A comparison study on structure-function relationship of polysaccharides obtained from sea buckthorn berries using different methods:antioxidant and bile acid-binding capacity

In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.

Preliminary Investigation of Copper(II) Ion Binding or Complex Coordination in Lysozeme Molecules

Hydrophobic Val derivative Schiff base copper(II) complexes and dipeptide (AlaAla, GlyGly) derivative Schiff base copper(II) complexes were introduced into egg white lysozyme. X-ray crystal structure analysis revealed amino acid derivative Schiff base copper(II) complexes were obtained. Herein we discuss primarily on the binding mode of copper(II) of the complexes obtained with egg white lysozyme. The electron density of copper(II) ions was confirmed by X-ray crystal structure analysis. The Val derivative Schiff base copper(II) complex was weakly bound at Arg114 of egg white lysozyme. In other copper(II) complexes, binding of copper(II) ions with dissociated ligands to various residues was observed. The binding sites of copper(II) ions were compared with computational scientific predictions.

Label-Free and Real-Time Monitor of Binding and Dissociation Processes between Protein A and Swine IgG by Oblique-Incidence Reflectivity Difference Method

Life science has a need for detection methods that are label-free and real-time. In this paper, we have selected staphylococcal protein A （SPA） and swine immunoglobulin G （IgG）, and monitor the bindings between SPA and swine IgG with different concentrations, as well as the dissociations of SPA-swine IgG complex in different pH values of phosphate buffer by oblique-incidence reflectivity difference （OIRD） in a label-free and real-time fashion. We obtain the ON and OFF reaction dynamic curves corresponding to the bindings and dissociations of SPA and swine IgG. Through our analysis of the experimental results, we have been able to obtain the damping coefficients and the dissociation time of SPA and swine IgG for different pH values of the phosphate buffer. The results prove that the OIRD technique is a competing method for monitoring the dynamic processes of biomolecule interaction and achieving the quantitative information of reaction kinetics.

Identification of highly conserved domains in hemagglutinin associated with the receptor binding specificity of influenza viruses: 2009 H1N1, avian H5N1, and swine H1N2

The hemagglutinin (HA) of influenza viruses facilitates receptor binding and membrane fusion, which is the initial step of virus infection. Human influenza viruses preferentially bind to receptors with α2-6 lin- kages to galactose (SAα2,6Gal), whereas avian influenza viruses prefer receptors with α2-3 linkages to galactose (SAα2,3Gal). The current 2009 H1N1 pandemic is caused by a novel influenza A virus that has its genetic materials from birds, humans, and pigs. Its pandemic nature is characterized clearly by its dual binding to the α2-3 as well as α2-6 receptors, because the seasonal human H1N1 virus only binds to the α2-6 receptor. In a previous study, the informational spectrum method (ISM), a bioinformatics technique, was applied to uncover one highly conserved region in the HA protein associated with receptor binding preference in each of various influenza subtypes. In the present study, we extended the previous work by discovering multiple such domains in HA of 2009 H1N1 and avian H5N1 to expand our repertoire of known key regions in HA responsible for receptor binding affinity. Three such domains in HA of 2009 H1N1 were found at residue positions 106 to 130, 150 to 174, and 191 to 221, and another three domains in HA of avian H5N1 were located at residue positions 46 to 65, 136 to 153, and 269 to 286. These identified domains could be utilized as therapeutic and diagnostic targets for the prevention and treatment of influenza infection.

Highly conserved domains in hemagglutinin of influenza viruses characterizing dual receptor binding

The hemagglutinin (HA) of influenza viruses in itiates virus infection by binding receptors on host cells. Human influenza viruses preferenti ally bind to receptors with α2,6 linkages to gala ctose, avian viruses prefer receptors with α2,3 linkages to galactose, and swine viruses favor both types of receptors. The pandemic H1N1 2009 remains a global health concern in 2010. The novel 2009 H1N1 influenza virus has its ge netic components from avian, human, and sw ine viruses. Its pandemic nature is characterized clearly by its dual binding to the α2,3 as well as α2,6 receptors, because the seasonal human H1N1 virus only binds to the α2,6 receptor. In pr evious studies, the informational spectrum me thod (ISM), a bioinformatics method, was appli ed to uncover highly conserved regions in the HA protein associated with the primary receptor binding preference in various subtypes. In the present study, we extended the previous work by discovering multiple domains in HA associa ted with the secondary receptor binding prefer ence in various subtypes, thus characterizing the distinct dual binding nature of these viruses. The domains discovered in the HA proteins were mapped to the 3D homology model of HA, which could be utilized as therapeutic and diag nostic targets for the prevention and treatment of influenza infection.

