化学发光单孵多层免疫技术检测粪样中轮状病毒

以酶联免疫吸附分析（ＥＬＩＳＡ）夹心测定粪样中轮状病毒（ＲＶ）实验为模型，将传统又孵式免疫操作变成单孵式，即在包被ＲＶ抗体Ａｂ的微孔中同时加入含ＲＶ的粪样上清液和根过氧化物酶（ＨＲＰ）标记抗ＲＶ抗原共同孵育，其结果在载体表面形成多层酶免疫复合物，以ＨＲＰ催化鲁米诺－对碘苯酚－过氧化氢化学体系作为最终信号检测系统，从而建立起化学发光单孵多层免疫技术（ＣＬ－ＳＩＭＩＴ）。其灵敏度是ＥＬＩＳＡ的１６倍，     

Thermostability of landscape phage probes

Immunoassays have traditionally relied on antibodies as diagnostic probes. Their use outside of a laboratory, however, may be problematic because antibodies are often unstable in severe environmental conditions. Environmental monitoring requires thermostable probes, such as landscape phage, that carry thousands of foreign peptides on their surfaces, are superior to antibodies, and can operate in non-controlled conditions. While parent wild-type phage are known to be extremely stable in various media at high temperatures, no work has been done to demonstrate the stability of landscape phage probes. We examined the thermostability of a landscape phage probe and a monoclonal antibody specific for -galactosidase in parallel in an enzyme-linked immunosorbent assay (ELISA) format. They were both stable for greater than six months at room temperature, but at higher temperatures the antibody degraded more rapidly than the phage probe. Phage retained detectable binding ability for more than six weeks at 63 °C, and three days at 76 °C. The activation energy of phage degradation was determined to be 1.34×10⁵ J/mol. These results confirm that phage probes are highly thermostable and can function even after exposure to high temperatures during shipping, storage and operation.     

Synthesis of calix[4]arene library substituted with peptides at the upper rim

A fluorescence-labeled calix[4]arene library substituted with peptides at the upper rim was synthesized. Screening of the library for binding a dye-labeled oligopeptide indicated that some peptidocalix[4]arenes selectively bind the oligopeptide. The chemosensitivity of the library members for a target peptide was also investigated.     

Two Novel Antifungal Saponins from Tibetan Herbal Medicine Clematis tangutica

Antifungal assay-guided isolation of the ethanol extract of the aerial parts of Clematis tangutica yielded two novel triterpene saponins. Their structures were determined to be 3-O-α-L-arabinopyranosyl hederagenin 28-O-α-L-rhamnopyranosyl ester (1) and 3-O-β-D-glucopyranosyl-(1→4)-α-L-arabinopyranosyl hederagenin 28-O-α-L-rhamnopyranosyl ester (2) on the basis of spectral data and chemical reactions.     

Bioanalytical methods applied to endocrine disrupting polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans. A review

The usual methods for determining polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF) and polychlorinated biphenyls (PCB) are generally expensive and time consuming. This fact has favored the development of faster and cheaper techniques, based on immunoassays and bioassays. This paper reviews these bioanalytical methods and their analytical importance at the present moment.     

酶联免疫吸附法直接测定血清雌二醇

本合成了３种不同载体蛋白的雌二醇抗原，研究了载体蛋白免疫原性对雌二醇抗体产生的影响。应用酶联免疫吸附分析法测定了血清中雌二醇，浓度范围为５－１６０ｎｇ／ｍｌ（１．８×１０＾－＾８－５．９×１０＾－＾７ｍｏｌ／Ｌ）．ＲＳＤ％小于１０．％，检测限为１．９７ｎｇ／ｍｌ，相当于９８．５ｐｇ／孔（按空白平均值的二倍标准偏差计算）。另外，本还建立了一种用考马斯亮蓝Ｇ－２５０测定半抗原与蛋白结合比的方法，提     

Determining PPARγ-ligand binding affinity using fluorescent assay with cis-parinaric acid as a probe

