References of "Ruysschaert, Jm"
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See detailSequence-optimised E2 constructs from BVDV-1b and BVDV-2 for DNA immunisation in cattle
Couvreur, B.; Letellier, C.; Olivier, Fabrice ULg et al

in Veterinary Research (2007), 38(6, NOV-DEC), 819-834

We report DNA immunisation experiments in cattle using plasmid constructs that encoded glycoprotein E2 from bovine viral diarrhoea virus (BVDV)-1 (E2.1) and BVDV-2 (E2.2). The coding sequences were ... [more ▼]

We report DNA immunisation experiments in cattle using plasmid constructs that encoded glycoprotein E2 from bovine viral diarrhoea virus (BVDV)-1 (E2.1) and BVDV-2 (E2.2). The coding sequences were optimised for efficient expression in mammalian cells. A modified leader peptide sequence from protein gD of BoHV1 was inserted upstream of the E2 coding sequences for efficient membrane export of the proteins. Recombinant E2 were efficiently expressed in COS7 cells and they presented the native viral epitopes as judged by differential recognition by antisera from cattle infected with BVDV-1 or BVDV-2. Inoculation of pooled plasmid DNA in young cattle elicited antibodies capable of neutralising viral strains representing the major circulating BVDV genotypes. [less ▲]

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See detailThe precursor of a psychrophilic alpha-amylase: structural characterization and insights into cold adaptation
Claverie, P.; Vigano, C.; Ruysschaert, J. M. et al

in Biochimica et Biophysica Acta-Proteins and Proteomics (2003), 1649(2), 119-122

The alpha-amylase precursor from the bacterium Pseudoalteromonas haloplanktis possesses a propeptide at the C-terminus possibly responsible for outer membrane translocation. Unlike the predicted beta ... [more ▼]

The alpha-amylase precursor from the bacterium Pseudoalteromonas haloplanktis possesses a propeptide at the C-terminus possibly responsible for outer membrane translocation. Unlike the predicted beta-barrel of autotransporters, this C-terminal propeptide displays a noticeable alpha-helix content. It is connected to the enzyme by a disordered linker and has no significant interaction with the catalytic domain. The microcalorimetric pattern of the precursor also demonstrates that the stability of protein domains may evolve differently. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

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See detailPulmonary surfactant from healthy Belgian white and blue and Holstein Friesian calves: Biochemical and biophysical comparison
Danlois, F.; Zaltash, S.; Johansson, J. et al

in Veterinary Journal (2002), 163

The biochemical composition and biophysical behaviour of pulmonary surfactant samples isolated from healthy Belgian White and Blue (BWB) and Holstein Friesian (HF) calves have been investigated and ... [more ▼]

The biochemical composition and biophysical behaviour of pulmonary surfactant samples isolated from healthy Belgian White and Blue (BWB) and Holstein Friesian (HF) calves have been investigated and compared. Interesting differences in composition have been demonstrated. In particular, a higher level of total hydrophobic surfactant-associated proteins (SP) (due to higher levels of SP-B and SP-C) is reported in HF calves compared to BWB calves. Higher levels of phosphatidylcholine (PC) and especially the disaturated form of PC were also found in HF as compared to BWB calves. No immediate effect on the surface tension properties evaluated by the pulsating bubble surfactometer was found between the surfactant samples of the two breeds under physiological conditions. However, since a high content of disaturated PC and the presence of the SP-B and SP-C are thought to be essential for the surface activity, we propose that the reported modifications could contribute to the apparently lower resistance of the BWB calves to respiratory troubles in comparison with HF calves. (C) 2002 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailThe C-terminal autotransporter of Pseudoalteromonas haloplanktis alpha-amylase forms a pore in lipid bilayer membranes
Claverie, Paule; Homble, F.; Ruysschaert, J.M. et al

Poster (2001)

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See detailVery Low Surfactant Protein C Contents in Newborn Belgian White and Blue Calves with Respiratory Distress Syndrome
Danlois, F.; Zaltash, S.; Johansson, J. et al

in Biochemical Journal (2000), 351(Pt 3), 779-87

We have studied a respiratory distress syndrome (RDS) occurring in newborn calves of the Belgian White and Blue (BWB) breed that represents the large majority of beef cattle in Belgium. Pulmonary ... [more ▼]

We have studied a respiratory distress syndrome (RDS) occurring in newborn calves of the Belgian White and Blue (BWB) breed that represents the large majority of beef cattle in Belgium. Pulmonary surfactant isolated from 14 BWB newborn calves that died from RDS and from 7 healthy controls was analysed for composition and surface activity. An extremely low content or, in some instances, an absence of surfactant protein C (SP-C) was detected in the RDS samples by Western blotting and differential amino acid analysis [0.03+/-0.01% (w/w) relative to total phospholipids, compared with 0.39+/-0.06% for healthy controls (means+/-S.E.M., P < 0.001)]. The contents of surfactant protein B (SP-B) were similar in RDS and control samples. The crude surfactant samples isolated from RDS calves had higher ratios of total protein to total phospholipid, altered phospholipid profiles and lower SP-A contents. Both crude and organic extracts of RDS surfactant samples showed increased dynamic surface tension compared with healthy controls when evaluated with a pulsating-bubble surfactometer. The addition of purified SP-C to organic extracts of RDS surfactant samples lowered surface tension. Strongly decreased levels of mature SP-C associated with fatal RDS and altered surface activity in vitro have, to the best of our knowledge, not been previously reported. The mechanisms underlying RDS and the decrease in SP-C in BWB calves remain to be established. [less ▲]

