Nitrate assimilation by marine heterotrophic bacteria

Nitrate assimilation is a process where bacteria utilize nitrate as a nitrogen source and synthesize it into organic nitrogen. We found that nitrate-assimilating bacteria(NAB) are widely distributed in various marine environments, from surface to the deep ocean and sediment, which indicates that NAB are significant to the oceanic nitrogen cycle. Comparative genomic analysis revealed nitrate-assimilating genes(nas A) in these marine heterotrophic NAB showed different gene arrangements and diverse regulation systems. Summary on recent findings will contribute to understanding the process of nitrate assimilation in NAB and their ecological significance in the nitrogen cycle. A systematic analysis of a number of studies on bacterial nitrate assimilation in marine ecological systems was conducted to clarify directions for future research.

海洋厌氧氨氧化细菌分子生态学研究进展

厌氧氨氧化细菌是能在厌氧的条件下将氨氧化为氮气的一类细菌，这类细菌执行着以前未被人们所认知的一个独特的过程——厌氧氨氧化过程，据估计厌氧氨氧化过程对于海洋氮气的形成有30％～50％的贡献率；海洋厌氧氨氧化细菌能与氨氧化细菌及氨氧化古菌存在潜在的耦合作用，对于海洋氮循环复杂机制的阐述有着非常重要的意义；同时海洋厌氧氨氧化细菌独特的细胞和基因组结构，也成为了解海洋细菌进化重要的模式微生物之一。本文综述了近年来国内外厌氧氨氧化细菌分子生态学方面的进展，并结合作者的工作对未来的研究进行展望。