A5020768084- Evolution and Genetic Dynamics
- Probiotics and Fermented Foods
- Escherichia coli research studies
- Bacterial Genetics and Biotechnology
- Genomics and Phylogenetic Studies
- Bacteriophages and microbial interactions
- Evolutionary Game Theory and Cooperation
- Viral gastroenteritis research and epidemiology
- Gene Regulatory Network Analysis
- Gut microbiota and health
- Microbial Metabolism and Applications
- Extracellular vesicles in disease
- Bacterial Infections and Vaccines
- Chemical Synthesis and Analysis
- Legionella and Acanthamoeba research
- Microbial Metabolites in Food Biotechnology
- Cancer Research and Treatments
- Water Treatment and Disinfection
- DNA Repair Mechanisms
- Polyamine Metabolism and Applications
- Enzyme Production and Characterization
- Genetic diversity and population structure
- Antibiotic Resistance in Bacteria
- Microbial Metabolic Engineering and Bioproduction
- Inhalation and Respiratory Drug Delivery
Université Grenoble Alpes
2010-2023
Institut polytechnique de Grenoble
2019-2023
Centre National de la Recherche Scientifique
2010-2023
VetAgro Sup
2022-2023
Translational Innovation in Medicine and Complexity
2017-2021
Université Joseph Fourier
2010-2014
Centre de Recherche en Nutrition Humaine d'Auvergne
2012
Université de Poitiers
2008
Institut National de la Recherche Agronomique
2007
Laboratoire de Biotechnologie et Chimie Marines
2005-2006
Ecological opportunities promote population divergence into coexisting lineages. However, the genetic mechanisms that enable new lineages to exploit these are poorly understood except in cases of single mutations. We examined how two Escherichia coli diverged from their common ancestor at outset a long-term coexistence. By sequencing genomes and reconstructing history one lineage, we showed three mutations together were sufficient produce frequency-dependent fitness effects allowed this...
Significance Bacterial genomes are extremely diverse in size and composition. Biologists have long sought to explain such variability based on present-day selective mutational forces. However, mutation rates can change dramatically over time, experiments with hypermutable bacteria show that their rapidly decay when propagated under the near absence of selection. Whether selection prevent this is unclear. Here, we document rapid genome even during tens thousands generations sustained...
Abstract Insertion sequences (IS) are ubiquitous bacterial mobile genetic elements, and the mutations they cause can be deleterious, neutral, or beneficial. The long-term dynamics of IS elements their effects on bacteria poorly understood, including whether primarily genomic parasites important drivers adaptation by natural selection. Here, we investigate contribution to evolution fitness during a experiment with Escherichia coli . account for ~35% that reached high frequency through 50,000...
DNA supercoiling acts as a global transcriptional regulator in bacteria, that plays an important role adapting their expression programme to environmental changes, but for which no quantitative or even qualitative regulatory model is available. Here, we focus on spatial heterogeneities caused by the transcription process itself, strongly contribute this regulation mode. We propose new mechanistic modeling of transcription-supercoiling dynamical coupling along genome, allows simulating and...
In aquatic environments, biofilms constitute an ecological niche where Legionella pneumophila persists as sessile cells. However, very little information on the mode of life L. is currently available. We report here development a model biofilm strain Lens and first transcriptome analysis Global gene expression cells compared to two distinct populations planktonic revealed that substantial proportion genes differentially expressed, 2.3 % 2932 predicted exhibited at least twofold change in...
Closely related organisms usually occupy similar ecological niches, leading to intense competition and even extinction. Such also can promote rapid phenotypic evolution divergence. This process may end with the stable occupation of distinct niches or, alternatively, entail repeated bouts evolution. Here we examine two Escherichia coli lineages, called L S, that coexisted for more than 30,000 generations after diverging from a common ancestor. Both lineages underwent sustained based on global...
The microbiota constitutes an important part of the holobiont in which extracellular vesicles (EVs) are key players health, especially regarding inter- and intra-kingdom communications. Analysis EVs from red blood cell concentrates healthy donors revealed variable amounts OmpA LPS 12 14 analyzed samples, providing indirect experimental evidence presence human circulating absence barrier disruption. To investigate role these EVs, we tracked fusion fluorescent Escherichia coli with mononuclear...
