References of "Gerkens, Pascal"
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See detailApoptosis and cytolysis induced by giganteosides and hederacolchisides in HL-60 cells
Gerkens, Pascal; Dobson, Rowan ULg; tabatadze, Nino et al

in Anticancer Research (2007), 27

The viability, cytolysis and apoptosis-mediated cellular death induced by giganteosides D and E (Gig-D and Gig-E) and hederacolchisides A and A1 (Hcol-A and Hcol- A1) were analysed in HL-60 cells ... [more ▼]

The viability, cytolysis and apoptosis-mediated cellular death induced by giganteosides D and E (Gig-D and Gig-E) and hederacolchisides A and A1 (Hcol-A and Hcol- A1) were analysed in HL-60 cells. Materials and Methods: the end-point metabolic (WST1) and lactate dehydrogenase (LDH) assays were used. Cell cycle analysis and apoptosis were measured by flow cytometry, DNA laddering and caspase 3 analyses. Results: the HL-60 cell line was more sensitive to Hcol-A1 and Gig-D (IC50 3-5 ÌM) than to Gig-E and Hcol-A (IC50 8-13 ÌM; WST1 assay). This was related to LDH release. The induction of apoptosis could be detected without caspase 3 activation after 24 h of treatment. DNA fragmentation could be detected only with Gig-D. With Hcol- A1 and Gig-D, an accumulation of cells in the S-phase and an increase of cells in sub-G1 peak were observed. By the annexinV-fluorescein isothiocyanate (FITC)/7-aminoactinomycin D (AAD) assay, the majority of cells were in late apoptosis with Gig-D, and in necrosis with Hcol-A1. Conclusion: Hcol-A1 is more cytotoxic than Gig-D, followed by Gig-E and finally Hcol-A. This is related to a membrane permeabilization effect, leading to cytolysis [less ▲]

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See detailCytotoxic triterpenoid saponins from the roots of Cephalaria gigantea
Tabatadze, Nino; Elias, Riad; Faure, Robert et al

in Chemical & Pharmaceutical Bulletin (2007), 55(1), 102-105

Three new oleanane-type saponins, giganteosides L (1)(I), M (2) and N (3) along with eight known ones were isolated from the roots of Cephalaria gigantea. Their structures were established as 3-O-[-D ... [more ▼]

Three new oleanane-type saponins, giganteosides L (1)(I), M (2) and N (3) along with eight known ones were isolated from the roots of Cephalaria gigantea. Their structures were established as 3-O-[-D-galactopyranosyl-(12)--D-glucuronopyranosyl]-28-O-[-D-glucopyranosyl-(16)--D-glucopyranosyl]-oleanolic acid, 3-O-[-D-galactopyranosyl-(12)--D-glucuronopyranosyl]-28-O-[-D-glucopyranosyl-(16)--D-glucopyranosyl]-hederagenin, 3-O-[-L-rhamnopyranosyl-(12)--D-glucuronopyranosyl]-28-O-[-D-glucopyranosyl-(16)--D-glucopyranosyl]-hederagenin, resp., by means of spectroscopic methods (1D and 2D NMR, HR-ESI-MS). Cytotoxic activity of monodesmosides was investigated in vitro using three cancer cell lines, namely, human non pigmented melanoma MEL-5 and human leukemia HL-60. Giganteosides D (4) and E (5) showed antiproliferative effect on human cell lines with IC50 values in the range 3.15-7.5 M. [less ▲]

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See detailSaccharomyces cerevisiae mitoproteome plasticity in response to recombinant alternative ubiquinol oxidase
Mathy, Grégory ULg; Navet, Rachel ULg; Gerkens, Pascal et al

in Journal of Proteome Research (2006), 5(2), 339-348

The energy-dissipating alternative oxidase (AOX) from Hansenula anomala, was expressed in Saccharomyces cerevisiae. The recombinant AOX was functional. A comparative analysis by two-dimensional ... [more ▼]

