Search

Breast cancer is often sporadic due to several factors. Among them, the deregulation of epigenetic proteins may be involved. TIP60 or KAT5 is an acetyltransferase that regulates gene transcription through the chromatin structure. This pleiotropic protein acts in several cellular pathways by acetylating proteins. RNA and protein expressions of TIP60 were shown to decrease in some breast cancer subtypes, particularly in triple-negative breast cancer (TNBC), where a low expression of TIP60 was exhibited compared with luminal subtypes. In this study, the inhibition of the residual activity of TIP60 in breast cancer cell lines was investigated by using two chemical inhibitors, TH1834 and NU9056, first on the acetylation of the specific target, lysine 4 of histone 3 (H3K4) by immunoblotting, and second, by chromatin immunoprecipitation (ChIP)-qPCR (-quantitative Polymerase Chain Reaction). Subsequently, significant decreases or a trend toward decrease of H3K4ac in the different chromatin compartments were observed. In addition, the expression of 48 human nuclear receptors was studied with TaqMan Low-Density Array in these breast cancer cell lines treated with TIP60 inhibitors. The statistical analysis allowed us to comprehensively characterize the androgen receptor and NR3C2 receptors in TNBC cell lines after TH1834 or NU9056 treatment. The understanding of the residual activity of TIP60 in the evolution of breast cancer might be a major asset in the fight against this disease, and could allow TIP60 to be used as a biomarker or therapeutic target for breast cancer progression in the future.

International audience; In the context of emerging biorefinery for microalgae, polyethyleneimine (PEI), has been tested in order to achieve separation of fat-soluble and water-soluble compounds from Haematococcus pluvialis. Several parameters were taken into account (ratio between sample and PEI, pH, and ionic strength) and 2 conditions (0.075% PEI pH 7.4, and 0.100% PEI pH8.5) were studied for up-scalability, with a recovery of flocculated compounds (lipids and pigments), and a complete characterization of both phases. Using 0.075% PEI, pH7.4, 100% sugars and 89.8% proteins were retained in the supernatant, but some trace of beta-carotene were also detected. For 0.100% PEI, pH 8.5, a loss in proteins content was highlighted (61.2% proteins retained), but no residual lipids or pigments were detected. PEI could therefore be considered as an efficient method to fractionate fat-soluble and water-soluble compounds from microalgae.

Aim: Here, we investigated how the St Gallen breast molecular subtypes displayed distinct histone H3 profiles. Patients & methods: 192 breast tumors divided into five St Gallen molecular subtypes (luminal A, luminal B HER2-, luminal B HER2+, HER2+ and basal-like) were evaluated for their histone H3 modifications on gene promoters. Results: ANOVA analysis allowed to identify specific H3 signatures according to three groups of genes: hormonal receptor genes (ERS1, ERS2, PGR), genes modifying histones (EZH2, P300, SRC3) and tumor suppressor gene (BRCA1). A similar profile inside high-risk cancers (luminal B [HER2+], HER2+ and basal-like) compared with low-risk cancers including luminal A and luminal B (HER2-) were demonstrated. Conclusion: The H3 modifications might contribute to clarify the differences between breast cancer subtypes.

To ensure continuous innovations, food industries need tools which enable to predict physical-properties of food during a change of process or recipe. In this work, a thermodynamic model is suggested to predict pH and water activity of pork meat in presence of different additives such as salts or organic acids used in food industry. The predictions of pH and aw are satisfactory in a wide prediction domain, with a good accuracy. In add, a neural network mimetic of thermodynamic model is developed in order to facilitate the use of thermodynamic model and reduce calculation time.

Salmonella and Listeria monocytogenes are two pathogenic bacteria that most frequently contaminate pork meat. In dry fermented sausages, several hurdles are used for controlling bacterial growth such as nitrite and salt addition. In Europe, practices consist of adding potassium nitrate (250ppm expressed as NaNO3) or a combination of nitrate/nitrite (150/150ppm expressed as NaNO3/NaNO2 respectively). However, involvement of these additives in nitrosamine formation is a matter of concern. Consequently, a decrease in nitrite/nitrate amounts is proposed. The aim of this study was to evaluate the impact of reducing levels of these additives on Listeria and Salmonella behavior. Using challenge-tests, five trials were carried out by varying the concentration of nitrate and nitrate/nitrite. Results shown that nitrite is a relevant hurdle for control Salmonella and Listeria. At the end of drying, the most significant reductions of pathogens are obtained in sausages with nitrite added at the both tested concentrations (120 or 80ppm NaNO2).

