2012 Fiscal Year Final Research Report
The study on parasitism of the eugregarinid protozoan to the Antarctic crustaceans
| Project/Area Number |
22770025
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Ecology/Environment
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| Research Institution | National Institute of Polar Research |
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Principal Investigator |
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| Project Period (FY) |
2010 – 2012
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| Keywords | 種間関係 / 寄生 |
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| Research Abstract |
The eugregarinid protozoan, Cephaloidophora pacifica Avdeev (Order Eugregarinorida, Family Cephaloidophoridae) has previously been found in the digestive tract of Antarctic krill, Euphausia superba. Two Antarctic euphausiid species, E. superba and ice krill E. crystallorophias, often overlap in distribution in Antarctic coastal regions. Two eugregarinid parasites (C. pacifica and Eugregarine A) were found in the digestive tract of E. crystallorophias. The results of sequences of Eugregarine A appeared as a nearest sister group of C. pacifica. C. pacifica were found form both host species with over 90% of prevalence, and showed a remarkably wide range in numbers. They were observed to accumulate in the front section of the digestive tract. Mean intensities of eugregarines showed high value in the E. superba compared with the E. crystallorophias. Host body length appears to be the most important factor determining the intensity of C. pacifica regardless of the difference in host species. On the other hand, Eugregarine A was not found from E. superba.
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