Nutritional types of the causative organisms of diarrhetic shellfish poisonings

甲藻属（Dinophysis spp.）是引起贝类中毒的甲藻，它的藻胆素呈橙子荧光，可将隐藻保持在其细胞内。在先前的研究中，我们检测到甲藻能摄取隐藻，但我们不能将甲藻与之混合培养。在本研究中，我们试图通过与一些纳米鞭毛虫和/或有机营养物的分离物培养来确定尖甲藻的营养类型。在东京湾每月进行D. acuminata和其他纳米鞭毛虫的采样。建立了6株斜叠藻属和2株绿藻属的塔单胞菌。将尖鞭金藻接种到新收集的含有用各种筛孔大小的过滤器分级的微生物的海水中，并且还接种到具有每种纳米鞭毛虫分离物的过滤灭菌海水中。天然海水中的一些生物被尖头水蚤摄入，但没有培养的纳米鞭毛虫。尖叶石斛在混合培养中色素的保存时间比在含有机营养物和不含有机营养物的培养基中的要长。然而，它在具有纳米鞭毛的培养物中没有显示出生长。在含乙醇酸的培养基中，尖毛藻生长缓慢，但存活时间不超过2个月。尖毛藻在斜抱蕨上没有表现出与直毛藻和尾毛藻相同的趋化行为，但在与斜抱蕨的混合培养中，其细胞色素保持时间较长。尖突腹小蜂也可能摄食斜带蕨，但其行为与营养类型的关系尚不清楚。

Some species of the causative dinoflagellate of diarrhetic shellfish poisonings, Dinophysis spp.are known to have orange fluorescence of phycobilin and thought to keep cryptophyceans in their cells as simbionts. In the previous study, we detected that Dinopysis spp.ingest a cryptophycean, Plagioselmis sp.but we could not keep Dinophysis in mixed culture with it.In this study, we tried to confirm the nutritional type of Dinophysis acuminata by culturing with some isolates of nanoflagellates and/or organic nutrients. Samplings of D.acuminata and other nanoflagellates have been conducted monthly in Tokyo Bay. Six strains of Plagioselmis spp.and two strains of prasinophyceans, Pyramimonas spp.were established. D.acuminata was inoculated into newly collected seawater containing microorganisms fractionated with various mesh-sized filter and also into filter sterilized seawater with each isolate of nanoflagellate. Some organisms in natural seawater were filmed to be ingested by D.acuminata, but no cultured nanoflagellates. D.acuminata kept their pigment longer in mixed culture than in culture media with and without organic nutrients. However, it did not show growth in culture with nanofalagellates. Slight growth was observed in culture medium with glycolic acid but D.acuminata did not survive more than two months in it.D.acuminata did not show the ingesting behavior on Plagioselmis which was seen in D.fortii and D.caudata, but it keeps cellular pigment longer in mixed culture with some strains of Plagioselmis. D.acuminata might also ingest Plagioselmis but the relationship between the behavior and the nutritional type is still obscure.