光合成ダイアトムの尿素循環の進化と代謝の重要性
Andrew E Allen1, Christopher L Dupont, Miroslav Oborník
1J. Craig Venter Institute, San Diego, California 92121, USA. aallen@jcvi.org
Nature
|May 13, 2011
まとめ
ダイアトムは,窒素の制限から迅速に回復するために,エクソシンビオント派生のオルニチン-尿素サイクルを使用します. この経路は,海洋の生産性にとって極めて重要であり,重要な代謝機能のための細菌とエクソシンビオントの遺伝子を結びつける.
科学分野:
- マリン・バイオロジーの海洋生物学
- 分子生物学は分子生物学である.
- バイオケミストリー バイオケミストリー
背景:
- ダイアトムは,生産的な海洋食物網における重要な植物プランクトンである.
- 彼らのゲノムには,バクテリア,プラスティド,および二次エンドシンビオティック宿主 (エクソシンビオン) の遺伝子が含まれています.
- これらの遺伝子群がダイアトムに与える代謝的貢献は,依然としてほとんど不明である.
研究 の 目的:
- ダイアトムの代謝におけるエクソシンビオント派生オルニチン-尿素循環の役割を調査する.
- 窒素の利用と回収への貢献を決定する.
- エキソシンビオント,バクテリア,宿主由来経路の間の代謝関連性を探求する.
主な方法:
- ミトコンドリアカルバモイルリン酸合成酵素をノックダウンするRNA干渉 (RNAi).
- メタボロミック分析により,代謝物質のレベルを評価する.
- 遺伝子の起源を理解するための比較ゲノミクス.
主要な成果:
- カーバモイルリン酸塩合成酵素のノックダウンにより,窒素制限ダイアトムの窒素添加に対する反応が低下した.
- オルニチン-尿素サイクルの中間物質は枯渇し,トリカルボキシル酸とグルタミン合成酵素/グルタミン酸合成酵素サイクルと結合した.
- プロリンおよびポリアミン前駆体を含む代謝物は,結合された細菌とエクソシンビオント経路を通じて生成されました.
結論:
- 藻のオルニチン-尿素の循環は,窒素の制限から急速な回復を促進します.
- ダイアトムの成長に不可欠な無機炭素と窒素の分布のハブとして機能します.
- この循環は,海洋生産性へのダイアトムの貢献と,変動する栄養素の利用可能性への適応に不可欠です.
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