Department of Biosciences, University of Helsinki, Helsinki, Finland.
Autophagy. 2011 Sep;7(9):935-56. doi: 10.4161/auto.7.9.15760. Epub 2011 Sep 1.
Autophagy was first discovered by transmission electron microscopy more than 50 years ago. For decades, electron microscopy was the only way to reliably detect autophagic compartments in cells because no specific protein markers were known. In the 1970s, however, the introduction of biochemical methods enabled quantitative studies of autophagic-lysosomal degradation, and in the 1980s specific biochemical assays for autophagic sequestration became available. Since the identification of autophagy-related genes in the 1990s, combined fluorescence microscopy, biochemical and genetic methods have taken the leading role in autophagy research. However, electron microscopy is still needed to confirm and verify results obtained by other methods, and also to produce novel knowledge that would not be achievable by any other experimental approach. Confocal microscopy, with its ever-improving resolution, is probably the best-suited morphological approach to investigate the dynamic aspects of autophagy. However, for analyzing the ultrastructural details of the many novel organelles and mechanisms involved in specific subtypes of autophagy, the electron microscope is still indispensable. This review will summarize the impact that electron microscopy has had on autophagy research since the discovery of this self-degradation process in the mid-1950s. Astonishingly, some of the "novel" concepts and principles of autophagy, presented in the recent studies, were already proposed several decades ago by the pioneering, accurate and passionate work of virtuoso electron microscopists.
自噬现象最初是在 50 多年前通过透射电子显微镜发现的。几十年来，由于没有已知的特定蛋白质标志物，电子显微镜是唯一能够可靠地检测细胞中自噬隔室的方法。然而，在 20 世纪 70 年代，生化方法的引入使自噬溶酶体降解的定量研究成为可能，而在 20 世纪 80 年代，自噬隔离的特定生化测定方法也变得可用。自 20 世纪 90 年代鉴定出自噬相关基因以来，荧光显微镜、生化和遗传方法已在自噬研究中占据主导地位。然而，电子显微镜仍然需要用于确认和验证其他方法获得的结果，并且还需要产生任何其他实验方法都无法获得的新的知识。随着分辨率的不断提高，共聚焦显微镜可能是研究自噬动态方面的最佳形态学方法。然而，对于分析涉及特定自噬亚型的许多新细胞器和机制的超微结构细节，电子显微镜仍然是不可或缺的。本文综述了自噬现象在 20 世纪 50 年代中期被发现以来，电子显微镜对自噬研究的影响。令人惊讶的是，一些最近研究中提出的“新颖”的自噬概念和原理，早在几十年前就已经被电子显微镜大师们富有开创性、准确性和激情的工作所提出。