Abstract Shiga toxin (Stx) produced by enterohemorrhagic Escherichia coli (EHEC) binds to endothelial cells expressing globotriaosylceramide-3 (Gb-3) and induces cell death inhibiting translation. Nonetheless, the effects of Stx on human enterocytes, which lacks receptor Gb-3, remain less known. In this study, we questioned whether EHEC-derived may modulate cellular signalization in Gb-3-negative epithelial line T84. EHEC was fixed internalized cells. A weak activation NF-κB observed T84...
Shiga-toxin (Stx) is the cardinal virulence factor of enterohemorrhagic Escherichia coli (EHEC). The genes encoding Stx are carried by a lambdoid phage integrated in bacterial genome and fully expressed after SOS response induced DNA-damaging agents. Because nitric oxide (NO) an essential mediator innate immune infected colonic mucosa, we aimed to determine its role production EHEC. Here demonstrate that chemical or cellular sources NO inhibit spontaneous mitomycin C-induced stx mRNA...
Summary We previously characterized three Lactococcus lactis promoters, P170, P1 and P3, which are induced by low pH. Here, we identified a novel 14 bp regulatory DNA region centred at around −41.5 composed of tetranucleotide sequences, boxes A, C D. Boxes A contribute to activity, whereas box D the position ACD (renamed ACiD‐box) essential activity acid response. also trans ‐acting protein, RcfB, is involved in P170 basal for their pH induction. The regulator belongs Crp‐Fnr family...
ABSTRACT In lantibiotic lacticin 481 biosynthesis, LctT cleaves the precursor peptide and exports mature lantibiotic. Matrix-assisted laser desorption ionization-time of flight mass spectrometry revealed that a truncated form is produced in absence or after cleavage site inactivation. Production 4-fold less efficient, its specific activity about 10-fold lower.
ABSTRACT Class I bacteriocins (lantibiotics) and class II are antimicrobial peptides secreted by gram-positive bacteria. Using two lantibiotics, lacticin 481 nisin, the bacteriocin coagulin, we showed that can be detected without any purification from whole producer bacteria grown on plates matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS). When compared results MALDI-TOF-MS performed with samples cells crude supernatants liquid cultures, former led...
The phenotypic plasticity of global regulatory networks provides bacteria with rapid acclimation to a wide range environmental conditions, while genetic changes in those provide additional flexibility as evolve across long time scales. We previously identified mutations the regulator-encoding gene fis that enhanced organismal fitness during long-term evolution experiment Escherichia coli. To gain insight into effects these mutations, we produced two-dimensional protein gels strains carrying...
Transcription regulatory networks (TRNs) are of central importance for both short-term phenotypic adaptation in response to environmental fluctuations and long-term evolutionary adaptation, with global genes often being targets natural selection laboratory experiments. Here, we combined evolution experiments, whole-genome resequencing, molecular genetics investigate the driving forces, genetic constraints, mechanisms that dictate how bacteria can cope a drastic perturbation their TRNs. The...
Abstract Over millennia, life has been exposed to ionizing radiation from cosmic rays and natural radioisotopes. Biological experiments in underground laboratories have recently demonstrated that the contemporary terrestrial background impacts physiology of living organisms, yet evolutionary consequences this biological stress not investigated. Explaining mechanisms give rise results remains difficult, it speculated hereditary may be involved. Here, we used evolution standard very...
Extracellular vesicles (EVs) are critical elements of cell–cell communication. Here, we characterized the outer membrane (OMVs) released by specific clones Escherichia coli isolated from Long-Term Evolution Experiment after 50,000 generations (50K) adaptation to glucose minimal medium. Compared with their ancestor, evolved produce small OMVs but also larger ones which display variable amounts both OmpA and LPS. Tracking ancestral, fluorescently labelled revealed that they fuse ancestral-...
Abstract DNA supercoiling acts as a global transcriptional regulator in bacteria, that plays an important role adapting their expression programme to environmental changes, but for which no quantitative or even qualitative regulatory model is available. Here, we focus on spatial heterogeneities caused by the transcription process itself, strongly contribute this regulation mode. We propose new mechanistic modeling of transcription-supercoiling dynamical coupling along genome, allows...