烷基酚与DNA相互作用的荧光光谱法研究

用荧光光谱法研究了环境激素辛基酚(OP)、壬基酚(NP)与小牛胸腺DNA(ctDNA)的相互作用.实验发现,随着ctDNA的加入,辛基酚、壬基酚的荧光光谱产生了有规律地猝灭,且最大发射峰红移.其中荧光猝灭是由于形成了烷基酚-DNA加合物而引起的静态猝灭.辛基酚、壬基酚与ctDNA均以插嵌模式相互作用,其结合常数分别为5.1×105 L·mol-1 和1.4×106 L·mol-1 ,结合位点分别为1.31和1.45.热力学参数确定了辛基酚及壬基酚与ctDNA的作用力类型主要是疏水作用力.     

三聚氰胺与鯡鱼精DNA相互作用研究

采用UV、荧光光谱、电化学和粘度法等方法研究了三聚氰胺(MM)与鲱鱼精DNA的作用机制, 并采用凝胶电泳考察了MM对pBR322质粒DNA迁移作用的影响. 当pH为7.0时, 动力学参数的计算结果表明: 加入DNA前后MM电荷转移系数α分别为0.27和0.26, 速率常数k_s分别为5.58 s^-1和5.65 s^－1; 热力学研究表明MM与DNA的结合常数K约为10⁵ mol^－1•L, MM与DNA可能是以沟槽式相结合.     

药物与DNA的相互作用研究——Ⅰ.小檗碱作为DNA的发光开关及pH的影响

用荧光光谱法研究了小檗碱与DNA的键合作用。发现小檗碱插入到DNA双螺旋中使小檗碱较弱的荧光带(λ_em=520 nm)的荧光强度显著提高。在pH=3.00附近，小檗碱-DNA体系的荧光增强到原来发射强度的69倍(I/I₀)。在pH=3.00和pH=7.20时，测得小檗碱与DNA的本征键合常数分别为3.00×10⁵和2.04×10⁵，二者的键合比分别为每分子小檗碱11.05和4.78个碱基对。     

农药异丙威与小牛胸腺DNA的作用研究

在生理酸度条件下,采用紫外光谱和荧光光谱法研究异丙威与小牛胸腺DNA的作用表明:DNA对异丙威的荧光有明显的猝灭作用,属于静态猝灭方式;K4[Fe(CN)6]猝灭试验发现DNA对异丙威有明显的保护作用,离子强度的改变对异丙威和异丙威-DNA体系的荧光均无明显影响;异丙威的加入使DNA的熔点升高,并且异丙威能够竞争置换EB与DNA的结合位点。上述实验也表明,异丙威以嵌插方式作用于DNA的结合位点,有可能通过形成DNA加合物的形式造成DNA损伤,从而最终导致基因突变。     

2-氯代苯甲醛丙氨酸席夫碱类抗癌药物对DNA作用的谱学研究

合成了2-氯代苯甲醛丙氨酸钾席夫碱(C₁₀H₉CINO₂K·H₂O，简写为2-CAK)及其Cu(Ⅱ)、Zn(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ)金属配合物［Cu(2-CA)₂］(C₂₀H₁₈Cl₂N₂O₄Cu·2H₂O)、［Zn(2-CA)₂］(C相似文献   

葛根素与DNA相互作用的光谱法研究

以中性红为光谱探针,采用荧光光谱和紫外-可见光谱法研究了葛根素与DNA的相互作用,考察了离子强度和I-离子浓度对葛根素与DNA作用的影响。结果表明,在生理条件下(pH 7.4),葛根素通过沟槽结合方式与DNA发生作用,DNA对葛根素荧光猝灭属于静态猝灭,测得其结合常数为4.81×104L/mol。     

免疫毛细管电泳-激光诱导荧光分析DNA加合物的方法学研究

DNA加合物是一类重要的生物标志物,可应用于人体致癌物暴露监测、癌症风险评价和人群易感性研究。DNA加合物作为生物标志物的应用需要安全、灵敏、快速的先进分析技术。我们利用免疫毛细管电泳-激光诱导荧光分析,发展了高灵敏的DNA加合物分析方法和技术。本文主要介绍了相关的仪器研制及方法学研究。方法学研究涉及DNA加合物荧光探针的合成和表征、抗体与DNA加合物的相互作用及其结合计量学、抗原-抗体复合物的稳定化和DNA驱动电泳聚焦技术。     

