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A chimeric Mla-Pqi lipid transport system is required for Brucella abortus survival in macrophages
Get PDFThe cell envelope of gram-negative bacteria is composed of an inner and an outer membrane. In Escherichia coli, several pathways mediate phospholipid transport between the two membranes, including the Mla (i.e., maintenance of lipid asymmetry) and Pqi (i.e., paraquat inducible) systems. Here, we identify and characterise in the intracellular pathogen Brucella abortus a complex named Mpc, which exhibits homology to both Mla and Pqi components. Mpc is required for bacterial growth under envelope stress conditions, and for survival within macrophages during the early stages of infection. Analyses of protein-protein interactions and structural predictions suggest that the Mpc complex bridges the two membranes of the bacterial cell envelope. Absence of this system results in altered lipid composition of the outer membrane vesicles, indicating that Mpc plays a role in lipid transport between the membranes. Our sequence comparisons reveal that Mpc is conserved across numerous species of Hyphomicrobiales. The discovery of this novel lipid-trafficking system expands our understanding of the diversity and evolution of lipid-transport mechanisms in diderm bacteria.</p
Accompagner les élèves dans l’appropriation de la langue de l’école à l’aide de dispositifs flexibles et transversaux:Recherche en éducation n° 192/24 - Rapport final année 1
No full textNovel Janus XGa-PbP (X = S, Se) monolayers:excellent photocatalysts for overall water splitting
Get PDFThe search for efficient and sustainable materials for solar-driven water splitting has intensified with the emergence of two-dimensional (2D) Janus structures. In this work, we theoretically design and explore two novel Janus monolayers, SGa-PbP and SeGa-PbP, using first-principles calculations. Our results reveal that both monolayers are dynamically, thermally, and mechanically stable, and exhibit direct band gaps (0.93 eV for SGa-PbP and 1.24 eV for SeGa-PbP) ideally suited for visible-light absorption. Impressively, these systems display strong optical absorption in the visible and ultraviolet regions, with absorption coefficients reaching 105 cm−1. The asymmetric structure induces built-in electric fields that enhance charge separation, while the PbP surface provides active hydrogen adsorption sites with nearly optimal free energy |ΔGH*| values for hydrogen evolution. Most notably, the corrected solar-to-hydrogen conversion efficiencies reach 40.69% and 31.75% for SGa-PbP and SeGa-PbP, respectively-significantly surpassing many state-of-the-art 2D photocatalysts. These findings position XGa-PbP Janus monolayers as highly promising candidates for next-generation solar hydrogen production technologies.</p
Simultaneous protection of the marine environment and critical infrastructures:a dual challenge for State action at sea. The Belgian example
Get PDFThis article is based on the contribution presented by the author in Marseille on March 25, 2025, during the First Conference of European Marine Academies. It provides an overview of current Belgian legislation on the protection of marine areas and highlights the role of these areas as critical infrastructures within the geopolitical context
Trapped by trails:How different types of recreational trails influence seasonal space use of wildlife in a densely visited national park
No full textProtected areas face the challenge of balancing conservation goals with increasing recreational use, which can strongly influence behavioural changes of wildlife and, consequently, affect ecosystem functioning. Understanding the impacts of various recreational activities on wildlife behaviour is essential for guiding targeted management strategies and supporting sustainable conservation practices. In the 60 km2, highly visited Hoge Kempen National Park (Belgium), we assessed habitat preferences and the seasonal impact of hiking, mountain biking, and tarmac cycling trail densities on the land use of roe deer, wild boar, and red fox. From May 2018 until May 2019, camera traps were used to monitor wildlife. Since individual animals could not be uniquely identified and the detection is imperfect, we used N-mixture models to estimate spatial variation in their land use, given their detection probability. We revealed species-specific seasonal differences in the impact of recreational trails and habitats. From all recreational trail types, hiking had the most negative impact on land use of roe deer and wild boar, while the impact of cycling and mountain biking trails was only negative in Spring. Furthermore, hiking and cycling trails had a more negative impact on land use of roe deer during the day than at night. In contrast, red fox selected areas with high recreational trail density in multiple seasons. These findings underscore the difference and seasonality in the impact of various recreation types on wildlife land use, highlighting the need for recreation monitoring and adaptive management strategies to mitigate or leverage recreational pressures on wildlife.</p
À la rencontre des médiévistes en Belgique… Entretien avec Alain Dierkens (Université libre de Bruxelles)
Get PDFIonic liquid-grafted MXene composite polymer electrolytes for high-performance solid-state batteries
No full textAll-solid-state batteries (ASSBs) have obtained much attention due to the high energy density and security. At present, PEO-based solid-state batteries are considered to be one of the most promising candidates for high-performance ASSBs due to the excellent processability and good interfacial stability. However, low ionic conductivity and Li+ transference number seriously hinder their progress in practical applications. Here, a novel filler is developed by embedding ionic liquid (IL) grafted onto the surface of MXene to improve the electrochemical performance of PEO-based solid composite polymer electrolyte (MXene-IL-SPE) for ASSBs. The 2D MXene can significantly reduce the crystallinity of PEO, and the presence of IL not only enhances the dispersion of MXene in the polymer matrix, but also promotes the dissociation of lithium salts and anchors anions. As a result, the MXene-IL-SPE possesses high ionic conductivity (7.19 × 10−4 S cm−1) and Li+ transference number (0.51), together with wide electrochemical window (5.2 V) at 60 °C. The assembled LiFePO4|MXene-IL-SPE|Li full cell exhibits remarkable rate capability and exceptional capacity of 154.8 mAh g−1 over 120 cycles with an impressive 95.3 % capacity retention at 0.5 C. This design opens up a new way to prepare high performance CPEs for ASSBs.</p
