^13C稳定同位素示踪技术在小硅藻光合膜脂合成途径中的应用  

Investigation of Synthetic Pathway of Photosynthetic Membrane Lipids in Nitzschiaclosterium f. Minutissima Based on ^13C Stable-Isotope-Tracer Technique

作　　者：李双[1,2] 洪梦蓉 王春芳 陈树兵 徐继林 陈娟娟[1] LI Shuang;HONG Meng-Rong;WANG Chun-Fang;CHEN Shu-Bing;XU Ji-Lin;CHEN Juan-Juan(State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products,Ningbo University,Ningbo 315211;Ningbo Customs Technology Center,Ningbo 315040,China)

机构地区：[1]宁波大学农产品质量安全危害因子与风险防控国家重点实验室,宁波315211 [2]宁波海关技术中心,宁波315040

出　　处：《分析化学》2020年第6期786-793,共8页Chinese Journal of Analytical Chemistry

基　　金：国家重点研发计划项目(No.2018YFD0901103);宁波大学王宽诚基金(K.C.Wong Magna);浙江省基础公益研究计划项目(No.LGN18B050002)资助。

摘　　要：采用13C稳定同位素示踪技术结合高分辨质谱方法,研究了小硅藻中4类光合膜脂(二酰甘油单半乳糖脂(MGDG)、二酰甘油双半乳糖脂(DGDG)、二酰甘油硫代糖脂(SQDG)和磷脂酰甘油(PG))的合成途径。与通过物质含量的变化进行合成与代谢途径研究的传统方法相比,本方法更直观、准确地阐明了小硅藻光合膜脂中碳原子的去向。研究结果表明,小硅藻中4类光合膜脂均被标记,且标记含量在小硅藻生长周期的整个平台期逐渐增加。对二级质谱碎裂片段分析结果表明,光合膜脂的空间结构在13C标记方面起着决定性作用,即4类光合膜脂的极性头部被优先标记,其次是甘油骨架,最后是两条脂肪酸酰基链,且两条脂酰链的位置差别影响不大,几乎是同步合成。本方法可以直观准确地阐明小硅藻中光合膜脂对碳原子的利用途径,为相关研究提供了参考。Isotope labeling in conjunction with high resolution mass spectrometry(HRMS) was used for investigation of transformation pathway in photosynthetic membrane lipids in Nitzschiaclosterium f. minutissima: diacylglycerol monogalactose(MGDG), diacylglycerol digalactose(DGDG), diacylglycerol thioglyceride(SQDG) and phosphatidylglycerol(PG), and had been demonstrated as a perfect superior tool to directly illuminate the transfer pathway of carbon in photosynthetic glycerolipids, which in contrast to previous studies where only changes in compositions were taken as evidence for these processes. The experimental results showed that 4 photosynthetic membrane lipids were labeled, and the labeling content increased gradually during the whole platform. Besides, spatial structure played a decisive role in labeling priority and provided insight into photosynthetic glycolipids synthesis in marine diatoms based on MS/MS, including suggestion of an preferably labeled of backbone-linked headgroups, and then was the glycerol skeleton and fatty acid substituents. It was also observed that 13C incorporated into those headgroups almost simultaneously. The method could directly and accurately illuminate the utilization of carbon atoms by photosynthetic glycerolipids in Nitzschiaclosterium f. minutissima. It provided a reference analysis platform for exploring the assimilation process of microalgae lipid biomarkers in the future by Sinonovaculaconstricta.

关 键 词：^13C稳定同位素示踪 小硅藻 光合膜脂 四极杆/静电场轨道阱高分辨质谱 

分 类 号：O657.63[理学—分析化学] S917.3[理学—化学]