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See detailCell turnover in BLV-infected sheep.
Debacq, C.; Peremans, T.; Kerkhofs, P. et al

in AIDS Research and Human Retroviruses (2001), 17(1), 13

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See detailA Cell Type-Specific and Gap Junction-Independent Mechanism for the Herpes Simplex Virus-1 Thymidine Kinase Gene/Ganciclovir-Mediated Bystander Effect
Princen, Frederic; Robe, Pierre ULg; Lechanteur, Chantal ULg et al

in Clinical Cancer Research : An Official Journal of the American Association for Cancer Research (1999), 5(11), 3639-44

Tumor cells expressing the herpes simplex virus type 1 thymidine kinase (HSV-tk) gene are killed by nucleoside analogues such as ganciclovir (GCV). GCV affects not only the cells expressing HSV-tk but ... [more ▼]

Tumor cells expressing the herpes simplex virus type 1 thymidine kinase (HSV-tk) gene are killed by nucleoside analogues such as ganciclovir (GCV). GCV affects not only the cells expressing HSV-tk but also neighboring cells that do not express the gene; this phenomenon commonly is called "bystander effect." GCV metabolites transfer via gap junctional intercellular communication (GJIC) accounts for the bystander effect in different cell lines, but other mechanisms have also been described. In this study, we analyzed the mechanisms of the bystander effect in two cell lines exhibiting different capacities of communication (DHD/K12 and 9L). The 9L cells exhibited a very good bystander effect, which was completely blocked by a long-term inhibitor of GJIC, 18 alpha-glycyrrhetinic acid. DHD/K12 cells exhibited a moderate bystander effect that was not abolished by 18 alpha-glycyrrhetinic acid or 1-octanol, another strong inhibitor of GJIC. Interestingly, we also observed a bystander effect in cultures where HSV-tk-expressing DHD/K12 cells were physically separated from their untransfected counterparts but grown in the same medium. Moreover, the transfer of filtered conditioned medium from GCV-treated HSV-tk-expressing DHD/K12 cells to DHD/K12 parental cells induced a decrease of survival in a concentration-dependent manner, suggesting that the bystander effect in this cell line was mediated by a soluble factor. [less ▲]

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See detailCell Type-Specific Role for Reactive Oxygen Species in Nuclear Factor-Kappab Activation by Interleukin-1
Bonizzi, G.; Piette, Jacques ULg; Merville, Marie-Paule ULg et al

in Biochemical Pharmacology (2000), 59(1), 7-11

The role of reactive oxygen intermediates (ROIs) in nuclear factor-kappaB (NF-kappaB) activation remains a matter of controversy. We have studied whether ROIs played any role in NF-kappaB induction by ... [more ▼]

The role of reactive oxygen intermediates (ROIs) in nuclear factor-kappaB (NF-kappaB) activation remains a matter of controversy. We have studied whether ROIs played any role in NF-kappaB induction by interleukin-1beta (IL-1beta) in different cell types. Our studies indicated three different pathways. IL-1beta stimulation of lymphoid cells generates ROIs, which are required for IkappaB-alpha degradation and NF-kappaB activation. The source of these ROIs is the 5-lipoxygenase (5-LOX) enzyme. In monocytic cells, ROIs are also produced in response to IL-1beta and necessary for NF-kappaB induction, but their source appears to be the NADPH oxidase complex. Finally, epithelial cells do not generate ROIs after IL-1beta stimulation, but do rapidly activate NF-kappaB. Interestingly, transfection of epithelial cells with the 5-LOX and 5-LOX activating protein expression vectors restored ROI production and ROI-dependent NF-kappaB activation in response to IL-1beta. Our data thus indicate that ROIs are cell type-specific second messengers for NF-kappaB induction by IL-1beta. [less ▲]

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See detailThe Cell Wall Peptidoglycan of Bacillus megaterium KM. I. Studies on the Stereochemistry of α,α'-Diaminopimelic Acid
Bricas, E.; Ghuysen, Jean-Marie ULg; Dezelee, P.

in Biochemistry (1967), 6(8), 2598-2607

α,α'-Diaminopimelic acid (DAP) occurs in the wall peptidoglycan of Bacillus megaterium KM predominantly in the form of its meso isomer (about 85% of the total residues) and, in minor amounts, in the form ... [more ▼]

