| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1999: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1998: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
The causative compounds of diarrhetic shellfish poisoning (DSP) are okadaic acid (OA) and its derivatives. Dinophysis sp. Are reported to be the causative dinoflagellates of DSP. Prorocentrum lima, a benthic dinoflagellate are also known to possess DSP toxins. Little is known on the biosynthesis of DSP toxins in these dinoflagellates. We obtained each one gram-positive bacterium from D. fortii, a representative species of DSP-causative dinoflagellate and P. lima, after washed with seawater containing formalin. OA nor dinophysistoxin (DTX)-1 were not detected in the cell extracts of these bacteria when analyzed by HPLC, but analysis of the same samples by enzyme linked immnosorbent assay (ELISA) on DSP toxins suggested that unknown OA-related compound(s) are present. In contrast, no reaction with OA antibody was recognized in the cell extracts of other bacterium such as Vibrio sp, Baclius sp nor Esherichia coli. The OA-related compound in the bacteria isolated from the DSP-causative dinoflagellate are water-soluble, relatively high molecule compounds. When the homogenates of bacterial cells were treated with protease, OA-related compounds are recognized in lipid-soluble extract, which are different from OA or its known derivatives such as DTX1 or DTX3. After purification, 7 mg of a compound which reacts with OA antibody was obtained from 35 L culture of a bacterium isolated from P. lima. Further studies are now under progress.
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