51 research outputs found

    Enantioselective Synthesis of 2,3-Disubstituted Indanones via Pd-Catalyzed Intramolecular Asymmetric Allylic Alkylation of Ketones

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    A Pd-catalyzed intramolecular asymmetric allylic alkylation (AAA) reaction with “hard” carbanions has been developed for the first time, affording 2,3-disubstituted indanones with high diastereo- and enantioselectivities. The transformation of these products into other core structures of natural products has been demonstrated

    Histological and body weight changes in mucosal irritation test: A–C.

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    <p>Panels A1–A3 show photomicrographs of the colon sections (×10).Panels B1–B3 show photomicrographs of the anus sections (×40). Panel C shows body weight changes.</p

    Structural Chemistry and Excellent Nonlinear Optical Properties of a Series of Ternary Selenides Ga<sub><i>x</i></sub>In<sub>2–<i>x</i></sub>Se<sub>3</sub>

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    Novel nonlinear optical (NLO) materials possessing simple chemical compositions and facile syntheses are competitive when considering their practical application. Here, a series of ternary selenides GaxIn2–xSe3 (x = 0.07, 0.38, 0.45, and 0.81) that crystallize in a chiral P65 structure are obtained by melting Ga, In, and Se elements. Their three-dimensional structures are built by (Ga/In)­Se4 tetrahedra and InSe5 trigonal bipyramids. The hexagonal modification’s phase stability is analyzed by energy calculation, and their optical band gaps are determined to be 1.72–1.99 eV. They exhibit large NLO responses that are 1.41–1.64 times that of the benchmark AgGaS2. The results of density functional theory calculations suggest that introduction of Ga onto the In site in (InSe4)5– units can form a deformed tetrahedron with more distortion in the structure, and the (InSe5)7– units contribute a large amount of birefringence to the structure. This work is the first to investigate the ternary chalcogenides M2Q3 (M = Ga or In; Q = S or Se) as new types of infrared NLO crystals with excellent performances, which will stimulate more interest in those possessing simple compositions and outstanding performances

    N‑Linked Glycoproteome Profiling of Seedling Leaf in <i>Brachypodium distachyon</i> L.

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    <i>Brachypodium distachyon</i> L., a model plant for cereal crops, has become important as an alternative and potential biofuel grass. In plants, N-glycosylation is one of the most common and important protein modifications, playing important roles in signal recognition, increase in protein activity, stability of protein structure, and formation of tissues and organs. In this study, we performed the first glycoproteome analysis in the seedling leaves of <i>B. distachyon</i>. Using lectin affinity chromatography enrichment and mass-spectrometry-based analysis, we identified 47 glycosylation sites representing 46 N-linked glycoproteins. Motif-X analysis showed that two conserved motifs, N-X-T/S (X is any amino acid, except Pro), were significantly enriched. Further functional analysis suggested that some of these identified glycoproteins are involved in signal transduction, protein trafficking, and quality control and the modification and remodeling of cell-wall components such as receptor-like kinases, protein disulfide isomerase, and polygalacturonase. Moreover, transmembrane helices and signal peptide prediction showed that most of these glycoproteins could participate in typical protein secretory pathways in eukaryotes. The results provide a general overview of protein N-glycosylation modifications during the early growth of seedling leaves in <i>B. distachyon</i> and supplement the glycoproteome databases of plants

    Comparative Phosphoproteome Analysis of the Developing Grains in Bread Wheat (<i>Triticum aestivum</i> L.) under Well-Watered and Water-Deficit Conditions

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    Wheat (Triticum aestivum), one of the most important cereal crops, is often threatened by drought. In this study, water deficit significantly reduced the height of plants and yield of grains. To explore further the effect of drought stress on the development and yield of grains, we first performed a large scale phosphoproteome analysis of developing grains in wheat. A total of 590 unique phosphopeptides, representing 471 phosphoproteins, were identified under well-watered conditions. Motif-X analysis showed that four motifs were enriched, including [sP], [Rxxs], [sDxE], and [sxD]. Through comparative phosphoproteome analysis between well-watered and water-deficit conditions, we found that 63 unique phosphopeptides, corresponding to 61 phosphoproteins, showed significant changes in phosphorylation level (≥2-fold intensities). Functional analysis suggested that some of these proteins may be involved in signal transduction, embryo and endosperm development of grains, and drought response and defense under water-deficit conditions. Moreover, we also found that some chaperones may play important roles in protein refolding or degradation when the plant is subjected to water stress. These results provide a detailed insight into the stress response and defense mechanisms of developmental grains at the phosphoproteome level. They also suggested some potential candidates for further study of transgenosis and drought stress as well as incorporation into molecular breeding for drought resistance
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