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See detailInteractions of cryptolepine and neocryptolepine with unusual DNA structures
Guittat, Lionel; Alberti, Patrizia; Rosu, Frédéric ULg et al

in Biochimie (2003), 85(5), 535-547

Cryptolepine, the main alkaloid present in the roots of Cryptolepis sanguinolenta, presents a large spectrum of biological properties. It has been reported to behave like a DNA intercalator with a ... [more ▼]

Cryptolepine, the main alkaloid present in the roots of Cryptolepis sanguinolenta, presents a large spectrum of biological properties. It has been reported to behave like a DNA intercalator with a preference for GC-rich sequences. In this study, dialysis competition assay and mass spectrometry experiments were used to determine the affinity of cryptolepine and neocryptolepine for DNA structures among duplexes, triplexes, quadruplexes and single strands. Our data confirm that cryptolepine and neocryptolepine prefer GC over AT-rich duplex sequences, but also recognize triplex and quadruplex structures. These compounds are weak telomerase inhibitors and exhibit a significant preference for triplexes over quadruplexes or duplexes. (C) 2003 Editions scientifiques et medicales Elsevier SAS and Societe francaise de biochimie et biologic moleculaire. All rights reserved. [less ▲]

Detailed reference viewed: 85 (5 ULg)
See detailInteractions of human breast adenocarcinoma with the extracellular matrix - a new concept to study cancer invasion.
Foidart, Jean-Michel ULg; Verly, M.; Castronovo, Vincenzo ULg et al

in Evaluation du Risque de Cancer Mammaire. Chimiothérapie Première ? (1985)

Detailed reference viewed: 7 (0 ULg)
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See detailInteractions of invasive cells with native and modified extracellular matrix in vitro.
Bracke, M.; Castronovo, Vincenzo ULg; De Bruyne, G. et al

in Advances in Experimental Medicine and Biology (1988), 233

Detailed reference viewed: 12 (3 ULg)
See detailInteractions of invasive cells with native and modified extracellular matrix in vitro.
Bracke, M.; Castronovo, Vincenzo ULg; De Bruyne, G. et al

in In Prodi, G.; Liotta, L. A.; Lollini, P. L. (Eds.) et al Cancer Metastasis : Biological and Biochemical Mechanisms and Clinical Aspects. (1988)

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See detailInteractions of iturinic antibiotics with plasma membrane. Contribution of biomimetic membranes.
Nasir, Mehmet Nail ULg; Besson, Françoise; Deleu, Magali ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(3), 505-516

Iturinic antibiotics are produced by Bacillus subtilis strains and constitute a family including iturin A, mycosubtilin and bacillomycins D, F and Lc. They are cyclic lipopeptides having -amino fatty ... [more ▼]

Iturinic antibiotics are produced by Bacillus subtilis strains and constitute a family including iturin A, mycosubtilin and bacillomycins D, F and Lc. They are cyclic lipopeptides having -amino fatty acids linked up to a peptide constituted by seven -aminoacids with an invariable LDDLLDL chiral sequence. The first three -aminoacids containing the tyrosyl residue are the same for all members. They are well-known by their strong antifungal activities but they have also antibacterial and hemolytic properties. These biological properties are due to their amphiphilic nature allowing interactions with different membrane components. Sterols found in plasma membranes are the privileged interaction partners of these lipopeptides. Moreover, the tyrosyl residue of the iturinic antibiotics seems to play an important role during their fixation to the plasma membrane, the result of which is often the cellular lysis. Within plasma membranes, there are particular regions with high sterol content. These microdomains have a different composition compared to the rest of the membrane; they are enriched in certain lipids and proteins and they are involved in many key cellular processes. Their perturbation could then have an important impact on the cell. Due to their composition, these microdomains could constitute the preferential target of iturin antibiotics. This review aims to synthetize the works related to the biological activities of iturinic antibiotics and focusses especially to their understanding at the molecular level with a discussion on the key chemical groups of the iturin antibiotics and on the potentiality of microdomains to constitute a target for these molecules [less ▲]

