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完全な窒素化器の運動分析は,オリゴトロフなライフスタイルを明らかにする

K Dimitri Kits¹, Christopher J Sedlacek¹, Elena V Lebedeva²

¹Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network Chemistry meets Microbiology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.

|August 29, 2017

まとめ

ニトロスピラ・イノピナタのような完全なアンモニア酸化剤 (コマモックス) は,オリゴトロフ環境で繁栄する. その高いアンモニアの親和性は,アンモニア酸化アーカイア (AOA) についての以前の仮定に異議を唱える,窒素化における重要な役割を果たすことを示唆している.

科学分野:

微生物学
環境科学
生地化学

背景:

窒素化は窒素循環の重要なステップであり,伝統的にアンモニア酸化細菌 (AOB),古生物 (AOA) と窒素酸化細菌 (NOB) を分離する.
ニトロスピラ属内でアンモニアを窒素に変換できる完全なアンモニア酸化剤 (コマモックス) の発見は,それらの生態学的役割と競争上の優位性を理解することが必要である.

研究の目的:

コマモックス・ニトロスピラ・イノピナタの生態学的ニッチと競争力を調査する.
コマモックス・ニトロスピラとアンモニア酸化アーカイア (AOA) の窒素化運動と基板親和を比較する.

主な方法:

ニトロスピラ・イノピナタの純粋な培養物の分離と特徴付け
N. inopinataと4つの土壌/温泉AOA単離物に対する基板親和と成長率を含む窒化運動の決定.
代謝の可能性を評価するゲノム分析

主要な成果:

ニトロスピラ・イノピナタは,高濃度のアンモニアと低い最大酸化率を特徴とする,オリゴトロフおよびダイナミックな生息地での遅い成長に適応している.
N. inopinataは,正規の窒素化剤と比較して,より高い成長率を示しています.
研究されたAOA単離物は,驚くほど低い基板親和性と低い成長率を示し,オリゴトロフ環境で最も競争力のあるアンモニア酸化物質ではないことを示した.
N. inopinataは,海洋AOA Nitrosopumilus maritimus SCM1を除いて,分析された単離物の中で最も高い基板親和性を有する.

結論:

コマモックス生物,特にニトロスピラ・イノピナタは,オリゴトロフおよびダイナミックな環境で窒素化に適しています.
これらの発見は,オリゴトロフィック条件におけるAOAの支配的地位に関する長年の見解に異議を唱え,これらのニッチにおけるコマモックスの競争力を強調しています.

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