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See detailMembrane-bound DD-carboxypeptidase and LD-transpeptidase of Streptococcus faecalis ATCC 9790
Coyette, Jacques; Perkins, Harnold R.; Polacheck, Itzhack et al

in European Journal of Biochemistry (1974), 44(2), 459-468

Isolated membranes of Streptococcus faecalis ATCC 9790 exhibit DD-carboxypeptidase activity (standard reaction: Ac2-l-Lys-d-Ala-d-Ala →d-alanine + Ac2-l-Lys-d-Ala) and ld-trans-peptidase activity ... [more ▼]

Isolated membranes of Streptococcus faecalis ATCC 9790 exhibit DD-carboxypeptidase activity (standard reaction: Ac2-l-Lys-d-Ala-d-Ala →d-alanine + Ac2-l-Lys-d-Ala) and ld-trans-peptidase activity (standard reaction: Ac2-l-Lys-d-Ala + acceptor →d-alanine + Ac2-l-Lys-acceptor). The DD-carboxypeptidase activity has a considerable specificity for peptides with a C-terminal l-R3-d-Ala-d-Ala sequence where R3 is an amino acid residue and a long side-chain at the l-R3 position. A corresponding DD-transpeptidation reaction yielding the product Ac2-l-Lys-d-Ala-d-[14C]Ala from the system Ac2-l-Lys-d-Ala-d-Ala-f-d-[14C] alanine was not detected. The ld-transpeptidase activity has a considerable specificity for peptide donors that have an Nα-substituted, C-terminal l-R3-d-Ala sequence with a free ω-amino group at the end of a long side-chain at the l-R3 position, and a considerable specificity for amino group acceptors that are located on a d-carbon in α-position to a free carboxyl group. In the absence of acceptor, hydrolysis of the dipeptide Ac2-l-Lys-d-Ala (ld-carboxypeptidase activity) was not observed. Both DD-carboxypeptidase and ld-transpeptidase activities are inhibited by β-lactam antibiotics, but their relative sensitivity differs according to the particular antibiotic used. [less ▲]

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See detailMembrane-bound transpeptidase and penicillin binding sites in Streptomyces strain R61
Marquet, Alberto; Dusart, Jean; Ghuysen, Jean-Marie ULg et al

in European Journal of Biochemistry (1974), 46(3), 515-523

High-affinity penicillin binding sites from which the antibiotic could not be removed by washings at 4°C in 0.017 M K2HPO4 or 0.05 M Tris-HCl pH 7.5, were shown to occur in the isolated membranes of ... [more ▼]

High-affinity penicillin binding sites from which the antibiotic could not be removed by washings at 4°C in 0.017 M K2HPO4 or 0.05 M Tris-HCl pH 7.5, were shown to occur in the isolated membranes of Streptomyces R61. These sites caused the attachment of 25 picomoles of [14C]benzylpenicillin per milligram membrane protein. Penicillins and cephalosporins competed for the same binding sites. The antibiotic concentrations which excluded [14C]benzylpenicillin from 50% of the binding sites were those which inhibited by 50% the membrane-bound transpeptidase. The same rate constant (about 1 × 10−4 s−1) for the dissociation of the benzylpenicillin membrane complex at 37°C and in 0.017 M K2HPO4, was calculated either from the release of the radioactivity (using [14C]benzylpenicillin) or from the recovery of the transpeptidase activity. These observations supported the conclusion that the high-affinity binding sites in the isolated membranes were the transpeptidase molecules. All the complexes formed between the membranes and the various penicillins and cephalosporins examined were reversible at 37°C and in 0.017 M K2HPO4 at least with regard to the transpeptidase. Depending upon the antibiotics, the rate constants for the dissociation of these complexes varied from 3.3 × 10−3 to 0.73 × 10−4 s−1. The radioactivity released through the dissociation of [14C]benzylpenicillin membrane complex occurred mainly in the form of a compound which behaved as [W]-benzylpenicilloic acid both by paper electrophoresis and thin-layer chromatography. It was impossible to choose between several possible mechanisms for the release of the antibiotic molecule. [less ▲]

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See detailMembrane-type 1 matrix metalloproteinase expression is regulated by zonula occludens-1 in human breast cancer cells
Polette, M.; Gilles, Christine ULg; Nawrocki-Raby, B. et al

in Cancer Research (2005), 65(17), 7691-7698

The acquisition of a migratory/invasive phenotype by tumor cells is characterized by the loss of cell-cell adhesion contacts and the expression of degradative properties. In this study, we examined the ... [more ▼]

