BIOACCUMULATION OF PARALYTIC SHELLFISH POISONING (PSP) TOXINS FROM THE CYANOBACTERIUM ANABAENA CIRCINALIS BY THE FRESHWATER MUSSEL ALATHYRIA CONDOLA

摘要

The Australian freshwater mussel Alathyria condola accumulated high levels of paralytic shellfish poisoning (PSP) toxins when fed the neurotoxic cyanobacterium Anabaena circinalis, shown recently to contain high concentrations of C-toxins and gonyautoxins. Significant accumulation (>80 mu g/100 g of mussel flesh) was detected following 2-3 days exposure to water containing 2x10(5) cells/ml A. circinalis. Only trace accumulation of PSP toxins was demonstrated over long-term (5 week) exposure at low concentration (c. 10(4) cells/ml). The relative abundance of C-toxins, gonyautoxins and saxitoxins in mussels generally matched the toxin profiles of the dietary A. circinalis, although there were differences in the GTX2/3 and C1/2 ratios with time, and an increase in abundance of decarbamoylgonyautoxins. Analysis of mussel tissues after 7 days, exposure to A. circinalis revealed that 96% of the toxins were accumulated in the viscera. As in marine waters, the bioaccumulation of PSP toxins in freshwater mussels may pose a health risk to humans and animals, especially in areas where seasonally decreasing water levels expose mussel beds to surface scums of toxic cyanobacteria. [References: 35]