References of "Joris, Bernard"
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See detailDraft Genome of the Axenic Strain Phormidesmis priestleyi ULC007, a Cyanobacterium Isolated from Lake Bruehwiler (Larsemann Hills, Antarctica)
Lara, Yannick ULg; Durieu, Benoit ULg; Cornet, Luc ULg et al

in Genome Announcements (2017)

Phormidesmis priestleyi ULC007 is an Antarctic freshwater cyanobacte- rium. Its draft genome is 5,684,389 bp long. It contains a total of 5,604 protein- encoding genes, of which 22.2% have no clear ... [more ▼]

Phormidesmis priestleyi ULC007 is an Antarctic freshwater cyanobacte- rium. Its draft genome is 5,684,389 bp long. It contains a total of 5,604 protein- encoding genes, of which 22.2% have no clear homologues in known genomes. To date, this draft genome is the first one ever determined for an axenic cyanobacterium from Antarctica. [less ▲]

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See detailCellular stress and β-lactamase BlaP induction in Bacillus licheniformis
Dauvin, Marjorie ULg; Joris, Bernard ULg

Poster (2017, February 01)

In presence of β-lactam antibiotic in its environment, B. licheniformis produces the β-lactamase BlaP, an enzyme hydrolyzing β-lactam antibiotic, conferring on the bacteria phenotypic resistance. To ... [more ▼]

In presence of β-lactam antibiotic in its environment, B. licheniformis produces the β-lactamase BlaP, an enzyme hydrolyzing β-lactam antibiotic, conferring on the bacteria phenotypic resistance. To induce BlaP, two conditions must be fulfilled. The first one is the acylation of the membrane receptor BlaR1 by the antibiotic. The second one is a cellular stress due to the presence of the antibiotic which acylate PBP1. The nature of this signal remains unknown. In this study we postulate that the extracytoplasmic function sigma factors (ECFs) σM and σX act together with the stringent response as a secondary and redundant layer of stress upon which the BlaP induction pathway relies. [less ▲]

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See detailModelling of the β-lactamase BlaP induction in Bacillus licheniformis
Dauvin, Marjorie ULg; Raymackers, Alice ULg; Delvigne, Frank ULg et al

Poster (2016, May 24)

In bacteria, the production of a β-lactamase, an hydrolase specific to β-lactam antibiotics, may be constitutive or inducible. In Bacillus licheniformis 749/I the presence of a β-lactam in the external ... [more ▼]

In bacteria, the production of a β-lactamase, an hydrolase specific to β-lactam antibiotics, may be constitutive or inducible. In Bacillus licheniformis 749/I the presence of a β-lactam in the external media is detected by a protein relay producing an intracellular signal which leads to the induction of BlaP β-lactamase expression. The blaP gene is included in a divergeon along with blaI, coding for a cytoplasmic repressor, and blaR1, coding for a penicillin membrane receptor. Both, the acylation of the extracellular domain of BlaR1 by a β-lactam together with cellular stress due to the presence of the antibiotic outside the cell generate a dipeptide (coactivator) resulting from the peptidoglycan turnover that destabilizes BlaI repressor-DNA complex, leading to the expression of β-lactam resistance. [less ▲]

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See detailPeptidoglycan fragments separation by CE/LC-MS
Boulanger, Madeleine ULg; Delvaux, Cédric ULg; Far, Johann ULg et al

Poster (2016, May 24)

In Bacillus licheniformis 749/I, the induction of BlaP beta-lactamase relies on a complex regulation system. During this process, the intracellular repressor BlaI is inactivated by a dipeptide coming from ... [more ▼]

In Bacillus licheniformis 749/I, the induction of BlaP beta-lactamase relies on a complex regulation system. During this process, the intracellular repressor BlaI is inactivated by a dipeptide coming from the peptidoglycan (PG) degradation via an “AND Gate” regulation. This regulation involves the cellular stress induced by the beta-lactam, the membrane receptor BlaR1 and the PG turnover. Briefly, the induction occurs when the extracellular domain of BlaR1 is acylated by the antibiotic which leads to a reorganization of the transmembrane segments and the receptor autocleavage. Simultaneously, the beta-lactam partially inhibits the penicillin-binding protein 1 (PBP1), triggering increased PG turnover and accumulation of PG fragments. Some of these fragments could enter in the cytoplasm and undergo enzymatic degradations which lead to the formation of the pro co-activator (tripeptide L-Ala-D-Glu-m-A2pm). This pro co-activator generates the co-activator, the dipeptide D-Glu-m-A2pm. Nowadays the nature and the concentration of PG fragments inside the cytoplasm are unknown. Therefore, the development of different analytical methods is required in order to identify those cytoplasmic fragments. In this poster, three different ways to separate PG fragments are discussed. [less ▲]

