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See detailCharacterization of a new potential virulence factor of Microsporum canis, the secreted subtilisin Sub6
Mathy, Anne ULg; Baldo, Aline ULg; Salamin, K. et al

in Mycoses (2011), 54(suppl 2), 112-113

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See detailCharacterization of a novel aphid prenyltransferase displaying dual geranyl/farnesyl diphosphate synthase activity
Vandermoten, Sophie ULg; Charloteaux, Benoît ULg; Santini, S. et al

in FEBS Letters (2008), 582(16), 19281934

We report on the cDNA cloning and characterization of a novel short-chain isoprenyl diphosphate synthase from the aphid Myzus persicae. Of the three IPPS cDNAs we cloned, two yielded prenyltransferase ... [more ▼]

We report on the cDNA cloning and characterization of a novel short-chain isoprenyl diphosphate synthase from the aphid Myzus persicae. Of the three IPPS cDNAs we cloned, two yielded prenyltransferase activity following expression in Escherichia coli; these cDNAs encode identical proteins except for the presence, in one of them, of an N-terminal mitochondrial targeting peptide. Although the aphid enzyme was predicted to be a farnesyl diphosphate synthase by BLASTP analysis, rMpIPPS, when isopentenyl diphosphate and dimethylallyl diphosphate are supplied as substrates, typically generated geranyl diphosphate (C10) as its main product, along with significant quantities of farnesyl diphosphate (C15). Analysis of an MpIPPS homology model pointed to substitutions that could confer GPP/FPP synthase activity to the aphid enzyme. [less ▲]

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See detailCharacterization of a novel chitinase from a moderately halophilic bacterium, Virgibacillus marismortui strain M3-23
Essghaier, Badiaa; Hedi, Abdeljabbar; Bajji, Mohammed et al

in Annals of Microbiology (2012), 62(2), 835-841

A new chitinase produced by the moderately halophilic bacterium Virgibacillus marismortui strain M3- 23 was identified and characterized. Distinguishable characteristics of high activity and stability at ... [more ▼]

A new chitinase produced by the moderately halophilic bacterium Virgibacillus marismortui strain M3- 23 was identified and characterized. Distinguishable characteristics of high activity and stability at different pH, temperatures and salinity of M3-23 chitinase are reported. Analysis of the catalytic domain sequence from the enzyme highlighted its relationship to glycosyl hydrolase family 18. Comparison of the deduced chitinase sequence from strain M3-23 to known chitinases from Bacillus species showed low similarity (82%), suggested its novelty. This is the first report of the characterization of chitinase from the species V. marismortui. The halo- and thermo-tolerant nature of the chitinolytic enzyme allows its potential use in agricultural and industrial applications. [less ▲]

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See detailCharacterization of a novel circo-like virus in Aedes vexans mosquitoes from Germany: evidence for a new genus within the Circoviridae family.
Garigliany, Mutien-Marie ULg; Borstler, Jessica; Jost, Hanna et al

in The Journal of general virology (2014)

During the last decades, metagenomic studies expanded the numbers of newly described, often unclassified, viruses within the Circoviridae family. Using broad-spectrum circo-/cyclovirus PCRs, we ... [more ▼]

During the last decades, metagenomic studies expanded the numbers of newly described, often unclassified, viruses within the Circoviridae family. Using broad-spectrum circo-/cyclovirus PCRs, we characterized a novel circo-like virus in Aedes vexans mosquitoes from Germany whose main putative open reading frames (ORFs) shared very low amino acid identity with those of previously characterized circo-/cycloviruses. Phylogenetic and genetic distance analysis revealed that this new virus species defines, with previously described mosquito- and bat feces-derived circo-like viruses, a different genus, tentatively called "krikovirus", within Circoviridae. We further demonstrated that viruses of the putative krikovirus genus all share a genomic organization which is unique among Circoviridae. Further investigations are needed to determine the host range, tissue tropism and transmission route(s). This report increases the current knowledge of the genetic diversity and evolution of the members of the Circoviridae family. [less ▲]

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See detailCharacterization of a novel extended-spectrum TEM-type beta-lactamase, TEM-164, in a clinical strain of Klebsiella pneumoniae in Tunisia.
Ben Achour, Nahed; Mercuri, Paola ULg; Ben Moussa, Mohamed et al

in Microbial drug resistance (Larchmont, N.Y.) (2009), 15(3), 195-9

Klebsiella pneumoniae ML1708 exhibited a multiresistance phenotype, including resistance to all beta-lactams tested, chloramphenicol, ciprofloxacin, nalidixic acid, tetracycline, and streptomycin. The ... [more ▼]