α,α'-Diaminopimelic acid (DAP) occurs in the wall peptidoglycan of Bacillus megaterium KM predominantly in the form of its meso isomer (about 85% of the total residues) and, in minor amounts, in the form of its DD isomer. The amino groups on the L carbon of the meso-DAP residues are involved in peptide linkages to the glutamic acid residues. Most of the amino groups on the D carbon of the meso-DAP residues are free; some of them are substituted, thus probably serving to cross-link peptide subunits. These amino groups can be liberated by a Streptomyces endopeptidase. None of the DD-DAP residues have amino groups free. Moreover, these groups are not liberated by endopeptidase treatment. The peptidoglycan upon enzymatic degradation yields mainly two fractions. A major fraction is composed of disaccharide peptide monomer subunits containing only the meso isomer of DAP. A second minor fraction is composed of disaccharide peptide oligomers containing both meso and DD isomers of DAP. The meso-DAP residues isolated as monodinitrophenyl derivatives from both fractions have optical rotations and optical rotatory dispersions identical with that of synthetic monodinitrophenyl-meso-DAP obtained by dinitrophenylation of the amino group on the D carbon. The assignment of the DD configuration to the DAP residues which are not meso rests upon the optical rotatory properties of their bisdinitrophenyl derivatives. [less ▲]

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See detailCell wall phenylpropanoid-related gene expression in early maize recombinant inbred lines differing in parental alleles at a major lignin QTL position
Thomas, Justine; Guillaumie, Sabine; Verdu, Cindy ULg et al

in Molecular Breeding (2010), 25

Fifteen quantitative trait loci (QTL) for cell wall digestibility and lignin content were shown in the recombinant inbred line (RIL) progeny descended from the cross between F288 and F271, two early dent ... [more ▼]

Fifteen quantitative trait loci (QTL) for cell wall digestibility and lignin content were shown in the recombinant inbred line (RIL) progeny descended from the cross between F288 and F271, two early dent lines of contrasted cell wall digestibility. Among these QTL, those located in bin 6.06, respectively explained 20 and 40% of the phenotypic variation for lignin content and cell wall digestibility. Expression of genes related to cell wall and lignin biosynthesis was investigated with the ‘‘MaizeWall’’ macro-array in two RIL having favorable alleles for low lignin content and high cell wall digestibility, except in bin 6.06 where RIL39 and RIL99 had unfavorable and favorable alleles, respectively. In the lignin pathway, three PAL, 4CL1, ZmCCR1, COMT, and ZmCAD2 genes were under-expressed in RIL99 in comparison to RIL39. In addition, two cytochrome P450, ZmCHS, and ZmCHI1 genes were simultaneously under-expressed while F5H2 and two OMT ZRP4-like genes were over-expressed. However, none of these genes were mapped in bin 6.06. Based on maize–rice synteny and on Maize Genome Sequencing Project data, several putative candidate genes related to lignin content and lignified tissue patterning were found in the support interval of bin 6.06 QTL. These genes included one C30H which is likely the missing constitutive gene of the maize lignin pathway. Three ZRP4-like OMT were also shown in the support interval of the QTL. However, their involvement in the lignin pathway has not yet been firmly established. Several regulation or transcription factors were also shown in the QTL support interval. Among them, MYB, zinc finger, bZIP, and COV1 genes belong to families with members involved in lignification regulation or in lignified tissue patterning. In addition, auxin response factors have been shown to be indirectly involved in plant lignification. Moreover, several genes encoding proteins of unknown function and genes annotated ‘‘retrotransposon-like’’ were also located in the QTL support interval. Current results are not conclusive on the candidate gene discovery, but strengthen the hypothesis that regulation genes are better candidates than genes involved in the monolignol pathway. Fine mapping, association genetics, and/or functional validation have to be considered for more definite conclusions. [less ▲]

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See detailCell wall polysaccharides hydrolysis of malting barley (Hordeum vulgare L.) : a review
Jamar, Catherine ULg; du Jardin, Patrick ULg; Fauconnier, Marie-Laure ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2011), 15(2), 301-313

