Dinoflagellate Phylogeny as Inferred from Heat Shock Protein 90 and Ribosomal Gene Sequences

Interrelationships among dinoflagellates in molecular phylogenies are largely unresolved, especially in the deepest branches. Ribosomal DNA (rDNA) sequences provide phylogenetic signals only at the tips of the dinoflagellate tree. Two reasons for the poor resolution of deep dinoflagellate relationships using rDNA sequences are (1) most sites are relatively conserved and (2) there are different evolutionary rates among sites in different lineages. Therefore, alternative molecular markers are required to address the deeper phylogenetic relationships among dinoflagellates. Preliminary evidence indicates that the heat shock protein 90 gene (Hsp90) will provide an informative marker, mainly because this gene is relatively long and appears to have relatively uniform rates of evolution in different lineages.We more than doubled the previous dataset of Hsp90 sequences from dinoflagellates by generating additional sequences from 17 different species, representing seven different orders. In order to concatenate the Hsp90 data with rDNA sequences, we supplemented the Hsp90 sequences with three new SSU rDNA sequences and five new LSU rDNA sequences. The new Hsp90 sequences were generated, in part, from four additional heterotrophic dinoflagellates and the type species for six different genera. Molecular phylogenetic analyses resulted in a paraphyletic assemblage near the base of the dinoflagellate tree consisting of only athecate species. However, Noctiluca was never part of this assemblage and branched in a position that was nested within other lineages of dinokaryotes. The phylogenetic trees inferred from Hsp90 sequences were consistent with trees inferred from rDNA sequences in that the backbone of the dinoflagellate clade was largely unresolved.The sequence conservation in both Hsp90 and rDNA sequences and the poor resolution of the deepest nodes suggests that dinoflagellates reflect an explosive radiation in morphological diversity in their recent evolutionary past. Nonetheless, the more comprehensive analysis of Hsp90 sequences enabled us to infer phylogenetic interrelationships of dinoflagellates more rigorously. For instance, the phylogenetic position of Noctiluca, which possesses several unusual features, was incongruent with previous phylogenetic studies. Therefore, the generation of additional dinoflagellate Hsp90 sequences is expected to refine the stem group of athecate species observed here and contribute to future multi-gene analyses of dinoflagellate interrelationships

Reliable determination of Prorocentrum micans Ehrenb. (Prorocentrales, Dinophyceae) based on newly collected material from the type locality

The Prorocentrales are a unique group of dinophytes based on several apomorphic traits, but species delimitation is challenging within the group. The type species of Prorocentrum, namely P. micans, cannot be determined unambiguously, as important characters are not preserved in the original material collected in the first half of the 19th century. Water samples were taken at the type locality of P. micans in the Baltic Sea off Kiel (Germany) and strains with a morphology consistent with the protologue were established. An in-depth morphological analysis was performed, illustrating minute traits such as the periflagellar platelets and three different types of thecal pores. rRNA sequence data allowed for molecular characterization of the species. The newly collected material of P. micans was used for epitypification with the result that the type species of Prorocentrum can now be determined unambiguously

Morphology and phylogenetics of benthic prorocentrum species (Dinophyceae) from tropical Northwestern Australia

© 2019 by the authors. Approximately 70 species of Prorocentrum are known, of which around 30 species are associated with benthic habitats. Some produce okadaic acid (OA), dinophysistoxin (DTX) and their derivatives, which are involved in diarrhetic shellfish poisoning. In this study, we isolated and characterized Prorocentrum concavum and P. malayense from Broome in north Western Australia using light and scanning electron microscopy as well as molecular sequences of large subunit regions of ribosomal DNA, marking the first record of these species from Australian waters. The morphology of the motile cells of P. malayense was similar to P. concavum in the light microscopy, but differed by the smooth thecal surface, the pore pattern and the production of mucous stalk-like structures and a hyaline sheath around the non-motile cells. P. malayense could also be differentiated from other closely related species, P. leve and P. foraminosum, despite the similarity in thecal surface and pore pattern, by its platelet formula and morphologies. We tested the production of OA and DTXs from both species, but found that they did not produce detectable levels of these toxins in the given culturing conditions. This study aids in establishing more effective monitoring of potential harmful algal taxa in Australian waters for aquaculture and recreational purposes

Dinoflagellaten – ein Dauerexperiment der Evolution?

Dinoflagellaten haben nur eine oberflächliche Namensähnlichkeit mit den Dinosauriern (vom altgriechischen δεινός/ deinós = schrecklich); ihr Name leitet sich von dem altgriechischen δινος/dinos (wirbeln) ab und beschreibt die charakteristische Schwimmbewegung dieser mit dem bloßen Auge nicht direkt wahrnehmbaren Protisten. Die Bedeutung der sehr diversen und mit vielen faszinierenden Facetten aufwartenden Einzellergruppe ist nicht zu unterschätzen. So sind sie u. a. wichtige Produzenten und Konsumenten in aquatischen Nahrungsnetzen, Symbionten in Korallen, Parasiten mariner Organismen sowie dem Menschen gefährlich werdende Giftproduzenten. Auch morphologisch, biochemisch und genetisch besitzen Dinoflagellaten Besonderheiten, die sie zu einer der interessantesten eukaryotischen Gruppen machen

Correction to: Detection of the phycotoxin pectenotoxin-2 in waters around King George Island, Antarctica

A correction to this paper has been published: https://doi.org/10.1007/s00300-021-02834-3</jats:p

Detection of the phycotoxin pectenotoxin-2 in waters around King George Island, Antarctica

In order to set a base line for the observation of planktonic community changes due to global change, protistan plankton sampling in combination with phycotoxin measurements and solid phase adsorption toxin tracking (SPATT) was performed in two bays of King George Island (KGI) in January 2013 and 2014. In addition, SPATT sampling was performed in Potter Cove during a one-year period from January 2014 until January 2015. Known toxigenic taxa were not firmly identified in plankton samples but there was microscopical evidence for background level presence of Dinophysis spp. in the area. This was consistent with environmental conditions during the sampling periods, especially strong mixing of the water column and low water temperatures that do not favor dinoflagellate proliferations. Due to the lack of significant abundance of thecate toxigenic dinoflagellate species in microplankton samples, no phycotoxins were found in net tow samples. In contrast, SPATT sampling revealed the presence of dissolved pectenotoxin-2 (PTX-2) and its hydrolyzed form PTX-2 seco acid in both bays and during the entire one-year sampling period. The presence of dissolved PTX in coastal waters of KGI is strong new evidence for the presence of PTX-producing species, i.e., dinoflagellates of the genus Dinophysis in the area. The presence of phycotoxins and their respective producers, even at the low background concentrations found in this study, may be the seed of possible proliferations of these species under changing environmental conditions. Furthermore, phycotoxins can be used as chemotaxonomic markers for a very specific group of plankton thus allowing to track the presence of this group over time.Fil: Krock, Bernd. Alfred Wegener Institut-Helmholtz Zentrum für Polarund Meeresforschung; AlemaniaFil: Schloss, Irene Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Universidad Nacional de Tierra del Fuego; ArgentinaFil: Trefault, Nicole. Universidad de Santiago de Chile; ChileFil: Tillmann, Urban. Alfred Wegener Institut-Helmholtz Zentrum für Polarund Meeresforschung; AlemaniaFil: Hernando, Marcelo Pablo. Comisión Nacional de Energía Atómica; ArgentinaFil: Deregibus, Dolores. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Antoni, Julieta Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Almandoz, Gaston Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Hoppenrath, Mona. Alfred Wegener Institut-Helmholtz Zentrum für Polarund Meeresforschung; Alemani