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See detailCharacterization of synovial angiogenesis in osteoarthritis patients and its modulation by chondroitin sulfate
Lambert, Cécile ULg; Mathy-Hartert, Marianne; Dubuc, JE et al

in Arthritis Research & Therapy (2012), 14(2), 58

INTRODUCTION: This work aimed at comparing the production of inflammatory and pro- and anti-angiogenic factors by normal/reactive (N/R) or inflammatory (I) areas of the osteoarthritic synovial membrane ... [more ▼]

INTRODUCTION: This work aimed at comparing the production of inflammatory and pro- and anti-angiogenic factors by normal/reactive (N/R) or inflammatory (I) areas of the osteoarthritic synovial membrane. The effects of interleukin (IL)-1β and chondroitin sulfate (CS) on the expression of pro- and anti-angiogenic factors by synovial fibroblasts cells (SFC) were also studied. METHODS: Biopsies from N/R or from I areas of osteoarthritic synovial membrane were collected at the time of surgery. The inflammatory status of the synovial membrane was characterized by the surgeon according to macroscopic criteria, including the synovial vascularization, the villi formation and the hypertrophic aspect of the tissue. We assessed the expression of CD45, von Willebrand factor and vascular endothelial growth factor (VEGF) antigen by immunohistochemistry in both N/R and I biopsies. The production of IL-6, -8, VEGF and thrombospondin (TSP)-1 by N/R or I synovial cells was quantified by ELISA. SFC were cultured in the absence or in the presence of IL-1β (1 ng/ml) and with or without CS (10, 50, 200 μg/ml). Gene expression of pro-angiogenic factors (VEGF, basic fibroblast growth factor (bFGF), nerve growth factor (NGF), matrix metalloproteinase (MMP)-2 and angiopoietin (ang)-1) and anti-angiogenic factors (vascular endothelial growth inhibitor (VEGI), TSP-1 and -2) were determined by real time RT-PCR. Production of VEGI and TSP-1 was also estimated by ELISA. RESULTS: Immunohistochemistry showed the increase of lymphocyte infiltration, vascular density and VEGF expression in I compared to N/R synovial biopsies. Synovial cells from I areas produced more IL-6, IL-8 and VEGF but less TSP-1 than cells isolated from N/R synovial biopsies. The expression of pro-angiogenic factors by SFC was stimulated by IL-1β. A time dependent regulation of the expression of anti-angiogenic factor genes was observed. IL-1β stimulated the expression of anti-angiogenic factor genes but inhibited it after 24 h. CS reversed the inhibitory effect of IL-1β on anti-angiogenic factors, VEGI and TSP-1. CONCLUSIONS: We demonstrated that synovial biopsies from I areas expressed a pro-angiogenic phenotype. IL-1β induced an imbalance between pro- and anti-angiogenic factors in SFC and CS tended to normalize this IL-1β-induced imbalance, providing a new possible mechanism of action of this drug. [less ▲]

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See detailCharacterization of talcschist's weathering Materials in Henguegue (Cameroon)
Woguia, Damaris Laure ULg; Ngo Bidjeck, Louise Marie

Poster (2015, August 25)

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See detailCharacterization of tap intensity for granular compaction
Ludewig, François ULg; Dorbolo, Stéphane ULg; Vandewalle, Nicolas ULg

in Powders and Grains 2009 (2009)

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See detailCHARACTERIZATION OF TEN STRAINS OF FILAMENTOUS CYANOBACTERIA FROM THE SOUTH SHETLAND ISLANDS, MARITIME ANTARCTICA
Kovacik, Lubomir; Pereira, Antonio; Dusinsky, Roman et al

Poster (2015, September 07)

The evolutionary relationships of ten Antarctic cyanobacterial strains of the order Oscillatoriales isolated from King George Island and Deception Island, South Shetland Islands were studied by a ... [more ▼]

