Reconocimiento de dos variedades taxonómicas de Pyrodinium bahamense (Gonyaulacales, Dinophyceae): var. bahamense y var. compressum

Antecedentes y Objetivos: Pyrodinium es un género monotípico con dos variedades, var. bahamense en el Atlántico, no tóxica, y var. compressum en el Indo-Pacífico y tóxica. Hallazgos recientes de toxicidad por envenenamiento paralitico por mariscos (PSP), en poblaciones de P. bahamense var. bahamense, debilitaron el interés por aceptarlas como independientes, e incluso investigar la posibilidad de cripticismo. En los pocos estudios que han incorporado evidencia molecular en el tratamiento de las variedades, su independencia taxonómica sigue siendo negada, a pesar de la evidente y consistente separación genética presentada en todos los análisis. Por lo tanto, el objetivo de este estudio fue reconocer, desde la evidencia genética, la independencia taxonómica de las dos variedades de Pyrodinium: P. bahamense var. compressum y var. bahamense. Métodos: A partir de tres marcadores moleculares (Lcf, LSU, SSU) de secuencias disponibles en el Genbank, se construyeron redes de parsimonia estadística y un análisis filogenético concatenado. Resultados clave: En todos los análisis, se obtuvo de manera consistente una estructura genética para P. bahamense var. bahamense y otra para P. bahamense var. compressum. Además, la correspondencia de haplotipos y ribotipos resultantes fue siempre la misma, tanto en redes como en la filogenia; es decir, las muestras del Océano Pacífico siempre se colocaron en un grupo distinto al de las secuencias del Océano Atlántico. Conclusiones: La evidencia proporcionada en este estudio demostró que existe un aislamiento reproductivo entre ambas variedades, e incluso la posible presencia de una tercera variedad aún no descrita, por lo cual proponemos la validez e independencia taxonómica de P. bahamense var. compressum y P. bahamense var. bahamense.

Biochemical Mapping of Pyrodinium bahamense Unveils Molecular Underpinnings behind Organismal Processes

Proteins, lipids, and carbohydrates from the harmful algal bloom (HAB)-causing organism Pyrodinium bahamense were characterized to obtain insights into the biochemical processes in this environmentally relevant dinoflagellate. Shotgun proteomics using label-free quantitation followed by proteome mapping using the P. bahamense transcriptome and translated protein databases of Marinovum algicola, Alexandrium sp., Cylindrospermopsis raciborskii, and Symbiodinium kawagutii for annotation enabled the characterization of the proteins in P. bahamense. The highest number of annotated hits were obtained from M. algicola and highlighted the contribution of microorganisms associated with P. bahamense. Proteins involved in dimethylsulfoniopropionate (DMSP) degradation such as propionyl CoA synthethase and acryloyl-CoA reductase were identified, suggesting the DMSP cleavage pathway as the preferred route in this dinoflagellate. Most of the annotated proteins were involved in amino acid biosynthesis and carbohydrate degradation and metabolism, indicating the active roles of these molecules in the vegetative stage of P. bahamense. This characterization provides baseline information on the cellular machinery and the molecular basis of the ecophysiology of P. bahamense.

High-Resolution Spatiotemporal Dynamics of Harmful Algae in the Indian River Lagoon (Florida)—A Case Study of Aureoumbra lagunensis, Pyrodinium bahamense, and Pseudo-nitzschia

