EU-LIFEHAB: Expanding the discussion on the life cycles of harmful algae

Versión del edito

The intricacies of dinoflagellate pellicle cysts: The example of Alexandrium minutum cysts from a bloom-recurrent area (Bay of Baiona,NW Spain)

The terms “temporary”, “pellicle,” and “ecdysal” cysts have been employed arbitrarily in the literature of the dinoflagellate life cycle to describe a non-motile and single-layered-wall stage with no mandatory dormancy period, of asexual or sexual origin. These three terms have been used more or less synonymously, but more specific definitions, taking into account morphological and physiological aspects and their roles in dinoflagellate population dynamics, are still needed. To clarify the current terminology, we examine and discuss the usages and foundations of those terms. The background for this discussion is provided by a comparison of the morphology and germination times of three different types of Alexandrium minutum cysts collected during a seasonal bloom in the Bay of Baiona (NW Spain). The double-walled cysts were similar to the resting cysts reported for this species, but other, thin-walled and thecate cysts were also observed. These latter cysts needed between 1 and 17 days to germinate and were therefore considered as short-term cysts, in contrast to the 1.5-month dormancy period of resting (hypnozygotic) cysts. Our results showed that the temporal distribution of these short-term cysts during the bloom period followed a pattern very similar to that of vegetative cells. However, resting cysts were only detected at the end of the bloom. In the context of our present knowledge regarding the dormancy and quiescence of dinoflagellate cysts, “temporary” is a very misleading and uncertain term and must be rejected. The term “ecdysal” has been used in reference to thin-walled cysts when ecdysis has been proved; however, ecdysis is not unique to this type of cysts as thick-walled zygotic cysts can be formed thorough ecdysis of a thecate planozygote. In conclusion, based on our current understanding of cysts, the term “pellicle” more appropriately describes single-layered-wall stages.Versión del editor2,277

Progresos en el conocimiento de los ciclos de vida de dinoflagelados y diatomeas productoras de proliferaciones algales nocivas

Las proliferaciones algales nocivas (PANs) son eventos recurrentes en aguas costeras de todos los países. Muchas especies algales tienen ciclos de vida complejos que incluyen fases con características morfológicas y fisiológicas muy diferentes. Por ejemplo: células y colonias, alternancia entre fases de dormición, tasas de crecimiento responsables de un incremento notable de la biomasa y quistes de resistencia. Los ciclos de vida tienen implicaciones importantes en la ocurrencia y la dinámica de las proliferaciones de las especies nocivas. En este trabajo se presentan las características principales de los ciclos de vida de los dinoflagelados y las diatomeas, haciendo énfasis en los aspectos relevantes y más recientes.Postprin

Assessment of microbial plankton diversity as an ecological indicator in the NW Mediterranean coast

High-throughput sequencing of microbial assemblages has been proposed as an alternative methodology to the traditional ones used in marine monitoring and environmental assessment. Here, we evaluated pico- and nanoplankton diversity as ecological indicators in NW Mediterranean coastal waters by comparing their diversity in samples subjected to varying degrees of continental pressures. Using metabarcoding of the 16S and 18S rRNA genes, we explored whether alphadiversity indices, abundance of Operational Taxonomic Units and taxonomic groups (and their ratios) provide information on the ecological quality of coastal waters. Our results revealed that only eukaryotic diversity metrics and a limited number of prokaryotic and eukaryotic taxa displayed potential in assessing continental influences in our surveyed area, resulting thus in a restrained potential of microbial plankton diversity as an ecological indicator. Therefore, incorporating microbial plankton diversity in environmental assessment could not always result in a significant improvement of current marine monitoring strategies.Preprint2,35

Analisi della biodiversità genetica di alcune specie microalgali responsabili di fioriture tossiche nel Mar Mediterraneo

In this study a genetic diversity of the main Mediterranean dinoflagellate HAB species has been analysed using the phylogeographic based approach. Different microalgal species isolates were characterized by phylogenetic, phylogeographic and population genetic aspects using different molecular markers and genetic analyses.S

Recomendaciones para la inclusión del género en los contenidos de investigación

Siguiendo las recomendaciones de las instituciones europeas de investigación, se debe plantear la investigación como un ciclo completo en el que se incluya el impacto de los resultados sobre la sociedad, la economía, las oportunidades de negocio, la creatividad, la innovación, el uso de recursos, los usuarios finales, el desarrollo local o global, el medioambiente, etc., y es en estos aspectos donde la inclusión de consideraciones de género aporta calidad a la investigación. El análisis sobre las distintas necesidades, actitudes y preferencias de ambos sexos incrementa la relevancia social y la calidad del avance científico alcanzado. La Comisión de Mujer y Ciencia ya señaló en 2015 y en 2018 la necesidad de recibir formación para la adecuada inclusión de las cuestiones de género en los contenidos de investigación. En este sentido, revisó el material disponible como herramientas para tal fin y promovió la impartición de un curso de formación interna del CSIC específico en la materia. En general, se encuentra gran dificultad (y también alguna resistencia) en la aplicación de la dimensión de género en los contenidos de investigación. La CMyC presenta esta guía informal como ayuda para completar las cuestiones de integración del género en los contenidos, de modo que sirvan de apoyo en la preparación de solicitudes tanto en las convocatorias nacionales como europeas, contribuyendo así a los objetivos del III Plan de Igualdad (Eje 7) y a la estrategia HRS4S (Acción 17) del CSIC.Peer reviewe

Large scale multifactorial likelihood quantitative analysis of BRCA1 and BRCA2 variants: An ENIGMA resource to support clinical variant classification

The multifactorial likelihood analysis method has demonstrated utility for quantitative assessment of variant pathogenicity for multiple cancer syndrome genes. Independent data types currently incorporated in the model for assessing BRCA1 and BRCA2 variants include clinically calibrated prior probability of pathogenicity based on variant location and bioinformatic prediction of variant effect, co-segregation, family cancer history profile, co-occurrence with a pathogenic variant in the same gene, breast tumor pathology, and case-control information. Research and clinical data for multifactorial likelihood analysis were collated for 1,395 BRCA1/2 predominantly intronic and missense variants, enabling classification based on posterior probability of pathogenicity for 734 variants: 447 variants were classified as (likely) benign, and 94 as (likely) pathogenic; and 248 classifications were new or considerably altered relative to ClinVar submissions. Classifications were compared with information not yet included in the likelihood model, and evidence strengths aligned to those recommended for ACMG/AMP classification codes. Altered mRNA splicing or function relative to known nonpathogenic variant controls were moderately to strongly predictive of variant pathogenicity. Variant absence in population datasets provided supporting evidence for variant pathogenicity. These findings have direct relevance for BRCA1 and BRCA2 variant evaluation, and justify the need for gene-specific calibration of evidence types used for variant classification

The use of flow cytometry for species identification and life-cycle studies in dinoflagellates

Publicado