Klebsiella pneumoniae ML1708 exhibited a multiresistance phenotype, including resistance to all beta-lactams tested, chloramphenicol, ciprofloxacin, nalidixic acid, tetracycline, and streptomycin. The double-disk synergy test was positive. ML1708 harbored a 50 kb conjugative plasmid that encoded a beta-lactamase of pI 5.5. The corresponding bla gene was identified by polymerase chain reaction and sequencing as a bla(TEM) gene. The deduced protein sequence revealed a new variant of TEM-1 beta-lactamase designated TEM-164. TEM-164 contains the unusual following mutations: L40V and I279T. These modifications may result in a change of the pI to 5.5 and hydrolyze cefotaxime and ceftazidime. [less ▲]

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See detailCharacterization of a novel freshwater gigartinalean red alga from Belize, with description of Sterrocladia belizeana sp. nov
Sherwood, AR; Necchi Jr, O; Carlile, AL et al

in Phycologia (2012), 51(6), 627-635

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See detailCharacterization of a novel IMP-28 metallo-β-lactamase from a Spanish Klebsiella oxytoca clinical isolate
Pérez-Llarena, FJ; Fernández, A; Zamorano, L et al

in Antimicrobial Agents and Chemotherapy (2012), 56(8), 4540-3

An isolate of Klebsiella oxytoca carrying a novel IMP metallo-β-lactamase was discovered in Madrid, Spain. The bla(IMP-28) gene is part of a chromosomally located class I integron. The IMP-28 k(cat)/K(m ... [more ▼]

An isolate of Klebsiella oxytoca carrying a novel IMP metallo-β-lactamase was discovered in Madrid, Spain. The bla(IMP-28) gene is part of a chromosomally located class I integron. The IMP-28 k(cat)/K(m) values for ampicillin, ceftazidime, and cefepime and, to a lesser extent, imipenem and meropenem, are clearly lower than those of IMP-1. The His306Gln mutation may induce important modifications of the L3 loop and thus of substrate accessibility and hydrolysis and be the main reason for this behavior. [less ▲]

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See detailCHARACTERIZATION OF A NOVEL RADIOTRACER TARGETING SYNAPTIC VESICLE PROTEIN 2A (SV2A)
Warnock, Geoffrey ULg; Aerts, Joël ULg; Bahri, Mohamed Ali ULg et al

Poster (2012, September)

Synaptic vesicle protein 2A (SV2A) has been identified as the binding site of the antiepileptic levetiracetam (Keppra) [1]. SV2 proteins are critical for proper nervous system function and have been ... [more ▼]

Synaptic vesicle protein 2A (SV2A) has been identified as the binding site of the antiepileptic levetiracetam (Keppra) [1]. SV2 proteins are critical for proper nervous system function and have been demonstrated to be involved in vesicle trafficking. Their implication in epilepsy makes them an interesting therapeutic target, and the widespread distribution of SV2A in particular may provide an opportunity to develop a PET-based measure of neuronal function in brain diseases. [18F]UCB-H is a fluorine-18 radiolabelled PET imaging agent with a nanomolar affinity for the human SV2A protein. Preclinical PET studies in rodents were carried out using male SD rats, imaged under isoflurane anaesthesia in a Siemens Concorde Focus 120 microPET scanner. Arterial input function was measured using an arteriovenous shunt method and beta microprobe system. [18F]UCB-H was injected IV (3.8 ± 0.54 mCi bolus, specific activity 8.5 ± 0.86 Ci/Emol immediately after synthesis) and dynamic PET data acquired in list mode for 90 min. Images were reconstructed using filtered back projection with correction for all physical effects except scatter. These scans revealed high uptake of [18F]UCB-H in brain and spinal cord, matching the expected homogeneous distribution of SV2A in the rodent brain [2]. Notably, the kinetics of [18F]UCB-H uptake in the brain were fast, peaking at up to 30 % ID/cm3 before a rapid decline. Metabolism of [18F]UCB-H in vivo followed a typical pattern of rapid initial metabolism followed by a reducing rate of metabolism over time, with less than 20% of the activity in plasma attributable to the parent compound after 30 minutes, and was highly reproducible between subjects. One major metabolite was identified. The uptake of [18F]UCB-H in the brain over time was well fitted by a classical 1-tissue compartment model. Mean parameter estimates (mean ± SD, n=7, whole brain VOI) were K1: 3.58 ± 0.65 ml/cm3/min, k2: 0.21 ± 0.03 min-1, Vt: 17.21 ± 2.52 ml/cm3. Uptake of [18F]UCB-H was blocked by pretreatment with brivaracetam (21 mg/kg IV, 10 min prior to [18F]UCB-H), a recently described high affinity SV2A ligand with a 20-fold higher affinity for SV2A than levetiracetam [3]. In contrast, pretreatment with ucb-100230-1, a diastereoisomer of brivaracetam with 3200-fold lower affinity for SV2A [3], had no clear effect of the brain uptake of [18F]UCB-H. Our results indicate that [18F]UCB-H is a suitable radiotracer for the quantification of SV2A proteins in vivo and for estimating target occupancy of drugs targeting SV2A. This is the first PET tracer for in vivo quantification of SV2A. The necessary steps for implementation of [18F]UCB-H production under GMP conditions have been completed and first in human studies are planned. References [1] Lynch, B.A. et al. (2004) PNAS 101(26):9861-6. [2] Janz, R. & Sudhof, T.C. (1999) Neuroscience 94(4):1279-1290.[3] Gillard, M. et al. (2011) Eur J Pharmacol 664:36-44. [less ▲]

