The chronicles of coronaviruses: the electron microscope, the doughnut, and the spike

The advancement of medicine owes in large measure to a German engineer Ernst Ruska, whose invention of transmission electron microscope in 1931 won him the 1986 Nobel Prize in Physics, when it comes to infectious diseases. Encouraged by his physician brother Helmut Ruska to use the prototype instrument for the study of viruses, the course of virology was shifted to a different and unprecedented level. Virus could then be seen, identified and imaged. The University of Maryland happened to acquire an American model of transmission EM, the RCA EMU, using which the first structural study was done for the first known coronavirus (then was simply known as infectious bronchitis virus) in 1948. The virus was described as rounded bodies with filamentous projections. The magnification was not great and the resolution was poor. The study was followed by a series of studies using improved techniques and better EM spanning the next decade. An upgraded version RCA-EMU2A gave better images in 1957 and the virus was described as doughnut-like structure. Using Siemens Elmiskop, D.M. Berry and collaborators made the first high-resolution pictures in 1964. The thick envelope which gave doughnut-like appearance and filamentous projections reported before could be discerned as discrete pear-shaped projections called the spikes. These spikes form a corona-like halo around the virus, which were also seen in novel human viruses (B814 and 229E) that caused common colds. The discoverer of B814, David Tyrrell and his aid June Almeida, a magnificent electron microscopist, established that IBV, B814 and 229E were of the same kind of virus in 1967, which prompted to create the name coronavirus in 1968. This article further highlights the detail structural organisation of coronaviruses emanating from these pioneering research.

From cells to chiffon: Reminiscence of an electron microscopist

For a scientist, using the electron microscope can be a life-altering experience. One sits in the dark, usually alone, looking for answers to particular puzzles. Where is this immuno-tagged protein located? Why is it in this place, in this cell, in this particular site? Wait a minute! What is this unusual structure? Why does it have this strange shape? What is this density inside? Why does it seem to interact with the Golgi body?

Dehydration and Rehydration Issues in Biological Tissue Processing for Electron Microscopy

Electron microscopy (EM) is an indispensable tool for the study of ultrastructures of biological specimens. Every electron microscopist would like to process biological specimens for either scanning electron microscopy (SEM) or transmission electron microscopy (TEM) in a way that the specimens viewed under the electron microscope resemble those seen in vivo or in vitro under the light microscope. This is, however, often easier said than done because biological tissue processing for EM requires careful attention of the investigator with regard to the numerous processing steps involved in specimen preparation, such as fixation, dehydration, infiltration, embedding, and sectioning.

Popcorn, Diffraction and the Computer Revolution

As is the case with many other aspects of our lives here in the twilight years of the twentieth century, the computer is having an evermore pervasive role in the daily endeavors of the electron microscopist. And as I contemplate the little button on the microwave that allows me to burn popcorn the exact same way, time after time, I am led to wonder “where is it all going?”…the technology that is. I know where the burnt popcorn will end up. Whether we like it or not, the computer is a tool that can drastically improve our productivity, and typically such productivity gains occur precisely within those tasks where mistakes are the most likely to creep in, to wit: the mundane and repetitive.As an example, consider the task of indexing a diffraction pattern for a known crystal. In the far distant and superstitious past of the mid to late 1960's, this task required all sorts of strange alchemy.