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See detailCell walls of Streptococcus pyogenes, type 14. C polysaccharide-peptidoglycan and G polysaccharide-peptidoglycan complexes
Munoz, E.; Ghuysen, Jean-Marie ULg; Heymann, H.

in Biochemistry (1967), 6(12), 3659-2670

About 20% of the organic phosphorus present in cell walls of Streptococcus pyogenes occurs as N-acetylmuramic acid 6-phosphate residues (50 mµequiv/mg of walls). These groups link about 10% of the ... [more ▼]

About 20% of the organic phosphorus present in cell walls of Streptococcus pyogenes occurs as N-acetylmuramic acid 6-phosphate residues (50 mµequiv/mg of walls). These groups link about 10% of the peptidoglycan subunits to a hitherto unrecognized polysaccharide. This polymer was isolated after degradation of trypsin-treated walls with Streptornyces F1 endo-N-acetylmuramidase; it consists of disaccharide peptide monomer (50 mµmoles/mg of walls) linked through a phosphodiester bridge to a polymer containing, per peptide monomer, five to six D-glucose residues, one glucosamine residue, and four to five unidentified hexosamine compounds. This polymer is designated as G polysaccharide. About 70% of the organically bound phosphorus in the cell walls (150 mµequiv/mg of walls) is present in the form of phosphodiester groups in the interior of the rhamnose-containing C polysaccharide. The linkages of the C-polysaccharide chains to the peptidoglycan are visualized as bridges of trirhamnose groupings, each bearing one β-linked N-acetylgluco-samine residue, bound at the reducing end, either directly or through an as yet undetermined intervening molecule, to C-4 of an N-acetylmuramic acid residue. After degradation of walls by endo-N-acetylmurami-dase, the C-polysaccharide chains remain bound to one N-acetylmuramic acid residue. This N-acetylmur-amic acid residue is substituted by one tetrapeptide monomer which in turn is linked via a di-L-alanyl bridge to another disaccharide peptide monomer. A structure for the cell walls of Streptococcus pyogenes is proposed that takes into account all of the recognized covalent linkages among the constituent polymers. [less ▲]

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See detailCell-based description of ventricular contraction in a model of the human cardiovascular system
Kosta, Sarah ULg; Negroni, Jorge; Lascano, Elena et al

in IFAC-PapersOnLine (2015, September)

A multiscale model of the cardiovascular system (CVS) is presented. Hemodynamics is described by a lumped parameter model, while heart contraction is described at the cellular scale. An ... [more ▼]

A multiscale model of the cardiovascular system (CVS) is presented. Hemodynamics is described by a lumped parameter model, while heart contraction is described at the cellular scale. An electrophysiological model and a mechanical model were coupled and adjusted so that the pressure and volume of both ventricles are linked to the force and length of a half-sarcomere. Particular attention was paid to the extremal values of the sarcomere length, which must keep physiological values. This model is able to reproduce healthy behavior, preload variations experiments, and ventricular failure. [less ▲]

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See detailCell-based description of ventricular contraction in a model of the human cardiovascular system
Kosta, Sarah ULg; Negroni, Jorge; Lascano, Elena et al

Poster (2015, August 31)

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See detailCell-Cell and Cell-Matrix Interactions During Breast Cancer Progression
Noël, Agnès ULg; Kebers, F.; Maquoi, Erik ULg et al

in Current Topics in Pathology. Ergebnisse der Pathologie (1999)

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See detailCell-free synthesis of acetylcholine receptor polypeptides
Mendez, B.; Valenzuela, P.; Martial, Joseph ULg et al

in Science (1980), 209(4457), 695-7

Messenger RNA coding for acetylcholine receptor peptides has been identified. This polyadenylate [poly(A)+]RNA from Torpedo californica directs, in a cell-free system, the synthesis of peptides 60,000, 51 ... [more ▼]

Messenger RNA coding for acetylcholine receptor peptides has been identified. This polyadenylate [poly(A)+]RNA from Torpedo californica directs, in a cell-free system, the synthesis of peptides 60,000, 51,000, 49,000 41,000, and 35,000 daltons which account for approximately 2 percent of the total synthesized proteins. The results suggest that several different messenger RNA's code for the receptor subunits. These proteins react specifically to antiserum to native acteylcholine receptor, suggesting that the primary translational product has conformational features similar to the native receptor. Further, the results support the idea that there is post-translational modification of receptor subunits as the molecular weights of the cell-free synthesized proteins differ from those of purified receptor subunits. [less ▲]