Receptor binding specificity and origin of 2009 H1N1 pandemic influenza virus

Recently, a genetic variant of 2009 H1N1 has become the predominant virus circulating in the southern hemisphere, particularly Australia and New Zealand, and in Singapore during the winter of 2010. It was associated with several vaccine breakthroughs and fatal cases. We analyzed three reported mutations D94N, N125D, and V250A in the HA protein of this genetic variant. It appeared that the reason for D94N and V250A to occur in pairs was to maintain the HA binding to human type receptor, so the virus could replicate in humans efficiently. Guided by this interpretation, we discovered a new mutation V30A that could compensate for N125D as V250A did for D94N. We demonstrated that the presence of amino acids 30A and 125N in HA enhanced the binding to human type receptor, while 30V and 125D favored the receptors of avian type and of A/South Carolina/1/18 (H1N1). Furthermore, a combination of 94D, 125D, and 250V made the primary binding preference similar to that of A/South Carolina/1/18 (H1N1) and a combination of 94N, 125D, and 250A resulted in the primary binding affinity for avian type receptor, which clearly differed from that of A/California/07/2009 (H1N1), a strain used in the vaccine for 2009 H1N1. We also re-examined the origin of 2009 H1N1 to refine our knowledge of this important issue. Although the NP, PA, PB1, and PB2 of 2009 H1N1 were closest to North American swine H3N2 in sequence identity, their interaction patterns were closest to swine H1N1 in North America.

Size dependence of biexciton binding energy in single InAs/GaAs quantum dots

This paper studies the size dependence of biexciton binding energy in single quantum dots （QDs） by using atomic force microscopy and micro-photoluminescence measurements. It finds that the biexciton binding energies in the QDs show ＂binding＂ and ＂antibinding＂ properties which correspond to the large and small sizes of QDs, respectively. The experimental results can be well interpreted by the biexciton potential curve, calculated from the exciton molecular model and the Heitler London method.

Quantifying the effects of mutations on receptor binding specificity of influenza viruses

Hemagglutinin (HA) of influenza viruses is a cylindrically shaped homotrimer, where each monomer comprises two disulfide-linked subdomains HA1 and HA2. Influenza infection is initiated by binding of HA1 to its host cell receptors and followed by the fusion between viral and host endosomal membranes mediated by HA2. Human influenza viruses preferentially bind to sialic acid that is linked to galactose by an α2,6-linkage (α2,6), whereas avian and swine influenza viruses preferentially recognize α2,3 or α 2,3/α2,6. For animal influenza viruses to cross host species barriers, their HA proteins must acquire mutations to gain the capacity to allow human-to-human transmission. In this study, the informational spectrum method (ISM), a bioinformatics approach, was applied to identify mutations and to elucidate the contribution to the receptor binding specificity from each mutation in HA1 in various subtypes within or between hosts, including 2009 human H1N1, avian H5N1, human H5N1, avian H1N1, and swine H1N2. Among others, our quantitative analysis indicated that the mutations in HA1 of 2009 human H1N1 collectively tended to reduce the swine binding affinity in the seasonal H1N1 strains and to increase that in the pandemic H1N1 strains. At the same time, they increased the human binding affinity in the pandemic H1N1 strains and had little impact on that in the seasonal H1N1 strains. The mutations between the consensus HA1 sequences of human H5N1 and avian H5N1 increased the avian binding affinity and decreased the human binding affinity in avian H5N1 while produced the opposite effects on those in human H5N1. Finally, the ISM was employed to analyze and verify several mutations in HA1 well known for their critical roles in binding specificity switch, including E190D/G225D in H1N1 and Q192R/ S223L/ Q226L/ G228S in H5N1.

