名词浅释

<正> 量子生物学主要研究生物分子间的相互作用力、分子的电子结构及其反应活性、分子的空间构型和生物分子间的特异作用与识别机制等的一种边缘科学。对于阐明某些生命过程具有非常重要的意义。过去被称为“亚分子生物学”,     

太空诱变对链球菌菌体多糖分子表达的影响

目的研究太空诱变对α-溶血性链球菌多糖分子表达的影响。方法采用改良的过碘酸钠法将辣根过氧化物酶(HRP)分别标记在刀豆凝集素(ConA)、麦胚凝集素(WGA)、接骨木凝集素(SNA)、蓖麻凝集素Ⅰ(RCA-Ⅰ)及植物血凝素(PHA)上,合成HRP-凝集素,检测普通型α-溶血性链球菌及太空型链球菌菌体内多糖分子的表达水平。结果太空型链球菌菌体内末端为ConA、SNA及RCA-Ⅰ所识别的多糖分子含量较普通型α-溶血性链球菌高,且差异有统计学意义;末端为WGA及PHA所识别的多糖分子含量,普通型α-溶血性链球菌较太空型链球菌稍高,但差异无统计学意义。结论太空诱变对细菌的多糖分子表达具有调控作用,为细菌多糖制品的筛选及其性能和产量的提高提供了新的途径。     

糖基环糊精衍生物的合成及其生物应用研究进展

糖蛋白能够识别糖簇分子,将其连接到具有空腔的环糊精上,通过糖蛋白与环糊精上特殊糖分子间的识别作用可将糖基环糊精衍生物包结的药物分子传递到指定的生物受体中,从而使糖基环糊精衍生物具有药物靶向性.综述了近年来糖基环糊精衍生物的合成及其生物应用研究进展.     

分子钳化学研究的新进展

分子钳化学是当今化学学科研究的热点之一.介绍了分子钳化合物的结构、应用及新进展,重点综述了分子钳化合物的合成、分子钳对手性分子及阴离子的识别作用、分子钳对中性分子的识别作用,并对其应用前景进行了展望,期望能在医药学、生命科学、材料科学、环境科学、分子器件、生物传感器、仿生催化及分析分离科学中得到更广泛的应用.     

生物矿化及仿生矿化中的信息传递和转化

牙齿、骨骼、贝壳等生物矿物具有多级有序的结构和优异的力学性能,是生物矿化过程调控下的矿化结晶产物。生物矿化中的矿物与生物有机基质之间的界面分子识别和结晶调控策略为深入理解化学工程中的“信息传递和转化”范式提供了良好的学习素材。以生物矿化典型无机矿物磷酸钙和碳酸钙体系为例,从生物矿物-溶液界面结构、生物分子与矿物晶面的分子识别、矿物结晶调控三个层面综述了生物矿化的化学调控原理,并从信息传递和转化的化学工程范式出发,分析了生物矿化中分子工程和结晶调控策略。绿色高效的生物矿化过程调控策略有望应用于未来化学工程以解决目前面临的需求倍增和资源短缺的全球性问题。     

芦荟凝集素的理化性质及其对动物细胞生长的影响

对分别从中华芦荟、库拉索芦荟和木立芦荟叶肉组织中分离提取得到的 3种凝集素 (命名为Lec1、Lec2和Lec3)进行了理化性质的比较研究 ,考察了三者的分子质量 ,对糖抑制的专一性和糖基组成。结果表明Lec1和Lec3的相对分子质量为2 3 0 0 0 ,而Lec2为 2 6 0 0 0 ,只有Lec3能被麦芽糖抑制。糖基组成分析结果表明 ,三者的糖链部分主要由甘露糖、葡萄糖和N 乙酰氨基葡萄糖构成。三种芦荟凝集素能够识别并抑制K562乳腺癌细胞的生长 ,中华凝集素、库拉索凝集素、木立凝集素的抑瘤率IC50值分别为 4 1 93、2 30 5、1 41 8mg/ml。而在质量浓度 >2 5mg/ml时它们对成纤维细胞FC的生长有一定的促进作用。动物体内实验进一步证实了芦荟凝集素的抑瘤作用 ,同时表明芦荟凝集素能够激发机体的免疫功能来抵御癌细胞的入侵     

基于静电结合的电化学阻抗D-甘露糖生物传感器的研究

糖组学的研究已经成为后基因时代一个重要的研究领域.糖类物质与凝集素之间的特异性相互作用,能够用于制备糖生物传感器,文章设计了一种简便的D-甘露糖电化学阻抗生物传感器,以刀豆凝集素为分子识别物质,静电吸附法将刀豆凝集素固定到金圆盘电极的表面,用电化学阻抗法进行检测.实验结果表明,以[Fe（CN）6]3-4-氧化还原电对作为探针,电子转移阻抗变化值与D-甘露糖浓度的对数在5.0×10-8～1.0×10-5 mol/L之间呈良好的线性关系,检出限为0.02μmol/L.     

