A5033037635- Entomopathogenic Microorganisms in Pest Control
- Insect and Pesticide Research
- Insect Resistance and Genetics
- Insect symbiosis and bacterial influences
- Nematode management and characterization studies
- Insect and Arachnid Ecology and Behavior
- Insect Pest Control Strategies
- Legume Nitrogen Fixing Symbiosis
- Insect Utilization and Effects
- Plant and animal studies
- Antimicrobial Peptides and Activities
- Plant Pathogenic Bacteria Studies
- Evolution and Genetic Dynamics
- Plant Disease Resistance and Genetics
- Antibiotic Resistance in Bacteria
- Insects and Parasite Interactions
- Genomics and Phylogenetic Studies
- Microbial Metabolism and Applications
- Bacterial Genetics and Biotechnology
- Insect-Plant Interactions and Control
- Biofuel production and bioconversion
- Pharmaceutical and Antibiotic Environmental Impacts
- CRISPR and Genetic Engineering
- Bacteriophages and microbial interactions
- Plant-Microbe Interactions and Immunity
Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
2021-2025
Diversité, génomes et interactions micro-organismes-insectes
2014-2024
Université de Montpellier
2011-2023
Centre National de la Recherche Scientifique
1991-2023
Institut Agro Montpellier
1998-2013
Institut National de la Recherche Agronomique
1996-2013
Laboratoire d’Ethologie Expérimentale et Comparée
1995-1999
Université Claude Bernard Lyon 1
1991-1993
Photorhabdus luminescens is a symbiont of nematodes and broad-spectrum insect pathogen. The complete genome sequence strain TT01 5,688,987 base pairs (bp) long contains 4,839 predicted protein-coding genes. Strikingly, it encodes large number adhesins, toxins, hemolysins, proteases lipases, wide array antibiotic synthesizing These proteins are likely to play role in the elimination competitors, host colonization, invasion bioconversion cadaver, making P. promising model for study symbiosis...
In non-motile forms of Azospirillum lipoferum isolated from the rhizosphere rice, polyphenol oxidase activity was observed which correlated with production a dark-brown pigment. Using combination substrate/inhibitor specificity tests, intracellular enzyme extracts strains were clearly demonstrated to have laccase by oxidising various o- and p-diphenols. This work is first report on in Azospirillum.
Members of the genus Xenorhabdus are entomopathogenic bacteria that associate with nematodes. The nematode-bacteria pair infects and kills insects, both partners contributing to insect pathogenesis providing nutrition nematode from available insect-derived nutrients. provides protection predators, access nutrients, a mechanism dispersal. bacterial Photorhabdus also nematodes kill genera provide similar services their different hosts through unique physiological metabolic mechanisms. We...
Xenorhabdus nematophila, a member of the Enterobacteriaceae, kills many species insects by strongly depressing immune system and colonizing entire body. A peptide cytotoxin has been purified from X. nematophila broth growth, cytolytic effect on insect immunocytes hemolytic mammalian red blood cells this toxin have described (Ribeiro, C., Vignes, M., Brehélin, M. (2003) J. Biol. Chem. 278, 3030-3039). We show here that toxin, alpha-xenorhabdolysin (Xax), triggers apoptosis in both cells. also...
Summary Vibrio splendidus , strain LGP32, is an oyster pathogen associated with the summer mortalities affecting production of Crassostrea gigas oysters worldwide. LGP32 was shown to resist up 10 µM Cg ‐Def defensin and ‐BPI bactericidal permeability increasing protein, two antimicrobial peptides/proteins (AMPs) involved in C. immunity. The resistance both standard AMPs (polymyxin B, protegrin, human BPI) dependent on ompU gene. Indeed, upon inactivation, minimal concentrations decreased by...
ABSTRACT Bacteria of the genus Xenorhabdus are mutually associated with entomopathogenic nematodes Steinernema and pathogenic to a broad spectrum insects. The act as vectors, transmitting bacteria insect larvae, which die within few days infection. We characterized early stages bacterial infection in insects by constructing constitutive green fluorescent protein (GFP)-labeled nematophila strain. injected GFP-labeled into monitored found that had an extracellular life cycle hemolymph rapidly...
ABSTRACT Xenorhabdus is a major insect pathogen symbiotically associated with nematodes of the family Steinernematidae. This motile bacterium displays swarming behavior on suitable media, but spontaneous loss motility observed as part phenomenon designated phase variation which involves stationary-phase products active antibiotics and potential virulence factors. To investigate role one transcriptional activators flagellar genes, FlhDC, in virulence, nematophilus flhDC locus was identified...
Photorhabdus is an entomopathogenic bacterium belonging to the Enterobacteriaceae. The genome of TT01 strain luminescens was recently sequenced and a large number toxin-encoding genes were found. Genomic analysis predicted presence on chromosome encoding type three secretion system (TTSS), main role which delivery effector proteins directly into eukaryotic host cells. We report here functional characterization TTSS. locus identified encodes secretion/translocation apparatus, gene expression...