The acquisition of a migratory/invasive phenotype by tumor cells is characterized by the loss of cell-cell adhesion contacts and the expression of degradative properties. In this study, we examined the effect of the disorganization of occludin/zomda occludens (ZO)-1 tight junction (TJ) complexes on the expression of membrane-type I matrix metalloproteinase (MT1-MMP). We first compared the expression of MT1-MMP and the localization of occludin/ZO-1 complexes in breast tumor cell lines displaying various degrees of invasiveness. We showed that the expression of MT1-MMP in invasive breast tumor cell lines correlates with the absence of occludin and with a cytoplasmic localization of ZO-1. In contrast, noninvasive cell lines displayed a membrane staining for both ZO-1 and occludin and did not express MT1-MMP. In vivo, cytoplasmic ZO-1 and MTI-MMP could be detected in invasive tumor clusters of human breast carcinomas. We then used RNA interference strategy to inhibit ZO-1 expression in invasive BT549 cells and to evaluate the effect of ZO-1 downregulation on MTI-MMP expression. We observed that ZO-1 small interfering RNA transfection down-regulates MT1-MMP mRNAs and proteins and subsequently decreases the ability of tumor cells to invade a reconstituted basement membrane in a Boyden chamber assay. Inversely, transfection of expression vectors encoding wild-type ZO-1 or the NH2-terminal fragment of ZO-1 comprising the PSD95/DLG/ZO-1 domains in BT549 activated a human MT1-MMP promoter luciferase reporter construct and increased cell invasiveness. Such transfections concomitantly activated the beta-catenin/TCF/LEF pathway. Our results therefore show that ZO-1, besides its structural role in TJ assembly, can intervene in signaling events promoting tumor cell invasion. [less ▲]

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See detailMembrane-Type 4 Matrix Metalloproteinase (MT4-MMP) induces lung metastasis by alteration of primary breast tumor vascular architecture
Chabottaux, Vincent; Ricaud, Stéphanie; Host, Lorin et al

in Journal of Cellular & Molecular Medicine (2009)

The present study aims at investigating the mechanism by which MT4-MMP, a membrane-anchored MMP expressed by human breast tumor cells promotes the metastatic dissemination into lung. We applied ... [more ▼]

The present study aims at investigating the mechanism by which MT4-MMP, a membrane-anchored MMP expressed by human breast tumor cells promotes the metastatic dissemination into lung. We applied experimental (intravenous) and spontaneous (subcutaneous) models of lung metastasis using human breast adenocarcinoma MDA-MB-231 cells overexpressing or not MT4-MMP. We found that MT4-MMP does not affect lymph node colonization nor extravasation of cells from the bloodstream, but increases the intravasation step leading to metastasis. Ultrastructural and fluorescent microscopic observations coupled with automatic computer-assisted quantifications revealed that MT4-MMP expression induces blood vessel enlargement and promotes the detachment of mural cells from the vascular tree, thus causing an increased tumor vascular leak. On this basis, we propose that MT4-MMP promotes lung metastasis by disturbing the tumor vessel integrity and thereby facilitating tumor cell intravasation. [less ▲]

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See detailMembrane-type 4 matrix metalloproteinase promotes breast cancer growth and metastases
Chabottaux, Vincent; Sounni, Nor Eddine ULg; Pennington, C. J. et al

in Cancer Research (2006), 66(10), 5165-5172

Membrane-type matrix metalloproteinases (MT-MMP) constitute a subfamily of six distinct membrane-associated MMPs. Although the contribution of MT1-MMP during different steps of cancer progression has been ... [more ▼]

Membrane-type matrix metalloproteinases (MT-MMP) constitute a subfamily of six distinct membrane-associated MMPs. Although the contribution of MT1-MMP during different steps of cancer progression has been well documented, the significance of other MT-MMPs is rather unknown. We have investigated the involvement of MT4-MMP, a glycosylphosphatidylinositol-anchored protease, in breast cancer progression. Interestingly, immunohistochemical analysis shows that MT4-MMP production at protein level is strongly increased in epithelial cancer cells of human breast carcinomas compared with normal epithelial cells. Positive staining for MT4-MMP is also detected in lymph node metastases. In contrast, quantitative reverse transcription-PCR analysis reveals similar MT4-MMP mRNA levels in human breast adenocarcinomas and normal breast tissues. Stable transfection of MT4-MMP cDNA in human breast adenocarcinoma MDA-MB-231 cells does not affect in vitro cell proliferation or invasion but strongly promotes primary tumor growth and associated metastases in RAG-1 immunodeficient mice. We provide for the first time evidence that MT4-MMP overproduction accelerates in vivo tumor growth, induces enlargement of i.t. blood vessels, and is associated with increased lung metastases. These results identify MT4-MMP as a new putative target to design anticancer strategies. [less ▲]

