Francisco Rodríguez

Genus Gambierdiscus in the Canary Islands (NE Atlantic Ocean) with description of Gambierdiscus silvae sp. nov., a new potentially toxic epiphytic benthic dinoflagellate.

Species of the dinoflagellate genus Gambierdiscus are the cause of Ciguatera Fish Poisoning, common in tropical areas. Nevertheless, until recently this syndrome was not reported in the NE Atlantic Ocean. A new photosynthetic dinoflagellate species, Gambierdiscus silvae sp. nov. is described based on samples taken from tide pools on rocky shores of the Canary Islands (NE Atlantic Ocean). Its morphology was studied by light and scanning electron microscopy. The new species is anterioposteriorly compressed, lenticular in shape with an epitheca slightly higher than the hypotheca. It is round in apical view and has a thick smooth theca with many scattered pores. Plate formula is Po, 4, 0a, 6″, 6c, 6s?, 5″, 0p, 2″″. Plate 2 is hatchet-shaped and Plate 2″″ is very wide and the largest of the hypotheca. Phylogenies inferred from the large subunit nuclear rRNA showed that three G. silvae strains clustered in a well supported sister clade to G. polynesiensis, distinct from the other species. G. australes was observed for the first time in the Atlantic, together with G. excentricus already reported from these islands. This work increases the number of Gambierdiscus species described and shows their unexpected diversity in the Canary Islands.

Review of the main ecological features affecting benthic dinoflagellate blooms

Abstract Both benthic and planktic dinoflagellates can produce harmful algal blooms. However most of the studies conducted so far emphasized on planktic species. In the present review, we assessed the main ecological factors affecting the population dynamics of bloomforming benthic dinoflagellates, with particular emphasis on Ostreopsis and Gambierdiscus. Based on the basic equation of population dynamics, we mainly focused on growth, predation, mortality, immigration and dispersion. Factors determining the dynamics of benthic dinoflagellate populations are very different from the well-studied case of planktic dinoflagellates. The relative movement of cells and water is the main difference as benthic dinoflagellates depend on a fixed substratum while planktic dinoflagellates depend on a water body. Any alteration in the substratum will affect benthic dinoflagellate populations, as for example the changes in seaweeds concentrations due to predation by sea urchins. We also evaluated the impact of global changes on dinoflagellates bloom occurrence.

Management of Ostreopsis Blooms in Recreational waters along the Catalan Coast (NW Mediterranean Sea): Cooperation between a Research Project and a Monitoring Program

Abstract n As shown in this report, the integration of a research project with a monitoring program improves the detection and management of Ostreopsis blooms in Catalonia. The research project benefits from information previously obtained from several localities by the monitoring program, which in turn profits from the specific findings and conclusions contributed by the research project.

The genus Ostreopsis along the Algerian coastal waters (SW Mediterranean Sea) associated with a human respiratory intoxication episode

Abstract n This work describes the first toxic event (human intoxications and sea urchin mortality) related to Ostreopsis bloom in Algerian coastal waters. The distribution of Ostreopsis is presented in three rocky beaches of Algiers Wilaya, where several cases of human intoxications were registered during July 2009. The maximum abundances attained by Ostreopsis in other stations of the network established by the Agency for the Protection and Promotion of Algiers Wilaya coasts (APPL) for monitoring HABs species are also presented. We discuss some of the factors that could explain this toxic episode.

Ribosomal DNA Organization Patterns within the Dinoflagellate Genus Alexandrium as Revealed by FISH: Life Cycle and Evolutionary Implications.

Dinoflagellates are a group of protists whose genome differs from that of other eukaryotes in terms of size (contains up to 250pg per haploid cell), base composition, chromosomal organization, and gene expression. But rDNA gene mapping of the active nucleolus in this unusual eukaryotic genome has not been carried out thus far. Here we used FISH in dinoflagellate species belonging to the genus Alexandrium (genome sizes ranging from 21 to 170 pg of DNA per haploid genome) to localize the sequences encoding the 18S, 5.8S, and 28S rRNA genes. The results can be summarized as follows: 1) Each dinoflagellate cell contains only one active nucleolus, with no hybridization signals outside it. However, the rDNA organization varies among species, from repetitive clusters forming discrete nuclear organizer regions (NORs) in some to specialized ribosomal chromosomes in other species. The latter chromosomes, never reported before in other eukaryotes, are mainly formed by rDNA genes and appeared in the species with the highest DNA content. 2) Dinoflagellate chromosomes are first characterized by several eukaryotic features, such as structural differentiation (centromere-like constrictions), size differences (dot chromosomes), and SAT (satellite) chromosomes. 3) NOR patterns prove to be useful in discriminating between cryptic species and life cycle stages in protists.