The Indian River Lagoon (IRL), located on the east coast of Florida, is a complex estuarine ecosystem that is negatively affected by recurring harmful algal blooms (HABs) from distinct taxonomic/functional groups. Enhanced monitoring was established to facilitate rapid quantification of three recurrent bloom taxa, Aureoumbra lagunensis, Pyrodinium bahamense, and Pseudo-nitzschia spp., and included corroborating techniques to improve the identification of small-celled nanoplankton (<10 μm in diameter). Identification and enumeration of these target taxa were conducted during 2015–2020 using a combination of light microscopy and species-specific approaches, specifically immunofluorescence flow cytometry as well as a newly developed qPCR assay for A. lagunensis presented here for the first time. An annual bloom index (ABI) was established for each taxon based on occurrence and abundance data. Blooms of A. lagunensis (>2 × 108 cells L–1) were observed in all 6 years sampled and across multiple seasons. In contrast, abundance of P. bahamense, largely driven by the annual temperature cycle that moderates life cycle transitions and growth, displayed a strong seasonal pattern with blooms (105–107 cells L–1) generally developing in early summer and subsiding in autumn. However, P. bahamense bloom development was delayed and abundance was significantly lower in years and locations with sustained A. lagunensis blooms. Pseudo-nitzschia spp. were broadly distributed with sporadic bloom concentrations (reaching 107 cells L–1), but with minimal concentrations of the toxin domoic acid detected (<0.02 μg L–1). In summer 2020, multiple monitoring tools characterized a novel nano-cyanobacterium bloom (reaching 109 cells L–1) that coincided with a decline in A. lagunensis and persisted into autumn. Statistical and time-series analyses of this spatiotemporally intensive dataset highlight prominent patterns in variability for some taxa, but also identify challenges of characterizing mechanisms underlying more episodic yet persistent events. Nevertheless, the intersect of temperature and salinity as environmental proxies proved to be informative in delineating niche partitioning, not only in the case of taxa with long-standing data sets but also for seemingly unprecedented blooms of novel nanoplanktonic taxa.

sxtA4+ and sxtA4- Genotypes Occur Together within Natural Pyrodinium bahamense Sub-Populations from the Western Atlantic

Saxitoxin (STX) is a secondary metabolite and potent neurotoxin produced by several genera of harmful algal bloom (HAB) marine dinoflagellates. The basis for variability in STX production within natural bloom populations is undefined as both toxic and non-toxic strains (of the same species) have been isolated from the same geographic locations. Pyrodinium bahamense is a STX-producing bioluminescent dinoflagellate that blooms along the east coast of Florida as well as the bioluminescent bays in Puerto Rico (PR), though no toxicity reports exist for PR populations. The core genes in the dinoflagellate STX biosynthetic pathway have been identified, and the sxtA4 gene is essential for toxin production. Using sxtA4 as a molecular proxy for the genetic capacity of STX production, we examined sxtA4+ and sxtA4- genotype frequency at the single cell level in P. bahamense populations from different locations in the Indian River Lagoon (IRL), FL, and Mosquito Bay (MB), a bioluminescent bay in PR. Multiplex PCR was performed on individual cells with Pyrodinium-specific primers targeting the 18S rRNA gene and sxtA4. The results reveal that within discrete natural populations of P. bahamense, both sxtA4+ and sxtA4- genotypes occur, and the sxtA4+ genotype dominates. In the IRL, the frequency of the sxtA4+ genotype ranged from ca. 80–100%. In MB, sxtA4+ genotype frequency ranged from ca 40–66%. To assess the extent of sxtA4 variation within individual cells, sxtA4 amplicons from single cells representative of the different sampling sites were cloned and sequenced. Overall, two variants were consistently obtained, one of which is likely a pseudogene based on alignment with cDNA sequences. These are the first data demonstrating the existence of both genotypes in natural P. bahamense sub-populations, as well as sxtA4 presence in P. bahamense from PR. These results provide insights on underlying genetic factors influencing the potential for toxin variability among natural sub-populations of HAB species and highlight the need to study the genetic diversity within HAB sub-populations at a fine level in order to identify the molecular mechanisms driving HAB evolution.

