The synthesis and fluorescence of a methoxy-phenyl substituted C_60-pyrrolidine derivative

A new 4-methoxyphenyl substituted C60-pyrrolidine derivative, C60(C10H13NO) (1), was prepared and its room-temperature fluorescence was studied. Its fluorescence intensity is three times stronger than that of C60. Its singlet energy was estimated to be 25 kJ/mol lower than that of C60. The fluorescence lifetime was determined to be 2.1+0.3 ns by using the frequency domain method. The fluorescence quenching by concentration and aromatic electron donor: N, N-dimethyl aniline (DMA) was investigated. Data show that its fluorescence could not be quenched by DMA.     

Synthesis and characterization of an acrylate polymer containing chlorine-1,3-dioxalane groups in side chains

Poly[2-（4-chlorophenyl）-1,3-dioxolan-4-yl]methyl acrylate,poly（CPhDMA）,was synthesized with radical polymerization process using 2,2′-azobisisobutyronitrile as radical initiator in 1,4-dioxane at 60℃.The structure of poly（CPhDMA） was confirmed by means of UV-Vis,FT-IR,¹H-NMR,and ¹³C-NMR spectral techniques.The molecular weight distribution values of the polymer were determined with gel permeation chromatography（GPC）.The number-average molecular weight（M_n）,weight-average molecular weight（M_W） and polydispersity index（PDI） values of poly（CPhDMA） were determined to be 10300,21600 and 2.097,respectively.The thermal degradation kinetics of the polymer was investigated by using TG/DTG-DTA and DSC analyses at different heating rates in dynamic nitrogen atmosphere.The apparent activation energy values obtained by Flynn-Wall-Ozawa and Friedman methods were found to be 91.68 and 85.23 kJ mol^-1,respectively,for thermal decomposition of poly（CPhDMA）.Also,the thermal degradation activation energy value of poly（CPhDMA） was calculated by using the Kissinger method based on the DTG,DTA and DSC data.Then the mechanism function of it was determined by master plots method.Finally,electrical and optical properties of poly（CPhDMA） were determined by four-point probe and UV-Vis techniques,respectively.     

Synthesis of Novel Phosphorylated Daidzein Derivatives and ESI Investigation on Their Non-Covalent Complexes with Lysozyme

Daidzein （7,4＇-dihydroxyisoflavone） was phosphorylated by a modified Atherton-Todd reaction. The structures of the five target product, were determined by X-ray, IR, NMR and ESI-MS. Electrospray ionization results show that in the gas phase all the phosphorylated daidzein derivatives could form non-covalent complexes with the protein lysozyme, while non-covalent complexes were not detected in the mixed solution of daidzein with lysozyme. Relative affinity of every non-covalent complex was obtained according to its different decomposition orifice voltage.     

Structure and Biological Activities of 2-（ 1,3-Dithiolan-2-ylidene）-1-phenyl-2- （ 1,2,4-triazol-1 -yl ） ethanone

In order to find leading compounds with an excellent fungicidal activity, the title compound 2-（ 1,3-dithiolan-2- yl-idene）-1-phenyl-2-（ 1,2,4-tfiazol-1-yl） ethanone was synthesized according to the biological isosterism and its structure was confirmed by means of IR, MS, ^1 H NMR and elemental analysis. The single crystal structure of the title compound was determined by X-ray diffraction. The preliminary biological test shows that the synthesized compound exhibits some biological activities.     

A novel real-time cell electronic analysis technology for the authentication and quality control of natural medicines

The study was designed to explore the potential applications of the real-time cell electronic analysis technology in the quality evaluation of natural medicines. The natural medicinal Flos Carthami was discussed as a methodological example and the specific time/dose-dependent cell response profiles （TCRPs） were produced by the real-time cell electronic analysis technology. The similarity and bioactivity were obtained by analyzing all TCRPs. Meanwhile, an HPLC method according to the Chinese Pharmacopeia （edition 2010） was used to evaluate the quality of Flos Carthami. The correlation was obtained by comparing the results produced by the two different approaches. By analyzing the data, five different samples ofFlos Carthami can produce remarkably similar TCRPs. The quality ofFlos Carthami was evaluated by both the HPLC and the TCRPs analysis-based approaches and similar results were obtained. The results suggest that the same natural medicine from different locations could produce similar TCRPs. By analyzing the TCRPs, the bioactivity and quality evaluation of natural medicines can be obtained. This technology is a physiologically relevant approach for the quality evaluation of natural medicines. The ultimate aim of our study is to establish a new standard for quality evaluation.     