The evolutionary relationships of ten Antarctic cyanobacterial strains of the order Oscillatoriales isolated from King George Island and Deception Island, South Shetland Islands were studied by a polyphasic approach. Phenotypic observations of the morphological features and genotypic analyses (16S rRNA and ITS sequences) were performed. Based on major phenotypic features, the strains were divided into four distinct morphotypes: Leptolyngbya borchgrevinkii (A), Leptolyngbya frigida (B), Phormidium autumnale (C) and Wilmottia murrayi (D). This morphological identification was in global agreement with the evolutionary relationships. According to the phylogenetic analysis, the ten strains were divided into two major clades, containing related strain sequences with Leptolyngbya morphotypes in one clade and with morphotypes corresponding to Phormidium, Wilmottia and Microcoleus spp. in the other clade. Each major clade was divided into two sub-clades. For the first time, the 16S rRNA gene sequence of a strain corresponding to the Leptolyngbya borchgrevinkii morphotype (A) was determined, on the basis of strain KOVACIK-ANT 1990/4. The closest sequence to our morphotype A is the clone Fr252 isolated from microbial mat of Antarctic Lake Fryxell. Morphotype B is closest to sequences assigned to Leptolyngbya frigida isolated from microbial mats of lakes in continental East Antarctica. Morphotype C belongs to a cluster including strains with morphotypes corresponding to Phormidium autumnale from Antarctica, but also from Europe. Morphotype D is grouped with sequences of the morphotype assigned to Wilmottia murrayi isolated from Antarctica. [less ▲]

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See detailCharacterization of the antimicrobial activity of mycosubtilin on the plasma membranes. A biomimetic approach
Nasir, Mehmet Nail ULg; Besson, Françoise

Poster (2010)

Mycosubtilin, an antimicrobial lipopeptide, is produced by Bacillus subtilis strains. It belongs to the iturin family, which is characterized by the presence of a peptide part, constituted of a constant ... [more ▼]

Mycosubtilin, an antimicrobial lipopeptide, is produced by Bacillus subtilis strains. It belongs to the iturin family, which is characterized by the presence of a peptide part, constituted of a constant chiral amino acid sequence cycled by a β-amino fatty acid (Fig. 1). As all the iturinic lipopeptides, mycosubtilin exhibits its biocide activities on cytoplasmic membrane of target cells [1]. Recently, the activity of mycosubtilin on pathogenic strains resistant to classical agents was shown [2]. However, despite many works focused on its structure and the optimization of its production, only a few studies are conducted to analyze mycosubtilin-membrane interactions. The purpose of our work was to better understand, at the molecular level, the mechanisms of the mycosubtilin activity on cytoplasmic membranes. Firstly, we modelled the mycosubtilin-membrane interactions by using biomimetic monolayers and their associated techniques (tensiometry and PM-IRRAS). After characterizing the interfacial properties of pure mycosubtilin [3], we used Langmuir films to investigate the mycosubtilin behavior when the lipopeptide reaches the external leaflet of the membrane. We found that the mycosubtilin adsorption to lipid monolayers depended on their lipid composition and the lipopeptide interaction with the membrane was facilitated by the presence of sterols. Then, we mimicked the insertion of the lipopeptide in the whole membrane by using multilamellar vesicles. FT-IR spectroscopy analysis showed that the interaction of mycosubtilin with the artificial membranes induced conformational changes of the lipopeptide only in the presence of sterol. 1. Maget-Dana R, Peypoux F. (1994) Toxicology 87:151-74. 2. Fickers P, Guez JS, Damblon C, Leclère V, Béchet M, Jacques P, Joris B. (2009) Appl. Environ. Microbiol. 75:4636-40. 3. Nasir MN, Thawani A, Kouzayha A, Besson F. (2010) Colloids Surf. B Biointerfaces 78 :17-23. [less ▲]

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See detailCharacterization of the Behaviour of a Simple Aeroservoelastic System with Control Nonlinearities
Dimitriadis, Grigorios ULg; Cooper, Jonathan E

in Journal of Fluids & Structures (2000), 14(8), 1173-1193

The characterization of the behaviour of nonlinear aeroelastic systems has become a very important research topic in the Aerospace Industry. However, most work carried to-date has concentrated upon ... [more ▼]

