National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 100052, China.
Nat Commun. 2020 Jun 2;11(1):2773. doi: 10.1038/s41467-020-16391-6.
Cryo-electron microscopy is an essential tool for high-resolution structural studies of biological systems. This method relies on the use of phase contrast imaging at high defocus to improve information transfer at low spatial frequencies at the expense of higher spatial frequencies. Here we demonstrate that electron ptychography can recover the phase of the specimen with continuous information transfer across a wide range of the spatial frequency spectrum, with improved transfer at lower spatial frequencies, and as such is more efficient for phase recovery than conventional phase contrast imaging. We further show that the method can be used to study frozen-hydrated specimens of rotavirus double-layered particles and HIV-1 virus-like particles under low-dose conditions (5.7 e/Å) and heterogeneous objects in an Adenovirus-infected cell over large fields of view (1.14 × 1.14 μm), thus making it suitable for studies of many biologically important structures.
冷冻电子显微镜是生物系统高分辨率结构研究的重要工具。该方法依赖于在高离焦下使用相位对比成像来提高低空间频率处的信息传递，代价是更高的空间频率。在这里，我们证明电子相衬术可以通过在宽频谱范围内连续传递信息来恢复样品的相位，从而在较低的空间频率处提高传递，因此比传统的相位对比成像更有利于相位恢复。我们进一步表明，该方法可用于在低剂量条件（5.7e/Å）下研究双层轮状病毒颗粒和 HIV-1 病毒样颗粒的冷冻水合标本，以及在大视场（1.14×1.14μm）下研究腺病毒感染细胞中的异质物体，因此非常适合研究许多对生物学很重要的结构。
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