A high-throughput fluorescent polarization assay for nuclear receptor binding utilizing crude receptor extract.

A homogenous high-throughput assay has been developed to measure the binding between nuclear receptors and test compounds. This assay applies a fluorescence polarization (FP) detection method using human glucocorticoid receptor (GR) as a model system. Crude receptor extract, which requires no additional purification, is used in the assay. The binding conditions (i.e., DMSO tolerance, temperature, stability, and variability) have been investigated and validated. At the optimized conditions, a signal-to-background ratio of 2:1 and a Z'-factor of 0.7 was achieved in a 384-well format. Several known strong and weak GR ligands have been evaluated in this system. Possible interference of fluorescent compounds and methods to identify false positives are also discussed. This FP-based assay system can potentially be used for many soluble nuclear receptors in high-throughput binding assays.     

Potential chemical transformation of phosphinic acid derivatives and their applications in the synthesis of drugs

The chemical transformation of phosphinic acid is a well-considered mature area of research on account of the historical significant reactions such as Kabachnik–Fields, Mannich, Arbuzov, Michaelis–Becker, etc. Considerable advances have been made over last years especially in metal-catalyzed, free-radical processes and asymmetric synthesis using catalytic enantioselective. As a result, the aim of this synopsis is to make the reader familiar with advances in the approaches of phosphinic acids toward the synthesis of highly functionalized and valuable buildings blocks. Another purpose of this survey is to provide the current status of the applications of phosphinic acids in the synthesis of drugs.     

人源分泌型血管内皮细胞生长因子受体flt-1（Ⅰ～Ⅳ区）的基因克隆及其腺病毒载体的构建和表达

肿瘤的生长、转移与血管形成密切相关,利用基因治疗的方法将抗血管形成的因子导入体内是目前肿瘤生物治疗研究的重要策略.血管内皮细胞生长因子（VEGF）在血管生成中起重要作用,因此阻断VEGF与相应受体的结合成为抗血管形成的重要靶点.通过RT-PCR从人脐静脉内皮细胞克隆了VEGF受体Flt-1的信号肽及胞外Ⅰ～Ⅳ区cDNA,即可溶性sFlt-1的cDNA片段.利用Ad-Easy体系, 在细菌BJ5183中同源重组后,转染包装细胞293,成功包装出重组flt-1腺病毒,利用它可有效地感染低分化胃黏液腺癌细胞株MGC803.经RT-PCR,免疫沉淀及免疫印迹等不同方法检测表明,被感染细胞能表达并分泌Flt-1的胞外区蛋白,为后续进行抗肿瘤血管形成的基因治疗研究奠定了基础.     

Influence of cell equivalent spherical diameter on the growth rate and cell density of marine phytoplankton

The maximal growth rates (μ_max) of 8 species of marine phytoplankton were studied in detail. A Logistic growth model was used to describe the growth process of phytoplankton and the averaged plotting correlation coefficient was 1.00 ± 0.01 (mean ± standard deviation). The size distribution of phytoplankton could be well represented by single or combined Gaussian distribution functions. The size distribution of phytoplankton was investigated by daily analysis, and the variation of the median equivalent spherical diameter (MESD) was recorded. The size of algal cells varied throughout the process of population growth, and the size distribution characteristic of the two species of pyrrophytes investigated also changed during the growth process. The relation between maximum growth rate and MESD could be expressed by the equation μ_max = a * MESD^b (where μ_max is the maximum specific growth rate, MESD is the median equivalent spherical diameter, and a and b are constants equal to 2.10 × 10⁵ and − 1.15, respectively), estimated by nonlinear regression analysis with the allometric function. The dependence of maximum cell density on algal MESD was also investigated and the relationship B_f = 1.56 × 10⁷ MESD^− 1.20 was obtained (where B_f is the maximum cell density).     

