37 research outputs found

    Tributyltin (TBT) biodegradation induces oxidative stress of Cunninghamella echinulata

    Get PDF
    Tributyltin (TBT) is one of the most deleterious compounds introduced into natural environment by humans. The ability of Cunninghamella echinulata to degrade tributyltin (TBT) (5 mg l-1) as well as the effect of the xenobiotic on fungal amino acids composition and proteins profile were examined. C. echinulata removed 91% of the initial biocide concentration and formed less hazardous compounds dibutyltin (DBT) and monobutyltin (MBT). Moreover, the fungus produced a hydroxylated metabolite (TBTOH), in which the hydroxyl group was bound directly to the tin atom. Proteomics analysis showed that in the presence of TBT, the abundances of 22 protein bands were changed and the unique overexpressions of peroxiredoxin and nuclease enzymes were observed. Determination of free amino acids showed significant changes in the amounts of 19 from 23 detected metabolites. A parallel increase in the level of selected amino acids such as betaine, alanine, aminoisobutyrate or proline and peroxiredoxin enzyme in TBT-containing cultures revealed that TBT induced oxidative stress in the examined fungus.National Science Centre, Poland (Project No. UMO-2014/13/N/NZ9/00878)

    Wormhole formation in dissolving fractures

    Full text link
    We investigate the dissolution of artificial fractures with three-dimensional, pore-scale numerical simulations. The fluid velocity in the fracture space was determined from a lattice-Boltzmann method, and a stochastic solver was used for the transport of dissolved species. Numerical simulations were used to study conditions under which long conduits (wormholes) form in an initially rough but spatially homogeneous fracture. The effects of flow rate, mineral dissolution rate and geometrical properties of the fracture were investigated, and the optimal conditions for wormhole formation determined.Comment: to be published in J. Geophys Re

    Simulation of chemical vapor infiltration and deposition based on 3D images: a local scale approach

    Get PDF
    International audienceA numerical solution for the simulation of chemical vapor infiltration of ceramic matrix composites is presented. This computational model requires a 3D representation of the preform. Gas transport and chemical reaction are simulated by a Monte Carlo random walk technique. The developed algorithm can also be used for determination of effective transport and reaction properties in a porous medium. It is firstly validated by considering the simple case of diffusion and reaction in a flat pore. Results of infiltration of an actual fiber arrangement are described and discussed. Extension to deposition on a thin substrate with asperities is also studied

    Mass Spectrometry-Based Metabolomics to Elucidate Functions in Marine Organisms and Ecosystems

    Get PDF
    Marine systems are very diverse and recognized as being sources of a wide range of biomolecules. This review provides an overview of metabolite profiling based on mass spectrometry (MS) approaches in marine organisms and their environments, focusing on recent advances in the field. We also point out some of the technical challenges that need to be overcome in order to increase applications of metabolomics in marine systems, including extraction of chemical compounds from different matrices and data management. Metabolites being important links between genotype and phenotype, we describe added value provided by integration of data from metabolite profiling with other layers of omics, as well as their importance for the development of systems biology approaches in marine systems to study several biological processes, and to analyze interactions between organisms within communities. The growing importance of MS-based metabolomics in chemical ecology studies in marine ecosystems is also illustrated

    Étude du mĂ©tabolisme du tributylĂ©tain par chromatographie liquide-spectromĂ©trie de masse

