共振瑞利散射测试血清蛋白酸碱度影响的探讨

提出了一种基于共振瑞利散射（RRS）原理测量人体血清蛋白的新方法。在缓冲溶液的作用下,把配制好的人体血清蛋白稀释液按比例与四羧基酞菁锌混合,经过化学作用后在波长为400 nm左右蓝色波段强光照射下,散射出480 nm左右的共振瑞利散射光强信号。考察在不同pH对共振瑞利散射光强信号与混合物中的血清蛋白反应线性关系的影响。结果表明,pH在6.0～8.0范围内混合溶液共振瑞利散射光强信号与血清蛋白的线性关系良好。     

ctDNA与离子型表面活性剂相互作用的共振瑞利散射法研究

利用共振瑞利散射光谱(RRS)方法研究了ctDNA与离子型表面活性剂的相互作用.结果表明:阳离子表面活性剂通过静电、疏水等作用在ctDNA表面聚集,造成ctDNA的RRS大大增强;阴离子表面活性剂对吖啶橙(AO)与ctDNA的相互作用有协同作用,能使AO-ctDNA的RRS信号大大增强.     

改良钼锑抗比色法测定不同谷子材料组织磷含量

缺磷已成为目前制约作物产量提高的非生物胁迫之一,筛选作物耐低磷资源,进行作物耐低磷育种已成为作物科学当前研究的热点之一,因此植物体内磷含量的及时有效的监测也变得尤为重要。本文通过改良前后的钼锑抗比色法测定谷子新鲜幼嫩叶片和幼嫩根系的组织磷含量,发现改良后的钼锑抗比色法所测的磷含量在一定范围内有良好的线性关系,线性方程为y=1. 060 3x-0. 010 3,线性相关系数达0. 998 1。用该方法对谷子新鲜幼嫩叶片、幼嫩根系、成熟叶片、成熟根系、新鲜幼穗、成熟茎秆及液氮冷冻后的相应组织和谷子籽粒的磷含量以及不同磷浓度处理下(0. 005、0. 250 mmol/L)的谷子材料的磷含量进行测定,进一步证实了其具有良好的灵敏度和精密度。该方法所测得的标准偏差较小,在0～0. 015 8范围之内;相对标准偏差(RSD)的范围在0%～1. 81%;检出限的范围在0～0. 047 4μg/mL,重复性较好,利用该方法还可有效地筛选具有磷吸收效率差异的谷子品种。改良后的钼锑抗比色法测定结果线性良好,标准差低,精密度很理想,适合植物中低浓度磷的测定,可为不同谷子材料总磷测定提供依据和参考。     

表面等离子体共振技术在药物研究中的应用

表面等离子体共振(surface plasmon resonance,SPR)技术作为一种新型的免标记、实时在线研究生物分子间相互作用的高灵敏传感技术,已经在生命科学领域中得到了大量应用。该文简要介绍了SPR生物传感器的基本原理,重点评述了其在新药筛选和药物作用机制方面的研究进展,并对其前景进行了展望。     

用荧光共振能量转移研究synaptotagmin 胞质部分的寡聚化

目前人们公认synaptotagmin在神经递质释放过程中作为钙离子感受器而发挥作用。以前的研究发现,synaptotagmin存在两种形式的寡聚化,一种是通过跨膜区以及随后的中间链部分介导的寡聚化;另一种是通过胞质部分（C2AB）介导的寡聚化。对于后者有很多争议。在这篇文章中,作者用荧光共振能量转移的方法,在尽可能接近生理的条件下,证明了C2AB在有细胞膜和游离的钙离子的条件下能够寡聚化。而且,抽提细胞膜上的胆固醇或者封闭膜上的磷酸肌醇二磷酸能抑制C2AB在膜上的寡聚。     

单分子荧光共振能量转移技术在核糖体移位研究中的进展

核糖体是蛋白质的"合成工厂",也是临床上多种抗菌药物的作用靶点,因此,深入理解细菌核糖体的蛋白质翻译机制意义重大.蛋白质翻译是通过多步骤相互协调、多组分精细配合来实现高保真和精确调控.核糖体在mRNA上的移位作为翻译过程中最重要的事件之一,需要核糖体大规模的构象重排以及tRNA2-mRNA沿着核糖体的精确移动.在细菌中,移位是由延伸因子EF-G催化GTP水解来驱动的.近年来,单分子荧光共振能量技术(smFRET)的发展使得人们可以探究单个tRNA分子移位的动力学过程并实时观测核糖体的构象变化.本文首先介绍了smFRET技术的原理及特点,对其在核糖体结构动态及tRNA移位研究中的应用进行了较为系统的总结,并对其应用前景进行了展望.     