Detailed reference viewed: 43 (12 ULg)
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See detailInteractions of lipases with milk fat globule membrane monolayers using a Langmuir film balance
Danthine, Sabine ULg; Blecker, Christophe ULg

in International Dairy Journal (2014), 35(1), 81-87

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See detailInteractions Of Macrolide Antibiotics (Erythromycin A, Roxithromycin, Erythromycylamine [Dirithromycin], And Azithromycin) With Phospholipids: Computer-Aided Conformational Analysis And Studies On Acellular And Cell Culture Models
Montenez, Jp.; Van Bambeke, F.; Piret, J. et al

in Toxicology and Applied Pharmacology (1999), 156(2), 129-40

The potential of 14/15 membered macrolides to cause phospholipidosis has been prospectively assessed, and structure-effects examined, using combined experimental and conformational approaches. Biochemical ... [more ▼]

The potential of 14/15 membered macrolides to cause phospholipidosis has been prospectively assessed, and structure-effects examined, using combined experimental and conformational approaches. Biochemical studies demonstrated drug binding to phosphatidylinositol-containing liposomes and inhibition of the activity of lysosomal phospholipase A1 toward phosphatidylcholine included in the bilayer, in close correlation with the number of cationic groups carried by the drugs (erythromycin A </= roxithromycin < erythromycylamine </= azithromycin). In cultured cells (fibroblasts), phospholipidosis (affecting all major phospholipids except sphingomyelin) was observed after 3 days with the following ranking: erythromycin A </= roxithromycin < erythromycylamine < azithromycin (roxithromycin could, however, not be studied in detail due to intrinsic toxicity). The difference between erythromycylamine and azithromycin was accounted for by the lower cellular accumulation of erythromycylamine. In parallel, based on a methodology developed and validated to study drug-membrane interactions, the conformational analyses revealed that erythromycin A, roxithromycin, erythromycylamine, and azithromycin penetrate into the hydrophobic domain of a phosphatidylinositol monolayer through their desosamine and cladinose moieties, whereas their macrocycle is found close to the interface. This position allows the aminogroups carried by the macrocycle of the diaminated macrolides (erythromycylamine and azithromycin) to come into close contact with the negatively charged phosphogroup of phosphatidylinositol, whereas the amine located on the C-3 of the desosamine, common to all four drugs, is located at a greater distance from this phosphogroup. Our study suggests that all macrolides have the potential to cause phospholipidosis but that this effect is modulated by toxicodynamic and toxicokinetic parameters related to the drug structure and mainly to their cationic character. [less ▲]

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See detailInteractions of subunits Asa2, Asa4 and Asa7 in the peripheral stalk of the mitochondrial ATP synthase of the chlorophycean alga Polytomella sp.
Miranda-Astudillo, Hector; Cano-Estrada, Araceli; Vazquez-Acevedo, Miriam et al

in Biochimica et Biophysica Acta-Bioenergetics (2014), 1837

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See detailInteractions of the antifungal mycosubtilin with ergosterol-containing interfacial monolayers
Nasir, Mehmet Nail ULg; Besson, Françoise

in Biochimica et Biophysica Acta - Biomembranes (2012), 1818(5), 1302-1318

Mycosubtilin, an antimicrobial lipopeptide produced by Bacillus subtilis, is characterized by strong antifungal activities. The molecular mechanisms of its biological activities on the membranes of the ... [more ▼]

