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1.
Reverse enzyme synthesis in microemulsion-based organo-gels. 总被引:8,自引:0,他引:8
G D Rees M da Graca Nascimento T R Jenta B H Robinson 《Biochimica et biophysica acta》1991,1073(3):493-501
Lipase from three different sources has been immobilised in microemulsion-based gels (MBGs) with retention of catalytic activity. Such lipase-containing MBGs prove to be novel solid-phase catalysts for use in apolar organic solvents such as n-heptane. Using these systems, preparative-scale synthesis of a wide variety of esters under mild conditions was possible with products easily isolated and obtained in high yield. Stereoselective esterification of octan-2-ol was observed for all three lipases with Chromobacterium viscosum (CV) lipase yielding product with an enantiomeric excess of 92%. Repeated usage of a CV lipase-containing MBG resulted in a visually unchanged gel whose activity was 75% of the initial value after 30 days. The sectioned MBGs were well suited for use in column flow reactors and were also found to be effective esterification catalysts at temperatures as low as -20 degrees C. 相似文献
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Isabella V. Miller Graca Raposo Ulrich Welsch Olivia Prazeres da Costa Uwe Thiel Maria Lebar Martina Maurer Hans‐Ulrich Bender Irene von Luettichau Günther H. S. Richter Stefan Burdach Thomas G. P. Grunewald 《Biology of the cell / under the auspices of the European Cell Biology Organization》2013,105(7):289-303
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Anderson D Hughes JA Brinkworth MH Cebulska-Wasilewska A Nizankowska E Graca B Veidebaum T Peltonen K Sorsa M 《Mutation research》1999,445(2):167-173
Ras oncoproteins in blood plasma from workers exposed to petroleum emissions and unexposed controls were examined from Polish and Estonian samples. Twenty-four workers and 35 unexposed controls were examined from Poland and 97 exposed and 40 unexposed controls from Estonia. Of the Estonian workers, 50 were exposed to benzene in a benzene production plant and 47 to polyaromatic hydrocarbons and benzene in a cokery. Blood plasma proteins were separated by gel electrophoresis, transferred to a nitrocellulose membrane by Western blotting and detected by chemiluminescence using a monoclonal antibody as the primary antibody. There were no statistically significant differences between the exposed and the control groups in either the Polish or the Estonian samples. 相似文献
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Identification of a tight junction-associated guanine nucleotide exchange factor that activates Rho and regulates paracellular permeability 总被引:14,自引:0,他引:14
Benais-Pont G Punn A Flores-Maldonado C Eckert J Raposo G Fleming TP Cereijido M Balda MS Matter K 《The Journal of cell biology》2003,160(5):729-740
Rho family GTPases are important regulators of epithelial tight junctions (TJs); however, little is known about how the GTPases themselves are controlled during TJ assembly and function. We have identified and cloned a canine guanine nucleotide exchange factor (GEF) of the Dbl family of proto-oncogenes that activates Rho and associates with TJs. Based on sequence similarity searches and immunological and functional data, this protein is the canine homologue of human GEF-H1 and mouse Lfc, two previously identified Rho-specific exchange factors known to associate with microtubules in nonpolarized cells. In agreement with these observations, immunofluorescence of proliferating MDCK cells revealed that the endogenous canine GEF-H1/Lfc associates with mitotic spindles. Functional analysis based on overexpression and RNA interference in polarized MDCK cells revealed that this exchange factor for Rho regulates paracellular permeability of small hydrophilic tracers. Although overexpression resulted in increased size-selective paracellular permeability, such cell lines exhibited a normal overall morphology and formed fully assembled TJs as determined by measuring transepithelial resistance and by immunofluorescence and freeze-fracture analysis. These data indicate that GEF-H1/Lfc is a component of TJs and functions in the regulation of epithelial permeability. 相似文献
5.
Caspase-9 activation is critical for intrinsic cell death. The activity of caspase-9 is increased dramatically upon association with the apoptosome, and the apoptosome bound caspase-9 is the caspase-9 holoenzyme (C9Holo). In this study, we use quantitative enzymatic assays to fully characterize C9Holo and a leucine-zipper-linked dimeric caspase-9 (LZ-C9). We surprisingly show that LZ-C9 is more active than C9Holo for the optimal caspase-9 peptide substrate LEHD-AFC but is much less active than C9Holo for the physiological substrate procaspase-3. The measured Km values of C9Holo and LZ-C9 for LEHD-AFC are similar, demonstrating that dimerization is sufficient for catalytic activation of caspase-9. The lower activity of C9Holo against LEHD-AFC may be attributed to incomplete C9Holo assembly. However, the measured Km of C9Holo for procaspase-3 is much lower than that of LZ-C9. Therefore, in addition to dimerization, the apoptosome activates caspase-9 by enhancing its affinity for procaspase-3, which is important for procaspase-3 activation at the physiological concentration. 相似文献
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Irene Pila-Castellanos Diana Molino Joe McKellar Laetitia Lines Juliane Da Graca Marine Tauziet Laurent Chanteloup Ivan Mikaelian Laurne Meyniel-Schicklin Patrice Codogno Jacky Vonderscher Cdric Delevoye Olivier Moncorg Eric Meldrum Caroline Goujon Etienne Morel Benoit de Chassey 《PLoS pathogens》2021,17(2)
Influenza virus infections are major public health threats due to their high rates of morbidity and mortality. Upon influenza virus entry, host cells experience modifications of endomembranes, including those used for virus trafficking and replication. Here we report that influenza virus infection modifies mitochondrial morphodynamics by promoting mitochondria elongation and altering endoplasmic reticulum-mitochondria tethering in host cells. Expression of the viral RNA recapitulates these modifications inside cells. Virus induced mitochondria hyper-elongation was promoted by fission associated protein DRP1 relocalization to the cytosol, enhancing a pro-fusion status. We show that altering mitochondrial hyper-fusion with Mito-C, a novel pro-fission compound, not only restores mitochondrial morphodynamics and endoplasmic reticulum-mitochondria contact sites but also dramatically reduces influenza replication. Finally, we demonstrate that the observed Mito-C antiviral property is directly connected with the innate immunity signaling RIG-I complex at mitochondria. Our data highlight the importance of a functional interchange between mitochondrial morphodynamics and innate immunity machineries in the context of influenza viral infection. 相似文献
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Ga?lle Désaméricq Guillaume Dolbeau Christophe Verny Perrine Charles Alexandra Durr Katia Youssov Clémence Simonin Jean-Philippe Azulay Christine Tranchant Cyril Goizet Philippe Damier Emmanuel Broussolle Jean-Fran?ois Demonet Graca Morgado Laurent Cleret de Langavant Isabelle Macquin-Mavier Anne-Catherine Bachoud-Lévi Patrick Maison 《PloS one》2014,9(1)
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Patrick J. Hanley Zhuyong Mei Maria da Graca Cabreira-Hansen Mariola Klis Wei Li Yali Zhao April G. Durett Xingwu Zheng Yongping Wang Adrian P. Gee Edwin M. Horwitz 《Cytotherapy》2013,15(4):416-422
Mesenchymal stromal cells (MSCs) are multipotent progenitor cells capable of differentiating into adipocytes, osteoblasts and chondroblasts as well as secreting a vast array of soluble mediators. This potentially makes MSCs important mediators of a variety of therapeutic applications. They are actively under evaluation for immunomodulatory purposes such as graft-versus-host disease and Crohn’s disease as well as regenerative applications such as stroke and congestive heart failure. We report our method of generating clinical-grade MSCs together with suggestions gathered from manufacturing experience in our Good Manufacturing Practices facility. 相似文献