Breast cancer is a heterogeneous disease due to its clinico-pathological features and response to therapy. The classification of breast tumors based on their hormone receptor status and pathologic features. Post-translational histone modifications come into prominence for regulation of gene expression in cancer pathogenesis. Here, we analyzed dysregulation of H3K9ac and H3K27me3-enriched subtype-specific genes using ChIP-on-chip assay in breast cancer tumors and matched normal tissue samples. Breast cancer tumors were classified according to St Gallen Consensus 2013. Our results indicated that the promoter regions of genes modified by H3K9ac epi-mark are commonly associated with tumors with HER2-positive and TNBC subtype. H3K27me3-enriched genes were comprised of Luminal A and B1 subtypes. We constructed a network structure to elicit epigenetically regulated genes related with breast cancer progression. The central genes of the network (RUNX1, PAX3, GATA4 and DLX5) were subjected for epigenetically dysregulation in association with different breast cancer subtypes. Our study submits epigenetic mechanisms are crucial to elicit subtype-specific regulation in breast cancer and ChIP-on-chip assay provides a better understanding for breast tumorigenesis and new approaches for prevention and treatment.

In food and biological processes, aqueous complexes cover a wide diversity of species and the presence of several phases. The modelling of such processes must take into account these specificities, which require a generalization of the existing thermodynamic models of aqueous solutions. The chemical potential (the molar Gibbs free energy) of a given compound is an important variable to characterize the physical-chemical properties at equilibrium. Its value depends on two parameters: the Gibbs free energy of formation and the activity coefficient. Both are linked to a chosen reference state. Then, the main thermodynamic modelling task consists in the prediction and/or the collection of formation properties data and in the development of a predictive model of activity coefficients. In this study, a method of prediction of the gas phase formation properties of several organic molecules of interest in foods and biological media using the same input data as those of the COSMO-RS model (i.e., results of quantum DFT/COSMO calculations) is introduced. This kind of fully predictive approach allows the treatment of conformations. This is its main advantage compared to classical group contribution methods. For fifteen of the studied molecules, the Gibbs free energies of formation predicted at infinite dilution in water are also calculated and compared to experimental data.

International audience; An epoxy-activated monolithic Convective Interaction Media (CIM®) disk was used for the immobilization of endodextranase D8144 from Penicillium sp. (EC 3.2.1.11) in order to produce on-line isomalto-oligosaccharides (IMOs) from Dextran T40. Enzymatic parameters, molecular weight of IMOs and performance of the IMmobilized Enzymes Reactor (IMER) were investigated. The immobilization yield of enzymes was about 45.3% (w/w), and the real specific activity close to 3.26 U mg−1. The Km values did not significantly change between free (12.8 g L−1) and immobilized enzymes (14.2 g L−1), due to the absence of diffusional limitation. The IMER system presented more than 80% of its residual activity after 5000 column volumes, highlighting the high stability of the immobilized endodextranases. Response surface methodology was used to enhance the performance of the IMER. Depending on dextran concentrations and flow rates, specific patterns of IMOs distributions were observed during the enzymatic hydrolysis. Finally, prebiotic activity was also investigated on IMOs produced by medium conditions (flow rate 0.3 mL min−1 and dextran concentrations 4% w/w) against Lactobacillus rhamnosus GG (ATCC 53103). Their scores were at least as good as two commercialized fructo-oligosaccharides (FOS), Fibrulose® F97 and Orafti® P95.

This chapter aims at developing the idea that all components of numerical simulators are currently available for establishing a comprehensive understanding of meat products, rather than describing different fermented meat products, various processes, or evolution of qualities (taste, color, aroma, texture, microbiology). Two examples are described: the first concerns the prediction of the growth or no growth of bacteria at the surface of meat; the second is a three-dimensional ham model conceived to understand the dry-cured ham process. In the two cases, the approaches are similar and consist in aggregating heat and mass transfer models and (micro) biological models.

International audience; This study has for objective the determination of thermal, mechanical and acoustical properties of insulating bio-based composite made with chitosan and sunflower's stalks particles. An experimental design was established to find the size grading of particles, the ratio chitosan/sunflower particles and the stress of compaction influencing the thermal and mechanical properties. Composites with a thermal conductivity $(\kappa)$ of 0.056 W/m/K, a maximum stress $(\sigma_{\text{max}})$ of 2 MPa and an acoustic coefficient of absorption $(\alpha)$ of 0.2 were obtained with a ratio of chitosan of 4.3% (w/w) and a size grading of particles higher to 3 mm. These mechanical and thermal performances are competitive with those of other insulating bio-based materials available on the market.

A biorefinery is a facility that integrates biomass conversion processes and equipment to produce fuels, power and chemicals from biomass. This concept is applied here to hydrogen production by anaerobic fermentation. Its biological production is increasingly perceived as a potential pathway for developing renewable sources of energy, due to hydrogen's high energy content (142 kJ g−1) and the absence of harmful emissions during utilization in a hydrogen fuel cell. The main secondary metabolites produced during dark fermentation (volatile fatty acids, VFAs) are building blocks and can also serve as an alternate carbon source for lipid production from oleaginous yeast strains for biodiesel production.The concept proposed here is the coupling of two main compartments. In the first one, lignocellulosic biomass is transformed by dark fermentation into hydrogen and VFAs. The medium used in the first compartment is transferred via an immersed membrane bioreactor to the second compartment where the produc...