Detection of OH Radical in the Photodissociation of p-Aminobenzoic Acid at 266 nm

Photodissociation of p-aminobenzoic acid at 266 nm was investigated by probing the nascent OH photoproduct employing the laser-induced fluorescence technique. It was found that the nascent OH radical was vibrationally cold and its rotational state distribution conformed to be a Boltzmann behavior, characterized by a rotational temperature of 1040±110 K. The rotational energy of OH was determined to be 8.78±0.84 kJ/mol. Between the two spinorbit states of OH, ^2Ⅱ3/2 and ^2Ⅱ1/2, the former was found to be preferentially populated. The distribution of the II（A＇） state for the A-doublet was dominant. Finally, a probable mechanism for the formation of OH produced from the photodissociation of p-aminobenzoic acid is discussed.     

Chelatometric dispersive liquid-liquid microextraction followed by capillary electrophoresis for the analysis of total and water soluble copper in Rhizoma coptidis

A new method for the analysis of copper and its speciation in Rhizoma coptidis was proposed using chelatometric dispersive liquid-liquid microextraction(cDLLME) followed by capillary electrophoresis. Dithizone was used as a chelating agent for extraction and carbon tetrachloride and ethanol were used as extraction and dispersive solvent,respectively.The calibration curve was linear in the range of 0.5- 20.0μg/mL with a correlation coefficient of 0.9990(n = 6) and the average recovery was in the range of 88.26%-94.44%.The method was successfully used to determine the total and water soluble copper in Rhizoma coptidis herbal medicine.The results suggested that it would be reasonable to setting the criterion of heavy metals in an herbal medicine according to the dosage forms.     

Cationic surfmers with benzyl groups: Synthesis and copolymerization with acrylamide

A series of cationic surfmers with benzyl groups（QARBCs）with different R groups on the benzene ring were synthesized and characterized by IR,¹H-NMR,¹³C-NMR.The aggregation of QARBCs was studied by the steady-state fluorescence technique.It turned out that QARBCs had surface activity and their critical micelle concentration（CMC）values varied in the range of 10^-2—10^-3mol/L with slight increase with temperature.The copolymerization of acrylamide（M₁）and QARBCs（M₂）was studied below and above CMC,their reactivity ratios were determined by the Finemann-Ross method.It was found that below CMC,copolymerization took place in a homogeneous system and reactivity ratios of acrylamide and QARBCs were less than 1;while above CMC,reactivity ratios of QARBCs were greater than 1.The copolymerization mechanism of QARBC was observed to be similar to that of micellar polymerization.QARBCs tended to homopolymerization,which gave rise to micro-blocky sequences in the polymer backbone.The Q and e values of QARBCs were calculated according to the Alfrey-Price equation by using r_1（AM）and r_2（qarBC）.Samples of poly（AM-co-QARBC） were prepared above and below CMC and their hydrophobic associations were studied by the steady-state fluorescence spectra and 2D NOESY spectra,and their critical associating concentrations（CAC）were estimated.The results showed that samples of poly（AM-co-QARBC）prepared above CMC had stronger hydrophobic association in aqueous solution than those prepared below CMC.     

A Novel Oligosaccharide from the Mucus of the Loach

A novel oligosaccharide was isolated and purified from the mucus of the loach, Misgurnus anguillicaudatus. Its was identified by several qualitative tests and characterized by elementary analysis,UV and IR spectrum. Its average molecular weight(Mw=1539.4) was determined by gel permeation chromatography. The major structural monomers of Misgurnus anguillicaudatus oligosaccharide were identified to be D-galactose and L-fucose by paper chromatography and gas chromatography.     

