What are the two main benefits of using a stereomicroscope?.What are 2 advantages of using a compound light microscope?.What are the advantages and disadvantages of using a compound light microscope?.Can light microscopes see living cells?.What’s a disadvantage of a light microscope?.What are the advantages of using a light microscope?.How is light microscopy different from electron microscopy?.When would it be appropriate to use an electron microscope instead of a light microscope?.Why light microscopes are better than electron microscopes?.Sigmund, Pettinger, Jube et al.:”Iron-sequestering nanocompartments as multiplexed Electron Microscopy gene reporters, ACS Nano, DOI: 10.1021/acsnano. ** Sigmund et al.: „Bacterial encapsulins as orthogonal compartments for mammalian cell engineering“, Nature Communications, DOI: 10.1038/s41467-3 * Scientists from Helmholtz Zentrum München, Technical University of Munich (TUM), the German Center for Neurodegenerative Diseases (DZNE), the University of Tübingen, the Max Planck Institute of Neurobiology and the Lomonosov Moscow State University were involved in the project. This new technology could thus help to uncover the exact wiring diagram of brains and to investigate closer how memories are stored in neuronal networks. "With our new reporter genes, we could label specific cells and then read out which type of nerve cell makes which connections and which state the cells are in," adds Westmeyer.
Despite the impressive resolution of electron microscopy, the method can still not reliably distinguish certain types of neurons within the brain. With their new method, the researchers will now also investigate neural circuits. This special material property of encapsulins makes them clearly visible in the images. Metals create good contrasts because they "swallow" electrons - comparable to dense bones in the X-ray image, which strongly absorb X-rays. This creates insoluble iron oxides that remain inside. If iron ions enter the interior lumen through pores of the nano compartments, the enzyme oxidizes divalent iron ions into their trivalent form. To achieve strong contrast in the images from the electron microscopy, the researchers use the enzyme ferroxidase, which can be enclosed in the interior of encapsulins. "Analogous to the palette of colors in fluorescence microscopy, our method turns geometry into a label for electron microscopy," adds Felix Sigmund from Westmeyer's research group. Depending on the experimental conditions, nanocompartments with different diameters are formed within living cells via genetic programming. Encapsulins automatically assemble to nanocompartments in which chemical reactions can run without disturbing the metabolism of the cell. Westmeyer and colleagues* have been working with so-called encapsulins** for some time, which are small, non-toxic proteins from bacteria. Nanocompartments as multi-color labels for electron microscopy He leads a research group at the Institute for Biological and Medical Imaging (IBMI) of Helmholtz Zentrum München and is Professor of Molecular Imaging at Technical University of Munich (TUM), School of Medicine. Although electron microscopes allow a closer look, "so far there are hardly any solutions for multi-color genetic labeling of cells for this technology, such that one can directly tell different cells apart", says Prof. This method works well but has disadvantages due to the relatively poor resolution of light microscopes. To label small structures, scientists have been using fluorescent proteins. What exactly is going on in cells? This question has kept scientists busy for decades. Size matters to bring color to Electron Microscopy © Barth van Rossum