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Theoretical insights into elaborating and regulating excited state dynamics for the novel 6-cyano-2-(2 '-hydroxyphenyl)imidazo[1,2a]pyridine system in polar and nonpolar solvents
No full textGiven the importance of excited state relaxation in photochemical and photophysical behaviours, in this work, we mainly focus on the excited state dynamical behaviours for the novel 6-cyano-2-(2 '-hydroxyphenyl)imidazo[1,2a]pyridine (6-CN-HPIP) system in different aprotic solvents. We find the ultrafast excited state intramolecular proton transfer (ESIPT) behaviour without potential energy barrier for 6-CN-HPIP in nonpolar solvents. Furthermore, we also explore the excited state intramolecular hydrogen bonding interactions and confirm the hydrogen bond O-HN of 6-CN-HPIP should be strengthened based photo-excitation process. It provides the possibility of ESIPT process. And the charge redistribution resulting from photo-excitation around hydrogen bonding moieties further reveals the ESIPT tendency for 6-CN-HPIP molecule. It is worth mentioning that the increased electronic densities around proton-acceptor moiety play important roles in attracting hydrogen proton, which directly promotes ESIPT reaction. Via constructing potential energy curves, we clarify the ESIPT dynamical process for 6-CN-HPIP system and present a novel mechanism that nonpolar aprotic solvents facilitate ESIPT behaviour for 6-CN-HPIP. We hope that novel applications and developments could be promoted for 6-CH-HPIP and its derivatives through regulating and controlling ESIPT behaviours in future.
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Transient Receptor Potential V Channels Are Essential for Glucose Sensing by Aldolase and AMPK
No full textFructose-1,6-bisphosphate (FBP) aldolase links sensing of declining glucose availability to AMPK activation via the lysosomal pathway. However, how aldolase transmits lack of occupancy by FBP to AMPK activation remains unclear. Here, we show that FBP-unoccupied aldolase interacts with and inhibits endoplasmic reticulum (ER)-localized transient receptor potential channel subfamily V, inhibiting calcium release in low glucose. The decrease of calcium at contact sites between ER and lysosome renders the inhibited TRPV accessible to bind the lysosomal v-ATPase that then recruits AXIN:LKB1 to activate AMPK independently of AMP. Genetic depletion of TRPVs blocks glucose starvation-induced AMPK activation in cells and liver of mice, and in nematodes, indicative of physical requirement of TRPVs. Pharmacological inhibition of TRPVs activates AMPK and elevates NAD(+) levels in aged muscles, rejuvenating the animals' running capacity. Our study elucidates that TRPVs relay the FBP-free status of aldolase to the reconfiguration of v-ATPase, leading to AMPK activation in low glucose
液相色谱串联质谱法测定百日咳和百白破疫苗中百日咳杆菌气管细胞毒素
No full text百日咳杆菌气管细胞毒素(TCT)是一种引起百日咳及百日咳相关疫苗不良反应的毒性糖肽。尽管各国药典均规定了百日咳疫苗产品中TCT的含量限度,但均没有推荐TCT的含量测定方法。该研究发展了一种液相色谱-串联质谱法用于TCT的含量测定。实验优化了包括色谱柱类型和流动相组成在内的TCT色谱条件。虽然TCT在反相色谱模式和亲水作用色谱(HILIC)模式下均具有较好的保留,但HILIC模式与蛋白质沉淀的前处理方法兼容性更好,因此采用HILIC模式分离TCT。优化所得的方法具有较宽的线性范围(5.76~369 ng/L ),良好的重复性(峰面积的相对标准偏差不大于3.9%),各种基质中均有较好的回收率(96.4%~102.5%),且定量限是药典要求的TCT最高限量的1/1279 。将本方法用于共纯化百日咳疫苗、组分百日咳疫苗、共纯化无细胞百白破疫苗和组分无细胞百白破疫苗中TCT的检测,所有产品均未检出TCT,表明被检样品具有较好的工艺条件可避免TCT在产品中的残留
[open project Foundation of State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University]
