单细胞稳定同位素标记技术在固氮微生物中的应用研究

生物固氮是指固氮微生物将大气中氮气还原为生物可利用氨的过程,是环境中新氮的主要来源,调控初级生产力并影响氮储库的收支平衡。由于环境中大部分固氮微生物不可纯培养,不依赖培养且具有高空间分辨率水平的单细胞技术,成为研究固氮微生物的有力手段。~(15)N_2稳定同位素标记技术,以微生物对~(15)N的同化量或速率为依据,是表征微生物固氮活性的最直接手段。本文对~(15)N_2稳定同位素标记结合两种单细胞技术,即纳米二次离子质谱(Nano SIMS)和单细胞拉曼光谱,用于固氮微生物研究的最新进展进行了综述,内容包括揭示环境中高活性固氮微生物、空间分布、与其他生物的共生关系、细胞生理状态等,并进一步对近期发展的基于单细胞拉曼光谱的固氮微生物研究进行了展望。

Application of single-cell stable isotope probing approach to investigate N2-fixing microorganisms

The total number of marine microorganisms is estimated to be 10³⁰. They are the key components driving marine energy and material recycling and maintaining ecological balance. Research advances in marine microbial diversity contribute to our understanding of the operative mechanisms of marine ecosystems. These knowledges can guide our respondence to ecological crisis of global oceans and our exploration of marine microbial resources. As the number of culturable marine microorganisms is currently low, our knowledges to the abundance, physiological characteristics and ecological functions of marine microbial communities are greatly limited. Ribosomal RNA sequencing technologies can rapidly and accurately identify or classify microorganisms based on nucleic acid sequences at low-cost. These technologies have been used in studying community structure and evolutionary and ecological relationships between microorganisms. In recent years, with the benefit of rapid development in sequencing technologies, marine microbial studies based ribosomal RNA sequencing analyses have achieved remarkable progresses in discovering novel marine microbial lineages, revealing ecological mechanisms and evolutionary relationships between marine microorganisms, discovering novel metabolites and applying in marine bioremediation. In this review, we introduce the technical principles of ribosomal RNA sequencing, the application of three generations of sequencing technologies in studying marine microbial diversity, and variable combinations of library construction and sequencing technologies. Finally, we address prospectives in utilizing these sequencing strategies in studies with different purposes.