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See detailMembrane-type matrix metalloproteinase-1 expression at the site of human placentation
Nawrocki, B.; Polette, M. E.; Marchand, V. et al

in Placenta (1996), 17(8), 565-72

Human trophoblast implantation is a highly regulated process of invasion that requires action of proteolytic enzymes to degrade extracellular matrix components of the endometrium. Among these enzymes ... [more ▼]

Human trophoblast implantation is a highly regulated process of invasion that requires action of proteolytic enzymes to degrade extracellular matrix components of the endometrium. Among these enzymes, matrix metalloproteinases (MMPs) seem to be particularly important in this degradative process. We previously showed that gelatinase A is extensively expressed in vivo in the human placenta. A new MMP, MT-MMP-1 (membrane-type matrix metalloproteinase-1), which is thought to activate progelatinase A, has recently been described. In this study, we examined the expression of MT-MMP-1, by immunohistochemistry and in situ hybridization, in human placental bed biopsies taken during the first trimester of gestation. Human first trimester intermediate trophoblasts synthesized MT-MMP-1 mRNAs and the protein. The MT-MMP-1 pattern of distribution in placental beds was similar to that of gelatinase A, suggesting a pivotal role for MT-MMP-1 in placentation, perhaps by activating progelatinase A. [less ▲]

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See detailmembre rebelle
Claes, Hubert; Andrianne, Robert ULg

Book published by Roularta Books (2005)

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See detailMême galvaudé, le terme ‘politique’ ne suggère-t-il pas le pouvoir ?
Grandjean, Geoffrey ULg

Conference given outside the academic context (2012)

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See detailMême le silence a une fin
Claisse, Frédéric ULg

Article for general public (2011)

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See detailMémento de conception mécanique
Debongnie, Jean-François ULg

Book published by DEBONGNIE (JEAN-FRANCOIS) (2013)

Normal numbers. Tolerances. Alloy designation. Antifriction bearings. Journal bearings. Assembling of a shaft and a hub. Bolts. Welds. Riveted joints. Shafts. Fatigue. Hertzian contacts. Wear. Belts ... [more ▼]

Normal numbers. Tolerances. Alloy designation. Antifriction bearings. Journal bearings. Assembling of a shaft and a hub. Bolts. Welds. Riveted joints. Shafts. Fatigue. Hertzian contacts. Wear. Belts. Gearings. Illustrated lexicon. [less ▲]

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See detailMemento of useful tips and tricks for HP50g
Merciadri, Luca ULg

E-print/Working paper (2009)

This document presents a short list of math. important commands on HP50g. There is not much documentation about HP50g on Internet, so it completes the user’s manual.

Detailed reference viewed: 302 (18 ULg)
See detailMémoire
Brédart, Serge ULg; Van der Linden, Martial ULg

in Rondal, Jacques (Ed.) Introduction à la psychologie scientifique (1999)

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See detailMémoire à ciel ouvert. Une histoire de l’Espagne : 1931-1981
Molina Marmol, Maïté ULg; Muñoz, Ángeles

Book published by Territoires de la Mémoire (2014)

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See detailMémoire à court terme et pathologies du langage
Poncelet, Martine ULg; Majerus, Steve ULg; Van der Linden, Martial ULg

in Rééducation Orthophonique (2001), 208

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See detailMémoire à court terme verbale : cause ou conséquence du développement du langage ?
Majerus, Steve ULg; Poncelet, Martine ULg

in Metz-Lutz, M. (Ed.) Développement cognitif et troubles des apprentissages : évaluer, comprendre, rééduquer et prendre en charge (2004)

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See detailMémoire à court terme verbale et développement lexical chez l'enfant normal et l'enfant avec troubles spécifiques du langage
Majerus, Steve ULg; Poncelet, Martine ULg

in Hommet, C. (Ed.) Neuropsychologie de l'enfant et troubles du développement (2005)

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See detailMémoire associative dans le vieillissement normal : Effet de l’unification des associations
Simon, Jessica ULg; Collette, Fabienne ULg; Genon, Sarah ULg et al

in Proceedings of the XIIème Colloque International sur le Vieillissement Cognitif (2012)

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See detailMémoire de concours sur la torsion: rapport de F. Folie
Folie, François ULg

in Bulletins de l'Académie Royale des Sciences, des Lettres et des Beaux-Arts de Belgique (1879), 2e série, t. 48(12), 594-598

The author summurizes a thesis about the torsion and analyzes the different parts.

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See detailLa mémoire de la Révolution française en Belgique. Entre Liège et Wallonie.
Raxhon, Philippe ULg

Book published by Labor (1996)

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