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Why is it important?
Until now, characterization of translational diffusion in live cells has almost exclusively relied on measurements of constant translational diffusion coefficients. In live cells there is some evidence that the apparent translational diffusion coefficients may not be constant, but instead can vary over time, even for inert molecules. See: Baumann G, Kinjo M, Földes-Papp Z*. Anomalous Subdiffusive Measurements by Fluorescence Correlations Spectroscopy and Simulations of Translational Diffusive Behavior in Live Cells. J Biol Methods 2014;1(1):e3. doi: 10.14440/jbm.2014.17
Perspectives
Separation of the spatial subdiffusion from the temporal subdiffusion: https://www.growkudos.com/publications/10.14440%252Fjbm.2014.17/reader
PRESERVE FROM BEING FORGOTTEN: Professor Zeno Földes-Papp [Biochemist, Gerontologist (Biochemiker, Geriater)]: Laying the Foundation of Single-Molecule Biophysics & Biochemistry Based On the Stochastic Nature of Diffusion: The Individual Molecule, from the Mathematical Core to the Physical Theory. -- I hope that my humble scientific work will be well received by the communities of single-molecule imaging and spectroscopy and by all users of these technologies as well as biotechnologies in the various and different disciplines:
Head of Geriatric Medicine (Medical Director of the Geriatric Service: Sektionsleitung Geriatrie) at Asklepios Klinikum Lindau (Bodensee), Bavaria, Germany
Read the Original
This page is a summary of: Mobility and distribution of replication protein A in living cells using fluorescence correlation spectroscopy, Experimental and Molecular Pathology, April 2007, Elsevier,
DOI: 10.1016/j.yexmp.2006.12.008.
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Resources
Anomalous subdiffusive measurements by fluorescence correlations spectroscopy and simulations of translational diffusive behavior in live cells
Trapping of molecules in live cells can exert at least two types of effects that could be important for function. First, live cells will have a strong influence on how far and how fast locally produced molecules will travel within the cytoplasm or the nucleoplasm. Over a time scale of 1 s, a molecule with an apparent diffusion coefficient Dapp of 2 μm2/ms, would diffuse about 60 μm. Thus, as long as molecules remained within the cytoplasm, their movement could be dominated by an anomalous diffusion process over distances. Second, anomalous diffusion reflects an increase in the spatial and temporal correlation of diffusing molecules which would be expected to promote activation of biochemical networks by intracellular signals trapped in live cells
Basic theory of anomalous subdiffusive motion (transport)
Separation of the spatial subdiffusion from the temporal subdiffusion.
Meaningful Interpretation of Subdiffusive Measurements in Living Cells (Crowded Environment) by Fluorescence Fluctuation Microscopy
In living cell or its nucleus, the motions of molecules are complicated due to the large crowding and expected heterogeneity of the intracellular environment. Randomness in cellular systems can be either spatial (anomalous) or temporal (heterogeneous). In order to separate both processes, we introduce anomalous random walks on fractals that represented crowded environments. We report the use of numerical simulation and experimental data of single-molecule detection by fluorescence fluctuation microscopy for detecting resolution limits of different mobile fractions in crowded environment of living cells.
Individual Macromolecule Motion in a Crowded Living Cell
Without choosing the proper equations for anomalous subdiffusive behavior in cellular applications, the fitted biological system response parameters and the interpretations of the FCS and dual color FCCS data are likely meaningless and wrong, respectively. Equations based on normal diffusion are not valid in the crowded and dynamic environment of a living cell.
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