杂原子(Zr,Y)掺杂的铈基催化剂中氧物种与其催化CH_3SH分解的活性/稳定性之间的关系（英文）

铈基催化剂因其优异的储放氧能力被广泛地应用于多种催化反应.铈基材料作为催化剂在CH_3SH(甲硫醇)分解反应中的应用也因其产物简单、易处理而受到越来越多的关注.本课题组在前期研究中发现,纳米二氧化铈在CH_3SH催化分解反应中表现出较高的催化活性,然而催化剂却在很短时间内快速失活.为进一步提高铈基氧化物的稳定性,我们通过引入稀土元素对氧化铈催化剂进行改性,结果发现其稳定性明显提高;同时催化剂稳定性与氧空位数量有关,氧空位数量越多,催化剂越稳定.然而,目前关于氧空位对催化CH_3SH分解反应的具体作用,CH_3SH在铈基材料上的失活机理以及氧物种与催化行为之间的相互关系尚不清楚.因此,有必要进一步研究氧空位对提高催化稳定性的贡献并揭示催化行为与氧物种之间的相互关系.本文通过微波辅助柠檬酸络合法制备一系列杂原子(Zr,Y)掺杂的铈基催化剂CeO_2,Ce_(1-x)Z_rxO_2,Ce_(1-x)Y_xO_2-δ(x=0.25,0.50,0.75,1.00),通过考察锆、钇杂原子价态和离子半径对CH_3SH催化分解活性和稳定性的影响来探索铈基催化剂中氧空位的作用及氧物种与催化行为之间的关系.其中,氧物种与催化行为之间的关系可包括两类:(1)表面晶格氧与催化活性之间的关系;(2)体相晶格氧迁移与催化稳定性之间的关系.催化性能和表征结果表明,铈基氧化物中表面晶格氧对CH_3SH催化转化起着至关重要的作用.Ce_(0.75)Zr_(0.25)O_2在CH_3SH的催化分解中表现出更高的催化活性,这是由于Ce_(0.75)Zr_(0.25)O_2有更多的表面晶格氧、活性氧物种及良好的氧化还原性能.Ce_(0.75)Y_(0.25)O_2-δ也表现出更好的催化稳定性,这是由于催化剂中有更多的氧空位,它们会促进体相晶格氧迁移到催化剂表面以补充表面晶格氧.此外,Ce与杂原子之间化学价差极大地影响着表面晶格氧含量以及催化剂中体相氧的迁移率,进而影响铈基催化剂的活性和稳定性.

LIWRKY39 is involved in thermotolerance by activating LIMBF1c and interacting with LICaM3 in lily(Lilium longiflorum)

WRKY transcription factors(TFs)are of great importance in plant responses to different abiotic stresses.However,research on their roles in the regulation of thermotolerance remains limited.Here,we investigated the function of LlWRKY39 in the thermotolerance of lily(Lilium longiflorum‘white heaven’).According to multiple alignment analyses,LIWRKY39 is in the WRKY IId subclass and contains a potential calmodulin(CaM)-binding domain.Further analysis has shown that LlCaM3 interacts with LlWRKY39 by binding to its CaM-binding domain,and this interaction depends on Ca^(2).LIWRKY39 was induced by heat stress(HS),and the LIWRKY39-GFP fusion protein was detected in the nucleus.The thermotolerance of lily and Arabidopsis was increased with the ectopic overexpression of LlWRKY39.The expression of heat-related genes AtHSFA1,AtHSFA2,AtMBF1c,AtGolS1,AtDREB2A,AtWRKY39,and AtHSP101 was significantly elevated in transgenic Arabidopsis lines,which might have promoted an increase in thermotolerance.Then,the promoter of LlMBF1c was isolated from lily,and LlWRKY39 was found to bind to the conserved W-box element in its promoter to activate its activity,suggesting that LlWRKY39 is an upstream regulator of LlMBF1c.In addition,a dual-luciferase reporter assay showed that via protein interaction,LlCaM3 negatively affected LlWRKY39 in the transcriptional activation of LlMBF1c,which might be an important feedback regulation pathway to balance the LlWRKY39-mediated heat stress response(HSR).Collectively,these results imply that LlWRKY39 might participate in the HSR as an important regulator through Ca^(2+)-CaM and multiprotein bridging factor pathways.

