寡营养淡水环境中氨氧化古菌及其氨氧化特性研究

Recently, ammonia-oxidizing archaea (AOA)was found as a main member of microbes in ammonia oxidation, and the number of it is higher than ammonia-oxidizing bacteria (AOB)in kinds of environments. In natural ecosystem, the microbial ecology of community distribution, abundance and evolution, ammonia oxidation, biochemical and biophysical characteristics, and genome bioinformation of AOA in freshwater still need more and precisely research.In this project, we will study the distribution of AOA/AOB in vertical and horizontal districts of oligotrophic freshwater to analyze the evolution of AOA/AOB, the response of AOA/AOB community stability and change to physical and chemical factors. Microbial ecology of AOA/AOB in oligotrophic freshwater will be revealed by the research of their distribution, abundance, community structure, and diversity. Stable isotope probing (SIP) will be used to labelled the nucleotide of N-element transformation microbes, and the ammonia-oxidizing ability of AOA/AOB in freshwater will be studied based on the SIP labelled DNA and RNA. After the analysis, the contribution of ammonia oxidation by AOA and AOB will be figured out clearly. Basing on the microbial ecology research, we will design special enrichment method to obtain freshwater type AOA stains. After isolating the AOA strans, we will characterize their biochemistry and biophysics including the response to dissolve oxygen and ammonia concentration, ammonia oxidation, even denitrifiaction kinetics and so on.AOA genome sequence will be obtained by high throughput and metagenomic sequencing techniques. Basing on the genome sequence, genome bioinformation of AOA including gene structure, ammonia oxidation enzyme system, metabiotic pathway, and energy regulation will be analyzed. In the meantime, the genome and functional genes of freshwater type AOA will be compared with the sequences of the known AOA in databases. This project will be helpful for the revelation of ammonia oxidation in freshwater, and the expansion of ecology, biochemistry and biophysic, and genome bioinformations of AOA in natural environemnt. So, the research project has important theory and application values for bioremediation of ammonium polluted environments.

近期研究发现氨氧化古菌(AOA)也是自然界中氨氧化作用的主要贡献者，且在很多环境中数量高于氨氧化细菌(AOB)，但它们在环境中的群落、丰度、进化等生态学信息、氨氧化特性、基因组生物信息仍较少。本项目以寡营养淡水环境为对象，深入研究其中AOA/AOB的垂直和水平分布、AOA/AOB的物种进化和群落结构对理化因子的响应，揭示它们在环境中的分子生态学；利用SIP核苷酸标记，研究环境中AOA/AOB的氨氧化活性，分析它们对氨氧化作用的贡献率；通过对淡水型AOA富集，分离到纯化的菌株，研究AOA氨氧化动力学、呼吸作用、反硝化等理化特性；通过高通量和宏基因组测序技术获得AOA的基因组序列，研究淡水型AOA的基因结构、氨氧化酶系、能量及代谢调控等生物信息，并与已知AOA进行比较。本课题的完成将有助于揭示淡水环境中氨氧化作用和拓展AOA的生态、理化和基因组信息，对环境生物修复具有重要的理论意义和应用价值。