Why is Imaging Important for Cellular Meso-Sciences and Meso-Control?

1. Knowing the morphology and structure is the first step toward understanding meso systems.

The meso-scale refers to the space scale mainly between 5 to 100 nm (another definition of 3 to 300 nm is useful, and is used here).

For observing meso-scale molecular complexes, the spatial resolution of a single molecule (several nanometers) is required.

For more precise knowledge of the shapes and structures of meso-systems, electron microscopy is useful, because it allows observations with a spatial resolution of 1 nm for biological specimens (mostly determined by the method of specimen preparation, rather than the power of the microscope).

2. To understand how biological meso-systems form and work, one must know how the nano components (single molecules) that form the system actually move in the system. Since their movements occur stochastically, and are dominated by thermal fluctuations and diffusion, and since such stochastic/oscillatory movements are critical for the formation and function of meso-systems, the movements must be observed at the level of single molecules, or of each nano component.

3. Partially due to their small sizes, meso-architectures are extremely dynamic in the cell; i.e., the formation, disassembly, and function of these meso-architectures occur dynamically. Therefore, to elucidate the mechanisms underlying the formation and function of meso-architectures, it is extremely useful to simultaneously track the movements of many individual single molecules in situ.

4. Measurements of mean values ensemble-averaged over many molecules, which are commonly performed, may not be very useful or informative to understand the events occurring in living cells, because each molecule in a cell is unique, in that it is experiencing a particular environment, in terms of its confined space, signaling context, and binding partners.

5. The intermolecular interactions, particularly those involving water molecules, are fundamentally important for understanding the mechanisms of the formation and function of biological meso-structures. One of the most promising new technologies for studying such molecular interactions is terahertz spectroscopy/microscopy.
Prof. Tanaka of the CeMI is leading the world in this field.

6. Quick-freeze, deep-etch, platinum replication electron microscopy

The CeMI promotes this method, because it allows biological meso-structures to be observed by electron microscopy under the most natural conditions possible, without chemical fixation and drying. Prof. Heuser, the inventor of this method and a core CeMI member, is regarded as a world treasure, due to his ability to produce fundamentally important, as well as stunningly beautiful, electron micrographs. His technique skillfully combines quick-freezing and electron microscope imaging.

Go back to Top