Azadinium spinosumgen. et sp. nov. (Dinophyceae) identified as a primary producer of azaspiracid toxins

Abstract

Azaspiracids (AZAs) are a group of lipophilic marine biotoxins associated with human incidents of shellfish poisoning. During a research cruise to the North Sea, we analysed size-fractionated plankton for AZA by mass spectrometry and successfully isolated an AZA-producing dinoflagellate from the east coast of Scotland. As shown previously, an axenic culture of this dinoflagellate produces AZA 1, AZA 2 and an isomer of AZA 2. Here we give a taxonomic description of this new taxon Azadinium spinosum gen. et sp. nov., as a de novo producer of AZAs. Azadinium spinosum is a small (12-16 mm length and 7-11 mm width) peridinin-containing photosynthetic dinoflagellate with a superficial resemblance under light microscopy to gymnodinioids, but with a thin theca. The large nucleus is spherical and located posteriorly, whereas the single chloroplast is parietal, lobed, and typically extends into both the epi-and hyposome. The Kofoidian thecal tabulation is APC, 4 0 , 3a, 6 00 , 6C, 5?S, 6 000 , 2 0000 . This plate pattern has an epithecal affinity to the Peridiniales and a hypothecal affinity to the Gonyaulacales, but is distinctly different from described dinoflagellate genera. The assignment of A. spinosum to the dinoflagellates is supported by molecular phylogenetic analysis of four genes, SSU rDNA, LSU rDNA (D1/D2 region), ITS and cytochrome oxidase (subunit 1) (COI). In agreement with the morphological description, phylogenetic analysis did not show any particularly close affiliation to the Peridiniales or Gonyaulacales, nor to any other dinoflagellate order represented in molecular databases. Consequently, we erected a new genus, Azadinium, for this taxon. However the ordinal affiliation of the genus is uncertain. This study represents the first description and confirmation of a new dinoflagellate species capable of producing AZA and is thus an important advance in surveillance programmes for toxigenic microalgae and toxins of human health significance.

The first report ofVulcanodinium rugosum(Dinophyceae) from the South China Sea with a focus on the life cycle

“…Characters of these two orders were also shared by species in the genera of Azadinium Elbra¨chter and Tillmann, Amphidoma Stein and Bysmatrum Faust and Steidinger (Faust & Steidinger 1998;Tillmann et al 2009;Tillmann et al 2012). Despite morphological similarities, Bysmatrum is phylogenetically distant from Vulcanodinium (Fig.…”

Azadinium poporum from the Argentine Continental Shelf, Southwestern Atlantic, produces azaspiracid-2 and azaspiracid-2 phosphate

“…Morphology, light-and electron microscopy A number of small dinoflagellate cells (as identified at low magnification by shape and swimming patterns) were observed in wells with sediment samples after about 1½ weeks of incubation. Among those, Azadinium-like cells as defined by their conspicuous swimming pattern (see accompanying video in Tillmann et al, 2009) were isolated as single cells, and from these 10 clonal cultures of Azadinium were obtained. Light-and electron microscopy of all isolates confirmed that they all were identical in terms of morphology and that they all represented the species Azadinium poporum.…”

A new non-toxic species in the dinoflagellate genusAzadinium:A. poporumsp. nov.

“…However, the toxins, and thus presumably the causative organism(s), are widely distributed, mainly in western Europe (Satake et al, 1998;James et al, 2002;Bran˜a Magdalena et al, 2003;Vale et al, 2008), but also on the coast of Morocco (Taleb et al, 2006) and northern Chile (Alvarez et al, 2010). Subsequent to the erroneous attribution of AZA toxins to the heterotrophic marine dinoflagellate Protoperidinium crassipes as the primary source organism (James et al, 2003a), rather than merely as a toxin vector, the culprit for AZA production was recently unambiguously identified and described as a novel species within a newly created genus Azadinium Elbra¨chter & Tillmann Tillmann et al, 2009). The toxigenic type species, a small photosynthetic dinoflagellate, described as Azadinium spinosum Elbra¨chter & Tillmann, was isolated off the Scottish east coast, but was also detected by molecular methods in samples from the Danish coast , indicating a wide distribution in the North Sea.…”