Mycosubtilin, an antimicrobial lipopeptide produced by Bacillus subtilis, is characterized by strong antifungal activities. The molecular mechanisms of its biological activities on the membranes of the sensitive yeasts or fungi have not yet been clearly elucidated. Our purpose was to mimic the mycosubtilin interactions with these membranes using various Langmuir monolayers. Since the major sterol of yeasts or fungi is ergosterol, the interactions of mycosubtilin with monolayers constituted by ergosterol, DPPC/ergosterol or DPPC/sphingomyelin/ergosterol were examined at different initial surface pressures (Πi). Plotting the mycosubtilin-induced surface pressure increases versus Πi allowed to determine that the exclusion pressures of mycosubtilin from these different monolayers is higher than the surface prevailing within the biological membranes. However, this behavior was lost when mycosubtilin was interacting with ergosteryl acetate-containing monolayers. This suggests the involvement of the sterol alcohol group in the mycosubtilin interactions within membranes. Furthermore, the behavior of mycosubtilin with stigmasterol, similar to that observed with ergosterol, differs from that previously observed with cholesterol, suggesting a role of the alkyl side chain of the sterols. The adsorption of mycosubtilin to ergosterol monolayers induced changes in the lipopeptide orientation at the air-water interface as revealed by polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS). Moreover, imaging the air-water interface by Brewster angle microscopy (BAM) indicates that mycosubtilin induced changes in the organization and morphology of monolayers containing pure ergosterol with the appearance of small condensed dots, suggesting again that the target of mycosubtilin might be the ergosterol present in the membranes of the sensitive yeasts or fungi. [less ▲]

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See detailInteractions of the natural antimicrobial mycosubtilin with phospholipid membrane models
Nasir, Mehmet Nail ULg; Thawani, Ankita; Kouzayha, Achraf et al

in Colloids and Surfaces B: Biointerfaces (2010), 78

Among the secondary metabolite lipopeptides produced by Bacillus subtilis, mycosubtilin is characterized by its strong antifungal activities. Even though its structure and its cellular target, the ... [more ▼]

Among the secondary metabolite lipopeptides produced by Bacillus subtilis, mycosubtilin is characterized by its strong antifungal activities. Even though its structure and its cellular target, the cytoplasmic membrane, have been determined, the molecular mechanisms of the biological activity of mycosubtilin have not been completely elucidated. In this work, the interactions between mycosubtilin and cytoplasmic membranes were modelled by using biomimetic systems such as Langmuir monolayers at the air-water interface and lipid multilamellar vesicles. The interactions of mycosubtilin with these biomimetic systems were examined, for the first time, by using specific techniques such as polarization modulation infrared reflection absorption spectroscopy, Brewster angle microscopy and high-resolution magic angle spinning NMR. Our findings indicate that mycosubtilin alone, at the air-water interface, forms a monolayer film and keeps its turn conformation. In the presence of DMPC, mycosubtilin binds to phospholipid monolayers, in a surface pressure-dependent manner. This binding results in the appearance of condensed domains which can be due to the formation of mycosubtilin clusters and/or to the lipopeptide aggregation with some phospholipid molecules and/or the formation of liquid-condensed domains of DMPC. Furthermore, in multilamellar vesicles, the mycosubtilin-DMPC interactions take place at the level of the aliphatic chains of the phospholipid because the phase transition temperature of DMPC decreased in the presence of mycosubtilin. [less ▲]

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See detailInteractions of two aphid species on the african eggplant, sorrel and amaranth
Bayendi-Loudit, Sandrine ULg; Chevalier Mendes Lopes, Thomas ULg; Francis, Frédéric ULg

Poster (2013, September)

Aphids (Homoptera: Aphididae) are polyphagous insects which can be found on several crops in temperate zones, as well as in the tropics. The multiplication of Aphis gossypii Glover (C9 cucumber, Burk ... [more ▼]