No full textsynthesisesstructuresandantibacterialactivitiesofaseriesofrareearthnitrogenheterocycliccomplexes
No full textA series of rare earth metal complexes, Ln( IAA )(2)( phen )(2) center dot ( NO3) Ln=Ce(1), Gd( 2), Tb (3), Dy( 4 ), Ho (5). HIAA = indole acetic acid, phen = 1, 10-phenanthrolin
新型铋基金属有机框架的合成及其光催化产氢性能
No full text金属有机框架材料(MOFs)是由金属离子或团簇与多齿有机配体配位结合形成的一种结晶性材料.因其具有三维孔道结构,以及比表面积大、结构和功能可调变等优点,在气体的储存与分离、传感、药物传输和催化领域等方面具有广泛的应用.近年来,MOFs材料因其独特的结构和可调变性,在太阳能转化领域逐渐崭露头角,其中光催化水分解制氢作为一种可行的太阳能光化学转化方法,引起了人们的广泛关注.目前,MOFs材料用于光催化水分解制氢的研究已经取得了一定的进展,但在合成新型具有光催化性能的MOFs材料时,考虑到材料稳定性和能带位置的要求,在金属离子选择上往往受到限制.铋元素无毒且储量丰富,因其具有较高的价态和灵活的配位模式,在构建MOFs材料时常常会表现出独特的优势.然而,铋基MOFs对于合成条件十分敏感,Bi3+离子复杂的配位模式也使晶体结晶的过程难以调控.因此,铋基MOFs在合成方面具有一定的挑战.目前已报道的具有光催化活性的铋基MOFs材料十分有限,且能够实现光催化水还原的铋基MOFs材料还未有报道.本文利用1,3,6,8-四(4-羧基苯)芘(H4TBAPy)作为有机配体,合成了一种新型的三维铋基MOFs单晶材料(记为“Bi-TBAPy”),并对其结构、稳定性、光催化水还原性能及电荷转移机理进行了研究.单晶衍射结果表明,Bi-TBAPy中铋离子与来自四个不同配体的八个氧原子配位形成了立体的三维结构,二甲胺阳离子作为抗衡离子与铋离子配位使整个骨架保持电中性.实验测得的XRD结果与模拟的一致,表明Bi-TBAPy具有较高的相纯度.TGA以及XRD测试分析也证明了Bi-TBAPy具有良好的热稳定性和化学稳定性.结合UV/vis和莫特-肖特基的测试结果可知,Bi-TBAPy具有n型半导体性质,带隙宽度约为2.67 eV,导带和价带位置分别位于–0.25和2.42 eV,表明Bi-TBAPy在热力学上能够满足光催化水还原的要求.随后,以三乙醇胺为牺牲试剂考察了Bi-TBAPy的光催化产氢性能.研究发现助催化剂的种类对催化剂性能具有重要影响,担载2 wt%Pt时表现出最优的产氢速率,达140μmol h^–1 g^–1,其为目前报道的首个具有光催化水还原性能的铋基MOFs催化剂.长时间的光催化水还原反应测试可以持续稳定的进行,同时反应前后Bi-TBAPy的XRD也不发生变化,表明该材料具有很好的光化学稳定性.反应后样品的Bi 4f XPS谱图表明反应过程中有低价铋的生成,这说明配体受激发产生的光生电荷能够转移到Bi^3+上使其部分被还原.因此,该材料能够实现配体-金属电荷转移(LMCT)的过程,荧光光谱测试的结果证实了该过程有利于光生载流子的分离
Long noncoding RNA Linc00460 promotes breast cancer progression by regulating the miR-489-5p/FGF7/AKT axis
No full textPurpose: Evidence indicates that long noncoding RNAs (lncRNA) possess important roles in various cellular processes and that dysregulation of lncRNAs promotes tumor progression. However, the expression patterns and biological functions of many specific lncRNAs in breast cancer remain to be determined.
Methods: Quantitative real-time polymerase chain reaction was performed to detect Linc00460, miR-489-5p and FGF7 expression. Protein levels were determined using Western blot. MTT and colony formation assay were used to measure cell proliferation. Transwell assays were conducted to determine cell migration and invasion. Luciferase reporter assays were carried out to assess the interaction between miR-489-5p and Linc00460 or FGF7. Biotin pull-down assay was used to detect the direct interaction between miR-489-5p and Linc00460. In vivo experiments were performed to measure tumor formation and lung metastasis.
Results: We demonstrated that lncRNA Linc00460 was upregulated in breast cancer, and its expression level was positively associated with lymphatic metastasis and poor overall survival. Forced expression of Linc00460 increased, whereas Linc00460 silencing decreased, breast cancer cell viability, migration and invasion both in vitro and in vivo. Linc00460 was identified as a direct target of miR-489-5p, which further targeted FGF7 and exerted oncogenic functions in breast cancer. Mechanistically, Linc00460 served as a competing endogenous RNA of FGF-7 mRNA by sponging miR-489-5p, resulting in upregulated FGF7 expression and AKT activity. Notably, forced expression of miR-489-5p abrogated Linc00460-mediated oncogenic behavior and activation of the FGF7-AKT pathway in breast cancer cells.
Conclusion: We have demonstrated that Linc00460 promotes breast cancer progression partly through the miR-489-5p/FGF7/AKT axis