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See detailInduction of a Streptomyces Cacaoi Beta-Lactamase Gene Cloned in S. Lividans
Lenzini, V. M.; Magdalena, J.; Fraipont, Claudine ULg et al

in Molecular & General Genetics [=MGG] (1992), 235(1), 41-8

The previously cloned class A beta-lactamase gene (bla) of Streptomyces cacaoi was shown to be inducible by beta-lactam compounds in the host organism S. lividans. A regulatory region of 2.75 kb was ... [more ▼]

The previously cloned class A beta-lactamase gene (bla) of Streptomyces cacaoi was shown to be inducible by beta-lactam compounds in the host organism S. lividans. A regulatory region of 2.75 kb was identified and the nucleotide sequence determined. It contained four open reading frames (ORFs) of which only two were complete and required for induction. ORF1-ORF2 exerted a positive regulatory effect on the expression of bla. Inactivation of ORF1 or of ORF2 resulted not only in the loss of induction, but also in a 30- to 60-fold decrease in the basal (non-induced) level of beta-lactamase production. ORF1 codes for a DNA-binding protein related to the AmpR repressor/activator, which controls the expression of ampC (class C beta-lactamase) genes in several Enterobacteria. [less ▲]

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See detailInduction of antibody response against hepatitis E virus (HEV) with recombinant human papillomavirus pseudoviruses expressing truncated HEV capsid proteins in mice.
Renoux, Virginie ULg; Fleury, Maxime J J; Bousarghin, Latifa et al

in Vaccine (2008), 26(51), 6602-7

A hepatitis E virus (HEV) vaccine would be valuable to reduce the morbidity and mortality associated with the infection in endemic areas. HEV pseudocapsids and epidermal delivery of HEV ORF2 DNA vaccine ... [more ▼]

A hepatitis E virus (HEV) vaccine would be valuable to reduce the morbidity and mortality associated with the infection in endemic areas. HEV pseudocapsids and epidermal delivery of HEV ORF2 DNA vaccine by gene-gun have been shown to confer protection against virus challenge in monkeys. Vectorization of a DNA vaccine by virus-like particles is a new immunization approach. We report here the successful immunization of mice with two ORF2 genes encapsidated into human papillomavirus type 31 virus-like particles. The HEV genes ORF2(112-660) and ORF2(112-608) were optimized for expression in mammalian cells and inserted in a baculovirus-derived vector for expression in insect cells. When expressed in Sf21 insect cells, ORF2(112-660) led to the production of irregular 15 nm particles that accumulated in the cytoplasm of the cells, whereas ORF2(112-608) induced the production of 18nm particles that were present in both the cell culture medium and the cell cytoplasm. Anti-HEV immune responses were higher for the 15 nm particles (HEV112-660) than that for to the 18 nm particles (HEV112-608). Delivery into mice of two HEV ORF2 genes via a papillomavirus VLP was very effective in the induction of anti-HEV antibodies. In addition, an effective immune response to human papillomavirus capsids occurred. These engineered pseudoviruses were thus demonstrated to induce immune responses to both hepatitis E virus and human papillomavirus when they were administered to mice intramuscularly. [less ▲]

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See detailInduction of apoptosis in HL-60 by a trachylobane diterpene from Croton Zambesicus
Block, Sébastien; Gillet, Marie-Claire ULg; Gerkens, Pascal et al

Poster (2002, September)

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See detailInduction of Apoptosis in Human Promyelocytic Leukemia Cells by a Natural Trachylobane Diterpene
Block, Sébastien; Gerkens, Pascal; Peulen, Olivier ULg et al

in Anticancer Research (2005), 25(1A), 363-368

Background: Trachylobane diterpenes are secondary metabolites quite rare in nature and their bioactivities are poorly known. Recently we have described the cytotoxic activity of ent- trachyloban-3‚-ol ... [more ▼]

Background: Trachylobane diterpenes are secondary metabolites quite rare in nature and their bioactivities are poorly known. Recently we have described the cytotoxic activity of ent- trachyloban-3‚-ol isolated from the leaves of Croton zambesicus, a plant used in African folk medicine. Materials and Methods: Cell viability on several cell lines, cell morphology, DNA laddering, annexin V and caspase-3 activation experiments were undertaken in order to analyse the cytotoxicty of trachylobane diterpene and to determine if this compound is able to induce apoptosis. Results: ent-trachyloban-3‚-ol exerts a dose-dependent cytotoxic effect and which varies between cell lines. Induction of apoptosis in HL-60 cells could be detected at a concentration of 50 ÌM after 24-h treatment. Conclusion: We show here, for the first time, that a trachylobane diterpene is able to induce apoptosis in human promyelocytic leukemia cells via caspase-3 activation in a concentration-dependent manner. [less ▲]

