This study demonstrates how UCT’s aminopropyl SPE cartridges provided reliable sample cleanup for sensitive LC-MS/MS detection of ciguatoxins (CTXs) and related metabolites in shellfish tissues. Ciguatera poisoning (CP) is the world’s most common non-bacterial illness, caused by CTXs mainly produced by benthic dinoflagellates.
These neurotoxins are usually transferred through herbivorous fish but can also accumulate in marine invertebrates. This study investigated whether temperate green-lipped mussels (Perna canaliculus), can accumulate CTXs, how rapidly they depurate them, and whether exposure affects the physiology of green-lipped mussels. Two laboratory feeding experiments were conducted using green-lipped mussels exposed to the toxic dinoflagellate, Gambierdiscus polynesiensis:
On each sampling day, mussels were weighed, measured, and dissected. Gill tissue was collected for transcriptomic analysis, while digestive tissues and remaining tissues (“rest”) were separated for toxin analysis. Toxin extraction followed Murray et al. (2018). Briefly, homogenized tissues were extracted with 60% aqueous methanol, heated, centrifuged, partitioned with dichloromethane (DCM), and evaporated under nitrogen before cleanup. Samples were purified using UCT’s aminopropyl solid-phase extraction cartridges (CUNAX123; 200 mg/3 mL), then analyzed by LC-MS/MS. Samples were screened for multiple algal CTXs, biotransformed CTX metabolites, gambierone, and 44-methylgambierone. Statistical analyses were conducted in R, including a log linear regression model to evaluate CTX depuration over time.
Results showed that green-lipped mussels rapidly accumulated CTXs, primarily in the digestive system, reaching concentrations above the U.S. Food and Drug Administration guidance value of 0.01 µg kg⁻¹ CTX-1B equivalents and exceeding 5 µg kg⁻¹ total CTXs. However, mussels also rapidly depurated toxins and showed complete toxin elimination after 35 days on a toxin-free diet. Transcriptomic analyses revealed delayed stress, detoxification, and immune responses associated with CTX exposure.
These findings highlight potential risks for seafood safety monitoring and harvest management in regions where CTX producing algal blooms may expand due to climate change. Further research is needed to better define bioaccumulation rates across shellfish species and improve monitoring strategies.
Reference:
Smith, K. F.; Rhodes, L. L.; Curley, B.; Verma, A.; Kohli, G.; Harwood, D. T.; Murray, J. S.; Viallon, J.; Darius, H. T.; Chinain, M.; Rongo, T.; Hosking, J.; Argyle, P. A.; Stuart, J.; Murray, S. A. Accumulation and Depuration of Ciguatoxins in Green-Lipped Mussels Fed Toxic Gambierdiscus polynesiensis: Evidence from Controlled Feeding and Transcriptomic Analysis. Ecotoxicol. Environ. Saf. 2026, 315, 120096. https://doi.org/10.1016/j.ecoenv.2026.120096