Description: The marine dinoflagellate Azadinium poporum produce azaspiracids (AZA) and has been recorded widely in the world. However, information on its biogeography is still limited, especially in view of the fact that A. poporum comprises several genetically differentiated groups. A total of 18 strains of A. poporum were obtained from the Eastern Mediterranean area by incubating surface sediment collected from Ionian Sea of Greece. The morphology of these strains was examined with light microscopy and scanning electron microscopy. Small subunit ribosomal DNA (SSU rDNA), large subunit ribosomal DNA (LSU rDNA) and internal transcribed spacer (ITS) sequences were obtained from all cultured strains. Molecular phylogeny based on concatenated SSU, LSU and ITS sequences confirmed three ribotypes within A. poporum and revealed two subclades within ribotypes A and C. Greek strains of A. poporum ribotype A were nested within ribotype A2 together with strains from Western Mediterranean Sea and French Atlantic, and Greek strains of A. poporum ribotype C were nested within ribotype C2 together with a strain from the Gulf of Mexico. Growth experiments on four selected strains revealed that ribotypes A and C from Greece differed in their growth at higher temperatures, indicating that they are physiologically differentiated. Azaspiracid profiles were analyzed for 15 cultured A. poporum strains using LCMS/MS and demonstrate that the A. poporum ribotype A from Greece produce low level or no AZA and A. poporum ribotype C from Greece produces predominantly AZA-40 (9.6–30.2 fg cell−1) followed by AZA-2 (2.1–2.6 fg cell−1). The first record of AZA-40 producing A. poporum from the Mediterranean suggests that this species is a potential source for azaspiracid contaminations in shellfish from the Eastern Mediterranean Sea.

Description: Amphidomataceae in the Labrador Sea and western Greenland waters Azaspiracids (AZA) are the most recently discovered group of lipophilic marine biotoxins of microalgal origin associated with human incidents of shellfish poisoning. Over the last couple of years, four out of 27 described species of Amphidomataceae have been identified as primary source of AZA. Diversity and global biogeography of species of Amphidomataceae, however, still are poorly known. In summer 2017 we sampled the central Labrador Sea and the western Greenland coast from Gothaab Fjord (64° N) to 75° N for the presence of Amphidomataceae and AZA. In the central Labrador Sea, light microscopy revealed the presence of small Azadinium-like cells at fairly high densities of 9,200 cells L-1. Single cell isolation from that station yielded 14 clonal strains representing four different species, Azadinium obesum, Az. trinitatum, Az. dexteroporum, and a new species which is currently described taxonomically. For all cultured strains, no known AZA at measureable amounts were detected. From all stations along the cruise, filtered seawater samples were negative for AZA. Specific qPCR assays for DNA samples, targeting ribosomal genes of Azadinium and Amphidoma, revealed positive signals from the majority of stations along the Greenland west coast indicating a not yet recorded widespread occurrence, albeit at low densities, of Amphidomataceen species in that area. Solid phase adsorption toxin tracking (SPATT) samplers were long-term deployed during the expedition in a continuous water sampling system (FerryBox) and were negative for known AZA. The results highlight the presence of Amphidomataceae in the area but the lack of toxins in the field samples indicate a currently low risk of toxic Amphidomataceae blooms in arctic coastal waters.

Description: Planktonic dinophyte species of the familiy Amphidomataceae attract attention as producers of azaspiracids, lipophilic phycotoxins that accumulate in shellfish and cause human health problem for shellfish consumers. About 30 species are describe, which are small and difficult to differentiate with routine light microscopy. These group of species is thus an obvious case where molecular methods for detection and quantification are needed. An overview is given on the state of the art and current use of qPCR assays for Amphidomataceae (Dinophyceae). New challanges related to quantification and assay specificity due to the continuously increasing diversity of species and strains are highlighted and discussed.