2022 Fiscal Year Final Research Report
Elucidation of the significance of cyanobacterial circudian clook in aquatic ecosystems
| Project/Area Number |
18K05797
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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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| Review Section |
Basic Section 40030:Aquatic bioproduction science-related
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| Research Institution | Ryukoku University |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2023-03-31
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| Keywords | 湖沼生態系 / 藻類 / 生物時計 / 理論モデル / 鉛直移動 |
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| Outline of Final Research Achievements |
Cyanobacteria are phototrophic bacteria, part of which possesses circadian clock genes. Previous studies focused on the biochemistry, and the ecological and evolutionary studies are limited. In particular, it is still to be elucidated what brings the adaptive advantages to cyanobacteria. In this study, we revealed that the vertical migrations of cyanobacteria in lakes include diurnal, bidiurnal, and chaotic vertical oscillations by using a mathematical model. The results suggest primary production by cyanobacteria can be unstable unless the photosynthesis rate is controlled by the circadian clock, which in turn, diurnal migration controlled by the circadian clock may provide adaptive advantages to cyanobacteria in lakes.
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| Free Research Field |
微生物生態学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究は自然生態系の淡水域のシアノバクテリアの時計遺伝子に注目した点，および一次生産者の概日時計の役割を明らかにすることを試みる点が，先行研究と比較して，独自性・創造性が高い．これまで水域生態系の基盤をなす植物プランクトンの動態，例えば植物プランクトン種組成の季節変化といった現象を考える際，食物網におけるトップダウン効果とボトムアップ効果のバランスで考えられてきたが，さらに内生リズムが重要な役割を果たす可能性がある．本研究の成果は「時計遺伝子はプランクトン態のシアノバクテリアでは維持されているが，付着態などのシアノバクテリアでは適応的意義が少なく失われている」といった検証可能な予測を与える．
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