Kinetic spectrophotometric determination of vanadium in steels based on the catalytic oxidation of thionine by potassium bromate

A sensitive and selective kinetic spectrophotometric method for the determination of V（V） was developed based on the catalytic oxidation of thionine by KBIO3 in 0.6 mol·L^-1 HaPO4 medium. The linear calibration range and detection limit at 25℃ were 0-0.5 μg·mL^-1 and 0.01 μg·mL^-1, respectively. In the presence of NaF and urea, most of the common ions did not interfere with the determination of V（V）. The proposed method was applied for the determination of vanadium in steels and satisfactory results were obtained.

A Novel Amperometric Nitric Oxide Sensor Based on Polythionine/Nation Modified Glassy Carbon Electrode

A novel amperometric sensor for the determination of nitric oxide was developed by coating polythionine / nation on a glassy carbon electrode. This sensor exhibited a great enhancement to the oxidation of nitric oxide. The oxidation peak currents were linear to the concentration of nitric oxide over the wide range from 3.6×10^-7 to 6.8×10^-5 mol·L^-1, and the detection limit was 7.2×10^-8 mol·L^-1. Experimental results showed that this nitric oxide sensor possessed excellent selectivity and longer stability. NO releasing from rat kidney was monitored by this sensor.

The Electrochemical Properties of Thionine Adsorbed Monolayer on Gold Electrode

A gold electrode modified with adsorbed thionine monolayer was investigated with ac impedance and cyclic voltammetry method. It was found there were some different redox properties for the adsorbed thionine depended on the different potential scanning rate. At the slower potential scanning rate (10 mV? s?1), the dimer of thionine appeared and possessed the catalytic activity for the oxidation of ascorbic acid. The underpotential deposition (UPD) and the bulk deposition of Cu2+ were also employed to investigate the monolayer of adsorbed thionine.

Photocatalytic Degradation of Methyl Thionine Chloride in Aqueous Solution over Nanometer (CdS/TiO_2)/MCM-41

（ CdS/ TiO2 ）/ MCM-41 loaded nanometer photocatalyst was prepared by the sol-gel method and dipping process, the photocatalytic degradation of methyl thionine chloride in water was investigated by using the photocatalyst. The experimental results show that the optimum concentration of CdS over TiO2 was 3% （ molar ratio ）, the photocatalytic activity was enhanced when making TiO2 the anatase ptase with a rise of the roasting temperature, and the carrier, mesoporous molecular sieve MCM-41, was beneficial to improving the photocatalytic activity of TiO2 for photocatalytic degradation of methyl thionine chloride. The morphology and the crystalline phase of the photocatalyst were discussed by means of XRD and SEM techniques, and the reaction mechanism of catalytic properties was also discussed.

A New Thionine Modified Electrode by Anchorage to Bi-(2-aminoethyl)-aminodithiocarboxyl Acid Self-assembled Monolayers through Coordination with Cu^(2+#)

A new method for preparing chemically modified gold electrode by anchoring thionine to self-assembled bi - (2 -aminoethyl) -aminodithiocarboxyl acid(BANTC) monolayers through coordination with Cu2+ is described. This thionine modified electrode exhibits two-new redox couples.Two protons were involved in the electrochemical process undergone by the couple I in the pH range of 5.0-10.0. The apparent surface electron transfer rate constant is about 0.050s-1.

Drug-DNA Interaction: A Theoretical Study of the Stability of CP-DNA Binding with Thionine

The recent study on binding of small molecules to double stranded DNA suggested that the intercalation of a tricyclic heteroaromatic molecule, thionine, with natural DNA provided thermal stabilization to the complex. In the present study, we reported theoretical analysis of thionine binding with Clostridium perfringenes DNA duplex (CP-DNA) by using an amended Zimm and Bragg theory, to explain the melting behaviour and heat capacity of CP-DNA with and without thionine binding. The experimental models of Paul et al. (2010) have been used for the study. The sharpness of transition has been examined in terms of half width and sensitivity parameter (?H/σ). The results of theoretical approach suggested that the various parameters such as transition profile, sharpness of the transition, heat capacity curve and half widths are in good agreement with the experimental measurements for binding of thionine. Therefore, the proposed theoretical analysis may be useful in order to understand interaction of small molecules to DNA that may be applied in the process of drug development and for designing more potential DNA binding therapeutic molecules.