Recently, we have introduced the COSMO-RS-PDHS model, i.e. a new tool to predict activities and activity coefficients of electrolytes in binary {water-electrolyte} systems. However, the fixed hydration assumption used in this early stage of the development of model, limits its range of validity (from 0 to 6 molal). The present study aims at overcoming this limitation through the development of a new chemical model that handles the successive hydration reactions of the chemical species. Using the COSMO-RS values of chemical potentials of hydrated species, the equilibrium constants of these successive hydration reactions are predicted. The resulting model accurately predicts water activities and activity coefficients of electrolytes in concentrated solutions (up to 20 molal). COSMO-RS-PDHS is finally used to predict water activities in several {water-polyol} systems. The predicted activity coefficients and water activity results are in very good agreement with experimental data, even by using the default COSMO-radii (if available like in {water-LiCl}, {water-NaCl} or {water-polyol} solutions), as well as by using our proposed set of COSMO-radii which enables to predict activity coefficients in the {water-KCl} mixture where the potassium is not yet included in the parameterized set of COSMO-radii in the current state of art of COSMO-RS.

This study focuses on the use of acetic acid as carbon source for cell mass and lipid production using an oleaginous yeast, Cryptococcus curvatus. To improve this cell mass and lipid production on acetic acid, a numerical model was built to predict the yeast behavior. The model was first calibrated and validated on a fed-batch culture of the oleaginous yeast grown on acetic acid. After the validation step, this model was used as a predictive tool to search for optimal dilution rate and C/N ratios for continuous culture. A continuous culture was then launched using these culture parameters, revealing that the experimental data fitted the model predictions. At steady-state, cell mass concentration was stabilized at 26.7 g/L containing 48–53% of lipid content. A maximal lipid productivity of 0.54 g L−1 h−1 was obtained, which was superior to those reported in literature. This model could be qualified as a mechanistic one since it allows understanding reactions underlying the lipid production process. The experimental data fitted the model predictions, which confirmed that the use of a model is a powerful and predictive tool which could help the operator to process parameters to improve the culture.

International audience

Numerous studies have shown that breast cancer and epigenetic mechanisms have a very powerful interactive relation. The MCF7 cell line, representative of luminal subtype and the MDA-MB 231 cell line representative of mesenchymal-like subtype were treated respectively with a Histone Methyl Transferase Inhibitors (HMTi), 3-Deazaneplanocin hydrochloride (DZNep), two histone deacetylase inhibitors (HDACi), sodium butyrate (NaBu), and suberoylanilide hydroxamic acid (SAHA) for 48 h.Chromatin immunoprecipitation (ChIP) was used to observe HDACis (SAHA and NaBu) and HMTi (DZNep) impact on histones and more specifically on H3K27me3, H3K9ac and H3K4ac marks with Q-PCR analysis of BRCA1, SRC3 and P300 genes. Furthermore, the HDACi and HMTi effects on mRNA and protein expression of BRCA1, SRC3 and P300 genes were checked. In addition, statistical analyses were used.In the MCF7 luminal subtype with positive ER, H3k4ac was significantly increased on BRCA1 with SAHA. On the contrary, in the MDA-MB 231 breast cancer cell line, representative of mesenchymal-like subtype with negative estrogen receptor, HDACis had no effect. Also, DZNEP decreased significantly H3K27me3 on BRCA1 in MDA-MB 231. Besides, on SRC3, a significant increase for H3K4ac was obtained in MCF7 treated with SAHA. And DZNEP had no effect in MCF7. Also, in MDA-MB 231 treated with DZNEP, H3K27me3 significantly decreased on SRC3 while H3K4ac was significantly increased in MDA-MB-231 treated with SAHA or NaBu for P300.Luminal and mesenchymal-like breast cancer subtype cell lines seemed to act differently to HDACis (SAHA and NaBu) or HMTi (DZNEP) treatments.

The improvement of culture parameters for lipid production from acetate as carbon source was investigated using the oleaginous yeast Cryptococcus curvatus. A new pH regulation system dispensing acetate was developed for fed-batch culture and allowed obtaining nearly 80 g/L biomass within 60 h with a maximal growth rate of 0.28 h(-1). A biological model was developed from experimental data. The influence of three C/N ratios of 300, 500 and 900 were tested during a multi-phases process on lipid accumulation. The C/N ratio of 300 was reported to be the most suitable for lipid storage. No significant increase of lipids content was obtained with higher value. A maximal content of 60% DCW of lipid was obtained. The determination of fatty acids profiles of the microbial oils has confirmed that the valorization of acetate by microbial oils production was a promising perspective.

