BIOSYNTHESIS OF TRIACYLGLYCEROLS IN DEVELOPING OILSEEDS

在这个项目中，我们使用完整植物的稳定同位素标记 分析脂肪酸和脂肪生物合成途径的组织 从[13C]或[13C，18O]醋酸酯、[18O]水和[13C，18O]醋酸酯等前体 [13C]二氧化碳。这些实验为我们提供了有关 前驱体池、通过前驱体池的通量以及 脂类生物合成中可能的水解性反应。已经， 叶子的初步数据表明，散装醋酸池并不是 脂肪酸合成的主要碳源和长链 叶绿体的脂肪酰基输出确实是通过水解物发生的。 机制。我们已经用MS检查了它的同位素组成 新天然产物的前体和鉴定)。更多 重要的是，我们已经确定了几个质谱学实验 这将帮助我们解开数字的根本问题 脂肪酸和脂肪合成系统在人的细胞中运行 开发油料种子。这些实验将需要开发 质谱学方法，特别是(1)测量 单个油体中性脂的分子种类，以及(2) 种子组织的超低温切片及其二维分布图 尽可能高分辨率的脂类分子物种 (最好接近单个细胞的分辨率)，使用MALDI-TOF 或其他可聚焦软电离技术。这两种类型的 实验将扩大质谱学的适用范围 研究脂肪的生物合成，需要一个令人兴奋和互动的 与密歇根州立大学的质谱学设施合作。

In this project we use stable isotope labeling of intact plant tissues to analyze the pathways of fatty acid and lipid biosynthesis from precursors such as [13C] or [13C, 18O]acetate, [18O]water and [13C]carbon dioxide. These experiments give us information on the precursor pools, fluxes through precursor pools, and the relevance of putative hydrolytic reactions in lipid biosynthesis. Already, preliminary data for leaves suggests that the bulk acetate pool is not the primary carbon source for fatty acid synthesis and that long-chain fatty acyl export from the plastid does indeed occur via a hydrolytic mechanism. We have used MS to check the isotope composition of precursor and identification of novel natural products). More importantly, we have identified several mass spectrometry experiments which will help us unlock the fundamental question of the number of fatty acid and lipid synthesizing systems operating in the cell of the developing oilseed. These experiments will require development of mass spectrometry methods, and in particular (1) the measurement of molecular species of neutral lipids in INDIVIDUAL oil bodies, and (2) cryo-sectioning of seed tissue and mapping the 2-D distribution of lipid molecular species at as high a resolution as possible (preferably approaching resolution of a single cell), using MALDI-TOF or other focusable soft ionization technique. Both these types of experiment would expand the applicability of mass spectroscopy for the study of lipid biosynthesis and require an exciting and interactive collaboration with the MSU Mass Spectrometry Facility.