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See detailCell-line specific radiosensitizing effect of zalcitabine (DDC)
Coucke, Philippe ULg; Li, Ye-Xiong; Copaceanu, Marie-Laure et al

in Acta Oncologica (1997)

The potential of zalcitabine (ddC) to act as an ionizing radiation response modifier was tested on exponentially growing human cancer cells in vitro. Two human cell lines, WiDr (colon) and MCF-7 (breast ... [more ▼]

The potential of zalcitabine (ddC) to act as an ionizing radiation response modifier was tested on exponentially growing human cancer cells in vitro. Two human cell lines, WiDr (colon) and MCF-7 (breast) were exposed to ddC at 10 p M concentration for various lengths of tide (18, 24, 48 and 72 h). On the WiDr cell line the dual effect of concentration and duration of exposure prior to irradiation was investigated. Experimental endpoints were clonogenicity and viability, as measured by colony formation assay (CFA) and MTT assay respectively. The impact on cell-cycle distribution prior to irradiation was assessed by flow cytometry using a double labeling technique (propidium iodide and bromodeoxyuridine pulse label). A significant reduction in surviving fraction and viability was observed for WiDr-cells irradiated after pre-exposure to 10 pM for 18, 48 and 72 h as compared to corresponding irradiated controls. At lower concentrations (1 and 5 pM), the radiosensitizing effect was only significant after a 72-h exposure (assessed by CFA). For MCF-7, ddC induced a significant modification of the dose response only with 24 and 48 h preincubation. However, the overall effect was less pronounced as compared to WiDr. Cell-cycle analysis showed accumulation in S-phase, 48 and 72 h after treatment with 10 pM ddC in the WiDr cells, with a progressive shift to late S-phase as shown by the biparametric analysis. The degree of radiosensitization is cell-line dependent with the most important sensitization observed on the most <<radioresistant cell line>>, ix., the cell line with the lowest alpha value and highest SF 2 (WiDr). For WiDr, radiosensitization by ddC depends on the duration of exposure and the concentration of the drug. Received 29 February 1996 Accepted 10 December 1996 [less ▲]

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See detailCell-Mediated Immune Response in Calves to Single-Dose, Trickle, and Challenge Infections with Fasciola Hepatica
Bossaert, K.; Jacquinet, E.; Saunders, J. et al

in Veterinary Parasitology (2000), 88(1-2), 17-34

A peripheral blood mononuclear cell (PBMC) proliferation assay was used to study the cell-mediated immune response in eight calves experimentally infected with Fasciola hepatica. Hypersensitivity-related ... [more ▼]

A peripheral blood mononuclear cell (PBMC) proliferation assay was used to study the cell-mediated immune response in eight calves experimentally infected with Fasciola hepatica. Hypersensitivity-related eosinophil and mast-cell responses were also assessed. The primary infection of 500 metacercariae was administered either as a single-dose or as a trickle infection over a 4-week period. Calves were challenge-infected 4 months later with 100 metacercariae and slaughtered 24 weeks postprimary infection. Skin eosinophil counts (SEC) were determined prior to infection on the basis of the intradermal reaction (IDR) to phytohaemagglutinin (PHA). These counts correlated negatively with the mean fluke length but not with the fluke burden found at necropsy. At the end of the experiment, non-specific (PHA) and specific (excretory-secretory parasite, products, FhESAg, and whole-worm extract, FhSomAg) immediate type hypersensitivity IDR were elicited in contrast to delayed type hypersensitivity (DTH) responses. The SEC correlated with blood eosinophilia but not with parasite parameters. These findings suggest that the eosinophil response does not correlate clearly with the development of resistance to F. hepatica infection in cattle. A specific mononuclear cell response to FhSomAg was detectable as early as 7 days after infection in both infected groups, being significantly higher during the very early migratory phase of the juveniles in the single-dose infected calves than in the trickle infected calves. This response remained significantly higher in infected groups than in the control group throughout the experiment. Challenge elicited a significant proliferative response, less pronounced than after primary infection. No production of gamma-interferon (INF-gamma) was recorded 3 weeks after challenge. At necropsy, the mean number of flukes recovered was similar in both infected groups, suggesting that the rate at which the infection is administrated has no effect on protective immunity. Hepatic lesions, similar in both infected groups, were characterised by marked eosinophil and mast-cell infiltration. Liver biopsies were performed and their diagnostic value is discussed. All results suggest that F. hepatica infection predominantly induces a Type-2 response in cattle, and that this response has little protective effect. [less ▲]