The characterization of the behaviour of nonlinear aeroelastic systems has become a very important research topic in the Aerospace Industry. However, most work carried to-date has concentrated upon systems containing structural or aerodynamic nonlinearities. The purpose of this paper is to study the stability of a simple aeroservoelastic system with nonlinearities in the control system and power control unit. The work considers both structural and control law nonlinearities and assesses the stability of the system response using bifurcation diagrams. It is shown that simple feedback systems designed to increase the stability of the linearized system also stabilize the nonlinear system, although their effects can be less pronounced. Additionally, a nonlinear control law designed to limit the control surface pitch response was found to increase the flutter speed considerably by forcing the system to undergo limit cycle oscillations instead of fluttering. Finally, friction was found to affect the damping of the system but not its stability, as long as the amplitude of the frictional force is low enough not to cause stoppages in the motion. [less ▲]

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See detailCharacterization of the Benchmark Binary NLTT 33370
Schlieder, Joshua E.; Bonnefoy, Mickaël; Herbst, T. M. et al

in Astrophysical Journal (2014), 783

We confirm the binary nature of the nearby, very low mass (VLM) system NLTT 33370 with adaptive optics imaging and present resolved near-infrared photometry and integrated light optical and near-infrared ... [more ▼]

We confirm the binary nature of the nearby, very low mass (VLM) system NLTT 33370 with adaptive optics imaging and present resolved near-infrared photometry and integrated light optical and near-infrared spectroscopy to characterize the system. VLT-NaCo and LBTI-LMIRCam images show significant orbital motion between 2013 February and 2013 April. Optical spectra reveal weak, gravity-sensitive alkali lines and strong lithium 6708 Å absorption that indicate the system is younger than field age. VLT-SINFONI near-IR spectra also show weak, gravity-sensitive features and spectral morphology that is consistent with other young VLM dwarfs. We combine the constraints from all age diagnostics to estimate a system age of ~30-200 Myr. The 1.2-4.7 μm spectral energy distribution of the components point toward T [SUB]eff[/SUB] = 3200 ± 500 K and T [SUB]eff[/SUB] = 3100 ± 500 K for NLTT 33370 A and B, respectively. The observed spectra, derived temperatures, and estimated age combine to constrain the component spectral types to the range M6-M8. Evolutionary models predict masses of 97^{+41}_{-48}\,M_{Jup} and 91^{+41}_{-44}\,M_{Jup} from the estimated luminosities of the components. KPNO-Phoenix spectra allow us to estimate the systemic radial velocity of the binary. The Galactic kinematics of NLTT 33370AB are broadly consistent with other young stars in the solar neighborhood. However, definitive membership in a young, kinematic group cannot be assigned at this time and further follow-up observations are necessary to fully constrain the system's kinematics. The proximity, age, and late-spectral type of this binary make it very novel and an ideal target for rapid, complete orbit determination. The system is one of only a few model calibration benchmarks at young ages and VLMs. [less ▲]

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See detailCharacterization of the bifunctional glycosyltransferase/acyltransferase penicillin-binding protein 4 of Listeria monocytogenes
Zawadzka-Skomial, J.; Markiewicz, Z.; Nguyen-Disteche, M. et al

in Journal of Bacteriology (2006), 188(5), 1875-1881

Multimodular penicillin-binding proteins (PBPs) are essential enzymes responsible for bacterial cell wall peptidoglycan (PG) assembly. Their glycosyltransferase activity catalyzes glycan chain elongation ... [more ▼]

