Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailPumpellyite-(Al), a new mineral from Bertrix, Belgian Ardennes
Hatert, Frédéric ULg; Pasero, Marco; Perchiazzi, Natale et al

in European Journal of Mineralogy (2007), 19(2, MAR-APR), 247-253

Pumpellyite-(Al), ideally Ca-2(Al,Fe2+,Mg)Al-2(SiO4)(Si2O7)(OH,O)(2)center dot H2O, is a newly approved mineral species from Bertrix, Ardennes mountains, Belgium. It occurs as radiating fibrous aggregates ... [more ▼]

Pumpellyite-(Al), ideally Ca-2(Al,Fe2+,Mg)Al-2(SiO4)(Si2O7)(OH,O)(2)center dot H2O, is a newly approved mineral species from Bertrix, Ardennes mountains, Belgium. It occurs as radiating fibrous aggregates reaching 5 mm in diameter, constituted by acicular crystals associated with calcite, K-feldspar and chlorite. Pumpellyite-(Al) is transparent to translucent and exhibits an emerald-green to white colour, sometimes with bluish tinges. The lustre is vitreous and the streak is colourless. The mineral is non-fluorescent, brittle, and shows a perfect {100} cleavage. The estimated Mobs hardness is 51/2, and the calculated density is 3.24 g/cm(3). Pumpellyite-(Al) is biaxial positive, alpha = 1.678(2), beta = 1.680(2), gamma = 1.691 (1) (lambda = 590 nm), colourless in thin section, 2V = 46 degrees, Y = b, no dispersion. Electron-microprobe analyses gave SiO2 37.52, Al2O3 25.63, MgO 1.99, FeO 4.97, MnO 0.11, CaO 23.21, BaO 0.01, Na2O 0.03, K2O 0.02, H2Ocalc. 6.71, total 100.20 wt. %. The resulting empirical formula, calculated on the basis of 8 cations, is (Ca1.99Na0.01)(Sigma 2.00)(Al0.42Fe0.332+Mg0.24Mn0.01)(Sigma 1.00)Al-2.00(SiO4)(Si2O7)(2.42) center dot 0.58H(2)O. The simplified formula is Ca2AlAl2(SiO4)(Si2O7)(OH)(3), which requires SiO2 38.16, Al2O3 32.38, CaO 23.74, H2O 5.72, Total 100.00 wt. %. The unit-cell parameters, refined from X-ray powder diffraction data, are: a = 8.818(2), b = 5.898(2), c = 19.126(6) angstrom, beta = 97.26(3)degrees, V = 986.7(4) angstrom(3), space group A2/m. The eight strongest lines in the powder pattern [d-values(in angstrom)(I)(hkl)] are: 4.371(65)(200), 3.787(80)(202), 3.040(70)(204), 2.912(95)(300), 2.895(100)(30 (2) over bar), 2.731(40)(20 (6) over bar), 2.630(35)(31 (1) over bar), 2.191(45)(40 (2) over bar). Pumpellyite-(Al) belongs to the pumpellyite group, and corresponds to the Al-rich compositions where the M1 and M2 sites contain Al as predominant cation. The crystal structure of pumpellyite-(Al) has been refined by the Rietveld method, based on an X-ray powder diffraction pattern, to R-Bragg = 7.09 %. The infrared spectrum is similar to those of minerals of the pumpellyite group. The mineral species and name were approved by the Commission on New Minerals and Mineral Names, IMA (no. 2005-016). [less ▲]

Detailed reference viewed: 47 (1 ULg)
Full Text
Peer Reviewed
See detailPumping picosecond optical parametric oscillators by a pulsed Nd:YAG laser mode locked using a nonlinear mirror
Mani, A. A.; Dreesen, Laurent ULg; Hollander, Ph. et al

in Applied Physics Letters (2001), 79(13), 1945-1947

We report on the performances of the mode locking of a flash-lamp-pumped Nd:YAG laser using a frequency-doubling nonlinear mirror combined with a two-photon absorber. Pulse lengths from 12 to 8 ps are ... [more ▼]

We report on the performances of the mode locking of a flash-lamp-pumped Nd:YAG laser using a frequency-doubling nonlinear mirror combined with a two-photon absorber. Pulse lengths from 12 to 8 ps are generated. We show that the flat shape of the pulse-train envelope generated by the oscillator is adapted for the synchronous pumping of optical parametric oscillators and we demonstrate the efficient generation of an infrared beam tunable from 3800 to 1100 cm-1 with bandwidth of 2 cm-1 in one single conversion stage in LiNbO3 or AgGaS2. The "all-solid-state" laser system enables surface sum-frequency generation spectroscopy to be performed with high sensitivity and high resolution. [less ▲]

