Organised by WEES, a group of junior scientists from various research groups across Wageningen University.
By Berenike Maier
Institute of Theoretical Physics, University of Cologne, Germany
Horizontal gene transfer is common among bacteria. This talk will focus on bacterial transformation, namely the import and inheritable integration of DNA from the environment. In the first part of the talk, the process of DNA uptake will be considered. The translocation of polymeric DNA through the cell envelope is a key step of transformation. The proteins forming the DNA uptake machine have been identified. Yet, the biophysical mechanism of the motor pulling DNA from the environment into the bacterial cell remains poorly understood. Single molecule approaches were therefore used for studying the mechanism of DNA uptake. The results are in remarkable agreement with a translocation ratchet model, whereby a periplasmic chaperone rectified DNA diffusion through the membrane by reversible binding. The second part of this talk will address fitness trade-offs of the state of competence for transformation. Bioinformatic analyses provide ample evidence for gene transfer between species. However, the costs and benefits of gene transfer remain poorly understood. In Bacillus subtilis, competence for transformation is transient and associated with a distinct physiological state. In particular, competent cells are growth-arrested conferring considerable cost. The mechanism of stochastic differentiation into the state of competence as a fitness-tradeoff in changing environments will be discussed.
Prof. Dr. Berenike Maier is the Professor for Biophysics at the Institute of Theoretical Physics, University of Cologne. Her research uses innovative approaches from physics to better understand bacterial systems. This work addresses questions such as how bacteria generate forces for DNA uptake and coordinate multiple motors for movement, and how biofilms are shaped by the different interaction forces between bacterial cells. Her laboratory has also started focussing on the evolutionary implications of single-molecule processes, including the costs of horizontal gene transfer and the spread of genes in structured populations.
Time and location
The seminar will start at 16:00 and be followed by drinks.
Lecture room number C3033, Orion Building 103, Bronland 1, Wageningen.
If you are interested in joining the discussion prior to the seminar, contact Mark Zwart. The discussion will take place from 13:30 – 15:00 at C4030 in the Orion building and is meant for MSc and PhD students. Registration is required. Only 15 places are available for the workshop and attendance occurs on a first come first serve basis.