金藻昆布糖是硅藻细胞合成的一类葡萄糖多聚物，具有抗炎、抗氧化和抗肿瘤等生物活性功能。氮丰度显著影响金藻昆布糖的合成，但其过程和机制尙不清楚。本项目拟采用多尺度研究策略，对金色奥杜藻和三角褐指藻中金藻昆布糖合成的氮丰度调控模式及作用机制进行对比研究。宏观尺度下，对比不同氮丰度下两株硅藻生长、金藻昆布糖含量及产率的变化，明确氮丰度转换对金藻昆布糖合成的调控模式；介观尺度下，通过XE-PAM和FTIR光谱表征细胞叶绿素荧光参数和生物大分子表面官能团的变化，探索氮丰度转换下细胞光合生理及碳流分配规律，揭示氮丰度调控金藻昆布糖合成的细胞机制；微观尺度下，通过酶标仪和QRT-PCR同步表征金藻昆布糖合成中的关键酶——UGPase酶活性及基因表达变化，结合T载体克隆的同源性分析，揭示氮丰度调控金藻昆布糖合成的分子机制。研究结果为开发利用硅藻金藻昆布糖新资源，采取氮丰度调控金藻昆布糖合成积累提供理论指导。

Chrysolaminarin are a group of glucan accumulating in diatoms, which shows potentials in treating diseases like cancer, infection, and inflammation. Nitrogen abundance has an obvious influence on chrysolaminarin synthesis, yet the process and mechanism is not clear. Nitrogen abundance conversion regulation and its action mechanism in chrysolaminarin synthesis in Odontella aurita and Phaeodactylum tricornutum would be studied by means of multiscale research strategy. At macroscopic scale, impact of nitrogen abundance on diatom growth as well as the content and productivity of chrysolaminarin would be studied. Hence, the regulation mode of nitrogen abundance conversion in chrysolaminarin synthesis would be clarified. At mesoscopic scale, chlorophyll fluorescence parameters and biomacromolecules surface functional group changes would be respectively determined by XE-PAM and FTIR. Cellular photosynthesis physiology and carbon partitioning change rule would be illustrated, and the cellular mechanism of chrysolaminarin synthesis under nitrogen abundance regulation would be elucidated. At microscopic scale, activity of the key enzyme in chrysolaminarin synthesis (UGPase) would be represented by a microplate reader, and the gene expression of UGP would be obtained by use of QRT-PCR. The cellular mechanism of nitrogen abundance regulation in chrysolaminarin synthesis would be elucidated combining homologous analysis of UGP cloning. Theoretical basis for the development of chrysolaminarin from diatoms and the adoption of nitrogen abundance regulation in chrysolaminarin synthesis would be provided with the research results.