Detailed reference viewed: 25 (0 ULg)
Full Text
Peer Reviewed
See detailPunch Press Vibration Isolation: a Case History
Golinval, Jean-Claude ULg; Géradin, Michel ULg

in European Journal of Mechanical and Environmental Engineering (1999), 44(3), 141-145

Detailed reference viewed: 30 (0 ULg)
Full Text
Peer Reviewed
See detailPunctuation effects in english and esperanto texts
Ausloos, Marcel ULg

in Physica a-Statistical Mechanics and Its Applications (2010), 389(14), 2835-2840

A statistical physics study of punctuation effects on sentence lengths is presented for written texts: Alice in wonderland and Through a looking glass. The translation of the first text into esperanto is ... [more ▼]

A statistical physics study of punctuation effects on sentence lengths is presented for written texts: Alice in wonderland and Through a looking glass. The translation of the first text into esperanto is also considered as a test for the role of punctuation in defining a style, and for contrasting natural and artificial, but written, languages. Several log-log plots of the sentence-length-rank relationship are presented for the major punctuation marks. Different power laws are observed with characteristic exponents. The exponent can take a value much less than unity (ca. 0.50 or 0.30) depending on how a sentence is defined. The texts are also mapped into time series based on the word frequencies. The quantitative differences between the original and translated texts are very minutes, at the exponent level. It is argued that sentences seem to be more reliable than word distributions in discussing an author style. (C) 2010 Published by Elsevier B.V. [less ▲]

Detailed reference viewed: 5 (0 ULg)
Full Text
Peer Reviewed
See detailPupil light reflects in response to monochromatic light stimuli in younger and older subjects
Daneault, V; Vandewalle, Gilles ULg; Teikari, P et al

in Sleep (2011), 34(Suppl. 1),

Detailed reference viewed: 13 (2 ULg)
Full Text
Peer Reviewed
See detailPure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp
Bell, Ian ULg; Wronski, Jorrit; Quoilin, Sylvain ULg et al

in Industrial & Engineering Chemistry Research (2014), 53

Article Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp ACS ActiveView PDFHi-Res Print, Annotate, Reference QuickView PDF [2027 ... [more ▼]

Article Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp ACS ActiveView PDFHi-Res Print, Annotate, Reference QuickView PDF [2027 KB] PDF w/ Links[457 KB] Full Text HTML Abstract Supporting Info -> Figures Reference QuickView Add to ACS ChemWorx Ian H. Bell *†, Jorrit Wronski *‡, Sylvain Quoilin *†, and Vincent Lemort *† † Energy Systems Research Unit, University of Liège, Liège, Belgium ‡ Department of Mechanical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark Ind. Eng. Chem. Res., 2014, 53 (6), pp 2498–2508 DOI: 10.1021/ie4033999 Publication Date (Web): January 13, 2014 Copyright © 2014 American Chemical Society OpenURL UNIV DE LIEGE *E-mail: ian.bell@ulg.ac.be., *E-mail: jowr@mek.dtu.dk., *E-mail: squoilin@ulg.ac.be., *E-mail: vincent.lemort@ulg.ac.be. ACS AuthorChoice Abstract Over the last few decades, researchers have developed a number of empirical and theoretical models for the correlation and prediction of the thermophysical properties of pure fluids and mixtures treated as pseudo-pure fluids. In this paper, a survey of all the state-of-the-art formulations of thermophysical properties is presented. The most-accurate thermodynamic properties are obtained from multiparameter Helmholtz-energy-explicit-type formulations. For the transport properties, a wider range of methods has been employed, including the extended corresponding states method. All of the thermophysical property correlations described here have been implemented into CoolProp, an open-source thermophysical property library. This library is written in C++, with wrappers available for the majority of programming languages and platforms of technical interest. As of publication, 110 pure and pseudo-pure fluids are included in the library, as well as properties of 40 incompressible fluids and humid air. The source code for the CoolProp library is included as an electronic annex. [less ▲]

Detailed reference viewed: 43 (5 ULg)
Full Text
Peer Reviewed
See detail"Pure economic loss" en droit belge
Gerkens, Jean-François ULg

in Rapports belges au Congrès de l'Académie Internationale de Droit comparé à Utrecht (2006)

