Collective dynamics of cells
Previous and Current Research
It is fascinating to follow how individual cells can organize and develop complex and robust structures, which are reminiscent of a living organism. We apply and develop methods of statistical physics to get a better understanding of multicellular dynamics and self-organization.
Biofilms is one example of such systems that motivated our recent research. A biofilm is a complex multi-cellular community of bacteria embedded into an extracellular matrix which mainly consists of polysaccharides self-produced by bacteria. About 80% of all microbial infections involve biofilms. Other negative consequences of biofilms’ existence include contamination of medical devices and biofouling, while their positive contribution is utilized for waste remediation and microbial fuel cells. The life cycle of the biofilm starts when planktonic bacteria swimming in a fluid attach to a surface and agglomerate to form micro-colonies. The colonies grow and merge and bacteria start to produce the polymer matrix that encases the cells of the biofilm. A developed biofilm is resilient to external stresses, mechanically stable, and has a complex geometry.
- In the past we studied how the internal structure of a biofilm in the form of the network of interconnected channels facilitated the transport of nutrients inside the bacterial colony.
- We also worked to identify stochastic processes that could be used to quantify the motility of individual cells and help to uncover microscopic principles of this motility. We now start to incorporate interactions between the cells to describe their clustering. These interactions can be due to the direct cell-to-cell contact via some cell appendages or indirect via signaling chemicals.
- In another project we study motility patterns of swimming and twitching bacteria and try to understand how these patterns relate to the chemotactic behavior of cells. We also investigate the process of microcolony formation by N. gonorrhoeae bacteria, a stage that corresponds to the onset of the infectious gonorrhea disease.
- Our group is also continuously working on the theory of anomalous diffusion and random walks[3,4].
Future Projects and Goals
In our future research we would like to address the following questions that are inspired by a close collaboration with experimental groups:
- Upon fertilization, the embryonic genome is inactive and transcription only starts during the maternal to zygotic transition. It is unclear how repression and activation of transcription in the early embryo are regulated. We would like to better understand the maternal to zygotic transition. Our goal is to develop a model of this transition that complies with available experimental data. (In collaboration with the group of Nadine Vastenhouw, MPI-CBG).
- Meiotic division in the fission yeast Schizosaccharomyces pombe has a characteristic phase of nuclear oscillations that are necessary for a proper process of homologous chromosome pairing and recombination. Our goal is to build a physical model of this process in order to reveal the biophysical mechanisms underlying chromosome pairing (In collaboration with the group of Iva Tolić-Nørrelykke, MPI-CBG)
- Starting from single cells and extending our modeling to microcolonies of N.gonorrhoeae bacteria we want to understand how those cells use multiple, long, and flexible filaments called pili to move on a surface and interact with each other. (In collaboration with the group of Nicolas Biais, Columbia University/CUNY Brooklyn College)
Methodological and Technical Expertise
- biological physics
- stochastic processes
- cell motility
- random walks
 J. N. Wilking, V. Zaburdaev, M. De Volder, R. Losick, M. P. Brenner, D. A. Weitz
Liquid transport facilitated by channels in Bacillus subtilis biofilms
PNAS Published online before print, [doi:10.1073/pnas.1216376110] (2012)
 V. Zaburdaev, S. Uppaluri, T. Pfohl, M. Engstler, R. Friedrich, and H. Stark
Langevin dynamics deciphers the motility pattern of swimming parasites
Phys. Rev. Lett. 106, 208103 (2011)
 V. Zaburdaev, S. Denisov and P. Hanggi
Perturbation spreading in many particle systems: a random walk approach
Phys. Rev. Lett. 106, 180601 (2011)
 V. Zaburdaev, M. Schmiedebegr, and H. Stark
Random walks with random velocities
Phys. Rev. E. 78, 011119, [Virtual Journal of Biological Physics Research, 16(3)] (2008)