| Electron Tomography to Study the Three-dimensional Structure of Plasmodesmata in Plant Tissues–from High Pressure Freezing Preparation to Ultrathin Section Collection
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Author:
Date:
2018-01-05
[Abstract] Plasmodesmata (PD) are nanometric (~20 nm wide) membrane lined pores encased in the cell walls of the adjacent plant cells. They allow the cells to exchange all types of molecules ranging from nutrients like sugar, hormones, to RNAs and various proteins. Unfortunately, they are also hijacked by phyto-viruses, enabling them to spread from cell-to-cell and then systematically throughout the whole plant. Their central position in plant biology makes it crucial to understand their physiology and especially link their function to their structure. Over the past 50 years, electron microscopists have observed them and attempted to ultrastructurally characterize them. They laid the foundation of what is known about these pores (Tilney et al., 1991; Ding et al., 1992; Oparka and ...
[摘要] Plasmodesmata（PD）是包裹在相邻植物细胞的细胞壁中的纳米（〜20nm宽）膜衬里的孔。它们允许细胞交换从糖，激素，RNA到各种蛋白质等营养物质的所有类型的分子。不幸的是，它们也被植物病毒劫持，使它们从细胞间传播，然后在整个植物体系中传播。它们在植物生物学中的核心地位使得理解其生理机制，尤其是将其功能与其结构联系起来至关重要。在过去的50年中，电子显微镜观察家们已经观察到了这些现象，并试图用超微结构来表征它们。他们为已知的这些毛孔奠定了基础（Tilney等人，1991; Ding等人，1992; Oparka和Roberts，2001; Nicolas等人， et al。，2017a）。
尽管三维电子显微镜（3D-EM）爆炸，PD超微结构仍然不支持这种技术。第一个技术难点是在尽可能接近原生状态的情况下处理它们。其次，由于染色/固定试剂穿透率差，其体积增大，含水量高以及存在酸性液泡，植物样品显示自己难以加工。最重要的是，它们在细胞壁上的独特位置和它们的纳米尺寸使得难以方便地染色以便看到这些孔隙的内部运作。
这里我们详细描述Nicolas et al。（2017b）中使用的协议，对PD进行细节化处理，并生成高分辨率的X线断层图。
【背景】高压冻结（HPF）依赖于样品中存在的水的玻璃化。通过以足够高的冷冻速度（10 ...
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| Transmission Electron Microscopy of Centrioles, Basal Bodies and Flagella in Motile Male Gametes of Land Plants
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Author:
Date:
2017-10-05
[Abstract] Motile male gametes (spermatozoids) of land plants are coiled and contain a modified and precisely organized complement of organelles that includes a locomotory apparatus with two to thousands of flagella. Each flagellum is generated from a basal body that originates de novo as a centriole in spermatogenous cell lineages. Much of what is known about the diversity of plant male gametes was derived from detailed transmission electron microscopic studies. Because the process of spermatogenesis results in complete transformation of the shape and organization of these cells, TEM studies have yielded a wealth of information on cellular differentiation. Because green algal progenitor groups contain centrioles and a variety of motile cells, land plant spermatozoids also provide a ...
[摘要] 土地植物的运动雄性配子（精子）卷曲，并含有修改和精确组织的细胞器的补体，其包括具有两至数千个鞭毛的运动器官。每个鞭毛都是从起源于新生细胞的基底体产生的，作为精子细胞谱系中的中心粒。关于植物雄性配子多样性的许多知识来自详细的透射电子显微镜研究。由于精子发生过程导致这些细胞的形状和组织的完全转化，TEM研究已经产生了关于细胞分化的大量信息。由于绿藻藻类祖细胞含有中心粒和各种运动细胞，所以土地植物精子也提供了大量的机会来检验土地殖民时期的中心粒和运动器具的演化和最终的损失。
在这里，我们简要概述了我们在过去20年进行的研究和方法，不仅阐明了这些细胞的结构多样性，而且阐明了微管组织中心的发展。 >中心粒的起源和结构复杂的运动细胞的个体发育。
【背景】土地植物的运动配子是非常多样化的，通过涉及重新定位和重塑细胞组分以及组装复杂运动器官的变革来发展（Renzaglia和Garbary，2001; Lopez和Renzaglia，2008）。由于细胞壁施加的限制，细胞和鞭毛的伸长在几乎球形的空间周围，导致成熟配子的盘绕构型（Renzaglia和Garbary，2001; Lopez和Renzaglia，2014）。卷取程度从每个单元只有一到多到十转。每个配子的鞭毛数量甚至更为可变，从苔藓植物（苔藓植物， ...
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| Preparation of Outer Membrane Vesicles from Myxococcus xanthus
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Author:
Date:
2016-01-20
[Abstract] Outer membrane vesicles (OMVs) represent a unique sub-cellular compartment of bacteria that may act as a scaffold for various extracellular activities, including intercellular signaling. Myxococcus xanthus (M. xanthus) is a predatory bacterium that engages in cell-cell behaviors such as fruiting body formation and contact dependent lysis of other microbes. The OMVs of M. xanthus have been shown to have an elaborate architecture of chains and tubes that can connect cells within a biofilm. These higher order OMV structures have been shown to contain proteins exchanged for community behaviors and small molecules that have antibiotic activities, and may help facilitate directed exchange. M. xanthus OMVs allow material transfer between neighboring cells for ...
[摘要] 外膜囊泡（OMV）代表细菌的独特亚细胞区室，其可以充当各种细胞外活性（包括细胞间信号传导）的支架。 （Myxococcus xanthus）是一种掠夺性细菌，其参与细胞 - 细胞行为，例如子实体形成和其他微生物的接触依赖性裂解。 M.M的OMV。 xanthus已经显示具有可以连接生物膜内的细胞的链和管的精细结构。 这些更高级的OMV结构已经显示含有交换为社区行为的蛋白质和具有抗生素活性的小分子，并且可以有助于促进定向交换。 M。 xanthus OMV允许相邻细胞之间的物质转移，用于运动和捕食。
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