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See detailIdentification of Bayesian posteriors for coefficients of chaos expansions
Arnst, Maarten ULg; Ghanem, Roger; Soize, Christian

in Journal of Computational Physics (2010), 229(9), 3134-3154

This article is concerned with the identification of probabilistic characterizations of random variables and fields from experimental data. The data used for the identification consist of measurements of ... [more ▼]

This article is concerned with the identification of probabilistic characterizations of random variables and fields from experimental data. The data used for the identification consist of measurements of several realizations of the uncertain quantities that must be characterized. The random variables and fields are approximated by a polynomial chaos expansion, and the coefficients of this expansion are viewed as unknown parameters to be identified. It is shown how the Bayesian paradigm can be applied to formulate and solve the inverse problem. The estimated polynomial chaos coefficients are hereby themselves characterized as random variables whose probability density function is the Bayesian posterior. This allows to quantify the impact of missing experimental information on the accuracy of the identified coefficients, as well as on subsequent predictions. An illustration in stochastic aeroelastic stability analysis is provided to demonstrate the proposed methodology. [less ▲]

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See detailIdentification of biochemical reaction networks using a parameter-free coordinate system
Fey, Dirk ULg; Findeisen, Rolf; Bullinger, Eric ULg

in Iglesias, P. A.; Ingalls, B. (Eds.) Control-Theoretic Approaches in Systems Biology (2009)

A fundamental step in systems biology is the estimation of kinetic parameters, such as association and dissociation constants. Often, their direct estimation from in-vivo studies on isolated reactions is ... [more ▼]

A fundamental step in systems biology is the estimation of kinetic parameters, such as association and dissociation constants. Often, their direct estimation from in-vivo studies on isolated reactions is expensive, time-consuming or even infeasible. Therefore, it is necessary to estimate them from indirect measurements, such as time-series data. This chapter proposes an observer-based parameter estimation methodology particularly suited for biochemical reaction networks in which the reaction kinetics are described by polynomial or rational functions. The parameter estimation is performed in three steps. First, the system is transformed into a new set of coordinates in which the system is parameter-free. This facilitates the design of a standard observer in the second step. Finally, the parameter estimates are obtained in a straight-forward way from the observer states, transforming them back to the original coordinates. The approach is illustrated by an example of a MAP kinase signaling pathway. [less ▲]

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See detailIdentification of Biochemical reaction networks: challenges and possible solutions
Bullinger, Eric ULg

Scientific conference (2008, April 25)

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See detailIdentification of biomarkers to estrogen exposure using MCF-7/BOS cell line exposed to 17β-estradiol and phytoestrogens
Collodoro, Mike ULg; Bertrand, Virginie ULg; Lemaire, Pascale ULg et al

Poster (2009, June)

Use of an estrogen responsive cell line and proteomic for biomarker discovery and the screening of xenoestrogen

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See detailIdentification of BlaR, the signal transducer for β-lactamase production in Bacillus licheniformis, as a penicillin-binding protein with strong homology to the OXA-2 β-lactamase (class D) of Salmonella typhimurium
Zhu, Ying-Fang; Curran, Ivan H. A.; Joris, Bernard ULg et al

in Journal of Bacteriology (1990), 172(2), 1137-1141

The blaR gene of Bacillus licheniformis encodes the signal transducer for induction of the class A beta-lactamase. The protein product, BlaR, has a hydrophilic carboxy region that binds beta-lactams and ... [more ▼]

The blaR gene of Bacillus licheniformis encodes the signal transducer for induction of the class A beta-lactamase. The protein product, BlaR, has a hydrophilic carboxy region that binds beta-lactams and shows high sequence homology to the class D beta-lactamases, particularly the OXA-2 beta-lactamase of Salmonella typhimurium. The BlaR-beta-lactam complex is stable and may provide the continuing stimulus needed for the prolonged production of the enzyme. [less ▲]