    Get PDF
    La contamination par le tributylĂ©tain (TBT) et les butylĂ©tains (BTs), en gĂ©nĂ©ral, est encore un sujet d'actualitĂ© en Ă©cotoxicologie aquatique. Ces composĂ©s chimiques ont une faible dĂ©gradabilitĂ© dans l'environnement, un taux d'accumulation gĂ©nĂ©ralement Ă©levĂ© et une toxicitĂ© Ă  long terme. La biotransformation des contaminants est un processus qui joue un rĂŽle important pour rĂ©duire la toxicitĂ© des composĂ©s en gĂ©nĂ©ral et pour leur excrĂ©tion hors de l'organisme. L'identification des produits et des voies mĂ©taboliques d'un contaminant est donc une Ă©tape importante pour comprendre ses mĂ©canismes de toxicitĂ©. L'objectif principal de ce travail Ă©tait d'examiner en dĂ©tail le mĂ©tabolisme in vivo et in vitro du TBT, en utilisant la chromatographie liquide haute performance couplĂ©e Ă  la spectromĂ©trie de masse par une interface d'ionisation Ă  pression atmosphĂ©rique (LC-API-MS"). L'avantage de cette technique d'ionisation douce est l'analyse de la structure des molĂ©cules polaires, peu volatiles ou thermiquement fragiles, difficilement observables par d'autres techniques analytiques (e.g. la GC-MS) . Dans un premier temps, nous avons dĂ©veloppĂ© une mĂ©thode d'analyse des BTs par LC-APCI-MS qui a servi par la suite Ă  la dĂ©tection des mĂ©tabolites du TBT gĂ©nĂ©rĂ©s in vitro et in vivo. Nous avons d'abord synthĂ©tisĂ© chimiquement un des dĂ©rivĂ©s mĂ©taboliques de phase 1 du TBT non disponible commercialement, le chlorure du delta-hydroxybutyl-dibutylĂ©tain (4-0HBuDBTCl), composĂ© plus polaire que le TBT. Nous avons dĂ©veloppĂ© des mĂ©thodes de sĂ©paration par gradient d'Ă©lution en phase inverse et de dĂ©tection simultanĂ©e des deux composĂ©s, ainsi que d'un dĂ©rivĂ© du TBT simplement dĂ©alkylĂ©, le dibutylĂ©tain (DBT). Les limites de dĂ©tection (LODs) de la mĂ©thode pour les deux composĂ©s (35 ng.mL-l pour le TBT et 26 ng.mL-l pour le 4-0HBuDBT) sont comparables aux valeurs publiĂ©es de LOD pour les BTs en LC-APIMS. Pour illustrer une application de notre mĂ©thode LC-MS, nous avons dĂ©veloppĂ© une mĂ©thode d'extraction Ă  partir d'Ă©chantillons d'eau de mer additionnĂ©s des deux composĂ©s de polaritĂ© diffĂ©rente, le TBT et le 4-0HBuDBT, en utilisant le n-hexane et l'acĂ©tate d'Ă©thyle. Cette mĂ©thode a permis la rĂ©cupĂ©ration en moyenne de 72 Ă  96 % des deux composĂ©s. En se basant sur les valeurs des limites de quantification (LOQ), notre mĂ©thode analytique LC-APCI-MS permet de mesurer approximativement 0,08-0,1 Ilg de chaque composĂ© dans 1 L d'eau de mer, ce qui est comparable aux mĂ©thodes publiĂ©es dans la littĂ©rature avec la mĂȘme technique analytique. Dans un deuxiĂšme temps, nous avons rĂ©alisĂ© des expĂ©rimentations in vitro Ă  l'aide de microsomes de