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See detailNormer le passé en Communauté française
Grandjean, Geoffrey ULg

Scientific conference (2015, December 03)

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See detailGovernor General of the Catholic Netherlands' confessor and Madrid's politics.
Pirlet, Pierre-François ULg

Conference (2015, December 03)

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See detailAssessing the O2 budget under sea ice: An experimental and modelling approach
Moreau, S.; Kaartokallio, H.; Vancoppenolle, M. et al

in Elementa: Science of the Anthropocene (2015), 3(000080),

The objective of this study was to assess the O2 budget in the water under sea ice combining observations and modelling. Modelling was used to discriminate between physical processes, gas-specific ... [more ▼]

The objective of this study was to assess the O2 budget in the water under sea ice combining observations and modelling. Modelling was used to discriminate between physical processes, gas-specific transport (i.e., ice-atmosphere gas fluxes and gas bubble buoyancy) and bacterial respiration (BR) and to constrain bacterial growth efficiency (BGE). A module describing the changes of the under-ice water properties, due to brine rejection and temperature-dependent BR, was implemented in the one-dimensional halo-thermodynamic sea ice model LIM1D. Our results show that BR was the dominant biogeochemical driver of O2 concentration in the water under ice (in a system without primary producers), followed by gas specific transport. The model suggests that the actual contribution of BR and gas specific transport to the change in seawater O2 concentration was 37% during ice growth and 48% during melt. BGE in the water under sea ice, as retrieved from the simulated O2 budget, was found to be between 0.4 and 0.5, which is in line with published BGE values for cold marine waters. Given the importance of BR to seawater O2 in the present study, it can be assumed that bacteria contribute substantially to organic matter consumption and gas fluxes in ice-covered polar oceans. In addition, we propose a parameterization of polar marine bacterial respiration, based on the strong temperature dependence of bacterial respiration and the high growth efficiency observed here, for further biogeochemical ocean modelling applications, such as regional or large-scale Earth System models [less ▲]

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See detailOnset of Streptomyces development: an iron fist dictatorship
Rigali, Sébastien ULg

Conference (2015, December 03)

Detailed reference viewed: 16 (1 ULg)
See detailANNUAL SCIENTIFIC REPORT - Climate change and Antarctic microbial biodiversity (CCAMBIO)
Tytgat, Bjorn; Willems, Anne; Sweetlove, Maxime et al

Report (2015)

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See detailPotentiels de la carte hydrogéologique de Wallonie : cas concrets.
Bouezmarni, Mohamed ULg; Capette, L.; Rekk, S. et al

Conference (2015, December 03)

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See detailMT4-MMP, a potential prognostic factor in triple negative breast cancer
Yip, Cassandre ULg; FOIDART, Pierre ULg; SOMJA, Joan ULg et al

Scientific conference (2015, December 03)

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See detailAFM study of the penicillin receptor BlaR1 of Bacillus licheniformis
Mescola, Andrea ULg; Dauvin, Marjorie ULg

Poster (2015, December 03)

In presence of β-lactamines, some strains of B. licheniformis secret a β-lactamase that hydrolyses the antibiotic, making the bacteria resistant to penicillin. Staphylococcus aureus possesses a very ... [more ▼]

In presence of β-lactamines, some strains of B. licheniformis secret a β-lactamase that hydrolyses the antibiotic, making the bacteria resistant to penicillin. Staphylococcus aureus possesses a very similar system, allowing the expression of a β-lactamase in response to the presence of antibiotic outside the cell . In both strains, cells are able to sense the antibiotic in the medium through a membrane penicillin receptor BlaR1. Up to now, the 3D structure addressing the receptor in its entire form is not available, mainly due to low production yields and degradation. Here we show production, purification and reconstitution of the entire membrane protein in a lipid bilayer and a first AFM study of intra-molecular forces involved in the activation process of BlaR1. [less ▲]

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See detailFunctional characterization of FRD3,  a citrate transporter, in Arabidopsis relatives
Scheepers, Maxime ULg; Charlier, Jean-Benoit; Spielmann, Julien ULg et al

Poster (2015, December 03)

Transcriptomic studies identified genes which are constitutively over-expressed in A. halleri compared to A. thaliana and which may have a role in metal tolerance or accumulation (1-3). A candidate gene ... [more ▼]

Transcriptomic studies identified genes which are constitutively over-expressed in A. halleri compared to A. thaliana and which may have a role in metal tolerance or accumulation (1-3). A candidate gene encodes FRD3, a member of the MATE family of membrane transporters (56 members in A. thaliana). It is a citrate transporter involved in iron homeostasis (4-6) and playing a role in zinc tolerance in A. thaliana (7). We are aiming to analyse the FRD3 high expression in A. halleri and the FRD3 function in zinc and iron homeostasis in A. thaliana. [less ▲]