人参thionins的克隆、原核表达和活性研究

抗菌肽在人参的生长过程中发挥了抑菌抗逆等重要作用。通过研究人参硫堇蛋白(Thionins)的抗菌活性,为未来进行大规模生产和生物农药研究奠定基础。分析人参thionins序列,构建原核表达质粒,诱导蛋白表达,对包涵体进行亲和纯化,使用纸片扩散法和质膜通透性实验检测纯化蛋白的抗菌活性。人参thionins长度为228 bp,编码75个氨基酸,选取其成熟肽区域(29-75 aa)进行后续的表达和纯化。成功构建了原核表达质粒pGEX-4T1-thionins,在大肠杆菌BL21中获得目的蛋白的高效表达,通过包涵体纯化获得目的蛋白,并进行复性和浓缩。人参硫堇蛋白在3和9μmol/L的浓度下,对黑斑病菌丝的生长抑制率分别为36.0%和51.1%,对黑斑孢子的半数抑制浓度为0.87μmol/L。人参硫堇蛋白具有显著抑制人参黑斑病真菌的活性的作用。

大麦Thionin-like基因家族基因表达谱分析

类硫素基因Thil(Thionin-like)在植物防御系统中具有抗病原微生物的活性,然而对它的功能却不清楚。通过对Thil基因家族在大麦中的序列组成及基因结构、染色体分布、蛋白保守结构域、系统进化树、基因启动子元件、亚细胞定位和表达谱分析,为其生物学功能研究提供借鉴。共鉴定出7个大麦Thil基因,这些基因分布于1、2、4、5和6号染色体上;基因结构分析均表明,除Thil4存在一定的差异外,其它家族成员序列都较为保守;通过系统进化树可以看出大麦Thil基因分为4个亚家族;表达谱分析结果显示,在大麦不同组织中,Thil基因的表达量有所不同,总体来看,Thil基因在根和种子中的表达量极低,在幼叶中表达量最高。Thil家族不同成员之间的蛋白亚细胞定位结果也不一样,Thil1和Thil2主要定位于细胞膜、细胞核和细胞质上,Thil3和Thil7定位于细胞膜上,Thil6定位于叶绿体。Thil基因与植物的保护和防御机制有关,在幼叶中能够激发植物保护机制的元件响应最多,荧光定量PCR实验结果显示,Thil基因在幼叶中的表达量最高,在亚细胞定位中可以发现不同的成员之间在进化过程中分别参与了不同的发育学过程。

受光抑制的大麦叶片特导Thionin的cDNA序列

Thionin(硫堇)是一类小分子量多肽.这种蛋白最早在小麦面粉中发现,随后在其它禾谷类作物和一些双子叶植物如十字花科的Crambe abyssinica的种子中也发现了类似的蛋白.1987年在大麦叶片、1993年在烟草花器中又发现了叶片和花特异的thionin.Thionin有以下几个特点:分子量小约500D,热稳定性高,带正电荷,巯基含量高.

Determination of carcinoembryonic antigen using a novel amperometric enzyme-electrode based on layer-by-layer assembly of gold nanoparticles and thionine

Electrochemical sensing of carcinoembryonic antigen(CEA)on a gold electrode modified by the se- quential incorporation of the mediator,thionine(Thi),and gold nanoparticles(nano-Au),through co- valent linkage and electrostatic interactions onto a self-assembled monolayer configuration is de- scribed in this paper.The enzyme,horseradish peroxidase(HRP),was employed to block the possible remaining active sites of the nano-Au monolayer,avoid the non-specific adsorption,instead of bovine serum albumin(BSA),and amplify the response of the antigen-antibody reaction.Electrochemical ex- periments indicated highly efficient electron transfer by the imbedded Thi mediator and adsorbed nano-Au.The HRP kept its activity after immobilization,and the studied electrode showed sensitive response to CEA and high stability during a long period of storage.The working range for the system was 2.5 to 80.0 ng/mL with a detection limit of 0.90 ng/mL.The model membrane system in this work is a potential biosensor for mimicking the other immunosensor and enzyme sensor.