First report of the toxin profile of Dinophysis sacculus Stein from LC-MS analysis of laboratory cultures

Dinophysis sacculus is associated with DSP outbreaks especially in the Mediterranean Sea and is supposed to be mildly toxic based on few toxin results from field samples. First report of LC-MS analysis of D. sacculus cultures from Galicia (NW Spain) showed moderate amounts of OA (7.8xa0pgxa0cell(-1)) comparable to those found in Dinophysis acuminata from the same region, PTX2 (13.2xa0pgxa0cell(-1)) and trace amounts of DTX1 (0.8xa0pg OA equiv. cell(-1)). The contribution of D. sacculus to DSP outbreaks in the Galician Northern Rías should not be underestimated.

High performance liquid chromatographic separation of chlorophyllc forms from marine phytoplankton on octylsilica bonded phases

SummaryThe separation of mono- and divinyl chlorophyllc forms was estudied employing several octylsilica and octadecylsilica columns under isocratic conditions. In this paper we show that, using the adequate mobile phases, the monomeric C8 columns can separate the mentioned chlorophylls. A comparison between C8 and C18 columns reveals that monomeric OS phases provide always higher resolution of the MV- and DV chlorophyllc pairs. Such a result could be explained in terms of differences in column polarity. When adequate gradient profiles and injection conditions are used the separation is accomplished together with that of other chlorophylls and carotenoids.

Distribution, occurrence and biotoxin composition of the main shellfish toxin producing microalgae within European waters: A comparison of methods of analysis.

Harmful algal blooms (HABs) are a natural global phenomena emerging in severity and extent. Incidents have many economic, ecological and human health impacts. Monitoring and providing early warning of toxic HABs are critical for protecting public health. Current monitoring programmes include measuring the number of toxic phytoplankton cells in the water and biotoxin levels in shellfish tissue. As these efforts are demanding and labour intensive, methods which improve the efficiency are essential. This study compares the utilisation of a multitoxin surface plasmon resonance (multitoxin SPR) biosensor with enzyme-linked immunosorbent assay (ELISA) and analytical methods such as high performance liquid chromatography with fluorescence detection (HPLC-FLD) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) for toxic HAB monitoring efforts in Europe. Seawater samples (n=256) from European waters, collected 2009-2011, were analysed for biotoxins: saxitoxin and analogues, okadaic acid and dinophysistoxins 1/2 (DTX1/DTX2) and domoic acid responsible for paralytic shellfish poisoning (PSP), diarrheic shellfish poisoning (DSP) and amnesic shellfish poisoning (ASP), respectively. Biotoxins were detected mainly in samples from Spain and Ireland. France and Norway appeared to have the lowest number of toxic samples. Both the multitoxin SPR biosensor and the RNA microarray were more sensitive at detecting toxic HABs than standard light microscopy phytoplankton monitoring. Correlations between each of the detection methods were performed with the overall agreement, based on statistical 2×2 comparison tables, between each testing platform ranging between 32% and 74% for all three toxin families illustrating that one individual testing method may not be an ideal solution. An efficient early warning monitoring system for the detection of toxic HABs could therefore be achieved by combining both the multitoxin SPR biosensor and RNA microarray.

Notes on Ostreopsis sp. from southern-central coast of Cuba

Abstract n In order to investigate the identity, abundance and toxicity of a distinctive Ostreopsis species present in the southern-central coast of Cuba, Ostreopsis field populations were examined during January-September of 2010. The morphological and partial LSU phylogenetic data suggested the presence of O. lenticularis, although a very close species like O. labens could not be discarded. Results indicated the presence of palytoxin-like molecules in a natural extract at concentration of 0.12 pg/cell. Ostreopsis populations were very stable through the course of the study, and a maximum of 7.9 × 104 cells/g of macroalgae fresh weight was recorded on June.

Metabolomic Profiles of Dinophysis acuminata and Dinophysis acuta Using Non-Targeted High-Resolution Mass Spectrometry: Effect of Nutritional Status and Prey

Photosynthetic species of the genus Dinophysis are obligate mixotrophs with temporary plastids (kleptoplastids) that are acquired from the ciliate Mesodinium rubrum, which feeds on cryptophytes of the Teleaulax-Plagioselmis-Geminigera clade. A metabolomic study of the three-species food chain Dinophysis-Mesodinium-Teleaulax was carried out using mass spectrometric analysis of extracts of batch-cultured cells of each level of that food chain. The main goal was to compare the metabolomic expression of Galician strains of Dinophysis acuminata and D. acuta that were subjected to different feeding regimes (well-fed and prey-limited) and feeding on two Mesodinium (Spanish and Danish) strains. Both Dinophysis species were able to grow while feeding on both Mesodinium strains, although differences in growth rates were observed. Toxin and metabolomic profiles of the two Dinophysis species were significantly different, and also varied between different feeding regimes and different prey organisms. Furthermore, significantly different metabolomes were expressed by a strain of D. acuminata that was feeding on different strains of the ciliate Mesodinium rubrum. Both species-specific metabolites and those common to D. acuminata and D. acuta were tentatively identified by screening of METLIN and Marine Natural Products Dictionary databases. This first metabolomic study applied to Dinophysis acuminata and D.acuta in culture establishes a basis for the chemical inventory of these species.