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See detailThe induction of beta-lactamases in Eubacteria
Joris, Bernard ULg; Dusart, Jean

in Uversky, Vladimir N.; Frère, Jean-Marie (Eds.) Beta-lactamases (2012)

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See detailInduction of Endothelial Cell Apoptosis by Solid Tumor Cells
Kebers, F.; Lewalle, J. M.; Desreux, Joëlle ULg et al

in Experimental Cell Research (1998), 240(2), 197-205

The mechanisms by which tumor cells extravasate to form metastasis remain controversial. Previous studies performed in vivo and in vitro demonstrate that the contact between tumor cells and the vascular ... [more ▼]

The mechanisms by which tumor cells extravasate to form metastasis remain controversial. Previous studies performed in vivo and in vitro demonstrate that the contact between tumor cells and the vascular wall impairs endothelium integrity. Here, we investigated the effect of breast adenocarcinoma MCF-7 cells on the apoptosis of human umbilical vein endothelial cells (HUVEC). TUNEL labeling, nuclear morphology, and DNA electrophoresis indicated that MCF-7 cells induced a two- to fourfold increase in HUVEC apoptosis. Caspase-3 activity was significantly enhanced. Neither normal cells tested (mammary epithelial cells, fibroblasts, leukocytes) nor transformed hematopoietic cells tested (HL60, Jurkat) induced HUVEC apoptosis. On the contrary, cells derived from solid tumors (breast adenocarcinoma, MDA-MB-231 and T47D; fibrosarcoma, HT 1080) had an effect similar to that of MCF-7 cells. The induction of apoptosis requires cell-to-cell contact, since it could not be reproduced by media conditioned by MCF-7 cells cultured alone or cocultured with HUVEC. Our results suggest that cells derived from solid tumors may alter the endothelium integrity by inducing endothelial cell apoptosis. On the contrary, normal or malignant leukocytes appear to extravasate by distinct mechanisms and do not damage the endothelium. Our data may lead to a better understanding of the steps involved in tumor cell extravasation. [less ▲]

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See detailThe induction of flowering in Lolium temulentum L.
Périlleux, Claire ULg

Conference (1993)

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See detailInduction of long-lasting changes of visual cortex excitability by five daily sessions of repetitive transcranial magnetic stimulation (rTMS) in healthy volunteers and migraine patients
Fumal, Arnaud ULg; Coppola, G.; Bohotin, V. et al

in Cephalalgia : An International Journal of Headache (2006), 26(2), 143-149

We have shown that in healthy volunteers (HV) one session of 1 Hz repetitive transcranial magnetic stimulation (rTMS) over the visual cortex induces dishabituation of visual evoked potentials (VEPs) on ... [more ▼]

We have shown that in healthy volunteers (HV) one session of 1 Hz repetitive transcranial magnetic stimulation (rTMS) over the visual cortex induces dishabituation of visual evoked potentials (VEPs) on average for 30 min, while in migraineurs one session of 10 Hz rTMS replaces the abnormal VEP potentiation by a normal habituation for 9 min. In the present study, we investigated whether repeated rTMS sessions (1 Hz in eight HV; 10 Hz in eight migraineurs) on 5 consecutive days can modify VEPs for longer periods. In all eight HV, the 1 Hz rTMS-induced dishabituation increased in duration over consecutive sessions and persisted between several hours (n = 4) and several weeks (n = 4) after the fifth session. In six out eight migraineurs, the normalization of VEP habituation by 10 Hz rTMS lasted longer after each daily stimulation but did not exceed several hours after the last session, except in two patients, where it persisted for 2 days and 1 week. Daily rTMS can thus induce long-lasting changes in cortical excitability and VEP habituation pattern. Whether this effect may be useful in preventative migraine therapy remains to be determined. [less ▲]

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See detailInduction of membrane-type matrix metalloproteinase 1 (MT1-MMP) expression in human fibroblasts by breast adenocarcinoma cells.
Polette, M.; Gilles, Christine ULg; Marchand, V. et al

in Clinical & Experimental Metastasis (1997), 15(2), 157-63

Membrane-type matrix metalloproteinase 1 (MT1-MMP) has been recently described as an activator of proMMP-2 (MMP-2) which is involved in tumor invasion. We have shown by in situ hybridization that MT1-MMP ... [more ▼]

