海洋氮循环过程及基于基因组代谢网络模型的预测

Marine nitrogen cycle and prediction based on genome-scale metabolic network model

摘要:

海洋氮循环在地球元素循环中充当着必不可少的角色。海洋氮循环是由一系列氧化还原反应构成的生物化学过程。固氮作用和氮同化作用为生态系统提供了生物可用氮（铵盐）。硝化作用可进一步将铵盐氧化为硝酸盐，硝酸盐又可以通过反硝化作用转化为氮气。整个氮循环实现了海洋中不同含氮无机盐间的转换。微生物是海洋氮循环的重要驱动者，海洋氮循环的研究可以帮助理解海洋生物与地球环境相互作用及协同演化的机制，从而更好地保护地球生态环境。随着氮循环关键微生物基因组尺度代谢网络模型的发表，研究者可以利用代谢网络模型来研究不同氮循环过程的效率、环境因子对氮循环过程的影响以及解析氮循环及生物网络的内在机理等，从而帮助人们更深入地研究海洋氮转化机制。本文主要综述了海洋氮循环过程中各个转化过程的主要微生物，以及基因组尺度代谢网络模型在分析氮循环中的应用。

关键词:固氮过程;硝化过程;反硝化过程;厌氧氨氧化过程;异化硝酸/亚硝酸还原过程;海洋氮循环

Abstract:

The marine nitrogen cycling is one major component in Earth’s element cycle. The marine nitrogen cycling is a biochemical process composed of a series of redox reactions. Nitrogen fixation and nitrogen assimilation supplies critical bioavailable nitrogen (ammonium) to ecosystems. Nitrification can further convert ammonium into nitrates, while denitrification can convert nitrate into nitrogen. Different nitrogen forms are converted through the nitrogen cycle in the ocean. Studying marine nitrogen cycling could help understand the mechanism of interaction and co-evolution between marine organisms and Earth environment. It may also better protect the Earth’s ecological environment. By employing the published genome-scale metabolic network models based on key microorganisms involved in nitrogen cycling, researchers can study the efficiency of different nitrogen cycle processes and their influencing environmental factors, and disclose the mechanism of the nitrogen cycle and biological network, so as to help further study the mechanism of marine nitrogen conversion. This article mainly reviews the main microorganisms involved in each transformation process in the marine nitrogen cycle and applications of genome-scale metabolic network models in the analysis of the nitrogen cycle.

Key words:nitrogen fixation;nitrification;denitrification;anaerobic ammonia oxidation;dissimilatory nitrate reduction to ammonium;marine nitrogen cycle