マグネトタクティックな細菌によって生成された磁石の酸素と鉄の同位素の研究
Mandernack1, Bazylinski, Shanks
1Department of Chemistry and Geochemistry, Colorado School of Mines, Golden, CO 80401, USA. Department of Microbiology, Iowa State University, Ames, IA 50011, USA. U.S. Geological Survey, 973 Denver Federal Center, Denver, CO 80225, USA. Water R.
Science (New York, N.Y.)
|September 18, 1999
まとめ
鉄同位体の分割は,細菌磁石では検出されませんでした. しかし,酸素同位体は温度に依存した分断を示し,古環境研究の新たな洞察を提供した.
科学分野:
- 地質化学 地質化学
- 微生物学 微生物学とは
- バイオミネラライゼーション
背景:
- マグネトタクティックなバクテリアは,細胞内磁石 (Fe3O4) を産生する.
- バイオジェニック・マグネチトのイソトープ分離は完全に理解されていません.
- 既存の分割曲線は,高温モデルや理論モデルに基づいています.
研究 の 目的:
- 細胞内マグネタイトバイオミネラライゼーション中の酸素と鉄の同位体の分断を調査する.
- 細菌磁石の分断を細胞外モデルと理論モデルと比較する.
- バクテリア磁石のための新しい酸素同位素分割曲線を確立する.
主な方法:
- マグネトタクティックな細菌の2種の実験室での研究.
- 制御された温度 (4〜35°C) と酸素条件 (マイクロエアロビック,無酸素).
- 生物学的磁石における酸素と鉄の同位体の分析.
主要な成果:
- バクテリアの磁石に検出可能な鉄同位素分離はありません.
- 磁石における酸素同位体の分割は温度に依存しています.
- 観測された酸素分離は,細胞外熱性細菌磁石の生産と一致しています.
結論:
- バクテリア磁石の酸素同位体の分割は温度に依存しています.
- この発見は,既存の高温/理論的な分割曲線とは対照的です.
- 細菌磁石の酸素-18同位体値は,古気温と形成水の同位体値を含む,古環境再構築を支援することができます.
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