foie d'un poisson salmonidĂ©, l'omble de fontaine Salvelinus fontinalis, et des expĂ©riences in vivo par exposition intrapĂ©ritonĂ©ale d'ombles de fontaine et par exposition via l'eau de mer de moules bleues Mytilus edulis. Le mĂ©tabolisme du TBT in vitro et in vivo par les deux organismes, l'omble de fontaine et la moule bleue, rĂ©vĂšle principalement des mĂ©tabolites hydroxylĂ©s de phase l du type OHBuDBT, qui sont considĂ©rĂ©s par certains auteurs comme une voie de dĂ©toxication. D'autres mĂ©tabolites avec la composition typique de l'Ă©tain, issus du mĂ©tabolisme in vivo, sont Ă©galement dĂ©tectĂ©s, mais leur caractĂ©risation n'a pas pu ĂȘtre rĂ©alisĂ©e Ă  cause de leur faible concentration et la faible quantitĂ© des extraits. Pour certains composĂ©s analysĂ©s en mode d'ionisation nĂ©gatif et dont les mlz > 500, on pourrait avancer qu'il s'agit de composĂ©s de phase II non identifiĂ©s. Dans un troisiĂšme temps, nous avons rĂ©alisĂ© des expĂ©rimentations in vitro et in vivo avec le 4-0HBuDBT. Les incubations in vitro de microsomes de foie d'ombles de fontaine avec ce composĂ© avait comme but de contourner l'Ă©tape du mĂ©tabolisme de phase l et tenter de gĂ©nĂ©rer un mĂ©tabolite conjuguĂ© de phase II Ă  l'acide glucuronique. Nos tentatives ont Ă©tĂ© infructueuses car le 4-0HBuDBT serait un faible substrat pour l'UDP-glucuronyl transfĂ©rase. Nous avons Ă©galement exposĂ© des ombles de fontaine par injection pĂ©ritonĂ©ale au 4-0HBuDBT, ainsi que des moules bleues via l'eau de mer au mĂȘme composĂ©, toujours dans le but de contourner le mĂ©tabolisme de phase l du TBT. Les rĂ©sultats obtenus rĂ©vĂšlent essentiellement la prĂ©sence d'un composĂ© avec le patron isotopique de l'Ă©tain Ă  mlz 321 en mode positif d'ionisation, aussi bien dans les extraits de foie de poissons que dans les extraits de tissus de moules. En nous basant sur une Ă©tude publiĂ©e et la communication personnelle avec un chercheur d'un autre laboratoire, nous avons suggĂ©rĂ© que ce composĂ© serait issu d'une hydroxylation supplĂ©mentaire du 4-0HBuDBT (mĂ©tabolisme de phase 1), pour gĂ©nĂ©rer un composĂ© carboxylĂ©, le carboxypropyl-dibutylĂ©tain (BU2Sn+(CH2)3COOH) . D'autres composĂ©s avec le patron isotopique typique de l'Ă©tain ont Ă©tĂ© dĂ©tectĂ©s dans les tissus des deux organismes, mais ils sont diffĂ©rents les uns des autres. La caractĂ©risation de ces composĂ©s n'a pas Ă©tĂ© possible, Ă  cause de leur faible concentration dans les extraits ainsi que la faible quantitĂ© de ces derniers. L'ensemble de ces travaux montre d'une part la capacitĂ© des organismes marins Ă  mĂ©taboliser le TBT et, d'autres part, la possibilitĂ© de dĂ©tecter des mĂ©tabolites principalement hydroxylĂ©s mĂȘme en trĂšs faibles quantitĂ©s, avec la technique LC-MS

