Fungi and Electron Microscopy

More than 1000 fungi are currently presented in the exhibition “Fungi: Food, Poison and Mythology” by the Museum Wiesbaden. But what does this have to do with electron microscopy? Dr. Armin Zankel realised the 3D reconstruction of five different spores by means of scanning electron microscopy. The microscopic reconstructions have been magnified and 3D printed. Now they are being displayed for more than a year until August 5th 2018.

If you happen to be in Wiesbaden: it’s definitely worth passing by!

Mycology Meets Electron Microscopy

The German preparation experts Liselotte and Klaus Wechsler got in contact with us in order to get 3D reconstructions of spores. Since these “units of reproduction” are very small a method using electron microscopy was chosen. Dr. Armin Zankel realized the 3D reconstruction of five different spores by means of “in situ ultramicrotomy in the ESEM” (Environmental Scanning Electron Microscope).

The microtome, which is mounted into the specimen chamber of the electron microscope (EM), cuts the sample slice by slice. After each slice an EM image is stored. As a result of the series of images a 3D reconstruction of a specimen can be performed. The samples in the present case were blocks of dried resin with embodied spores. As a result Klaus Wechsler produced 3D model of diameter of several decimeters. Since the spores have diameters in the range of some microns (e.g. 5 µm) and the models have a diameter in the range of decimeters this means a magnification of 20.000x.

 

From the spore to the 3D model

Embedding the spores in resin, drying of the resin, precutting of the block in the institutes’ microtomy unit (Ing. Claudia Mayrhofer), mounting the specimens in the in situ ultramicrotome, alignment of the electron microscope and “slice and view” of the samples, getting a stack of images, 3D reconstruction of the spores (Dr. Manfred Nachtnebel), exporting it in the data format for 3D printers, production of masters with the 3D printer, producing of casting mould with the help of the real 3D prints and finally producing several 3D models by filling in polymer into the mould. The steps after 3D printing were performed by the preparation expert Klaus Wechlser.

As a result several 3D representations of different scale can be found in the exhibition. Additionally some paintings on the wall of the museum are magnified images of conventional characterisations of spores performed with the scanning electron microscope ESEM in the low vacuum mode.

Want to know more?

Museum Wiesbaden: Fungi: Food, Poison and Mythology

Read the article: Synergy of SEM and Ultramicrotomy

3D and in situ Characterisation

Methods