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11.
Attenuation of pattern recognition receptor signaling is mediated by a MAP kinase kinase kinase
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Sharon C Mithoe Christina Ludwig Michiel JC Pel Mara Cucinotta Alberto Casartelli Malick Mbengue Jan Sklenar Paul Derbyshire Silke Robatzek Corné MJ Pieterse Ruedi Aebersold Frank LH Menke 《EMBO reports》2016,17(3):441-454
Pattern recognition receptors (PRRs) play a key role in plant and animal innate immunity. PRR binding of their cognate ligand triggers a signaling network and activates an immune response. Activation of PRR signaling must be controlled prior to ligand binding to prevent spurious signaling and immune activation. Flagellin perception in Arabidopsis through FLAGELLIN‐SENSITIVE 2 (FLS2) induces the activation of mitogen‐activated protein kinases (MAPKs) and immunity. However, the precise molecular mechanism that connects activated FLS2 to downstream MAPK cascades remains unknown. Here, we report the identification of a differentially phosphorylated MAP kinase kinase kinase that also interacts with FLS2. Using targeted proteomics and functional analysis, we show that MKKK7 negatively regulates flagellin‐triggered signaling and basal immunity and this requires phosphorylation of MKKK7 on specific serine residues. MKKK7 attenuates MPK6 activity and defense gene expression. Moreover, MKKK7 suppresses the reactive oxygen species burst downstream of FLS2, suggesting that MKKK7‐mediated attenuation of FLS2 signaling occurs through direct modulation of the FLS2 complex. 相似文献
12.
The endocannabinoid arachidonylethanolamide (AEA, anandamide) is an endogenous ligand for the cannabinoid receptors and has been shown to be oxygenated by cyclooxygenase-2 (COX-2). We examined the structural requirements for COX-mediated, AEA oxygenation using a number of substrate analogues and site-directed mutants of COX-2. Fourteen AEA analogues were synthesized and tested as COX substrates. These studies identified the hydroxyl moiety of AEA as a critical determinant in the ability of COX enzymes to effect robust endocannabinoid oxygenation. In addition, these studies suggest that subtle structural modifications of AEA analogues near the ethanolamide moiety can result in pronounced changes in their ability to serve as COX-2 substrates. Site-directed mutagenesis studies have permitted the development of a model of AEA binding within the COX-2 active site. As with arachidonic acid, the omega-terminus of AEA binds in a hydrophobic alcove near the top of the COX-2 active site. The polar ethanolamide moiety of AEA, like the carboxylate of arachidonate, interacts with Arg-120 at the bottom of the COX-2 active site. Mutation of Tyr-385 prevents AEA oxygenation, suggesting that, as in the case of other COX substrates, AEA metabolism is initiated by Tyr-385-mediated hydrogen abstraction. Thus, AEA binds within the COX-2 active site in a conformation roughly similar to that of arachidonic acid. However, important differences have been identified that account for the isoform selectivity of AEA oxygenation. Importantly, the COX-2 side pocket and Arg-513 in particular are critical determinants of the ability of COX-2 to efficiently generate prostaglandin H(2) ethanolamide. The reduced efficiency of COX-1-mediated, AEA oxygenation can thus be explained by the absence of an arginine residue at position 513 in this isoform. Mutational analysis of Leu-531, an amino acid located directly across from the COX-2 side pocket, suggests that AEA is shifted away from this hydrophobic residue and toward Arg-513 relative to arachidonic acid. Coupled with earlier observations with the endocannabinoid 2-arachidonylglycerol, these results indicate that one possible function of the highly conserved COX-2 active site side pocket is to promote endocannabinoid oxygenation. 相似文献
13.
Germline transformation of the silkworm Bombyx mori L. using a piggyBac transposon-derived vector 总被引:21,自引:0,他引:21
Tamura T Thibert C Royer C Kanda T Abraham E Kamba M Komoto N Thomas JL Mauchamp B Chavancy G Shirk P Fraser M Prudhomme JC Couble P Toshiki T Chantal T Corinne R Toshio K Eappen A Mari K Natuo K Jean-Luc T Bernard M Gérard C Paul S Malcolm F Jean-Claude P Pierre C 《Nature biotechnology》2000,18(1):81-84
We have developed a system for stable germline transformation in the silkworm Bombyx mori L. using piggyBac, a transposon discovered in the lepidopteran Trichoplusia ni. The transformation constructs consist of the piggyBac inverted terminal repeats flanking a fusion of the B. mori cytoplasmic actin gene BmA3 promoter and the green fluorescent protein (GFP). A nonautonomous helper plasmid encodes the piggyBac transposase. The reporter gene construct was coinjected into preblastoderm eggs of two strains of B. mori. Approximately 2% of the individuals in the G1 broods expressed GFP. DNA analyses of GFP-positive G1 silkworms revealed that multiple independent insertions occurred frequently. The transgene was stably transferred to the next generation through normal Mendelian inheritance. The presence of the inverted terminal repeats of piggyBac and the characteristic TTAA sequence at the borders of all the analyzed inserts confirmed that transformation resulted from precise transposition events. This efficient method of stable gene transfer in a lepidopteran insect opens the way for promising basic research and biotechnological applications. 相似文献
14.
