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101.
The acylation state of mycobacterial lipomannans modulates innate immunity response through toll-like receptor 2 总被引:6,自引:0,他引:6
Detection of Mycobacterium tuberculosis antigens by professional phagocytes via toll-like receptors (TLR) contributes to controlling chronic M. tuberculosis infection. Lipomannans (LM), which are major lipoglycans of the mycobacterial envelope, were recently described as agonists of TLR2 with potent activity on proinflammatory cytokine regulation. LM correspond to a heterogeneous population of acyl- and glyco-forms. We report here the purification and the complete structural characterization of four LM acyl-forms from Mycobacterium bovis BCG using MALDI MS and 2D (1)H-(31)P NMR analyses. All this biochemical work provided the tools to investigate the implication of LM acylation degree on its proinflammatory activity. The latter was ascribed to the triacylated LM form, essentially an agonist of TLR2, using TLR2/TLR1 heterodimers for signaling. Altogether, these findings shed more light on the molecular basis of LM recognition by TLR. 相似文献
102.
Lasserre JP Beyne E Pyndiah S Lapaillerie D Claverol S Bonneu M 《Electrophoresis》2006,27(16):3306-3321
Study of the complexome - all the protein complexes of the cell - is essential for a better understanding and more global vision of cell function. Using two-dimensional blue native/SDS-PAGE (2-D BN/SDS-PAGE) technology, the cytosolic and membrane protein complexes of Escherichia coli were separated. Then, the different partners of each protein complex were identified by LC-MS/MS. In this report, 306 protein complexes were separated and identified. Among these protein complexes, 50 heteromultimeric and 256 homomultimeric protein complexes were found. Among the 50 heteromultimeric protein complexes, 18 previously described protein complexes validate the technology. In this study, 109 new protein complexes were found, providing insight into the function of previously uncharacterized bacterial proteins. 相似文献
103.
The flavone apigenin occurs in many leafy vegetables and fruits. It has been reported to have cancer chemopreventive efficacy in rodents. An HPLC method described previously for the determination of tricin, the dimethoxy cogener of apigenin, was modified and validated for measurement of apigenin in mouse tissues. Separation was carried out on a Hypersil-BDS C(18) column (4.6 x 250 mm) with an isocratic mobile phase of 55% methanol in 0.1 m ammonium acetate, pH 5.10, containing 0.27 mm disodium ethylenediamine tetraacetic acid. UV detection was at 336 nm, without interference from endogenous tissue compounds. The assay was linear in the range 25-400 ng/mL, 0.25-4 microg/mL and 2.5-40 microg/mL, with r(2) > 0.99 in all cases, for mouse plasma, liver and intestinal mucosa, respectively. Apigenin in mouse plasma, liver and intestinal mucosa was efficiently extracted with 0.1 m acetic acid in acetone. The assay recovery at low, medium and high concentrations was between 94.6 and 131.7% for all biomatrices, with a relative standard deviation of <10%. The lower limit of quantification for plasma was 25 ng/mL with a relative standard deviation of <15%. The method was used to measure the steady-phase apigenin levels in tissues of mice receiving apigenin in their diet. 相似文献
104.
In this paper we show the existence of global minimizers for the geometrically non-linear equations of elastic plates, in the framework of the general 6-parameter shell theory. A characteristic feature of this model for shells is the appearance of two independent kinematic fields: the translation vector field and the rotation tensor field (representing in total 6 independent scalar kinematic variables). For isotropic plates, we prove the existence theorem by applying the direct methods of the calculus of variations. Then, we generalize our existence result to the case of anisotropic plates. 相似文献
105.
Savonnet M Camarata A Canivet J Bazer-Bachi D Bats N Lecocq V Pinel C Farrusseng D 《Dalton transactions (Cambridge, England : 2003)》2012,41(14):3945-3948
We successively introduce new catalytic centers through click reaction into MOFs and modify their environment by addition of lipophilic groups. The resulting bifunctionalized MOF provides an optimized balance between basicity and lipophilicity and shows outstanding performance for the transesterification reaction. 相似文献
106.
Dr. Delphine Crozet Dr. Aitor Gual Dr. David McKay Dr. Chiara Dinoi Dr. Cyril Godard Prof. Martine Urrutigoïty Dr. Jean‐Claude Daran Prof. Laurent Maron Prof. Carmen Claver Prof. Philippe Kalck 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(23):7128-7140
The reactivity of [Rh(CO)2{(R,R)‐Ph? BPE}]BF4 ( 2 ) toward amine, CO and/or H2 was examined by high‐pressure NMR and IR spectroscopy. The two cationic pentacoordinated species [Rh(CO)3{(R,R)‐Ph? BPE}]BF4 ( 4 ) and [Rh(CO)2(NHC5H10){(R,R)‐Ph‐BPE}]BF4 ( 8 ) were identified. The transformation of 2 into the neutral complex [RhH(CO)2{(R,R)‐Ph? BPE}] ( 3 ) under hydroaminomethylation conditions (CO/H2, amine) was investigated. The full mechanisms related to the formation of 3 , 4 and 8 starting from 2 are supported by DFT calculations. In particular, the pathway from 2 to 3 revealed the deprotonation by the amine of the dihydride species [Rh(H)2(CO)2{(R,R)‐Ph? BPE}]BF4 ( 6 ), resulting from the oxidative addition of H2 on 2 . 相似文献
107.