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See detailCharacterization of a population of the Harlequin crab, Lissocarcinus orbicularis Dana, 1852, an obligate symbiont of holothuroids, in Toliara bay (Madagascar)
Caulier, Guillaume; Parmentier, Eric ULg; Lepoint, Gilles ULg et al

in Zoosymposia (2012), 7

Harlequin crabs, Lissocarcinus orbicularis, are commensals found on the integument and in the buccal/cloacal cavity of several species of holothuroids. The population of these crabs was investigated on ... [more ▼]

Harlequin crabs, Lissocarcinus orbicularis, are commensals found on the integument and in the buccal/cloacal cavity of several species of holothuroids. The population of these crabs was investigated on holothuroids of the barrier reef of Toliara (South-West of Madagascar) from 2002 to 2008. Seventeen holothuroid species were observed and eight were crab hosts. There is generally one adult crab or a heterosexual pair per infested holothuroid but up to ten juveniles were recorded on a Thelenota ananas. Carapace length of the observed L. orbicularis was from 0.3 to 1.4 cm from the tip of the rostrum to the end of the cephalothorax, with a mean length of 0.85 cm. L. orbicularis is characterized by a weak sexual dimorphism (females are bigger than males) and the presence of pereiopods morphologically adapted to fixation on the host integument. Gravid females were observed at each month of the survey indicating that the crab reproduces all the year. Considering our results and personal observations, we also discuss the monogamy mating system of the Harlequin crab. [less ▲]

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See detailCharacterization of a recombinant fusion protein of the finger domain of tissue-type plasminogen activator with a truncated single chain urokinase-type plasminogen activator.
Gheysen, D.; Lijnen, H. R.; Pierard, Luc ULg et al

in The Journal of biological chemistry (1987), 262(24), 11779-84

Human recombinant single chain urokinase-type plasminogen activator (recombinant scu-PA) and a hybrid between human tissue-type plasminogen activator (t-PA) and scu-PA, obtained by ligation of cDNA ... [more ▼]

Human recombinant single chain urokinase-type plasminogen activator (recombinant scu-PA) and a hybrid between human tissue-type plasminogen activator (t-PA) and scu-PA, obtained by ligation of cDNA fragments encoding the NH2-terminal region (amino acids 1-67) of t-PA and the COOH-terminal region (amino acids 136-411) of scu-PA, were expressed in a mammalian cell system. The proteins were purified from conditioned culture media containing 2% fetal calf serum by chromatography on zinc chelate-Sepharose, immunoadsorption chromatography on an insolubilized murine monoclonal antibody directed against urokinase, benzamidine-Sepharose chromatography, and Ultrogel AcA 44 gel filtration. Between 180 and 230 micrograms of the purified proteins were obtained per liter of conditioned medium, with a yield of approximately 18% and a purification factor of 720-1900. On sodium dodecyl sulfate gel electrophoresis under reducing conditions, the proteins migrated as single bands with approximate Mr 50,000 for recombinant scu-PA and Mr 43,000 for the t-PA/scu-PA hybrid. Following conversion to urokinase with plasmin, the proteins had a specific amidolytic activity comparable to that of natural scu-PA. Both proteins activated plasminogen directly with Km = 0.53 and 1.4 microM and k2 = 0.0034 and 0.0027 s-1, respectively. Both proteins did not bind specifically to fibrin and had a comparable degree of fibrin selectivity as measured in a system composed of a whole human 125I-fibrin-labeled plasma clot suspended in human plasma. It is concluded that this chimeric protein, consisting of the NH2-terminal "finger-like" domain of t-PA and the COOH-terminal region of scu-PA, has very similar enzymatic properties as compared to scu-PA, but has not acquired the fibrin affinity of t-PA. [less ▲]

