Goniodomic Acid, a Transient Oxirane Intermediate in the Conversion of the Macrolide Algal Toxin Goniodomin A to Seco Acids.

The algal macrolide goniodomin A (GDA) undergoes ring-cleavage under unusually mild, alkaline conditions to form mixtures of stereoisomers of seco acids GDA-sa and iso-GDA-sa. In the primary fragmentation pathway, opening of the macrolide ring occurs by displacement of the carboxyl group by a base-catalyzed attack of the C32 hemiketal hydroxy group on C31, yielding an oxirane-carboxylic acid, named goniodomic acid. The oxirane ring is unstable, undergoing solvolytic opening to form mainly GDA-sa.

Effects of temperature, salinity and CO concentration on growth and toxin production of the harmful algal bloom species Alexandrium pseudogonyaulax (Dinophyceae) from the Danish Limfjord.

The marine dinoflagellate Alexandrium pseudogonyaulax is a widely distributed Harmful Algal Bloom (HAB) species that produces the macrocyclic polyketide goniodomin A (GDA). Occurrences in northern European waters are increasing and a spreading of the species along a salinity gradient into the Baltic Sea has been observed. As GDA is suspected to lead to invertebrate mortality, the spreading is of concern for the environment and possibly human health.

Azaspiracid-59 accumulation and transformation in mussels (Mytilus edulis) after feeding with Azadinium poporum (Dinophyceae).

Azaspiracid-59 (AZA-59) was detected in plankton in coastal waters of the Pacific Northwest USA. Given that bivalves metabolize and transform accumulated phycotoxins, a strain of Azadinium poporum isolated from the coast of Washington State that is a known producer of AZA-59 was used in a controlled feeding experiment with mussels (Mytilus edulis) to assess AZA-59 accumulation rates and transformation into shellfish metabolites. Mussels started feeding immediately after the addition of A.

Toxic effects of the emerging Alexandrium pseudogonyaulax (Dinophyceae) on multiple trophic levels of the pelagic food web.

The dinoflagellate Alexandrium pseudogonyaulax, a harmful algal bloom species, is currently appearing in increasing frequency and abundance across Northern European waters, displacing other Alexandrium species. This mixotrophic alga produces goniodomins (GDs) and bioactive extracellular substances (BECs) that may pose a threat to coastal ecosystems and other marine resources. This study demonstrated the adverse effects of A.