Membrane-type matrix metalloproteinase 1 (MT1-MMP) has been recently described as an activator of proMMP-2 (MMP-2) which is involved in tumor invasion. We have shown by in situ hybridization that MT1-MMP is produced by stromal cells in close contact to preinvasive and invasive tumor cells of breast carcinomas. Of particular interest was the observation that some fibroblasts express this enzyme in focal areas in preinvasive lesions, suggesting that particular tumor cells may stimulate fibroblasts to produce MT1-MMP. We have therefore compared the ability of two different breast cancer cell lines, one non-invasive (MCF7) and one invasive (MDA-MB-231) to stimulate MT1-MMP production in human fibroblasts with consequent proMMP-2-activation. The MDA-MB-231 conditioned medium induced MT1-MMP mRNAs in human fibroblasts and a parallel activation of proMMP-2 whereas MCF7 conditioned medium did not have any effect. These results suggest the existence of soluble factor(s) secreted by invasive or some preinvasive breast tumor cells which stimulate fibroblasts to produce and activate MMPs, and emphasize the cooperation between cancer and stromal cells in tumor invasion. [less ▲]

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See detailInduction of nuclear factor-kappaB and its downstream genes by TNF-alpha and IL-1beta has a pro-apoptotic role in pancreatic beta cells
Ortis, Fernanda; Pirot, P.; Naamane, N. et al

in Diabetologia (2008), 51

IL-1beta and TNF-alpha contribute to pancreatic beta cell death in type 1 diabetes. Both cytokines activate the transcription factor nuclear factor-kappaB (NF-kappaB), but recent observations suggest that ... [more ▼]

IL-1beta and TNF-alpha contribute to pancreatic beta cell death in type 1 diabetes. Both cytokines activate the transcription factor nuclear factor-kappaB (NF-kappaB), but recent observations suggest that NF-kappaB blockade prevents IL-1beta + IFN-gamma- but not TNF-alpha + IFN-gamma-induced beta cell apoptosis. The aim of the present study was to compare the effects of IL-1beta and TNF-alpha on cell death and the pattern of NF-kappaB activation and global gene expression in beta cells. METHODS: Cell viability was measured after exposure to IL-1beta or to TNF-alpha alone or in combination with IFN-gamma, and blockade of NF-kappaB activation or protein synthesis. INS-1E cells exposed to IL-1beta or TNF-alpha in time course experiments were used for IkappaB kinase (IKK) activation assay, detection of p65 NF-kappaB by immunocytochemistry, real-time RT-PCR and microarray analysis. RESULTS: Blocking NF-kappaB activation protected beta cells against IL-1beta + IFNgamma- or TNFalpha + IFNgamma-induced apoptosis. Blocking de novo protein synthesis did not increase TNF-alpha- or IL-1beta-induced beta cell death, in line with the observations that cytokines induced the expression of the anti-apoptotic genes A20, Iap-2 and Xiap to a similar extent. Microarray analysis of INS-1E cells treated with IL-1beta or TNF-alpha showed similar patterns of gene expression. IL-1beta, however, induced a higher rate of expression of NF-kappaB target genes putatively involved in beta cell dysfunction and death and a stronger activation of the IKK complex, leading to an earlier translocation of NF-kappaB to the nucleus. CONCLUSIONS/INTERPRETATION: NF-kappaB activation in beta cells has a pro-apoptotic role following exposure not only to IL-1beta but also to TNF-alpha. The more marked beta cell death induced by IL-1beta is explained at least in part by higher intensity NF-kappaB activation, leading to increased transcription of key target genes. [less ▲]

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See detailInduction of phenolic compounds in two cultivars of cucumber by treatment of healthy and powdery mildew-infected plants with extracts of Reynoutria sachalinensis
Daayf, Fouad; Ongena, MARC ULg; Boulanger, Renald et al

in Journal of Chemical Ecology (2000), 26

Accumulation of phenolic compounds (p-coumaric, caffeic, and ferulic acids and p-coumaric acid methyl ester) was followed in susceptible (Mustang) and tolerant (Flamingo) cucumber (Cucumis sativus ... [more ▼]

