Search results for "membrana"
showing 10 items of 91 documents
Position paper - progress towards standards in integrated (aerobic) MBR modelling.
2020
Membrane bioreactor (MBR) models are useful tools for both design and management. The system complexity is high due to the involved number of processes which can be clustered in biological and physical ones. Literature studies are present and need to be harmonized in order to gain insights from the different studies and allow system optimization by applying a control. This position paper aims at defining the current state of the art of the main integrated MBR models reported in the literature. On the basis of a modelling review, a standardized terminology is proposed to facilitate the further development and comparison of integrated membrane fouling models for aerobic MBRs. ispartof: WATER …
Development of a polarimetric based optical biosensor using a free standing porous membrane
2013
The first published paper entitled Birefringent porous silicon membranes for optical sensing presents the results of the investigation on free standing silicon membranes prepared from p-type (110) surface oriented silicon as a material for optical biosensing. The birefringence and sensitivity of this type of porous membrane is theoretically simulated using the Bruggeman model which is extended to incorporate the influence that silicon oxidation has on both birefringence and sensitivity. Using this extended theoretical model a good agreement is found between the measured sensitivity values and the theoretical ones. The final section of this chapter describes the development of a statistical …
Caracterización proteómica de la interacción y la inserción de proteínas de membrana
2019
Las proteínas de membrana tienen funciones muy diversas en la célula, desde controlar el tráfico molecular hasta facilitar la transducción de señales. Sin embargo, el estudio de estas proteínas supone todo un reto por sus particulares características fisico-químicas. Su naturaleza hidrofóbica requiere un elevado control durante su síntesis. Uno de los pasos críticos en esta síntesis es la inserción en la bicapa lipídica. Generalmente, este proceso se produce a través de un mecanismo (co-traduccional) acoplado al proceso de traducción. Esta vía co-traduccional ha sido ampliamente estudiada y la maquinaria implicada en el proceso se conoce con bastante profundidad. Sin embargo, algunas proteí…
Membrane Insertion and Biogenesis of the Turnip Crinkle Virus p9 Movement Protein
2010
ABSTRACT Plant viral infection and spread depends on the successful introduction of a virus into a cell of a compatible host, followed by replication and cell-to-cell transport. The movement proteins (MPs) p8 and p9 of Turnip crinkle virus are required for cell-to-cell movement of the virus. We have examined the membrane association of p9 and found that it is an integral membrane protein with a defined topology in the endoplasmic reticulum (ER) membrane. Furthermore, we have used a site-specific photo-cross-linking strategy to study the membrane integration of the protein at the initial stages of its biosynthetic process. This process is cotranslational and proceeds through the signal recog…
Sec61alpha and TRAM are Sequentially Adjacent to a Nascent Viral Membrane Protein during its ER Integration
2007
Co-translational integration of a nascent viral membrane protein into the endoplasmic reticulum membrane takes place via the translocon. We have been studying the early stages of the integration of a double-spanning plant viral movement protein to gain insights into how viral membrane proteins are transferred from the hydrophilic interior of the translocon into the hydrophobic environment of the bilayer, where the transmembrane (TM) segments of the viral proteins can diffuse freely. Photocrosslinking experiments reveal that this integration involves the sequential passage of the TM segments past Sec61alpha and translocating chain-associating membrane protein (TRAM). Each TM segment is first…
Modification de la composition lipidique membranaire chez les bactéries lactiques en conditions de stress : étude du rôle physiologique des Acides Gr…
2010
The results obtained in this work have shown that in both lactic acid bacteria models, L. lactis subsp. cremoris and O. oeni, transcription of the cfa gene, encoding the Cfa synthase is stimulated when cells enter stationary phase of growth or when the cells are grown under stress conditions (acidic or presence of ethanol in the medium). The role of the CFAs has been apprehended by the comparative physiological analysis of the parental strain L. lactis subsp. cremoris and a Δcfa mutant generated in this strain. The high percentages of survival obtained in strains grown at pH 5.0 and undergoing acid stress (pH 3.0) prove that the cyclopropanation of unsaturated fatty acids is not essential t…
Functional exploration of the stress response in microorganisms of technological interest : dynamics of membrane response after an ethanol shock in S…
2015
The study of membrane response induced by ethanol stress in Saccharomyces cerevisiae aims to understand mechanisms involved in the survival of eukaryotic cells submitted to high ethanol concentrations. The cell membrane by its position between the intra- and extracellular environment is the first target of ethanolic perturbations. Experiments performed in this study aimed to characterize the maintain of the functional integrity of the membrane in relation to the sterol composition in the yeast S. cerevisiae submitted to different types of ethanolic disturbances: increasing concentrations of ethanol in the growth medium; ethanolic shocks of increasing magnitude; shock 20% ethanol for 15 minu…
Rôle de la Dynamique Membranaire dans la Mise en Place des Mécanismes de Défense chez le Tabac
2011
Cryptogein, a protein secreted by the oomycete Phytophthora cryptogea, induces defense mechanisms in tobacco. Several proteins involved in the associated signaling pathway were identified and localized on the plasma membrane (PM). A fraction resistant to solubilization by detergent named DIMs for Detergent Insoluble Membranes, enriched in sterols an sphigolipids had been isolated from tobacco PM. It was proved to contain proteins previously identified as actors of the signaling cascade triggered by cryptogein. In animal cells, the dynamic association of proteins to sterol and sphingolipid rich microdomains under the influence of a biological stimulus plays an essential role in the regulatio…
Les radeaux membranaires et la signalisation végétale
2016
Face à une fluctuation des paramètres de son milieu ambiant ou à une agression biotique, la cellule végétale met en place une réponse adaptative dont les étapes les plus précoces sont la reconnaissance précise et rapide du stress, capable d’induire le développement d’une cascade de signalisation appropriée. Certains des acteurs de ces voies sont localisés sur la membrane plasmique (MP). En fonction de l’espèce, l’état physiologique… d’une cellule, on trouve au sein de sa MP des lipides, des protéines et des oses de structures et en concentrations variables. Chez les cellules de tabac, par exemple, on compte environ 50 lipides pour une protéine.Bien que moins nombreuses, les protéines ont po…