    Impact of Diagenetic Alterations on the Petrophysical and Multiphase Flow Properties of Carbonate Rocks Using a Reactive Pore Network Modeling Approach

    No full text
    Sedimentary reservoir rocks generally have complex and heterogeneous pore networks that are related to the original depositional rock texture and subsequent diagenetic alterations. Such alterations are in part controlled by the original mineralogy and sedimentological facies, the compaction history, the involved fluids (and rock/fluid interactions), the flow history and the related physico-chemical conditions. During the diagenetic evolution (paragenesis), cycles of alternating dissolution (porosity enhancement) and precipitation (porosity destruction) caused by changes in chemical and thermodynamic conditions may lead to heterogeneous rock structure at both local and reservoir scale. In the absence of cored plugs to measure the petrophysical properties (i.e. porosity, permeability and formation factor) and multiphase flow properties (i.e. capillary pressure, relative permeability and resistivity index), a numerical tool that calculates these properties from pore structure data by predicting its evolution during the diagenetic cycle is of great interest for the petroleum industry and reservoir characterization studies. A Pore Network Model (PNM) provides opportunities to study transport phenomena in fundamental ways because detailed information is available at the pore scale. It has been used over the last decades to understand basic phenomena such as capillarity, multiphase flow or coupled phenomena. In particular, this modeling approach is appropriate to study the rock/fluid interactions since the mass exchange at surfaces can be modeled explicitly. It can provide quantitative information both on the effective transport property modifications due to the reactions and on the structure evolution resulting from dissolution/precipitation mechanisms. In the present paper, this approach is used to study the effect of the diagenetic cycle on the petrophysical properties of carbonate rocks. It involves three discrete steps. The first step consists of replacing the original complex pore structure of real porous media by a conceptual network. The second step consists of resolving the governing equations of the precipitation and dissolution phenomena (i.e. reactive convection diffusion equation) in the conceptual 3D pore network and deducing the local reactive fluxes and the motion of the fluid-solid interface. The third step consists of updating the new pore structure and calculating the new petrophysical properties of the modified porous media. Those steps are repeated in order to mimic a given diagenetic scenario. Finally, the multiphase flow properties of the current porous media are calculated. The impact of one diagenetic cycle of dissolution and precipitation on the pore networks’ heterogeneity and consequently on the petrophysical properties (i.e. porosity and permeability) and multiphase flow properties (i.e. relative permeability and capillary pressure) have been investigated. The permeability and porosity evolution during a given diagenetic cycle are calculated and analyzed as a function of the relevant dimensionless numbers (Peclet and Damköhler numbers) that characterize the flow and reaction regime. The correlation between these numbers and the dissolved/precipitated layer thickness distribution is investigated. This work contributes to improve the understanding of the impact of dissolution and precipitation on permeability and porosity modification. Using the PNM approach, multiphase flow properties and permeability-porosity relationship have been determined for different reactive flow regimes. These relationships are relevant input data to improve the quality of reservoir simulation predictions

    Quantification and Prediction of the 3D Pore Network Evolution in Carbonate Reservoir Rocks

    No full text
    This study presents an integrated approach that allows the reconstruction and prediction of 3D pore structure modifications and porosity/permeability development throughout carbonate diagenesis. Reactive Pore Network Models (PNM-R) can predict changes in the transport properties of porous media, resulting from dissolution/cementation phenomena. The validity and predictability of these models however depend on the representativeness of the equivalent pore networks used and on the equations and parameters used to model the diagenetic events. The developed approach is applied to a real case of a dolostone rock of the Middle East Arab Formation. Standard 2D microscopy shows that the main process affecting the reservoir quality is dolomitisation, followed by porosity enhancement due to dolomite dissolution and secondary porosity destruction by cementation of late diagenetic anhydrite. X-ray Ό-CT allows quantifying the 3D volume and distribution of the different sample constituents. Results are compared with lab measurements. Equivalent pore networks before dolomite dissolution and prior to late anhydrite precipitation are reconstructed and used to simulate the porosity, permeability characteristics at these diagenetic steps. Using these 3D pore structures, PNM-R can trace plausible porosity-permeability evolution paths between these steps. The flow conditions and reaction rates obtained by geochemical reaction path modeling can be used as reference to define PNM-R model parameters. The approach can be used in dynamic rock typing and the upscaling of petrophysical properties, necessary for reservoir modeling

    Quantification and Prediction of the 3D Pore Network Evolution in Carbonate Reservoir Rocks Quantification et prĂ©diction de l’évolution d’un rĂ©seau 3D de pores dans des roches rĂ©servoir de carbonates

