Publications of Bernard Joris
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See detailHeterotrophic growth of microalgae
Carone, Michele ULiege; Corato, Amélie ULiege; Dauvrin, Thomas ULiege et al

in Rampelotto, Pabulo H; Hallman, A (Eds.) Heterotrophic growth of microalgae (2019)

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See detailImpact of penicillin stress on peptidoglycan peptides recycling in Bacillus spp.
Dauvin, Marjorie ULiege; Delvaux, Cédric ULiege; Joris, Bernard ULiege et al

Poster (2019, September 25)

In Gram-positive bacteria, the recycling of peptides resulting from peptidoglycan (PG) degradation occurring during cell growth or penicillin stress is not yet known in details. Furthermore, in B ... [more ▼]

In Gram-positive bacteria, the recycling of peptides resulting from peptidoglycan (PG) degradation occurring during cell growth or penicillin stress is not yet known in details. Furthermore, in B. licheniformis, cytoplasmic PG peptides accumulation have been shown to be involved in penicillin resistance1. However, the mechanism that regulates this accumulation remains unknown. To shed light upon this regulation pathway, we deleted in B. subtilis 168 and B. licheniformis MW3 ykfABCD genes postulated to be involved in PG peptide recycling1. For both strains we have quantified the cytoplasmic PG peptides during cell growth in absence or in presence of β-lactam. Penicillin stress in our case is generated by the addition of cephalosporin C. On the other hand, we studied the expression of dppABCDE-ykfABCD by following the expression of yfp reporter gene under the control of Pdpp promoter. [less ▲]

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See detailNew insights to understand enterococcal ß-lactam resistance
Raymackers, Alice ULiege; Maréchal, Maxime; Verlaine, Olivier ULiege et al

Poster (2019, July)

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See detailA new insight into β-lactam resistance in enterococci
Raymackers, Alice ULiege; Verlaine, Olivier ULiege; Amoroso, Ana Maria ULiege et al

Poster (2019, February 07)

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See detailUnderstanding enterococcal β-lactam resistance
Raymackers, Alice ULiege; Verlaine, Olivier ULiege; Amoroso, Ana Maria ULiege et al

Poster (2019)

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See detailUncovering actors of enterococcal β-lactam resistance
Raymackers, Alice ULiege; Amoroso, Ana Maria ULiege; Joris, Bernard ULiege et al

Poster (2018, May 17)

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See detailStudy of the regulation of β-lactam resistance in Enterococcus hirae
Raymackers, Alice ULiege; Maréchal, Maxime; Verlaine, Olivier ULiege et al

Poster (2017, June 13)

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See detailSeparation, identification and quantification of peptidoglycan fragments by zwitterionic hydrophilic interaction chromatography and capillary electrophoresis coupled to mass spectrometry
Boulanger, Madeleine ULiege; Delvaux, Cédric ULiege; Raymackers, Alice ULiege et al

Poster (2017, June 05)

Bacterial peptidoglycan-derived muropeptides and peptides are soluble fragments acting as messengers in diverse cell-signalling events. As the peptidoglycan wall is a key target of antibiotics, bacteria ... [more ▼]

Bacterial peptidoglycan-derived muropeptides and peptides are soluble fragments acting as messengers in diverse cell-signalling events. As the peptidoglycan wall is a key target of antibiotics, bacteria have developed specific resistance mechanisms based on the detection of these fragments inside their cytoplasm. In our model strain, Bacillus licheniformis, the peptidoglycan dipeptide m-A2pm-D-Glu triggers a beta-lactamase induction. However, the nature and the concentration of cytoplasmic peptidoglycan fragments leading to the dipeptide formation are unknown. Additionally, the muropeptides sensing is involved in the innate immune response toward bacterial invasion and is therefore of considerable importance in eukaryotes self-defence functions. In this context, the development of reliable analytical methods aiming to identify and quantify those fragments in complex samples are of major interest. [less ▲]

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See detailStudy of the regulation of the operon ftsW-psr-pbp5 in Enterococcus hirae
Raymackers, Alice ULiege; Maréchal, Maxime; Verlaine, Olivier ULiege et al

Poster (2017, May 11)

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See detailDraft genome sequence of the axenic strain Phormidesmis priestleyi ULC007, a cyanobacterium isolated from Lake Bruehwiler (Larsemann Hills, Antarctica)
Lara, Yannick ULiege; Durieu, Benoit ULiege; Cornet, Luc ULiege 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 detailPeptidoglycan fragments separation and identification by zwitterionic hydrophilic interaction chromatography and capillary electrophoresis coupled to mass spectrometry
Boulanger, Madeleine ULiege; Raymackers, Alice ULiege; Delvaux, Cédric ULiege et al

Poster (2017, February 08)

Bacterial peptidoglycan-derived peptides and muropeptides are soluble unique fragments acting as messengers in diverse cell-signalling events. As the bacterial peptidoglycan wall is a major target of ... [more ▼]

Bacterial peptidoglycan-derived peptides and muropeptides are soluble unique fragments acting as messengers in diverse cell-signalling events. As the bacterial peptidoglycan wall is a major target of antibiotics, bacteria have developed specific resistance mechanisms based on the detection of such fragments. In addition, the muropeptides sensing is involved in the innate immune response toward bacterial invasion and is therefore of major importance in the eukaryotes self-defence functions. In Bacillus licheniformis 749/I, the peptidoglycan dipeptide m-A2pm-D-Glu triggers beta-lactam resistance via the induction of a beta-lactamase, BlaP. This induction process relies on a complex regulation system for which the nature and the concentration of peptidoglycan fragments leading to the formation of dipeptide moiety inside the cytoplasm are unknown. In this context, the development and the validation of a reliable method to identify and quantify those cytoplasmic fragments is of major interest. Conventionally, the peptidoglycan is first digested by mutanolysin in order to generate muropeptides which are subsequently analyzed by reversed-phase liquid chromatography (RP-LC, C18). However, this technique is not effective enough to separate the peptides that, as a result, are eluted in the flow through . In this work, we developed two novel analytical separation methods, namely capillary electrophoresis (CE) and zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC) both coupled to mass spectrometry (MS), aiming at overcoming the drawbacks encountered in traditional separation techniques. Both methods show great results in the identification of peptidoglycan fragments in complex samples. CE analysis lead to muropeptides and peptides separation whereas ZIC-HILIC only retains peptides. Nevertheless, the latter has been optimized and validated for the cytoplasmic peptidoglycan peptides identification and quantification. Althogether, ZIC-HILIC-MS and CE-MS have proved to be powerful analytical tools for the identification and quantification of peptidoglycan fragments in complex matrix samples. Further optimizations are still ongoing for the analysis of muropeptides, which hopefully will lead to the identification and quantification of cytoplasmic peptidoglycan fragments composition during the Bacillus licheniformis 749/I BlaP beta-lactamase induction process. [less ▲]

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

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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