Photorhabdus luminescens is a symbiont of entomopathogenic nematodes. Analysis the genome sequence this organism revealed homologue PhoP-PhoQ, two-component system associated with virulence in intracellular bacterial pathogens. This was shown to respond availability environmental magnesium. A mutant knockout mutation regulatory component (phoP) had no obvious growth defect. It was, however, more motile and sensitive antimicrobial peptides than its wild-type parent. Remarkably, eliminated an...
The dlt operon encodes proteins that alanylate teichoic acids, the major components of cell walls gram-positive bacteria. This generates a net positive charge on bacterial walls, repulsing positively charged molecules and conferring resistance to animal human cationic antimicrobial peptides (AMPs) in pathogenic AMPs damage membrane are most effective humoral immune response against We investigated role insect virulence by inactivating this Bacillus cereus, which is both an opportunistic...
Bacteria have evolved sophisticated mechanisms to deliver potent toxins into bacterial competitors or eukaryotic cells in order destroy rivals and gain access a specific niche hijack essential metabolic signaling pathways the host. Delivered effectors carry various activities such as nucleases, phospholipases, peptidoglycan hydrolases, enzymes that deplete pools of NADH ATP, compromise cell division machinery, host cytoskeleton. Effectors categorized family polymorphic modular structure,...
In Gram-negative bacteria, resistance-nodulation-division-type efflux pumps, particularly AcrAB-TolC, play a critical role in mediating resistance to antimicrobial agents and toxic metabolites, contributing multidrug resistance. Photorhabdus laumondii is an entomopathogenic bacterium that has garnered significant interest due its production of bioactive specialized metabolites with anti-inflammatory, antimicrobial, scavenger deterrents properties. previous work, we demonstrated AcrAB confers...
ABSTRACT Xenorhabdus spp. and Photorhabdus are major insect bacterial pathogens symbiotically associated with nematodes. These bacteria transported by their nematode hosts into the hemocoel of prey, where they proliferate within hemolymph. In this work we report that wild strains belonging to different species both genera able produce hemolysin activity on blood agar plates. Using a hemocyte monolayer bioassay, cytolytic against immunocompetent cells from hemolymph Spodoptera littoralis...
ABSTRACT Photorhabdus is an entomopathogenic bacterium symbiotically associated with nematodes of the family Heterorhabditidae. Bacterial hemolysins found in numerous pathogenic bacteria are often virulence factors. We describe here nucleotide sequence and molecular characterization luminescens phlBA operon, a locus encoding hemolysin which shows similarities to Serratia type hemolysins. It belongs two-partner secretion (TPS) proteins. In low-iron conditions, transcriptional induction operon...
The cycle inhibiting factor (Cif) produced by enteropathogenic and enterohemorrhagic Escherichia coli was the first cyclomodulin to be identified that is injected into host cells via type III secretion machinery. Cif provokes cytopathic effects characterized G1 G2 cell arrests, accumulation of cyclin-dependent kinase inhibitors (CKIs) p21waf1/cip1 p27kip1 formation actin stress fibres. X-ray crystal structure revealed it a divergent member superfamily enzymes including cysteine proteases...
Antibiotic resistance is an increasing threat to human health. A direct link has been established between antimicrobial self-resistance determinants of antibiotic producers, environmental bacteria, and clinical pathogens. Natural odilorhabdins (ODLs) constitute a new family 10-mer linear cationic peptide antibiotics inhibiting bacterial translation by binding the 30S subunit ribosome. These bioactive secondary metabolites are produced entomopathogenic symbiont Xenorhabdus (Morganellaceae),...
Xenorhabdus spp., entomopathogenic bacteria symbiotically associated with nematodes of the family Steinernematidae, occur spontaneously in two phases. Phase I, variant naturally isolated from infective-stage nematode, provides better conditions than phase II for nematode reproduction. This study has shown that I variants displayed a swarming motility when they were grown on suitable solid medium (0.6 to 1.2% agar). Whereas most different spp. able undergo cycle rapid and coordinately...
Bacterial virulence is an integrative process that may involve quorum sensing. In this work, we compared by global expression profiling the wild-type entomopathogenic Photorhabdus luminescens subsp. laumondii TT01 to a luxS-deficient mutant unable synthesize type 2 quorum-sensing inducer AI-2. AI-2 was shown regulate more than 300 targets involved in most compartments and metabolic pathways of cell. located high hierarchy, as it controls several transcriptional regulators. The regulatory...
Abstract Background Flexible genomes facilitate bacterial evolution and are classically organized into polymorphic strain-specific segments called regions of genomic plasticity (RGPs). Using a new web tool, RGPFinder , we investigated units in genomes, by exhaustive description the RGPs two Photorhabdus Xenorhabdus strains, belonging to Enterobacteriaceae interacting with invertebrates (insects nematodes). Results account for about 60% genome each four studied. We classified islands (GIs),...