オープンオーシャンで窒素を固定するサイアノバクテリアにおける代謝の効率化
H James Tripp1, Shellie R Bench, Kendra A Turk
1Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA.
Nature
|February 23, 2010
まとめ
海洋サイアノバクテリアUCYN-Aは酸素 fotosynthesisを欠いて,ユニークな光発酵代謝を利用しています. この窒素を固定する生物は,必要不可欠な栄養素を他者に依存し,海洋における微生物の相互依存を強調しています.
科学分野:
- マリン・マイクロバイオロジー
- バイオジオケミストリー バイオジオケミストリー
- ゲノミクスゲノミクスとは
背景:
- 窒素 (N2) を固定する海洋サイアノバクテリアは,海洋の一次生産性と大気中の二酸化炭素除去に不可欠です.
- 世界的に分布するUCYN-Aサイアノバクテリアには光システムIIがなく,新しい代謝が示唆されているが,培養されていないままである.
研究 の 目的:
- 培養されていないUCYN-Aサイアノバクテリアの代謝能力と栄養依存度を明らかにする.
- 海洋生態系におけるUCYN-Aの進化的適応と生態学的役割を理解する.
主な方法:
- 大規模なパラレルピロシーケンシングを用いたUCYN-A全ゲノムのアセンブリ.
- ゲノムデータに基づく代謝再構築.
- UCYN-Aの減少したゲノム構造と遺伝子含有量の分析.
主要な成果:
- UCYN-Aは光発酵代謝をしており,光からエネルギーを生成し,光からエネルギーを削減します.
- 生物体には,トリカルボキシル酸循環や,アミノ酸とピュリンの必要不可欠な生物合成経路のような主要な代謝経路が欠けている.
- UCYN-Aは縮小されたゲノム (1.44 Mb) を表しており,クロロプラストや細菌と構造的に類似しており,逆転したrRNAオペロンを含む.
結論:
- UCYN-Aは,おそらく密接な関連または共生を通じて,重要な栄養素の代謝的に他の生物に依存しています.
- 研究結果は,UCYN-Aが微生物の進化と適応におけるパラドックスであり,オリゴトロフィック環境における密接な代謝結合を示しています.
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