Distribusi dan Kelimpahan Kista Pyrodinium bahamense di Perairan Rawan Marak Alga Berbahaya di Indonesia

<strong>Distribution and abundance of <em>Pyrodinium bahamense</em> cyst in the harmful algal blooms risk waters in Indonesia. </strong><em>Pyrodinium bahamense</em>as Harmful Algal Blooms (HABs) is one of the rising environmental problems in the coastal areas of Southeast Asia, particularly in Indonesia. Cyst bank formed after the blooms of <em>P. bahamense</em> is a potential source for the future blooming events. Therefore, an effort to describe the distribution and abundance of <em>P. bahamense</em> cyst banks in Indonesian coastal waters is necessary as a part of the mitigation strategy against the negative impacts of those toxic dinoflagellate blooms. This study was done as a desk study, which included a literature study, reanalysed of previous research data, and reanalysed of preserved samples or stored raw samples. Data and samples used in this study were collected and analysed from part of past researches in Lampung Bay, Jakarta Bay, Cirebon coastal waters, and Ambon Bay. This study also included an analysis to determine the <em>P. Bahamense </em>HABs risk level in the studied areas based on the cyst density and distribution data. Results showed a low density of <em>P. bahamense </em>cyst in Lampung Bay and Jakarta Bay, with cyst density &lt;50 cysts.g^-1 wet sediment. In contrast, the bottom sediments of Ambon Bay and Cirebon coastal waters contained high cyst density, which reached &gt;1,000 cysts.g^-1 wet sediment. Based on those data, the <em>P. Bahamense </em>HABs risk in Jakarta Bay and Lampung Bay would be generally much lower compared to Ambon Bay and Cirebon waters. The existence of cyst banks in those coastal waters may indicate a possibility of future blooms of <em>P. bahamense</em>.

Florecimiento algal nocivo por Pyrodinium bahamense en diciembre 2018 en la Costa del Pacifico de Guatemala

Los florecimientos algales nocivos (FAN) son eventos naturales que ocurren cuando una o más especies de microalgas proliferan en concentraciones que pueden causar daño a los organismos acuáticos y a seres humanos quienes los consuman. En las últimas décadas, se ha registrado a nivel mundial un aumento de eventos de mortalidad alarmante de organismos acuáticos e intoxicaciones en seres humanos causadas por toxinas producidas por microalgas. En Guatemala existe escasa información sobre eventos FAN, no obstante, en diciembre de 2018 ocurrió un FAN en la costa Pacífico de Guatemala. La Comisión Nacional para la Vigilancia y el Control de la Marea Roja Tóxica recolectó muestras biológicas e identificó la presencia de 3,000 cel/L del dinoflagelado Pyrodinium bahamense. El bioensayo en ratón de las muestras, indica concentraciones de saxitoxina de 8,236 UR/100 g y 6,559 UR/100 g, para los días 20 y 27 de diciembre, respectivamente. Estas concentraciones no han sido reportadas previamente en Guatemala, y pueden ser potencialmente tóxicas para la salud pública. Se recomienda mantener un monitoreo de FAN para prevenir impactos negativos en la salud pública y ambiental.

Co-ocurrence of two toxic dinoflagellates in Acapulco Bay, Guerrero, Mexico: an opportunity to quantify their biology and ecology

