A5073982023- Antimicrobial Peptides and Activities
- Bacterial Genetics and Biotechnology
- RNA modifications and cancer
- Cancer Research and Treatments
- Pediatric health and respiratory diseases
- Immune Response and Inflammation
- Genomics and Phylogenetic Studies
- Protein Hydrolysis and Bioactive Peptides
- Glycosylation and Glycoproteins Research
- Viral gastroenteritis research and epidemiology
- Immunotherapy and Immune Responses
- Escherichia coli research studies
- RNA and protein synthesis mechanisms
- Microplastics and Plastic Pollution
- Galectins and Cancer Biology
- Digestive system and related health
- Amino Acid Enzymes and Metabolism
- Bacteriophages and microbial interactions
- Recycling and Waste Management Techniques
- Helicobacter pylori-related gastroenterology studies
- Enzyme function and inhibition
- Metal-Organic Frameworks: Synthesis and Applications
- Photodynamic Therapy Research Studies
- Bacterial biofilms and quorum sensing
- Polyamine Metabolism and Applications
Inserm
2012-2024
Institut de Biologie de l'École Normale Supérieure
2024
Centre National de la Recherche Scientifique
2024
École Normale Supérieure - PSL
2024
Université Paris Sciences et Lettres
2024
Centre d'Études Scientifiques et Techniques d'Aquitaine
2023
Institut Pasteur
2008-2018
Microbiologie de l’alimentation au service de la santé
2010
Département Génétique Animale
2005-2007
Institut National de la Recherche Agronomique
2004-2007
Antimicrobial factors are efficient defense components of the innate immunity, playing a crucial role in intestinal homeostasis and protection against pathogens. In this study, we report that upon infection polarized human cells vitro, virulent Shigella flexneri suppress transcription several genes encoding antimicrobial cationic peptides, particularly β-defensin hBD-3, which show to be especially active S. flexneri. This is an example targeted survival strategy. We also identify MxiE...
The enteropathogen Shigella flexneri invades epithelial cells, leading to inflammation and tissue destruction. We report that infection of cells induces an early genotoxic stress, but the resulting p53 response cell death are impaired due bacterium's ability promote degradation, mainly through calpain protease activation. Calpain activation is promoted by virulence effector VirA dependent on calcium flux depletion endogenous inhibitor calpastatin. Further, although VirA-induced activity...
CodY, a pleiotropic transcriptional regulator conserved in low G+C species of Gram-positive bacteria, was previously described to be the central proteolysis Lactococcus lactis . In this study, over 100 potential CodY targets were identified by DNA-microarray analysis. Complementary analysis experiments carried out validate newly defined regulon. Moreover, direct role regulation several target genes demonstrated gel retardation experiments. Interestingly, 45 % CodY-dependent encode enzymes...
Adhesion of Helicobacter pylori to the gastric mucosa is a necessary prerequisite for pathogenesis H. pylori–related diseases. In this study, we investigated GalNAcβ1-4GlcNAc motif (also known as N,N'-diacetyllactosediamine [lacdiNAc]) carried by MUC5AC mucins target bacterial binding human mucosa. The expression LacdiNAc was correlated with localization, and all strains tested adhered significantly motif. Proteomic analysis mutant construction allowed identification yet uncharacterized...
Significance Antimicrobial peptides exert antimicrobial, antifungal, antiviral, and antiprotozoan activity. They are expressed at high concentrations the intestinal mucosal surface, where they play a crucial role in homeostasis. Therefore, approaches aiming to boost expression of antimicrobial represent future therapeutic strategy treat infections dysbiosis-driven diseases humans time increasing incidence antibiotic resistance.
Summary CodY is a pleiotropic transcriptional regulator conserved in low‐G+C Gram‐positive bacteria. Two distinct signals have been shown independently to influence the activity of this regulator: level intracellular GTP Bacillus subtilis and branched‐chain amino acids (BCAA) isoleucine, leucine valine Lactococcus lactis. Measurement BCAA levels several environmental conditions showed that L. lactis responded concentrations but not physiological fluctuations GTP. In addition, we demonstrated...