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See detailDevelopment of solid-supported methodology for the preparation of peptidoglycan fragments containing (2S,6R)-diaminopimelic acid
Simon, Justine ULg; Lamborelle, Nicolas ULg; Zervosen, Astrid et al

in Tetrahedron Letters (2016)

Herein, we describe the development of an efficient solid-supported methodology for the stereoselective synthesis of two peptides containing (2S,6R)-diaminopimelic acid, (S)-Ala-γ-(R)-Glu-(2S,6R)-A2pm-(R ... [more ▼]

Herein, we describe the development of an efficient solid-supported methodology for the stereoselective synthesis of two peptides containing (2S,6R)-diaminopimelic acid, (S)-Ala-γ-(R)-Glu-(2S,6R)-A2pm-(R)-Ala 1 and γ-(R)-Glu-(2S,6R)-A2pm 2. The platform consists of a Wang resin anchored by an amino acid chain including allylglycine. By olefin cross metathesis with vinylglycine, unsaturated protected (2S,6R)-A2pm was fixed on solid support. Peptides were achieved by cleavage of cross metathesis products from resin, followed by reduction of double bonds along removing of protecting groups. Furthermore, this efficient solid phase approach will lead to peptide and muropeptide libraries. [less ▲]

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See detailA lysine cluster in domain II of Bacillus subtilis PBP4a plays a role in the membrane attachment of this C1-PBP
Vanden Broeck, Arnaud; Van Der Heiden, Edwige ULg; Sauvage, Eric ULg et al

in PLoS ONE (2015)

In PBP4a, a Bacillus subtilis class-C1 penicillin-binding protein (PBP), four clustered lysine (K) residues, K86, K114, K119, and K265, protrude from domain II. Replacement of these amino acids with ... [more ▼]

In PBP4a, a Bacillus subtilis class-C1 penicillin-binding protein (PBP), four clustered lysine (K) residues, K86, K114, K119, and K265, protrude from domain II. Replacement of these amino acids with glutamine (Q) residues by site-directed mutagenesis yielded Mut4KQ PBP4a. When produced in Escherichia coli without its predicted Sec-signal peptide, wildtype (WT) PBP4a was found mainly associated with the host cytoplasmic membrane, whereas Mut4KQ PBP4a remained largely unbound. After purification, the capacities of the two proteins to bind to B. subtilis membranes were compared. The results were similar to those obtained in E. coli: in vitro, a much higher percentage of WT PBP4a than of Mut4KQ PBP4a was found to interact with B. subtilis membranes. Immunodetection of PBP4a in B. subtilis membrane extracts revealed that a processed form of this PBP (as indicated by its size) associates with the B. subtilis cytoplasmic membrane. In the absence of any amphiphilic peptide in PBP4a, the crown of positive charges on the surface of domain II is likely responsible for the cellular localization of this PBP and its attachment to the cytoplasmic membrane. [less ▲]

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See detailFate of the coactivator in the induction of BlaP β-lactamase in Bacillus licheniformis 749/I
Dauvin, Marjorie ULg; Amoroso, Ana Maria ULg; Joris, Bernard ULg

Poster (2015, June 23)

In bacteria, the production of a β-lactamase, an hydrolase specific to β-lactam antibiotics, may be constitutive or inducible. In Bacillus licheniformis 749/I the presence of a β-lactam in the external ... [more ▼]

In bacteria, the production of a β-lactamase, an hydrolase specific to β-lactam antibiotics, may be constitutive or inducible. In Bacillus licheniformis 749/I the presence of a β-lactam in the external media is detected by a protein relay producing an intracellular signal which leads to the induction of BlaP β-lactamase expression. The blaP gene is included in a divergeon along with blaI, coding for a cytoplasmic repressor, and blaR1, coding for a penicillin membrane receptor. Both, the acylation of the extracellular domain of BlaR1 by a β-lactam together with cellular stress due to the presence of the antibiotic outside the cell generate a dipeptide (coactivator) resulting from the peptidoglycan turnover that destabilizes BlaI repressor-DNA complex, leading to the expression of β-lactam resistance. [less ▲]

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See detailModeling β-lactamase induction in Bacillus licheniformis 749/I
Dauvin, Marjorie ULg; Vandamme, François; Abujahrur, Nora et al

Poster (2015, May 13)

The intensive use of antibiotics in infectious diseases treatment has result in selection of resistance mechanisms among bacteria. The main one is the production of a β-lactamase that hydrolyzes the β ... [more ▼]