Detailed reference viewed: 23 (2 ULg)
Full Text
Peer Reviewed
See detailPure equilibrium tetrahedral finite elements for global error estimation by dual analysis
Kempeneers, Martin; Debongnie, Jean-François ULg; Beckers, Pierre ULg

in International Journal for Numerical Methods in Engineering (2010)

This study presents a general porocedure of creating pure equilibrium tetrahedral finite elements. These elements are of the Fraeijs de Veubeke type. The spurious kinematical modes which inevitably appear ... [more ▼]

This study presents a general porocedure of creating pure equilibrium tetrahedral finite elements. These elements are of the Fraeijs de Veubeke type. The spurious kinematical modes which inevitably appear in this approach are eliminated by converting each tetrahedron in a super-element consisting of four tetrahedral primitive elements. A mathematical discussion on the number of spurious kinematical modes is presented. The development of first and second degree elements is presented in detail, and their efficiency in the frame of global errror estimation by dual analysis is emphasized by two numerical applications. The main attribute of the error estimation by dual analysis is that it provides an upper bound of the discretization error. [less ▲]

Detailed reference viewed: 65 (6 ULg)
See detailLes pure players, un autre modèle journalistique
Colmant, François ULg

Scientific conference (2011, May 12)

Les pure players, un autre modèle journalistique Alors que la presse écrite traditionnelle francophone affronte depuis des années une sévère crise endémique et systémique, une alternative journalistique ... [more ▼]

Les pure players, un autre modèle journalistique Alors que la presse écrite traditionnelle francophone affronte depuis des années une sévère crise endémique et systémique, une alternative journalistique est apparue avec l’arrivée des pure players. Ces acteurs médiatiques, uniquement présents en ligne, dessinent les contours d’une autre presse et tendent à définir un nouveau modèle d’information de masse. Actifs depuis quelques années, ces sites, calqués à l’origine sur le modèle du Huffington Post (premier du genre), occupent désormais une réelle place médiatique et cultivent une approche de l’information et du journalisme volontairement différente des médias classiques, toujours adossés à un support papier. Aux prémices de la transition vers le paper free, cette nouvelle presse entend prendre à contre-courant l’ambition annoncée par plusieurs grands groupes de presse de modifier profondément la façon d’informer, où l’immédiateté serait érigée en règle d’or. Angles différents, actualités alternatives et investigation prononcée deviennent les maîtres mots d’un média essentiellement animé par d’historiques figures de la presse classique, associés à de jeunes journalistes pratiquement « nés » sur Internet. Gratuits ou payants, ces nouveaux médias, qui privilégient un autre rapport au lecteur et à l’information, gagnent petit à petit en reconnaissance mais peinent encore à se faire considérer comme l’égal de leurs cousins de papier. Malgré leur sérieux et leur rigueur, il semble que le support numérique, malgré son accessibilité accrue, souffre encore d’un profond déficit de légitimité auprès des caciques de la profession. Devant cet autre possible journalistique, notre approche consistera à interroger cette nouvelle donne, étudier son modèle économique – sensiblement différent – et questionner les changements concrets que cette approche induit sur le comportement et les conditions de travail, au quotidien, des journalistes. [less ▲]

Detailed reference viewed: 176 (19 ULg)
See detailLes pure players, une alternative journalistique
Colmant, François ULg

Scientific conference (2012, May 23)

Alors que la presse écrite traditionnelle francophone affronte depuis des années une sévère crise endémique et systémique, une alternative journalistique est apparue avec l’arrivée des pure players. Ces ... [more ▼]

Alors que la presse écrite traditionnelle francophone affronte depuis des années une sévère crise endémique et systémique, une alternative journalistique est apparue avec l’arrivée des pure players. Ces acteurs médiatiques, uniquement présents en ligne, dessinent les contours d’une autre presse et tendent à définir un nouveau modèle d’information de masse. Actifs depuis quelques années, ces sites, calqués à l’origine sur le modèle du Huffington Post (premier du genre), occupent désormais une réelle place médiatique et cultivent une approche de l’information et du journalisme volontairement différente des médias classiques, toujours adossés à un support papier. Aux prémices de la transition vers le paper free, cette nouvelle presse entend prendre à contre-courant l’ambition annoncée par plusieurs grands groupes de presse de modifier profondément la façon d’informer, où l’immédiateté serait érigée en règle d’or. Angles différents, actualités alternatives et investigation prononcée deviennent les maîtres mots d’un média essentiellement animé par d’historiques figures de la presse classique, associés à de jeunes journalistes pratiquement « nés » sur Internet. Gratuits ou payants, ces nouveaux médias, qui privilégient un autre rapport au lecteur et à l’information, gagnent petit à petit en reconnaissance mais peinent encore à se faire considérer comme l’égal de leurs cousins de papier. Malgré leur sérieux et leur rigueur, il semble que le support numérique, malgré son accessibilité accrue, souffre encore d’un profond déficit de légitimité auprès des caciques de la profession. Devant cet autre possible journalistique, notre approche consistera à interroger cette nouvelle donne, étudier son modèle économique – sensiblement différent – et questionner les changements concrets que cette approche induit sur le comportement et les conditions de travail, au quotidien, des journalistes. [less ▲]

