MRI: Acquisition of a High-Resolution Electron Tomography System

配备了用于断层扫描的倾斜样品支架和冷冻工作台的中压(300千伏)电子显微镜长期满足为威斯康星大学麦迪逊分校的各种生物和生物工程研究项目提供关键成像技术的需求。这种显微镜的使用者严重依赖高分辨率成像来进行广泛的重要课题的工作，包括膜和蛋白质运输、生物矿物和生物聚合物、病毒复制和病毒-宿主相互作用、细胞骨架组织和细胞分裂、神经末梢组织和胞吐作用、细菌结构、分子复合体成像和神经工程。这种成像系统使研究人员能够在一系列倾斜角度上收集相对较厚的样品的多幅图像。所有这些图像都经过数学处理，以生成原始截面的3D重建(断层图像)。增加的加速电压是允许电子束穿透样品而不出现多次或非弹性散射的关键，特别是在大倾角时，其中生物样品的塑料切片或冷冻生物样品或生物聚合物的电子断层图像的截面厚度增加一倍或近三倍，轴向分辨率为2-10 nm。新设备被安置在一个现有的、高效的校园显微镜和表征中心，由一名永久的全职博士专家管理，完全由中心预算资助，并由一个由教师用户组成的专门咨询委员会监督。新的断层扫描系统促进了校园内的许多合作，并允许来自几乎每一所学院/学校的研究人员和学生应用最先进的高分辨率成像技术。建议的EM的使用和应用的动手演示包括在PI和协理PI教授的成像课程中。此外，每年都会举办暑期讲习班，在校园内培训研究人员和学生有关断层扫描方法的知识。新的显微镜在推广方面也起到了非常重要的作用。三维断层摄影模型在视觉上是令人惊叹的表现。它们以一种非常有效的方式向每个人传递细胞结构的3D信息，从训练有素的生物学家到普通公众。新的威斯康星发现研究所(WID)在市中心有一个显微镜和成像发现利基，其中包括一个由监视器阵列组成的高分辨率显示器。新显微镜的使用所产生的断层重建图像，包括复制病毒、细胞分裂过程中的细胞骨架阵列、植物细胞器、神经元中的信号传输的图像，都显示在这些监视器上。此外，一些断层模型在3D打印机中打印，供世界卫生署和其他参与部门展示。

The intermediate voltage (300kV) electron microscope equipped with a tilting sample holder for tomography and a cryostage is serving a longstanding need to provide key imaging technologies to a wide variety of biological and bioengineering research programs on the University of Wisconsin - Madison. Users of this microscope are heavily dependent on high resolution imaging for their work on a wide range of important topics, including membrane and protein trafficking, biomineral and biopolymers, viral replication and virus-host interaction, cytoskeletal organization and cell division, nerve terminal organization and exocytosis, bacterial architecture, imaging of molecular complexes, and neuroengineering. This imaging system enables researchers to collect multiple images of relatively thick samples over a series of tilt angles. All these images are mathematically processed to generate a 3D reconstruction (tomogram) of the original section. The increased acceleration voltage is essential for allowing the electron beam to penetrate the sample without plural or inelastic scattering, especially at high tilt angles where the section thickness doubles or nearly triples Electron tomograms of either plastic sections of biological samples or cryofixed biological specimens or biopolymers results in an axial resolution of 2-10 nm. The new equipment is housed in an existing, highly effective campus microscopy and characterization center, managed by a permanent, full-time PhD expert entirely funded by the center budget, and supervised by a dedicated advisory committee of faculty users.The new tomographic system fosters many collaborations on campus and allows researchers and students from almost every single college/school to apply state-of-the-art high resolution imaging techniques. Hands-on demonstrations on the use and applications of the proposed EM are included in the imaging courses taught by the PI and co-PIs. In addition, annual summer workshops are held to train researchers and students on campus on tomographic approaches. The new microscope has also a very important role in outreach. Three-dimensional tomographic models are visually stunning representations. They convey 3D information of cellular structures in a very effective way to everyone, from highly trained biologists to the general public. The new Wisconsin Institute of Discovery (WID) has a microscope and imaging discovery niche in the Town Center that includes a high resolution display consisting of an array of monitors. Tomographic reconstructions derived from the use of the new microscope, including images of replicating viruses, cytoskeletal arrays during cell division, plant organelles, signal transmission in neurons, are displayed in these monitors. In addition, some tomographic models are printed in a 3D printer for display in the WID and other participating Departments.