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See detailCharacterization of a scroll compressor under extended operating conditions
Cuevas, Cristian; Lebrun, Jean ULg; Lemort, Vincent ULg et al

in Applied Thermal Engineering (2010), 30

Refrigeration and air-conditioning compressors are designed to work under well-defined conditions. In some applications it is interesting to observe their performances beyond these conditions, for example ... [more ▼]

Refrigeration and air-conditioning compressors are designed to work under well-defined conditions. In some applications it is interesting to observe their performances beyond these conditions, for example in the case of a high temperature two-stage heat pump or of a cooling system working at high temperature. In this study a compressor is characterized experimentally with refrigerant R134a and through 118 tests at condensing pressures varying from 8.6 up to 40.4 bar (tsat = 33.9°C to tsat = 100.8°C) and evaporating pressures varying from 1.6 up to 17.8 bar (tsat = -15.6°C to tsat = 62.4°C). Under these conditions the compressor motor was pushed at its maximal current in several tests. This compressor’s performance is mainly characterized by its isentropic and volumetric efficiencies. It presents a maximal isentropic efficiency of 72%, corresponding to a pressure ratio of around 2.5–2.6. The volumetric efficiency decreases linearly from almost 1.0 (for a pressure ratio of 1.3) to 0.83 (for a pressure ratio of 9.7). A slight degradation of the isentropic and volumetric efficiencies is observed when the compressor supply and exhaust pressures are increased for a given pressure ratio; this could be due to an internal leakage. The compressor tests are used to identify the six parameters of a semi-empirical simulation model. After parameter identification, experimental and simulated results are in very good agreement, except for some points at high compressor power where the compressor is pushed at its maximal current. [less ▲]

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See detailCharacterization of a set of variable number of tandem repeat markers conserved in Bovidae
Georges, Michel ULg; Gunawardana, A.; Threadgill, D. et al

in Genomics (1991), 11(1), 24-32

Screening purpose-built libraries with minisatellite probes, we have isolated 36 bovine variable number of tandem repeat markers (VNTRs) characterized by a mean heterozygosity of 59.3 within the American ... [more ▼]

Screening purpose-built libraries with minisatellite probes, we have isolated 36 bovine variable number of tandem repeat markers (VNTRs) characterized by a mean heterozygosity of 59.3 within the American Holstein breed. Matching probabilities and exclusion powers were estimated by Monte-Carlo simulation, showing that the top 5 to 10 markers could be used as a very efficient DNA-based system for individual identification and paternity diagnosis. The isolated VNTR systems should contribute significantly to the establishment of a bovine primary DNA marker map. Linkage analysis, use of somatic cell hybrids, and in situ hybridization demonstrate that these bovine VNTRs are scattered throughout the bovine genome, without evidence for proterminal confinement as in the human, and that at least some of them are organized as clusters. Moreover, Southern blot analysis and in situ hybridization demonstrate conservation of sequence and map location of minisatellites within Bovidae [less ▲]

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See detailCharacterization of a single prolactin (PRL) receptor in tilapia (Oreochromis niloticus) which binds both PRLI and PRLII
Auperin, B.; Rentier-Delrue, Françoise ULg; Martial, Joseph ULg et al

in Journal of Molecular Endocrinology (1994), 13(3), 241-51

In tilapia, there are two forms of prolactin (PRL) whose effects on sodium and chloride movements differ and depend on the living environment of the fish. To see whether different receptors or the same ... [more ▼]

