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See detailClass A β -Lactamases as Versatile Scaffolds to Create Hybrid Enzymes: Applications from Basic Research to Medicine
Huynen, Céline ULg; Filée, Patrice; Matagne, André ULg et al

in BioMed Research International (2013), 2013

Designing hybrid proteins is a major aspect of protein engineering and covers a very wide range of applications frombasic research to medical applications. This review focuses on the use of class A 𝛽 ... [more ▼]

Designing hybrid proteins is a major aspect of protein engineering and covers a very wide range of applications frombasic research to medical applications. This review focuses on the use of class A 𝛽-lactamases as versatile scaffolds to design hybrid enzymes (referred to as 𝛽-lactamase hybrid proteins, BHPs) in which an exogenous peptide, protein or fragment thereof is inserted at various permissive positions.We discuss how BHPs can be specifically designed to create bifunctional proteins, to produce and to characterize proteins that are otherwise difficult to express, to determine the epitope of specific antibodies, to generate antibodies against nonimmunogenic epitopes, and to better understand the structure/function relationship of proteins. [less ▲]

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See detailLa class action à la belge est arrivée
Boularbah, Hakim ULg

in Justement (2014)

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See detailClass II histone deacetylases: versatile regulators.
Verdin, Eric; Dequiedt, Franck ULg; Kasler, Herbert G

in Trends in Genetics (2003), 19(5), 286-93

Histone acetylation and deacetylation play essential roles in modifying chromatin structure and regulating gene expression in eukaryotes. Histone deacetylases (HDACs) catalyze the deacetylation of lysine ... [more ▼]

Histone acetylation and deacetylation play essential roles in modifying chromatin structure and regulating gene expression in eukaryotes. Histone deacetylases (HDACs) catalyze the deacetylation of lysine residues in the histone N-terminal tails and are found in large multiprotein complexes with transcriptional co-repressors. Human HDACs are grouped into three classes based on their similarity to known yeast factors: class I HDACs are similar to the yeast transcriptional repressor yRPD3, class II HDACs to yHDA1 and class III HDACs to ySIR2. In this review, we focus on the biology of class II HDACs. These newly discovered enzymes have been implicated as global regulators of gene expression during cell differentiation and development. We discuss their emerging biological functions and the molecular mechanisms by which they are regulated. [less ▲]

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See detailThe class IIa HDACs prevent degradation of RBFOX2 by Chaperone-Mediated Autophagy
Detiffe, Cécile ULg; Dequiedt, Franck ULg; Rambout, Xavier ULg

Poster (2015, June)

By modulating the acetylation level of histones, histone deacetylases (HDACs) are enzymes playing a key role in the control of gene expression. In addition to histones, HDACs also have non-histone ... [more ▼]

By modulating the acetylation level of histones, histone deacetylases (HDACs) are enzymes playing a key role in the control of gene expression. In addition to histones, HDACs also have non-histone substrates, which may relate to potential roles for HDACs outside of gene regulation. Because HDACs are key regulators of major cellular processes such as cell division, apoptosis and differentiation, it is not surprising that these enzymes have emerged as attractive therapeutic targets for cancer. While the in vivo antitumoral activities of several small molecules HDACs inhibitors have generated a lot of hope, these molecules often showed dramatic side-effects. It is suspected that these side effects could be related to unknown functions of HDACs. The goal of this project is to identify novel, unsuspected functions of HDACs that will help developing more efficient and specific HDAC-based antitumoral therapies. To identify novel functions of HDACs, we used a high-throughput yeast two hybrid (Y2H) approach. This led to the first comprehensive interactomic map of class IIa HDACs that includes 84 protein partners. Among new HDACs partners, we identified several RNA-binding proteins (RBPs) involved in mRNA processing. In this work, we focused on one, the alternative splicing regulator RBFOX2, and investigated its regulation by class IIa HDACs. Through various approaches, we verified that HDAC7 interacts with RBFOX2. In addition, we found that silencing of HDAC7 correlates with a decrease in stability of RBFOX2. Because we identified a potential CMA-specific KFERQ motif in RBFOX2, we tested the possibility that RBFOX2 might be degraded through Chaperone-Mediated Autophagy (CMA). Supporting this hypothesis, we found that RBFOX2 interacts with the co-chaperone HSC70. RBFOX2 levels are sensitive to CMA inducers, including serum starvation and 6AN. Interestingly, we found that a lysine residue in the KFERQ motif of RBFOX2 is acetylated, suggesting that HDAC7 might control RBFOX2 degradation through reversible acetylation. Indeed, degradation of RBFOX2 following HDAC7 silencing was reverted with an inhibitor of autophagy, bafilomycin A1. Analysis of RNA splicing pattern in cells depleted for HDAC7 showed that absence of HDAC7 is associated with 159 alternative splicing events. These events mostly include exon skipping that is known to be the major splicing event in which RBFOX2 is involved. In addition, we observed a highly statistically overlap between splicing events associated with RBFOX2 and HDAC7 depletion. [less ▲]