DNA加合物检测

DNA加合物是一类极其重要的、具有多种标志作用的生物标志物,可应用于环境致癌物的暴露监测、基因毒性测定、个体敏感性和环境致癌物与基因的相互作用研究、癌症风险评价、环境致癌因素筛查以及癌症预防研究等.可靠、灵敏、准确的分析检测技术是DNA加合物作为生物标志物得到广泛应用的关键.当前DNA加合物分析、检测的方法主要包括:32P后标记法、免疫分析法、免疫毛细管电泳激光诱导荧光法、液相色谱串联质谱法、微分离.质谱联用法等.本文对这些分析技术和方法及其在DNA加合物检测方面的应用做一简要综述.     

三聚氰胺-Cu~(2+)-ANS三元络合物荧光光谱法检测超痕量三聚氰胺

利用荧光光谱法研究了三聚氰胺(MEL)和Cu2+与8-苯胺-1-萘磺酸(ANS)的相互作用.研究表明,MEL和Cu2+均对ANS有荧光猝灭作用,且猝灭机理均为静态猝灭.计算了表观结合常数和结合位点数.Cu2+的引入使得MEL猝灭ANS荧光的效果急剧增强,体系的相对荧光峰强与MEL浓度(1×10-10～1×10-5 mol/L)的对数值呈良好的线性关系,三聚氰胺的检出限为3.8×10-11 mol/L.紫外、荧光、三维荧光光谱的结果表明,MEL及Cu2+对ANS的荧光猝灭为协同作用,三者形成了三元络合物.本研究建立了荧光光谱检测超痕量三聚氰胺的新方法,为奶粉、乳制品中三聚氰胺的检测提供了新思路.     

光谱法研究盐酸小檗碱与DNA的相互作用

采用荧光和紫外(UV)光谱等手段,研究了中药有效成分小檗碱(Ber)与脱氧核糖核酸(DNA)的键合作用。结果发现,小檗碱能插入到DNA双螺旋碱基对之间的空腔中,使小檗碱在eλm=530 nm处较弱的荧光强度显著提高;酸度显著影响其相互之间的作用;随着DNA浓度的增大,Ber的荧光强度增大,显示了很好的光敏性能。偏振、荧光猝灭实验等也进一步表明:Ber与DNA的作用方式主要是嵌插结合;离子强度的大小会影响Ber与DNA之间的作用。在pH=3.0适宜酸度条件下,建立了以Ber为探针定量测定DNA的分析方法。方法线性范围为0~5.2×10-5mol/L,精密度(RSD)为2.7%(n=7),检出限为1.43×10-7mol/L。     

用荧光关联谱单分子检测系统研究DNA分子

生命科学的发展对分析检测技术的灵敏度要求越来越高,人们希望在单分子水平上了解物质之间的相互作用以及生命的过程.     

胶体金免疫层析法快速检测三聚氰胺

采用戊二醛法制备三聚氰胺-BSA偶联抗原,胶体金标记三聚氰胺单克隆抗体,建立了检测三聚氰胺的胶体金免疫层析试验。结果显示,该试验具有良好的敏感性,胶体金免疫层析试验对鲜奶、奶粉和饲料样品中三聚氰胺的最低检测量分别为1.0、2.0和2.5μg/g,该法适合现场快速检测三聚氰胺。     

Selective melamine detection in multiple sample matrices with a portable Raman instrument using surface enhanced Raman spectroscopy-active gold nanoparticles

Melamine adulteration of food and pharmaceutical products is a major concern and there is a growing need to protect the public from exposure to contaminated or adulterated products. One approach to reduce this threat is to develop a portable method for on-site rapid testing. We describe a universal and selective method for the detection of melamine in a variety of solid matrices at the 100–200 μg L⁻¹ level by surface enhanced Raman spectroscopy (SERS) with gold nanoparticles. With minimal sample preparation and the use of a portable Raman spectrometer, this work will lead to field-based screening for melamine adulteration. Citrate coated gold nanoparticles (Au NPs) were investigated for both colorimetric and Raman-based responses. Several non-hazardous solvents were evaluated in order to develop a melamine extraction procedure safe for field applications. Au NP agglomerates formed by the addition of isopropanol (IPA) prior to sample introduction enhanced the Raman signal for melamine and eliminated matrix interference for substrate formation. The melamine Raman signal resulted in a 10⁵ enhancement through the use of Au NP agglomerates. To our knowledge, we have developed the first portable SERS method using Au NPs to selectively screen for the presence of melamine adulteration in a variety of food and pharmaceutical matrices, including milk powder, infant formula, lactose, povidone, whey protein, wheat bran and wheat gluten.     

