Gordon A J, Thomas B J, James C L
Cell Biology Department, Institute of Grassland & Environmental Research, Plas Gogerddan, Aberystwyth, Dyfed SY23 3EB, UK.
New Phytol. 1995 Aug;130(4):523-530. doi: 10.1111/j.1469-8137.1995.tb04329.x.
Immunogold labelling was used to identify the location of the sucrose hydrolytic enzyme sucrose synthase in the N -fixing root nodules of white clover. This is the major enzyme of sucrose cleavage in clover nodules and might be involved in the modulation of N fixation by controlling the rate of utilization of photosynthetic products. Knowledge of the precise cellular location of this enzyme in relation to the point of delivery (the vascular bundles) and the site of utilization of the catabolic product (malate in the bacteroids) might aid our understanding of the metabolic communication between different cell types of the nodule. Gold particle density was greatest in the cytosol of uninfected cells of the central region and in the layer of cortical cells in direct contact with infected cells. By contrast, relative gold particle density was 2-3 fold lower in the cytosol of infected cells. The distribution of sucrose synthase is discussed in relation to sucrose transport, starch metabolism and the provision of carbon and energy for N fixation.
免疫金标记法被用于确定蔗糖水解酶蔗糖合酶在白三叶草固氮根瘤中的位置。这是三叶草根瘤中蔗糖裂解的主要酶，可能通过控制光合产物的利用速率参与固氮调节。了解该酶在精确细胞位置与输送点（维管束）以及分解代谢产物利用部位（类菌体中的苹果酸）之间的关系，可能有助于我们理解根瘤不同细胞类型之间的代谢通讯。在中央区域未感染细胞的胞质溶胶以及与感染细胞直接接触的皮层细胞层中，金颗粒密度最大。相比之下，感染细胞胞质溶胶中的相对金颗粒密度低2至3倍。文中讨论了蔗糖合酶的分布与蔗糖运输、淀粉代谢以及为固氮提供碳和能量的关系。