The energy-dissipating alternative oxidase (AOX) from Hansenula anomala, was expressed in Saccharomyces cerevisiae. The recombinant AOX was functional. A comparative analysis by two-dimensional differential in-gel electrophoresis (2D-DIGE) of mitochondrial protein patterns found in wild-type and recombinant AOX strains was performed. 60 proteins exhibiting a significant difference in their abundance were identified. Interestingly, proteins implicated in major metabolic pathways such as Krebs cycle and amino acid biosynthesis were up-regulated. Surprisingly, an up-regulation of the respiratory-chain complex III was associated with a down-regulation of the ATP synthase complex. [less ▲]

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See detailUncoupling protein 1 affects the yeast mitoproteome and oxygen free radical production
Douette, Pierre ULg; Gerkens, Pascal; Navet, Rachel ULg et al

in Free Radical Biology & Medicine (2006), 40(2), 303-315

Uncoupling protein I (UCP1) is a mitochondrial inner membrane protein that dissipates the proton electrochemical gradient built up by the respiratory chain. its activity is stimulated by free fatty acids ... [more ▼]

Uncoupling protein I (UCP1) is a mitochondrial inner membrane protein that dissipates the proton electrochemical gradient built up by the respiratory chain. its activity is stimulated by free fatty acids and inhibited by purine nucleotides. Here we investigated how active and regulated recombinant UCP1 expressed in yeast at similar to 1 and similar to 10 mu g/mg of total mitochondrial proteins induced changes in the mitochondrial proteome and in oxygen free radical production. Using two-dimensional differential in-gel electrophoresis (2D-DIGE), we found that most of the proteins involved in the response to ectopically expressed UCP1 are related to energy metabolism. We also quantified the cellular H2O2 release in the absence or in the presence of UCP1. Our results suggest that UCP1 has a dual influence on free radical generation. On one side, FFA-activated UCP1 was able to decrease the superoxide anion production, demonstrating that a decrease in the generation of reactive oxygen species is an obligatory outcome of UCP1 activity even in a heterologous context. On the other side, an increase in UCP1 content was concomitant with an increase in the basal release of superoxide anion by mitochondria as a side consequence of the overall increase in oxidative metabolism. (c) 2005 Elsevier Inc. All rights reserved. [less ▲]

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See detailProteomics in Myzus persicae: effect of aphid host plant switch.
Francis, Frédéric ULg; Gerkens, Pascal; Harmel, Nicolas ULg et al

in Insect Biochemistry and Molecular Biology (2006), 36(3), 219-27

Chemical ecology is the study of how particular chemicals are involved in interactions of organisms with each other and with their surroundings. In order to reduce insect attack, plants have evolved a ... [more ▼]

Chemical ecology is the study of how particular chemicals are involved in interactions of organisms with each other and with their surroundings. In order to reduce insect attack, plants have evolved a variety of defence mechanisms, both constitutive and inducible, while insects have evolved strategies to overcome these plant defences (such as detoxification enzymes). A major determinant of the influence of evolutionary arms races is the strategy of the insect: generalist insect herbivores, such as Myzus persicae aphid, need more complex adaptive mechanisms since they need to respond to a large array of different plant defensive chemicals. Here we studied the chemical ecology of M. persicae associated with different plant species, from Brassicaceae and Solanaceae families. To identify the involved adaptation systems to cope with the plant secondary substances and to assess the differential expression of these systems, a proteomic approach was developed. A non-restrictive approach was developed to identify all the potential adaptation systems toward the secondary metabolites from host plants. The complex protein mixtures were separated by two-dimensional electrophoresis methods and the related spots of proteins significantly varying were selected and identified by mass spectrometry (ESI MS/MS) coupled with data bank investigations. Fourteen aphid proteins were found to vary according to host plant switch; ten of them were down regulated (proteins involved in glycolysis, TCA cycle, protein and lipid synthesis) while four others were overexpressed (mainly related to the cytoskeleton). These techniques are very reliable to describe the proteome from organisms such as insects in response to particular environmental change such as host plant species of herbivores. [less ▲]