1，1－二氨基2，2－二硝基乙烯（DADE）的热化学性质、热行为和热分解机理

The constant-volume combustion energy, △cU （DADE, s, 298.15 K）, the thermal behavior, and kinetics and mechanism of the exothermic decomposition reaction of 1,1-diamino-2,2-dinitroethylene （DADE） have been investigated by a precise rotating bomb calorimeter, TG-DTG, DSC, rapid-scan fourier transform infrared （RSFT-IR） spectroscopy and T-jump/FTIR, respectively. The value of △cHm （DADE, s, 298.15 K） was determined as （-8518.09±4.59） j·g^-1. Its standard enthalpy of combustion, △cU （DADE, s, 298.15 K）, and standard enthalpy of formation, △fHm （DADE, s, 298.15 K） were calculated to be （-1254.00±0.68） and （- 103.98±0.73） kJ·mol^-1, respectively The kinetic parameters （the apparent activation energy Ea and pre-exponential factor A） of the first exothermic decomposition reaction in a temperature-programmed mode obtained by Kissinger＇s method and Ozawa＇s method, were Ek=344.35 kJ·mol^-1, AR= 1034.50 S^-1 and Eo=335.32 kJ·mol^-1, respectively. The critical temperatures of thermal explosion of DADE were 206.98 and 207.08 ℃ by different methods. Information was obtained on its thermolysis detected by RSFT-IR and T-jump/FTIR.     

Determination of Ascorbic Acid,Total Ascorbic Acid,and Dehydroascorbic Acid in Bee Pollen Using Hydrophilic Interaction Liquid Chromatography-Ultraviolet Detection

Ascorbic acid (AA) is one of the essential nutrients in bee pollen, however, it is unstable and likely to be oxidized. Generally, the oxidation form (dehydroascorbic acid (DHA)) is considered to have equivalent biological activity as the reduction form. Thus, determination of the total content of AA and DHA would be more accurate for the nutritional analysis of bee pollen. Here we present a simple, sensitive, and reliable method for the determination of AA, total ascorbic acids (TAA), and DHA in rape (Brassica campestris), lotus (Nelumbo nucifera), and camellia (Camellia japonica) bee pollen, which is based on ultrasonic extraction in metaphosphoric acid solution, and analysis using hydrophilic interaction liquid chromatography (HILIC)-ultraviolet detection. Analytical performance of the method was evaluated and validated, then the proposed method was successfully applied in twenty-one bee pollen samples. Results indicated that contents of AA were in the range of 17.54 to 94.01 µg/g, 66.01 to 111.66 µg/g, and 90.04 to 313.02 µg/g for rape, lotus, and camellia bee pollen, respectively. In addition, percentages of DHA in TAA showed good intra-species consistency, with values of 13.7%, 16.5%, and 7.6% in rape, lotus, and camellia bee pollen, respectively. This is the first report on the discriminative determination between AA and DHA in bee pollen matrices. The proposed method would be valuable for the nutritional analysis of bee pollen.     

Chemical Modification of Tryptophan Residues in Superoxide Dismutase from Camellia Pollen and Its Fluorescence Spectrum

The amino acid composition of the superoxide dismutase（SOD） from camellia pollen was measured and the tryptophan（Trp） residues were modified by using N-bromosuccinimide（NBS）. The results show that there are 21 Trp residues in an SOD molecule and seven of which are located on the surface of the enzyme. By researching the fluorescence spectra of the native SOD and the modified SOD, we have found that the emission wavelength of Trp is at 335 nm and the fluorescence intensity will decrease when the enzyme is modified. The results also show that potassium iodide（KI） can significantly quench the fluorescence of the native SOD, but it has a less pronounced effect on the modified enzyme. Glycerin as a surface activation reagent can stabilize the fluorescence of the modified enzyme.     

无花果叶超氧化物歧化酶的分离、纯化及性质研究

以我国山东无花果树(Brunswike, 原产法国Ficus carica)树叶为原料, 采用缓冲液抽提、硫酸铵分级、DEAE-Sepharose Fast Flow阴离子交换层析和Sephacryl S-100 HR分子筛层析分离纯化得到电泳纯CuZn-SOD, 并对其酶学性质进行研究.     