Direct Electrochemical Detection of Oligonucleotide Hybridization on Poly（thionine） Film

In this work, the application of a conducting polymer, poly（thionine）, modified electrode as matrix to DNA immobilization as well as transducer to label-free DNA hybridization detection was introduced. The electropolymerization of thionine onto electrode surface was carried out by a simple two-step method, which involved a preanodization of glassy carbon electrode at a constant positive potential in thionine solution following cyclic voltammetry scans in the solution. Electrochemical detection was performed by differential pulse voltammetry in the electroactivity potential domain of poly（thionine）. The resulting poly（thionine） modified electrode showed a good stability and electroactivity in aqueous media during a near neutral pH range. Additionally, the pendant amino groups on the poly（thionine） chains enabled poly（thionine） modified electrode to immobilize phosphate group terminated DNA probe via covalent linkage. Hybridization process induced a clear decrease in poly（thionine） redox current, which was corresponding to the decrease in poly（thionine） electroactivity after double stranded DNA was formed on the polymer film. The detection limit of this electrochemical DNA hybridization sensor was 1.0 × 10^-10mol/L. Compared with complementary sequence, the hybridization signal values of 1-base mismatched and 3-base mismatched samples were 63.9% and 9.2%, respectively.

A novel strategy for immobilization of thionine based on calcium carbonate-gold nanoparticles inorganic hybrid composite and its application in hydrogen peroxide sensor

A novel strategy for efficient immobilization of electroactive Thionine(Th)on the gold(Au)electrode surface based on calcium carbonate-gold nanoparticles(CaCO3-AuNPs)inorganic hybrid composite was proposed and conducted by the strong electrostatic interaction between positively charged Th and negatively charged CaCO3-AuNPs composite.The hybrid composite was obtained by the adsorption of AuNPs onto the surface of CaCO3 microspheres through electrostatic interaction.Due to the microporous architecture,large surface area,and good biocompatibility of CaCO3-AuNPs composite,the amount and stability of the immobilized Th were highly strengthened.The application of the resulting Th modified electrode in the hydrogen peroxide(H2O2)sensor was also investigated.It exhibited rapid response to H2O2 within 3 s.The linear calibration ranged from 8.00×107to 1.06×10 -3mol/L with a detection limit of 2.00×10 -7mol/L.

Langmuir Aggregation of Thionin in Nucleic Acids and Its Application

The microsurface adsorption-spectral correction (MSASC) technique has been described. The formation of the double electrostatic films in nucleic acids causes the monolayer aggregation of stain molecules. The interaction of thionin (TN) with nucleic acids, ctD-NA, sDNA and yRNA, has been investigated at pH 7.8. Results show that the binding ratios of TN to ctDNA-P, sDNA-P and yR-NA-P are 1.27, 1.30 and 1.40, respectively, the binding constants of the aggregates are 2.8 · 104, 9.10 · 104 and 6.49 · 103 and their molar absorptivities are 1.04 · 104, 1.25 · 104 and · 104 L· mol?1, cm?1 at 630 nm. The aggregation may be applied to the spectrophotometric detection of nucleic acids samples.

Kinetics of Reduction of Thionine with Ribose and the Structural Properties of the Dye at Different pH Using DFT Method

The reaction between the thionine （Th） and the ribose was observed spectrophotometrically and changes in absorbance of Th were recorded at variable concentration of dye, reductant and pH. A pseudo first order rate of reaction was found to establish the reduction kinetics of the dye, studied at a pH range of 0.34 to 12.8. Absorption spectrum of Th at different pH, with ribose showed a pH （12.8） dependent introversion. The reduction most probably took place with enediol intermediate of the sugar at high pH. A full geometry optimization of predominant species of Th namely, mono-deprotonated, di-deprotonated Th, and LTh （leuco thionine） respectively, at low and high pH, was performed at B3LYP level of theory. The data obtained from the energy minimization were in excellent agreement with other experimental and theoretical observations. The calculated enthalpies of formation for both reduction reactions （mono-deprotonated Th＋H＋→leucothionine and di-deprotonated Th＋2H＋→leucothionine） provided evidences for maximum reduction of the dye at high pH.

Thionine sensitized areobic photooxidation of thiourea in acidic medium

An investigation of the thionine sensitized aerobic photooxidation of thiourea was observed spectrophotometrically at a wavelength of 598 nm.Articles reported two types of reactions which generally occur in the presence of oxygen:1)Singlet oxygen,produced by dye sensitization due to the hydrolysis that reacts with thiourea to form oxidative products like urea and other sulfur-containing fragments and 2)bleaching of dye,which leads to the reduction.The rate of reaction in all studied parameters followed first order kinetics with respect to maximum absorption of the dye in the visible band region.Reaction kinetics was significantly dependent upon the medium and the reaction accelerated more rapidly at low pH.A direct relation was exhibited between the thiourea concentration and dye sensitizer,which was not pragmatic with the concentration of dye.The reaction was effected by the temperature,and the values of energy parameters suggested that the energy of activation was low while the entropy of activation increases with the rise in temperature,which indicated a highly solvated state of intermediate complex.Lower value of ΔH* and ΔG*at elevated temperature showed that free energy is the driving force for the completion of reaction.A mechanism based on the above findings has been suggested.