抗癌药物ADM与DNA相互作用的紫外共振拉曼光谱的研究

用紫外共振拉曼光谱研究了ＡＤＭ与小牛胸腺ＤＮＡ相互作用,分析表明：ＡＤＭ插入ＤＮＡ的ＧＣ－ＣＧ位置;ＡＤＭ与ＤＮＡ之间的主要相互作用是蒽环π电子与碱基Ｇ和Ｃ的π电子形成的π－π电子相互作用,并通过碱基Ｇ、Ｃ的ＮＨ＿２的氨的孤对Ｐ电子与ＡＤＭ的π电子形成的π－Ｐ电子相互作用以及ＡＤＭ和ＤＮＡ碱基Ｇ、Ｃ和ＰＯ＿２之间形成的氢键使相互作用加强;ＡＤＭ插入ＤＮＡ使其构象产生一定变化,但未破坏ＤＮＡ碱基对间的氢键。     

枯草菌HemAT蛋白质结合配基O2的构象变化——紫外共振拉曼光谱研究

枯草菌HemAT蛋白质是新近发现的一种基于血红素的趋氧性同型二聚体蛋白质。作者对此蛋白质进行了表达和提纯。用紫外共振拉曼光谱研究了全分子和传感域HemAT在与配基O2结合时的构象变化。发现O2配基与HemAT蛋白质的结合使传感域中Trp和Tyr的环境发生变化,而对连接域中Tyr的环境影响可忽略不计。信号发送域对O2配基引起的Trp和Tyr的环境变化不产生影响。O2配基与HemAT蛋白质的结合使得G-螺旋发生位移,传感域与信号发送域通过某种互感方式把O2结合信号从传感域传递到信号发送域。     

α-α交联的Fe-Co杂化血红蛋白的轴向键Fe-Nε共振拉曼谱研究

通过将HbA和变异HbC(Glu6→Lys)交联制得的各种Co取代的Fe-Co杂化血红蛋白进行血红蛋白氧合过程的模拟研究,用共振拉曼技术研究它们在载氧、去氧和一氧化碳配位(无IHP或有IHP)时的轴向共价键Fe-Nε(F8-His)伸缩振动证明,在血红蛋白配位过程中,第一个配体配位到β(Fe)亚基上所引起的构象变化比配位到α(Fe)亚基的大;因而,配位分子应首先结合在α(Fe)亚基上,血红蛋白四聚体配位过程T/R态构象根本转变发生在第二个配位之时或之前;而且,可能存在除T、R态外的其它构象状态。     

细胞色素C与细胞色素氧化酶之间相互作用的共振RAMAN光谱研究

分别于５１４．５ｎｍ及６０４ｕｍ波长激发下,对游离的细胞色素Ｃ,细胞色素氧化酶以及细胞色素Ｃ和细胞色素氧化酶的复合体的共振拉曼光谱进行了分析比较,在形成复合体时,双方蛋白的共振拉曼谱均有所变化,一个共同的特征性变化是Ａ２ｇｖ２２１１３０ｃｍ－１,ｖ２１１３１２ｃｍ－１,ｖ２０１４００ｃｍ－２,和ｖ１９１５８４ｃｍ－１强度都有增强,其中变化最明显的是Ａ２ｇｖ１９１５８４ｃｍ－１峰,在游离态中,Ｉ１５４０／ｉ１５８２＞１,在结合态中Ｉ１５５０／Ｉ１５８２＜１。     

金纳米探针瑞利共振散射法测定溶菌酶

利用共振散射技术研究了金纳米微粒与溶菌酶的相互作用.金纳米微粒可以通过静电引力及疏水作用与溶菌酶结合,使金纳米微粒粒径变大,从而导致纳米金瑞利共振散射光谱显著增强,并且在一定范围内光散射强度的增加量与溶菌酶浓度成正比.考查了作用时间、溶液酸度、共存离子及有机溶剂等条件的影响.将纳米金作为测定溶菌酶的探针,在最佳反应条件下,对溶菌酶的检出限为0.08 μg/mL.将此方法用于蛋清中溶菌酶的测定,检测结果与文献报道方法一致,结果令人满意.     

The Determination of Deoxyribonucleic Acids with Triadimenol Based on the Enhancement of Resonance Light Scattering

For the first time, triadimenol was used to determine nucleic acid (DNA) using the resonance light scattering (RLS) technique. The RLS of triadimenol was greatly enhanced by DNA in the range of pH 1.6 ～ 1.9. A resonance light‐scattering peak at 310nm was found, and the enhanced intensity of RLS at this wavelength was proportional to the concentration of DNA. The linear range of the calibration curve was 0 ～ 9 µg/ml with the detection limit of 24 ng ml^? 1. The mechanism studies of the system indicated that the enhanced RLS is due to the aggregation of triadimenol on DNA. The nucleic acids in synthetic samples and in rice seedling extraction were analyzed with satisfactory results. Compared with other methods, this method is convenient, rapid, inexpensive and simple.     

