Electron tomography methods using the conventional transmission electron microscope have been widely used to investigate the three‐dimensional distribution patterns of various cellular structures including microtubules in neurites. Because the penetrating power of electrons depends on the section thickness and accelerating voltage, conventional TEM, having acceleration voltages up to 200 kV, is limited to sample thicknesses of 0.2 µm or less. In this paper, we show that the ultra‐high voltage electron microscope (UHVEM), employing acceleration voltages of higher than 1000 kV (1 MV), allowed distinct reconstruction of the three‐dimensional array of microtubules in a 0.7‐µm‐thick neurite section. The detailed structure of microtubules was more clearly reconstructed from a 0.7‐µm‐thick section at an accelerating voltage of 1 MV compared with a 1.0 µm section at 2 MV. Furthermore, the entire distribution of each microtubule in a neurite could be reconstructed from serial‐section UHVEM tomography. Application of optimised UHVEM tomography will provide new insights, bridging the gap between the structure and function of widely‐distributed cellular organelles such as microtubules for neurite outgrowth.

中文翻译：

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超高压电子显微镜断层扫描在培养的 PC12 细胞神经突微管 3D 成像中的应用

使用传统透射电子显微镜的电子断层扫描方法已被广泛用于研究包括神经突中微管在内的各种细胞结构的三维分布模式。由于电子的穿透能力取决于切片厚度和加速电压，因此具有高达 200 kV 加速电压的传统 TEM 仅限于 0.2 µm 或更小的样品厚度。在本文中，我们展示了超高压电子显微镜 (UHVEM)，采用高于 1000 kV (1 MV) 的加速电压，允许在 0.7 µm 厚的神经突中对三维微管阵列进行明显的重建部分。与 1 MV 相比，在 1 MV 的加速电压下，从 0.7 微米厚的部分可以更清楚地重建微管的详细结构。2 MV 处的 0 µm 部分。此外，可以从连续切片 UHVEM 断层扫描重建神经突中每个微管的整个分布。优化的 UHVEM 断层扫描的应用将提供新的见解，弥合广泛分布的细胞器（如用于神经突生长的微管）的结构和功能之间的差距。