小麦类硫素基因家族鉴定及表达分析

类硫素(thionin-like,Thil)在植物应对病原微生物侵染的防御反应中具有重要生物学功能。本研究通过拟南芥(Arabidopsis thaliana)的Thil基因序列,利用同源搜寻及生物信息学方法初步鉴定到普通小麦(Triticum aestivum L.)的Thil基因家族。结果表明,Thil基因家族在普通小麦中包含26个成员。基因序列结构分析得到Thil家族存在保守的基序结构,家族各成员基因编码的蛋白质序列包含79~196个氨基酸,大部分蛋白质的氨基酸数量少于140,其中20个蛋白质包含信号肽。顺式作用元件预测分析结果显示,小麦Thil基因的启动子调控元件受到脱落酸等逆境胁迫相应激素的影响,同时基因表达谱呈现出受到病原菌胁迫诱导后的多样性表达。通过进一步qRT-PCR验证分析表明,普通小麦的TaThil-4A、TaThil-4B和TaThil-4D等3个基因在叶锈病菌早期侵染中被诱导表达。本研究结果可为小麦抗病育种及Thil基因家族的功能鉴定与应用提供参考。

肝性脑病脑组织病理形态观察

我们于九十年代初起不加选择收集肝硬变死亡者肝、脑组织,对照临床表现和血液检查,探讨肝性脑病(HE)的病理基础,共观察70例,现总结报道如下。 资料和方法 一、一般资料 70例患者的临床表现和实验室检查均符合肝硬变诊断,肝组织病理切片检查,均可见典型肝硬变的病理特点。男51例,女19例,年龄7岁～71岁,平均48.7岁。临床显示HE,死于肝衰者41例,

溶液pH对硫堇与DNA相互作用方式的影响

用电化学和光谱方法研究了溶液pH对硫堇(TH)与小牛胸腺脱氧核糖核酸(CT-DNA)相互作用方式的影响。电化学测量结果表明,在pH 7.2的磷酸盐缓冲溶液中,TH与CT-DNA之间的作用方式以嵌入结合为主,在pH6.5的磷酸盐缓冲溶液中,TH与CT-DNA之间的作用方式既存在嵌入结合也存在静电作用。荧光光谱测量结果表明,TH与DNA结合后其荧光发生猝灭,通过Stern-Volmer方程计算得到pH 6.5时TH-DNA体系的猝灭常数高于pH 7.2时的值,表明在pH 6.5的溶液中两者相互作用更强。圆二色谱(CD)实验结果也证实了这一结论。

基于壳聚糖膜固定双酶的胆碱传感器的研究

提出了一种基于壳聚糖膜固定辣根过氧化物酶-胆碱氧化酶的胆碱传感器的制备方法.该传感器以电聚合于玻碳电极的硫堇作为电子传递介体,在pH 6.8,外加电压-0.2 V(vs.SCE)条件下,其峰电流与浓度范围5.0×10-5～3.0×10-3 mol/L的胆碱呈良好的线性响应;检出限为1.0×10-5 mol/L.传感器有良好的选择性和稳定性,使用一月后,仍能保持其初始活性的80%.

多巴胺在硫堇衍生化自组装膜修饰金电极上的伏安行为及其安培测定

研究了多巴胺（ＤＡ）在硫堇衍生化自组装膜修饰金电极（Ｔｈ－ＳＡＭ／ＡＵｕ）上的电化学行为。ＤＡ在该修饰电极上的△Ｅｐ～７０ ｍＶ，循环伏安峰形对称，氧还峰电流之比接近 １，为准可逆反应。研究了温度、ｐＨ对ＤＡ氧化还原的影响，并求得了其热力学参数。在选定的条件下，峰电流与ＤＡ的浓度在１．０ × １０－６～１．０×１０－３ｍｏｌ／Ｌ的范围内呈线性关系，相关系数为０．９９２３，可用于ＤＡ的灵敏测定。