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See detailThe return of Turkey to the Western Balkans: a challenge or an opportunity for the European Union?
Lika, Liridon ULg

in Politikon: IAPSS Journal of Political Science (2015)

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See detailDesign of a single-species biofilm reactor based on metal structured packing for the production of high added value biomolecules
Zune, Quentin ULg

Doctoral thesis (2015)

Thesis summary In the last decade, numerous single-species biofilm reactors of various configurations have been implemented at lab and pilot scale for the production of chemicals and biological products ... [more ▼]

Thesis summary In the last decade, numerous single-species biofilm reactors of various configurations have been implemented at lab and pilot scale for the production of chemicals and biological products. Compared to their counterparts in submerged cultures, these processes benefit from the specific physiology of biofilms, i.e. high robustness of the microbial system, long-term activity, continuous implementation and low ratio size / productivity. However, the risks of biofouling and the lack of analytical tools for the control and the monitoring of biofilms are obstacles for scale-up strategies. Up to now, single-species biofilm reactors have been mainly confined to the production of metabolites ranging from low (bulk chemicals) to medium (fine chemicals) added values. In this way, there is a need to design efficient single-species biofilm reactors exhibiting good scalability potentials and intended for the production of high added value compounds. In this work, an experimental single-species biofilm reactor has been designed for the production of target molecules derived from metabolic pathways involved in biofilm physiology. On the basis of these criteria, three biological models having good abilities of biofilm formation and secretion performances were selected : - the gram positive bacterium Bacillus subtilis for the production of surfactin, a surface active metabolite involved in biofilm formation. - the filamentous fungus Trichoderma reesei for the production of hydrophobin (HFBII), a surface active protein (7kDa) involved in adhesion process of spores and mycelium on solid surface. - the filamentous fungus Aspergillus oryaze (engineered strain) for the production of a recombinant protein (Gla::GFP) under the control of the glaB promoter specifically activated in solid-state fermentation. The proposed experimental biofilm reactor has the configuration of a trickle-bed bioreactor. The agitation axis of a stirred tank reactor has been removed and replaced by a stainless steel structured packing filling the top of the vessel. The liquid medium, located in the bottom of the vessel is continuously recirculated on the packing element thanks to a peristaltic pump. An ascending air flow is performed above the liquid phase just under the packing element. This thesis reports the screening of the three biological models in the experimental biofilm reactor. The results include the characterization of process performances in terms of biofilm formation and secretion of the target molecule under different operating conditions. An original methodology based on high energy X-ray tomography has been developed to non-invasively visualize and quantify the biofilm colonization inside the packing element. This technique has highlighted that biofilm colonization and liquid phase distribution across the packing are strongly interrelated phenomena. The biofilm of B. subtilis occurring by cell aggregation preferentially developed on solid areas wetted by the liquid. Accordingly, optimal operating conditions improving liquid phase distribution have been defined for biofilm colonization. The fungal biofilm of A. oryzae and T. reesei occuring by cell filamentation equally colonize submerged and aerial surfaces of the packing element. Consequently, another configuration of biofilm reactor comprising a packing element totally immersed in the liquid medium has been investigated. The production yields of surfactin and hydrophobin in the experimental biofilm reactor are respectively 1.25 and 2.64 times greater than those of a submerged culture in a stirred tank reactor. This suggests that surface-active molecules involved in biofilm formation have a real interest for the design of single-species biofilm reactors. Although the Gla::GFP fusion protein is greater produced in the stirred tank culture, its integrity was preserved in the biofilm reactor despite the presence of proteases. This suggests that the quality and the stability of heterologous proteins produced in a fungal biofilm reactor are improved compared with a submerged culture. Finally, the implementation of the biofilm reactor has led to technological progresses including low energy consumption, no foam formation, continuous processing and simplification of downstream process operations. Further experiments should deepen the understanding of structured phenotypic heterogeneity impact on secretion performances in the biofilm reactor. These experiments should consider development of operating conditions allowing for the growth of a thin biofilm homogeneously distributed on the whole surface provided by the packing element in order to optimize nutrients and metabolites mass transfers. The scale-up and the continuous implementation of the process should be also investigated. [less ▲]

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See detailRegulation of Tissue Factor by Epithelial-to-Mesenchymal Transitions: Impacts for the metastatic progression.
Francart; Bourcy, M; Suarez-Carmona, M et al

Poster (2015, December 03)

Detailed reference viewed: 10 (1 ULg)