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See detailCell-specific interaction of retinoic acid receptors with target genes in mouse embryonic fibroblasts and embryonic stem cells.
Delacroix, Laurence ULg; Moutier, Emmanuel; Altobelli, Gioia et al

in Molecular & Cellular Biology (2010), 30(1), 231-44

All-trans retinoic acid (RA) induces transforming growth factor beta (TGF-beta)-dependent autocrine growth of mouse embryonic fibroblasts (MEFs). We have used chromatin immunoprecipitation to map 354 RA ... [more ▼]

All-trans retinoic acid (RA) induces transforming growth factor beta (TGF-beta)-dependent autocrine growth of mouse embryonic fibroblasts (MEFs). We have used chromatin immunoprecipitation to map 354 RA receptor (RAR) binding loci in MEFs, most of which were similarly occupied by the RAR alpha and RAR gamma receptors. Only a subset of the genes associated with these loci are regulated by RA, among which are several critical components of the TGF-beta pathway. We also show RAR binding to a novel series of target genes involved in cell cycle regulation, transformation, and metastasis, suggesting new pathways by which RA may regulate proliferation and cancer. Few of the RAR binding loci contained consensus direct-repeat (DR)-type elements. The majority comprised either degenerate DRs or no identifiable DRs but anomalously spaced half sites. Furthermore, we identify 462 RAR target loci in embryonic stem (ES) cells and show that their occupancy is cell type specific. Our results also show that differences in the chromatin landscape regulate the accessibility of a subset of more than 700 identified loci to RARs, thus modulating the repertoire of target genes that can be regulated and the biological effects of RA. [less ▲]

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See detailCell-surface MMP-9 regulates the invasive capacity of leukemia blast cells with monocytic features.
Paupert, Jenny ULg; Mansat-De Mas, Veronique; Demur, Cecile et al

in Cell cycle (Georgetown, Tex.) (2008), 7(8), 1047-53

The metalloprotease 9 (MMP-9), a known mediator of tumour invasion, is secreted as a 92 kDa pro-form but a non-secreted variant of 85 Kda has been described. The importance of this variant pro-form in ... [more ▼]

The metalloprotease 9 (MMP-9), a known mediator of tumour invasion, is secreted as a 92 kDa pro-form but a non-secreted variant of 85 Kda has been described. The importance of this variant pro-form in tumor progression remains poorly defined. We previously showed that the DNA repair protein Ku interacts at the cell surface of leukaemia cell lines with the 85 Kda pro-form of MMP-9 and these Ku/MMP-9 complexes regulates cell invasion, highlighting their importance in haematological malignancies. We demonstrate here that all samples of acute myeloid leukaemia (AML) blasts purified from bone marrow of 16 affected patients express the 85 Kda form of MMP-9. However, only AML that display monocytic lineage markers (AML4/5) express this form at the cell surface with co-expression of the membrane associated form of Ku. Blocking antibodies directed against Ku or MMP-9 specifically inhibited cell invasion of those expressing Ku/MMP-9 on the cell surface. The membrane form of Ku might represent an important factor in the exposition to the cell surface of this specific MMP-9 pro-form in AML with monocytic features. These results might have important functional significance in the occurrence of extra-medullar infiltrates of leukaemia cells that occurs frequently during the onset of monocyte-related AML sub-types. [less ▲]

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See detailThe Cellobiose Sensor CebR is the Gatekeeper of Streptomyces scabies Pathogenicity
Francis, Isolde; Jourdan, Samuel ULg; Fanara, Steven ULg et al

in MBio (2015)

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See detailThe cellobiose-sensor CebR is the gatekeeper of Streptomyces scabies pathogenicity
Jourdan, Samuel ULg; Francis, Isolde; Loria, Rosemary et al

Poster (2014, October)

Detailed reference viewed: 94 (11 ULg)