Transmission Electron Microscopy (TEM)
Our FEI Tecnai 200 kV TEM with a Gatan Imaging filter GIF2002 and a motorized goniometer offers us the application of 3D-electron tomography and Electron Energy Loss Spectroscopy (EELS). Digital imaging is carried out with an Olympus Veleta CCD Camera (side mount) and a Gatan 2k x 2k CCD-Camera (bottom mount).
The TEM is most frequently used to examine the architecture of plant cells and localization of macromolecules, particularly proteins, in cell compartments. Conventional chemical fixation (aldehyde, osmium) is used for routine ultrastructural research (Lowicryl, Spurr, LR White). Steadily growing is the interest in the cellular distribution and localization of proteins and enzymes in wild type and transgenic plants employing TEM. Currently the most advanced method to address these problems is use of immunogold electron microscopy. To ensure that the cell structure and momentum location of a particular protein do not change, workable techniques of sample cryo-fixation and cryo-substitution for plant and animal tissues and micro-organisms with a relative high through-put have been established. Even High-Pressure-Freezing (HPF) can be applied for roots, pollen and anthers and is being improved technically for other applications.
Cellular tomography using transmission electron microscopy (TEM) is the only available technology to chart the inside of a cell. Imaging the cellular structures in all three dimensions to generate an accurate three-dimensional map of the interior of the cell, enables researchers to analyze molecular structures in relation to the cellular architecture, the cytoskeleton and the cell organelles. Most proteins do not function as individual entities, but in coordination or dependence with other proteins. The knowledge of the three-dimensional organization is essential to understand protein function at the cellular level.
Transmission electron microscope FEI Tecnai G2-Sphera 200 KV
Energy filter system Gatan GIF 2002
Olympus EMCCD Veleta (2k x 2k, side mount)
Gatan EMCCD (2k x 2k, bottom mount)
Image processing software: TIA, SIS, Amira