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See detailIdentification of Brucella spp. genes involved in intracellular trafficking.
Delrue, R. M.; Martinez-Lorenzo, M.; Lestrate, P. et al

in Cellular Microbiology (2001), 3(7), 487-97

After uptake by host cells, the pathogen Brucella transits through early endosomes, evades phago-lysosome fusion and replicates in a compartment associated with the endoplasmic reticulum (ER). The ... [more ▼]

After uptake by host cells, the pathogen Brucella transits through early endosomes, evades phago-lysosome fusion and replicates in a compartment associated with the endoplasmic reticulum (ER). The molecular mechanisms underlying these processes are still poorly understood. To identify new bacterial factors involved in these processes, a library of 1800 Brucella melitensis 16M mini-Tn5catkm mutants was screened for intracellular survival and multiplication in HeLa cells and J774A.1 macrophages. Thirteen mutants were identified as defective for their intracellular survival in both cell types. In 12 of them, the transposon had inserted in the virB operon, which encodes a type IV-related secretion system. The preponderance of virB mutants demonstrates the importance of this secretion apparatus in the intracellular multiplication of B. melitensis. We also examined the intracellular fate of three virB mutants (virB2, virB4 and virB9) in HeLa cells by immunofluorescence. The three VirB proteins are not necessary for penetration and the inhibition of phago-lysosomal fusion within non-professional phagocytes. Rather, the virB mutants are unable to reach the replicative niche and reside in a membrane-bound vacuole expressing the late endosomal marker, LAMP1, and the sec61beta protein from the ER membrane, proteins that are present in autophagic vesicles originating from the ER. [less ▲]

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See detailIdentification of cardiac repercussions after intense and prolonged concentric isokinetic exercise in young sedentary people.
LE GOFF, Caroline ULg; Kaux, Jean-François ULg; Couffignal, Vincent et al

in Clinical physiology and functional imaging (in press)

INTRODUCTION: Cardiopathies are the world's leading cause of mortality and morbidity. Although rare, cardiovascular accidents can occur during intense and infrequent sporting activity, particularly among ... [more ▼]

INTRODUCTION: Cardiopathies are the world's leading cause of mortality and morbidity. Although rare, cardiovascular accidents can occur during intense and infrequent sporting activity, particularly among those who are unaware of their heart condition. The development of cardiospecific biochemical markers has led to a reconsideration of the role of biology in the diagnosis of cardiovascular illnesses. The aim of this study therefore was, through the use of cardiac biomarker assays, to highlight the impact of sustained physical effort in the form of intense and prolonged concentric isokinetic exercise and to research potential cardiovascular risks. MATERIALS AND METHODS: Eighteen subjects participated in a maximal concentric isokinetic exercise involving 30 knee flexion-extensions for each leg. Five blood tests were taken to study the kinetics of the cardiac biomarkers. Haemodynamic parameters were measured continuously using a Portapres, and respiratory parameters were measured using a Sensormedics Vmax 29C. RESULTS: The results showed significant increases in the creatine kinase, myoglobin, homocysteine and haemoglobin cardiac markers. Evolutionary trends were also observed for the following biomarkers: NT-proBNP, myeloperoxydase and C-reactive protein. All the physiological parameters measured presented statistically significant changes. CONCLUSION: Isokinetic effort leads to the release of cardiac markers in the blood, but these do not exceed the reference values in healthy subjects. Maximal concentric isokinetic exercise does not, therefore, lead to an increased risk of cardiovascular pathologies. [less ▲]

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See detailIdentification of Catecholaminergic Inputs to and Outputs from Aromatase-Containing Brain Areas of the Japanese Quail by Tract Tracing Combined with Tyrosine Hydroxylase Immunocytochemistry
Balthazart, Jacques ULg; Absil, Philippe ULg

in Journal of Comparative Neurology (The) (1997), 382(3), 401-28

In the quail brain, aromatase-immunoreactive (ARO-ir) neurons located in the medial preoptic nucleus (POM) and caudal paleostriatum ventrale/nucleus accumbens/nucleus striae terminalis complex (PVT/nAc ... [more ▼]

