Monitoring toxic Ostreopsis cf. ovata in recreational waters using a qPCR assay.

Ostreopsis sp. is a toxic marine benthic dinoflagellate that causes high biomass blooms, posing a threat to human health, marine biota and aquaculture activities, and negatively impacting coastal seawater quality. Species-specific identification and enumeration is fundamental because it can allow the implementation of all the necessary preventive measures to properly manage Ostreopsis spp. bloom events in recreational waters and aquaculture farms. The aim of this study was to apply a rapid and sensitive qPCR method to quantify Ostreopsis cf. ovata abundance in environmental samples collected from Mediterranean coastal sites and to develop site-specific environmental standard curves. Similar PCR efficiencies of plasmid and environmental standard curves allowed us to estimate the LSU rDNA copy number per cell. Moreover, we assessed the effectiveness of mitochondrial COI and cob genes as alternative molecular markers to ribosomal genes in qPCR assays for Ostreopsis spp. quantification

Phytoplankton RNA/DNA and 18S rRNA/rDNA ratios in a coastal marine ecosystem

The RNA/DNA ratio is used as indicator of growth in various marine organisms and to assess physiological status at species or community level. To evaluate the utility of the RNA/DNA ratio as a proxy of phytoplankton primary production, the relationships between phytoplankton RNA/DNA, taxon-specific diatom and dinoflagellate 18S rRNA/rDNA ratios and autotrophic phytoplankton biomass were investigated as a first step. Significant correlations between all phytoplankton ratios and total phytoplankton, diatom and dinoflagellate biomass as chlorophyll a (chl a) and carbon content were found. Diatoms showed higher correlation than dinoflagellates (18S rRNA/rDNA vs. chl a, rs =0.74 and 0.64, P <0.001; 18S rRNA/rDNA vs. carbon, rs =0.66 and 0.53, P <0.001, respectively), because they represented the most abundant and frequent group within sampled assemblages. Further, phytoplankton biomass production is known to be linked to protein biosynthesis and significant relationships between RNA/DNA ratios and protein content of phytoplankton assemblage were found (rs =0.62 and 0.52, P <0.001 for diatom and dinoflagellates, respectively). As taxon-specific RNA/DNA ratios were correlated with biomass and protein content, our results can be regarded as the first step toward further studies on the applicability of RNA/DNA ratios as indicators of growth rate and primary production in phytoplankton assemblages

A model predicting the {PSP} toxic dinoflagellate Alexandrium minutum occurrence in the coastal waters of the {NW} Adriatic Sea

Increased anthropic pressure on the coastal zones of the Mediterranean Sea caused an enrichment in nutrients, promoting microalgal proliferation. Among those organisms, some species, such as the dinofagellate Alexandrium minutum, can produce neurotoxins. Toxic blooms can cause serious impacts to human health, marine environment and economic maritime activities at coastal sites. A mathematical model predicting the presence of A. minutumin coastal waters of the NW Adriatic Sea was developed using a Random Forest (RF), which is a Machine Learning technique, trained with molecular data of A. minutumoccurrence obtained by molecular PCR assay. The model is able to correctly predict more than 80% of the instances in the test data set. Our results showed that predictive models may play a useful role in the study of Harmful Algal Blooms (HAB)

Assessment of Sustainable Construction dictation module Interdisciplinary Master

El objetivo de este trabajo es presentar una evaluación sobre los resultados del dictado del módulo Construcción Sustentable en una maestría interdisciplinaria de la UBA. La propuesta didáctica parte de la necesidad de impartir conceptos sobre construcción sustentable a alumnos de posgrado formados en disciplinas no afines a la arquitectura y la construcción. Un aspecto importante es el desarrollo de un trabajo práctico, indispensable para la aprobación del módulo, que contemplara o bien se adaptara a las diferencias en la formación profesional de los alumnos, que en muchos casos provienen de otros países latinoamericanos. Luego de la experiencia llevada a cabo con distintas cohortes, se presentan los ajustes realizados en el programa del módulo y los resultados obtenidos en los trabajos realizados por los alumnos.The aim of this paper is to present the results of the Sustainable Construction module issued an interdisciplinary master of the University of Buenos Aires. The design of the didactic proposal was based in the need to teach sustainable building concepts to graduate students not trained in disciplines related to architecture and construction. Another aspect was to develop a practical work, necessary to approve the module, that contemplate and also could be adapted to the differences in the training of students, who often come from other Latin American countries. This article presents the results obtained after carried out different cohorts, considering the changes in the program module and the results of the work done by the students.Eje: Educación y formación en sustentabilidad (actas).Facultad de Arquitectura y Urbanism