Multimodular penicillin-binding proteins (PBPs) are essential enzymes responsible for bacterial cell wall peptidoglycan (PG) assembly. Their glycosyltransferase activity catalyzes glycan chain elongation from lipid II substrate (undecaprenyl-pyrophosphoryi-N-acetylglucosamine-N-acetylmuramic acid-pentapeptide), and their transpeptidase activity catalyzes cross-linking between peptides carried by two adjacent glycan chains. Listeria monocytogenes is a food-borne pathogen which exerts its virulence through secreted and cell wall PG-associated virulence factors. This bacterium has five PBPs, including two bifunctional glycosyltransferase/transpeptidase class A PBPs, namely, PBP1 and PBP4. We have expressed and purified the latter and have shown that it binds penicillin and catalyzes in vitro glycan chain polymerization with an efficiency of 1,400 M-1 s(-1) from Escherichia coli lipid II substrate. PBP4 also catalyzes the aminolysis (D-Ala as acceptor) and hydrolysis of the thiolester donor substrate benzoyl-Gly-thioglycolate, indicating that PBP4 possesses both transpeptidase and carboxyeptidase activities. Disruption of the gene lmo2229 encoding PBP4 in L. monocytogenes EGD did not. p have any significant effect on growth rate, peptidoglycan composition, cell morphology, or sensitivity to beta-lactam antibiotics but did increase the resistance of the mutant to moenomycin. [less ▲]

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See detailCharacterization of the bovine pseudoautosomal boundary: Documenting the evolutionary history of mammalian sex chromosomes.
Van Laere, Anne-Sophie ULg; Coppieters, Wouter ULg; Georges, Michel ULg

in Genome Research (2008), 18(12), 1884-95

Here, we report the sequence characterization of the bovine pseudoautosomal boundary (PAB) and its neighborhood. We demonstrate that it maps to the 5' end of the GPR143 gene, which has concomitantly lost ... [more ▼]

Here, we report the sequence characterization of the bovine pseudoautosomal boundary (PAB) and its neighborhood. We demonstrate that it maps to the 5' end of the GPR143 gene, which has concomitantly lost upstream noncoding exons on the Y chromosome. We show that the bovine PAB was created approximately 20.7 million years ago by illegitimate intrachromatid recombination between inverted, ruminant-specific Bov-tA repeats. Accordingly, we demonstrate that cattle share their PAB with all other examined ruminants including sheep, but not with cetaceans or more distantly related mammals. We provide evidence that, since its creation, the ancestral ruminant PAB has been displaced by attrition, which occurs at variable rates in different species, and that it is capable of retreat by attrition erasure. We have estimated the ratio of male to female mutation rates in the Bovidae family as approximately 1.7, and we provide evidence that the mutation rate is higher in the recombining pseudoautosomal region than in the adjacent, nonrecombining gonosome-specific sequences. [less ▲]

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See detailCharacterization of the C-Terminal Propeptide Involved in Bacterial Wall Spanning of Alpha-Amylase from the Psychrophile Alteromonas Haloplanctis
Feller, Georges ULg; D'Amico, Salvino ULg; Benotmane, A. M. et al

in Journal of Biological Chemistry (1998), 273(20), 12109-15

The antarctic psychrophile Alteromonas haloplanctis secretes a Ca2+- and Cl--dependent alpha-amylase. The nucleotide sequence of the amy gene and the amino acid sequences of the gene products indicate ... [more ▼]

The antarctic psychrophile Alteromonas haloplanctis secretes a Ca2+- and Cl--dependent alpha-amylase. The nucleotide sequence of the amy gene and the amino acid sequences of the gene products indicate that the alpha-amylase precursor is a preproenzyme composed by the signal peptide (24 residues), the mature alpha-amylase (453 residues, 49 kDa), and a long C-terminal propeptide or secretion helper (192 residues, 21 kDa). In cultures of the wild-type strain, the 70-kDa precursor is secreted at the mid-exponential phase and is cleaved by a nonspecific protease into the mature enzyme and the propeptide. The purified C-terminal propeptide displays several features common to beta-pleated transmembrane proteins. It has no intramolecular chaperone function because active alpha-amylase is expressed by Escherichia coli in the absence of the propeptide coding region. In E. coli, the 70-kDa precursor is directed toward the supernatant. When the alpha-amylase coding region is excised from the gene, the secretion helper can still promote its own membrane spanning. It can also accept a foreign passenger, as shown by the extracellular routing of a beta-lactamase-propeptide fusion protein. [less ▲]

