A5039517309- Calcium Carbonate Crystallization and Inhibition
- Marine Bivalve and Aquaculture Studies
- Aquatic Ecosystems and Phytoplankton Dynamics
- Mass Spectrometry Techniques and Applications
- Marine Biology and Environmental Chemistry
- Antibiotic Resistance in Bacteria
- Paleontology and Stratigraphy of Fossils
- Aquatic Invertebrate Ecology and Behavior
- Environmental Toxicology and Ecotoxicology
- Advanced Proteomics Techniques and Applications
- Marine and coastal ecosystems
- Pneumonia and Respiratory Infections
- Bone Tissue Engineering Materials
- Peptidase Inhibition and Analysis
- Cephalopods and Marine Biology
- Ion-surface interactions and analysis
- Geology and Paleoclimatology Research
- Marine Biology and Ecology Research
- Pneumocystis jirovecii pneumonia detection and treatment
- Analytical chemistry methods development
- Identification and Quantification in Food
- Antimicrobial Resistance in Staphylococcus
- Forensic Anthropology and Bioarchaeology Studies
- Biocrusts and Microbial Ecology
- Marine Toxins and Detection Methods
Centre National de la Recherche Scientifique
2015-2025
Molécules de Communication et Adaptation des Micro-organismes
2016-2025
Structure et Instabilité des Génomes
2012-2023
Centre de recherche en paléontologie - Paris
2023
Muséum national d'Histoire naturelle
2016-2021
Délégation Paris 6
2021
Sorbonne Université
2000-2020
Biologie des Organismes et Écosystèmes Aquatiques
2016
Institut de Recherche pour le Développement
2016
Musée de l'Homme
2006-2014
Our understanding of the mechanisms used by Mycobacterium tuberculosis to persist in a "dormant" state is essential development therapies effective sterilizing tissues. Gene expression profiling model systems has revealed complex adaptive response thought endow M. with capacity survive several months combinatorial antibiotic treatment. We show here that this may involve remodeling peptidoglycan network substitution 4-->3 cross-links generated D,D-transpeptidase activity penicillin-binding...
Three active-site cysteine L,D-transpeptidases can individually anchor the Braun lipoprotein to Escherichia coli peptidoglycan. We show here that two additional enzymes of same family form peptide bonds between third residues peptidoglycan stems, generating meso-DAP(3)-->meso-DAP(3) unusual cross-links. This activity partially replaces D,D-transpeptidase penicillin-binding proteins.
The L,D-transpeptidase Ldt(fm) catalyzes peptidoglycan cross-linking in beta-lactam-resistant mutant strains of Enterococcus faecium. Here, we show that Escherichia coli homologues are responsible for the attachment Braun lipoprotein to murein, indicating evolutionarily related domains have been tailored use muropeptides or proteins as acyl acceptors L,D-transpeptidation reaction.
The structure of Mycobacterium tuberculosis peptidoglycan is atypical since it contains a majority 3→3 cross-links synthesized by l,d-transpeptidases that replace 4→3 formed the d,d-transpeptidase activity classical penicillin-binding proteins. Carbapenems inactivate these l,d-transpeptidases, and meropenem combined with clavulanic acid bactericidal against extensively drug-resistant M. tuberculosis. Here, we used mass spectrometry stopped-flow fluorimetry to investigate kinetics mechanisms...
ABSTRACT The Mycobacterium tuberculosis peptidoglycan is cross-linked mainly by l , d -transpeptidases (LDTs), which are efficiently inactivated a single β-lactam class, the carbapenems. Development of carbapenems for treatment has recently raised considerable interest since these drugs, in association with β-lactamase inhibitor clavulanic acid, uniformly active against extensively drug-resistant M. and kill both exponentially growing dormant forms bacilli. We have purified five...
The formation of the molluscan shell is regulated to a large extent by matrix extracellular macromolecules that are secreted forming tissue, mantle. This so called "calcifying matrix" complex mixture proteins and glycoproteins assembled occluded within mineral phase during calcification process. While importance calcifying has long been appreciated, most its protein components remain uncharacterised.Recent expressed sequence tag (EST) investigations mantle tissue from tropical abalone...
Bivalves have evolved a range of complex shell forming mechanisms that are reflected by their incredible diversity in mineralogy and microstructures. A suite proteins exported to the matrix space plays significant role controlling these features, addition underpinning some physical properties itself. Although, there is general consensus minimum basic protein tool kit required for construction, date, this remains undefined. In study, (SMPs) four highly divergent bivalves (The Pacific oyster,...
