2013 Fiscal Year Final Research Report
Evolution and origin of the chemical composition of radiolarian test during geologic time scale
| Project/Area Number |
23540545
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Stratigraphy/Paleontology
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| Research Institution | Tokyo Gakugei University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
TAKEMURA Akihiro 琉球大学, 理学部, 教授 (40222103)
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| Co-Investigator(Renkei-kenkyūsha) |
MAYAMA Shigeki 東京学芸大学, 教育学部, 教授 (40199914)
MATSUOKA Atsushi 新潟大学, 理学部, 教授 (00183947)
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| Project Period (FY) |
2011 – 2013
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| Keywords | 放散虫 / 硫酸ストロンチウム / シリカ / 骨殻 / 被殻 / 共生藻 / 渦鞭毛藻 |
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| Research Abstract |
Reproductive swarmers of the polycystine radiolarians were examined using light, scanning and transmission electron microscopy. The swarmer cells were about 8um in length with a pear-like shape and a conical end with two flagella. Lipid droplets and characteristically a vacuole-bound SrSO4 crystal were present in the cytoplasm. The morphological features and molecular phylogeny of the reproductive swarmers show evidence of ancestral traits of radiolarians; acantharians and polycystines have a common ancestry. Symbiotic dinoflagellate isolated from polycystine radiolarians was described using both natural and cultured materials. Motile cells were obtained in culture showed unarmored nature and the characteristics suggested it as Gymnodinium. Our results suggest that at least two dinoflagellate symbiont species existed in the radiolarians and they have been possibly reported as "Zooxanthella nutricula" since the 19th century.
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