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See detailClass IIa histone deacetylases: conducting development and differentiation.
Martin, Maud ULg; Kettmann, Richard ULg; Dequiedt, Franck ULg

in International Journal of Developmental Biology (2009), 53(2-3), 291-301

The emergence of specialized cell types and their organisation into organs and tissues involve the temporal modulation of many genes that are essential for coordinating the correct timing of instructive ... [more ▼]

The emergence of specialized cell types and their organisation into organs and tissues involve the temporal modulation of many genes that are essential for coordinating the correct timing of instructive signals. These transcriptional changes are orchestrated with a precision that reminds that of a classical symphony. Extracellular signals are transmitted to key integrators, which then orchestrate activation or repression of specific genes. In the last decade, class IIa HDACs have emerged as crucial regulators in various developmental and differentiation processes. This review focuses on the latest studies that have provided new insights into the biological functions of class IIa HDACs and discusses important aspects of their regulation. Elucidating cellular and molecular mechanisms by which functions of class IIa HDACs are modulated could potentially lead to new therapeutic opportunities for various diseases. [less ▲]

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See detailClass IIa histone deacetylases: regulating the regulators.
Martin, Maud ULg; Kettmann, Richard ULg; Dequiedt, Franck ULg

in Oncogene (2007), 26(37),

n the last decade, the identification of enzymes that regulate acetylation of histones and nonhistone proteins has revealed the key role of dynamic acetylation and deacetylation in various cellular ... [more ▼]

n the last decade, the identification of enzymes that regulate acetylation of histones and nonhistone proteins has revealed the key role of dynamic acetylation and deacetylation in various cellular processes. Mammalian histone deacetylases (HDACs), which catalyse the removal of acetyl groups from lysine residues, are grouped into three classes, on the basis of similarity to yeast counterparts. An abundance of experimental evidence has established class IIa HDACs as crucial transcriptional regulators of various developmental and differentiation processes. In the past 5 years, a tremendous effort has been dedicated to characterizing the regulation of these enzymes. In this review, we summarize the latest discoveries in the field and discuss the molecular and structural determinants of class IIa HDACs regulation. Finally, we emphasize that comprehension of the mechanisms underlying class IIa HDAC functions is essential for potential therapeutic applications. [less ▲]

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See detailA Class of Methods for the Analysis of Blade Tip Timing Data from Bladed Assemblies Undergoing Simultaneous Resonances—Part I: Theoretical Development
Gallego-Garrido, Jon; Dimitriadis, Grigorios ULg; Wright, Jan Robert

in International Journal of Rotating Machinery (2007), 2007

Blade tip timing is a technique for the measurement of vibrations in rotating bladed assemblies. Although the fundamentals of the technique are simple, the analysis of data obtained in the presence of ... [more ▼]

Blade tip timing is a technique for the measurement of vibrations in rotating bladed assemblies. Although the fundamentals of the technique are simple, the analysis of data obtained in the presence of simultaneously occurring synchronous resonances is problematic. A class of autoregressive-based methods for the analysis of blade tip timing data from assemblies undergoing two simultaneous resonances has been developed. It includes approaches that assume both sinusoidal and general blade tip responses. The methods can handle both synchronous and asynchronous resonances. An exhaustive evaluation of the approaches was performed on simulated data in order to determine their accuracy and sensitivity. One of the techniques was found to perform best on asynchronous resonances and one on synchronous resonances. Both methods yielded very accurate vibration frequency estimates under all conditions of interest. [less ▲]

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See detailA Class of Methods for the Analysis of Blade Tip Timing Data from Bladed Assemblies Undergoing Simultaneous Resonances—Part II: Experimental Validation
Gallego-Garrido, Jon; Dimitriadis, Grigorios ULg; Carrington, Ian B. et al

in International Journal of Rotating Machinery (2007), 2007

Blade tip timing is a technique for the measurement of vibrations in rotating bladed assemblies. In Part I of this work a class of methods for the analysis of blade tip timing data from bladed assemblies ... [more ▼]