Identificación de especies de Chattonella (Raphidophyceae) presentes en muestras de fitoplancton recogidas durante un monitoreo de larga duración en la Laguna de Santa Giusta (Cerdeña, Italia)

Chattonella species in a Mediterranean lagoon (Santa Giusta Lagoon, Sardinia, Italy) were identified by applying a molecular approach to fixed natural phytoplankton samples collected over the last two decades. Like the other raphidophytes, Chattonella cells are naked and lose their shape when fixed, making species identification difficult on the basis of their morphological characteristics. Employing species-specific primers (oBTG-005-F, oBTG-027-R, oBTG-028-R) for the amplification of the ITS-5.8S rDNA region, we established the occurrence of C. subsalsa in fixed natural phytoplankton samples collected in coincidence with fish death events. Additionally, we established the presence of the recently discovered C. cf. subsalsa Adriatic genotype by analysing cellular cultures obtained from the same lagoon in 2013. This is the second worldwide record of C. cf. subsalsa Adriatic genotype. Our results revealed that the species-specific primers oBTG-005-F and oBTG-028-R distinguished this new genotype only when present singularly. This study provides valuable data that increase knowledge of C. subsalsa genotypes and of the long-term occurrence of Chattonella blooms in a transitional ecosystem through the use of samples up to 20 years old.Se identificaron especies de Chattonella mediante la aplicación de técnicas moleculares en muestras naturales de fitoplancton. Las muestras fueron recogidas y fijadas durante las últimas dos décadas en una laguna litoral mediterránea (Laguna de Santa Giusta, Cerdeña, Italia). Al igual que otras rafidoficeas, las células de Chattonella no poseen teca y, por lo tanto, pierden su forma cuando se fijan lo que dificulta la identificación basada en características morfológicas. Con el uso de cebadores específicos a nivel de especie (OBTG-005-F, OBTG-027-R, OBTG-028-R) diseñados para la amplificación de la región ITS- 5.8S rDNA, se detectó la presencia de C. subsalsa en las muestras recogidas en periodos coincidentes con eventos de muerte de peces. A través del análisis de los cultivos celulares obtenidos de la misma laguna en el año 2013, se identificó la presencia, por segunda vez a nivel mundial, del recientemente descubierto genotipo Adriático de C. cf. subsalsa. Los resultados revelaron que los cebadores oBTG-005-F y oBTG-028-R amplifican este nuevo genotipo sólo cuando está presente individualmente. En este estudio se presentan datos relevantes para el conocimiento de los genotipos de C. subsalsa y sobre la presencia recurrente de proliferaciones de especies de Chatonella en un ecosistema de transición a través de la utilización de muestras recogidas durante los últimos veinte años y analizadas hoy en día

Identification of Chattonella (Raphidophyceae) species in long-term phytoplankton samples from Santa Giusta Lagoon, Italy

none7noChattonella species in a Mediterranean lagoon (Santa Giusta Lagoon, Sardinia, Italy) were identified by applying a molecular approach to fixed natural phytoplankton samples collected over the last two decades. Like the other raphidophytes, Chattonella cells are naked and lose their shape when fixed, making species identification difficult on the basis of their morphological characteristics. Employing species-specific primers (oBTG-005-F, oBTG-027-R, oBTG-028-R) for the amplification of the ITS-5.8S rDNA region, we established the occurrence of C. subsalsa in fixed natural phytoplankton samples collected in coincidence with fish death events. Additionally, we established the presence of the recently discovered C. cf. subsalsa Adriatic genotype by analysing cellular cultures obtained from the same lagoon in 2013. This is the second worldwide record of C. cf. subsalsa Adriatic genotype. Our results revealed that the species-specific primers oBTG-005-F and oBTG-028-R distinguished this new genotype only when present singularly. This study provides valuable data that increase knowledge of C. subsalsa genotypes and of the long-term occurrence of Chattonella blooms in a transitional ecosystem through the use of samples up to 20 years oldopenStacca D.; Satta C.T.; Casabianca S.; Penna A.; Padedda B.M.; Sechi N.; Lugliè A.Stacca, D.; Satta, C. T.; Casabianca, Silvia; Penna, Antonella; Padedda, B. M.; Sechi, N.; Lugliè, A