Upon the study of small-molecules binding to proteins, the traditional methods for calculating dissociation constants (Kd and Ki) have shortcomings in dealing with the single binding site models. In this paper, two equations have been derived to solve this problem. These two equations are independent of the total concentration or initial degree of saturation of receptor and the activity of the competitive molecule. Through nonlinear fitting against these two equations, Kd value of a probe can be obtained by binding assay, and Ki value of a ligand can be obtained by competitive assay. Moreover, only the total concentrations of receptor([R]t), ligand([L]t) and probe([P]t) are required for the data fitting. In this work, Ki values of some typical ligands of PPARγ were successfully determined by use of our equations, among which the Ki value of PPARγ-LY171883 was reported for the first time.     

In vitro and in silico study of Aloe vera leaf extract against human breast cancer

Abstract

Aloe vera leaf contains some bioactive compounds that have a strong binding affinity toward estrogen receptor as compared to standard drug tamoxifen. In this study, we have found that the IC₅₀ of Aloe vera leaf extract against breast cancer cell line (MCF-7) is 23?µg/mL which is much lower than the IC₅₀ (332?µg/mL) of Aloe vera leaf extract against non-cancerous cell line (NIH-3T3). We have also calculated the total concentration of phenolic acid (385.662?µg/mL), flavonoids (160.402?µg/mL) and alkaloids (276.754?µg/mL) in Aloe vera leaf extract. The free radical scavenging activity of Aloe vera leaf extract is 67% to 89% (at 50 to 300?µg/ml). Our virtual molecular docking study suggests that bioactive compounds like Aloe-emodin (?8.8?Kcal/mol), 7-hydroxy-2,5 dimethylchromone (?7.5?Kcal/mol), Beta-sitosterol (?7.3?Kcal/mol) etc. have a greater binding affinity toward estrogen alpha receptor as compared to standard drug Tamoxifen (?6.4?Kcal/mol).

     

镍（Ⅱ）—p—MPAQ络合物极谱吸附波研究

5-[(对-甲基苯基)偶氮]-8-氨基喹啉(p-MPAQ)的合成及其在光度和荧光分析中的应用已有报道,但对其电化学性质未作研究,本文研究了p-MPAQ的极谱行为,在pH6.8的醋酸铵缓冲溶液中,p-MPAQ在-0.55 V呈现一示波极谱波(P_1),当有Ni~(2+)存在时,在-0.93V处出现一新峰(P_2),加0.0011％Triton X-100后,P_2波高明显增加实验证实该波为络合物     

Detection of single nucleotide polymorphisms using electrospray ionization mass spectrometry: validation of a one-well assay and quantitative pooling studies

Single nucleotide polymorphisms (SNPs) are currently being mapped and databased at a remarkable pace, providing a viable means for understanding disease susceptibility, differential drug response and human evolution. Consequently, there is an increasing demand for SNP genotyping technologies that are simple, rapid, cost effective and readily amenable to automation for high-throughput analyses. In this study, we improved the Survivor Assay, a SNP detection method based on electrospray ionization mass spectrometry (ESI-MS), with several developments. One improvement is the development of a one-well assay, requiring no off-line purification of the polymerase chain reaction product, achieved by simple addition of reagent solution into a single well. Another is the on-line separation of magnesium and dideoxynucleotides using an in-house made monolithic metal chelating column, eliminating any off-line sample preparation prior to mass spectrometric analysis. Here the Survivor Assay is extended from a proof-of-principle concept to a validated method by genotyping six SNPs from five different regions of human genomic DNA in 55 individual samples with 100% accuracy. This improved Survivor Assay eliminates the tedious and time-consuming steps of sample preparation, minimizes sample handing and offers a high-throughput analysis of SNPs by ESI-MS. The current combined preparation and analysis time is 2 min per sample. The simplicity of this method has potential for full automation and parallel chromatography and, thus, reduced analysis time. In addition, we have adapted the Survivor Assay for quantitative SNP analysis in pooled DNA samples. The capabilities and sensitivity of this approach were evaluated. We demonstrate that an allele occurring at a frequency of 2% can consistently be quantitated.