New Trends in the Occurrence of Yessotoxins in the Northwestern Adriatic Sea

Abstract

Yessotoxins (YTXs) are polycyclic toxic ether compounds produced by phytoplanktonic dinoflagellates which accumulate in filter-feeding organisms. We know that the water temperature in our areas Northwestern Adriatic Sea is optimal for the growth of potentially toxic algae (around 20 °C). In recent years, these temperatures have remained at these levels for longer and longer periods, probably due to global warming, which has led to an excessive increase in toxin levels. The interruption of mussel harvesting caused by algae negatively affects farmers’ revenues and the availability of local fish, causing a major economic loss in Italy’s main shellfish sector. Methods: In the nine years considered, 3359 samples were examined: 1715 marine waters, 73 common clams; 732 mussels; 66 oysters; and 773 veracious clams. Bivalve molluscs were examined for the presence of marine biotoxins, including YTXs, while potentially toxic algae, including those producing YTXs, were searched for and counted in marine waters. The method adopted for the quantification of lipophilic toxins involves the use of an LC-MS/MS system. The enumeration of phytoplankton cells was performed according to the Utermhöl method. Results: Between 2012 and 2020, 706 molluscs were tested for YTXs. In total, 246 samples tested positive, i.e., 34.84%. Of the positive samples, 30 exceeded the legal limit. Conclusion: In this regard, it is essential to develop and activate, as soon as possible, an “early warning” system that allows a better control of the production areas of live bivalve molluscs, thus allowing an optimal management of the plants in these critical situations.

Alien Species Associated with New Introductions and Translocations of Commercial Bivalves in Italian Marine Waters

“…In fact, the intervalvular water of live animals and the water used to collect and transport the seeds may constitute a suitable environment for potentially toxic phytoplankton. This issue should be carefully assessed since the frequency and impact of harmful algal blooms and the toxin occurrence is a concrete and relevant problem for Italian shellfish production [123][124][125].…”

Dissolved Algal Toxins along the Southern Coast of British Columbia Canada

“…The only other study, of which we are aware, that involved the measurement of YTX in SPATT extracts was carried out in Chesapeake Bay and Virginia coastal bays; however, YTX was not detected at any sites or time points [ 23 ]. However, YTX has been identified in contaminated shellfish worldwide [ 74 , 75 , 76 ], including as the cause of a mass mortality event of abalone in California [ 77 ].…”

Natural Polyether Ionophores and Their Pharmacological Profile

“…Later, Protoceratium reticulatum, Lingulodinium polyedrum, Gonyaulax spinifera , and G. taylorii , were identified as the dinoflagellates that produce yessotoxin and its analogues ( 55 – 61 , structures seen in Figure 22 , and 3D graph seen in Figure 23 ) [ 100 , 101 ]. In addition to Japan, this toxin has been identified in shellfish harvested in Europe, including Spain, Italy, Norway, the Adriatic Sea, and the Sea of Japan, Russia; Chile; and New Zealand [ 102 , 103 ]. Yessotoxin and its analogues can induce programmed cell death at nanomolar concentrations in different model systems [ 104 ].…”