Aphids (Homoptera: Aphididae) are polyphagous insects which can be found on several crops in temperate zones, as well as in the tropics. The multiplication of Aphis gossypii Glover (C9 cucumber, Burk cotton and Pipo pepper strains) and Myzus persicae Sulzer was studied in the laboratory on three plant species: African eggplant, Solanum aethiopicum, sorrel, Hibiscus sabdariffa, and amaranth, Amaranthus spp. Periodic counts were carried out to monitor population growth. The multiplication rate of M. persicae wass higher than that of A. gossypii when these two species were present together on eggplant. Amaranth was less suitable for the development of both species, but Myzus persicae again had a better multiplication rate than Aphis gossypii. This study illustrated the importance of considering not only one pest species, but the whole herbivore guild, especially when biological control is important. [less ▲]

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See detailInteractions Traditions Orales et Blues dans SULA, un roman de Toni Morrison
Sacré, Robert ULg

in Actes-Handelingen-Akten Congrès de Liège , III (1995, August)

Detailed reference viewed: 7 (1 ULg)
See detail"Interactions verbales et pratique pédagogique en classes de langues"
Defays, Jean-Marc ULg

Scientific conference (2011, February 14)

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See detailInteractions verbales parents-enfants : Etude longitudinale d'un cas
Lafontaine, Dominique ULg

in Enfance (1982), 1-2

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See detailInteractions with musical long-term memory are a critical component of musical working memory
Gorin, Simon ULg; Majerus, Steve ULg

Poster (2013, August 10)

The nature and mechanisms of working memory (WM) for musical information remain poorly understood. The aim of this study is to show that musical WM strongly depends upon long-term memory (LTM) mechanisms ... [more ▼]

The nature and mechanisms of working memory (WM) for musical information remain poorly understood. The aim of this study is to show that musical WM strongly depends upon long-term memory (LTM) mechanisms and requires access to the long-term musical knowledge base. Two groups of participants (musicians and non-musicians) participated first in an implicit learning task during which they heard for about 30 minutes a continuous sequence of tones governed by a new musical grammar. Then, they performed an immediate serial recall task of musical sequences of increasing length; half of the sequences were constructed in accordance to the rules of the new grammar presented during the implicit learning task. Participants have to reproduce the sequences by humming and their performances were calculated on the basis of the deviation between their production and the stimulus needed to be reproduced. The results showed a significant advantage for the lists governed by the grammar previously learned. Overall, this study shows that performance on a musical WM task is enhanced by musical knowledge stored in LTM. This study is the first to demonstrate the dependency of musical WM on musical LTM knowledge, implying that existing models of musical WM need to be extended to account for this WM-LTM interaction. [less ▲]

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See detailAn interactive activation model of face naming
Brédart, Serge ULg; Valentine, T.; Calder, A. et al

in Quarterly Journal of Experimental Psychology (1995), 48A(2), 466-486

Burton and Bruce's (1992) model of face naming predicts a "fan effect", in which naming of famous people about whom many descriptive properties are known should be slower than naming of celebrities about ... [more ▼]

Burton and Bruce's (1992) model of face naming predicts a "fan effect", in which naming of famous people about whom many descriptive properties are known should be slower than naming of celebrities about whom few properties are known. An experiment is reported that showed that, contrary to this prediction, knowledge of many descriptive properties facilitated face-naming latency. An alternative architecture for an interactive activation model is proposed in which descriptive properties are represented in separate pools of units for each domain of information and in which names are represented by a separate pool of lexical output units. Computer simulations showed that this model could simulate the previously available empirical data as effectively as Burton and Bruce's (1992) original model. However, the proposed model could also simulate the effect of the number of known descriptive properties upon face-naming latency observed in the experiment reported. The new architecture also has the advantage of being more compatible with current models of speech production, and it allows preserved access to unique semantic properties in the context of impaired face naming as reported in the neuropsychological literature. [less ▲]

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See detailAn interactive and real-time 3D auralization system for room acoustics (the AURALIAS project)
Bos, Lionel ULg; Embrechts, Jean-Jacques ULg

in Proceedings of the 3D Stereo Media congress, Liege 2010 (2009, December)

Detailed reference viewed: 109 (9 ULg)