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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).

[24] Juillot D, Cornilleau C, Deboosere N, Billaudeau C, Evouna-Mengue P, Lejard V, Brodin P, Carballido-López R, Chastanet A. A High-Content Microscopy Screening Identifies New Genes Involved in Cell Width Control in Bacillus subtilis. mSystems. 2021 Nov 30;6(6):e0101721. doi: 10.1128/mSystems.01017-21.

[23] Labarde A, Jakutyte L, Billaudeau C, Fauler B, López-Sanz M, Ponien P, Jacquet E, Mielke T, Ayora S, Carballido-López R, Tavares P. 
Temporal compartmentalization of viral infection in bacterial cells. Proc Natl Acad Sci U S A. 2021 Jul 13;118(28):e2018297118. doi: 10.1073/pnas.2018297118.

[22] Hamouche L, Billaudeau C, Rocca A, Chastanet A, Ngo S, Laalami S, Putzer H.
Dynamic Membrane Localization of RNase Y in Bacillus subtilis. mBio. 2020 Feb 18;11(1):e03337-19. doi: 10.1128/mBio.03337-19.

[21] Billaudeau C, Chastanet A, Carballido-López R.
Processing TIRF Microscopy Images to Characterize the Dynamics and Morphology of Bacterial Actin-Like Assemblies. Methods Mol Biol. 2020 Jan; 2101:135-145. doi: 10.1007/978-1-0716-0219-5_9.

[20] Cornilleau C, Chastanet A, Billaudeau C, Carballido-López R.
Methods for Studying Membrane-Associated Bacterial Cytoskeleton Proteins In Vivo by TIRF Microscopy. Methods Mol Biol. 2020 Jan; 2101:123-133. doi: 10.1007/978-1-0716-0219-5_8.

[19] Billaudeau C, Yao Z, Cornilleau C, Carballido-Lopez R, Chastanet A.
MreB Forms Subdiffraction Nanofilaments during Active Growth in Bacillus subtilis. MBio. 2019 Jan 29; doi: 10.1128/mBio.01879-18.

[18] Xia F, Qian CR, Xun Z, Hamon Y, Sartre AM, Formisano A, Mailfert S, Phelipot MC, Billaudeau C, Jaeger S, Nunès JA, Guo XJ, He HT.
TCR and CD28 Concomitant Stimulation Elicits a Distinctive Calcium Response in Naive T Cells. Front Immunol. 2018 Dec 4;9:2864. doi: 10.3389/fimmu.2018.02864. eCollection 2018.

[17] Chouaki-Benmansour N, Ruminski K, Sartre AM, Phelipot MC, Salles A, Bergot E, Wu A, Chicanne G, Fallet M, Brustlein S, Billaudeau C, Formisano A, Mailfert S, Payrastre B, Marguet D, Brasselet S, Hamon Y, He HT.
Phosphoinositides regulate the TCR/CD3 complex membrane dynamics and activation, Sci Rep., vol 8, pp. 4966, Mar 21 (2018)

[16] Billaudeau C*, Chastanet A*, Yao Z*, Cornilleau C, Mirouze N, Fromion V, Carballido-López R.
Contrasting mechanisms of growth in two model rod-shaped bacteria., Nature Communications, vol 8, pp. 15370, Jun 7. (2017)

[15] Frick M, Mouchacca P, Verdeil G, Hamon Y, Billaudeau C, Buferne M, Fallet M, Auphan-Anezin N, Schmitt-Verhulst AM, Boyer C.
Distinct patterns of cytolytic T-cell activation by different tumour cells revealed by Ca2+ signalling and granule mobilization, Immunology, vol 150, pp. 199 (2017)

[14] Guidi M, Ruault M, Marbouty M, Loïodice I, Cournac A, Billaudeau C, Hocher A, Mozziconacci J, Koszul R & Taddei A
Spatial reorganization of telomeres in long-lived quiescent cells, Genome Biology, vol. 16, pp. 206 (2015)