In the quail brain, aromatase-immunoreactive (ARO-ir) neurons located in the medial preoptic nucleus (POM) and caudal paleostriatum ventrale/nucleus accumbens/nucleus striae terminalis complex (PVT/nAc/nST) receive catecholaminergic inputs identified by the presence of tyrosine hydroxylase-immunoreactive (TH-ir) fibers and punctate structures. The origin of these inputs was analyzed by retrograde tracing with cholera toxin B subunit (CTB) or red latex fluospheres (RLF) combined with TH immunocytochemistry. CTB and RLF injected in the POM or PVT/nAc/nST were found in cells located in anatomically discrete areas in the telencephalon (hippocampus, septum, archistriatum), hypothalamus (many areas in periventricular position), thalamus, mesencephalon, and pons. In these last two regions, many retrogradely labeled cells were located in dopaminergic areas such as the retroruberal field (RRF), substantia nigra (SN), and area ventralis of Tsai (AVT) but also in noradrenergic cell groups such as the locus ceruleus and subceruleus. CTB tracing showed that most of these connections are bidirectional. Many retrogradely labeled cells contained TH-ir material. As a mean, 10-20% and 40-60% of the RLF-containing cells in the dopaminergic areas were TH-ir when RLF had been injected in the POM or PVT/nAc/nST, respectively. TH-ir cells projecting to the POM appeared to be mostly located in the periventricular hypothalamus and in AVT, whereas projections to the PVT/nAc/nST originated mainly in the SN (with significant contributions from the RRF and AVT). These data support the existence of functional relationships between aromatase and catecholamines. [less ▲]

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See detailIdentification of chemical probes and signaling pathways for the orphan GPCR GPR27
Dupuis, Nadine ULg; Gilissen, Julie ULg; Pirotte, Bernard ULg et al

Poster (2013, June 06)

The largest family of membrane receptors is represented by G protein-coupled receptors (GPCRs), which are characterized by 7 transmembrane domains. Even if marketed drugs currently target only 10% of all ... [more ▼]

The largest family of membrane receptors is represented by G protein-coupled receptors (GPCRs), which are characterized by 7 transmembrane domains. Even if marketed drugs currently target only 10% of all GPCRs, they represent more than 30% of all small molecules based therapies. The physiological and pathophysiological role of a GPCR is defined by its expression pattern, signaling pathway and specific ligand[1]. GPCRs which have not yet been associated to a physiological ligand are called orphan GPCRs and represent ~100 of the ~370 human non-odorant GPCRs[2]. This project aims at identifying and developing pharmacological tools for GPR27 (SREB1), one of these orphan receptors. GPR27 has recently been shown to have a role in the regulation of insulin promoter activity and insulin secretion[3]. Nevertheless, the pharmacology of GPR27 remains elusive and the lack of appropriate pharmacological tools dramatically restricts the understanding of its function and its validation as a drug target. Thus, we plan to study its signaling pathway and to develop screening methods that will allow us to identify small molecules able to interact with GPR27. These are important steps toward understanding its function and evaluating GPR27 as a potential drug target, for instance in insulin-related metabolic disorders such as type II diabetes or in other pathologies where it might be involved. References 1) Wise, A., et al. (2002). Drug discovery today, 7, 235 2) Fredriksson, R., et al. (2003). Molecular pharmacology, 63, 1256 3) Ku, G. M., et al. (2012). PLoS genetics, 8, e1002449 [less ▲]

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See detailIdentification of cis-regulatory elements controlling two differentially expressed Pit-1 genes in the duplicated genome of Cyprinus carpio
Kausel, G. M.; Castro, L. A.; Vera, T. S. et al

in FEBS Journal (2005, July), 272(Suppl. 1), 469-470

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See detailIdentification of Clostridium tyrobutyricum and related species using sugar fermentation, organic acid formation and DNA probes based on 16S rRNA sequences
Klijn, N.; Bovie, C.; Dommes, Jacques ULg et al

in Systematic and Applied Microbiology (1994), 17(2), 249-256

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See detailIdentification of coiled body-like structures in meristematic cells of Pisum sativum cotyledonary buds.
Jennane, A.; Thiry, Marc ULg; Goessens, Guy ULg

in Chromosoma (1999), 108(2), 132-42

This study focused on two types of nuclear bodies visible in plant cells that were previously thought to be similar to the coiled bodies (CBs) of animal cells: the nucleolus-associated body (NAB) and ... [more ▼]