鲜茶叶中表没食子儿茶素没食子酸酯的高效提取技术研究

采用鲜磨匀浆提取、负压空化混悬组合技术对新鲜老龄茶叶中的没食子酸酯(EGCG)进行了高效提取,并与干燥老龄茶叶的传统提取工艺进行了对比。结果表明：组合工艺的最佳提取条件为新鲜老龄茶叶高温杀青后,再经常温水匀浆萃取,固液比为1:10,匀浆萃取时间为1 min,滤渣再经负压空化混悬固液提取,固液比为1:10,空化时间为15 min,空化提取2次。新鲜老龄茶叶最佳组合工艺的EGCG提取量为502.85 mg,优于传统干燥老龄茶叶工艺。     

Orthotropic properties of cancellous bone modelled as parameterized cellular material

Analysis of stresses and strains in bone tissues and simulation of their adaptive remodelling require exhaustive information about distribution of constitutive properties of cancellous bone and their relationships to microstructural parameters. Homogenization of “equivalent” trabecular microstructures appears to be an advantageous tool for this task. In this study, parameterized orthotropic constitutive models of cancellous bone are derived from finite element analysis of repeatable microstructure cells. The models, based on a space-filling dodecahedron, are fully three-dimensional and are parameterized with four shape parameters. Variation of the parameters allows to imitate most of typical microstructure patterns observed in real bones, along with a variety of intermediate geometries. Finite element models of cells are generated by a special-purpose structured mesh generator for any arbitrary set of shape parameter values. Static numerical tests are performed for an exhaustive number of parameter value sets (microstructure instances). Coefficients of elastic orthotropic stiffness matrix are determined as tabularized functions of elastic constants versus the shape parameters. Additionally, they are correlated to apparent density and principal fabric tensor values. Comparison of the results with micro-FE data obtained for a large set of cancellous bone specimens proves a good agreement.     

Linking irradiance-induced changes in pit membrane ultrastructure with xylem vulnerability to cavitation

The effect of shading on xylem hydraulic traits and xylem anatomy was studied in hybrid poplar (Populus trichocarpa x deltoides, clone H11-11). Hydraulic measurements conducted on stem segments of 3-month-old saplings grown in shaded (SH) or control light (C) conditions indicated that shading resulted in more vulnerable and less efficient xylem. Air is thought to enter vessels through pores in inter-vessel pit membranes, thereby nucleating cavitation. Therefore, we tested if the ultrastructure and/or chemistry of pit membranes differed in SH and C plants. Transmission electron micrographs revealed that pit membranes were thinner in SH, which was paralleled by lower compound middle lamella thickness. Immunolabelling with JIM5 and JIM7 monoclonal antibodies surprisingly indicated that pectic homogalacturonans were not present in the mature pit membrane regardless of the light treatment. Porosity measurements conducted with scanning electron microscopy were significantly affected by the method used for sample dehydration. Drying through a gradual ethanol series seems to be a better alternative to drying directly from a hydrated state for pit membrane observations in poplar. Scanning electron microscopy based estimates of pit membrane porosity probably overestimated real porosity as suggested by the results from the 'rare pit' model.     

In situ surface electrochemical characterizations of Ti and Ti-6Al-4V alloy cultured with osteoblast-like cells

The biocompatibility of metal implants is related to their surface electrochemical characterizations. The in situ growing process of osteoblast-like U-2 OS cells on polished Ti and Ti-6Al-4V alloy during 72h incubation was monitored using the electrochemical impedance spectroscopy (EIS) measurement technique. The results showed that the presence of cells on metals led to an increase in the impedance and polarization resistance (R(p)) of metals. The impedance and R(p) increased as the cells grew (i.e., from adhesion, spreading to proliferation period). A trace amount of V element released from Ti-6Al-4V alloy led to a lower R(p) with respect to Ti metal during cell culture. In this study, a satisfactory equivalent circuit simulating the electrochemical characterizations of Ti and Ti-6Al-4V alloy cultured with cells was proposed. The EIS measurement technique was applied successfully to monitor the in situ growing process of U-2 OS cells on Ti and Ti-6Al-4V alloy.     

Analytical and numerical construction of equivalent cables

The mathematical complexity experienced when applying cable theory to arbitrarily branched dendrites has lead to the development of a simple representation of any branched dendrite called the equivalent cable. The equivalent cable is an unbranched model of a dendrite and a one-to-one mapping of potentials and currents on the branched model to those on the unbranched model, and vice versa. The piecewise uniform cable, with a symmetrised tri-diagonal system matrix, is shown to represent the canonical form for an equivalent cable. Through a novel application of the Laplace transform it is demonstrated that an arbitrary branched model of a dendrite can be transformed to the canonical form of an equivalent cable. The characteristic properties of the equivalent cable are extracted from the matrix for the transformed branched model. The one-to-one mapping follows automatically from the construction of the equivalent cable. The equivalent cable is used to provide a new procedure for characterising the location of synaptic contacts on spinal interneurons.