Mobility is Important for Cellular Function

The fluid mosaic model of Singer and Nicolson (1972) and its subsequent extensions (Simons and Vaz 2004 Jacobson et al. 2007 Kusumi et al. 2005) point to the importance of mobile membrane components and intracellular membrane flow for the proper function of biological cells. Molecular interaction partners, especially those involved in signaling cascades, must diffuse laterally to be able to meet and interact, and thereby initiate chemical reactions (Khan and Pessin 2002 Pierce et al. 2002)....

Background Subtraction

In spite of optimization of the culture conditions the autofluorescence in D. discoideum remained significant and turned out to be highly inhomogeneous within the cell. Therefore an algorithm was developed to subtract an inhomogeneous, time-varying Figure 5.3 Data analysis. (A) A 50 x 50 pixel image from an image stack of 100 images taken at the apical membrane of an unstimulated D. discoideum cell. (B) Sliding mean image from the image stack generated with Gaussian weight around the current...

Berciaud Histidine

Barbarossa, P. Anderson, and B. S. Hansson 2003 . Extreme sensitivity in an olfactory system. Chem Senses 28 279-284. Asamoah, O. K., J. P. Wuskell, L. M. Loew, and F. Bezanilla 2003 . A fluorometric approach to local electric field measurements in a voltage-gated ion channel. Neuron 37 85-97. Axelrod, D., T. P. Burghardt, and N. L. Thompson 1984 . Total internal reflection fluorescence. Annu Rev Biophys Bioeng 13 247-268. Bacia, K., S. A. Kim, and P. Schwille...

Single Molecule Microscopy and Force Spectroscopy of Membrane Proteins

Andreas Engel , Harald Janovjak, Dimtrios Fotiadis, Alexej Kedrov, David Cisneros, and Daniel J. M ller 280 11.2 High-Resolution Imaging Using Atomic Force 282 11.2.3 Optimizing Conditions for Contact Mode 283 11.2.4 Determining Oligomeric State and 286 11.2.6 AFM, a Structural Biology Method Complementing 11.2.7 Observing the Diffusion of Single Membrane Proteins 288 11.2.8 Observing Structural Flexibility of Membrane 289 11.2.9 Imaging Conformational Changes of Native Membrane Proteins 292...

Mass Transport in Nanotube Vesicle Networks

In order to take full advantage of lipid nanotube-vesicle networks NVNs as systems for performing operations with single molecules, including initiating and controlling chemical reactions, ways to transport materials through the nanotubes are of central importance. There are three fundamental transport mechanisms available Figure 9.3 . The first, Marangoni transport, is based on membrane tension gradients and utilizes the dynamic and fluid character of the bilayer membrane. The second is...

Tension Controlled Marangoni Lipid Flow and Intratubular Liquid Flow in Nanotubes

If there is a tension difference along the interface of a fluid system, this can give rise to a flow Bloom et al. 1991 Dommersnes et al. 2005 Finkelstein 1987 . Interfacial tension-driven flows are generally called Marangoni flows and examples of this flow behavior are spreading of a film on an air-water interface or wetting of a dry solid substrate by a film de Gennes 1985 Probstein 1994 . For a film of thickness e, a shear flow in the direction of the tension gradient is given by where z is...

Statistical Analysis

The relevant questions to be answered with SPT are the following. Is the motion of molecules in a 2D biological membrane Brownian, anomalous or confined What are the characteristic parameters of the particular mode of motion, for example, the diffusion coefficient, the degree of anomality, or the confinement size Are these properties invariant or do they depend on the state of the molecule or the environment such as the state of development of the cell Is the ensemble of molecules homogeneous...