Accumulation of phenolic compounds (p-coumaric, caffeic, and ferulic acids and p-coumaric acid methyl ester) was followed in susceptible (Mustang) and tolerant (Flamingo) cucumber (Cucumis sativus) cultivars. The objective was to determine whether these compounds played a role in resistance against powdery mildew following a prophylactic treatment with Milsana (leaf extracts from the giant knot weed Reynoutria sachalinensis, polygonaceae). This treatment significantly reduced the incidence of powdery mildew in both cultivars. Phenolic compounds were extracted from leaves. In the hydrolyzed fraction containing phenolic aglycones, levels of p-coumaric, caffeic, and ferulic acids and of p-coumaric acid methyl ester increased in all treatments (with leaf extracts of R. Sachalinensis, powdery mildew, or both) except the control, one or two days after treatment. In the fraction containing free phenolics, from the tested compounds, only ferulic acid showed an increase in cv. Flamingo (tolerant), and was particularly evident following treatments. On the other hand, the amounts of hydroxycinnamic acids increased rapidly in the two cultivars following Milsana treatment, suggesting their role in disease reduction. All compounds showed antifungal activity when tetsed against common pathogens of cucumber (Botrytis cinerea, Pythium ultimum, and P. aphanidermatum), but in general methyl esters were more fungitoxic than their corresponding free acids. This study suggests that cucumber is able to release antifungal compounds that are instrumental in repressing powdery mildew infection. This response is seemingly independent from the level of genetic resistance associated with each cultivar. [less ▲]

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See detailInduction of photosynthetic electron transfer upon anoxia in Chlamydomonas: role of hydrogenase activity and PSI-cyclic electron flow
Godaux, Damien ULg; Berne, Nicolas ULg; Remacle, Claire ULg et al

Poster (2013)

In Chlamydomonas reinhardtii, anoxic environment leads to the expression of various fermentative/anaerobic pathways. Among them, oxygen-sensitive hydrogenases catalyze the reduction of protons from ... [more ▼]

In Chlamydomonas reinhardtii, anoxic environment leads to the expression of various fermentative/anaerobic pathways. Among them, oxygen-sensitive hydrogenases catalyze the reduction of protons from reduced ferredoxin resulting in the production of molecular hydrogen. A possible role of chloroplast hydrogenase in the anaerobic induction of photosynthesis has been suggested forty years ago (Kessler, 1973) but never further explored. H2 evolution is a minor and transient phenomenon which is often considered as a safety mechanism to protect photosynthetic chain from overreduction (Melis and Happe, 2001; Hemschemeier et al., 2009). Recent data about hydrogen production in a pgrl1 (Proton Gradient Regulation like1) mutant with limited capacity for PSI-cyclic electron flow (CEF) also suggested a participation of CEF in photosynthesis reactivation after short dark-anoxic periods (Tolleter et al., 2011). Because H2 evolution is improved in pgrl1 mutant, authors came to the conclusion that H+ gradient generated by CEF strongly prevents electron supply to the hydrogenase and is thus a limitating factor for hydrogen production. The aim of our work is to further study the role of hydrogenase and CEF in the photosynthesis reactivation process after short (~1h) or long (>18h) dark-anoxic periods. We take advantage of the availability of hydrogenase-deficient mutants (hydEF, hydG) (Posewitz et al., 2005; Godaux et al., 2013) and above-mentioned CEF-deficient pgrl1 mutant. Light-induced photosynthetic electron transfer is studied by measuring hydrogen and oxygen evolution, as well as by following kinetics of chlorophyll fluorescence emission and P700 oxidoreduction. Firstly, we show that during the induction of photosynthesis after long dark-anoxic periods, there is a linear relationship between hydrogen evolution, PSI and PSII activities, meaning that an hydrogenase- dependent photosynthetic linear electron flow (LEF) mainly operates. Moreover, PSI and PSII photochemical yield are almost null in hydrogenase-deficient mutants. We conclude that hydrogenase is the main sink for photosynthetic electrons upon illumination after prolonged anoxia. Similarly, a linear correlation can be established between hydrogen evolution, hydrogenase expression/activity, and PSI or PSII photochemical yields upon adaptation to anoxia. In the next part of our work, we focus our attention on the role of PSI-CEF in the induction of photosynthesis upon anoxia. Combined measurements of PSI/PSII activities and O2/H2 evolution show that induction of photosynthesis is delayed in a Pgrl1-deficient strain. In absence of Pgrl1 protein, the H+ gradient is also lower and we thus propose that a lack of ATP is responsible for the delayed Calvin cycle reactivation, so that hydrogen production can be achieved for a longer time without inactivation of hydrogenase activity by evolved O2. These results are in good agreement with other results obtained by our group, demonstrating that state transition is a critical process for induction of photosynthesis in anoxia (Ghysels et al., accepted). In conclusion, a Pgrl1-dependent CEF seems to be in first importance to photosynthesis induction after one hour of dark-anaerobiosis adaptation, acting together with an hydrogenase dependant LEF to set favourable conditions for Calvin cycle activation. [less ▲]

