Byrne C.,University Pierre and Marie Curie |
Miclet E.,University Pierre and Marie Curie |
Broutin I.,University of Paris Descartes |
Gallo D.,Institute Meurice |
And 5 more authors.
Chirality | Year: 2013
Protein-protein interactions are crucial for signal transductions required for cell differentiation and proliferation. Their modulation is therefore key to the development of therapeutic alternatives, particularly in the context of cancer. According to literature data, the polyproline-rich nuclear receptor coactivators PNRC and PNRC2 interact with estrogen receptor (ERα) through their PxxP SH3-binding motifs. In a search to identify the molecular features governing this interaction, we explored using electronic circular dichroism (ECD) spectroscopy and molecular dynamics (MD) calculations, the capacity of a range of putative biologically active peptides derived from these proteins and containing this PxxP motif(s) to form polyproline II (PPII) domains. An additional more exhaustive structural study on a lead PPII peptide was also performed using 2D nuclear magnetic resonance (NMR) spectroscopy. With the exception of one of all the investigated peptides (PNRC-D), binding assays failed to detect any affinity for Grb2 SH3 domains, suggesting that PPII motifs issued from Grb2 antagonists have a binding mode distinct from those derived from Grb2 agonists. Instead, the peptides revealed a competitive binding ability against a synthetic peptide (ERα17p) with a putative PPII-cognate domain located within a coregulator recruitment region of ERα (AF-2 site). Our work, which constitutes the first structure-related interaction study concerning PNRC and PNRC2, supports not only the existence of PxxP-induced PPII sequences in these coregulators, but also confirms the presence of a PPII recognition site in the AF-2 of the steroid receptor ERα, a region important for transcription regulation. Chirality 25:628-642, 2013. © 2013 Wiley Periodicals, Inc. © 2013 Wiley Periodicals, Inc.
Blavier J.,Roosevelt University |
Verbanck M.A.,Free University of Colombia |
Craddock F.,Roosevelt University |
Craddock F.,Free University of Colombia |
And 6 more authors.
Journal of Water Process Engineering | Year: 2014
Riverbed filtration is a promising alternative method of drinking water production for developing countries which has been little investigated and is still poorly characterized. As it offers advantages on riverbank filtration in terms of production yield, riverbed filtration needs to be more deeply defined. Riverbed filtration systems set up in Camiri (southeastern Bolivia) were characterized by collecting field data about the systems production yields and the produced water quality. The first objective of this work is to propose a method for the prediction of the production yield of the riverbed filtration systems in Camiri. The second objective is to perform a general review of the water quality of the filtered water provided by these systems.The water quality study results show that the Camiri's riverbed filtration systems act like filters, efficiently removing turbidity and microorganisms. Regarding the systems production yield, the field study results obtained are successfully compared to those predicted by the method developed in this work, based on the evaluation, in laboratory, of the characteristic permeabilities of the porous media of the studied systems. This comparison highlights the fact that a clogging of a part of the riverbed might be the reason of the observed drop over time of the production yield of Camiri's riverbed filtration systems. © 2014 Elsevier Ltd.
Martinelli L.,Eng-Tips |
Talvy S.,Eng-Tips |
Liegeois S.,Eng-Tips |
Liegeois S.,Institute Meurice |
And 3 more authors.
Chemical Engineering Science | Year: 2011
This paper proposes a single-phase flow model to simulate the flow induced in a liquid by the injection of gas dispersed in the form of a bubble curtain. It aims at predicting macroscopic liquid flow and mixing time. This single-phase flow model is developed as an alternative to two-phase flow models. The model is based on the assumption that the liquid flow is induced by a density imbalance between the bulk zone and the bubble curtain zone. The density in the bulk is set to the water density while the density in the bubble curtain corresponds to the air-water mixture density and is assessed by numerical simulations, thanks to an iterative procedure. Only the knowledge of the injected air flow rate and the bubble liquid relative velocity is required. The single-phase flow model is applied to assess the liquid flow and the mixing in open quarries having a complex geometry. The liquid velocities and the flow structure in the open quarries simulated with the single-phase flow model are in good agreement with those predicted by numerical simulations based on a two-phase flow model. © 2011 Elsevier Ltd.
Lempereur M.,Institute Meurice |
Majewska C.,Institute Meurice |
Brunquers A.,Institute Meurice |
Wongpramud S.,Institute Meurice |
And 5 more authors.
International Journal of Endocrinology | Year: 2016
Tetrahydro-iso-alpha acids commonly called THIAA or Tetra are modified hop acids extracted from hop (Humulus lupulus L.) which are frequently used in brewing industry mainly in order to provide beer bitterness and foam stability. Interestingly, molecular structure of tetrahydro-iso-alpha acids is close to a new type of estrogen receptor alpha (ERα) antagonists aimed at disrupting the binding of coactivators containing an LxxLL motif (NR-box). In this work we show that THIAA decreases estradiol-stimulated proliferation of MCF-7 (ERα-positive breast cancer cells). Besides, we show that it inhibits ERα transcriptional activity. Interestingly, this extract fails to compete with estradiol for ERα binding and does not significantly impact the receptor turnover rate in MCF-7 cells, suggesting that it does not act like classical antiestrogens. Hence, we demonstrate that THIAA is able to antagonize ERα estradiol-induced recruitment of the LxxLL binding motif. © 2016 Maëlle Lempereur et al.