Detailed reference viewed: 46 (2 ULg)
Full Text
Peer Reviewed
See detailPure red cell aplasia following peripheral stem cell transplantation: complete response to a short course of high-dose recombinant human erythropoietin.
Martelli, M.; Ponchio, L.; Beguin, Yves ULg et al

in Haematologica (1994), 79(5), 456-9

We studied a patient who developed pure red cell aplasia (PRCA) following peripheral stem cell transplantation for non-Hodgkin lymphoma. Serum erythropoietin was appropriate for the degree of anemia ... [more ▼]

We studied a patient who developed pure red cell aplasia (PRCA) following peripheral stem cell transplantation for non-Hodgkin lymphoma. Serum erythropoietin was appropriate for the degree of anemia. Corticosteroid treatment was ineffective. Four months after transplantation rHuEpo was administered subcutaneously at a dose of 150 U/Kg per day, five days a week for 8 weeks. Treatment induced an erythropoietic response and corrected anemia. Response was maintained following discontinuation of rHuEpo. This study and previous reports indicate that high doses of rHuEpo given over a short time can resolve PRCA following autologous or allogeneic stem cell transplantation. [less ▲]

Detailed reference viewed: 18 (0 ULg)
Full Text
Peer Reviewed
See detailPure species of grass discrimination with the help of hyperspectral imaging NIR
Dale, Laura ULg; Rotar, Ioan; Bogdan, Anca Dorina et al

in Agronomy Series of Scientific Research = Lucrari Stiintifice Seria Agronomie (2011, December), 54(2), 23-27

The possibilities to discriminate with hyperspectral imaging system, SWIR ImSpector N25E in grass mixtures of the pure species Festuca rubra L., Trifolium repens L., Agrostis capillaris L., Hieracium ... [more ▼]

The possibilities to discriminate with hyperspectral imaging system, SWIR ImSpector N25E in grass mixtures of the pure species Festuca rubra L., Trifolium repens L., Agrostis capillaris L., Hieracium aurantiacum L., Arnica montana L.was the objective of this study. All the samples were collected from natural meadows, from the National Apuseni Park, Apuseni Mountains, from Gârda area. The samples were naturally dried then prepared using the protocol for NIRS analyze. The model built with PLS–DA, was used to demonstrate wether the classes discrimination between pure species is possible or not. The goal of this study was to see in other images if the pure species are or are not recognized according to the spectral data base. The potential of using the Hyperspectral Imaging NIR (Camera NIR) to discriminate or to identify pure species was confirmed. For this technique the MatLab program was used .A percentage of more than 96% correct prediction for species discrimination was obtained. This study should drive to a more important point, which is to verify whether the toxic species are or are not used as food for animals in the natural meadows. The floristic composition of a meadow can be determined only if we have in the data base, dates for each identified species, as being part of the mix. [less ▲]

Detailed reference viewed: 34 (5 ULg)
Full Text
Peer Reviewed
See detailA purely distributed implementation of undervoltage load shedding
Otomega, Bogdan; Glavic, Mevludin; Van Cutsem, Thierry ULg

(2007, June)

A new design of load shedding against long-term voltage instability is proposed. It uses a set of distributed controllers, each monitoring a transmission voltage and controlling a group of loads. Each ... [more ▼]

A new design of load shedding against long-term voltage instability is proposed. It uses a set of distributed controllers, each monitoring a transmission voltage and controlling a group of loads. Each controller acts in closed-loop, shedding amounts that vary in magnitude and time according to the evolution of its monitored voltage. The whole system operates without information exchange between controllers, the latter being implicitly coordinated through network voltages. The operation, design and robustness of the proposed scheme are illustrated through a small but realistic example. [less ▲]

