| Project/Area Number |
06660231
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
General fisheries
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| Research Institution | Tokyo University of Fisheries |
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Principal Investigator |
ISHIMARU Takashi Tokyo Univ.Fish., Dept.Fish., Assoc.Prof., 水産学部, 助教授 (90114371)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1994: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Diarrhetic shellfish poisoning / Dinoflagellates / Nutritional type |
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| Research Abstract |
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.
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