1-Thio-beta-D-galactofuranosides: synthesis and evaluation as beta-D- galactofuranosidase inhibitors
Marino C; Marino K; Miletti L; Manso Alves MJ; Colli W; de Lederkremer RM 《Glycobiology》1998,8(9):901-904
Beta-D-galactofuranosidase is a good chemotherapeutic target for the design
of inhibitors, since beta-D-galactofuranose is a constituent of important
parasite glycoconjugates but is not present in the host mammals. With this
aim, we have synthesized for the first time alkyl, benzyl and aryl
1-thio-beta-D-galactofuranosides by condensation of
penta-O-benzoyl-alpha,beta-D-galactofuranose with the corresponding thiols,
in the presence of SnCl4as catalyst. The complete chemical and
spectroscopical characterization of these compounds showed that the
reaction was stereoselective. Debenzoylation with sodium methoxide afforded
the beta-S-galactofuranosides in high yield. The thioglycosides were tested
as inhibitors of the beta-D- galactofuranosidase of Penicillium fellutanum,
using for the first time 4-nitrophenyl-beta-D-galactofuranoside as
chromogenic substrate. The 4- aminophenyl-1-thio-beta-D-galactofuranoside,
obtained by catalytic hydrogenation of the nitrophenyl derivative, was the
best inhibitor being then an adequate ligand for the preparation of an
affinity phase aimed at the isolation of beta-d-galactofuranosidases from
different sources. Also the inhibitory activity of d-galactono-1, 4-lactone
was shown.
相似文献
15.
16.
M Alonso N Alonso Rodriguez C Garzelli M Martínez Lirola M Herranz S Samper MJ Ruiz Serrano E Bouza D García de Viedma 《BMC microbiology》2010,10(1):151
Background
The Beijing lineage of Mycobacterium tuberculosis is causing concern due to its global distribution and its involvement in severe outbreaks. Studies focused on this lineage are mainly restricted to geographical settings where its prevalence is high, whereas those in other areas are scarce. In this study, we analyze Beijing isolates in the Mediterranean area, where this lineage is not prevalent and is mainly associated with immigrant cases. 相似文献17.
Jason A Roberts Michael S Roberts Andrew Semark Andrew A Udy Carl MJ Kirkpatrick David L Paterson Matthew J Roberts Peter Kruger Jeffrey Lipman 《BMC anesthesiology》2011,11(1):1-7
Background
Critical illness, mediated by trauma or sepsis, can lead to physiological changes that alter the pharmacokinetics of antibiotics and may result in sub-therapeutic concentrations at the sites of infection. The first aim of this project is to identify the clinical characteristics of critically ill patients with significant trauma that have been recently admitted to ICU that may predict the dosing requirements for the antibiotic, cefazolin. The second aim of this is to identify the clinical characteristics of critically ill patients with sepsis that may predict the dosing requirements for the combination antibiotic, piperacillin-tazobactam.Methods/Design
This is an observational pharmacokinetic study of patients with trauma (cefazolin) or with sepsis (piperacillin-tazobactam). Participants will have samples from blood and urine, collected at different intervals. Patients will also have a microdialysis catheter inserted into subcutaneous tissue to measure interstitial fluid penetration of the antibiotic. Participants will be administered sinistrin, indocyanine green and sodium bromide as well as have cardiac output monitoring performed and tetrapolar bioimpedance to determine physiological changes resulting from pathology. Analysis of samples will be performed using validated liquid chromatography tandem mass-spectrometry. Pharmacokinetic analysis will be performed using non-linear mixed effects modeling to determine individual and population pharmacokinetic parameters of antibiotics.Discussion
The study will describe cefazolin and piperacillin-tazobactam concentrations in plasma and the interstitial fluid of tissues in trauma and sepsis patients respectively. The results of this study will guide clinicians to effectively dose these antibiotics in order to maximize the concentration of antibiotics in the interstitial fluid of tissues. 相似文献18.
Bakker MF Verstappen SM Welsing PM Jacobs JW Jahangier ZN van der Veen MJ Bijlsma JW Lafeber FP;Utrecht Arthritis Cohort study group 《Arthritis research & therapy》2011,13(3):R70
Introduction
The aim of this study was to investigate whether serum biomarker levels of C2C, C1,2C, CS846, and CPII can predict the long-term course of disease activity and radiographic progression early in the disease course of rheumatoid arthritis (RA). 相似文献19.
Kalgutkar AS Crews BC Saleh S Prudhomme D Marnett LJ 《Bioorganic & medicinal chemistry》2005,13(24):6810-6822
Previous studies from our laboratory have revealed that esterification/amidation of the carboxylic acid moiety in the nonsteroidal anti-inflammatory drug, indomethacin, generates potent and selective COX-2 inhibitors. In the present study, a series of reverse ester/amide derivatives were synthesized and evaluated as selective COX-2 inhibitors. Most of the reverse esters/amides displayed time-dependent COX-2 inhibition with IC50 values in the low nanomolar range. Replacement of the 4-chlorobenzoyl group on the indole nitrogen with a 4-bromobenzyl moiety resulted in compounds that retained selective COX-2 inhibitory potency. In addition to inhibiting COX-2 activity in vitro, the reverse esters/amides also inhibited COX-2 activity in the mouse macrophage-like cell line, RAW264.7. Overall, this strategy broadens the scope of our previous methodology of neutralizing the carboxylic acid group in NSAIDs as a means of generating COX-2-selective inhibitors and is potentially applicable to other NSAIDs. 相似文献
20.
Stem cell self-renewal versus differentiation fate decisions are difficult to characterize and analyze due to multiple competing rate processes occurring simultaneously among heterogeneous cell subpopulations. To address this challenge, we describe a mathematical model for cell population dynamics that allows flow cytometry measurement of population distributions of molecular markers to be deconvoluted in terms of subpopulation-specific rate parameters distinguishing commitment to differentiation, proliferation of differentiated cells, and proliferation of undifferentiated cells (i.e., self-renewal). We validate this model-based parameter determination by means of dedicated, independent cell-tracking studies. Our approach facilitates interpretation of relationships underlying effects of external cues on cell responses in differentiating cultures via intracellular signals. 相似文献