荧光猝灭法研究氟比洛芬与DNA相互作用

采用荧光光谱法和紫外光谱法, 在生理条件下(pH=7.40)对氟比洛芬(FP)与脱氧核糖核酸(DNA)的作用方式进行了研究.证实了氟比洛芬通过沟槽结合方式与DNA发生相互作用.实验表明, DNA与氟比洛芬的相互作用为静态猝灭过程,测得结合常数为5.53×10~5 L·mol~(-1),结合位点数为1.12.     

An ultrasensitive method for the determination of melamine using cadmium telluride quantum dots as fluorescence probes

An ultrasensitive and simple method for the determination of melamine was developed based on the fluorescence quenching of thioglycolic acid (TGA) capped CdTe quantum dots (QDs) at pH 11.0. In strong alkaline aqueous solution, the selectivity of the method has been greatly improved due to most heavy metal ions show no interference as they are in the precipitation form or in their anion form. Furthermore, CdTe quantum dots have higher quantum yields at higher pH. The method has a wider concentration range and lower detection limit. The influence factors on the determination of melamine were investigated and the optimum conditions were determined. Under optimum conditions, the fluorescence intensity change of TGA coated CdTe quantum dots was linearly proportional to melamine over a concentration range from 1.0 × 10⁻¹¹ to 1.0 × 10⁻⁵ mol L⁻¹ with a correlation coefficient of 0.9943 and a detection limit of 5 × 10⁻¹² mol L⁻¹. The mechanism of fluorescence quenching of the QDs has been proposed based on the infrared spectroscopy information and electrophoresis experiments in presence of melamine under alkaline condition. The proposed method was employed to detect trace melamine in milk powder and pet feeds with satisfactory results.     

Binding of hairpin polyamides to DNA studied by fluorescence correlation spectroscopy for DNA nanoarchitectures

We have recently constructed a “DNA strut” consisting of two DNA-binding hairpin polyamides of Dervan-type connected via a long flexible linker and were able to show that this strut can be used to sequence-selectively connect DNA helices. This approach provides a second structural element (besides the Watson–Crick base pairing) for the assembly of higher-order DNA nanoarchitectures from smaller DNA building blocks. Since none of the existing analytical techniques for studying this kind of system were found suitable for detection and quantification of the formation of the resulting complexes, we chose fluorescence correlation spectroscopy (FCS). In the present study we show that FCS allowed us in a versatile and fast way to investigate the binding of Dervan polyamides to DNA. In particular it also shows its power in the quantitative detection of the formation of multimeric complexes and the in investigation of binding under nonphysiological conditions. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

羟基系列卟啉对三聚氰胺的检测研究

研究了四苯基卟啉(TPP)及5种羟基系列卟啉对三聚氰胺的检测,结果表明,TPP及羟基系列卟啉可以用来检测三聚氰胺,三聚氰胺与卟啉发生作用,导致其soret带特征峰强度的变化,其中邻二羟基卟啉对三聚氰胺的检测效果最好,检测限为0.2μg/L,摩尔吸光系数ε为0.6×106L·mol-1.cm-1。并对其作用机理进行了简要分析。     

UPLC-MRM法测定饲料中的三聚氰胺

提出了一种UPLC-MRM测定饲料中微量三聚氰胺的分析方法. 饲料经10 g/L三氯乙酸溶液提取和22 g/L乙酸铅溶液沉淀蛋白质, 过混合型阳离子交换柱(MCX)纯化, 离心后用0.45 μm滤膜过滤, 用超高效液相色谱-质谱-质谱联用仪(UPLC-MS-MS)分析测定, 以三聚氰胺母离子126.9 (m/z)和子离子67.5与84.6 (m/z)定性、定量目标物. 饲料样品加标回收率(n=6)为84.5%, 检测限0.01 μg/L, 相对偏差(RSD) 6.5%.     

Electron Tunneling in DNA

The reorganization energy that accompanies interfacial or through-strand electron tunneling in DNA is remarkably similar to that of a protein, and the attenuation factor for electron transfer between intercalated reagents also remains protein-like. These factors ensure rapid, but short-range electron tunneling through the duplex (shown schematically).