CRP Binding Kinetics Enhancement Using Local Narrowing into a Bent Channel: Finite Element Analysis

Binding kinetics enhancement of a microfluidic biosensor into a micro-channel through the application of a supplementary mechanism has received tremendous attention because of the obtained significant enhancement factor. However, biosensor’s performance enhancement using only simple channel engineering is still rarely realized. Herein, we present a novel design of a complex reactive protein (CRP) biosensor into a U-shaped channel with a sensitive membrane located in the middle of the bent zone. Various critical factors affecting the equilibrium binding time are numerically investigated. The turn geometry is then optimized when the arc length along the inner and outer radii is almost the same, which leads to locally minimizing the channel height overhead the reaction surface and improves the analyte transport towards the sensing area. The numerical studies reveal that applying a local narrowing above the reaction surface can notably enhance the trapping and the surface formation of complex antibody-antigen, thus upgrading the biosensor performance. This work puts a significant advance towards microfluidic channel engineering and the exploration of micro-flow injection experimental studies.

基于调肝疏情法治疗肝气郁结型耳鸣

探讨基于调肝疏情法,以电针晕听区联合身心干预治疗肝气郁结型耳鸣的临床应用。肝气郁结型耳鸣源于情志不遂,肝气郁结,气机阻滞,阴阳升降失调而致耳鸣,治疗上应调肝疏情。电针晕听区可疏肝清窍、调和气血,身心干预治疗可调畅情志、平衡阴阳,二者联合共克耳鸣之难症。临床运用过程中,因其安全便捷,亦可根据患者不同伴随症状进行灵活加减,收效颇优。

“Grafting from”法制备高载量大孔弱阳离子交换层析介质

针对大孔聚合物层析介质孔径大、比表面积低而导致的蛋白结合容量低的问题,采用“graftingfrom”策略,以大孔聚丙烯酸酯微球为基质,通过氧化还原引发甲基丙烯酸在微球表面接枝聚合,制备了高载量弱阳离子交换层析介质.研究了单体浓度、过硫酸钾浓度及反应温度等因素对蛋白结合容量的影响.所得介质的蛋白静态结合容量和动态结合容量分别达到252.21和157.25mg/mL;同时发现具有一定离子交换容量的该类介质能够在0.2 mol/L NaCl缓冲液中保持100 mg/mL的蛋白结合容量.将该层析介质用于鸡卵清中溶菌酶的纯化,获得了较高的纯化效率.

硼磷烯量子点的电子结构和光学性质研究

采用紧束缚近似方法对锯齿状六边形硼磷烯量子点在平面电场和垂直磁场调控下的电子结构和光学性质进行了研究.研究表明,硼磷烯量子点作为直接带隙半导体,在无外加电场和磁场作用时,能隙不随尺寸的改变而变化.在平面电场调控下,能隙随电场强度的增加逐渐减小直至消失,平面电场方向几乎不会对硼磷烯量子点体系产生影响,且随量子点尺寸的增大,能隙消失所需电场强度逐渐减小.在垂直磁场调控下,表现为体态的能级在磁场作用下形成朗道能级,而能隙边缘处的朗道能级近似为一个平带,不随磁通量的改变而变化,态密度主要分布于朗道能级处.另外,垂直磁场作用下的光吸收主要是由朗道能级之间的跃迁引起的.

Study on State of Terbium Ion in Liposome by One order Derivative Fluorescence Quenching Method

The state of Tb3+ is investigated in liposome. When the concentration of PC is below CMC (critical micell concentration), most of Tb3+ is associated with PC, the binding constant is about 3.35×103 L/mol. When the concentration of PC is beyond CMC, most of Tb3+ is dimerized, the dimerization constant is about 3.92×104L/mol. In PC?CH?H2O system, the binding constant of Tb3+?CH complex 2.93×104L/mol is obtained.

