一种热液喷口古菌在92摄氏度下的固氮作用。

Nitrogen fixation at 92 degrees C by a hydrothermal vent archaeon.

作者信息

Mehta Mausmi P, Baross John A

机构信息

School of Oceanography, University of Washington, Seattle, WA 98195, USA.

出版信息

Science. 2006 Dec 15;314(5806):1783-6. doi: 10.1126/science.1134772.

DOI:10.1126/science.1134772

PMID:17170307

Abstract

A methanogenic archaeon isolated from deep-sea hydrothermal vent fluid was found to reduce N(2) to NH(3) at up to 92 degrees C, which is 28 degrees C higher than the current upper temperature limit of biological nitrogen fixation. The 16S ribosomal RNA gene of the hyperthermophilic nitrogen fixer, designated FS406-22, was 99% similar to that of non-nitrogen fixing Methanocaldococcus jannaschii DSM 2661. At its optimal growth temperature of 90 degrees C, FS406-22 incorporated (15)N(2) and expressed nifH messenger RNA. This increase in the temperature limit of nitrogen fixation could reveal a broader range of conditions for life in the subseafloor biosphere and other nitrogen-limited ecosystems than previously estimated.

摘要

从深海热液喷口流体中分离出的一种产甲烷古菌被发现能在高达92摄氏度的温度下将N₂还原为NH₃，这比目前生物固氮的温度上限高28摄氏度。这种嗜热固氮菌（命名为FS406-22）的16S核糖体RNA基因与非固氮的詹氏甲烷球菌DSM 2661的该基因相似度达99%。在其90摄氏度的最佳生长温度下，FS406-22能结合¹⁵N₂并表达nifH信使RNA。固氮温度上限的这一提高可能揭示了海底生物圈和其他氮限制生态系统中比先前估计更广泛的生命存在条件。