In prostate cancer, DNA methylation is significantly associated with tumor initiation, progression, and metastasis. Previous studies have suggested that soy phytoestrogens might regulate DNA methylation at individual candidate gene loci and that they play a crucial role as potential therapeutic agents for prostate cancer. The purpose of our study was to examine the modulation effects of phytoestrogens on a genome-wide scale in regards to DNA methylation in prostate cancer. Prostate cancer cell lines DU-145 and LNCaP were treated with 40 mu M of genistein and 110 mu M of daidzein. DNMT inhibitor 5-azacytidine (2 mu M) and the methylating agent budesonide (2 mu M) were used to compare their demethylation/methylation effects with phytoestrogens. The regulatory effects of phytoestrogens on DNA methylation were analyzed by using a methyl-DNA immunoprecipitation method coupled with Human DNA Methylation Microarrays (MeDIP-chip). We observed that the methylation profiles of 58 genes were altered by genistein and daidzein treatments in DU-145 and LNCaP prostate cancer cells. In addition, the methylation frequencies of the MAD1L1, TRAF7, KDM4B, and hTERT genes were remarkably modified by genistein treatment. Our results suggest that the modulation effects of phytoestrogens on DNA methylation essentially lead to inhibition of cell growth and induction of apoptosis. Genome-wide methylation profiling reported here suggests that epigenetic regulation mechanisms and, by extension, epigenetics-driven novel therapeutic candidates warrant further consideration in future "omics" studies of prostate cancer.

In food and biological processes, aqueous complexes cover a wide diversity of species and the presence of several phases. The modelling of such processes must take into account these specificities, which require a generalization of the existing thermodynamic models of aqueous solutions. The chemical potential (the molar Gibbs free energy) of a given compound is an important variable to characterize the physical-chemical properties at equilibrium. Its value depends on two parameters: the Gibbs free energy of formation and the activity coefficient. Both are linked to a chosen reference state. Then, the main thermodynamic modelling task consists in the prediction and/or the collection of formation properties data and in the development of a predictive model of activity coefficients. This work introduces a new prediction tool of activity coefficients of electrolytes in {water-salt} systems. This tool is based on an extension of the COSMO-RS method towards the representation of the thermodynamic equilibrium properties of charged species. For this purpose, the long-range interactions between ions are taken in account by a Pitzer-Debye-Huckel term. The resulting model called “COSMO-RS-PDHS” is then fully predictive.

Simulation processes and their optimization require knowledge of the physical-chemical properties of the pure substances and the mixtures being implemented. This constitutes the field of study of applied thermodynamics that allows, from the molecular representation of pure substances and mixtures, the prediction of the physical-chemical properties while ensuring consistency with experimental data.

Numerical simulation is a study method that consists of analyzing a phenomenon, a process or the behavior of a system through a model. While modeling consists of implementing the model, simulation makes use of the model that shows a behavior similar to the real system in order to consider a very large number of scenarios whose synthesis subsequently allows decision-making. During the design of new products, simulation must be regarded as an experiment, the term “software experiment” is sometimes used, that is as a tool for exploring possibilities. The use of computers facilitates the multiplication of studies, the enrichment of the cases studied and sometimes the correct break down of the factors having strong interactions between them.

International audience; Temperature, salt and water contents are key processing factors in dry-cured ham production. They affect how proteolysis, lipid oxidation, structure and texture evolve, and thus determine the sensory properties and final quality of dry-cured ham. The aim of this study was to quantify the interrelationships and the time course of (i) proteolysis, (ii) lipid oxidation, (iii) five textural parameters: hardness, fragility, cohesiveness, springiness and adhesiveness and (iv) four structural parameters: fibre numbers, extracellular spaces, cross section area, and connective tissue area, during the dry-cured ham process. Applying multiple polynomial regression enabled us to build phenomenological models relating proteolysis, salt and water contents to certain textural and structural parameters investigated. A linear relationship between lipid oxidation and proteolysis was also established. All of these models and relationships, once combined with salt penetration, water migration and heat transfer models, can be used to dynamically simulate all of these phenomena throughout dry-cured ham manufacturing.

Since the beginning of physical chemistry, tens of thousands of articles have been written in order to understand the behavior of fluid mixtures. Although there is no general theory on the properties of fluid mixtures, a large number of theories and models whose area of application is restricted to a particular type of mixture are available. The Gibbs free energy is a function of the mole fractions of the different constituents of the mixture. A first approach consists therefore of writing a limited expansion of this function and, according to the order of the expansion, the Margules, Redlich-Kister or Van Laar equations appear. However, although series expansion is very flexible, (1) it does not explain physical and chemical phenomena occurring in a mixture and (2) it has mainly no predictive power since the phase transition of binary mixtures to ternary mixtures requires the adjustment of additional parameters.