Predimensionado simplificado de instalaciones solares de agua caliente sanitaria según los criterios y normativas básicas de arquitectura escolar

El trabajo propone tablas de predimensionado para instalaciones solares de agua caliente de uso sanitario para edificios escolares. Tomando como base los parámetros específicos de consumo, se determinaron consumos de agua caliente para algunas tipologías de escuelas, siguiendo los Criterios y Normativas Básicas de Arquitectura Escolar, en el proceso de instrumentación de la Ley Federal de Educación, definiendo los volúmenes de agua caliente y las áreas de captación necesarias para lograr temperaturas de uso del orden de los 45ºC, con rendimientos anuales próximos al 77%, para una localidad de Buenos Aires, utilizando el método f-chart. Se obtuvo así una serie de planillas que permiten el rápido predimensionado de las instalaciones solares para agua caliente de uso sanitario. Para determinar la fracción solar definitiva de cada instalación es necesario aplicar el método f-chart. Con estas planillas se puede establecer rápidamente las dimensiones de la instalación para facilitar su integración arquitectónica.The paper proposes tables for dimensioning solar hot water installations for use in school buildings. Taking as a base the specific consumption parameters, the hot water demand for different types of schools, based on the Criteria and Basic Standards od School Architecture, defining the volumes of hot water storage and the areas of solar collectors needed to achieve temperatures close to 45° C, with an annual solar fraction of about 77 %, for a location in Buenos Aires, Using the fchart method. In this way a series of tables were obtained that allow a rapid dimensioning for solar hot water installations. To obtain the exact solar fraction, the f-chart method should be applied. These tables allow the determination of dimensions of solar installations to encourage their integration in architectural design.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

High proliferation of Pseudo-nitzschia cf. arenysensis in the Adriatic Sea: ecological and morphological characterisation

The aim of the present study isto characterise the diatom Pseudo-nitzschia community during a bloom period together with environmental conditions. High proliferation of Pseudo-nitzschia spp. was observed in September 2017 at the shellfish breeding area in the Krka River estuary (Central eastern Adriatic Sea). The peak of abundance (1.8 x 106 cells L-1) was recorded at 7 m depth, and the increased abundance persisted for four weeks.Morphological analyses of field samples based on scanning electron microscopy (SEM) revealed that Pseudo-nitzschia cf. arenysensis was prevailing (94%) in the Pseudo-nitzschia assemblage. Several strains were successfully isolated from net samples in order to better define morphological features and phylogenetic characterisation. The isolated Pseudo-nitzschia strains corresponded morphologically to the P. cf. arenysensis from the field samples, based on our SEM observations. Phylogenetic analysis demonstrated that the Croatian strains grouped with P. arenysensis using the ITS and LSU rDNA sequences. Spearman rank correlation showed that salinity was an important environmental factor affecting the vertical distribution of Pseudo-nitzschia spp. in this highly variable area. Availability of increased concentration of orthophosphates and ammonium and low Si: TIN ratio may have promoted the bloom of P. cf. arenysensis in the estuary

The sxt Gene and Paralytic Shellfish Poisoning Toxins as Markers for the Monitoring of Toxic Alexandrium Species Blooms

Paralytic shellfish poisoning (PSP) is a serious human illness caused by the ingestion of seafood contaminated with saxitoxin and its derivatives (STXs). These toxins are produced by some species of marine dinoflagellates within the genus Alexandrium. In the Mediterranean Sea, toxic Alexandrium spp. blooms, especially of A. minutum, are frequent and intense with negative impact to coastal ecosystem, aquaculture practices and other economic activities. We conducted a large scale study on the sxt gene and toxin distribution and content in toxic dinoflagellate A. minutum of the Mediterranean Sea using both quantitative PCR (qPCR) and HILIC-HRMS techniques. We developed a new qPCR assay for the estimation of the sxtA1 gene copy number in seawater samples during a bloom event in Syracuse Bay (Mediterranean Sea) with an analytical sensitivity of 2.0 × 10° sxtA1 gene copy number per reaction. The linear correlation between sxtA1 gene copy number and microalgal abundance and between the sxtA1 gene and STX content allowed us to rapidly determine the STX-producing cell concentrations of two Alexandrium species in environmental samples. In these samples, the amount of sxtA1 gene was in the range of 1.38 × 105 − 2.55 × 108 copies/L and the STX concentrations ranged from 41−201 nmol/L. This study described a potential PSP scenario in the Mediterranean Sea.Versión del editor5,228