PubMed | Institute Meurice and Yakima Chief Hopunion LLC
Type: | Journal: International journal of endocrinology | Year: 2016
Tetrahydro-iso-alpha acids commonly called THIAA or Tetra are modified hop acids extracted from hop (Humulus lupulus L.) which are frequently used in brewing industry mainly in order to provide beer bitterness and foam stability. Interestingly, molecular structure of tetrahydro-iso-alpha acids is close to a new type of estrogen receptor alpha (ER) antagonists aimed at disrupting the binding of coactivators containing an LxxLL motif (NR-box). In this work we show that THIAA decreases estradiol-stimulated proliferation of MCF-7 (ER-positive breast cancer cells). Besides, we show that it inhibits ER transcriptional activity. Interestingly, this extract fails to compete with estradiol for ER binding and does not significantly impact the receptor turnover rate in MCF-7 cells, suggesting that it does not act like classical antiestrogens. Hence, we demonstrate that THIAA is able to antagonize ER estradiol-induced recruitment of the LxxLL binding motif.
Becu M.,Eng-Tips |
Fonoll J.R.,Eng-Tips |
Hospied E.,Eng-Tips |
Liegeois S.,Institute Meurice |
And 2 more authors.
Biotechnology, Agronomy and Society and Environment | Year: 2010
In the food industry, the production process is often established in an empirical way, according to rules of good practice. These methods present gaps, in particular at the level of the production regularity. To model and optimize the processes, it is highly useful to determine the physico-chemical properties of the product. In this work, chocolate and margarine are studied, both aiming direct industrial application but also aiming a general enhancement of rheological mechanism understanding. Indeed, the chocolate is a suspension of solid particles in cocoa butter and the margarine is a water-in-oil emulsion. Rheological behavior of those fluids is therefore relying on different key phenomena. In this work the flow behavior of both products is characterized and a mathematical model describing the rheological behavior of chocolate is developed. For chocolate, the goal is to model the tempering process. To establish the rheological behavior of chocolate, viscosity measurements were realized in a SEARLE VT550 viscometer using a bob and cup geometry. To build the mathematical law, general tests following the International Office of Cocoa, Chocolate and Sugar Confectionery (IOCCC) recommended method (Servais et al., 2004) were performed. The obtained rheogram shows that the chocolate has a slightly thixotropic behavior. More focus is set on a smaller range of shear rate important for the industrial application (Debaste et al., 2008). Measures for various temperatures and various quantities of cocoa butter were realized. The results show a classical shear-thinning behavior. Further, a statistical analysis of the results was made to determine the parameters of a power-law describing this behavior. It appears that temperature and cocoa butter fraction have no influence on the exponent but well on the consistency parameter. For margarine, the goal is to model the flow in resting tubes, the last step in the industrial production (Herman et al., 2008). To determine the rheological behavior of the margarine two kinds of devices were used. First the SEARLE VT550 viscometer with a four blades impeller was used. And the results were not satisfying because the measured viscosity was often nulls. We suppose that the sample was broken into two blocks, one between the blades of the impeller and a second outside of the impeller. A HAAK MARS rheometer with a plate-plate geometry was also used. In both experiments we evaluate how a change of 1°C can affect the viscosity of margarine. The obtained flow curves show that the margarine has a plastic and thixotropic behavior and that a variation of 1°C affects margarine's rheology. With the chocolate rheological law, the perspective is to get a general model for concentrated suspensions. And for margarine, more measures with an adapted viscometer should be done to build a model.
Libouton M.,Institute Meurice |
Daoust D.,Catholic University of Louvain |
Sclavons M.,Catholic University of Louvain |
Biebuyck J.J.,Catholic University of Louvain |
Van Nedervelde L.,Institute Meurice
Journal of the American Society of Brewing Chemists | Year: 2012
For decades, kieselguhr has been the most common filter aid for beer filtration. However, costs for disposal are severely increasing and brewers today are concerned about replacing kieselguhr filtration by a greener technology. Filtration trials were carried out with the regenerable filter aid oxidized high-density polyethylene (OxPE) on a pilot-scale candle filter using green lager beer from settling tanks. OxPE has an average particle size distribution of 37 μm and its outer surface presents nodular structures. The porosity of the OxPE media is 0.6 compared with 0.85 for kieselguhr. OxPE retains a good amount of haze and yeast cells without clogging; however, the expected clarity was reached only when using Brewtan. The use of polyvinyl-polypyrrolidone (PVPP) mixed with the OxPE filter aid (25/75%) showed the best results for filtration because of the shape of PVPP particles and their slight compressibility. Regeneration is one of the most important steps to achieve because the filter aid has to be reused as many times as possible while keeping its properties of retention toward haze and yeast cells. OxPE proved to have very good resistance to aggressive regeneration conditions, and filtration trials carried out after such an operation confirmed this. © 2012 American Society of Brewing Chemists, Inc.
Ploegaerts G.,Institute Meurice |
Desmet C.,Institute Meurice |
Van krieken M.,Institute Meurice
Journal of Food Composition and Analysis | Year: 2016
Excessive salt consumption has recently awakened considerable worldwide interest because of its serious health implications. Consequently, European authorities have stated that salt content has to be clearly indicated on the food labels. In order to choose one protocol to determine the sodium content, three preparation methods (dispersion in water, wet digestion and dry ashing) and four analytical techniques (flame atomic absorption spectrometry (FAAS), flame atomic emission spectrometry (FAES), inductively coupled plasma-atomic emission spectrometry (ICP-AES) and thermometric endpoint titrimetry (TET)) have been compared. As indirect methods based on the assay of chloride could lead to wrong results, especially when food additives are involved in the recipes, it was chosen not to include them in this study. After an evaluation of analytical parameters, each combination, preparation mode and analytical technique, was tested with samples of tomato ketchup sauce. If all of them can fit to the purpose (recovery rates close to 100% and low dispersion of the results), two possibilities were pointed out: dry ashing with FAAS and the dispersion combined with TET. © 2015 Elsevier Inc.