ミネラル表面の細菌認識:シェワネラ菌とアルファ-FeOOH間のナノスケール相互作用
S K Lower1, M F Hochella, T J Beveridge
1NanoGeoscience and Technology Laboratory, Department of Geological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA. slower@vt.edu
Science (New York, N.Y.)
|May 19, 2001
まとめ
Shewanella oneidensisバクテリアは,無酸素条件下でゴエチット鉱物に対する親和性が高まっていることを示しています. 推定鉄還元酵素によって促進されるこの相互作用は,表面に近い環境における微生物の金属還元に極めて重要です.
科学分野:
- 微生物学 微生物学とは
- 地質化学 地質化学
- バイオフィジックス 生物物理学
背景:
- シェワネッラ・オネイドンシス (Shewanella oneidensis) は,非類似性のある金属を減少させる細菌である.
- ゴエチート (alpha-FeOOH) は,地球の表面に近い環境にある一般的な鉄酸化水酸化鉱物です.
- 細菌と鉱物の相互作用を理解することは,生地化学の循環の鍵です.
研究 の 目的:
- S. oneidensis と goethite. の間の力を定量的に測定する.
- 細胞と鉱物の相互作用に対する環境条件 (有酸素と無酸素) の影響を調査する.
- 電子移転を促進する分子機構を特定する.
主な方法:
- 力の顕微鏡を用いて,生きているS.oneidensisの細胞とゴエチットの間の無限微小の力を測定した.
- 異なる距離と溶液条件 (有酸素/無酸素) でリアルタイムで測定を行った.
- 力の曲線を分析してエネルギー値を導き,相互作用のサインを特定した.
主要な成果:
- アネロビック条件下では,S.oneidensis-goethite afinityの2〜5倍の増加が観察されました.
- 増加した親和性が,予想される無酸素電子伝送と相関することを実証した.
- 150kDaの推定鉄還元酵素の動員を示唆する特定の力曲線シグネチャーを特定しました.
結論:
- アナエロビック状態は,S. oneidensisとgoethite. の間の結合親和性を著しく高めます.
- バクテリアの外膜に存在する鉄還元酵素が,ゲチートへの電子の移転を促進する役割を果たしている.
- これらの発見は,微生物の金属還元プロセスに対する分子洞察を提供します.
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