Aptamer functionalized magnetic graphene oxide nanocomposites for highly selective capture of histones

The binding coverage of aptamer was an important restricted factor for aptamer‐based affinity enrichment strategy for capturing target molecules. Herein, we designed and prepared aptamer functionalized graphene oxide based nanocomposites (GO/NH₂‐NTA/Fe₃O₄/PEI/Au), and the coverage density of aptamer was high to 33.1 nmol/mg. The high aptamer coverage density was contributed to the large surface area of graphene oxide. The successive modification of Nα,Nα‐Bis(carboxymethyl)‐L‐lysine, magnetic nanoparticles, polyethylenimine, and Au nanoparticles ensured the histone purification with fast speed and high purity. Histones could be captured rapidly and specifically from nucleoproteins by our aptamer based purification strategy, while traditional acid‐extraction could not specifically enrich histones. Compared with traditional acid‐extraction method, rapid and efficient discovery of histones and their post‐translational modifications, such as several kinds of methylation at H3.1K9 and H3.1K27, were achieved confidently. It demonstrated that our aptamer functionalized magnetic graphene oxide nanocomposites have a great potential for histone analysis.     

基于双重碳氢活化的γ,δ-不饱和酰胺与炔烃的脱氢环化反应

吡啶酮是一类重要的含氮杂环骨架,广泛存在于天然产物和药物分子中,是重要的化学转化中间体,其合成与修饰是现代医药学及化学领域的研究热点之一。杂环母核的官能团化修饰是该类化合物较为常见的衍生方式,但要求特定位点的反应基团预组装。相较而言,两个片段分子的直接偶联环化,是更为直接且具备较高实用性的合成类似杂环分子库的方式。近年来,过渡金属催化的丙烯酰胺与炔烃的氧化偶联制备吡啶酮类化合物取得了长足进展,关键活化步骤为过金属催化剂对酰胺β位sp2碳氢键的活化。然而,通过对更加易得的烷基酰胺进行sp3碳氢键活化制备杂环骨架依然具有较高的挑战性。其原因主要在于较低的α-酸性使得酰胺的脱氢反应变得异常困难。本课题组最近报道了温和条件下,铱催化的酰胺、酸及酮的空气脱氢反应。反应中产生的烯丙基-铱中间体被认为提高了酰胺的α-酸性,从而加速了脱氢过程。在此基础上,我们报道一种铑(Ⅲ)催化的γ,δ-不饱和酰胺与炔烃类化合物的脱氢环化新方法,制备一系列多取代的吡啶酮类化合物。催化循环历经酰胺导向铑(Ⅲ)对底物β位点的sp3碳氢活化,进而脱氢生成共轭的双烯酰胺中间体,随后酰胺基团再次导向铑(Ⅲ)对β位的sp2碳氢活化,进而与炔烃进行插入,环化获得吡啶酮。该反应对各种官能团具有较好的容忍性。γ-烯基结构不但促进第一步的酰胺脱氢,而且是杂环产物后修饰的重要位点。机理实验表明双烯酰胺的确为反应中间体之一。核磁实验显示酰胺脱氢迅速,而控制实验则表明炔烃的插入过程的选择性与其电性有密切的关系,有可能参与了该反应的速控步。     

元素周期表实物展窗:元素化学性质的形象化展示

以展示元素单质、化合物和矿物样品为形式制作的元素周期表实物展窗能够形象化地展示各种元素的化学特性。元素周期表实物展窗将实物样品展示度与样品背后的化学内涵相结合,可以展示元素和化学学科的风貌。     

Design,Synthesis and Antifungal Activity of Benzofuran and Its Analogues

Benzofuran has antifungal activity as the inhibitor of N‐myristoyltransferase. Twenty‐nine novel benzofuran‐semicarbazide hybrids were designed and synthesized by principle of drug combinationatory. On this basis, the benzofuran ring was simplified to a resorcinol structure, and sixteen novel 1,3‐dialkoxybenzene‐semicarbazide hybrids were designed and synthesized. All structures of the target compounds were characterized by HRMS and NMR. The in vitro antifungal activity of target compounds was evaluated using the microdilution broth method against eight strains of pathogenic fungi with fluconazole as positive control. According to the results of the target compounds, structure‐activity relationship (SAR) is summarized. The inhibitory activity against the tested strains of simplified compounds ( K01 — K16 ) has different levels improvement compared with compounds Z01 — Z29 . K01 — K16 showed significant antifungal activities against A. fumigatus, C. kruseii, and sensitive C. albicans 5314. Notably, compounds Z20 , Z22 , K10 , K11 and K16 also displayed different activities against two fluconazole‐resistance strains that were isolated from AIDS patients. The minimal inhibitory concentration (MIC) values against fluconazole‐resistant strains were in the range of 2—8 μg/mL and 4—32μg/mL, respectively. Furthermore, molecular docking was performed to investigate the binding affinities and interaction modes between the target compound and N‐myristoyltransferase.     