ABSTRACT Few therapeutic alternatives remain for the treatment of infections due to multiresistant Mycobacterium abscessus . Here we show that peptidoglycans “rough” and “smooth” morphotypes contain predominantly 3→3 cross-links generated by l , d -transpeptidases, indicating these enzymes are attractive targets development efficient drugs.
The formation of the molluscan shell nacre is regulated to a large extent by matrix extracellular macromolecules that are secreted shell-forming tissue, mantle. This so-called ‘calcifying matrix’ complex mixture proteins, glycoproteins and polysaccharides assembled occluded within mineral phase during calcification process. Better molecular-level characterization substances regulate still required. Notable advances in expressed tag sequencing freshwater mussels, such as Elliptio complanata...
Cyanobacteria are photosynthetic prokaryotes capable of synthetizing a large diversity secondary metabolites exhibiting noticeable bioactivity or genuine toxicity. Microcystis constitutes one the most common cyanobacteria taxa forming intensive blooms that nowadays arise worldwide in freshwater ecosystems. They can produce numerous cyanotoxins (i.e. toxic cyanobacterial metabolites), which could be harmful to human health and aquatic organisms. To better understand variations production...
We report here the first direct assessment of specificity a class peptidoglycan cross-linking enzymes, l,d-transpeptidases, for highly diverse structure precursors Gram-positive bacteria. The lone functionally characterized member this new family active site cysteine peptidases, Ldtfm from Enterococcus faecium, was previously shown to bypass d,d-transpeptidase activity classical penicillin-binding proteins leading high level cross-resistance glycopeptide and β-lactam antibiotics. homologues...
In mollusks, one of the most widely studied shell textures is nacre, lustrous aragonitic layer that constitutes internal components shells several bivalves, a few gastropods,and cephalopod: nautilus. Nacre contains minor organic fraction, which displays wide range functions in relation to biomineralization process. Here, we have biochemically characterized nacre matrix cephalopod Nautilus macromphalus. The acid-soluble mixture polydisperse and discrete proteins glycoproteins, interact with...
Active-site serine D,D-transpeptidases belonging to the penicillin-binding protein family (PBPs) have been considered for a long time as essential peptidoglycan cross-linking in all bacteria. However, bypass of PBPs by an L,D-transpeptidase (Ldtfm) conveys high-level resistance β-lactams penam class Enterococcus faecium with minimal inhibitory concentration (MIC) ampicillin >2,000 µg/ml. Unexpectedly, Ldtfm does not confer carbapenem (imipenem MIC = 0.5 µg/ml) whereas cephems display...
Cyanobacterial blooms often occur in freshwater lakes and constitute a potential health risk to human populations, as well other organisms. However, their overall specific implications for the of aquatic organisms that are chronically environmentally exposed cyanobacteria producing hepatotoxins, such microcystins (MCs), together with bioactive compounds have still not been clearly established remain difficult assess. The medaka fish was chosen experimental model studying cellular molecular...
Abstract Sexual dimorphism describes the features that discriminate between two sexes at various biological levels. Especially, during reproductive phase, liver is one of most sexually dimorphic organs, because different metabolic demands sexes. The a key organ plays fundamental roles in physiological processes, including digestion, energetic metabolism, xenobiotic detoxification, biosynthesis serum proteins and also endocrine or immune response. sex-dimorphism particularly obvious oviparous...
Characterization of synthetic polymers by Matrix assisted laser desorption (MALDI) is limited the solubility different oligomers in a suitable solvent, and fingerprint mass spectrum affected properties solvents employed (eg., pH, secondary solvents, evaporation) during sample target preparation. If are not used preparation, then solvent should play an important role determining quality MALDI spectrum. We report here two solventless approaches for It was observed that Poly(ethylene glycol)...
Secondary metabolites (SMs) play key roles in pathogen responses, although knowledge of their precise functions is limited by insufficient characterization spatial response. The present study addressed this issue Arabidopsis leaves non-targeted and targeted metabolite profiling Pseudomonas syringae pv. tomato (Pst-AvrRpm1) infected adjacent uninfected leaf tissues. While overlap was observed between areas, the profiles these regions differed quantitatively clustering analysis underscores a...
ABSTRACT Peptidoglycan is polymerized by monofunctional d , -transpeptidases belonging to class B penicillin-binding proteins (PBPs) and glycosyltransferases bifunctional enzymes that combine both activities (class A PBPs). Three genes encoding putative PBPs ( pbpF, pbpZ ponA ) were deleted from the chromosome of Enterococcus faecium D344R in all possible combinations order identify cooperate with low-affinity Pbp5 for synthesis peptidoglycan presence β-lactam antibiotics. The viability...