Resonance Rayleigh-scattering method for the determination of proteins with gold nanoparticle probe

Gold nanoparticles with a 12-nm diameter were used as probes for the determination of proteins by resonance Rayleigh-scattering techniques. In weak acidic solution, large amounts of citrate anions will self-assemble on the surface of positively charged gold nanoparticles to form supermolecular compounds with negative charges. Below the isoelectric point, proteins with positive charges such as human serum albumin (HSA), bovine serum albumin (BSA), and ovalbumin (Ova) can bind gold nanoparticles to form larger volume products (the diameter of the binding product of gold nanoparticles with HSA is 23 nm.) through electrostatic force, hydrogen bonds, and hydrophobic effects, which can result in a red shift of the maximum absorption wavelength, the remarkable enhancement of the resonance Rayleigh-scattering intensity (RRS), and the appearance of the RRS spectra. At the same time, the second-order-scattering (SOS) and frequency-doubling-scattering (FDS) intensities are also enhanced. The binding products of gold nanoparticles with different proteins have similar spectral characteristics and the maximum wavelengths are located near 303 nm for RRS, 540 nm for SOS, and 390 for FDS, respectively. The scattering enhancement (DeltaI) is directly proportional to the concentration of proteins. Among them, the RRS method has the highest sensitivity and the detection limits are 0.38 ng/ml for HSA, 0.45 ng/ml for BSA, and 0.56 ng/ml for Ova, separately. The methods have good selectivity. A new RRS method for the determination of trace proteins using a gold nanoparticle probe has been developed. Because gold nanoparticle probes do not need to be modified chemically in advance, the method is very simple and fast.     

Resonance Rayleigh scattering method for the determination of chitosan with some anionic surfactants

In weak acidic buffer medium, chitosan binding with an anionic surfactant, such as sodium dodecyl benzene sulphonate (SDBS), sodium lauryl sulphate (SLS) or sodium dodecyl sulphonate (SDS), can result in a significant enhancement of resonance Rayleigh scattering (RRS) intensity. The results showed that under optimum conditions the enhanced RRS intensity is proportional to the concentration of chitosan in the range 0.10–20.0 µg/mL for SDBS, 0.27–15.0 µg/mL for SLS and 0.20–15.0 µg/mL for SDS. Among these, the sensitivity of SDBS is the highest and its detection limit for chitosan is 29 ng/mL, while those of SLS and SDS are 83 and 61 ng/mL, respectively. The method has good selectivity and was applied to the determination of trace amounts of chitosan in practical samples with satisfactory results. Therefore, a simple and convenient method with high sensitivity and selectivity for the determination of chitosan was established. Copyright © 2008 John Wiley & Sons, Ltd.     

Non-identifiability of the Rayleigh damping material model in Magnetic Resonance Elastography

Magnetic Resonance Elastography (MRE) is an emerging imaging modality for quantifying soft tissue elasticity deduced from displacement measurements within the tissue obtained by phase sensitive Magnetic Resonance Imaging (MRI) techniques. MRE has potential to detect a range of pathologies, diseases and cancer formations, especially tumors. The mechanical model commonly used in MRE is linear viscoelasticity (VE). An alternative Rayleigh damping (RD) model for soft tissue attenuation is used with a subspace-based nonlinear inversion (SNLI) algorithm to reconstruct viscoelastic properties, energy attenuation mechanisms and concomitant damping behavior of the tissue-simulating phantoms. This research performs a thorough evaluation of the RD model in MRE focusing on unique identification of RD parameters, _μI${\mu }_I$ and _ρI${\rho }_I$.     

A simple and sensitive resonance Rayleigh scattering method for determination of As(III) using aptamer‐modified nanogold as a probe

A simple and selective aptamer (ssDNA)‐modified nanogold probe (AussDNA) was prepared for the determination of trace As(III) in HEPES buffer solution (pH 8.2) containing 0.05 mol/L NaCl. The method coupled the aptamer reaction of AussDNA–As(III) and the resonance Rayleigh scattering (RRS) of nanogold aggregations at 278 nm. When the As(III) concentration increased, the RRS intensity at 278 nm increased to form more nanogold aggregation and a stable As(III)–ssDNA complex. Under selected conditions, the increased RRS intensity (ΔI) was linear to the concentration of As(III) in the range 3.8–230.4 ng/mL, with a detection limit of 1.9 ng/mL. This RRS method was applied to detect As(III) in water samples, with simplicity, sensitivity and selectivity. Copyright © 2013 John Wiley & Sons, Ltd.     