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See detailCharacterization of the caprine (Capra hircus) beta-2 integrin CD18-encoding cDNA and identification of mutations potentially responsible for the ruminant-specific virulence of Mannheimia haemolytica
Zecchinon, Laurent ULg; Fett, Thomas ULg; Baise, Etienne ULg et al

in Molecular Membrane Biology (2004), 21(5, Sep-Oct), 289-295

The leukocyte integrins play a critical role in a great number of cellular adhesive interactions during the immune response. We describe here the isolation and characterization of the caprine beta(2 ... [more ▼]

The leukocyte integrins play a critical role in a great number of cellular adhesive interactions during the immune response. We describe here the isolation and characterization of the caprine beta(2) (CD18) sub-unit, common to the leukocyte beta(2)-integrin family. The deduced 770-amino-acid sequence reveals a transmembrane protein with 80, 81, 83, 96 and 99% identity with its canine, murine, human, bovine and ovine homologues respectively. Analysis of CD18 sequences emphasizes the functional importance of the beta(2) sub-unit I-like domain, and included metal ion-dependent adhesion site-like motif and confirms that of the cytoplasmic tail. Moreover, comparisons of ruminant versus non-ruminant CD18 sequences allowed the identification of 16 potential mutation sites that could be held responsible for the unique virulence of Mannheimia haemolytica for ruminants. Mannheimiosis is known to be the major respiratory disease among ruminants, whereas it is not pathogenic for other mammals, an observation that has been attributed to a specific interaction between M. haemolytica leukotoxin and ruminants' CD18. Therefore, the data provided here offer the possibility to explore new avenues in studies based on the caprine model and provide key information for future studies aimed at elucidating the molecular mechanisms underlying the ruminant-specific virulence of M. haemolytica. [less ▲]

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See detailCharacterization of the cattle serum antibody responses against TEM beta-lactamase and the nonimmunogenic Escherichia coli heat-stable enterotoxin (STaI)
Zervosen, Astrid ULg; Saegerman, Claude ULg; Antoniotti, Ingrid et al

in FEMS Immunology & Medical Microbiology (2008), 54(3), 319-329

In order to test the use of a subunit recombinant vaccine for its capacity to induce antibodies against the nonimmunogenic heat-stable enterotoxin STa from Escherichia coli and the TEM-1 beta-lactamase ... [more ▼]

In order to test the use of a subunit recombinant vaccine for its capacity to induce antibodies against the nonimmunogenic heat-stable enterotoxin STa from Escherichia coli and the TEM-1 beta-lactamase, cattle were immunized with a hybrid protein created by insertion of the STa sequence at position 197 of the TEM-1 beta-lactamase. Specific anti-STa IgG and IgG1 antibodies were detected at low levels, while no IgG2 antibodies were detected. In contrast, high levels of the different anti-TEM IgG subtypes were detected in cattle sera. In addition, beta-lactamase activity was inhibited by the sera. The presence of antibodies against STa and TEM-1 beta-lactamase was assessed in sera from 366 cattle taken from the field. No significant level of IgGs against the toxin or the TEM-1 was detected. A comparison of the antibody level between the immunized and the nonimmunized animals clearly demonstrated that STa was not able to induce a significant level of antibodies in the vaccinated animals. In contrast, a strong antibody response against TEM-1 beta-lactamase was demonstrated. [less ▲]

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See detailCharacterization of the Chitin-Glucan Complex extracted from Komagataella Pastoris cell wall
Farinha, I; Duarte, P.; Pimentel, A. et al

Poster (2015)

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See detailCharacterization of the chitin-glucan complex extracted from Komagataella pastoris cell wall
Farinha, I.; Duarte, P.; Pimentel et al

in Proceeding of the meeting (2015, January 19)

