Studies to settle the mystery whether chlorophyll e exists in nature

Research Project

Project/Area Number	18K19339
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 44:Biology at cellular to organismal levels, and related fields
Research Institution	Kyoto University
Principal Investigator	Miyashita Hideaki 京都大学, 人間・環境学研究科, 教授 (50323746)
Project Period (FY)	2018-06-29 – 2022-03-31
Project Status	Completed (Fiscal Year 2021)
Budget Amount *help	¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000) Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000) Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000) Fiscal Year 2018: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Keywords	クロロフィルｅ / 黄緑藻類 / クロロフィラーゼ / クロロフィルe / 黄緑藻 / クロロフィル e
Outline of Final Research Achievements	In this study, we aimed to solve the mystery of the existence of chlorophyll (Chl) e. We attempted to test three hypotheses: (1) Chl e may be a by-product during the pigment extraction; (2) Chl e may have been produced not by the xanthophycean algae themselves but by other algae attached to them; and (3) Chl e may be an induced pigment under certain light conditions. As a result, it became smaller the possibility that Chl e is induced by the acclimation to light quality. However, we could not rule out the possibility that Chl e was originated from other algae attached on the xanthophycean algae. On the other hand, the studies on chlorophyllase activity of microalgae has increased the possibility that Chl e is a by-product generated during the pigment extraction.
Academic Significance and Societal Importance of the Research Achievements	本研究期間中にChl eの再発見には至らなかったため，当初期待していたようなインパクトはない。一方で，光質に対する順化によって黄緑藻類の個々の色素の相対的含量や細胞形態・生活環が変化することが明らかになったこと，さらに，微細藻類におけるクロロフィラーゼ活性の有無及びその強弱が，藻類の系統とは関係なく株依存的であり，また，藻類の生育段階や光照射の有無等によって変化しなかったことなど，藻類学の発展に貢献できる新たな知見が得られた。