A new Alexandrium ostenfeldii strain from Peru: First report of 13-desmethyl spirolide C, and a unique paralytic shellfish toxin profile

Tenorio C.; Álvarez G.; Araya M.; Rossignoli A.E.; Blanco J.; Arakaki N.; Pérez-Alania M.; Díaz P.A.; Uribe E. · Marine Pollution Bulletin (2026) · DOI: 10.1016/j.marpolbul.2025.118938

Resumen

Alexandrium species are among the most frequently reported in harmful algal blooms (HABs), posing risks to both the environment and human health. During a study of a bloom event in Paracas Bay in the austral autumn of 2018, a dinoflagellate of the genus Alexandrium was detected in phytoplankton samples, and a clonal culture was established. Morphological analyses identified A. ostenfeldii , which was confirmed by phylogenetic analyses based on the LSU rDNA D1/D2 regions, confirming that strain IMP-BG-507 clustered with strains isolated from El Callao and Chilean Patagonia belonging to sub-clade 6. LC-MS analyses revealed an atypical Paralytic Shellfish Toxin profile dominated by dcSTX, dcGTX3, and dcGTX2, followed by doSTX, doGTX2, and doGTX3. Additionally, LC-HRMS revealed the presence of 13-desmethyl spirolide C, which is the first report of this toxin in an A. ostenfeldii strain isolated from the Pacific coast of South America. The unique toxin profile of strain IMP-BG-507 reveals the need to continue studies on different strains and populations of A. ostenfeldii and to deepen the search for new species of the Alexandrium genus that could affect aquaculture development on the coasts of Peru.

Instituciones: Universidad Nacional Agraria La Molina