This work introduces a new tool able to predict water activities and activity coefficients of electrolytes in binary {water–electrolyte} systems. In mixtures containing electrolytes, the system is characterized by the presence of both molecular and ionic species, resulting in three different types of interactions: ion–ion, molecule–molecule and ion–molecule. Ion–ion interactions are governed by electrostatic forces between ions that have a much longer range than other intermolecular forces. The long range interactions between ions are taken in account by the Pitzer term based on the Debye–Huckel theory. Molecule–molecule and ion–molecule interaction forces are known to be short-range in nature. To determine short range mean activity coefficients of salts in {water–electrolyte} binary mixtures, a chemical treatment of ions solvation is combined with the predictive power of the COSMO-RS model. The main originality of this work resides in this chemical treatment model that provides the thermodynamic relations which enable to determine the equilibrium properties of the real solution {water–salt}, knowing those of a hypothetical mixture containing water and hydrated clusters. The resulting model called “COSMO-RS-PDHS” predicts results that are in good agreement with experimental data.

Background It is well established that genetic and epigenetic alterations are common events in prostate cancer, which may lead to aberrant expression of critical genes. The importance of epigenetic mechanisms in prostate cancer carcinogenesis is increasingly evident. In this study, the focus will be on histone modifications and the primary objectives are to map H3K27me3 marks and quantify RAR beta 2, ER alpha, SRC3, RGMA, PGR, and EZH2 gene expressions in prostate cancer tissues compared to normal tissues. In addition, a data analysis was made in connection with the clinicopathological parameters. Methods 71 normal specimens and 66 cancer prostate tissues were randomly selected in order to assess the proportion of the repressive H3K27me3 mark and gene expression. H3K27me3 level was evaluated by ChIP-qPCR and mRNA expression using RT-qPCR between prostate cancer and normal tissues. Subsequently, western-blotting was performed for protein detection. The analysis of variance (ANOVA) was performed, and Tukey’s test was used to correct for multiple comparisons (p-value threshold of 0.05). The principal component analysis (PCA) and discriminant factorial analysis (DFA) were used to explore the association between H3K27me3 level and clinicopathological parameters. Results The study demonstrated that H3K27me3 level was significantly enriched at the RAR beta 2, ER alpha, PGR, and RGMA promoter regions in prostate cancer tissues compared to normal tissues. After stratification by clinicopathological parameters, the H3K27me3 level was positively correlated with Gleason score, PSA levels and clinical stages for RAR beta 2, ER alpha, PGR, and RGMA. High H3K27me3 mark was significantly associated with decreased RAR beta 2, ER alpha, PGR and RGMA gene expressions in prostate cancer sample compared to the normal one. Moreover, the results showed that mRNA level of EZH2, AR and SRC3 are upregulated in prostate cancer compared to normal prostate tissues and this correlates positively with Gleason score, PSA levels and clinical stages. Obviously, these observations were confirmed by protein level using western-blot. Conclusions This data clearly demonstrated that H3K27me3 level correlated with aggressive tumor features. Also this study revealed that reverse correlation of RAR beta 2, ER alpha, PGR, and RGMA expressions with EZH2, SRC3, and AR expressions in prostate cancer tissues suggests that these genes are the target of EZH2. Therefore, all therapeutic strategies leading to histone demethylation with epigenetic drugs such as histone methyltransferase inhibitor may be relevant treatments against prostate cancer.

International audience; New beef products from low value cuts could be developed using marinating since this process has been shown to improve meat sensorial properties and shelf life. However, to optimise the process mathematical models are needed to predict evolution of the physicochemical properties that determine biochemical and structural changes. Two major works have been carried out to elaborate comprehensive models: (1) Thermodynamic models were adapted to predict water sorption isotherms and pH of beef meat tissue in presence of salts (NaCl, KCl) and organic acids (acetic, lactic, citric and ascorbic acid), (2) Fickian numerical models were set up to predict the migration of ions within meat cuts using apparent diffusivities previously estimated from 1D experiments. Simulation calculations showed reasonable agreement with measurements and can be used to investigate the effect of marinating conditions, product heterogeneity, dimension and shape

International audience

International audience; Throughout dry-cured ham production, salt and water content, pH and temperature are key factors affecting proteolysis, one of the main biochemical processes influencing sensory properties and final quality of the product. The aim of this study was to quantify the effect of these variables (except pH) on the time course of proteolysis in laboratory-prepared pork meat samples. Based on a Doehlert design, samples of five different types of pork muscle were prepared, salted, dried and placed at different temperatures, and sampled at different times for quantification of proteolysis. Statistical analysis of the experimental results showed that the proteolysis index (PI) was correlated positively with temperature and water content, but negatively with salt content. Applying response surface methodology and multiple linear regressions enabled us to build phenomenological models relating PI to water and salt content, and to temperature. These models could then be integrated into a 3D numerical ham model, coupling salt and water transfers to proteolysis

