Studies of Okadaic Acid Related Compounds Produced by Bacteria

软海绵酸（OA）及其衍生物是引起贝类中毒（DSP）的主要物质。甲藻属（Dinophysis sp.）是引起DSP的甲藻。利马原甲藻是一种底栖甲藻，也已知具有DSP毒素。对这些甲藻中DSP毒素的生物合成知之甚少。从D. fortii，一种DSP-致病甲藻和P. lima的代表物种，用含有福尔马林的海水洗涤后。当通过HPLC分析时，在这些细菌的细胞提取物中未检测到OA或甲藻毒素（DTX）-1，但通过DSP毒素的酶联免疫吸附测定（ELISA）对相同样品的分析表明存在未知的OA相关化合物。与此相反，在其他细菌如弧菌属、芽孢杆菌属和大肠杆菌的细胞提取物中不识别与OA抗体的反应。从DSP-致病性甲藻分离的细菌中的OA相关化合物是水溶性的，相对高分子化合物。当用蛋白酶处理细菌细胞的匀浆时，在脂溶性提取物中识别OA相关化合物，其不同于OA或其已知衍生物如DTX 1或DTX 3。纯化后，从分离自P. lima的细菌的35 L培养物中获得7 mg与OA抗体反应的化合物。目前正在进行进一步的研究。

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.