香豆素基金属-有机笼对氨基葡萄糖的识别

将发光性质优异的香豆素基团作为荧光信号单元引入有机配体H3L,与过渡金属离子Zn(Ⅱ)配位自组装,构建了一例金属-有机笼状化合物Zn-L,利用主客体氢键弱作用实现了对氨基葡萄糖的选择性识别.高分辨质谱和紫外-可见吸收光谱结果显示,金属-有机笼状化合物Zn-L结构可能为M6L4的八面体构型,12个香豆素基团均匀分布在笼状结构的顶点,空腔带有窗口,允许尺寸合适的客体分子自由进出.主客体核磁滴定显示,氨基葡萄糖通过多重氢键作用与笼状结构相结合;高分辨质谱测试表明,笼状结构与氨基葡萄糖形成了物质的量比为1:2的主客体包合物.荧光滴定光谱拟合结果显示,络合常数为1.6×108 L2/mol2,证实主客体间具有较强的络合作用,有利于笼状结构对氨基葡萄糖的选择性识别.氨基葡萄糖分子对Zn-L荧光强度淬灭高达93％,最低检测限为0.23μmol/L,而其他9种常见生物糖类小分子只能淬灭5％～20％,Zn-L对氨基葡萄糖分子具有选择性荧光响应,且可以应用于活细胞中氨基葡萄糖的荧光成像.     

花菁类近红外荧光探针在生物检测中的应用研究进展

随着现代生物学和生物技术的发展,近红外荧光探针作为一种重要的技术手段在许多领域都展现出了重要的应用价值。因具有背景干扰低、细胞损伤小、样品穿透性强、检测灵敏度高等优点,经常用于分子识别、医学诊断、生物分子检测以及生物成像等方面。本综述从金属离子检测、含硫小分子检测、活性氧（ROS）/活性氮（RNS）检测、酶识别、肿瘤细胞识别及治疗以及细胞内pH响应等方面,介绍了近年来花菁类荧光探针在生物检测中的应用研究进展。同时指出了花菁类荧光探针亟待解决的问题,通过花菁母体的结构修饰和改造提高探针的光稳定性、灵敏度、靶向性和水溶性,有望使其在生物检测以及疾病的诊断方面得到进一步应用发展。     

亲和色谱在医药生物中的应用

亲和色谱(亲和层析)是利用了生命现象中生物分子之间非常特异的相互作用，而十分巧妙的进行分离纯化的方法。生物体内生物分子之间，如酶与底物，酶与抑制剂，酶与变构效应剂，酶与辅酶，激素与细胞受体，维生素与结合蛋白，基因与核酸，抗体与抗原，外源凝集素与红血球表面上的抗原等，都相互具有亲和力，能形成可逆的络合物，亲和色谱就是利用这种可逆络合物结合与解离的原理而发展起来的新的纯化技术。     

Human Macrophage Galactose-Type Lectin (MGL) Recognizes the Outer Core of Escherichia coli Lipooligosaccharide

Carbohydrate–lectin interactions intervene in and mediate most biological processes, including a crucial modulation of immune responses to pathogens. Despite growing interest in investigating the association between host receptor lectins and exogenous glycan ligands, the molecular mechanisms underlying bacterial recognition by human lectins are still not fully understood. Herein, a novel molecular interaction between the human macrophage galactose-type lectin (MGL) and the lipooligosaccharide (LOS) of Escherichia coli strain R1 is described. Saturation transfer difference NMR spectroscopy analysis, supported by computational studies, demonstrated that MGL bound to the purified deacylated LOS_R1 mainly through recognition of its outer core and established crucial interactions with the terminal Galα(1,2)Gal epitope. These results assess the ability of MGL to recognise glycan moieties exposed on Gram-negative bacterial surfaces.     

查尔酮类化合物药理作用研究进展

对查尔酮类化合物的研究进展做了较为详细的综述。查尔酮类化合物的有广泛的药理作用,对其结构与药理作用的关系进行深入研究,为寻找治疗多种疾病的新药提供理论依据。     

Molecular Recognition in C-Type Lectins: The Cases of DC-SIGN,Langerin, MGL,and L-Sectin

Carbohydrates play a pivotal role in intercellular communication processes. In particular, glycan antigens are key for sustaining homeostasis, helping leukocytes to distinguish damaged tissues and invading pathogens from healthy tissues. From a structural perspective, this cross-talk is fairly complex, and multiple membrane proteins guide these recognition processes, including lectins and Toll-like receptors. Since the beginning of this century, lectins have become potential targets for therapeutics for controlling and/or avoiding the progression of pathologies derived from an incorrect immune outcome, including infectious processes, cancer, or autoimmune diseases. Therefore, a detailed knowledge of these receptors is mandatory for the development of specific treatments. In this review, we summarize the current knowledge about four key C-type lectins whose importance has been steadily growing in recent years, focusing in particular on how glycan recognition takes place at the molecular level, but also looking at recent progresses in the quest for therapeutics.     

