Our team is investigating the role of the bacterial actin cytoskeleton (MreB) in various fundamental cellular processes, including cell wall biogenesis, but also cell division, competence, viral infection, secretion, … Our research activities mainly focus on the description and understanding of molecular mechanisms and the machineries involved in these different processes to establish a complex network of molecular interactions at the cellular level. To carry out these investigations and to understand how these mechanisms are controlled spatially and temporally, we rely on multidisciplinary approaches, from genetics, genomics, biochemistry, mathematical modeling and microscopy (from conventionnal to and super-resolution fluorescence microscopy).
The application of fluorescence microscopy for microbiology faces two major constraints: (i) the small size of cells compared to the spatial resolution limit imposed by optical diffraction (~ 4 to 10 times larger) and ( ii) the limited amounts of fluorescent molecules in the cells (fast photo-bleaching). The application of advanced fluorescence microscopy techniques (TIRFM, SIM, PALM, SMT) improves the spatial resolution and makes possible the study of cellular and molecular processes in bacterial cells. As part of my research activities, I lead specific developments in these different imaging modalities (sample preparation, acquisition conditions) in collaboration with Arnaud Chastanet. In parallel, I design software for automatic analysis of microscopy and data images. More generally, I provide technology watch on these new imaging modalities to identify those that can answer our biological questions.
More recently, I initiated a new research project aimed at characterizing the spatio-temporal organization of membrane microdomains and determining their impacts in cell wall biosynthesis in B. subtilis and E. coli bacteria. The study of molecular dynamics is based on two complementary methods, fluorescence correlation spectroscopy (FCS) and photobleaching fluorescence recovery (FRAP).
cyrille-billaudeau
