Seminar by Yohan Davit / Institut de Mécanique des Fluides de Toulouse
Monday 20th of February 2017 - 2pm - Maroni room / MHT
His talk will give some answers to this question: can mechanical effects control the ecology of bacterial biofilms?
Biofilms are consortia of microorganisms that grow on surfaces such as the curtain of your shower, the drinking water pipes of your house or rocks in the river. They represent the dominant form of life for most bacteria, well above the planktonic phenotype. They have a considerable sanitary, ecological and economic impact. For instance, biofilms drive crucial ecosystem processes in aquifers and contribute to biogeochemical cycles. They are also used in bioremediation, filtration and bioreactor technologies. It is therefore important to understand the mechanisms that control their ecology and how they are affected by environmental stresses.
In this talk, he will focus on two different mechanical effects that influence the ecology of bacterial biofilms. He will start by presenting how the shape of individual bacteria can yield spatial patterning inside the communities, which in turn can affect the fitness of competing strains. This patterning is driven by mechanical interactions at the cellular-level that we study using computational models and imaging of colonies using confocal laser scanning microscopy. He will then go on to discuss the impact of hydrodynamic conditions and heterogeneities on biofilms in porous media (such as those in aquifers for example), which they study using x-ray computed microtomography and two-photon microscopy. Approaches based on x-ray tomography are still being developed, but they are proving extremely powerful in studying couplings between the morphology of the biofilms, the pore-scale geometry and the flow.