In tilapia, there are two forms of prolactin (PRL) whose effects on sodium and chloride movements differ and depend on the living environment of the fish. To see whether different receptors or the same receptor mediates these different effects, we have characterized the specific binding of both forms of tilapia (ti)PRL in two osmoregulatory organs, the gill and kidney. Two recombinant tiPRLs were used for this analysis. The recombinant hormones had the same properties as the native hormones in a tilapia gill radioreceptor assay. Specific binding to gill and kidney membranes was increased by optimizing the quality of the tissue preparations (physiological state of fish, membrane preparation) and the incubation conditions (pH, salt concentrations, temperature, time). Under these optimized conditions, we detected only one class of high affinity PRL receptor in gill and kidney. Its binding affinity was higher for tiPRLI than for tiPRLII in both gill and kidney (for tiPRLI the respective affinity values were 2.9 and 2.3 x 10(10) per M, for tiPRLII they were 1.9 and 0.5 x 10(10) per M). In competition studies, tiPRLI was more potent, followed by tiPRLII and ovine (o)PRL. tiGH and oGH did not significantly displace either tiPRL. The receptor we have characterized thus recognizes quite specifically both tiPRLs. [less ▲]

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See detailCharacterization of a single strong tissue-specific enhancer downstream from the three human genes encoding placental lactogen
Jacquemin, Patrick; Oury, Cécile ULg; Peers, Bernard ULg et al

in Molecular & Cellular Biology (1994), 14(1), 93-103

The human genes coding for growth hormone (hGH) and placental lactogen (choriosomatomammotropic hormone [hCS]) are clustered on chromosome 17 in the following order: 5' hGH-N hCS-L hCS-A hGH-V hCS-B 3 ... [more ▼]

The human genes coding for growth hormone (hGH) and placental lactogen (choriosomatomammotropic hormone [hCS]) are clustered on chromosome 17 in the following order: 5' hGH-N hCS-L hCS-A hGH-V hCS-B 3'. So far, a single placenta-specific enhancer has been identified in the locus, 2 kb downstream from the hCS-B gene, and shown to comprise one in vitro binding site for a nuclear protein. We here provide evidence that the hCS-B enhancer is more complex: (i) protection against DNase I digestion in the 3' flanking region of the hCS-B gene reveals four binding sites (DF-1, DF-2, DF-3, and DF-4) for nuclear proteins from either placental or HeLa cells, and (ii) placenta-specific enhancer activity can be fully exerted in transient expression experiments by a 126-bp fragment comprising the DF-3 and DF-4 protein-binding sites. By dissecting this region, we show that enhancer activity is mediated by a synergy between DF-3 and DF-4. Competitions with various oligonucleotides in footprinting and gel retardation experiments indicate that the same protein or set of proteins, different in HeLa and placenta cell nuclei, interacts with sites DF-2, DF-3, and DF-4. We also studied the regions of the hCS-L and hCS-A genes which are highly similar to the hCS-B enhancer. Although they each present the same four protein-binding sites, they exhibit only minor enhancer activity. [less ▲]

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See detailCharacterization of acetification enzymes from thermotolerant acetic acid bacteria, Acetobacter pasteurianus VM 136.
Mouanda, P.; Thonart, Philippe ULg; Tanazefti, H. et al

in Mededelingen Faculteit Landbouwkundige en Toegepaste Biologische Wetenschappen Universiteit Gent (1999), 64(5a),

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See detailCharacterization of Adulteration of "Espinheira Santa" ( Maytenus ilicifolia and Maytenus aquifolium, Celastraceae) Hydroalcoholic Extracts with Sorocea bomplandii ( Moraceae) by High-Performance Thin Layer Chromatography
Vilegas, Janete H.Y.; Lanças, Fernando M.; Wauters, Jean-Noël ULg et al

in Phytochemical Analysis (1998), 9

A HPTLC procedure for the characterization of adulteration of " espinheira santa ( Maytenus sp) with Sorocea bomplandii by monitoring their flavonoid content with the aid of diphenylboric reagent, is ... [more ▼]

A HPTLC procedure for the characterization of adulteration of " espinheira santa ( Maytenus sp) with Sorocea bomplandii by monitoring their flavonoid content with the aid of diphenylboric reagent, is presented. HPTLC data showed the predominance of higly glycosated quercetin and kaempferol derivatives. The derivated flavonoids were shown to be best markers for distinguishing between authentic and adulterated drug samples, with several advantages over triterpene analysis [less ▲]

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