A5053231700- Bacterial biofilms and quorum sensing
- Antimicrobial Resistance in Staphylococcus
- Bacterial Genetics and Biotechnology
- Bacteriophages and microbial interactions
- RNA and protein synthesis mechanisms
- Biochemical and Structural Characterization
- Listeria monocytogenes in Food Safety
- Streptococcal Infections and Treatments
- Probiotics and Fermented Foods
- Neutrophil, Myeloperoxidase and Oxidative Mechanisms
- Biopolymer Synthesis and Applications
- Metalloenzymes and iron-sulfur proteins
- Antimicrobial Peptides and Activities
- Microbial Metabolism and Applications
- Plant nutrient uptake and metabolism
- Iron Metabolism and Disorders
- Plant biochemistry and biosynthesis
- Chromium effects and bioremediation
- Phytase and its Applications
- Tuberculosis Research and Epidemiology
- Microbial Inactivation Methods
- Trace Elements in Health
- Metal Extraction and Bioleaching
- Enzyme Catalysis and Immobilization
- Cytomegalovirus and herpesvirus research
Université Paris Cité
2000-2025
Centre National de la Recherche Scientifique
2010-2025
Institut Pasteur
2010-2025
Zero to Three
2003
Institut Jacques Monod
2000-2002
Sorbonne Université
2000-2002
The highly conserved WalK/WalR (also known as YycG/YycF) two-component system is specific to low-G+C gram-positive bacteria. While this essential for cell viability, both the nature of its regulon and physiological role have remained mostly uncharacterized. We observed that, unexpectedly, Staphylococcus aureus death induced by WalKR depletion was not followed lysis. show that positively controls autolytic activity, in particular two major S. autolysins, AtlA LytM. By using our previously...
The YycG/YycF essential two-component system (TCS), originally identified in Bacillus subtilis, is very highly conserved and appears to be specific low-G+C gram-positive bacteria, including several pathogens such as Staphylococcus aureus. By studying growth of S. aureus cells where the yyc operon controlled by an isopropyl-beta-D-thiogalactopyranoside (IPTG)-inducible promoter, we have shown that this during at 37 degrees C starvation for regulatory leads cell death. During a previous study...
The WalKR two-component system is essential for the viability of Staphylococcus aureus, playing a central role in controlling cell wall metabolism. We produced constitutively active form WalR S. aureus through phosphomimetic amino acid replacement (WalR(c), D55E). strain displayed significantly increased biofilm formation and alpha-hemolytic activity. Transcriptome analysis was used to determine full extent regulon, revealing positive regulation major virulence genes involved host matrix...
ABSTRACT In Escherichia coli , the expression of sodB which encodes iron superoxide dismutase, has been suggested to be activated by Fur, iron-responsive global regulator initially characterized as a transcriptional repressor. We investigated regulation functional analysis promoter using sodB-lac fusions with various truncated and mutated promoters. Several cis - trans -acting elements involved in have identified. The β-galactosidase activity sodB-lacZ reporter RNA showed sevenfold...
Summary The YycG/YycF two‐component system, originally identified in Bacillus subtilis , is very highly conserved and appears to be specific low G + C Gram‐positive bacteria. This system required for cell viability, although the basis this nature of YycF regulon remained elusive. Using a combined hybrid regulator/transcriptome approach involving inducible expression PhoP′‐′YycF chimerical protein B . we have shown that yocH which encodes potential autolysin, specifically activated by YycF....
The WalKR two-component system is essential for viability of Staphylococcus aureus, a major pathogen. We have shown that acts as the master controller peptidoglycan metabolism, yet none identified regulon genes explain its requirement cell viability. Transmission electron micrographs revealed wall thickening and aberrant division septa in absence WalKR, suggesting may be linked to role coordinating metabolism division. therefore tested whether uncoupling autolysin gene expression from...
The food-borne pathogen Listeria monocytogenes is adapted to a diversity of environments, such as soil, food, body fluids, and the cytosol eukaryotic cells. transition between saprophytic pathogenic life mediated through complex regulatory pathways that modulate expression virulence factors. Here we examined inlJ, recently identified gene encoding protein LPXTG-internalin family involved in pathogenesis. We show inlJ controlled neither by major listerial regulator genes, PrfA, nor AxyR,...
The Gram-positive intracellular pathogen Listeria monocytogenes is endowed with 17 sets of genes encoding two-component systems. L. closely related to the model bacterium Bacillus subtilis, in which we have shown previously that DegS/DegU system plays a central role controlling stationary phase adaptive responses, including degradative enzyme synthesis and competence. Although an orthologue DegU response regulator present monocytogenes, gene cognate DegS kinase conspicuously absent. We...