International audience; Liquid-phase pKa values play a key role in food science. Chemical properties of molecules depend largely on whether they are ionized or not. Most organic molecules are capable of gaining and/or losing a proton in aqueous solutions. Proton transfer most. frequently occurs between water and any ionizable atom of the organic molecule. The molecule’s response to profanation or deprotonation depends significantly on the site that was disturbed by proton transfer. Partial charge distribution in the molecule also varies with protonation of the acidlbase active sites. Then it can he used to determine the pKa of a molecule.First, we use the COSMO-RS method, a combination of the quantum chemical dielectric continuum solvation model COSMO with a statistical thermodynamics treatment fin- more Realistic Solvation (RS) simulations, for the direct prediction of pKa constants of about 50 molecules (amino-acids, dipeptides and tripeptides). Then, we compare our results with experimental data and the pKa values predicted using two other methods. We used respectively the ChemAxon method using a program based on the calculation of partial charge of atoms in the molecule and the ACD/Labs method that enables to calculate single pKa values. for all possible dissociation centers when the rest of the molecule is considered neutral, using an internal database containing chemical structures and their experimental pKa values.The averaged Root Mean Square Error (RMSE) of the predicted pKa values for each method compared to experimental results were respectively 0.596 for COSMO-RS, 0.445 for ChemAxon and 0.490 for ACD/Labs. While ACDILabs and ChemAxon are parameterized using a large set ofexperimental data (including several of the studied molecules), the COSMO- RS method was used in a fully predictive way. Regarding these results, COSMO-RS appears as a promising method to predict the pKa values of molecules of interest in food science with scarce available pKa values such as peptides. The final goal of this study is to use the pKa values in a predictive thermodynamics model for products of interest in food industry. For this purpose, the effects of several factors (like conformations set treatment in COSMO-RS calculations, ionic strength effect) that can affect the comparison between observed and predicted pKa data are discussed.; Les valeurs de constantes d’acidité (pKa) jouent un rôle très important, en particulier dans l’industrie alimentaire. Les propriétés chimiques des molécules dépendent significativement de leurs états d’ionisation. La plupart des molécules sont capables de gagner et/ou perdre un proton dans les solutions aqueuses. Ce transfert de proton apparaît la plupart du temps entre l’eau et un atome ionisable de la molécule organique. La réponse de la molécule à la protonation ou à la déprotonation dépend significativement du site concerné par le transfert de proton. La distribution partielle des charges dans la molécule varie également en fonction des sites actifs pour la protonation du couple acide; base. Par conséquent on peut l’utiliser pour déterminer le pKa d’une molécule.Dans un premier temps, nous avons utilisé la méthode COSMO-RS, une combinaison du modèle de solvatation diélectrique (COSMO) et d’un traitement de thermodynamique statistique pour des solvants plus réels (RS), pour prédire les constantes de dissociation de 50 molécules environ (des acides aminés, des dipeptides et des tripeptides). Les résultats de pKa obtenus ont été comparés aux valeurs expérimentales, ainsi qu’aux valeurs de pKa prédites par deux autres méthodes. Nous avons utilisé respectivement la méthode ChemAxon, utilisant un programme basé sur le calcul des charges partielles des atomes d’une molécule, et la méthode ACD/Labs qui permet de déterminer des valeurs de pKa pour chaque centre de dissociation en considérant que le reste de la molécule est neutre, en utilisant une base de données internes contenant des structures chimiques ainsi que leurs valeurs expérimentales de pKa.L’écart-type moyen des valeurs prédites vaut respectivement 0,596 pour la méthode COSMO-RS, 0,445 pour la méthode ChemAxon et 0,490 pour la méthode ACD/Labs. Au vu de ces résultats, la méthode COSMO-RS apparaît comme une méthode prometteuse pour prédire les valeurs de pKa de molécules d’intérêt dans l’industrie alimentaire pour lesquelles peu de données de pKa sont disponibles comme les peptides, d’autant plus que les méthodes ACD/Labs et ChemAxon ont été paramétrées en utilisant un grand nombre de données expérimentales (incluant certaines des molécules étudiées dans cet article) alors que la méthode COSMO-RS a été utilisée d’un point de vue purement prédictif.L’objectif final de cette étude est d’utiliser ces valeurs de pKa dans un modèle thermodynamique prédictif pour des produits d’intérêt dans l’industrie alimentaire. Pour ce faire, les effets de certains facteurs (comme le traitement des conformations dans les calculs COSMO-RS,l’infuence de la force ionique) pouvant influencer la comparaison entre les données expérimentales et les données prédites, seront discutés.