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See detailFusion Of Bovine Leukemia Virus With Target Cells Monitored By R18 Fluorescence And Pcr Assays
Zarkik, S.; Defrisequertain, F.; Portetelle, Daniel ULg et al

in Journal of Virology (1997), 71(1),

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See detailHelix Helix Interactions In Reconstituted High-Density-Lipoproteins
Lins, Laurence ULg; Brasseur, Robert ULg; De Pauw, Mc. et al

in Biochimica et Biophysica Acta-Lipids and Lipid Metabolism (1995), 1258(1), 10-8

In this work we calculated the ionic interactions between adjacent amphipathic helices of apo A-I and apo A-IV. The calculation of the electrostatic potential around the helices helps identify the charged ... [more ▼]

In this work we calculated the ionic interactions between adjacent amphipathic helices of apo A-I and apo A-IV. The calculation of the electrostatic potential around the helices helps identify the charged residues susceptible to form salt bridges between adjacent helices. An estimation of the stability of the different pairs of helices is derived from the calculation of the energy of interaction between contiguous helices at a water/lipid interface after energy minimization. The most stable energetic conformation corresponds to the 17-residue helices oriented anti-parallel and separated by a stretch of 5 residues in an extended beta-strand conformation, as calculated through the 'stereo alphabet' calculation procedure. In a pair of helices, the hydrophobic faces are directed towards the lipid core of the discoidal phospholipid-apolipoprotein complex and the hydrophobic lipid-protein interactions are major determinants for the stability of the complex. Interactions between polar residues located on the opposite face of the helix and water molecules can also contribute to the overall energy of the system. Finally, salt bridge formation between residues of opposite charge along the edge of the helical segments contribute to the cooperativity of the phospholipid-apolipoprotein complex formation. The mode of assembly of the amphipathic helical repeats of the apolipoproteins around the edge of a discoidal complex is therefore determined both by the hydrophobic character of the residues and by the charge complementarity along the edge of the helices which increases the structural stability and determines the relative orientation of the helices. [less ▲]

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See detailProposition Of A 3-Dimensional Representation Of The Constitutive Protein Of The Hepatitis-B Surface-Antigen Particles
Sonveaux, N.; Ruysschaert, Jm.; Brasseur, Robert ULg

in Journal of Protein Chemistry (1995), 14(6), 477-86

Hepatitis B surface antigen particles are composed of the major viral envelope protein, the S protein, embedded into a lipid shell. The description of the folding of this protein within the particle ... [more ▼]

Hepatitis B surface antigen particles are composed of the major viral envelope protein, the S protein, embedded into a lipid shell. The description of the folding of this protein within the particle membrane could provide helpful information for replacing surface-exposed protein domains by foreign sequences without destabilizing the particle structure. Since the crystallization of the protein in its lipid environment remains inaccessible in the near future, alternative approaches had to be envisaged. We combine here the available experimental structural and topological data with a conformational procedure to identify membrane-associated domains of the HBsAg protein and to propose a three-dimensional description of their assembly within the particle membrane. The proposed protein structure is composed of four membrane-spanning helices and an amphipatic helix located on the inner surface membrane. The transmembrane helices are assembled into a highly hydrophobic complex in which no access to the water environment is allowed. The approach could be extended to other membrane-associated proteins. [less ▲]

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See detailFusogenic Segments Of Bovine Leukemia-Virus And Simian Immunodeficiency Virus Are Interchangeable And Mediate Fusion By Means Of Oblique Insertion In The Lipid Bilayer Of Their Target-Cells
Voneche, V.; Portetelle, Daniel ULg; Kettmann, Richard ULg et al

in Proceedings of the National Academy of Sciences of the United States of America (1992), 89(9),

Modified bovine leukemia virus (BLV) glycoproteins were expressed by using vaccinia virus recombinants, and their fusogenic capacities were examined by a syncytia-formation assay. This analysis indicates ... [more ▼]

Modified bovine leukemia virus (BLV) glycoproteins were expressed by using vaccinia virus recombinants, and their fusogenic capacities were examined by a syncytia-formation assay. This analysis indicates that (i) both BLV envelope glycoproteins gp51 and gp30 are necessary for cell fusion; (ii) insertion of the N-terminal segment of gp30 (fusion peptide) into the lipid bilayer in an oblique orientation, as predicted by computer conformational analysis, results in fusogenic capacities higher than insertion in a perpendicular or parallel orientation; and (iii) replacement of the BLV fusion peptide with its simian immunodeficiency virus counterpart does not modify the fusogenic capacity of the BLV glycoprotein. [less ▲]