The intensive use of antibiotics in infectious diseases treatment has result in selection of resistance mechanisms among bacteria. The main one is the production of a β-lactamase that hydrolyzes the β-lactam ring of β-lactamines. β-lactamase could be expressed constitutively or in response to the presence of β-lactam antibiotic outside the cell. From the four β-lactamase induction mechanisms known so far, the ones from Gram positive S. aureus and B. licheniformis 749/i are very closed. Its induction system includes the divergeon blaP-blaI-blaR1 and an unrelated blaR2 gene still not identified. Recent results from our lab indicate that for the induction of β-lactamase two conditions must be fulfilled. The first one is a cellular stress due to the presence of the antibiotic outside, acylating PBP1, which triggers an increase of cell wall degradation. The second one is the acylation of the membrane receptor BlaR1 by the antibiotic, which results in the derepression of the β-lactamase gene blaP by the repressor BlaI. Amoroso et al. had showed that a fragment coming from peptidoglycan degradation interact with BlaI. In the same study, they propose that this fragment would be the result of the activity of proteins encoded by ykf operon. The aim of this project is the modeling of the β–lactamase induction mechanism in B. licheniformis 749/I. [less ▲]

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See detail5′-Methylene-triazole-substituted-aminoribosyl uridines as MraY inhibitors: synthesis, biological evaluation and molecular modeling
Fer, Michael; Bouhss,, Ahmed B; Patrão, Mariana et al

in Organic & Biomolecular Chemistry (2015), 13(26), 7193

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See detailBiosensor based on optical fibers
Lismont, Marjorie ULg; Vandewalle, Nicolas ULg; Joris, Bernard ULg et al

Poster (2015, May)

Medical diagnosis and biotechnology progresses are strongly dependent on the development of sensing devices, which, ideally, would allow the reliable detection of very low amounts of biological species in ... [more ▼]

Medical diagnosis and biotechnology progresses are strongly dependent on the development of sensing devices, which, ideally, would allow the reliable detection of very low amounts of biological species in various environments. In addition to these requirements, the detection tools would also be easy to use and would rapidly response. Fluorescent based biosensors fulfil most of these characteristics. In our work, the intersection between two crossed optical fibers is used as the basic unit of an original optical biosensor. As illustrated by figure 1, one optical fiber is used to carry probe molecules and excite fluorescence while the second one is devoted to carry the target species and collect the optical signal arising from the species interacting at the node. The advantages of our set-up over traditional optical sensors are no surface functionalization, use of low amounts of biological species, limitation of the denaturation risk, ease to use and low detection threshold. The developed biosensor is validated on two systems. The first one is a fluorescent calcium indicator, Oregon green 488 BAPTA-2, whose optical emission signal is affected by Ca2+ ions concentration. The second one is based on Rh-Con A and FITC-Dextran complex for which the FRET phenomenon is affected by glucose concentration. In both cases, the results are in agreement with the ones obtained in cuvettes attesting the efficiency of the sensing device. We also show a prototype of a multichannel device composed of multiple crossed optical fibers which are used as species and light carriers. [less ▲]

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See detailGenome-wide transcriptional analysis suggests hydrogenase- and nitrogenase-mediated hydrogen production in Clostridium butyricum CWBI 1009
Calusinska, Magda; Hamilton, Christopher; Monsieurs, Pieter et al

in Biotechnology for Biofuels (2015), 8(27), 1-16

Background: Molecular hydrogen, given its pollution-free combustion, has great potential to replace fossil fuels in future transportation and energy production. However, current industrial hydrogen ... [more ▼]

Background: Molecular hydrogen, given its pollution-free combustion, has great potential to replace fossil fuels in future transportation and energy production. However, current industrial hydrogen production processes, such as steam reforming of methane, contribute significantly to the greenhouse effect. Therefore alternative methods, in particular the use of fermentative microorganisms, have attracted scientific interest in recent years. However the low overall yield obtained is a major challenge in biological H2 production. Thus, a thorough and detailed understanding of the relationships between genome content, gene expression patterns, pathway utilisation and metabolite synthesis is required to optimise the yield of biohydrogen production pathways. Results: In this study transcriptomic and proteomic analyses of the hydrogen-producing bacterium Clostridium butyricum CWBI 1009 were carried out to provide a biomolecular overview of the changes that occur when the metabolism shifts to H2 production. The growth, H2-production, and glucose-fermentation profiles were monitored in 20 L batch bioreactors under unregulated-pH and fixed-pH conditions (pH 7.3 and 5.2). Conspicuous differences were observed in the bioreactor performances and cellular metabolisms for all the tested metabolites, and they were pH dependent. During unregulated-pH glucose fermentation increased H2 production was associated with concurrent strong up-regulation of the nitrogenase coding genes. However, no such concurrent up-regulation of the [FeFe] hydrogenase genes was observed. During the fixed pH 5.2 fermentation, by contrast, the expression levels for the [FeFe] hydrogenase coding genes were higher than during the unregulated-pH fermentation, while the nitrogenase transcripts were less abundant. The overall results suggest, for the first time, that environmental factors may determine whether H2 production in C. butyricum CWBI 1009 is mediated by the hydrogenases and/or the nitrogenase. Conclusions: This work, contributing to the field of dark fermentative hydrogen production, provides a multidisciplinary approach for the investigation of the processes involved in the molecular H2 metabolism of clostridia. In addition, it lays the groundwork for further optimisation of biohydrogen production pathways based on genetic engineering techniques. [less ▲]

