estos niveles de toxinas representaron riesgo para la salud pública en la zona de estudio.

Objective. Pyrodinium bahamense monitoring in water and their toxins in rock oyster Striostrea prismatica in Santiago Astata and Puerto Escondido Oaxaca was performed from September 2009 to July 2010. Materials and methods. Pyrodinium bahamense abundance in water, and concentration and toxic profile of paralytic shellfish toxins were analyzed monthly in soft tissue of mollusk in composite samples in high performance liquid chromatography. Results. High abundance of Pyrodinium bahamense was found in Santiago Astata on December, February, April and June; and in Puerto Escondido on April and June. The concentrations of the paralyzing toxin that exceeded the regulatory limit for human consumption of mollusks (800 µg STX eq. kg-1) were presented in Santiago Astata on November, December, January, February and June; and in Puerto Escondido on December and June. Conclusions. For several months there was risk to public health due to the presence of paralytic shellfish toxins above the regulatory limit in oysters from the study area.

Bloom of Gymnodinium catenatum in Bahía Santiago and Bahía Manzanillo, Colima, Mexico

Gymnodinium bloom events are of concern, since they produce toxins, which have unfavorable consequences to marine ecosystems, human health and the economy. This report describes the physico-chemical conditions that were present during the algal bloom event on May 2010 in Bahía Manzanillo and Bahía Santiago, Colima, Mexico. For this, seawater nutrient analysis, phytoplankton counts, identification, and toxicity tests were undertaken. Nutrients in seawater were determined using colorimetric techniques, the higher concentrations (8.88μM DIN, 0.78μM PO4 and 24.34μM SiO2) were related with upwelling waters that promoted the algal bloom that began after registering the year lowest sea-surface temperature, favoring the rapid growth of G. catenatum (up to 1.02 x10(7)cells/L). Phytoplankton counting was carried out using sedimentation chambers and cells enumerated on appropriated area. The bloom persisted in the bays for approximately two weeks and was associated with toxicity (determined with HPLC) in local oysters (1525.8μg STXeq/100g), and in phytoplankton (10.9pg STXeq/cells) samples. Strong variations in cell toxicity (1.4 to 10.9pg STXeq/cells), most likely reflected the availability of inorganic nutrients. The toxin profile of the phytoplankton samples consisted of 11 toxins and resembled those recorded for several strains of G. catenatum isolated from other coastal areas of Mexico.

La proliferación de Gymnodinium son motivo de preocupación, debido a que en algunas circunstancias producen toxinas, que tienen consecuencias desfavorables para los ecosistemas marinos, la salud humana y la economía. Este trabajo describe las condiciones fisicoquímicas presentes durante una proliferación algal detectado en mayo de 2010 en la Bahía de Santiago y Bahía Manzanillo (Colima, México). La proliferación algal inició poco tiempo después de registrarse las temperaturas oceánicas superficiales más bajas del año, las cuales permitieron un aumento de las concentraciones de nutrientes (8.88μM DIN, 0.78μM PO4 and 24.34μM SiO2) que favorecieron el desarrollo de G. catenatum (hasta 1.02 x10(7)cel/L). Esta proliferación se detectó en las bahías durante dos semanas y fue relacionada con toxicidad en ostiones de la localidad (1525.8μg STXeq/100g) y en muestras de fitoplancton (10.9pg STXeq/cel). Fuertes variaciones en la toxicidad de G. catenatum (1.4 a 10.9pg STXeq/cel) pudieron reflejar la disponibilidad de nutrientes inorgánicos. El perfil de toxinas de las muestras del fitoplancton consistieron en 11 toxinas semejantes a las de varias cepas de G. catenatum aisladas de otras áreas de las costas de México.

Phylogenetic analyses of Prorocentrum spp. and Alexandrium spp. isolated from northern coast of Vietnam based on 18S rDNA sequence.

Some species of marine dinoflagellates belonging to genera Alexandrium and Prorocentrum have been responsible for paralytic shellfish poisoning (PSP) and diarrheic shellfish poisoning (DSP), respectively Morphological and molecular studies of 4 species including Alexandrium sp. 5, Alexandrium sp. 16, Prorocentrum sp. 1 and Prorocentrum sp. 3 that were collected in Northern coast of Vietnam were presented for the first time. By morphologic observations, we identifiedAlexandrium sp. 5 and Alexandrium sp. 16 as Alexandrium minutum, Alexandrium affine, respectively; Prorocentrum sp. 1 and Prorocentrum sp. 3 as Prorocentrum mexicanum. Sequence data from the partial 18S riboxomal RNA genes have been used to generate a phylogenetic framework with database of GenBank. The obtained results of phylogenetic analyses of species of Prorocentrum spp. and Alexandrium spp. based on 18S rDNA sequences are similar to morphological observations. Thus, molecular tool would be helpful for the identification of dinoflagellate species and further taxonomic studies in Vietnam.