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See detailCharacterization of the complete porcine MSTN gene and expression levels in pig breeds differing in muscularity.
Stinckens, A.; Luyten, T.; Bijttebier, J. et al

in Animal Genetics (2008), 39(6), 586-96

Myostatin (MSTN), a transforming growth factor beta superfamily member, is an essential factor for the growth and development of muscle mass. The protein functions as a negative regulator of muscle growth ... [more ▼]

Myostatin (MSTN), a transforming growth factor beta superfamily member, is an essential factor for the growth and development of muscle mass. The protein functions as a negative regulator of muscle growth and is related to the so-called double-muscling phenotype in cattle, where a series of mutations renders the gene inactive. One particular breed of pigs, the Belgian Pietrain, also shows a heavily muscled phenotype. The similarity of muscular phenotypes between the double-muscled cattle and Pietrain pigs indicated that MSTN may be a candidate gene for muscular hypertrophy in pigs. In this study, we sequenced and analysed the complete MSTN gene from 45 pigs of five different breeds, including the heavily muscled Pietrain breed at one extreme and the Meishan and Wild boar breeds at the other extreme. In total, 7626 bp of the porcine MSTN gene were sequenced, including the 5' and 3' UTR. Fifteen polymorphic loci were found, three of which were located in the promoter region, five in intron 1 and seven in intron 2. Most mutations were found when comparing the obtained MSTN sequence with porcine MSTN sequences already published. However, one polymorphism located at position 447 of the porcine MSTN promoter had a very high allele frequency in the Pietrain pig breed and disrupted a putative myocyte enhancer factor 3 binding site. Real-time PCR using Sybr Green showed that this mutation was associated with expression levels of the MSTN gene in m. longissimus dorsi at an age of 4 weeks. [less ▲]

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See detailCharacterization of the development of a behavioural sensitization in female Swiss mice
Didone, Vincent ULg; Quertemont, Etienne ULg

in Behavioural Pharmacology (2008), 19(5-6), 30-30

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See detailCharacterization of the DGAT1 K232A and variable number of tandem repeat polymorphisms in French dairy cattle.
Gautier, M.; Capitan, A.; Fritz, S. et al

in Journal of Dairy Science (2007), 90(6), 2980-8

A quantitative trait locus (QTL) underlying different milk production traits has been identified with a high significance threshold value in the genomic region containing the acylCoA:diacylglycerol ... [more ▼]

A quantitative trait locus (QTL) underlying different milk production traits has been identified with a high significance threshold value in the genomic region containing the acylCoA:diacylglycerol acyltransferase (DGAT1) gene, in the 3 main French dairy cattle breeds: French Holstein, Normande, and Montbeliarde. Previous studies have confirmed that the K232A polymorphism in DGAT1 is responsible for a major QTL underlying several milk production traits in Holstein dairy cattle and several other bovine breeds. In this study, we estimate the frequency of the 2 alternative alleles, K and A, of the K232A polymorphism in French Holstein, Normande, and Montbeliarde breeds. Although the K allele segregates in French Holstein and Normande breeds with a similar effect on production traits, the existence of additional mutations contributing to the observed QTL effect is strongly suggested in both breeds by the existence of sires heterozygous at the QTL but homozygous at the K232A polymorphism. One allele at a variable number of tandem repeats (VNTR) locus in the 5' noncoding region of DGAT1 has been recently proposed as a putative causative variant. In our study, this marker was found to present a high mutation rate of 0.8% per gamete and per generation, making the allele diversity observed compatible with that expected under neutrality. Moreover, among the sires homozygous at the K232A polymorphism, no allele at the VNTR can fully explain their QTL status. Finally, no allele at the VNTR was found to be significantly associated with the fat percentage variation in the 3 breeds simultaneously after correction for the effect of the K232A polymorphism. Therefore, our results suggest the existence of at least one other causative polymorphism not yet described. Because the A allele is nearly fixed in the Montbeliarde breed, this breed represents an interesting model to identify and confirm other mutations that have a strong effect on milk production traits. [less ▲]

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