Detailed reference viewed: 54 (7 ULg)
Full Text
Peer Reviewed
See detailPurely Flavored Leptogenesis
Aristizabal Sierra, Diego ULg; Munoz, Luis Alfredo; Enrico, Nardi

in Physical Review D (2009), 80

We study a model for leptogenesis in which the total CP asymmetries in the decays and scatterings involving the SU(2) singlet seesaw neutrinos Nα vanish (ϵNα=0). Leptogenesis is possible due to ... [more ▼]

We study a model for leptogenesis in which the total CP asymmetries in the decays and scatterings involving the SU(2) singlet seesaw neutrinos Nα vanish (ϵNα=0). Leptogenesis is possible due to nonvanishing CP violating lepton flavor asymmetries, realizing a situation in which the baryon asymmetry is due exclusively to flavor effects. We study the production of a net lepton asymmetry by solving the Boltzmann equations specific to this model, and we show that successful leptogenesis can be obtained at a scale as low as the TeV. We also discuss constraints on the model parameter space arising from current experimental upper limits on lepton flavor violating decays. [less ▲]

Detailed reference viewed: 4 (1 ULg)
Full Text
See detailPurificacao, caracterizacao e dosagem radioimunologica de glicoproteinas associadas a gestacao em zebuinos
Melo de Sousa, Noelita ULg

Doctoral thesis (2002)

The pregnancy-associated glycoproteins (PAGs) constitute a large family of aspartic proteinases expressed in the outer epithelial cell layer of the Artyodactyla placenta. In the first part of the present ... [more ▼]

The pregnancy-associated glycoproteins (PAGs) constitute a large family of aspartic proteinases expressed in the outer epithelial cell layer of the Artyodactyla placenta. In the first part of the present work, two biochemical approaches were used to characterize PAGs isolated from zebu (Bos indicus) fetal cotyledons. The first procedure, used to isolate PAG from zebu placenta removed late in pregnancy, included extraction of proteins at neutral pH, acidic and ammonium sulfate precipitations, anion and cation exchange chromatographies. The second procedure, used to investigate PAG in placentas removed at early and mid gestational periods, included protein extractions at acid or alkaline pH followed by pepstatin-A agarose affinity chromatography. A bovine PAG radioimmunoassay was used to monitor the immunoreactivity throughout the isolation procedures. The most immunoreactive fractions issued from cation exchange and affinity chromatographies were analyzed by SDS-PAGE and Western Blot, before transfer to polyvinylidene difluoride (PVDF) membrane for NH2-microsequence determination. By use of SDS-PAGE and Western Blot, different isoforms of PAG with apparent molecular masses from 51 to 69 kDa and isoeletric points varying from 3.1 to 6.7 were identified in placentas from different gestational ages. After CM ceramic chromatography of all except 0.32 M NaCl DEAE fraction, the most immunoreactive proteins revealed N-terminal amino acid sequences (10 to 25 aa long) which were 100% identical to bovine PAG-1. The same sequence (14 aa long) was found after pepstatin-agarose affinity chromatography of proteins extracted from placentas removed earlier in pregnancy. These results converged towards the expression of one major N-terminal PAG amino acid sequence in zebu placentas at different gestational ages. In the second part of this study, two specific RIA systems were developed then used to measure plasmatic PAG concentrations during gestation and postpartum period in Azawak zebu cows. Twelve females palpated per rectum and diagnosed as pregnant were bled at 5-10 days interval approximately from Week 8 of gestation till Week 10 postpartum (pp). One zebu cow initially diagnosed as pregnant showed PAG concentrations lower than the assay sensitivity (<0.20 ng/ml) and did not calve. Another cow showed abnormally high PAG concentrations during gestation, being excluded from the general PAG profile. The 10 other zebu cows gave a very homogeneous PAG profile. In these animals, concentrations increased progressively from Week 8 to Week 35 of gestation (from 6.04.2 to 196.034.8 ng/ml), remaining relatively constant until Week 39 (210.874.8 ng/ml), when they increased sharply to reach their highest level (1,095.6607.2 ng/ml) at parturition. After delivery, PAG concentrations declined significantly (P<0.05) till the Week 2 postpartum (348.4  85.6 ng/ml) and slowly till the Week 10 postpartum. These results revealed that PAG concentrations in zebu cattle were lower than those previously described in taurine breeds between week 35 and 39 of gestation. [less ▲]

Detailed reference viewed: 54 (1 ULg)
See detailPurification and analysis by mass spectometry of low M.W. soluble factors released into conditioned culture media by B16 melanoma cells
Gillet, Marie-Claire ULg; Siwek, Brigitte; Quetin-Leclercq, Joelle et al

