排序方式: 共有165条查询结果,搜索用时 171 毫秒
121.
Yoann Rombouts Hulda S. Jónasdóttir Agnes L. Hipgrave Ederveen Karli R. Reiding Bas C. Jansen Jona Freysdottir Ingibjörg Hardardottir Andreea Ioan-Facsinay Martin Giera Manfred Wuhrer 《Glycoconjugate journal》2016,33(3):457-470
Murine zymosan-induced peritonitis is a widely used model for studying the molecular and cellular events responsible for the initiation, persistence and/or resolution of inflammation. Among these events, it is becoming increasingly evident that changes in glycosylation of proteins, especially in the plasma and at the site of inflammation, play an important role in the inflammatory response. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS)-based glycosylation profiling, we investigated the qualitative and quantitative effect of zymosan-induced peritonitis on N-glycosylation in mouse plasma and peritoneal fluid. Our results show that both N-glycomes exhibit highly similar glycosylation patterns, consisting mainly of diantennary and triantennary complex type N-glycans with high levels (>95 %) of galactosylation and sialylation (mostly NeuGc) and a medium degree of core fucosylation (30 %). Moreover, MS/MS structural analysis, assisted by linkage-specific derivatization of sialic acids, revealed the presence of O-acetylated sialic acids as well as disialylated antennae (“branching sialylation”) characterized by the presence of α2-6-linked NeuGc on the GlcNAc of the NeuGcα2-3-Galβ1-3-GlcNAc terminal motif. A significant decrease of (core) fucosylation together with an increase of both α2-3-linked NeuGc and “branching sialylation” were observed in N-glycomes of mice challenged with zymosan, but not in control mice injected with PBS. Importantly, substantial changes in glycosylation were already observed 12 h after induction of peritonitis, thereby demonstrating an unexpected velocity of the biological mechanisms involved. 相似文献
122.
Domestication of a housekeeping transglycosylase for assembly of a Type VI secretion system 下载免费PDF全文
The type VI secretion system (T6SS) is an anti‐bacterial weapon comprising a contractile tail anchored to the cell envelope by a membrane complex. The TssJ, TssL, and TssM proteins assemble a 1.7‐MDa channel complex that spans the cell envelope, including the peptidoglycan layer. The electron microscopy structure of the TssJLM complex revealed that it has a diameter of ~18 nm in the periplasm, which is larger than the size of peptidoglycan pores (~2 nm), hence questioning how the T6SS membrane complex crosses the peptidoglycan layer. Here, we report that the MltE housekeeping lytic transglycosylase (LTG) is required for T6SS assembly in enteroaggregative Escherichia coli. Protein–protein interaction studies further demonstrated that MltE is recruited to the periplasmic domain of TssM. In addition, we show that TssM significantly stimulates MltE activity in vitro and that MltE is required for the late stages of T6SS membrane complex assembly. Collectively, our data provide the first example of domestication and activation of a LTG encoded within the core genome for the assembly of a secretion system. 相似文献
123.
Salimata Bagayoko Stephen Adonai Leon-Icaza Miriam Pinilla Audrey Hessel Karin Santoni David Pricat Pierre-Jean Bordignon Flavie Moreau Elif Eren Aurlien Boyanc Emmanuelle Naser Lise Lefvre Cline Berrone Nino Iakobachvili Arnaud Metais Yoann Rombouts Geanncarlo Lugo-Villarino Agns Coste Ina Attre Dara W. Frank Hans Clevers Peter J. Peters Cline Cougoule Rmi Plans Etienne Meunier 《PLoS pathogens》2021,17(9)
Regulated cell necrosis supports immune and anti-infectious strategies of the body; however, dysregulation of these processes drives pathological organ damage. Pseudomonas aeruginosa expresses a phospholipase, ExoU that triggers pathological host cell necrosis through a poorly characterized pathway. Here, we investigated the molecular and cellular mechanisms of ExoU-mediated necrosis. We show that cellular peroxidised phospholipids enhance ExoU phospholipase activity, which drives necrosis of immune and non-immune cells. Conversely, both the endogenous lipid peroxidation regulator GPX4 and the pharmacological inhibition of lipid peroxidation delay ExoU-dependent cell necrosis and improve bacterial elimination in vitro and in vivo. Our findings also pertain to the ExoU-related phospholipase from the bacterial pathogen Burkholderia thailandensis, suggesting that exploitation of peroxidised phospholipids might be a conserved virulence mechanism among various microbial phospholipases. Overall, our results identify an original lipid peroxidation-based virulence mechanism as a strong contributor of microbial phospholipase-driven pathology. 相似文献
124.
A cDNA encoding insulin-degrading enzyme (IDE) was cloned from tomato (Solanum lycopersicum) and expressed in Escherichia coli in N-terminal fusion with glutathione S-transferase. GST-SlIDE was characterized as a neutral thiol-dependent metallopeptidase with insulinase activity: the recombinant enzyme cleaved the oxidized insulin B chain at eight peptide bonds, six of which are also targets of human IDE. Despite a certain preference for proline in the vicinity of the cleavage site, synthetic peptides were cleaved at apparently stochastic positions indicating that SlIDE, similar to IDEs from other organisms, does not recognize any particular amino acid motif in the primary structure of its substrates. Under steady-state conditions, an apparent K(m) of 62+/-7 microm and a catalytic efficiency (k(cat)/K(m)) of 62+/-15 mm(-1) s(-1) were determined for Abz-SKRDPPKMQTDLY(NO(3))-NH(2) as the substrate. GST-SlIDE was effectively inhibited by ATP at physiological concentrations, suggesting regulation of its activity in response to the energy status of the cell. While mammalian and plant IDEs share many of their biochemical properties, this similarity does not extend to their function in vivo, because insulin and the beta-amyloid peptide, well-established substrates of mammalian IDEs, as well as insulin-related signaling appear to be absent from plant systems. 相似文献
125.