Resonance Rayleigh scattering methods for the determination of chitosan with Congo red as probe

Two methods were presented for the sensitive and selective determination of chitosan (CTS) with Congo red (CR) as probe based on resonance Rayleigh scattering (RRS) intensities in health products. In weakly acidic buffer solution, the binding of CTS to CR, could result in the enhancement of the RRS intensities. Moreover, after adding OP emulsifier (octyl‐phenyl polyoxyethylene ether) to the system, the RRS intensities showed more significantly enhancement. The maximum RRS signals for the CTS–CR system and the CTS–CR–OP system were located at 380 nm and 376 nm, respectively. Under optimum experimental conditions, the increased RRS intensities (ΔI) of these two systems were linear to CTS concentration in the range of 0.40–8.00 μg/ml and 0.05–1.00 μg/ml. Their limits of detection (LOD) were 44.81 ng/ml and 6.99 ng/ml, which indicated that the latter system was more sensitive than the former. In this work, the optimum conditions and the effects of some foreign substances on the determination were studied. In addition, the effect of the molecular weight of CTS and the reasons for the enhancement of resonance light scattering were discussed. Finally, these two methods were applied to the determination of chitosan in health products with satisfactory results.     

Protein analysis with tetra-substituted sulfonated cobalt phthalocyanine by the technique of Rayleigh light scattering

This is the first report of cobalt-tetrasulfonatophthalocyanine (CoTSPc) as a probe of Rayleigh light scattering (RLS) to determine proteins at nanogram levels. A highly sensitive method has been developed for the determination of proteins by the light scattering technique on a common spectrofluorimeter, based on the fact that the weak RLS of CoTSPc can be greatly enhanced in the presence of proteins. Under optimum conditions, the linear ranges of the calibration curves were 0.10-34.3 microg x mL(-1) for both human serum albumin and bovine serum albumin, with detection limits of 15.5 and 13.9 ng x mL(-1), respectively. Moreover, there is almost no interference of any amino acids and metal ions. The method has been applied to the direct determination of total proteins in human serum samples, and the results were satisfactory with clinical data provided.     

Determination of doxepin hydrochloride in spiked human plasma and capsule after derivatization with eosin Y using resonance Rayleigh scattering,second-order scattering and frequency doubling scattering methods

Doxepin hydrochloride (DOX) is a tricyclic antidepressant drug. Three sensitive spectrofluorimetric methods, namely resonance Rayleigh scattering (RRS), frequency doubling scattering (FDS) and second-order scattering (SOS), were developed and validated for their estimation of doxepin in spiked human plasma and formulation using liquid–liquid extraction method through the formation of an ion pair complex with eosin Y at a pH of 4.5. Various factors affecting fluorescence intensity were optimized, and the reaction kinetics was determined using the Arrhenius equation method. Different scattering methods such as RRS, FDS and SOS were developed at maximum scattering wavelengths λ_ex/λ_em = 567/567 nm for RRS, 720/360 nm for SOS and 260/520 nm for FDS, respectively. The methods exhibited high sensitivities, and the detection limits for DOX were found to be 0.82, 1.20 and 1.03 ng/ml for RRS, FDS and SOS methods, respectively. The FDS method exhibited the highest sensitivity. The methods were validated using the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines and applied to determine DOX in capsule and spiked human plasma samples.     

Chiral Recognition of Tyrosine Enantiomers Based on Decreased Resonance Scattering Signals With Silver Nanoparticles as Optical Sensor

A novel chiral sensing platform, employing silver nanoparticles capped with N‐acetyl‐L‐cysteine (NALC‐Ag NPs), was utilized for the discrimination of L‐tyrosine and D‐tyrosine. This nanosensor, which could be used as an optical sensing unit and chiral probe, was characterized by transmission electron microscopy (TEM) and resonance Rayleigh scattering (RRS) spectroscopy. After the proposed sensing platform interacted with L‐tyrosine and D‐tyrosine, a decreased resonance scattering signal was only obtained from L‐tyrosine. This phenomenon offered a useful assay for the selectivity and determination of L‐tyrosine with the RRS method. The linear range and detection limit of L‐tyrosine were 0.2838–20.0 µg⋅mL^‐1 and 0.0860 µg⋅mL^‐1, respectively. In addition, experimental factors such as acidity, interaction time, and the concentration of enantiomers were investigated with regard to the effect on enantioselective interaction. Chirality 27:194–198, 2015. © 2014 Wiley Periodicals, Inc.