Poster (1995, July)

Detailed reference viewed: 24 (0 ULg)
Peer Reviewed
See detailPurification and Biochemical Characterization of Recombinant Human Placental Growth Hormone Produced in Escherichia Coli
Igout, Ahmed ULg; Van Beeumen, Jozef; Frankenne, Francis ULg et al

in Biochemical Journal (1993), 295(3), 719-724

The hGH-V (or hGH-2) gene codes for human placental growth hormone (hPGH). Secretion of hPGH is continuous, in contrast with the pulsed secretion of pituitary growth hormone (hGH) which it progressively ... [more ▼]

The hGH-V (or hGH-2) gene codes for human placental growth hormone (hPGH). Secretion of hPGH is continuous, in contrast with the pulsed secretion of pituitary growth hormone (hGH) which it progressively replaces in the maternal bloodstream. hGH- V cDNA has previously been cloned and isolated. Analysis of its nucleotide sequence has revealed a 191-residue protein, hPGH, differing from hGH at 13 positions. The calculated pI is more basic than that of the pituitary hormone. Here we have inserted hGH- VcDNA into the pIN-III-ompA3 plasmid in order to produce hPGH in its native form in Escherichia coli D1210. Expression of hGH- V cDNA in E. coli is significantly lower than that of hGH cDNA with the same expression system. The hPGH produced in E. coli was purified in quantities sufficient to allow its biochemical and immunochemical characterization. The molecular mass of the protein was determined by electrospray m.s. The determined mass, 22320 Da, agrees well with the molecular mass calculated from the translated cDNA sequence, assuming the presence of two disulphide bridges. Having established the technique for producing hPGH with a primary structure identical to the natural, non-glycosylated, 22 kDa isoform, we can now plan the full physicochemical and pharmaceutical characterization of this new hormonal entity. [less ▲]

Detailed reference viewed: 63 (19 ULg)
Full Text
Peer Reviewed
See detailPurification and characterisation of a 31 kDa chitinase from the Myzus persicae aphid, a target for Hemiptera biocontrol
Francis, Frédéric ULg; Saguez, Julien; Cherqui, Anas et al

in Applied Biochemistry and Biotechnology (2012), 166

Detailed reference viewed: 73 (20 ULg)
See detailPurification and characterisation of phage tail-like bacteriocin induced in Serratia sp.
Jabrane, A.; Vandenberghe, I.; Van beeumen, J. et al

Poster (1997, August)

Detailed reference viewed: 10 (1 ULg)
Full Text
Peer Reviewed
See detailPurification and Characterization of a 315 Kda Keratinolytic Subtilisin-Like Serine Protease from Microsporum Canis and Evidence of Its Secretion in Naturally Infected Cats
Mignon, Bernard ULg; Swinnen, M.; Bouchara, J. P. et al

in Medical Mycology (1998), 36(6), 395-404

A keratinolytic protease, secreted as the major component by a feline clinical isolate of Microsporum canis cultivated in a minimal medium containing cat keratin, was purified by affinity chromatography ... [more ▼]

A keratinolytic protease, secreted as the major component by a feline clinical isolate of Microsporum canis cultivated in a minimal medium containing cat keratin, was purified by affinity chromatography on bacitracin agarose and gel filtration. The apparent molecular mass of the enzyme was 31.5 kDa and the pI was 11.8. The enzyme was not glycosylated and its first 15 N-terminal amino acids showed numerous similarities with other fungal subtilisins. The optimum pH was around 9 while inactivation of the enzyme was reversible at pH 4, but not at pH 11. The enzyme was stable at 37 degrees C with an apparent optimum temperature around 55 degrees C. PMSF, soybean trypsin inhibitor (SBTI) and chymostatin strongly inhibited the proteinase. The highest affinity (Km of 0.37 mM) and physiological efficiency (k(cat)/Km) were obtained for the synthetic substrate N-Suc-Ala-Ala-Pro-Phe-p-nitroanilide. These results indicate that the keratinase belongs to the subtilisin-like serine protease family. Purified rabbit immunoglobulins G prepared against the keratinase and used in an immunohistochemical test allowed the detection of the keratinase produced by the fungus invading hair structures in naturally infected cats. The in vitro keratinolytic activity of the enzyme and its production in vivo suggest that it may contribute to pathogenicity. [less ▲]

Detailed reference viewed: 39 (5 ULg)