Diego Pavn‐Jordn Anthony D. Fox Preben Clausen Mindaugas Dagys Bernard Deceuninck Koen Devos Richard D. Hearn Chas A. Holt Menno Hornman Verena Keller Tom Langendoen ukasz awicki Svein H. Lorentsen Leho Luiguje Wodzimierz Meissner Petr Musil Leif Nilsson Jean‐Yves Paquet Antra Stipniece David A. Stroud Johannes Wahl Marco Zenatello Aleksi Lehikoinen 《Diversity & distributions》2015,21(5):571-582
126.
Philip J.M. Brouwer Mitch Brinkkemper Pauline Maisonnasse Nathalie Dereuddre-Bosquet Marloes Grobben Mathieu Claireaux Marlon de Gast Romain Marlin Virginie Chesnais Ségolène Diry Joel D. Allen Yasunori Watanabe Julia M. Giezen Gius Kerster Hannah L. Turner Karlijn van der Straten Cynthia A. van der Linden Yoann Aldon Rogier W. Sanders 《Cell》2021,184(5):1188-1200.e19
127.
Jean-Michel Escoffre Chloé Mauroy Thomas Portet Luc Wasungu Chrystelle Rosazza Yoann Gilbart Laetitia Mallet Elisabeth Bellard Muriel Golzio Marie-Pierre Rols Justin Teissié 《Biophysical reviews》2009,1(4)
Electropulsation is one of the nonviral methods successfully used to deliver genes into living cells in vitro and in vivo. This approach shows promise in the field of gene and cellular therapies. The present review focuses on the processes supporting gene electrotransfer in vitro. In the first part, we will report the events occurring before, during, and after pulse application in the specific field of plasmid DNA electrotransfer at the cell level. A critical discussion of the present theoretical considerations about membrane electropermeabilization and the transient structures involved in the plasmid uptake follows in a second part. 相似文献
128.
Yoann Lussier Pierre Bissonnette Daniel G. Bichet Jean-Yves Lapointe 《The Journal of membrane biology》2010,236(2):225-232
Myo-inositol (MI; hexahydroxycyclohexane, C6H6O12) is a small neutral molecule used as a compatible osmolyte in the kidney medulla. At high concentrations, MI appears to act
as a chemical chaperone and was shown to promote plasma membrane expression of the impaired cystic fibrosis chloride channel
(Δ508-CFTR). In the present study, we measured whether MI could increase expression of two human aquaporin 2 (AQP2) mutants
which were recently identified as causing nephrogenic diabetes insipidus (NDI). Both proteins (D150E and G196D) were expressed
in Xenopus laevis oocytes, but only D150E displayed an increase in oocyte water permeability (P
f). Adding 5 mM MI to the bathing solution for 24 h produced a 50% increase in the D150E-associated P
f, while it had no effect on noninjected oocytes or on oocytes expressing wt-AQP2 or G196D. Western blots performed on purified
plasma membrane preparations confirmed that MI increased the amount of D150E present at the plasma membrane, while G196D was
always undetectable. X. laevis oocytes are remarkably impermeable to MI, and the effect of MI on D150E expression does not require the presence of intracellular
MI. The effect of external MI was dose-dependent (K
0.5 was 130 μM) and specific with respect to other forms of inositols. Further studies on a second group of AQP2 mutants causing
NDI showed that K228E activity was similarly stimulated by MI, while V71M, A70D and S256L were not. It is concluded that physiological
concentrations of extracellular MI can stimulate the expression of a specific subgroup of AQP2 mutants. 相似文献
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130.
Maria Májeková Taavi Paal Nichola S. Plowman Michala Bryndová Liis Kasari Anna Norberg Matthias Weiss Tom R. Bishop Sarah H. Luke Katerina Sam Yoann Le Bagousse-Pinguet Jan Lep? Lars G?tzenberger Francesco de Bello 《PloS one》2016,11(2)
Functional diversity (FD) is an important component of biodiversity that quantifies the difference in functional traits between organisms. However, FD studies are often limited by the availability of trait data and FD indices are sensitive to data gaps. The distribution of species abundance and trait data, and its transformation, may further affect the accuracy of indices when data is incomplete. Using an existing approach, we simulated the effects of missing trait data by gradually removing data from a plant, an ant and a bird community dataset (12, 59, and 8 plots containing 62, 297 and 238 species respectively). We ranked plots by FD values calculated from full datasets and then from our increasingly incomplete datasets and compared the ranking between the original and virtually reduced datasets to assess the accuracy of FD indices when used on datasets with increasingly missing data. Finally, we tested the accuracy of FD indices with and without data transformation, and the effect of missing trait data per plot or per the whole pool of species. FD indices became less accurate as the amount of missing data increased, with the loss of accuracy depending on the index. But, where transformation improved the normality of the trait data, FD values from incomplete datasets were more accurate than before transformation. The distribution of data and its transformation are therefore as important as data completeness and can even mitigate the effect of missing data. Since the effect of missing trait values pool-wise or plot-wise depends on the data distribution, the method should be decided case by case. Data distribution and data transformation should be given more careful consideration when designing, analysing and interpreting FD studies, especially where trait data are missing. To this end, we provide the R package “traitor” to facilitate assessments of missing trait data. 相似文献