植物修复富营养化水体分子机理的研究现状

植物修复富营养化水体具有成本低、效果好、简单易行、且可改善生态环境等优点,具有广阔的应用前景.高等水生植物在生长过程中能够大量吸收水体中的N,P等营养物质,同时释放化学物质,抑制浮游藻类生长,从而达到净化水体的效果.在此主要从分子水平介绍了植物去除富营养化水体中N,P的作用机理.     

Combined fluorescence and electrochemical investigation on the binding interaction between organic acid and human serum albumin

Human serum albumin (HSA) is a plasma protein responsible for the binding and transport of fatty acids and a variety of exogenous chemicals such as drugs and environmental pollutants. Such binding plays a crucial role in determining the ADME (absorption, distribution, metabolism, and excretion) and bioavailability of the pollutants. We report investigation on the binding interaction between HSA and acetic acid (C2), octanoic acid (C8) and dodecanoic acid (C12) by the combination of site-specific fluorescent probe, tryptophan intrinsic fluorescence and tyrosine electrochemistry. Two fluorescent probes, dansylamide and dansyl-L-proline, were employed in the displacement measurement to study fatty acid interaction with the two drug-binding sites on HSA. Intrinsic fluorescence of tryptophan in HSA was monitored upon addition of the fatty acids into HSA. Electrocatalyzed response of the tyrosine residues in HSA by a redox mediator was used to investigate the binding interaction. Qualitatively, observations made by the three approaches are very similar. HSA did not show any change in either fluorescence or electrochemistry after mixing with C2, suggesting there is no significant interaction with the short-chain fatty acid. For C8, the measured signal dropped in a single-exponential fashion, indicative of independent and non-cooperative binding. The calculated association constant and binding ratio is 3.1×106 L/mol and 1 with drug binding Site I, 1.1×107 L/mol and 1 with Site II, and 7.0×104 L/mol and 4 with the tryptophan site. The measurement with C12 displayed multiple phases of fluorescence change, suggesting cooperativity and allosteric effect of C12 binding. These results correlate well with those obtained by the established methods, and validate the new approach as a viable tool to study the interactions of environmental pollutants with biological molecules.     

Synthesis, characterization, and adsorption performance of Pb（Ⅱ）-imprinted polymer in nano-TiO2 matrix

Surface ion-imprinted in combination with sol-gel process was applied to synthesis a new Pb(II)-imprinted polymer for selective separation and enrichment of trace Pb(II) from aqueous solution. The prepared material was characterized by using the infrared spectra, X-ray di ractometer, and scanning electron microscopy. The batch experiments were conducted to study the optimal adsorption condition of adsorption trace Pb(II) from aqueous solutions on Pb(II)-imprinted polymer. The equilibrium was achieved in approximately 4.0 h, and the experimental kinetic data were fitted the pseudo second-order model better. The maximum adsorption capacity was 22.7 mg/g, and the Langmuir equation fitted the adsorption isotherm data. The results of selectivity experiment showed that selectively adsorbed rate of Pb(II) on Pb(II)-imprinted polymer was higher than all other studied ions. Desorption conditions of the adsorbed Pb(II) from the Pb(II)-imprinted polymer were also studied in batch experiments. The prepared Pb(II)-imprinted polymer was shown to be promising for the separation and enrichment of trace Pb(II) from water samples. The adsorption and desorption mechanisms were proposed.     

Selective removal of 2,4-dichlorophenoxyacetic acid from water by molecularly-imprinted amino-functionalized silica gel sorbent

A molecularly-imprinted amino-functionalized sorbent for selective removal of 2,4-dichlorophenoxyacetic acid(2,4-D) was prepared by a surface imprinting technique in combination with a sol-gel process.The 2,4-D-imprinted amino-functionalized silica sorbent was characterized by FT-IR,nitrogen adsorption and static adsorption experiments.The selectivity of the sorbent was investigated by a batch competitive binding experiment using an aqueous 2,4-D and 2,4-dichlorophenol(2,4-DCP) mixture or using an aqueous 2...     