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See detailStructure predictions of membrane domains of proteins from the Divisome and BlaR
Crowet, Jean-Marc ULg; Dony, Nicolas; Joris, Bernard ULg et al

Poster (2014, November 28)

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See detailStereoselective synthesis of peptidoglycan fragments on solid support
Simon, Justine ULg; Lamborelle, Nicolas ULg; Joris, Bernard ULg et al

Poster (2014, June)

The mammalian proteins, Nod1 and Nod2, are able to recognize peptidoglycan motifs during bacterial infection. Interestingly, Nod1 is a detector of peptides and muropeptides containing the meso-2,6 ... [more ▼]

The mammalian proteins, Nod1 and Nod2, are able to recognize peptidoglycan motifs during bacterial infection. Interestingly, Nod1 is a detector of peptides and muropeptides containing the meso-2,6-diaminopimelic acid (m-A2pm), a non-proteinogenic amino acid found in Gram- bacteria. In this work, we describe a synthesis of peptidoglycan motifs entirely on solid support. Solid-Phase Peptide Synthesis (SPPS), Cross Metathesis (CM) and sugar chemistry are three methods to anchor respectively amino acids, m-A2pm and sugars derivatives on a resin as solid support. [less ▲]

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See detailStudies of the Domains II and III of Bacillus subtilis PBP4a in relation with the protein localization
Vanden Broeck, Arnaud ULg; Van Der Heiden, Edwige ULg; Sauvage, Eric ULg et al

Poster (2014, April 23)

Bacillus subtilis PBP4a belongs to the class-C1 PBPs characterized by two internal additional domains of unknown function. Seven lysine residues (K) are protruding from domain II. Four of them have been ... [more ▼]

Bacillus subtilis PBP4a belongs to the class-C1 PBPs characterized by two internal additional domains of unknown function. Seven lysine residues (K) are protruding from domain II. Four of them have been mutated in glutamine residues (Q). Both proteins (WT and Mut4KQ PBP4a) have been produced without signal peptide in E. coli and their sub-cellular localizations determined by measuring the DD-carboxypeptidase activities in the different compartments (cytoplasmic vs membrane attached proteins). In order to detect a possible influence of the PBP4a domain III in the localization of the protein, its encoding sequence has been cloned into pET-28b-BlaP, a vector allowing the production of WT BlaP β-lactamase or BlaP/DIII chimeric protein (with domain III inserted in a permissive loop of BlaP). The nitrocefin hydrolysis activities of BlaP or BlaP/DIII have been measured in the different cellular compartments. [less ▲]

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See detailMicrofluidic on optical fibers: Towards a new kind of fluorescent biosensor
Lismont, Marjorie ULg; Vandewalle, Nicolas ULg; Weyer, Floriane ULg et al

Poster (2014, February)

In recent works, the behavior of droplets moving along vertical treads due to gravity was studied. It appeared that the droplet can be stopped by encountering a horizontal fiber depending on droplet ... [more ▼]

In recent works, the behavior of droplets moving along vertical treads due to gravity was studied. It appeared that the droplet can be stopped by encountering a horizontal fiber depending on droplet volumes and fiber characteristics. On the basis of this behavior and by replacing treads by two crossed optical fibers, it is possible to combine fluidics and optics to develop a new kind of fluorescent sensor. In our work, the intersection between two crossed optical fibers is used as the basic unit of an original optofluidic biosensor. These two optical fibers are used as droplets carriers: one for probe molecules and the other one for target species. The fiber's junction catches the droplets and act as a reaction center. The main advantage of using optical fibers resides in their ability to propagate and collect light to and from the droplet localized at the fiber's crossing. This optical fiber configuration can therefore allow the study of biological interactions using fluorescent labels. This new and versatile detection scheme was validated on a calcium indicator where ions detection is accomplished by using a dye, Oregon green Bapta-2, that has a Ca 2+ recognition group as well as an entity exhibiting fluorescence. A FRET recognition event, between Rh-Con A and FITC-Dextran, was also investigated to detect glucose. Finally, a prototype of a multiplexing device, composed of several juxtaposed fibers' junctions, was developed. [less ▲]

Detailed reference viewed: 144 (30 ULg)