北极斯瓦尔巴德群岛近海产蛋白酶适冷细菌资源的系统分类与多样性、所产适冷蛋白酶的多样性及环境适应

The Arctic Ocean is an area with wide continental shelf and many marginal seas. The offshore sediment is greatly influenced by terrestrial input and has highly organic nitrogen content, and therefore it is significant to research the biogeochemical processes and mechanisms of organic nitrogen involved in the microorganisms in Arctic offshore.The offshore water freezes in winter and melts in summer due to the extremely climatic conditions of the Arctic Svalbard islands containing year-round low temperature, polar day in summer and polar night in winter. The severe change of environment makes the Arctic sea an ideal coastal area for studying the biogeochemical processes of organic nitrogen and the environmental responses of the organism. In this study, we will research the diversity of cold-adapted protease-producing bacteria in this aera at different stations and compare it with that of Fildes peninsula offshore in Antarctica and subsequently reveal the biogeography characteristics of the proteases-producing bacteria in Arctic offshore. The phylogenetic taxonomy of the strains which were suspected to be novel species or genus will be investigated to discover novel taxon of novel species or genus, which enrich the resources of the bacterial strains in Arctic. Furthermore,this study would reaveal the cataclytic mechanism, diversity and adapted mechanism of cold-adapted proteases by investigating their cataclytic properties, structures, comparative genomics and transcriptomics aspects. The results would laid a fundation for clarifying the organic nitrogen biogeochemical processes and mechanisms of nitrogen cycle involved in Arctic microorganisms.

北极海域陆架区宽阔，拥有众多的边缘海，受陆源输入影响较大，近海沉积物中有机氮含量较高,揭示微生物参与的北极近海有机氮生物地球化学过程与机制，具有重要理论意义。北极斯瓦尔巴德群岛附近海域终年低温、夏季极昼、冬天极夜，近海冬季海水结冰、夏季海冰融化，环境变化剧烈，是研究北极近海有机氮生物地球化学过程及环境响应的理想区域。本项目拟系统研究该区域近海不同站点产蛋白酶的适冷细菌多样性，与南极菲尔德斯半岛近海进行比较，揭示北极近海产蛋白酶细菌的生物地理学特征。对疑似细菌新种、属菌株进行系统分类学鉴定，建立多个细菌新种、属等新的分类单元，丰富我国北极海域细菌菌种资源。进一步从酶学特性与其催化特性、部分酶蛋白结构、基因组学和比较转录组学等多个层次，揭示北极近海适冷细菌所产蛋白酶的催化机制、隶属蛋白酶家族的多样性及其对北极极端环境的适应特性，为最终阐明北极近海细菌参与的有机氮生物地球化学过程与机制奠定基础。

北冰洋海岸线曲折，类型多，宽阔的陆架区发育出许多浅水边缘海和海湾，受陆源物质影响较大，北极近海，尤其是近海沉积物中有机质含量较高，蕴藏着丰富的细菌物种资源，推动着北极近海各种物质循环尤其是氮循环的进行。但是人们对于参与北极近海有机氮降解的微生物种群及其所分泌酶的了解非常有限。北极斯瓦尔巴德群岛地处高纬度，温度、湿度等环境因子变化剧烈，是研究北极近海有机氮生物地球化学过程及环境响应的理想区域。本项目采集了北极斯瓦尔巴德群岛不同站点近海海水及沉积物样品，从中分离产蛋白酶的适冷细菌，研究该区域产蛋白酶适冷细菌的多样性及随站点的变化规律，与南极长城站菲尔德斯半岛近海产蛋白酶的适冷细菌的多样性进行比较，揭示了北极斯瓦尔巴德群岛近海产蛋白酶细菌的生物地理学特征。对疑似细菌新种、属菌株进行了系统分类学鉴定，建立多个细菌新属、种等新的分类单元，丰富了我国北极海域细菌菌种资源。并从酶学特性与其催化特性、部分酶蛋白的结构、基因组学和比较转录组学等多个层次，揭示了北极近海适冷细菌所产蛋白酶的催化机制、隶属蛋白酶家族的多样性及其对北极极端环境的适应特性，为最终阐明北极近海细菌参与的有机氮生物地球化学过程与机制奠定了基础。