Purification and characterization of a superoxide dismutase from Panax ginseng

A superoxide dismutase (SOD) with the molecular weight of 31,079 has been purified as a homodimer from Panax ginseng by employing neutral pH buffer extraction, ammonium sulfate precipitation, isoelectric point precipitation and ion exchange methods. The enzyme's specific activity determined by an improved Marklund method was 9480.43 U/mg. Metal analysis showed that the SOD contained iron with the stoichiometry of 0.9 ± 0.3 Fe/subunit and exhibited high thermal stability (70°C) over the pH range from 4.0 to 9.0. Its maximum absorption wavelength was 278 nm and it was sensitive to hydrogen peroxide, trichloromethane‐ethanol and urea. These results indicate that the enzyme is an iron SOD. Copyright © 2010 John Wiley & Sons, Ltd.     

Maize pollen enzymes after two-dimensional polyacrylamide gel electrophoresis in the presence or absence of sodium dodecyl sulfate

Twelve enzymes from mature pollen grains of maize were separated by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). The separation in the second dimension was both in the presence and absence of sodium dodecyl sulfate (SDS). Ten of the investigated enzymes lost activity after separation in the presence of SDS, but those of esterases and acid phosphatase could be recovered. On the other hand, 2-D electrophoresis without SDS is suitable for the analysis of maize pollen pectinesterase, malate dehydrogenase, glutamic-oxalacetic transaminase, diaphorase, superoxide dismutase, and phosphoglucose isomerase. 1-D PAGE and isoelectric focusing (IEF) are sufficient to analyze glucose-6-phosphate dehydrogenase, alcohol dehydrogenase, shikimic dehydrogenase, and glutamate dehydrogenase. The possibility of applying 2-D electrophoresis for the analysis of enzymes from single stigma and stigma exudate is dicussed.     

A beta-glucosidase from Sclerotinia sclerotiorum: biochemical characterization and use in oligosaccharide synthesis

The filamentous fungus Sclerotinia sclerotiorum, grown on a xylose medium, was found to excrete one beta-glucosidase (beta-glu x). The enzyme was purified to apparent homogeneity by ammonium sulfate precipitation, gel filtration, anion-exchange chromatography, and high-performance liquid chromatography (HPLC) gel filtration chromatography. Its molecular mass was estimated to be 130 kDa by HPLC gel filtration and 60 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis, suggesting that beta-glu x may be a homodimer. For p-nitrophenyl beta-d-glucopyranoside hydrolysis, apparent Km and Vmax values were found to be 0.09 mM and 193 U/mg, respectively, while optimum temperature and pH were 55-60 degrees C and pH 5.0, respectively. beta-Glu x was strongly inhibited by Fe2+ and activated about 35% by Ca2+. beta-Glu x possesses strong transglucosylation activity in comparison with commercially available beta-glucosidases. The production rate of total glucooligosaccharides (GOSs) from 30% cellobiose at 50 degrees C and pH 5.0 for 6 h with 0.6 U/mL of enzyme preparation was 80 g/L. It reached 105 g/L under the same conditions when using cellobiose at 350 g/L (1.023 M). Finally, GOS structure was determined by mass spectrometry and 3C nuclear magnetic resonance spectroscopy.     

液相色谱-串联质谱法测定花粉中的链霉素和双氢链霉素

建立了花粉中链霉素（streptomycin,STR）与双氢链霉素（dihydrostreptomycin,DHS）的高效液相色谱-串联质谱（HPLC-MS/MS）检测方法。样品经提取液提取、三氯甲烷沉淀蛋白后,用C18固相萃取柱进行富集净化,采用HPLC-MS/MS对目标物进行定性确证和定量分析。在Protemix WCX-NP5色谱柱（100 mm×2.1 mm,5 μm）上以5%（v/v）甲酸、20 mmol/L醋酸铵和甲醇为流动相进行梯度洗脱分离;质谱采集模式为电喷雾正离子监测模式。链霉素和双氢链霉素的检出限（以信噪比（S/N）=3计）均为5 μg/kg,定量限（以S/N=10计）均为10 μg/kg;在10~200 μg/L的质量浓度范围内呈现良好的线性关系,相关系数（r）大于0.99。本底空白的松花粉、玉米花粉、茶花粉、葵花粉、油菜花粉、杂花粉等6种基质中10、20、50 μg/kg添加水平下的加标回收率范围为76.8%~100.3%,精密度范围为3.70%~12.6%。该方法无需使用对LC-MS联用仪容易造成污染的七氟正丁酸,且方法准确可靠,适用于大部分花粉基质的测定。     

