マンガンの光による無酸素微生物酸化

Mirna Daye¹, Vanja Klepac-Ceraj², Mihkel Pajusalu³

¹Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA. mirnadaye@gmail.com.

Nature

|December 6, 2019

まとめ

無酸素の光合成微生物は酸素なしでマンガン酸化物を生成し,初期の光合成に関する以前の仮定に異議を唱えます. この発見は初期の地球を示唆しています

科学分野:

地化学
微生物学
古生物学

背景:

酸素による光合成は地球の生物圏にとって極めて重要ですがその起源についてはまだ議論が続いています
マンガン酸化物の証拠に基づいて,約30億年前に酸素光合成の進化を示唆した.
これらの仮定は,酸素または特定の光合成センターの存在でしか形成されないマンガンの酸化物に基づいていた.

研究の目的:

微生物によるマンガンの酸化物の生物鉱化を無毒条件下で調査する.
初期の光合成代謝と関連する地化学信号の起源を再評価する.

主な方法:

マンガンの酸化物を生物鉱化できる微生物群を調査した.
厳格な無酸素状態で実験を行った.
微生物によるマンガンの酸化によって生成された地化学的サインを分析した.

主要な成果:

無酸素の光合成微生物が分子酸素なしでマンガンの酸化物を生物鉱化することが示された.
微生物によるMn ((II) の酸化は,酸素光合成と区別できない地化学信号を生成することを示した.
この光に依存するプロセスは,現代の無酸素水環境で起こることが確認されました.

結論:

酸素 fotosynthesisの起源は,以前はマンガン酸化物の堆積物から推測されたほど古くはないかもしれません.
無酸素光合成は,大酸化事象以前に同様の地化学信号を生成した可能性があります.
このプロセスは,初期の地球の生地化学サイクルと生命の進化を理解するための意味を持っています.

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