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

为了研究麻痹性贝类毒素(PST)在扇贝体内的微分布，从肝胰腺中解放细胞，用高效液相色谱仪(HPLC)测定细胞中的毒素含量。在湿重的基础上，细胞的毒性是整个器官的几倍，表明膜上存在转运系统膜，这可能在该物种毒素的积累中起着重要作用。为了证实这一点，从肝胰腺建立了原代细胞培养，并与毒素一起孵育。然而，没有获得细胞摄取毒素的证据，这可能是由于培养物的生存能力较差。为了确定毒素在短颈文蛤中的命运，在水箱中进行了有毒的塔玛亚历山大藻的摄食实验。对封闭系统中包括交换海水和粪便在内的整个毒素分布的测定表明，在该物种的毒素净化过程中，分泌作用比降解作用要大得多。对日本9种常见双壳贝类的提取物进行体外孵育实验，在文脉贻贝体内发现了PST降解酶(S)，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.