| Project/Area Number |
17KT0111
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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 | 特設分野 |
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| Research Field |
Constructive Systems Biology
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| Research Institution | Ehime University |
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Principal Investigator |
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| Project Period (FY) |
2017-07-18 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2018: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2017: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Keywords | 共生の進化 / 実験進化 / 藻類 / 大腸菌 / 原生動物 / 細胞内共生 / 生態系 / クロレラ / テトラヒメナ / 繊毛虫 / マイクロコズム / 進化 |
|---|
| Outline of Final Research Achievements |
Using a 13-year culture of an experimental ecosystem composed of three species (an alga, a bacterium, a ciliate), the evolutionary process of how an endosymbiotic association can evolve between unassociated alga and ciliate. Specifically, we tested the following, our original hypothesis using isolates of both species in the culture. “Endosymbiotic associations evolve between heterotrophic and photo-trophic organisms under resource-limited conditions produced in a mature-stage ecosystem, by which they raise exchanges of essential resources (quantity and quality) and reduce the dependency on the external sources such as bacteria for them.” The results indicated that the ciliate, originally survived/reproduced by consuming the bacterium, received essential resources of amino acids, vitamins, nucleotides, and sugars and became less dependent on bacterial cells. These results support the above hypothesis.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究は、13年に及ぶ実験生態系の長期培養系を解析し，従属栄養生物（繊毛虫）と光栄養生物（藻類）との間の細胞内共生の進化を実証的に解析したものであり，このような解析は国内外で他に例がない．従来の研究が共生をすでに進化させた生物を用いた解析であるのに対し，本研究ではモデル生態系の中で共生関係にない種間に共生が進化する過程を追跡するものである．“光照射下で自律的に存続する実験生態系モデル”は，そのツールとして有効であることを示した．このモデルは、進化を生態系過程との関わりにおいて理解する重要性の提起に加え，それを解析するツールとして他の研究者に影響を与えると考えられる．
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