A5068533304- Bacterial Infections and Vaccines
- Gut microbiota and health
- Clostridium difficile and Clostridium perfringens research
- Probiotics and Fermented Foods
- Extracellular vesicles in disease
- Bacterial Genetics and Biotechnology
- Bacteriophages and microbial interactions
- RNA and protein synthesis mechanisms
- Microbial Metabolites in Food Biotechnology
- Antibiotic Resistance in Bacteria
- Glycosylation and Glycoproteins Research
- Acute Lymphoblastic Leukemia research
- Cystic Fibrosis Research Advances
- Enzyme Production and Characterization
- Escherichia coli research studies
- Peptidase Inhibition and Analysis
- Adolescent and Pediatric Healthcare
- Pneumonia and Respiratory Infections
- Genomics and Phylogenetic Studies
- Infective Endocarditis Diagnosis and Management
- Gastrointestinal motility and disorders
- Acute Myeloid Leukemia Research
- Complement system in diseases
- Porphyrin Metabolism and Disorders
- Vector-borne infectious diseases
Quadram Institute
2014-2024
Norwich Research Park
2004-2022
Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement
2002
Département Génétique Animale
1999
Gram-negative bacteria ubiquitously produce and release nano-size, non-replicative outer membrane vesicles (OMVs). In the gastrointestinal (GI-) tract, OMVs generated by members of intestinal microbiota are believed to contribute maintaining microbial ecosystem mediating bacteria-host interactions, including delivery bacterial effector molecules host cells modulate their physiology. Bacterial have also been found in bloodstream although origin fate unclear. Here we investigated interactions...
Abstract Background Bacteroides thetaiotaomicron (Bt) is a prominent member of the human intestinal microbiota that, like all gram-negative bacteria, naturally generates nanosized outer membrane vesicles (OMVs) which bud off from cell surface. Importantly, OMVs can cross epithelial barrier to mediate microbe-host crosstalk involving both and immune cells help maintain homeostasis. Here, we have examined interaction between Bt blood or colonic mucosa-derived dendritic (DC) healthy individuals...
To identify β-lactamase genes in gut commensal Bacteroides species and to assess the impact of these enzymes, when carried by outer membrane vesicles (OMVs), protecting enteric pathogens commensals.A deletion mutant putative class A gene (locus tag BT_4507) found genome human thetaiotaomicron was constructed a phenotypic analysis performed. phylogenetic tree built from an alignment nine cephalosporinase protein sequences, using maximum likelihood method. The rate cefotaxime degradation after...
ABSTRACT Gram‐negative bacteria naturally produce and secrete nanosized outer membrane vesicles (OMVs). In the human gastrointestinal tract, OMVs produced by commensal can mediate interactions amongst host cells (including between epithelial immune cells) maintain microbial homeostasis. This OMV‐mediated pathway for host‐microbe could be exploited to deliver biologically active proteins body. To test this we engineered bacterium Bacteroides thetaiotaomicron (Bt), a prominent member of...
Dietary InsP6 can modulate eukaryotic cell proliferation and has complex nutritive consequences, but its metabolism in the mammalian gastrointestinal tract is poorly understood. Therefore, we performed phylogenetic analyses of microbiome order to search for candidate phosphatases. We determined that prominent gut bacteria express homologs phosphatase (MINPP) characterized enzyme from Bacteroides thetaiotaomicron (BtMinpp). show BtMinpp exceptionally high catalytic activity, which rationalize...
Abstract The gastrointestinal (GI) tract harbours a complex microbial community, which contributes to its homeostasis. A disrupted microbiome can cause GI‐related diseases, including inflammatory bowel disease (IBD), therefore identifying host‐microbe interactions is crucial for better understanding gut health. Bacterial extracellular vesicles (BEVs), released into the lumen, cross mucus layer and access underlying immune cells. To study BEV‐host interactions, we examined influence of BEVs...
Background and aims As the importance of gut–brain interactions increases, understanding how specific gut microbes interact with enteric nervous system (ENS), which is first point neuronal exposure becomes critical. Our aim was to understand dominant human bacterium Bacteroides thetaiotaomicron (Bt) regulates anatomical functional characteristics ENS.Methods Neuronal cell populations, as well enteroendocrine cells, were assessed in proximal colonic sections using fluorescent...
Bacterial extracellular vesicles (BEVs) produced by gut commensal bacteria have been proposed to play an important role in maintaining host homeostasis via interactions with the immune system. Details of mediators and pathways BEV-immune cell are however incomplete. In this study, we provide evidence for anti-inflammatory immunomodulatory properties prominent human bacterium Bacteroides thetaiotaomicron (Bt BEVs) identify molecular mechanisms underlying their interaction innate cells. mice...
The interactions between the gut microbiota and its host are of central importance to health host. Outer membrane vesicles produced ubiquitously by Gram-negative bacteria including commensal Bacteroides thetaiotaomicron. These can interact with in various ways but until now their complement small molecules has not been investigated this context. Using an untargeted high-coverage metabolomic approach we have measured molecule content these contrasting vitro conditions establish what role...
