STRUCTURE OF PLASMODESMATA (INTERCELLULAR PLANT JUNCTIONS)

我们正在研究植物细胞间的三维结构 胞间连丝(PD)。奇沃茨基博士的实验室送来了 Sosinsky博士包含从以下位置剪切的厚层和薄层网格 嵌入和剖切的材料。这些样本是1)叶组织2) 胞间连丝(PD)纯化的细胞壁和3)纯化的细胞壁 用洗涤剂CHAPS治疗帕金森病。索辛斯基博士收集了 3倾斜系列样品2.第一次重建刚刚包含 细胞壁，所以索辛斯基博士将收集更多的倾斜系列。她是 目前正在检测叶片组织中的PD，以与分离的 生化特征的PD。在过去的一年里，我们已经获得了 从含有以下物质的纯化细胞壁制备的五个倾斜系列 胞间连丝蛋白。《倾斜》系列中有三个出自Chaps(a 洗涤剂)处理细胞壁，而另外两个倾斜系列 来自未经洗涤剂处理的制剂。每一个人的断层照片 对5个倾斜度序列进行了计算。令人惊讶的是， 所有五张断层照片中的胞间连丝看起来都不像是基于 投影图像。在基于两者的薄层图像的模型中 分离的胞间连丝和叶组织中发现的胞间连丝， 胞间连丝应该类似于类似于 核孔复合体。在断层图像中，我们发现了两个椭圆体 纵向跨越细胞壁的细长结构，但不是 径向的。我们将从完整的叶子组织中录制倾斜系列 因此从这些倾斜序列按顺序计算层析图像 为了评估胞间连丝结构是否为桶形，以及 结构中蛋白质的大量损失在 隔离(与项目的生物化学相协调)或 基于薄层的模型是不正确的，确实， 胞间连丝结构不是实心圆柱体。

We are studying the 3-dimensional structure of plant intercellular connections, the plasmodesmata (PD). Dr. Civotsky's laboratory sent Dr. Sosinsky grids containing thick and thin sections cut from embedded and sectioned material. These samples are 1) leaf tissue 2) purfied cell walls with plasmodesmata (PD) and 3) purified cell walls with PD treated with the detergent chaps. Dr. Sosinsky has collected 3 tilt series of sample 2. The first reconstruction just contained cell walls, so Dr. Sosinsky will collect more tilt series. She is presently examining the PD's in leaf tissue to compare with isolated, biochemically characterized PD's. In the past year, we have acquired five tilt series from preparations of purified cell walls containing plasmodesmota proteins. Three of the tilt series were from CHAPS (a detergent) treated cell walls while the other two tilt series were from preparations which were not detergent treated. Tomograms of each of the five tilt series were computed. Surprisingly, the plasmodesmota in all five tomograms did not look like models based on projection images. In models based on thin section images from both isolated plasmodesmota and ones found in leaf tissue, the plasmodesmota should resemble a barrel-shaped structure analogous to nuclear pore complexes. In the tomograpms, we found two elipsoidal elongated structures that span the cell wall longitudinally, but not radially. We will be recording tilt series from intact leaf tissue and consequently computing tomograms from these tilt series in order to assess if the plasmodesmota structure is barrel-shaped and a significant loss of pro teins in the structure have been lost during isolation (coordinating with the biochemistry of the project) or that the model based on thin section is incorrect and indeed, the plasmodesmota structure is not a solid cylinder.