To fulfill their role within a living organism, the localization as well as their 3-dimensional distribution and organization of certain proteins is absolutely crucial. As our group is responsible for the electron microscopic facility with several high-end microscopes and preparation units, we are not only investigating the protein localization in and the ultrastructure of plant cells but also in other eukaryotic systems and various microorganisms. Amongst others, we are investigating the ultrastucture of the ammonia-oxidizing archaeon Nitrososphaera viennensis or the cold-loving euryarchaeon Candidatus ‚Altiarchaeum hamiconnexum’ (strain SM1).
Within an ongoing cooperation with the group of Prof. Uwe-G. Maier (Philipps-Universität Marburg), we also try to illustrate the ultrastructure of the photosynthetic microalga Phaeodactylum tricornutum. This alga evolved by a so-called secondary endosymbiosis. These organisms face several organizational difficulties, as nuclear encoded plastidal proteins have to pass up to four membranes to get to their site of action within the complex plastid. A primary localization of GFP-fusion proteins using a confocal fluorescent microscope is followed by high-resolution immunogold localization studies using a high-pressure freezer and subsequent transmission electron microscopy. For the 3-dimensional organization of the cells, FIB/SEM tomography is the method of choice.
This offers a great variety of projects with the application of electron microscopical preparation and illustration methods as common feature.