A5037253795- Bacterial Genetics and Biotechnology
- Bacterial biofilms and quorum sensing
- Bacteriophages and microbial interactions
- Genomics and Phylogenetic Studies
- RNA and protein synthesis mechanisms
- Biochemical and Structural Characterization
- Cellular transport and secretion
- Protist diversity and phylogeny
- Microbial Community Ecology and Physiology
- Lipid Membrane Structure and Behavior
- Cell Image Analysis Techniques
- Vibrio bacteria research studies
- Bacillus and Francisella bacterial research
- Force Microscopy Techniques and Applications
- Photosynthetic Processes and Mechanisms
- Photoreceptor and optogenetics research
- Bacterial Identification and Susceptibility Testing
- Protein Structure and Dynamics
- Plant and Biological Electrophysiology Studies
- Escherichia coli research studies
- Microfluidic and Bio-sensing Technologies
- Slime Mold and Myxomycetes Research
- Image Processing Techniques and Applications
- Single-cell and spatial transcriptomics
- Micro and Nano Robotics
Laboratoire de Chimie Bactérienne
2016-2025
Aix-Marseille Université
2016-2025
Institut de Microbiologie de la Méditerranée
2016-2025
Centre National de la Recherche Scientifique
2016-2025
Living Systems (United States)
2025
University of Geneva
2023
National Institutes of Health
2023
Centre de Biologie Structurale
2021
University of California, Berkeley
2005-2014
Centre National pour la Recherche Scientifique et Technique (CNRST)
2011
The bacterium Myxococcus xanthus has two motility systems: S motility, which is powered by type IV pilus retraction, and A unknown mechanism(s). We found that involved transient adhesion complexes remained at fixed positions relative to the substratum as cells moved forward. Complexes assembled leading cell poles dispersed rear of cells. When reversed direction, A-motility clusters relocalized new together with S-motility proteins. Frz chemosensory system coordinated systems. dynamics...
Protein-directed intracellular transport has not been observed in bacteria despite the existence of dynamic protein localization and a complex cytoskeleton. However, trafficking clear potential uses for important cellular processes such as growth, development, chromosome segregation, motility. Conflicting models have proposed to explain Myxococcus xanthus motility on solid surfaces, some favoring secretion engines at rear cells others evoking an unknown class molecular motors distributed...
In the environment, bacteria compete with each other for nutrient availability or to extend their ecological niche. The type VI secretion system contributes bacterial competition by translocation of antibacterial effectors from predators into prey cells. T6SS assembles a dynamic structure-the sheath-wrapped around tube constituted Hcp protein. It has been proposed that cycling between extended and contracted conformations sheath acts as crossbow propel toward target cell. While dynamics have...
Myxococcus xanthus, a soil bacterium, predates collectively using motility to invade prey colonies. Prey lysis is mostly thought rely on secreted factors, cocktails of antibiotics and enzymes, direct contact with cells. In this study, we show that surfaces the coupling A-motility contact-dependent killing central predatory mechanism driving effective colony invasion consumption. At molecular level, involves newly discovered type IV filament-like machinery (Kil) both promotes arrest cell...
Studies of bacterial communities, biofilms and microbiomes, are multiplying due to their impact on health ecology. Live imaging microbial communities requires new tools for the robust identification cells in dense often inter-species populations, sometimes over very large scales. Here, we developed MiSiC, a general deep-learning-based 2D segmentation method that automatically segments single bacteria complex images interacting with little parameter adjustment, independent microscopy settings...
The predatory deltaproteobacterium Myxococcus xanthus uses a helically-trafficked motor at bacterial focal-adhesion (bFA) sites to power gliding motility. Using total internal reflection fluorescence and force microscopies, we identify the von Willebrand A domain-containing outer-membrane (OM) lipoprotein CglB as an essential substratum-coupling adhesin of transducer (Glt) machinery bFAs. Biochemical genetic analyses reveal that localizes cell surface independently Glt apparatus; once there,...