微型通风橱

简单介绍设计的微型通风橱在处理有毒气体上的应用,使有毒气体参与或产生的反应更环保。     

Carbon nanotube@ZIF–derived Fe-N-doped carbon electrocatalysts for oxygen reduction and evolution reactions

Journal of Solid State Electrochemistry - Iron-nitrogen co-doped hierarchical porous carbon (Fe-N-HPC) was synthesized through the carbonization of carbon nanotube@ZIF composite. It was found that...     

Comparative analysis of nucleosides,nucleobases, and amino acids in different parts of Angelicae Sinensis Radix by ultra high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry

A rapid and sensitive ultra high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry method was established and employed to determine 21 nucleosides, nucleobases, and amino acids in 60 samples from different parts of Angelicae Sinensis Radix. The established methods were validated by good linearity (r² > 0.9937), limits of detection (0.12–77.75 ng/mL), limits of quantitation (0.31–272.13 ng/mL), intra‐ and interday precisions (RSD ≤ 4.84%, RSD ≤ 6.26%), stability (RSD ≤ 5.92%), repeatability (RSD ≤ 7.14%), recovery (91.4–103.4%), and matrix effects (0.92–1.03). Chemical comparative analysis revealed that the content of total analytes in four parts of Angelicae Sinensis Radix were different, and exhibited the order: Head (14.89 mg/g) > Body (10.15 mg/g) > All (8.22 mg/g) > Tail (6.23 mg/g). Principal component analysis showed that the samples could be classified into four groups in accord with four different parts of Angelicae Sinensis Radix. The results could provide a scientific basis and reference for the quality control of Angelicae Sinensis Radix, and may be conducive to further research on the pharmacological activities of Angelicae Sinensis Radix.     

Nine components pharmacokinetic study of rat plasma after oral administration raw and prepared Semen Cassiae in normal and acute liver injury rats

In China, Semen Cassiae has long been used to protect liver, brighten eyes, and relieve constipation. Prepared Semen Cassiae is produced from raw Semen Cassiae by processing, the two forms of Semen Cassiae have different clinical applications. Pathological state is an important factor affecting the efficacy of drugs, the pharmacokinetic behavior of drugs could be significantly changed when people or animal were under different pathological state. To clarify the effect of processing mechanism and pathological state for pharmacokinetic behavior, the pharmacokinetics of nine components of raw and prepared Semen Cassiae under normal and acute liver injury rats were examined. The results showed that the bimodal phenomenon appeared on the plasma concentration‐time profiles of obtusin, emodin, chrysophanol, aloe emodin and rhein. The T_max of aurantio‐obtusin, obtusin, chrysoobtusin, emodin, chrysophanol, aloe emodin, physcion in normal groups administrated prepared Semen Cassiae were shorter than those administrated raw Semen Cassiae. For the AUC_0–t, aurantio‐obtusin, obtusin, chrysoobtusin, chrysophanol, aloe emodin and physcione in model groups administrated prepared Semen Cassiae were significantly higher than other groups, unlike above components, rhein had poor absorption in model groups. The study would be useful for further studies on pharmacokinetics and clinical application of raw and prepared Semen Cassiae.     

Solid acids assisted matrix solid‐phase dispersion microextraction of alkaloids by capillary electrophoresis coupled with quadrupole time‐of‐flight mass spectrometry

The quantification of three alkaloids is important because quantitative study is a means of assessing the reliability of the experimental method, and three alkaloids of peimine, peiminine, and peimisine are main active ingredients in Chinese Pharmacopoeia 2015. An effective method based on the matrix solid‐phase dispersion microextraction was developed for the extraction of alkaloid compounds in Fritillariae Thunbergii Bulbus. Target analytes were analyzed by capillary electrophoresis coupled with quadrupole time‐of‐flight mass spectrometry. The optimized experimental condition was that 50 mg Fritillariae Thunbergii Bulbus was blended homogeneously with 10 mg citric acid for 5 min. Two hundred microliters of water acidized by 1 mol/L hydrochloric acid (pH = 4.5) was selected to elute tested alkaloids. The results demonstrated that the investigated method had low limits of detection (1.32–1.59 ng/mL), good recoveries (86.63–98.12%), and reproducibility (relative standard deviations of peak areas < 0.87%). The proposed matrix solid‐phase dispersion microextraction coupled with capillary electrophoresis combined with quadrupole time‐of‐flight mass spectrometry was successfully applied for the extraction of alkaloids in plants.