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The fixation of carbon dioxide (CO2) with epoxide to form cyclic carbonates is industrially important because of the high economic value of the products. Quaternized carbon dots have great potential in CO2 cycloaddition under their high activity and facile synthesis without cocatalysts. Herein, novel quaternized carbon dots were synthesized through a microwave method using citric acid and ethanolamine with different amounts of (2-bromoethyl)trimethylammonium bromide (Br-CDs) or (2-chloroethyl)trimethylammonium chloride (Cl-CDs). All carbon dots were characterized by TEM, XPS, FT-IR, UV-vis and zeta potential analyses as well as elemental analysis. Br1-CD showed the best catalytic activity (99%) and selectivity (99%) for CO2 cycloaddition with styrene oxide to 4-phenyl-1,3-dioxolan-2-one under suitable conditions (120 °C, 8 h, and 0.1 MPa). Furthermore, the catalyst can be easily recycled up to five times. [ABSTRACT FROM AUTHOR]

Multiple organellar RNA editing factor (MORF) complex was shown to be highly associated with C‐to‐U RNA editing of vascular plant editosome. However, mechanisms by which MORF9‐dependent plastid RNA editing controls plant development and responses to environmental alteration remain obscure. In this study, we found that loss of MORF9 function impaired PSII efficiency, NDH activity, and carbohydrate production, rapidly promoted nuclear gene expression including sucrose transporter and sugar/energy responsive genes, and attenuated root growth under sugar starvation conditions. Sugar repletion increased MORF9 and MORF2 expression in wild‐type seedlings and reduced RNA editing of matK‐706, accD‐794, ndhD‐383 and ndhF‐290 in the morf9 mutant. RNA editing efficiency of ndhD‐383 and ndhF‐290 sites was diminished in the gin2/morf9 double mutants, and that of matK‐706, accD‐794, ndhD‐383 and ndhF‐290 sites were significantly diminished in the snrk1/morf9 double mutants. In contrast, overexpressing HXK1 or SnRK1 promoted RNA editing rate of matK‐706, accD‐794, ndhD‐383 and ndhF‐290 in leaves of morf9 mutants, suggesting that HXK1 partially impacts MORF9 mediated ndhD‐383 and ndhF‐290 editing, while SnRK1 may only affect MORF9‐mediated ndhF‐290 site editing. Collectively, these findings suggest that sugar and/or its intermediary metabolites impair MORF9‐dependent plastid RNA editing resulting in derangements of plant root development. Summary statement: Sugar supplementation alters MORF9 levels and MORF9‐dependent plastid RNA editing, which in turn affects nuclear gene expression and root growth in Arabidopsis, suggesting that plastid RNA editing regulates auxin‐related root growth and sugar starvation response via a retrograde signalling pathway. [ABSTRACT FROM AUTHOR]

Carbon dots with good photoelectric properties are usually used as photocatalysts and electrocatalysts, but the good catalytic performance of carbon dots as nanomaterials for thermal catalysis is ignored. Herein, the application of novel efficient catalysts based on carbon dots for the transformation of carbon dioxide (CO2) to carbonates under solvent-free conditions is described. Carbon dots containing carboxyl, hydroxyl, and amine groups were prepared by a microwave technique and employed together with KI, which showed exceptional catalytic activity in the cycloaddition of carbon dioxide with different epoxides. In addition, the catalyst was easily reusable and had stable recyclability. And the catalyst displayed outstanding catalytic performance due to the synergistic effect of carboxyl (–COOH), hydroxyl (–OH), and amine (–NH) groups. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) as new efficient catalysts have been developed for the Knoevenagel condensation reaction and the synthesis of cyclic carbonates under solvent‐free conditions. Six kinds of carbon dots with different numbers of amino groups were synthesized. The amine‐terminated carbon dot (NCDs‐1) was synthesized using arginine and ethylenediamine by a microwave technique, and its catalytic action was studied. NCDs‐1 with the highest numbers of amino groups was used as new metal‐free and effective heterogeneous catalysts to perform essential Knoevenagel condensation and cycloaddition reactions in solvent‐free conditions. 1H NMR was used to demonstrate the Knoevenagel condensation mechanism, in situ Fourier infrared spectroscopy was used to investigate CO2 cycloaddition and a catalytic mechanism was postulated. NCDs‐1 showed a yield of 96.3±1.5 % for Knoevenagel condensation of benzaldehyde and malononitrile. In addition, NCDs‐1/TBAB showed a yield of (97.0±1.0 %) of 4‐phenyl‐1,3‐dioxolan‐2‐one for styrene oxide at 100 °C and 0.1 MPa in 1.5 h. A simple and convenient method for catalytic reactions with amine‐terminated carbon dots was developed. [ABSTRACT FROM AUTHOR]

A fluorescent sensor array based on three kinds of carbon dots (CDs) were fabricated to discriminate hydroxybenzaldehyde and nitrobenzaldehyde isomers. Based on the Schiff base reaction, carbon dots with amino groups on the surface were designed. Fluorescence quenching of CDs occurred when hydroxybenzaldehyde and nitrobenzaldehyde isomers were combined with CDs. The sensor array showed different fluorescence patterns for each hydroxybenzaldehyde and nitrobenzaldehyde isomer in terms of fluorescence intensity change F/F0, which was further analyzed by principal component analysis (PCA). Finally, the fluorescent sensor array behaved well in differentiating and identifying hydroxybenzaldehyde and nitrobenzaldehyde isomers in aqueous solutions and distinguishing binary mixtures. [ABSTRACT FROM AUTHOR]

RNA editing in plant mitochondria and plastids converts specific nucleotides from cytidine (C) to uridine (U). These editing events differ among plant species and are relevant to developmental stages or are impacted by environmental conditions. Proteins of the MORF family are essential components of plant editosomes. One of the members, MORF9, is considered the core protein of the editing complex and is involved in the editing of most sites in chloroplasts. In this study, the phenotypes of a T-DNA insertion line with loss of MORF9 and of the genetic complementation line of Arabidopsis were analyzed, and the editing efficiencies of plastid RNAs in roots, rosette leaves, and flowers from the morf9 mutant and the wild-type (WT) control were compared by bulk-cDNA sequencing. The results showed that most of the known MORF9-associated plastid RNA editing events in rosette leaves and flowers were similarly reduced by morf9 mutation, with the exception that the editing rate of the sites ndhB-872 and psbF-65 declined in the leaves and that of ndhB-586 decreased only in the flowers. In the roots, however, the loss of MORF9 had a much lower effect on overall plastid RNA editing, with nine sites showing no significant editing efficiency change, including accD-794, ndhD-383, psbZ-50,ndhF-290, ndhD-878,matK-706, clpP1-559, rpoA-200, and ndhD-674, which were reduced in the other tissues. Furthermore, we found that during plant aging, MORF9 mRNA level, but not the protein level, was downregulated in senescent leaves. On the basis of these observations, we suggest that MORF9-mediated RNA editing is tissue-dependent and the resultant organelle proteomes are pertinent to the specific tissue functions. [ABSTRACT FROM AUTHOR]