Antoine Leydier Yi Lin Guilhem Arrachart Raphaël Turgis Delphine Lecerclé Alain Favre-Reguillon Frédéric Taran Marc Lemaire Stéphane Pellet-Rostaing 《Tetrahedron》2012,68(4):1163-1170
Synthesis of modified EDTA and DTPA ligands and determination of their binding affinities for the uranyl cation are described.Thanks to a screening method, based on a chromophoric complex displacement procedure, chelating properties were studied in aqueous media under various pH conditions for evaluation of their in vivo uranyl-removal efficacy. Each ligand showed a more or less pronounced affinity for uranium. Specific ligands based on EDTA or DTPA analogues containing sulfocatecholamide (CAMS) were found to exhibit a significant affinity towards uranyl ion in acidic, neutral or basic conditions. 相似文献
108.
Delphine Declerck Albert Nguyen Van Nhien Solen Josse Jan Szymoniak Philippe Bertus Claudia Bello Pierre Vogel Denis Postel 《Tetrahedron》2012,68(6):1802-1809
The titanium-mediated cyclopropanation reaction using Ti(OiPr)3Me/EtMgBr/BF3·OEt2 has been applied to various 2-cyanopyrrolidines for the synthesis of functionalized 2-(1-aminocyclopropyl)pyrrolidine-3,4-diol derivatives (dideoxyiminoalditols). Under the same experimental conditions the trans-5-azidomethyl-2-cyanopyrrolidine derivative was not cyclopropanated but reduced into the corresponding 5-amino-2-cyano derivative. After polyol deprotection 2-(1-aminocyclopropyl)pyrrolidine-3,4-diols were obtained and their inhibitory activity towards 13 glycosidases has been evaluated. (2S,3S,4R,5S)-2-(1-Aminocyclopropyl)-5-methylpyrrolidine-3,4-diol (38), which has the same absolute configuration as l-fucose, is a moderate (IC50=44 μM), but selective, inhibitor of α-l-fucosidase from human placenta. 相似文献
109.
L Ruhlmann D Schaming I Ahmed A Courville J Canny R Thouvenot 《Inorganic chemistry》2012,51(15):8202-8211
The reaction of the trivacant Dawson polyoxometalate α-[P(2)W(15)O(56)](12-) and the divalent cations Co(2+) is known to form a symmetrically derived sandwich complex of formula ββ-[Co(4)(H(2)O)(2)(P(2)W(15)O(56))(2)](16-) [symbolized as ββ-Co(4)(P(2)W(15))(2)] at low pH (ca. pH 3). We have shown previously that, by a slight modification of the reaction conditions, trinuclear αβ-[(NaOH(2))Co(3)(H(2)O)(P(2)W(15)O(56))(2)](17-) and dinuclear [(NaOH(2))(2)Co(2)(P(2)W(15)O(56))(2)](18-) complexes [symbolized as αβ-NaCo(3)(P(2)W(15))(2) and Na(2)Co(2)(P(2)W(15))(2), respectively] can be synthesized as aqueous-soluble sodium salts. αβ-NaCo(3)(P(2)W(15))(2) is a "lacunary" sandwich complex that can add a Co(2+) cation to form nearly quantitatively an unsymmetrical Dawson tetracobalt sandwich polyoxometalate, αβ-[Co(4)(H(2)O)(2)(P(2)W(15)O(56))(2)](16-) [symbolized as αβ-Co(4)(P(2)W(15))(2)]. Thus, for Co(4)(P(2)W(15))(2), the junctions between the trivacant {P(2)W(15)} subunits and the central tetrameric unit can be either both β type or β and α types. The interconversion between αβ-Co(4)(P(2)W(15))(2) and ββ-Co(4)(P(2)W(15))(2) and the decomplexation process at low pH, leading to the formation of αβ-NaCo(3)(P(2)W(15))(2) and/or Na(2)Co(2)(P(2)W(15))(2), have been followed in aqueous solution at various pH values by electrochemistry, UV-visible absorption spectroscopy, and (31)P NMR spectroscopy. 相似文献
110.
J. Osterwalder T. Greber E. Wetli J. Wider H. J. Neff 《Progress in Surface Science》2000,64(3-8):65-87
The routine measurement of full hemispherical photoemission intensity maps gives us the possibility for the combined investigation of structural and electronic phenomena at surfaces. As an example the growth of ultrathin films of Co on Cu(111) is studied as a function of film thickness. While X-ray photoelectron diffraction (XPD) shows the early appearance of stacking faults as a precursor of the hcp structure, Fermi surface maps reveal the very fast evolution of the Co Fermi surface that can be compared to measurements on a clean Co(0001) crystal. For the system O/Rh(111), XPD brings up important structural clues, relating changes in surface reactivity to small amounts of subsurface oxygen, which forces adjacent oxygen atoms to occupy new and more reactive adsorption sites. In the course of this last study we observed for the first time the weak backscattering signals in the angular pattern of adsorbate emission. These cone-like features are extremely sensitive to the adsorbate–substrate bond length. 相似文献