Growth and division of single bacterial cells; Time-lapse microscopy together with image processing; protein-DNA interaction at thesingle molecule level
Interactions and physical properties of biological molecules; Advanced optical and molecular biology techniques.
FTIR-Microspectroscopy; FTIR-spectroscopy;Fiber Evanescent Wave Spectroscopy
Single Cell Dynamics (Feingold's Group)
We use single cell phase-contrast and fluorescence time-lapse microscopy to monitor morphological changes during the division of E. coli. To bypass the limitations of optical resolution, we process the images using pixel intensity values for edge detection. We study the dynamics of the constriction width, W, and find that its formation starts shortly after birth much earlier than can be detected by simply viewing phase-contrast images. A simple geometrical model is shown to reproduce the behavior of W(t). Moreover, the time-dependence of the cell length, L(t), consists of three linear regimes.
Internal dynamics of biological polymers: DNA molecules, actin filaments (Krichevsky's Group)
The problem of polymer dynamics is rather old, going back to the 1930-s.
How the stochastic thermal motion (diffusion) reveals itself in the dynamics of polymer segments which are bound by connectivity along the chain, by polymer stiffness, by topological constrains, by hydrodynamic and other interactions?
The question does not have simple solutions in neither theory, computer simulations, or experiments. We have developed an original experimental approach to measure the dynamics of biological polymers, such as DNA at the level of single monomer with high temporal and spatial resolution.