International audience

2. ed. Mention d'édition : 2. ed.; International audience

Methyl ketones are detected in dry fermented sausages in which they contribute to the cured aroma. They have been associated with the inoculation of Staphylococcus carnosus used as starter culture. To evaluate the ability of bacterial starters to produce methyl ketones it was necessary to develop a rapid method. The method consists of a reaction catalyzed by a commercial NADPH-dependent alcohol dehydrogenase that reduces the 2-pentanone to its secondary alcohol. The linearity, the specificity, and the robustness were studied. Its accuracy was confirmed by comparison with the gas chromatography technique. Finally, the method was validated on biological samples such as the 2-pentanone produced by Staphylococcus camosus. The enzymatic method offers some advantages over the gas chromatography, as it is faster, simpler, and inexpensive; guaranteeing an effective way to assess bacterial ketone production. Fil: Fadda, Silvina G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Institut National de la Recherche Agronomique; Francia Fil: Lebert, André. Institut National de la Recherche Agronomique; Francia Fil: Talon, Régine. Institut National de la Recherche Agronomique; Francia

Breast cancer is responsible of cancer mortality in women worldwide. The challenge in carcinogenesis is to predict tumor progression. Epigenetics open new perspectives in this field. It was demonstrated that epigenetic alterations are involved in cancer. DNA methylation or histone modifications can regulate gene transcription. Our goal was to determine the role of different histone marks, such as H3K27me3, H3K4ac and H3K9ac on the expression of a panel of genes involved in breast cancer: BRCA1, ERβ, EZH2, P300, SRC3, ERα and PGR. For this study, we used less than one hundred sporadic breast tumors and matched normal tissues. We performed chromatin immunoprecipitation and Q-PCR. After that, we checked the gene expression assaying RNA with RT-QPCR and proteins with Western blotting. Finally, we demonstrated that H3K4ac marks behaved like H3K27me3 repressive marks. The increase of H3K9ac marks resulted in the overexpression of ERα and P300 genes in the tumors. For the underexpressed genes BRCA1 and ERβ, we found that their repression did not pass through the repressive marks H3K27me3 nor H3K4ac but by other mechanisms perhaps DNA methylation. Then, we used variance analysis and studied interactions between the studied different marks and intrinsic subtypes of breast cancer according to St Gallen International Expert Consensus. Finally, we defined gene-mark couples in each subtypes. At the end, a decision tree was drawn and determined 4 genes (BRCA1, ERα, ERβ, and PGR) and 2 marks (H3K27me3 and H3K4ac) that separated subtypes in the present study. Citation Format: Dominique J. Gallon-Bernard, Gaëlle Judes, Aslihan Dagdemir, Maureen Echegut, Seher Karsli-Ceppioglu, Marjolaine Ngollo, Andre Lebert, Frederique Penault-Llorca, Yves-Jean Bignon. Histone lysine trimethylation or acetylation in sporadic breast tumor and matched normal tissue. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1371. doi:10.1158/1538-7445.AM2014-1371

International audience

International audience

National audience

Various faciès of the lithological succession which represents the Cenomanian stage in its type area are discussed in their paleogeographical setting on the armorican border of the Paris Basin. The distribution of ammonite faunas is given with proposals for limits and subdivisions of the stage. Stratigraphi-cal correlations with Haute-Normandie are outlined and a possible supplementary reference section is suggested in the cliffs of the Pays de Caux., La succession lithologique constituant le Cénomanien dans la région-type présente des faciès variés qui sont replacés dans le cadre paléogéographique de la bordure armoricaine du Bassin de Paris. La répartition des faunes d'ammonites est précisée et les limites et divisions de l'étage sont proposées. Les corrélations stratigraphiques avec la Haute-Normandie sont rappelées et une coupe parastratotypique est proposée dans les falaises du Pays de Caux., Juignet Pierre, Kennedy William James, Lebert André. Le Cénomanien du Maine : formations sédimentaires et faunes d'Ammonites du stratotype. In: Géologie Méditerranéenne. Tome 5, numéro 1, 1978. Colloque sur le Cénomanien (France – Europe Occidentale), Paris, 6-7 septembre 1976. pp. 87-99.

An automated turbidimetric system, Bioscreen C, was used to monitor bacterial growth in microplates. The detection threshold and linear range of the instrument were determined. Bioscreen C was found to present certain problems in setting up temperature and O.D. stability. A systematic way to calculate growth parameters (maximal growth rate, lag time and logarithmic increase of population) was developed. The repeatability of growth was studied. The validity of the method was illustrated by studying the growth of 9 strains of Listeria monocytogenes under two conditions: 37°C, Aw 0.96, pH 7.0 and 10°C, Aw 1.00, pH 7.0. Growths in Bioscreen C were compared with growth obtained in a fermentor.