人干扰素α2b ELISA配体结合分析检测方法的建立

目的:建立金黄地鼠血浆和组织重组人干扰素α2b定量ELISA检测法,用于药物研发检测。方法:采用双抗夹心法建立金黄地鼠血浆和组织重组人干扰素α2b含量检测方法,确定其检测范围,验证其选择性、精密度与准确度和稀释线性,并对样本稳定性进行研究。结果:建立的方法检测范围为0.50~16.00 ng/ml。选择性结果显示不同个体来源空白金黄地鼠组血浆和组织匀浆无差异,血浆质控样本准确度为78.62%~104.69%,批内精密度为0.69%~18.21%,批间精密度为6.71%~15.81%,总误差均<30%,稀释线性良好。稳定性样本在3种不同保存条件(冰上放置2 h;−80~−75℃放置4 d;反复冻融3循环)下稳定性较好,回收率均在±20%内。结论:成功建立了基于配体结合的人干扰素α2b ELISA检测法,该方法灵敏度高,重复性好,检测效率高,为新药研发提供了可靠的检测方法。

类紫杉醇脂质体体外释放的桨膜结合分析法研究

体外释放度是评价脂质体制剂质量的重要指标,目前各国药典中均未收载脂质体体外释放度评价方法,致使脂质体质量评价缺乏统一标准和无法提供安全性保障。本研究以自制类紫杉醇脂质体为例,通过优化外部释放条件建立的桨膜结合法模拟了在生理条件下类紫杉醇药物12 h的释放情况,结果表明以0.5%SDS-HEPES作为释放介质,采用截留分子量为1000 kD的透析袋对脂质体水溶液进行释放的结果满足要求,且具有区分能力,为载药脂质体体外释放方法开发提供参考。

1英寸CsPbCl_(3)晶体的生长及其发光性能研究

CsPbX_(3)(X=Cl^(-), Br^(-), I^(-))钙钛矿单晶具有优异的光电性能,有望成为下一代光电探测材料。由于CsCl在前驱体中的溶解度过小,通过低温溶液法较难生长得到CsPbCl_(3)晶体。本工作采用坩埚下降法成功生长了1英寸完整的CsPbCl_(3)晶体,并对晶体进行了一系列加工,得到了ϕ10 mm×10 mm和厚度为2 mm的单晶片。测试了晶体的X射线粉末衍射图谱、TG/DTA曲线、X射线激发发射光谱、透过光谱和低温荧光光谱。在X射线的激发下,在430和575 nm观察到两个X射线激发发射峰,晶体的透过率达到75%;光致发光(PL)强度与温度依赖性曲线中可以观察到热猝灭现象,计算得到晶体4个峰的激子结合能分别为12.59、8.21、12.41和21.59 meV。

猪流行性腹泻病毒感染小鼠血清抗体间接ELISA方法的建立

为建立检测感染小鼠血清中猪流行性腹泻病毒(PEDV)抗体的方法,本研究应用PEDV受体结合区(receptor binding domain, RBD)重组蛋白作为抗原,通过探索各反应的最佳条件,并进行了该方法灵敏度、重复性、特异性分析。结果显示,最佳蛋白包被浓度为5μg/mL,待检血清稀释浓度为1∶400,孵育时间为37℃30 min,羊抗鼠IgG-HRP作为二抗,孵育条件为37℃30 min,底物显色时间为15 min。对建立的ELISA检测方法进行验证,阳性对照血清的稀释度为1∶204 800倍时OD450值仍大于临界值,批内和批间的变异系数均小于10%,对猪传染性胃肠炎病毒和猪δ冠状病毒抗体小鼠阳性血清检测均不发生交叉反应。结果表明本研究建立的小鼠血清PEDV抗体间接ELISA方法具有很好的灵敏度、重复性、特异性。为PEDV候选疫苗的小鼠血清特异性抗体检测提供了一种精准、高效的方法。

彰往察来,显微阐幽:论日本札甲编缀技法源流与发展

日本札甲编缀技法作为日本传统铠甲至关重要的部分,研究其源流与发展对拓宽东亚铠甲史具有重要意义。本文通过对历史文献与文物资料的考据,将各个时期日本札甲编缀技法进行分解,并对其演变发展路径加以梳理归纳,阐述不同时代背景下札甲编缀技术转徙的渐次发展。通过研究表明:日本古坟时代挂甲起源是来自于中国东北地区骑兵甲的技术输入,后在素悬威技法上走向本土技术的革新;日本札甲编缀的发展路向是在多重潜在交流与冲突下断续递进的过程;在近世西学东渐的文化协同下,日本札甲的技术与艺术走向了巅峰时代。