Biotransformation Of Paralytic Shellfish Toxins In Shellfish And Effect On Its Immune System

Paralytic Shellfish Poisoning（PSP）is a group of important marine biotoxinsproduced by the harmful dinoflagellate. Eating PSP contaminated seafood can causehuman poisoning. PSP toxins can also be serious pollution of fishery resources,causeing huge economic losses to the shellfish mariculture. In recent years, PSP’s newcompounds M1-M4is detected in some of the toxic dinoflagellate contaminatedshellfish samples. It is known that the toxin-producing dinoflagellates do not producesuch compounds, indicating that these compounds may be the metabolites or chemicaldegradation products in the process of PSP detoxification in shellfish. The Mcompounds also detected in the scallop （Patinopecten yessoensis） and clams samplescollected from the Northern Yellow Sea in our country. Therefore it has greatsignificance to investigate the biotransformation process and variation of the immunesystem activity after shellfish accumulate PSP toxins, for revealing the detoxificationof shellfish PSP toxin mechanism.In this study, the food chain of scallops and Mussels eating Alexandriumtamarense （Producing PSP toxins） are simulated indoors. The activity of reactiveoxygen species （ROS），superoxide dismutase （SOD）,Catalase （CAT） and glutathioneperoxidase （GSH-Px） in the shellfish digestive gland and muscle tissues aremonitored. At the same time the transformation process of the toxins in the scalloptissue during the shellfish accumulate PSP toxins is monitored using LC-MS/MSmethod in order to explore the relationship between the transformation of toxin andthe activity of the immune system response during the process of shellfishaccumulation PSP toxin. Accumulate the data for revealing possible shellfish PSPtoxin detoxification mechanism.The result shows that the feeding process of scallops and mussels withtoxin-producing dinoflagellates can produce ROS oxidative damage, leading ROSconcentration rise. The antioxidant system of scallops and mussels show certain differences in the process of removal the ROS, including the SOD activity of scalloptissue is inhibited, but the digestive gland tissue with high CAT activity, which canbe used to clear up the H₂O₂in the body; however the SOD and CAT enzymeactivities of mussels tissue are activated, effectively scavenging superoxide anionfree radical and H₂O₂. The GSH-Px activity of scallop and mussels tissue is alsoactivated by ROS, and the variation and the variation range of the activity aresimilarity, may restrictby the process of glutathione depletion and regeneration.Toxin analysis results show that, after scallop feeding with Alexandrium tamarense,PSP toxins can rapidly accumulated in the scallop digestive gland tissue, but PSPtoxins are not distributed into the muscle tissue during96hours exposure and72hours detoxification. PSP toxins in the scallops take biotransformation and productlow toxic metabolites M1, M3, M5, M7and M9, shows that the C-11bit of C1/2andC3/4toxin is more proned to the sulfation reaction.