This study focused on two types of nuclear bodies visible in plant cells that were previously thought to be similar to the coiled bodies (CBs) of animal cells: the nucleolus-associated body (NAB) and dense body (DB). We show that both NABs and DBs share common features with animal CBs: they consist of ribonucleoproteins, are silver-stainable, and lack DNA. Immunoelectron microscopy shows that only the NABs are rich in snRNAs and fibrillarin, two markers characteristic of animal CBs. This suggests that NABs rather than DBs are the plant counterparts of the CBs of animal cells. These structures appear most frequently in cells blocked in G0-1, their frequency gradually declining with resumption of the cell cycle and nucleolar activity. During this reactivation period, NABs are released from the nucleolus to the nucleoplasm, suggesting that they may act as nuclear transport or sorting structures. [less ▲]

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See detailIdentification of COX-2 selective inhibitor
Michaux, C.; Julémont, F.; de Leval, X. et al

in Fundamental & Clinical Pharmacology (2004)

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See detailIdentification of cyclooxygenase-2 as a major actor of the transcriptomic adaptation of endothelial and tumor cells to cyclic hypoxia: effect on angiogenesis and metastases.
Daneau; Boidot; MARTINIVE, Philippe ULg et al

in Clinical Cancer Research : An Official Journal of the American Association for Cancer Research (2010), 16(2), 410-419

Purpose: Cyclic hypoxia in tumors originates from heterogeneities in RBC flux and influences not only tumor cells but also endothelial cells lining tumor blood vessels. Whether pO2 fluctuations ... [more ▼]

Purpose: Cyclic hypoxia in tumors originates from heterogeneities in RBC flux and influences not only tumor cells but also endothelial cells lining tumor blood vessels. Whether pO2 fluctuations, particularly transient reoxygenation periods, alter the well-known hypoxia-inducible factor (HIF)–dependent gene program is largely unknown. Experimental Design: We compared the transcriptomic profiles of endothelial and tumor cells exposed to cyclic hypoxia versus continuous hypoxia to uncover a possible differential effect on angiogenesis and metastases. Results: Microarray analyses identified early genes that were selectively induced by cyclic hypoxia in endothelial cells. Among them, we focused on PTGS2 because the observed increase in mRNA expression led to a significant increase in the expression and activity of cyclooxygenase-2 (COX-2; the protein product of PTGS2). HIF-1α was shown to be stabilized by cyclic hypoxia (despite reoxygenation periods) and to favor COX-2 induction as validated by the use of echinomycin and HIF-1α targeting small interfering RNA. Using a specific COX-2 inhibitor and a dedicated COX-2 targeting small interfering RNA, we documented that COX-2 accounted for the higher endothelial cell survival and angiogenic potential conferred by cyclic hypoxia. Cyclic hypoxia also led to a preferential COX-2 induction in tumor cells and, contrary to continuous hypoxia, fostered a higher metastatic take of prechallenged tumor cells. Conclusions: Our study documents that PTGS2/COX-2 is part of a cyclic hypoxia gene signature and largely accounts for the unique phenotype of endothelial and tumor cells exposed to fluctuations in pO2, thereby offering new perspectives for the clustering of tumors expressing COX-2 together with other cyclic hypoxia-responsive genes. Clin Cancer Res; 16(2); 410–9 [less ▲]

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See detailIdentification Of Cystosolic Mg2+-Dependent Soluble Inorganic Pyrophosphatases In Potato And Phylogenetic Analysis
Rojas-Beltran, Ja.; Dubois, Françoise ULg; Mortiaux, F. et al

in Plant Molecular Biology (1999), 39(3),

Detailed reference viewed: 25 (5 ULg)