电化学发光、分子印迹技术及其结合技术分析

电化学发光是一种不需要外加激发光源,而且背景信号低,线性范围宽,不需要昂贵设备的方法.分子印迹却是一种具有高度识别性和选择性的新技术.通过结合两者,可制备出具有选择性好、灵敏度高、检测限低、易于操作等特点的分子印迹-电化学发光传感器.近年来,在有毒有害物质、残留农药、药物质量检测以及生物传感器制备等多领域具有广泛的应用.本综述简要介绍电化学发光、分子印迹技术以及分子印迹-电化学发光传感器的应用概况,为今后的检测技术提供了一种新方法.     

石墨探针采样/石墨探针炉原子吸收光谱测定APM中痕量铜

采用一定规格的石墨探针可直接收集大气微料物质（ＡＰＭ）。然后,立即采用石墨探针炉原子吸收光谱测定收集在探针上的ＡＰＭ中痕量铜。方法简便,快速。在０－５５０ｎｇ／ｍＬ范围内,铜的浓度与峰面积吸光度呈良好的线性关系。铜的特征量为２２．０ｐｇ,检出限为６．６ｎｇ／ｍＬ。分析标准参比材料,铜的回收率达９８％,相对标准偏差为３．３％。     

石墨探针收集/石墨探针炉原子吸收法直接测定APM中痕量铅

研究一种直接收集并测定大气微粒物质中痕量有害元素铅的新方法,石墨探针直接收集ＡＰＭ后,用石墨探针炉原子吸收法直接测定收集在探针上的ＡＰＭ中痕量铅。方法特征量为４４．００ｐｇ,检出限为４８．３６ｐｇ,,相对标准偏差为３．２２％,铅学度与峰面积吸光度在０－２５０μｇ／Ｌ范围内呈线性关系,测定标准参比材料,其回收率为９４．４２％＿９９．１４％,并成功地测定了大气微粒物质中痕量铅的含量。     

饮用水中有机污染物分子的VRML模型

用半经验量子化学计算MNDO-PM3方法,计算了腐殖酸(HA)和3-氯-4-(二氯甲基)-5一羟基-2(5H)-呋喃酮(MX)的几何构型、电子结构等．用MolSurf软件建立了HA和MX的VRML(虚拟现实造型语言)模型．     

环境污染物的分子毒理机制研究进展

以分子生物学技术为基础研究污染物的毒理机制．从分子水平揭示了污染物毒作用的本质。综述了国内外分子毒理机制的研究进展。详细阐述了毒理芯片、单细胞凝胶电泳等分子生物学技术应用与毒理学研究中的特点、应用前景以及存在的问题。提出了分子毒理机制今后的研究方向。     

红球菌酰胺酶降解阴离子型聚丙烯酰胺的亲和力分析

为探究酰胺酶降解阴离子型聚丙烯酰胺（HPAM）的微观机理,采用分子对接分别模拟了阴离子型聚丙烯酰胺（HPAM）或聚丙烯酸酯（PAA）结构模型与Rhodococcus sp. N-771酰胺酶（Rh Amidase）的结合,根据-CDOCKER＿Energy score值最高的原则,对获得最佳结合构象进行分析.基于亲和力虚拟突变进行丙氨酸（ALA）扫描.亲和力分析表明,Rh Amidase对HPAM-2的亲和力最高、最稳定,而Rh Amidase于PAA-2相互作用最小、结合最好.同时,该酶更倾向于降解短链的聚合物.相互作用分析表明,疏水相互作用是Rh Amidase-HPAM-2比Rh Amidase-PAA-2更稳定的主要原因.通过ALA扫描进一步得知,PHE146、ILE450、LYS96和GLY193是Rh Amidase降解HPAM-2的关键氨基酸残基.其中GLY193与HPAM-2形成的1个氢键对Rh Amidase-HPAM-2的亲和力影响最大.突变体ASP191ALA可以提高Rh Amidase对HPAM-2的酶活性,这些数据可为设计更高活性的Rh Amidase突变体提...