Cell movement on surfaces relies focal adhesion complexes (FAs), which connect cytoskeletal motors to the extracellular matrix produce traction forces. The soil bacterium Myxococcus xanthus uses a bacterial FA (bFA), for surface and predation. bFA system, known as Agl-Glt, is complex network of at least 17 proteins spanning cell envelope. Despite understanding system dynamics, its molecular structure protein interactions remain unclear. In this study, we utilize AlphaFold generate models...
Bacillus anthracis , thuringiensis and cereus are members of the group. These bacteria express virulence in diverse ways mammals insects. The pathogenic properties B. results largely from secretion non‐specific toxins, including haemolysins, production which depends upon a pleiotropic activator PlcR. In PlcR is inactive because nonsense mutation plcR gene. This suggests that phenotypic differences between on one hand other could result at least partly loss regulon. We expressed functional...
Little is known about directed motility of bacteria that move by type IV pilus-mediated (twitching) motility. Here, we found during periodic cell reversals Myxoccocus xanthus, pili were disassembled at one pole and reassembled the other pole. Accompanying these reversals, FrzS, a protein required for motility, moved in an oscillatory pattern between poles. The frequency oscillations was controlled Frz chemosensory system, which essential Pole-to-pole migration FrzS appeared to involve...
Regulated cell polarity is central to many cellular processes. We investigated the mechanisms that govern rapid switching of (reversals) during motility bacterium Myxococcus xanthus. Cellular reversals are mediated by pole-to-pole oscillations proteins and frequency under control Frz chemosensory system. However, molecular mechanism creates dynamic remained be characterized. In this work, we establish polarization regulated GTP cycle a Ras-like GTPase, MglA. initially sought an MglA...
Bacteria glide across solid surfaces by mechanisms that have remained largely mysterious despite decades of research. In the deltaproteobacterium Myxococcus xanthus, this locomotion allows formation stress-resistant fruiting bodies where sporulation takes place. However, large number genes identified as important for gliding, no specific machinery has been so far, hampering in-depth investigations. Based on premise components gliding must co-evolved and encode both envelope-spanning proteins...
In bacteria, multicellular behaviors are regulated by cell-cell signaling through the exchange of both diffusible and contact-dependent signals. a context, Myxococcus cells can share outer membrane (OM) materials an unknown mechanism involving traAB genes gliding motility. Using live imaging, we show for first time that transient contacts between two sufficient to transfer OM materials, proteins lipids, at high efficiency. Transfer was associated with formation dynamic tubes, strongly...
In biology, the extracellular matrix (ECM) promotes both cell adhesion and specific recognition, which is essential for central developmental processes in eukaryotes prokaryotes. However, live studies of dynamic interactions between cells ECM, example during motility, have been greatly impaired by imaging limitations: mostly ability to observe ECM at high resolution absence staining microscopy. To solve this problem, we developed a unique technique, wet-surface enhanced ellipsometry contrast...
In Myxococcus xanthus the gliding motility machinery is assembled at leading cell pole to form focal adhesions, translocated rearward propel cell, and disassembled lagging pole. We show that MglA, a Ras-like small G-protein, an integral part of this machinery. function, MglA stimulates assembly complex by directly connecting it MreB actin cytoskeleton. Because nucleotide state regulated spatially only binds in guanosine triphosphate–bound form, complexes are dispersed where triphosphatase...
Summary Adjustment of the synthesis abundant protein to requirements cell involves processes critical minimization energy expenditure. The regulation S‐layer genes might be a good model for such because expression must controlled, that encoded proteins exactly cover surface bacterium. Bacillus anthracis has two genes, sap and eag , encoding Sap EA1 respectively. We report production localization are under developmental control, suggesting an exponential phase ‘Sap layer’ is subsequently...
Migrating cells employ sophisticated signal transduction systems to respond their environment and polarize towards attractant sources. Bacterial also regulate polarity dynamically reverse direction of movement. In Myxococcus xanthus, a GTP-bound Ras-like G-protein, MglA, activates the motility machineries at leading cell pole. Reversals are provoked by pole-to-pole switching which is under control chemosensory-like cascade (Frz). It was previously known that asymmetric localization MglA one...