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See detailFrom dormant to germinating spores of Streptomyces coelicolor A3(2): new perspectives from the crp null mutant.
Piette, André ULg; Derouaux, Adeline ULg; Gerkens, Pascal et al

in Journal of Proteome Research (2005), 4(5), 1699-708

The complete understanding of the morphological differentiation of streptomycetes is an ambitious challenge as diverse sensors and pathways sensitive to various environmental stimuli control the process ... [more ▼]

The complete understanding of the morphological differentiation of streptomycetes is an ambitious challenge as diverse sensors and pathways sensitive to various environmental stimuli control the process. Germination occupies a particular position in the life cycle as the good achievement of the process depends on events occurring both during the preceding sporulation and during germination per se. The cyclic AMP receptor protein (crp) null mutant of Streptomyces coelicolor, affected in both sporulation and germination, was therefore presented as a privileged candidate to highlight new proteins involved in the shift from dormant to germinating spores. Our multidisciplinary approach-combining in vivo data, the analysis of spores morphological properties, and a proteome study-has shown that Crp is a central regulatory protein of the life cycle in S. coelicolor; and has identified spores proteins with statistically significant increased or decreased expression that should be listed as priority targets for further investigations on proteins that trigger both ends of the life cycle. [less ▲]

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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 detailAphid adaptation to plant defence system
Francis, Frédéric ULg; Harmel, Nicolas ULg; Gerkens, Pascal et al

in Abstract book (2005)

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See detailIdentification of Potential Biomarkers of Human Peripheral Blood Mononuclear Cell intoxication by dioxins
Brenez, Cécile; Cellier, Nicolas; Gerkens, Pascal et al

in Organohalogen Compounds (2005), 67

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See detailSteatosis-induced proteomic changes in liver mitochondria evidenced by two-dimensional differential in-gel electrophoresis
Douette, Pierre ULg; Navet, Rachel ULg; Gerkens, Pascal et al

in Journal of Proteome Research (2005), 4(6), 2024-2031

Steatosis encompasses the accumulation of droplets of fats into hepatocytes. In this work, we performed a comparative analysis of mitochondrial protein patterns found in wild-type and steatosis-affected ... [more ▼]

Steatosis encompasses the accumulation of droplets of fats into hepatocytes. In this work, we performed a comparative analysis of mitochondrial protein patterns found in wild-type and steatosis-affected liver using the novel technique two-dimensional differential in-gel electrophoresis (2D-DIGE). A total of 56 proteins exhibiting significant difference in their abundances were unambiguously identified. Interestingly, major proteins that regulate generation and consumption of the acetyl-CoA pool were dramatically changed during steatosis. Many proteins involved in the response to oxidative stress were also affected. [less ▲]

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See detailProteomic approach to investigate plant – aphid interactions
Francis, Frédéric ULg; Gerkens, Pascal; De Pauw, Edwin ULg et al

Conference (2005)

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See detailIdentification of specific biomarkers related to the effects of pollutants on the immune system of marine mammals
Brenez, Cécile; Gerkens, Pascal; Jauniaux, Thierry ULg et al

Poster (2004)

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See detailIdentification of specific biomarkers related to the effects of pollutants on the immune system of marine mammals
Brenez, Cécile; Gerkens, Pascal; Jauniaux, Thierry ULg et al

Poster (2003, December)

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See detailActivités cytotoxiques et apoptotiques de gigantéosides D et E isolés de Cephalaria gigantea
Gerkens, Pascal; Frederich, Michel ULg; Mshvildadze, Vakhtang et al

Poster (2002, September)

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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 detailAspects quantitatifs de la spectrométrie de masse des biomolécules
De Pauw, Edwin ULg; Gabelica, Valérie ULg; Gillet, Marie-Claire ULg et al

Conference (2002, March)

Spectrométrie de masse en 2002 : plus haut, plus vite… mais jusqu’où et pourquoi faire ?

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