Studies on the Accumulation and Depuration Mechanism of Paralytic Shellfish Toxins by Bivalves.

为了研究麻痹贝类毒素（PST）在已知最有效积累的扇贝（Patinopecten yessoyensis）中的微分布，从肝胰脏中释放细胞，并采用HPLC测定毒素含量。在湿重基础上，细胞的毒性比整个器官高几倍，表明膜中存在运输系统膜，这可能在该物种的毒素积累中起重要作用。为了证实这一点，从肝胰腺中建立了原代细胞培养，并与毒素孵育。然而，没有证据表明细胞摄入毒素，可能是由于培养能力差。为了确定日本短颈蛤毒素的命运，在水箱中进行了有毒甲藻tamarense Alexandrium的饲养实验。通过对封闭系统中整个毒素分布的测定，包括交换的海水和粪便，揭示了该物种在毒素净化过程中分泌的作用比降解的作用更重要。对日本常见的9种双壳类动物的提取物进行体外培养实验，发现了PST降解酶，这在世界上尚属首次。

To study the micro-distribution of paralytic shellfish toxins (PST) in scallops Patinopecten yessoyensis, the species known to accumulate the toxin most effectively, cells were liberated from the hepatopancreas and measured for the toxin content by HPLC.The cells contained several folds higher toxicity than whole organs on wet weight base, indicating the presence of transporting system membrane in the membrane and this might play important role in the accumulation of the toxins by this species. To confirm this, the primary cell culture was established from the hepatopancreas and incubated with the toxins. However, no evidence was obtained as for the intake of the toxin by the cells, probably due to poor viability of the culture.To determine the fate of toxins in short-necked clam Tapes japonica, feeding experiments with toxic dinoflagellate Alexandrium tamarense were performed in a tank. Determination of entire toxin distribution in the closed system, including exchanged seawater and feces, revealed that secretion plays much more important role than degradation in the toxin depuration process by this species.In vitro incubation experiments on the extracts from 9 species of common bivalves in Japan resulted in the finding PST degradation enzyme(s) in a clam Peronidia venulosa, as the first case in the world.