氧化石墨烯对DNA荧光分子探针FRET效应的研究

研究了氧化石墨烯的浓度、氧化石墨烯与DNA分子荧光探针的反应温度、DNA链长度对FRET效应的影响.研究表明,氧化石墨烯的浓度、氧化石墨烯与DNA分子荧光探针的反应温度、DNA链长度对FRET效应都有着重要的影响.氧化石墨烯浓度越大,其对DNA分子探针的荧光猝灭效率越高;氧化石墨烯与DNA分子荧光探针的反应温度越高,淬灭效率越高;DNA链越长,氧化石墨烯淬灭的效率越低.因此,氧化石墨烯的浓度、氧化石墨烯与DNA分子荧光探针的反应温度、DNA链长度对FRET效应都应该是设计生物传感器时考虑的因素.     

基于稀土复合纳米粒子的新型荧光共振能量移体系的建立及研究

采用简便的超声合成方法,成功的制备了稀土复合纳米粒子Tb/acety acetone(acac)/Polyacrylamide(PAM).该复合纳米粒子具有较高的稳定性,良好的分散性.基于该稀土复合纳米粒子为供体,罗丹明B为受体,建立了一种新型高效的荧光共振能量转移(FRET)体系.实验结果表明该供体-受体对之间具有较高的能量转移效率.     

Functionally independent subunits in the oligomeric structure of the GABA cotransporter rGAT1

We have combined structural and functional approaches to investigate the role of oligomerization in the operation of the GABA transporter rGAT1. Xenopus laevis oocytes were induced to express, either separately or simultaneously, the wild-type form of rGAT1 and a mutated (Y140W) form, unable to translocate GABA and to generate transport currents, although its intramembrane charge movement properties are only slightly affected. These characteristics, together with the insensitivity of Y140W to the blocking action of SKF89976A, were used to study the possible functional interaction of the two forms in an heteromeric structure. The electrophysiological data from oocytes coexpressing wild-type and Y140W rGAT1 were consistent with a completely independent activity of the two forms. Oligomerization was also studied by fluorescence resonance energy transfer (FRET) in tsA201 cells expressing the transporters fused with cyan and yellow fluorescent proteins (ECFP and EYFP). All combinations tested (WT-ECFP/WTEYFP, Y140W-ECFP/Y140W-EYFP and WT-ECFP/ Y140W-EYFP) were able to give rise to FRET, confirming the formation of homo- as well as heterooligomers. We conclude that, although rGAT1 undergoes structural oligomerization, each monomer operates independently. Received 18 July 2005; received after revision 21 September 2005; accepted 6 October 2005     

可单波长激发的荧光纳米粒子的合成与表征

根据荧光共振能量转移(FRET)原理,先选定了能级匹配的给体(4-乙氧基-9-(2-羟乙基)-1,8-萘二甲酰亚胺(EHNI))和受体(硝基苯并二恶唑基染料(NBD)),采用一步细乳液聚合方法将这2种生色团引入单个的聚合物纳米粒子.制得的荧光纳米粒子兼有EHNI和NBD 2种染料的光谱特性,证明了2种生色团已经结合进入纳米粒子中.并且通过改变这2种染料的掺杂比例,在单一波长激发下,通过发生荧光共振能量转移,聚合物纳米粒子表现出多色,及可调控、可区分的荧光发射信号.     

基于香豆素与CdTe量子点间的荧光共振能量转移检测超痕量Hg~(2+)的研究

分别合成了3-巯基丙酸稳定的CdTe@SiO2量子点和双臂香豆素金属离子荧光探针前体(BCP),并将BCP固定于CdTe@SiO2表面上形成Hg2+探针-CdTe@SiO2@BCP,建立了基于Hg2+对CdTe@SiO2@BCP量子点的荧光猝灭定量检测Hg2+的新方法。考察了pH值等因素的影响。在最佳实验条件下,可测定5.0×10-8~1.0×10-4mol·L-1的Hg2+,检出限为6.7×10-9mol·L-1,可应用于实际样品中超痕量Hg2+的测定。     

嗜热菌铁硫簇合成途径中SufB、SufC和SufD蛋白的表达、纯化及其功能初步研究

铁硫簇广泛存在于各种生物中,参与电子传递、底物结合和激活、基因表达和调控等重要功能.本文利用嗜热菌Thermus thermophilus HB8研究铁硫簇合成SUF系统中的三个关键蛋白SufB、SufC、SufD.以HB8的基因组为模板,通过PCR技术获得其sufB、sufC、sufD三个基因,随后构建了蛋白表达载体sufB-pET28a（＋）、sufC-pET28a（＋）、sufD-pGEX-6P-1,将其转入大肠杆菌Rosetta（DE3）进行蛋白表达,再利用亲和层析与凝胶过滤层析进行蛋白纯化.随后对SufB、SufC、SufD功能进行了初步研究,证明SufC对ATP具有亲和性,其亲和常数为15.2μmol/L;证明SufB与SufC在体外具有相互作用,并得到了复合体SufBC,为进一步探讨其作用机制奠定了基础.     

Fluorescent detection of singlet oxygen: Amplifying signal transduction and improving sensitivity based on intramolecular FRET of anthryl appended porphyrins

Two new anthryl-appended porphyrin dyads have been synthesized and used as highly selective and sensitive fluorescence probes for singlet oxygen ( 1O2 ). The design strategy for the probes is directed by the idea of intramolecular fluorescence resonance ener- gy transfer (FRET) interactions and carried out by incorporation of an electron-rich fluorophore (porphyrin) with a reactive anthracene for 1O2 . The molecular recognition is based on the specific interaction of 1O2 with the inner anthracene moiety, an...     

Preparation of multi-color quantum dots and its application to immunohistochemical analysis

Quantum dots （QDs） have the potential to be used in the multiplexed bioanalysis for their unique property： multi-color QDs can be excited at the same single wavelength light. In this work, high quantum yield multi-color core/shell QDs were prepared. After being water-solubilized by amphiphilic polymer based on self-assembling, the QDs would be labeled by two different IgGs and used in the multiplexed biodetection. Fluorescence resonance energy transfer （FRET） should be avoided in the multiplexed biodetection. In this work, spectral analysis showed that no FRET appeared in watersoluble QDs modified by amphiphilic polymer. The immunofluorescence in vitro indicated that the QDs- IgGs bioconjugates had excellent species-specific detection ability with nearly non-specific binding. The setting of this model will help to support the application of multi-color QDs in the multiplexed bioanalysis communities.