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See detailAcido-basic properties of lipophilic substances: A surface potential approach
Caspers, J.; Goormaghtigh, E.; Ferreira, J. et al

in Journal of Colloid & Interface Science (1983), 91(2), 546-551

A general procedure allowing the acido-basic properties of lipophilic compounds to be defined is described. Drugs are spread at the air-water interface and the surface potential is recorded at different ... [more ▼]

A general procedure allowing the acido-basic properties of lipophilic compounds to be defined is described. Drugs are spread at the air-water interface and the surface potential is recorded at different pH values of the aqueous subphase. Comparison of this experimental parameter and the Gouy-Chapman theory prediction allows the calculation of the acid (or basic) dissociation constants and the surface charge density. [less ▲]

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See detailEvaluation of the lipid-drug association constant in model membranes: A monolayer approach
Goormaghtigh, E.; Brasseur, Robert ULg; Vanderbranden, M. et al

in Bioelectrochemistry and Bioenergetics (Lausanne, Switzerland) (1982), 9(4), 489-498

A general procedure of evaluation of the lipid-drug association constant in monolayer is presented. Lipids are spread at the air-water interface and the drugs injected into the aqueous subphase ... [more ▼]

A general procedure of evaluation of the lipid-drug association constant in monolayer is presented. Lipids are spread at the air-water interface and the drugs injected into the aqueous subphase. Association constant potential and predictions from the Gouy-Chapman theory. Several procedures of calculation are described. [less ▲]

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See detailA23187 Ionophore—ca2+ interfacial complex: a monolayer approach
Ferreira, J.; Caspers, J.; Brasseur, Robert ULg et al

in Journal of Colloid & Interface Science (1981), 81(1), 158-168

This paper presents a new approach to study A23187 ionophore in an aqueous environment. The ionophore was spread at the air—water interface. Surface pressure and tritium—hydrogen surface exchange ... [more ▼]

This paper presents a new approach to study A23187 ionophore in an aqueous environment. The ionophore was spread at the air—water interface. Surface pressure and tritium—hydrogen surface exchange measurements demonstrated the conformational stability of A23187 in the free and complexed forms at the interface. Exchange measurements suggested that the A23187 ionophore adopts an interfacial conformation in which hydrogen bonds are not accessible to the aqueous solvent. Surface potential measurements allowed the calculation of the intrinsic dissociation constant of the ionophore carboxylic group in an aqueous environment (pKi = 5). The ionophore activity sequence for bivalent ions was Ca2+>Mg2+⇓Ba2+ This sequence is comparable to those obtained by other authors inorganic solution. Surface radioactivity measurements performed with 45Ca2+ in the subphase demonstrated the formation of a neutral complex between two negatively charged ionophore molecules and one Ca2+ ion. This reaction was only observed at pH higher than 5. The association constant of the interfacial ionophore-Ca2+ complex was calculated. [less ▲]

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See detailProperties of mixed monolayers of lecithin and spin probe. II Analysis of the molecular organization
Chatelain, P.; Brasseur, Robert ULg; Ruysschaert, J. M. et al

in Journal of Colloid & Interface Science (1979), 72(2), 294-303

This paper seeks to investigate the molecular organization of fatty acid spin label (4-palmitamido-2,2,6,6-tetramethylpiperidine-1-oxyl) and dipalmitoylphosphatidylcholine molecules in monolayer vesicles ... [more ▼]

This paper seeks to investigate the molecular organization of fatty acid spin label (4-palmitamido-2,2,6,6-tetramethylpiperidine-1-oxyl) and dipalmitoylphosphatidylcholine molecules in monolayer vesicles. The molar ratio of the spin probe was varied from 1 to 22% and the corresponding electron spin resonance spectra were measured at 25 and 48°C. These spectra were analysed in terms of the dipole-dipole and exchange interactions occuring between the radicals. From a computer simulation, a quantitative analysis of these interactions could be made. Comparison of these data with theoretical models indicate that above the lipid phase transition, i.e., at 48°C, the membrane is homogeneous and the label molecules diffuse randomly in the lecithin bulk phase (D = 3.8 X 10-8 cm2/sec). At 25°C, the membrane model can be viewed as a mosaic structure composed of spin probe clusters (7.9 X 1011 clusters/cm2). The size of the clusters as well as the minimal mean distance between two cluster edges could be calculated as a function of the spin label molar ratio. These results are used to interpret the observations made in the first paper of this series [Chatelain et ak., J. Colloid Interface Sci. 72, 287 (1979)] concerning the surface viscosity of the mixed monolayer and the kinetics of the enzymatic activity of phospholipase A2. It can be concluded that above a critical spin label concentration (10-15%) the properties of the entire lecithin phase are influenced by the presence of the spin probe clusters. [less ▲]

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