Crystallization and Characterization of a New Fluorescent Molecule Based on Schiff Base

In this analysis, the single crystal of schiff base has been synthesized and the purity of material has been increased by repeated recrystallization process. Single crystal was grown by adopting the method growing in a slow evaporation solution using ethanol as solvent at room temperature. A new fluorescent molecule based on Schiff base has been synthesised and its binding properties investigated by fluorescence spectroscopy to show that it can selectively bind Cu2+ with fluorescence quenching.

Synthesis and X-Ray Structure of New Anticancer Nucleosides Based on 1-((2-Hydroxyethoxy)methyl)-5-(phenylthio)-1H-1,2,4-triazole-3-carboxamide

A pair of new anticancer nucleosides based on 1,2,4-triazole nucleosides and 1-((2-hydroxyethoxy) methyl)-5-(phenylthio)-1H-1,2,4-triazole-3-carboxamide have been synthesized, and have given the corresponding products in excellent yields. Its structures and conformations were confirmed by single crystal X-ray diffraction.

Synthesis and X-Ray Structure of Important Anticancer Nucleosides Intermediate (2<i>R</i>,3<i>S</i>,4<i>S</i>,5<i>R</i>)-2-(acetoxymethyl)-5- (3-bromo-5-(methoxycarbonyl)- 1<i>H</i>-1,2,4-triazol-1-yl)tetrahydrofuran- 3,4-diyl Diacetate

An important anticancer nucleosides intermediate (2R,3S,4S,5R)-2-(acetoxymethyl)-5-(3-bromo-5-(methoxycar-bonyl)-1H-1,2,4-triazol-1-yl)tetrahydrofuran-3,4-diyl diacetate was synthesized by directly coupling the bromotriazole with the protected ribose sugar, and have given the corresponding product in moderate yield. Its structure and conformation were confirmed by single crystal X-ray diffraction.

Overexpression of lily LlWRKY22 enhances multiple abiotic stress tolerances in transgenic Arabidopsis

In our previous study,a heat-induced differentially expressed WRKY-IIe gene LlWRKY22 is isolated from lily(Lilium longiflorum),which acts as a positive role in thermotolerance,but whether it is involved in other stress responses is unknown.Here,the expression of LlWRKY22 was indicated to be positively influenced by heat,salt,or mannitol treatments,and its promoter activity was also enhanced after heat,salt,or mannitol treatments.In addition,LlWRKY22 responded to ABA treatment,which activated its expression and also increased the promoter activity.Overexpression of LlWRKY22 in Arabidopsis contributed to growth defects and early flowering.Simultaneously,compared with the wild type,the ABA sensitivity in transgenic lines was increased in both the germination stage and late growth stage.Further analysis showed that LlWRKY22 overexpression elevated the thermotolerance of transgenic plants and induced the expression of AtDREB2A,AtDREB2B,AtDREB2C,and AtJUB1.The salt and mannitol tolerances of the overexpression lines were also improved.Overall,our results illustrated that LlWRKY22 is affected by heat,salt,and osmotic stresses,and positively regulates heat,salt,and osmotic tolerances,which reveals that it acts as a generalist character responding to different abiotic stresses.And further to that,the regulatory pathway of LlWRKY22 also involves in ABA signaling.

Cytological and Molecular Characteristics of Pollen Abortion in Lily with Dysplastic Tapetum

Lily was grown worldwide as a fresh cutting flower because of its colorful petals, but its anther contained a large number of pollen grains that cause serious pollen contamination, however, pollen abortion can effectively reduce the level of pollen pollution. Our analysis aims to use cytological observation to detect the critical stage when pollen abortion occurs and to provide comprehensive gene expression information at the transcriptional level. The result showed that pollen abortion in ‘Little Kiss’ began at the mononuclear stage and the callose that covers the microspores failed to degenerate when young pollens were released from the tetrads. In addition, compared with the normally developed one,the tapetum of ‘Little Kiss’ degraded in advance while the degradation of callose was delayed. Furthermore, 103 differentially expressed genes(DEGs) related to the advance degeneration of tapetum cells and callose were found in the expression levels, including 22 transcription factors(TFs). In particular, two β-glucanase genes(endo-1,3(4)-β-glucanase, exo-β-glucanase) responsible for callose degeneration were significantly down-regulated. These results suggested that pollen abortion may occur at mononuclear stage and that early degeneration of tapetum cells resulted in a significant down-regulation of β-glucanase genes. As a result, the callose to cover microspores impedes the formation of pollen walls, which may possibly lead to pollen abortion.