Mobile genetic elements play an essential part in the infectious process of major pathogens, yet role prophage dynamics Staphylococcus aureus remains poorly understood. Here we studied impact φ13 hlb-converting prophage, whose integration inactivates hlb β-toxin gene, on staphylococcal pathogenesis. We showed that is lost approximately half bacterial population during course infection. Inactivation int recombinase for insertion/excision, locked chromosome, leading to a significant loss...
Transfer RNA molecules have been recently recognized as widespread targets of bacterial immune systems. Translation inhibition through tRNA cleavage or modification inhibits phage propagation, thereby protecting the population. To counteract this, some viruses encode their own molecules, allowing infection to take place. The AriB effector PARIS defence system is a Toprim nuclease previously shown target E. coli tRNALys(UUU), but not tRNALys(UUU) variant encoded by bacteriophage T5. We...
Summary Two‐component signal transduction systems (TCS) are an important mechanism by which bacteria sense and respond to their environment. Although each two‐component system appears detect a specific signal(s), it is now evident that they do not always act independently of other. In this paper we present data indicating regulatory links between the PhoPR participates in cellular response phosphate limitation, essential YycFG Bacillus subtilis . We show PhoR sensor kinase can activate YycF...
The success of Staphylococcus aureus, as both a human and animal pathogen, stems from its ability to rapidly adapt wide spectrum environmental conditions. Two-component systems (TCSs) play crucial role in this process. Here, we describe novel staphylococcal virulence factor, SpdC, an Abi-domain protein, involved signal sensing and/or transduction. We have uncovered functional link between the WalKR essential TCS SpdC Abi membrane protein. Expression spdC is positively regulated by system...
Fur (ferric uptake regulation protein) activates sodB expression, increasing expression levels by a factor of seven and transcript stability three. Post-transcriptional was investigated searching for endoribonucleases that might be involved in mRNA degradation. The activation significantly reduced if both the RNaseE RNaseIII genes were mutated. This correlated with cleavage at palindromic sequence located 5′ untranslated region transcript. An RNA-binding assay showed did not directly protect...
Summary DegU is considered to be an orphan response regulator in Listeria monocytogenes since the gene encoding cognate histidine kinase DegS absent from genome. We have previously shown that involved motility, chemotaxis and biofilm formation contributes L. virulence. Here, we investigated role of phosphorylation Bacillus subtilis can phosphorylate vitro . introduced B. degS into , showed this leads highly increased expression motility genes, a DegU‐dependent fashion. inactivated predicted...
We have characterized a novel pleiotropic role for CymR, the master regulator of cysteine metabolism. show here that CymR plays an important both in stress response and virulence Staphylococcus aureus. Genes involved detoxification processes, including oxidative metal ion homeostasis, were differentially expressed ΔcymR mutant. Deletion cymR resulted increased sensitivity to hydrogen peroxide-, disulfide-, tellurite- copper-induced stresses. Estimation metabolite pools suggests this...
When Bacillus subtilis is subjected to phosphate starvation, the Pho regulon activated by PhoP-PhoR two-component signal transduction system elicit specific responses this nutrient limitation. The response regulator, PhoP, and its cognate histidine sensor kinase, PhoR, are encoded phoPR operon that transcribed as a 2.7-kb bicistronic mRNA. from two sigma(A)-dependent promoters, P(1) P(2). Under conditions where was not induced (i.e., phosphate-replete or phoR-null mutant), low level of...
Several Bacillus strains secrete phytase, an enzyme catalyzing dephosphorylation of myo-inositol hexakisphosphate (phytate). We identified the phyC (phytase) gene from environmental amyloliquefaciens FZB45 as a member phosphate starvation-inducible PhoPR regulon. In vivo and in vitro assays revealed that PhoP approximately P is essential for transcription. The transcriptional start site was downstream sigmaA-like promoter region located 27 bp upstream probable translation ATG codon....
The molecular triggers leading to virulence of a number human-adapted commensal bacteria such as Streptococcus gallolyticus are largely unknown. This opportunistic pathogen is responsible for endocarditis in the elderly and associated with colorectal cancer. Colonization damaged host tissues exposed collagen, cardiac valves pre-cancerous polyps, mediated by appendages referred Pil1 pili. Populations S. heterogeneous majority cells weakly piliated while smaller fraction hyper piliated. We...