Background and Aims: Harmful Algal Blooms (HAB) commonly occur in the Mexican Pacific, being important HABs of Gymnodinium catenatum (Gc) and of Pyrodinium bahamense var. compressum (Pbc) for being saxitoxin-producing dinoflagellates that cause paralytic shellfish poisoning. The latter is a taxon that sporadically occurs in the tropical Mexican Pacific. This study describes the behavior of both taxa throughout the annual cycle and analyzes their morphology, abundance, distribution, and their bloom dynamics, in relation to environmental and climatological parameters.Methods: Phytoplankton collections were made ten times from October 2009 to January 2011 within Acapulco Bay and its surroundings, together with measurements of physicochemical parameters. Climatic data were obtained from Acapulco weather station. Abundance of phytoplankton was evaluated with the Utermöhl method. Statistical analyses were carried out to investigate the relationship of Gc and Pbc abundances with environmental and climatic parameters. Key results: Gc was present throughout the year 2010 in low densities and in November 2010 it reached a maximum of 189×103 cells l-1, associated with several species of diatoms and dinoflagellates, including Pbc. Gc bloom coincided with decrease in ammonium and decrease in water temperature with respect to the average. Pyrodinium bahamense morphometry from Acapulco corresponds to var. compressum. Pbc formed an intense HAB in July 2010 (reaching a maximum abundance of 773×103 cells l-1), causing significant toxicity and had an upturn in November. Conclusions: Pbc HABs in Acapulco require the occurrence of a previous HAB in the central Pacific or Gulf of Tehuantepec, Mexico, horizontal transportation of their cysts, as well as high water temperature conditions, abundant rainfall that increased the concentration of phosphates, which is propitiated in the periods of transition El Niñoˮ-La Niñaˮ events. Gc HABs in Acapulco are related to “La Niña” events, with an abrupt change in water temperature and an increase in nitrogenous forms.Key words: ENSO, Gymnodinium catentum, HAB, Mexican tropical Pacific, morphometry, Pyrodinium bahamense var. compressum. Resumen:Antecedentes y Objetivos: Los florecimientos algales nocivos (FAN) ocurren comúnmente en el Pacífico mexicano, siendo importantes los de Gymnodinium catenatum (Gc) y Pyrodinium bahamense var. compressum (Pbc), dinoflagelados productores de saxitoxina que causan envenenamiento paralítico por mariscos. Pbc se presenta esporádicamente en el Pacifico tropical mexicano. El estudio describe el comportamiento de ambos taxa en un ciclo anual y analiza su morfología, abundancia, distribución y dinámica del FAN en relación con parámetros ambientales y climatológicos. Métodos: Se realizaron diez recolectas de fitoplancton (octubre 2009-enero 2011) en la Bahía de Acapulco y zona costera adyacente, y mediciones de parámetros fisicoquímicos. Los datos climáticos se obtuvieron de la estación meteorológica de Acapulco. La abundancia del fitoplancton se evaluó con el método de Utermöhl. Se realizaron análisis estadísticos para investigar la relación de las abundancias de Gc y Pbc con parámetros ambientales y climáticos. Resultados clave: Gc estuvo presente durante todo el año 2010 con densidades bajas; en noviembre de 2010 alcanzó un máximo de 189×103 células l-1, asociado con especies de diatomeas y dinoflagelados, incluyendo Pbc. El florecimiento de Gc coincidió con disminución de amonio y disminución de temperatura del agua con respecto al promedio. La morfometría de Pb de Acapulco correspondió con la var. compressum. Pbc formó un intenso FAN en julio de 2010 (abundancia máxima de 773×103 células l-1), causando una toxicidad significativa y tuvo un repunte en noviembre. Conclusiones: Los FAN de Pbc en Acapulco requieren un FAN previo en el Pacífico central o en el Golfo de Tehuantepec, transporte horizontal de sus quistes, alta temperatura del agua y abundante precipitación que aumente la concentración de fosfatos; condiciones que se propician en los períodos de transición”El Niño”-La Niña”. Los FAN de Gc en Acapulco están relacionados con eventos “La Niña”, siendo importantes el cambio abrupto de temperatura del agua y el aumento de formas nitrogenadas.Palabras clave: ENSO, FAN, Gymnodinium catentum, morfometría, Pacífico tropical mexicano, Pyrodinium bahamense var. compressum.

Florecimientos algales nocivos en las costas de Campeche, Golfo de México

El presente estudio describe el estado de conocimiento sobre florecimientos algales nocivos (FAN) en las aguas costeras del estado de Campeche, México. Se realizó una búsqueda bibliográfica de 1965 a 2014 consultando reportes oficiales, reuniones académicas y artículos especializados (aproximadamente 30). El análisis de la literatura mostró que ha habido un avance significativo en los reportes de FAN. La abundancia de las especies nocivas presentó valores altos (106 células l-1) durante la temporada de lluvias (junioseptiembre). Se registró la presencia de especies potencialmente nocivas: los dinoflagelados Karenia brevis, Pyrodinium bahamense var. bahamense, Prorocentrum mexicanum, P. minimum y la cianobacteria Cylindrospermopsis cuspis.