Human intoxication with paralytic shellfish toxins: clinical parameters and toxin analysis in plasma and urine

This study reports the data recorded from four patients intoxicated with shellfish during the summer 2002, after consuming ribbed mussels (Aulacomya ater) with paralytic shellfish toxin contents of 8,066 n 61.37 mg/100 gr of tissue. Data associated with clinical variables and paralytic shellfish toxins analysis in plasma and urine of the intoxicated patients are shown. For this purpose, the evolution of respiratory frequency, arterial blood pressure and heart rate of the poisoned patients were followed and recorded. The clinical treatment to reach a clinically stable condition and return to normal physiological parameters was a combination of hydration with saline solution supplemented with Dobutamine (vasoactive drug), Furosemide (diuretic) and Ranitidine (inhibitor of acid secretion). The physiological condition of patients began to improve after four hours of clinical treatment, and a stable condition was reached between 12 to 24 hours. The HPLC-FLD analysis showed only the GTX3/GTX2 epimers in the blood and urine samples. Also, these epimers were the only paralytic shellfish toxins found in the shellfish extract sample.

Use of sodium transfer tissue biosensor (STTB) for monitoring of marine toxic organism.

A highly sensitive sodium (Na+) transfer tissue biosensor (STTB) was designed using a frog bladder membrane to measure paralytic shellfish poisons (PSP). The STTB consists, of a Na+ electrode covered by the membrane, which was then integrated into a flow-through system for continuous measurements. In the absence of Na+ channel blocker, active transfer of Na+ occurred from inside to outside across the frog membrane. When the STTB was used to measure the Na+ -dependent dissociation of PSP, it was able to detect PSB at a level contained in a single cell. However, 5 fg or higher (100 cells or more) is needed for accurate and reproducible measurements. The toxicity obtained by the STTB was significantly correlated (r = 0.9449) to that determined by the HPLC. Therefore, the simple method of the STTB can be used not only to detect a low level PSP in toxic plankton populations, but also to monitor poisons in shellfish.

Decoloración en proliferaciones de microalgas como parámetro bioindicador en la Bahía de Mazatlán, México / Discoloration of microalgal blooms as a bioindicating parameter of Bahia de Mazatlan, Mexico

Hace 25 años la UNAM desarrolló un programa de observación y muestreo de mareas rojas en la Bahía de Mazatlán (1979-2003), con el propósito de conocer su evolución a través del tiempo. Se apoyó en observaciones diarias de las decoloraciones (manchas) y los resultados indican cinco tendencias: I) Años sin días de manchas, los cuales están asociados al fenómeno de El Niño; II) Años de días con manchas súbitas; III) Años con un número similar de días de manchas; IV) Años con una disminución progresiva de los días de manchas; V) Años con un aumento gradual de manchas. El promedio anual es de 25.3 días de decoloraciones. En el año 2000 hubo 96 días de decoloraciones y representa el más alto en los 25 años de registros. En marzo es donde existen mas frecuentemente las manchas de mareas rojas (174 días) incluyendo las tóxicas. Estas tendencias nos indican un comportamiento continuo de la máxima concentración de las microalgas y por lo tanto desempeñan un papel muy importante para conocer el deterioro ambiental que sufren las zonas costeras por aumento de microalgas nocivas y tóxicas

In order to verify whether harmful algal blooms increased since 1979, a long-term project for the study of harmful algal blooms in Mazatlán Bay began 25 years ago (1979-2003). Observations were done daily and results indicate five trend types: I) years without discoloration related to El Niño events; II) years with days of sudden occurrence of discoloration, related to the release of accumulated energy after El Niño events; III) years with similar number of discoloration events (days); IV) years with a progressive decrease of the occurrence (days) of discoloration events; V) years with gradual increase of discoloration events. The annual mean average of discoloration is of 25.3 days. Ninety-six discoloration events were recorded during year 2000, and represent the highest number of events in the last 25 years. Discoloration events are more common in March (174 days), harmful and toxic blooms included. This indicates continuity in the occurrence of the highest content of microalgae, and therefore, it is concluded that they play an important role for a better understanding of the environmental deterioration undergone by the coastal zone due to an increase of harmful and toxic microalgae blooms

Ficoflórula do açude de Apipucos (Recife-PE) / Ficoflorula of the Apipucos reservoir (Recife-PE)

O Açude de Apipucos está localizado na área urbana do Recife, há anos vem sofrendo efeito da eutrofizaçäo artificial, pois recebe freqëntemente despejos, principalmente de natureza orgânica, tais como, esgotos e lixo domiciliares. A Ficoflórula está distribuída em 4 (quatro) Divisöes, 12 (doze) Ordens, 48 (quarenta e oito) gêneros, 36 (trinta e seis) espécies, 10 (dez) variedades e 3 (três) formas. A ordem Chlorococcales foi a melhor representada, tanto em termos qualitativos e quantitativos. Cerca de 95% das espécies identificadas säo características de águas eutróficas