多管漩涡混合-气相色谱-三重四极杆质谱测定油茶籽中18种多氯联苯

通过比较不同吸附剂的净化效果,建立了油茶籽中18种多氯联苯(PCBs)的气相色谱-三重四极杆质谱(GCQQQ-MS/MS)检测方法。油茶籽样品用乙腈提取,加氯化钠盐析,离心分层后提取液加无水硫酸镁、C18、N-丙基二乙胺(PSA)和多壁碳纳米管(NANO)进行多管漩涡振荡分散固相净化,GC-QQQ-MS/MS多反应监测(MRM)模式进行检测。结果表明,油茶籽中18种多氯联苯具有良好的线性关系,检出限为5μg/kg,平均回收率为109.2%,相对标准偏差为2.9%~6.2%(n=3)。方法应用于3个油茶主产省份油茶籽监测,48个油茶籽样品中18种多氯联苯均未检出。     

The Structures of Methylenebis(dichloroarsane) and Methylenebisarsonic Acid – A Combined Theoretical and Experimental Study

Methylenebisarsonic acid ( 3 ) was synthesized according to a published procedure. Its molecular structure and its spectroscopic characteristics were determined by single‐crystal X‐ray diffraction. The first intermediate, methylenebis(dichloroarsane) ( 1 ), was structurally and spectroscopically characterized as well. Both molecules were investigated on the B3LYP/6‐31+G(2d,p) level of theory and subsequent NBO analysis.     

A Superoxide Dismutase Purified from the Rhizome of <Emphasis Type="Italic">Curcuma aeruginosa</Emphasis> Roxb. as Inhibitor of Nitric Oxide Production in the Macrophage-like RAW 264.7 Cell Line

Superoxide dismutase (SOD, EC 1.15.1.1) is a metalloenzyme or antioxidant enzyme that catalyzes the disproportionation of the harmful superoxide anionic radical to hydrogen peroxide and molecular oxygen. Due to its antioxidative effects, SOD has long been applied in medicinal treatment, cosmetic, and other chemical industries. Fifteen Zingiberaceae plants were tested for SOD activity in their rhizome extracts. The crude homogenate and ammonium sulfate cut fraction of Curcuma aeruginosa were found to contain a significant level of SOD activity. The SOD enzyme was enriched 16.7-fold by sequential ammonium sulfate precipitation, diethylaminoethyl cellulose ion exchange, and Superdex 75 gel filtration column chromatography. An overall SOD yield of 2.51 % with a specific activity of 812.20 U/mg was obtained. The enriched SOD had an apparent MW of 31.5 kDa, as judged by sodium dodecyl sulfate polyacrylamide gel electrophoresis, and a pH and temperature optima of 4.0 and 50 °C. With nitroblue tetrazolium and riboflavin as substrates, the K _m values were 57.31 ± 0.012 and 1.51 ± 0.014 M, respectively, with corresponding V _max values of 333.7 ± 0.034 and 254.1 ± 0.022 μmol min⁻¹ mg protein⁻¹. This SOD likely belongs to the Fe- or Mn-SOD category due to the fact that it was insensitive to potassium cyanide or hydrogen peroxide inhibition, but was potentially weakly stimulated by hydrogen peroxide, and stimulated by Mn²⁺and Fe²⁺ ions. Moreover, this purified SOD also exhibited inhibitory effects on lipopolysaccharide-induced nitric oxide production in cultured mouse macrophage cell RAW 264.7 in a dose-dependent manner (IC₅₀ = 14.36 ± 0.15 μg protein/ml).