Gut microbes have critical roles in maintaining host physiology, but their effects on epithelial chemosensory enteroendocrine cells (EEC) remain unclear. We investigated the role that ubiquitous commensal gut bacterium Bacteriodes thetaiotaomicron (Bt) and its major fermentation products, acetate, propionate, succinate (APS) shaping EEC networks murine gastrointestinal tract (GIT). The distribution numbers of populations were assessed tissues along GIT by fluorescent immunohistochemistry...
Bacterial extracellular vesicles (BEVs) produced by members of the intestinal microbiota can contribute not only to digestion but also mediate microbe-host cell communication via transfer functional biomolecules mammalian host cells. An unresolved question is what factors and conditions influence BEV cargoes how do they impact on function? To address this question, we analysed compared proteome BEVs released major human gastrointestinal tract (GIT) symbiont Bacteroides thetaiotaomicron (Bt)...
Abstract Plague caused by the Gram-negative bacterium, Yersinia pestis, is still endemic in parts of world today. Protection against pneumonic plague essential to prevent development and spread epidemics. Despite this, there are currently no licensed vaccines western world. Here we describe means delivering biologically active vaccine antigens directly mucosal sites infection using highly stable microvesicles (outer membrane vesicles; OMVs) that naturally produced abundant harmless human...
The gastrointestinal tract (GIT) harbors a complex community of microbes termed the microbiota that plays role in maintaining host’s health and wellbeing. How this comes about nature microbe-host cell interactions GIT is still unclear.
The gastrointestinal tract harbors the gut microbiota, structural alterations of which (dysbiosis) are linked with an increase in permeability ("leaky gut"), enabling luminal antigens and bacterial products such as nanosized extracellular vesicles (BEVs) to access circulatory system. Blood-derived BEVs contain various cargoes may be useful biomarkers for diagnosis monitoring disease status relapse conditions inflammatory bowel (IBD). To progress this concept, we developed a rapid,...
Lactococcus lactis is the most used species in dairy industry. Its ability to adapt technological stresses, such as oxidative stress encountered during stirring first stages of cheese-making process, a key factor measure its performance. This study aimed understand response subsp. cremoris MG1363 at transcriptional and metabolic levels relation acidification kinetics growth conditions, especially an early stage growth. For those purposes, conditions hyper-oxygenation were initially fixed for...
There is considerable interest in studying the function of Bacteroides species resident human gastrointestinal (GI)-tract and contribution they make to host health. Reverse genetics protein expression techniques, such as those developed for well-characterised Escherichia coli cannot be applied other members Bacteriodetes phylum have unique promoter structures. The availability useful Bacteroides-specific genetic tools therefore limited. Here we describe development an effective...
Overexpression of the lactococcal CsiA protein affects cell wall integrity growing cells and leads to leakage intracellular material. This property was optimized exploited for targeted release biologically active compounds into extracellular environment, thereby providing a new delivery system bacterial proteins peptides. The effects different levels expression on endogenous lactate dehydrogenase nucleic acids were measured related impact Lactococcus lactis viability growth. A phenotype...
The Lactobacillus sakei 23K chromosome was analysed by pulsed-field gel electrophoresis after digestion with the restriction enzymes AscI, NotI and SfiI. size estimated to be 1845+/-80 kb. use of I-CeuI, specific for rrn genes encoding 23S rRNAs, showed that seven loci were present, on 40% chromosome. clusters mapped their orientation determined, allowing position replication origin estimated. Partial I-CeuI digestions used construct a backbone different fragments obtained SfiI assembled...
The ptsH and ptsI genes of Lactobacillus sake, encoding the general enzymes phosphoenolpyruvate: carbohydrate phosphotransferase system (PTS), were cloned sequenced. HPr (88 amino acids), encoded by ptsH, enzyme I (574 ptsI, are homologous to corresponding known other bacteria. Nucleotide sequence mRNA analysis showed that two cotranscribed in a large transcript both I. transcription ptsHI was shown be independent carbon source. Four mutants constructed single-crossover recombination. For...
Abstract The processes by which bacteria proactively scavenge essential nutrients in crowded environments such as the gastrointestinal tract are not fully understood. In this context, we observed that bacterial extracellular vesicles (BEVs) produced human commensal gut microbe Bacteroides thetaiotaomicron contain multiple high‐affinity vitamin B 12 binding proteins suggesting play a role micronutrient scavenging. Vitamin belongs to cobamide family of cofactors regulate microbial communities...
ABSTRACT Downstream from the ptsHI operon of Lactobacillus sakei , genes atkY and atkB organized in an operon, were observed. The two putative proteins, AtkB AtkY, show sequence similarity to Enterococcus hirae copper P-type ATPase, responsible for efflux, its negative regulator. Characterization as a ATPase could not be demonstrated since mutant did any phenotype. Thus, another strategy was followed order investigate transcriptional regulation atkYB locus, leading development new genetic...
CluA is a 136 kDa surface-bound protein encoded by the chromosomally located sex factor of Lactococcus lactis MG1363 and associated with cell aggregation linked to high-frequency transfer factor. To further investigate involvement in these phenomena, cluA gene was cloned on plasmid, downstream from lactococcal nisA promoter. In sex-factor-negative derivative, nisin-controlled expression resulted aggregation, despite absence other genes Therefore, only component responsible for aggregation....