For super resolution microscopy, a STED super resolution scanning confocal microscope (Leica, TC S SP8 STED) and a SIM/PALM (Zeiss, Elyra) microscope are available. The current infrastructure of the unit further comprises several epifluorescence microscopes, some of which are modified for single molecule microscopy (SMM), for total internal reflection fluorescence (TIRF) microscopy and for fluorescence recovery after photobleaching (FRAP).

The stimulated emission depletion super resolution scanning confocal microscope (Leica, TCS SP8 STED). (Photo: Rolf K. Wegst)

Leica G-STED

This superresolution microscope uses scanning confocal microscopy as basic technique, and obtains a resolution of 50 nm using chromophores such as YFP or dyes with excitation at 514 nm. Also applicable are chromophores with excitation at 488 nm (GFP, FITC), down to 457 nm (CFP), but resolution decreases moving away from 514 nm. The microscope also offers a white laser excitation, in which all wavelengths between 470 nm to 670 nm can be tuned within 1 nm regimes. The microscope can also perform line-FRAP for measuring fast diffusion rates. The microscope is suitable for time lapse (dual colour is possible) microscopy only in the regular confocal mode.

Zeiss Elyra PS1

Zeiss Elyra PS1

This superresolution microscope offers to SRM techniques, SIM and PALM. In SIM, 9 images are taken during which illumination patterns are changed, to double the limit of resolution of light microscopy. 3D analyses are possible as well as time lapse microscopy (in the range of 1 to 2 pictures per second). This technique uses soft illumination and is therefore ideal for sensitive experiments and time resolved microscopy, yielding double increase in vision. PALM uses photo-activatable dyes or fluorescent proteins and operates in a stochastic manner, only a small subset of molecules is excited, visualized with very high precision (down to 20 nm), and bleached, for multiple rounds. These analyses yield highest resolution, but are usually performed on fixed cells to avoid molecule movement during the acquisition time. The Elyra is 3D useable for PALM.

SMT

SMT

Single molecule tracking allows measuring diffusion rates, determining if populations with distinct diffusion rates exist (e.g. bound and freely diffusing proteins), determine diffusion rates of different populations, measure average resting times (during which proteins are usually bound somewhere), and visualize subcellular sites of fast and slow movement. Presently, YFP-based proteins can be tracked, a new setup for SMT using red fluorescent proteins will be up soon. This technology ideally complement SRM techniques like STED, SIM or PALM.

Multicolour TIRF with FRAP

TIRF-M

Total internal reflection microscopy excites only to a depth of 100 nm, which is ideally suited to visualize fluorescent membrane proteins or proteins that operate adjacent to a membrane. Our 2 setups allow the use of UV, blue, green, yellow and red excitation, and the combination with Fluorescence Revovery after Photobleaching (FRAP). This technique uses bleaching of a small area within cells and determines protein mobility by measuring regain of fluorescence within the bleached area over time. Differential FRAP can determine association constants of protein complexes within live cells, which is done in the “Flow Cytometry & Imaging Facility” of the MPI Micter http://www.mpi-marburg.mpg.de/facs. Our TIRF microscopes are based on Zeiss Axioobservers, feature fast EM-CCD cameras and can also be used for regular wide field microscopy, including 3D reconstruction and time lapse microscopy.

Wide field fluorescence microscopy

Wide field fluorescence microscopy

Regular FM can be done on two Olympus microscopes with up to 8 filter combinations, Nomarski DIC, 3D stack acquisition and microscope automatization.

SYNMIKRO Young Researchers Groups

Almost all scientific members of SYNMIKRO are actively involved in DFG’s Collaborative Research Centers (Sonderforschungsbereiche), Research Training Groups (Graduiertenkollegs), or other Cooperative Research projects. Alongside performing adventurous experiments, and reporting excellent science, SYNMIKRO substantially promotes potential Young Research Group Leaders by constantly keeping its doors open to welcome and support Young Researchers planning to set up an Independent Research Group.
Our Young Research Groups