    No full text
    This study presents an integrated approach that allows the reconstruction and prediction of 3D pore structure modifications and porosity/permeability development throughout carbonate diagenesis. Reactive Pore Network Models (PNM-R) can predict changes in the transport properties of porous media, resulting from dissolution/cementation phenomena. The validity and predictability of these models however depend on the representativeness of the equivalent pore networks used and on the equations and parameters used to model the diagenetic events. The developed approach is applied to a real case of a dolostone rock of the Middle East Arab Formation. Standard 2D microscopy shows that the main process affecting the reservoir quality is dolomitisation, followed by porosity enhancement due to dolomite dissolution and secondary porosity destruction by cementation of late diagenetic anhydrite. X-ray ÎŒ-CT allows quantifying the 3D volume and distribution of the different sample constituents. Results are compared with lab measurements. Equivalent pore networks before dolomite dissolution and prior to late anhydrite precipitation are reconstructed and used to simulate the porosity, permeability characteristics at these diagenetic steps. Using these 3D pore structures, PNM-R can trace plausible porosity-permeability evolution paths between these steps. The flow conditions and reaction rates obtained by geochemical reaction path modeling can be used as reference to define PNM-R model parameters. The approach can be used in dynamic rock typing and the upscaling of petrophysical properties, necessary for reservoir modeling. Cette Ă©tude prĂ©sente une approche intĂ©grĂ©e qui permet la reconstruction et la prĂ©diction des modifications de structure 3D de pores ainsi que le dĂ©veloppement de la porositĂ©/permĂ©abilitĂ© tout au long de la diagenĂšse des carbonates. Des modĂšles de rĂ©seau de pores rĂ©actifs peuvent prĂ©dire les changements en matiĂšre de propriĂ©tĂ©s de transport de milieux poreux, rĂ©sultant des phĂ©nomĂšnes de dissolution/cimentation. La validitĂ© et prĂ©dictibilitĂ© de ces modĂšles dĂ©pendent toutefois de la reprĂ©sentativitĂ© des rĂ©seaux de pores Ă©quivalents utilisĂ©s et des Ă©quations et paramĂštres utilisĂ©s pour modĂ©liser les Ă©vĂ©nements diagĂ©nĂ©tiques. L’approche dĂ©veloppĂ©e est appliquĂ©e au cas rĂ©el d’une roche dolomitique de la formation arabe moyen orientale. La microscopie 2D standard montre que le processus principal affectant la qualitĂ© de rĂ©servoir consiste en la dolomitisation, suivie d’un renforcement de la porositĂ© dĂ» Ă  une dissolution de la dolomie et Ă  une destruction de la porositĂ© secondaire par cimentation de l’anhydrite diagĂ©nĂ©tique tardive. La microtomographie par rayons X informatisĂ©e (X-rayÎŒ-CT; X-ray computer (micro)tomography) permet de quantifier le volume et la distribution en 3D des diffĂ©rents constituants d’échantillon. Les rĂ©sultats sont comparĂ©s avec les mesures de laboratoire. Des rĂ©seaux de pores Ă©quivalents avant la dissolution dolomitique et prĂ©alablement Ă  la prĂ©cipitation d’anhydrite tardive sont reconstruits et utilisĂ©s pour simuler les caractĂ©ristiques de porositĂ©, de permĂ©abilitĂ© lors de ces Ă©tapes diagĂ©nĂ©tiques. En utilisant ces structures 3D de pores, la PNM-R (Pore Network Modeling Reactive; modĂ©lisation rĂ©active de rĂ©seau de pores) peut suivre les voies d’évolution plausible de porositĂ©permĂ©abilitĂ© entre ces Ă©tapes. Les conditions d’écoulement et les vitesses de rĂ©action obtenues par modĂ©lisation des voies de rĂ©action gĂ©ochimiques peuvent ĂȘtre utilisĂ©es en tant que rĂ©fĂ©rence pour dĂ©finir les paramĂštres de modĂšle de PNM-R. L’approche peut ĂȘtre utilisĂ©e pour un typage dynamique de roches et le passage Ă  une Ă©chelle supĂ©rieure de propriĂ©tĂ©s pĂ©trophysiques, nĂ©cessaires pour la modĂ©lisation de rĂ©servoir
    corecore