|Budget Amount *help
¥3,200,000 (Direct Cost : ¥3,200,000)
Fiscal Year 1998 : ¥1,200,000 (Direct Cost : ¥1,200,000)
Fiscal Year 1997 : ¥2,000,000 (Direct Cost : ¥2,000,000)
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.