Antimicrobial peptides (AMPs) are mucosal defense effectors of the human innate immune response. In intestine, AMPs produced and secreted by epithelial cells to protect host against pathogens support homeostasis with commensals. The inducible nature suggests that potent inducers could be used increase their endogenous expression for prevention or treatment diseases. Here we aimed at identifying molecules from natural pharmacopoeia induce β-defensin-3 (HBD3), one most efficient AMPs, without...
Cysteine and methionine availability influences many processes in the cell. In bacteria, transcription of specific genes involved synthesis these two amino acids is usually regulated by different mechanisms or regulators. Pathways for cysteine their interconversion were experimentally determined Lactococcus lactis, a lactic acid bacterium commonly found food. A new gene, yhcE, was shown to be recycling cysteine. Surprisingly, 18 genes, representing almost all pathways, are under control...
The ppk gene of Streptomyces lividans encodes an enzyme catalyzing, in vitro, the reversible polymerization gamma phosphate ATP into polyphosphate and was previously shown to play a negative role control antibiotic biosynthesis (H. Chouayekh M. J. Virolle, Mol. Microbiol. 43:919-930, 2002). In present work, some regulatory features expression were established content S. TK24 mutant determined. Pi sufficiency, be low but detectable. DNA gel shift experiments suggested that might controlled by...
ABSTRACT MetR (formerly Smu.1225), a regulator of the LysR family, controls key genes for methionine supply in Streptococcus mutans . An S. metR mutant is unable to transport l -methionine and grow absence this amino acid. Accordingly, activates transcription by binding promoter regions two gene clusters smu.1487, whose products are involved biosynthesis (MetEF Smu.1487) uptake (AtmBDE). Transcriptional activation requires presence 17-bp palindromic sequence, Met box. Base substitutions box...
Mucin glycoproteins are secreted in large amounts by the intestinal epithelium and constitute an efficient component of innate immune defenses to promote homeostasis protect against enteric pathogens. In this study, our objective was investigate how bacterial enteropathogen Shigella flexneri, which causes bacillary dysentery, copes with mucin defense barrier. We report that upon vitro infection mucin-producing polarized human epithelial cells, virulent S. flexneri manipulates secretion...
The human β-defensin-1 (HBD1) is an antimicrobial peptide constitutively expressed by epithelial cells at mucosal surfaces. In addition to its microbicidal properties, the loss of HBD1 expression in several cancers suggests that it may also have anti-tumor activity. Here, we investigated link between and cancer signaling pathways colon cell lines TC7 HT-29, normal colonic primary cells, using a mini-gut organoid model. Using available datasets from patient cohorts, found transcription...
Abstract The Tara Microplastics mission was conducted for 7 months to investigate plastic pollution along nine major rivers in Europe—Thames, Elbe, Rhine, Seine, Loire, Garonne, Ebro, Rhone, and Tiber. An extensive suite of sampling protocols applied at four five sites on each river a salinity gradient from the sea outer estuary downstream upstream first heavily populated city. Biophysicochemical parameters including salinity, temperature, irradiance, particulate matter, large small...
ABSTRACT The genome of Streptococcus mutans encodes 4 LysR-type transcriptional regulators (LTTRs), three which, MetR, CysR ( cys teine synthesis r egulator), and HomR hom ocysteine are phylogenetically related. MetR was previously shown to control methionine metabolic gene expression. Functional analysis carried out by phenotypical studies analysis. is required activate the transcription cysK encoding cysteine biosynthesis enzyme, tcyABC gshT genes glutathione transporter systems, homR ....
The human intestinal tract is colonized with microorganisms, which present a diverse array of immunological challenges. A number antimicrobial mechanisms have evolved to cope these key defense mechanism the expression inducible peptides (AMPs), such as beta-defensins, rapidly inactivate microorganisms. We currently limited knowledge regulating AMP genes, especially factors from host required in regulatory mechanisms. To identify for beta-defensin-2 gene (HBD2) epithelial cells upon bacterial...