[13] Salles A*, Billaudeau C*, Sergé A, Bernard A-M, Phelipot M, Bertaux N, Fallet M, Grenot P, Marguet D, Hé H-T & Hamon Y
Barcoding T Cell Calcium Response Diversity with Methods for Automated and Accurate Analysis of Cell Signals, PloS Computational Biology, 9, e1003245 (2013)

[12] Billaudeau C, Mailfert S, Trombik T, Bertaux N, Rouger V, Hamon Y, He H-T & Marguet D
Probing the plasma membrane organization in living cells by spot variation fluorescence correlation spectroscopy, in "Fluorescence Fluctuation Spectroscopy" edited by Tetin S © 2013 Methods in Enzymology, vol 519, pp. 277 (2013)

[11] Rouger V, Billaudeau C, Mailfert S, Trombik T, Hamon Y, He H-T, Marguet D
Chapter "Deciphering the cell membrane organization by fluorescence correlation spectroscopy at different length scales", in "Properties and Functions of Biological Membranes Investigated by Fluorescence Methods” edited by Mely Y & Duportail G © 2012 Springer Series of Fluorescence, vol 13, pp. 271 (2013)

[10] Rouger V, Bertaux N, Trombik T, Mailfert S, Billaudeau C, Marguet D, Sergé A
Mapping Molecular Diffusion in the Plasma Membrane by Multiple-Target Tracing, Journal of Visualized Experiments, vol. 63, e3599 (2012)

[9] Brustlein S, Ferrand P, Walther N, Brasselet S, Rigneault H, Billaudeau C & Marguet D
Optical parametric oscillator-based light source for coherent Raman scattering microscopy: practical overview, Journal of Biomedical Optics, vol. 16, pp. 021106 (2011)

[8] Brustlein S, Berto P, Hostein R, Ferrand P, Billaudeau C, Marguet D, Muir A, Knight J & Rigneault R
Double-clad hollow core photonic crystal fiber for coherent Raman endoscope, Optics Express, vol. 19, pp. 12562-12568 (2011)

[7] Billaudeau C, Collin S, Pardo F, Bardou N & Pelouard J-L
Tailoring radiative and non-radiative losses of thin nanostructured plasmonic waveguides, Optics Express, 17, 3490 (2009)

[6] Collin S, Sauvan C, Billaudeau C, Pardo F, Rodier JC, Pelouard J-L & Lalanne P
Surface modes on nanostructured metallic surfaces, Physical Review B, vol. 79, pp. 165405 (2009)

[5] Billaudeau C, Collin S, Pardo F, Bardou N & Pelouard J-L
Towards tunable light propagation and emission in thin nanostructured plasmonic waveguides, Applied Physics Letters, 92, 041111 (2008)

[4] Sauvan C, Billaudeau C, Collin S, Bardou N, Pardo F, Pelouard J-L & Lalanne P
Surface plasmon coupling on metallic film perforated by two-dimensional rectangular hole array, Applied Physics Letters, 92, 011125 (2008)

[3] Billaudeau C, Collin S, Sauvan C, Bardou N, Pardo F & J-L. Pelouard
Angle-resolved transmission measurements through anisotropic 2D plasmonic crystals, Optics Letters, 33, 165 (2008)

[2] Vincent G, Billaudeau C, Collin S, Haïdar R, Madouri A, Chouteau D, Laroche M, Guérineau N, Pardo F & Pelouard J-L
Drilled dielectric membranes for highly resonant filtering in the infrared, Proc. of SPIE, vol. 6591, pp. 659107 (2007)

[1] Chaumet P & Billaudeau C
Coupled dipole method to compute optical torque: application to a micropropeller, Journal of Applied Physics, vol. 101, pp. 023106 (2007)

2004-2007 Ph. D in nanophotonics, Paris-Sud 11 University, Orsay, France. Thesis entitled "Waveguiding in 1D and 2D plasmonic crystals"
2003-2004 Master's degree in research "Optics and Image Processing", École Nationale Supérieure de Physique de Marseille (ENSPM, Aix-Marseille III University).          
2001-2004 Engineering school, ENSPM.