聚羧(磺)酸系高性能减水剂作用机理及分子结构设计

综述了聚羧(磺)酸系高性能减水剂作用机理,讨论了作用机理与分子主、支链基团之间的关系;从分子单元结构出发,提出了高性能减水剂分类方法,指出了未来减水剂研究方向。     

Flows of dilute hydrolyzed polyacrylamide solutions in porous media under various solvent conditions

Experimental results on pressure losses of flows of dilute polymer solutions through porous media are summarized. The polymer products employed in this study consisted of partially hydrolyzed polyacrylamides (HPAM) with different degrees of hydrolysis. The effect of the hydrolysis on the pressure drop is investigated in a porous media test section designed to minimize polymer degradation. The investigations were carried out for various solvent conditions, and it is shown that the maximum increase in pressure drop is mainly dependent on the molecular weight of the polymers. The onset of the polymer action is measured for various fluid and solvent properties. Particular attention is given to measurements near θ-conditions. The results stress the importance of the solvent properties on the actions of the polymers and on the resultant pressure drop for porous media flows. The addition of salt ions to solutions of partially hydrolyzed polyacrylamides yields onset behavior previously observed for nonionic polymers. The differences measured between various solvent properties can be explained by the actual hydrodynamic molecule dimensions for a given molecular weight and polymer concentration. To quantify the influences of the solvent properties on the polymers, measurements were carried out in aqueous solutions for various pH values and therefore at various degrees of dissociation. The importance of separating polymer effects caused by their linear dimension in the solution from those that are introduced by and increase in solvent viscosity is shown. Measurements were performed to quantify the effects of solvent viscosity on the polymer action and to separate these effects from those due to changes in molecule dimensions. The implications of the present results are stressed in connection with applications of polymer solutions in tertiary oil recovery, and the positive features of the molecule actions on flow in such applications are described.     

P(DMC-AM)高分子絮凝剂的制备及絮凝性能

论述了高相对分子质量阳离子聚(甲基丙烯酰氧乙基三甲基氯化胺-丙烯酰胺)〔P(DMC-AM)〕絮凝剂的制备及絮凝性能研究,讨论了多种因素对絮凝效果的影响。当w(单体)=40%;m(DMC)∶m(AM)=3∶2;m(引发剂)∶m(AM)=0.09∶100时,得到的阳离子型P(DMC-AM)高分子絮凝剂对造纸污水及生活废水有明显的絮凝作用。P(DMC-AM)的最佳絮凝条件为:相对分子质量为430~460万,用量为1.1~1.3 mg/L,阳离子度为33%~38%,废水pH=3~7;在造纸污(废)水体系中,CODC r的去除率可达89%以上,透光率接近100%;采用电子扫描电镜观察絮凝物,结果发现,絮凝后的纤维间可形成多个物理吸附点,交叉网状结构明显,网络编织致密,说明桥联及电中和作用明显,絮凝效果优异。     

Carbohydrate-protein interactions: a 3D view by NMR

This review focuses on the application of NMR methods for understanding, at the molecular and atomic levels, the diverse mechanisms by which sugar molecules are recognised by the binding sites of lectins, antibodies and enzymes. Given the intrinsic chemical natures of sugars and their flexibility, it is well established that NMR parameters should be complemented by computational methods in attempts to unravel the structural and conformational features of the molecular recognition process unambiguously. We therefore aim here to describe new and significant advances in the knowledge of carbohydrate-protein interactions, obtained by employing state-of-the-art NMR and molecular modelling. We have not attempted to prepare an exhaustive review but have tried to focus on describing the key aspects that should be considered when tackling a problem within this research topic.     

Systemic Lectin-Glycan Interaction of Pathogenic Enteric Bacteria in the Gastrointestinal Tract

Microorganisms, such as bacteria, viruses, and fungi, and host cells, such as plants and animals, have carbohydrate chains and lectins that reciprocally recognize one another. In hosts, the defense system is activated upon non-self-pattern recognition of microbial pathogen-associated molecular patterns. These are present in Gram-negative and Gram-positive bacteria and fungi. Glycan-based PAMPs are bound to a class of lectins that are widely distributed among eukaryotes. The first step of bacterial infection in humans is the adhesion of the pathogen’s lectin-like proteins to the outer membrane surfaces of host cells, which are composed of glycans. Microbes and hosts binding to each other specifically is of critical importance. The adhesion factors used between pathogens and hosts remain unknown; therefore, research is needed to identify these factors to prevent intestinal infection or treat it in its early stages. This review aims to present a vision for the prevention and treatment of infectious diseases by identifying the role of the host glycans in the immune response against pathogenic intestinal bacteria through studies on the lectin-glycan interaction.