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See detailInduction of potato (Solanum tuberosum L.) tuber sprouting by hydrogen peroxide.
Bajji, M.; M'Hamdi, M.; Gastiny, F. et al

in Free Radical Research (2003), 37

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See detailInduction of protective immunity to bovine herpesvirus type 1 in cattle by intranasal administration of replication-defective human adenovirus type 5 expressing glycoprotein gC or gD
Gogev, S.; Vanderheijden, N.; Lemaire, Mylène et al

in Vaccine (2002), 20(9-10), 1451-1465

Replication-defective human adenoviruses type 5 (HAd5) expressing the bovine herpesvirus type 1 (BHV-1) glycoprotein gC or gD under the control of the human cytomegalovirus immediate-early promoter ... [more ▼]

Replication-defective human adenoviruses type 5 (HAd5) expressing the bovine herpesvirus type 1 (BHV-1) glycoprotein gC or gD under the control of the human cytomegalovirus immediate-early promoter/enhancer (AdCMVgC or AdCMVgD) or the 5' regulatory region of the human desmin gene (AdDESMgC or AdDESMgD) were generated. A preliminary experiment performed on rabbits showed that the intranasal administration of AdCMV elicited higher levels of BHV-1 neutralizing antibodies than the intramuscular administration of AdDESM. The obtained results allowed to select the replication-defective AdCMVgC and AdCMVgD for further assessment of their potential as a recombinant vaccine in cattle. Calves were injected intranasally twice 3 weeks apart with either AdCMVgC or AdCMVgD or a combination of these two recombinants or a commercially available live vaccine for comparison. The highest BHV-1 neutralizing antibody titres were obtained with AdCMVgD followed by the live vaccine and to a lower extent with the combination of the two recombinants (AdCMVgC+AdCMVgD). Calves were protected against intranasal BHV-1 challenge performed 3 weeks after the second immunization. In view of the obtained results, recombinant HAd5 may be developed as an intranasal vaccine vector in cattle administrated either alone or sequentially with non-human adenovirus-based vectors. [less ▲]

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See detailInduction of Sparc by Vegf in Human Vascular Endothelial Cells
Kato, Y.; Lewalle, J. M.; Baba, Y. et al

in Biochemical and Biophysical Research Communications (2001), 287(2), 422-6

SPARC/osteonectin/BM-40 is a matricellular protein that is thought to be involved in angiogenesis and endothelial barrier function. Previously, we have detected high levels of SPARC expression in ... [more ▼]

SPARC/osteonectin/BM-40 is a matricellular protein that is thought to be involved in angiogenesis and endothelial barrier function. Previously, we have detected high levels of SPARC expression in endothelial cells (ECs) adjacent to carcinomas of kidney and tongue. Although SPARC-derived peptide showed an angiogenic effect, intact SPARC itself inhibited the mitogenic activity of vascular endothelial growth factor (VEGF) for ECs by the inhibiting phosphorylation of flt-1 (VEGF receptor 1) and subsequent ERK activation. Thus, the role of SPARC in tumor angiogenesis, stimulation or inhibition, is still unclear. To clarify the role of SPARC in tumor growth and progression, we determined the effect of VEGF on the expression of SPARC in human microvascular EC line, HMEC-1, and human umbilical vein ECs. VEGF increased the levels of SPARC protein and steady-state levels of SPARC mRNA in serum-starved HMEC-1 cells. Inhibitors (SB202190 and SB203580) of p38, a mitogen-activated protein (MAP) kinase, attenuated VEGF-stimulated SPARC production in ECs. Since intact SPARC inhibits phosphorylation ERK MAP kinase in VEGF signaling, it was suggested that SPARC plays a dual role in the VEGF functions, tumor angiogenesis, and extravasation of tumors mediated by the increased permeability of endothelial barrier function. [less ▲]

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