A Commercial Nonbinding Surface Effectively Reduces Fibrinogen Adsorption but Does Not Prevent Platelet Adhesion to Fibrinogen

A commercial nonbinding surface effectively prevents protein adsorption; however, the platelet phenotype on this surface has yet to be defined. This study evaluates platelet adhesion and adsorption of several plasma/extracellular matrix (ECM) proteins to the nonbinding surface compared to other commonly used nontreated and high-binding surfaces. Platelet adhesion to uncoated microplates and those coated with fibrinogen or collagen is quantified by colorimetric assay. The binding capacity of the examined surfaces for plasma/ECM proteins is evaluated by measuring the relative and absolute protein adsorption. Compared to other surfaces, the nonbinding surface effectively prevents platelet adsorption, i.e. by 61-93% (Enzyme-Linked Immunosorbent Assay, ELISA), and reduces platelet adhesion, i.e. by 92%, when not coated with any protein. The nonbinding surface also decreases platelet deposition on collagen (up to 31%), but not fibrinogen. The nonbinding surface seems to be more of a low-fouling than nonfouling material, as it is able to reduce fibrinogen adsorption but not prevent platelet adhesion to fibrinogen. This feature should be considered when using the nonbinding surface for in vitro platelet testing.     

Anti-allergic activity of 3, 5, 6, 7, 8, 3′, 4′-heptamethoxyflavone extracted from Citri Reticulatae Pericarpium

The inhibitory activity of 3, 5, 6, 7, 8, 3′, 4′-heptamethoxyflavone extracted from Citri Reticulatae Pericarpium on RBL-2H3 cells degranulation was done by two different methods. At low concentration, the values of inhibition obtained by modified method were much larger than that of the classical method. Spectroscopic measurements and molecular docking calculation were applied to study the mechanism. It was induced by interaction between flavonoid and immunoglobulin E. Compared with the interaction between antibody and receptor, the force was weak, the inhibitory effect on β-hexosaminidase release was strong, with some structural changes to the antibody.     

Subsynaptic Distribution,Lipid Raft Targeting and G Protein-Dependent Signalling of the Type 1 Cannabinoid Receptor in Synaptosomes from the Mouse Hippocampus and Frontal Cortex

Numerous studies have investigated the roles of the type 1 cannabinoid receptor (CB1) in glutamatergic and GABAergic neurons. Here, we used the cell-type-specific CB1 rescue model in mice to gain insight into the organizational principles of plasma membrane targeting and Gαi/o protein signalling of the CB1 receptor at excitatory and inhibitory terminals of the frontal cortex and hippocampus. By applying biochemical fractionation techniques and Western blot analyses to synaptosomal membranes, we explored the subsynaptic distribution (pre-, post-, and extra-synaptic) and CB1 receptor compartmentalization into lipid and non-lipid raft plasma membrane microdomains and the signalling properties. These data infer that the plasma membrane partitioning of the CB1 receptor and its functional coupling to Gαi/o proteins are not biased towards the cell type of CB1 receptor rescue. The extent of the canonical Gαi/o protein-dependent CB1 receptor signalling correlated with the abundance of CB1 receptor in the respective cell type (glutamatergic versus GABAergic neurons) both in frontal cortical and hippocampal synaptosomes. In summary, our results provide an updated view of the functional coupling of the CB1 receptor to Gαi/o proteins at excitatory and inhibitory terminals and substantiate the utility of the CB1 rescue model in studying endocannabinoid physiology at the subcellular level.     

毒素DON单链抗体的同源建模及与DON结合的分子模拟研究

通过同源模建及分子力学构建并优化了呕吐毒素DON单链抗体的三维结构, 结合Procheck和verify_3D方法评估得到合理的抗体模型. 利用分子对接方法研究了单链抗体与其抗原DON的识别及相互作用. 结果表明, 毒素结合到抗体轻链上, 通过轻重链的交界区残基与重链结合, 与残基Pro107之间存在氢键作用. 采用分子动力学模拟和MM/GBSA方法计算了毒素DON与抗体之间的结合自由能, 计算结果与实验值相吻合, 体系疏水相互作用是维持复合物稳定结构的主要驱动力. 动力学模拟氢键分析和能量分解结果共同表明, 残基Pro107参与稳定氢键的形成并贡献很强的范德华作用, 是毒素结合抗体最关键的残基. 本研究为该毒素抗体的结构设计提供了重要的线索和理论依据, 对毒素类分子新型抗体的研究和开发具有理论指导价值.     