Blade tip timing is a technique for the measurement of vibrations in rotating bladed assemblies. In Part I of this work a class of methods for the analysis of blade tip timing data from bladed assemblies undergoing two simultaneous synchronous resonances was developed. The approaches were demonstrated using data from a mathematical simulation of tip timing data. In Part II the methods are validated on an experimental test rig. First, the construction and characteristics of the rig will be discussed. Then, the performance of the analysis techniques when applied to data from the rig will be compared and analysed. It is shown that accurate frequency estimates are obtained by all the methods for both single and double resonances. Furthermore, the recovered frequencies are used to calculate the amplitudes of the blade tip responses. The presence of mistuning in the bladed assembly does not affect the performance of the new techniques. [less ▲]

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See detailClass V β Tubulin during the development of the organ of Corti in rat
Renauld, Justine ULg; Thelen, Nicolas ULg; Johnen, Nicolas ULg et al

Poster (2013, September 13)

In eutherian mammals, the organ responsible for the transduction of sound waves into nerve impulses is called the organ of Corti. This structure located within the cochlea, a portion of the inner ear, is ... [more ▼]

In eutherian mammals, the organ responsible for the transduction of sound waves into nerve impulses is called the organ of Corti. This structure located within the cochlea, a portion of the inner ear, is composed by two types of cells: sensory hair cells and non-sensory supporting cells. All these cells are distributed according to a specific arrangement along the whole length of the cochlea. A feature of the organ of Corti’s supporting cell is the presence of an abundant cytoskeleton. This one is mainly composed of microtubules, structures make up by tubulin heterodimers. The heterodimers consist of one molecule of α tubulin and one molecule of β tubulin. β tubulin isotypes are highly conserved in evolution and differ by only a few amino acid residues, implying that the isotypes may have functional significance. Organ of Corti’s supporting cells are constituted by class V β-tubulin, a minor mammalian tubulin (Bhattacharya et al., 2008). Moreover, their microtubules are formed by 15 protofilaments instead of the canonical 13, a unique fact among vertebrates (Banerjee et al., 2008). Such a configuration of protofilaments has been observed in C. elegans’ neurons which are responsible for the mechanosensory sense of touch (Bounoutas et al., 2009). It was also shown that these 15 protofilaments microtubules were essential to the proper functioning of these mechanosensory neurons (Bounoutas et al., 2009). Here we present the spatiotemporal localization of class V β-tubulin during the development of the organ of Corti in rats from embryonic day 18 (E18) until P25 (25th postnatal day). For this purpose, we have used immunolabelings on cryosections of whole cochlea. Our preliminary results demonstrate that class V β-tubulin has a unique distribution in the cochlea, being restricted to supporting cells, especially in pillar cells. [less ▲]

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See detailA class-A beta-lactamase from Pseudomonas stutzeri that is highly active against monobactams and cefotaxime.
Franceschini, N.; Galleni, Moreno ULg; Frère, Jean-Marie ULg et al

in The Biochemical journal (1993), 292 ( Pt 3)

A beta-lactamase produced by Pseudomonas stutzeri was purified to protein homogeneity, and its physicochemical and catalytic properties were determined. Its profile was unusual since, in addition to ... [more ▼]

A beta-lactamase produced by Pseudomonas stutzeri was purified to protein homogeneity, and its physicochemical and catalytic properties were determined. Its profile was unusual since, in addition to penicillins, the enzyme hydrolysed second- and third-generation 'beta-lactamase-stable' cephalosporins and monobactams with similar efficiencies. On the basis of the characteristics of the interaction with beta-iodopenicillanic acid, the enzyme could be classified as a class-A beta-lactamase. However, when compared with most class-A beta-lactamases, it exhibited significantly lower kcat./Km values for the compounds usually considered to be the best substrates of these enzymes. [less ▲]

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See detailLa classe de langue comme observatoire et laboratoire d'un apprentissage expérientiel des langues étrangères à travers la pédagogie par projet
Simons, Germain ULg

in Etudes & Travaux (1999), (3), 67-84

G. Simons begins by pointing out the difficulties encountered by many language teachers in trying to provide students with real communication situations. According to the author, the methodological ... [more ▼]

G. Simons begins by pointing out the difficulties encountered by many language teachers in trying to provide students with real communication situations. According to the author, the methodological approach which consists in asking students to "imagine they are Mr Smith" hardly conceals its formal interest. Furthemore, it should be completed with an experiential approach aiming at an articulation of the active experimentation of the foreign language in the here and now as well as the analysis of the functioning of the language as a system. The preparation and exploitation of a pedagogical project for a linguistic stay provides the foreign language course with a concrete aim and a real linguistic material, which it often lacks. In analysing and comparing the linguistic data from students and native speakers in real and identical communication situations, the language teacher can test the interlanguage of his students. Moreover, this process of comparison enables the language teacher to make students "notice the gap" between their language production and that of native speakers. This "notice the gap" technique transforms the traditional language class into an observatory and laboratory of the foreign language and of the interlanguage. [less ▲]