International audience

The purpose of this thesis was (1) to develop a new method for measuring the redox potentialas an indicator of color changes in fresh beef, (2) to model the impact of the factors influencing these changes and (3) to develop a tool to predict these changes. Meat juice has been shown to be a good mimetic medium for the study of color changes. Color change is faster in the juice than in the meat and faster at 20 °C than at 4 °C. Redox potential allows following color changes and a symmetry has been highlighted between this thermodynamic measure and color changes. Two color changes were observed, one from bright red to yellow/brown and the other from yellow/brown to dark red. The presence of microorganisms only accelerates an existing reaction during the first color change while it is essential for obtaining the second color change. The population causing the first change would be dominated by Pseudomonas and/or Brochothrix while lactic bacteria would be responsible for the second one. A predictive model of color changes (a*) was developed using the Jones Nachtscheim experimental design and the Gompertz equation. Non-linear optimization has shown that partial pressure of oxygen is the predominant factor in the regression (> 80%) before the storage temperature, the time of maturation under vacuum and the cutting angle of the meat., Cette thèse avait pour but de (1) développer une nouvelle méthode de mesure du potentiel d’oxydoréduction (pOR) comme indicateur des virements de couleurs dans la viande fraîche bovine, (2) modéliser l’impact des facteurs influençant ces virements et (3) développer un outil de prédiction de ces virements. Il a été mis en évidence que le jus de viande est un bon milieu mimétique de la viande pour l’étude des virements de couleur. Le virement de couleur est plus rapide dans le jus que dans la viande et plus rapide à 20 °C qu’à 4 °C. Le pOR permet de suivre les virements de couleur et une symétrie a été mis en évidence entre cette grandeur thermodynamique et les virements de couleur. Deux virements de couleur ont été observés, un de rouge vif à jaune/marron et l’autre de jaune/marron à rouge foncé. La présence de microorganismes ne fait qu’accélérer une réaction existante lors du premier changement de couleur alors qu’elle est essentielle pour l’obtention d’un second changement de couleur. La population causant le premier virement serait dominée par des Pseudomonas et/ou des Brochothrix alors que les bactéries lactiques seraient responsable du second. Un modèle de prédiction du virement de couleur (a*) a été développé à l’aide du plan d’expériences de Jones Nachtscheim et de l’équation de Gompertz. L’optimisation non linéaire a montré que la pression partielle en dioxygène est le facteur prédominant dans la régression (> 80 %) devant la température de stockage, le temps de maturation sous vide et l’angle de découpe de la viande.

A great part of the global production of energy vectors and chemicals comes from fossil fuels refinery. Because of the increase in oil price and their environmental impacts, the search for alternative, ecological and economic solutions is a current challenge. The replacement of oil with biomass as raw material for the production of fuels and chemicals is the driving force for the development of biorefinery complexes.This study is part of a project aiming at the biorefinery of lignocellulosic biomass for hydrogen and microbial lipids as biodiesel precursors. This work focuses on the biomass and lipids production step by the oleaginous yeast Cryptococcus curvatus using volatile fatty acids (VFAs) as carbon sources, which are synthesized during the anaerobic fermentation step. Yeast cultures have initially been realized using a model substrate, acetate, and fed-batch and continuous modes. The determination of the influence of different operating parameters on the biomass and lipids production led to the development of fed-batch cultures which kinetics, productivities and yields were competitive with those reported in the literature for cultures on simple substrates. A growth and lipid production model was built from these data to predict the behavior of the strain during continuous cultures and to obtain high lipid and biomass productivities. Finally, cultures were conducted using VFAs from anaerobic fermentation supernatant. The results confirmed the growth of these yeasts on this particular substrate and the production of lipids which composition was compatible with use as biodiesel., Une part importante de la production mondiale de vecteurs énergétiques et de produits chimiques provient de la raffinerie de combustibles fossiles. En raison de l'augmentation du prix du pétrole et de son impact environnemental, la recherche de solutions alternatives, écologiques et économiques constitue l’un des enjeux de notre siècle. Le remplacement du pétrole par de la biomasse en tant que matière première pour la production de carburants et de produits chimiques constitue la force motrice dans le développement de complexes de bioraffinerie.Cette étude fait partie d’un projet de bioraffinerie visant la valorisation de biomasse lignocellulosique par la production d’hydrogène et de lipides microbiens précurseurs de biodiesel. Ce travail se concentre en particulier sur l’étape de production de biomasse et de lipides par la levure oléagineuse Cryptococcus curvatus à partir d’acides gras volatils (AGVs) synthétisés au cours de la fermentation anaérobie productrice d’hydrogène. Les cultures ont dans un premier temps été réalisées à partir d’un substrat modèle, l’acétate, en fed-batch et en continu. La détermination de l’influence de différents paramètres opératoires sur la production de biomasse et de lipides à partir d’acétate a permis de mettre au point des cultures en fed-batch dont les cinétiques, les productivités et les rendements finaux étaient compétitifs avec ceux rapportés dans la littérature pour des cultures sur substrats simples. Un modèle de croissance et de production de lipides a été construit à partir de ces données afin de prédire le comportement de la souche lors de cultures continues, permettant d’obtenir des productivités en lipides et en biomasse élevées. Enfin, des cultures ont été menées à partir d’AGVs issus de surnageant de fermentation anaérobie. Les résultats ont confirmé la croissance de ces levures sur ce substrat particulier et la production de lipides dont la composition en acides gras estérifiés était compatible avec une utilisation comme biodiesel.