荧光各向异性法快速测定荧光标记物对蛋白质的标记比

免疫荧光技术是免疫学检测的重要手段之一,该技术在病原微生物的早期诊断、自身免疫研究、抗原或抗体的免疫组化定位等方面都得到了广泛应用^[1].荧光色素对抗体(或抗原)标记比的测定是免疫荧光技术的重要部分.     

具有cGPX活力的含硒抗体酶的酶学及动力学性质研究

通过单克隆抗体制备技术得到三株特异结合半抗原4(GSH-S-DNP二苄酯)的单克隆抗体HB4,HB5和HB7.抗体经两步化学诱变得到具有细胞谷胱甘肽过氧化物酶(cGPX)活性的含硒抗体酶mHB4,mHB5和mHB7,活力分别为170,1867,32U/μmol.其中mHB5的活力是天然兔肝cGPX的0.32倍,m4A4的1.51倍.等离子体-质谱(ICP/MS)测得每分子含硒抗体酶分子中大约存在2个硒原子.mHB5的最适pH为8.6～8.8.在pH值范围为7.0和37℃条件下,mHB5催化GSH和H₂O₂或t-ROOH反应的二级速率常数为:_k+1(H₂O₂)9.71×10⁶L/(mol·min),_k+1(t-ROOH)5.99×10⁵L/(mol·min).mHB5使非酶催化反应速率提高了9.8×10⁶和3.7×10⁵倍.     

抗人乳腺癌糖蛋白单克隆抗体及相应抗原免疫反应的电化学阻抗 免疫分析研究

报道了一种用于抗人乳腺癌糖蛋白单克隆抗体(GP1D8)及相应抗原免疫反应的电化学阻抗免疫分析法。本方法采用将抗体直接定向组装到石英晶片/金电极上,实验中设计的阻抗传感测量只响应免疫信号。结果显示,当组装单克隆抗体的金电极被插入特殊抗原的溶液中时,电化学阻抗谱(EIS)发生明显的变化,成功地检测了组装抗体和相应抗原的免疫反应。     

酶联放大镧系螯合物发光法─辣根过氧化物酶(HRP)－铽－对羟基苯甲酸体系的研究及用于HRP和结核抗体的分析

酶联放大镧系螯合物发光法──辣根过氧化物酶（ＨＲＰ）－铽－对羟基苯甲酸体系的研究及用于ＨＲＰ和结核抗体的分析谢剑炜,鄢远,彭学军,许金钩,陈国珍（厦门大学化学系、现代分析化学研究所,厦门,３６１００５）关键词酶联放大镧系螯合物发光法,辣根过氧化物酶,...     

放射性核素标记单克隆抗体的化学研究进展

研究用放射性核素标记单克隆抗体作为肿瘤的导向药物,是核药物化学领域的研究热点.本文从化学角度介绍了单克隆抗体标记技术发展的概况,包括核素的选择,标记的方法,抗体的偶联修饰以及提高肿瘤/正常组织比的方法。     

A Novel Affinity Support Material for the Separation of Immunoglobulin G from Human Plasma

2‐Methacrylamidohistidine (MAH) as a pseudospecific ligand was synthesized from methacryl chloride and histidine. Spherical beads with an average size of 50–63 μm were obtained by the radical suspension polymerization of MAH and 2‐hydroxyethyl methacrylate (HEMA) conducted in an aqueous dispersion medium. Owing to the reasonably rough character of the bead surface, P(HEMA‐co‐MAH) beads had a specific surface area of 17.6 m²·g^–1. Synthesized MAH was characterized by NMR. P(HEMA‐co‐MAH) beads were characterized by swelling studies, FT‐IR spectroscopy, scanning electron microscopy (SEM) and elemental analysis. P(HEMA‐co‐MAH) affinity beads with a swelling ratio of 65% were used in the separation of human immunoglobulin G (HIgG) from aqueous solutions and human plasma. The maximum HIgG adsorption on the P(HEMA‐co‐MAH) adsorbents was observed at pH 7.4 for phosphate and at pH 6.0 for morpholinoethanesulfonic acid buffers. The HIgG adsorption onto the PHEMA adsorbents was negligible. Higher adsorption values (up to 46.5 mg·g^–1) were obtained when the P(HEMA‐co‐MAH) adsorbents were used in aqueous solutions. Much higher amounts of HIgG were adsorbed from human plasma (up to 73.8 mg·g^–1). Adsorption capacities of other blood proteins were obtained as 3.2 mg·g^–1 for fibrinogen and 4.6 mg·g^–1 for albumin. The total protein adsorption was determined to be 82.2 mg·g^–1. The pseudospecific affinity beads allowed one‐step separation of HIgG from human plasma. HIgG molecules could be repeatedly adsorbed and desorbed with these adsorbents without noticeable loss in their HIgG adsorption capacity.