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See detailLe classement des bois feuillus sur pied
Jourez, Benoît ULg; de Wauters, Philippe; Bienfait, Orane

in Silva Belgica (2010), 117

Cet article a pour objectif de se familiariser avec les critères d’estimation de la qualité et du classement des bois feuillus. Cette technique relativement subjective répartit la ressource en différentes ... [more ▼]

Cet article a pour objectif de se familiariser avec les critères d’estimation de la qualité et du classement des bois feuillus. Cette technique relativement subjective répartit la ressource en différentes catégories correspondant à des qualités particulières. Avec l’expérience, il est possible d’évaluer la valeur d’un arbre assez rapidement sur base de critères simples. Néanmoins, cette valeur globale dépend du prix attribué à chaque qualité. Le prix est en effet lié à de nombreux paramètres tels que l’offre et la demande, les quantités proposées, les conditions d’exploitation, la confiance de l’acheteur, la connaissance des marchés potentiels, … [less ▲]

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See detailClassement par ordre d'importance des zoonoses alimentaires : méthodes et application à la situation belge
Cardoen, S.; Van Huffel, X.; Berkvens, D. et al

in Epidémiologie et Santé Animale (2009), 55

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See detailUn classement supervisé de l’utilisation du sol et son exploitation dans l’agglomération liégeoise à partir d’une scène SPOT
Nadasdi, Istvan; Baudot, Yves; Donnay, Jean-Paul ULg et al

in Télédétection satellitaire et espaces urbains (1987)

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See detailClasses (effets, composition, fonctionnement)
Lafontaine, Dominique ULg

in Van Zantem (Ed.) Dictionnaire de l'éducation (2008)

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See detailClasses, conscience de classe et "classe politique"
Counet, Maxime ULg

Master's dissertation (2014)

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See detailClassical analogy for the deflection of flux avalanches by a metallic layer
Silhanek, Alejandro ULg

Conference (2015, May 17)

Motivated by the experimental observation of the exclusion of magnetic flux avalanches in a superconducting sample partially covered by a conducting capping layer, we have investigated the simpli fied ... [more ▼]

Motivated by the experimental observation of the exclusion of magnetic flux avalanches in a superconducting sample partially covered by a conducting capping layer, we have investigated the simpli fied case of the interaction of a magnetic charge (monopole and dipole) with a semi-in finite conducting plane. We have found that early theoretical descriptions for the damping enhancement due to the metallic sheet needed a correction at large vortex velocities where a decrease of the damping coe fficient is expected. We also demonstrate that vortex trajectories are strongly modi fied when penetrating into the area covered by the metallic sheet and may even be fully diverted from that area thus providing a qualitative explanation for the bending of the trajectories of flux avalanches. Our fi ndings may be extended to study the damping of Larkin-Ovchinnikov vortex instabilities and phase-slip lines in current driven systems. [less ▲]

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See detailClassical analogy for the deflection of flux avalanches by a metallic layer
Silhanek, Alejandro ULg

Conference (2014, August 31)

Sudden avalanches of magnetic flux bursting into a superconducting sample undergo deflections of their trajectories when encountering a conductive layer deposited on top of the superconductor. Remarkably ... [more ▼]

Sudden avalanches of magnetic flux bursting into a superconducting sample undergo deflections of their trajectories when encountering a conductive layer deposited on top of the superconductor. Remarkably, in some cases the flux is totally excluded from the area covered by the conductive layer. We present a simple classical model that accounts for this behaviour and considers a magnetic monopole approaching a semi-infinite conductive plane. This model suggests that magnetic braking is an important mechanism responsible for avalanche deflection. [less ▲]

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See detailClassical analogy for the deflection of flux avalanches by a metallic layer
Brisbois, Jérémy ULg; Vanderheyden, Benoît ULg; Colauto, Fabiano et al

in New Journal of Physics (2014), 16(10), 103003

Sudden avalanches of magnetic flux bursting into a superconducting sample undergo deflections of their trajectories when encountering a conductive layer deposited on top of the superconductor. Remarkably ... [more ▼]

Sudden avalanches of magnetic flux bursting into a superconducting sample undergo deflections of their trajectories when encountering a conductive layer deposited on top of the superconductor. Remarkably, in some cases the flux is totally excluded from the area covered by the conductive layer. We present a simple classical model that accounts for this behaviour and considers a magnetic monopole approaching a semi-infinite conductive plane. This model suggests that magnetic braking is an important mechanism responsible for avalanche deflection. [less ▲]

Detailed reference viewed: 113 (47 ULg)