重金属离子的免疫检测研究进展

农畜产品中残留的重金属离子已对人类安全构成严重威胁,急需快速、高效的重金属残留检测方法。重金属离子免疫检测是一种新型的检测方法,与传统检测方法相比,具有省时、省力、费用低廉、便于携带、易于操作等优点。除了化学螯合剂之外,植物螯合肽和金属硫蛋白也可用来制备重金属免疫原。重金属离子的免疫检测可分为多克隆抗体免疫检测和单克隆抗体免疫检测,前者包括荧光偏振免疫检测,后者包括间接竞争性ELISA、一步法竞争性免疫检测和KinExA免疫检测。作为一种辅助方法,胶体金快速免疫层析法可初步检测样品中的重金属离子浓度。     

基于Fe_3O_4过氧化物酶活性的Cd~(2+)和Pb~(2+)比色传感器

重金属残留超标是重大食品安全问题之一。为建立一种快速简单的Cd~(2+)和Pb~(2+)重金属离子检测法,以磁性Fe_3O_4纳米粒子(MNPs)的过氧化物酶活性作为传感信号输出工具,以核酸适配体的特异性识别功能作为靶标识别元件,建立了一个比色传感器。通过可行性分析和条件优化确定检测方法,再通过灵敏度和特异性实验对传感器性能进行评估。在最优条件下,Cd~(2+)和Pb~(2+)的最低检测线分别为0.108μmol/L和0.117μmol/L。该检测方法检测成本低、检测过程快速简单、检测结果肉眼可见,凭借手持式光度计即可实现定量分析。此外,该方法受其他离子干扰相对较小,特异性较强。该传感器的建立将使重金属的现场实时快速检测成为可能,为我国食品安全检测提供了有力保障。     

兽药残留快速检测方法比较分析

兽药残留是动物性食品不合格的多发指标,因此食品中兽药残留快速检测技术逐渐成为当前人们关注的重点之一。本文中,笔者比较综述了常用的兽药残留快速检测技术,分别介绍了拉曼光谱技术、薄层色谱技术、免疫学技术、生物传感器技术和生物芯片技术等兽药残留快速检测技术的不足及优势,分析了兽药残留快检技术发展趋势,以期对今后兽药残留快速检测技术的发展具有一定的借鉴意义和指导作用。     

救护鳄蜥食物有害重金属和农药残留的检测北大核心CSCD

鳄蜥(Shinisaurus crocodilurus)为国家I级保护野生动物。近年来,我国广西大桂山鳄蜥国家级自然保护区北娄繁育基地救护的鳄蜥一直存在疾病困扰,但原因不明。为了探讨这些疾病的发生是否与其食物中的重金属及农药污染相关,本研究采用电感耦合等离子体质谱和色谱质谱分析技术来检测其主要食物中的重金属和农药残留含量。结果显示,与其食物(蚯蚓)相比,鳄蜥体内的重金属含量更低,同时,农药残留含量在鳄蜥及其食物中均未检测出,说明重金属和农药通过食物的生物放大作用而在鳄蜥体内累积的可能性较小。因此,重金属与农药这两类环境污染物对鳄蜥疾病发生的影响较小。本研究为鳄蜥的人工救护繁育工作提供一定的参考,有利于鳄蜥的保护工作。     

上海市常见养殖水产重金属残留与膳食风险评估

水产品是人类摄入重金属的重要来源之一。为检测上海市常见养殖水产品的重金属残留及其污染来源，并进行膳食风险评估，文章采用快速消解-电感耦合等离子体质谱法（inductively coupled plasma mass spectrometry,ICP-MS）测定水产品及其养殖环境中铅、镉、铬、汞、砷的含量；并使用单因子指数（single factor pollution index,Pi）、重金属污染指数（metal pollution index,MPI）、相关性分析和危害商数（hazard quotient,HQ）对水产品的金属残留现状、污染来源、膳食风险进行评估。结果表明，重金属污染程度依次为：蟹类>虾类>鱼类、青鱼>鲢鱼>鳙鱼>草鱼、底泥>饲料>养殖水。Pi结果显示，虽然饲料中的Cr、Pb、Cd超出了限量标准，但所有样品的污染均不明显。相关性分析结果显示，水产与饲料中Cr含量之间存在明显的相关性，与其他4种重金属不具相关性。膳食风险评估结果显示，水产品中5种重金属的HQ值均小于1，因此可认为摄入鱼类、甲壳类水产品不会给暴露人群带来明显的健...     

北京东郊作物对重金属的吸收及其与重金属在土壤中含量和存在形态的关系

重金属在环境中的残留、累积常常引起一些环境问题Schroeder,1965;Lewis,1969;Nandi,1969;Tsuchiya,1969;Friberg,1974。在植物土壤系统中,由于重金属被土壤强烈吸附和固定,很容易在土壤中残留累积,引起生长的植物吸收过多的重金属而造成对人体健康的威胁(Friberg,1974;Lagerwerff,1972;Lisk,1972;Page,1973;Page,     

检测重金属离子生物传感器的研究进展北大核心CSCD

重金属污染广泛存在于环境中,它能通过生物富集作用对动植物及人类产生危害。利用分析化学方法检测重金属离子对其生物危害缺乏直接检定,生物传感器检测重金属离子吸引了越来越多的研究兴趣。对检测重金属离子的各种生物传感器进行介绍,并分析各种生物传感器的特点,指出依靠先进的生物技术研究方法和成果、了解生物传感器生物敏感材料的结构和功能,进一步开发能够自动操作的便携生物传感器是能够满足重金属污染检测要求的方法。     

生物传感器:靶标物质快速检测面临的机遇与挑战

正在自然界中,各种类型的风险因子无时无刻不在对人类生命健康造成危害,同时一些风险因子的存在还严重制约了农业等产业的发展。例如,农药残留、重金属超标等风险因子对种植业造成危害;兽药残留、病原微生物及寄生虫对养殖业造成破坏。此外,在生物学和医学领域,一些特殊的生物标志物也同物种种间鉴别、疾病的早期诊断与治疗有着密切的联系。因此,实现对于这些种类广泛且特点不同的靶标物质的快速、精确检测对于保障人类生命健康、增加经济收入、提高生活质量具有十分重要的意义。     

抗重金属汞离子抗体的制备及鉴定

汞、镉、铅等重金属引起的环境污染已在世界范围内造成危害。快速、廉价地监测生境中重金属是减小其对人类及动物危害的先决条件。传统检测方法无法满足高通量的现场检测,建立更快速、更经济的免疫分析法检测汞离子是生产及经济发展的需要。本研究中,报道了汞特异性单克隆抗体的制备与筛选方法和结果。因Hg2+太小以至于不能引起免疫反应,所以用螯合剂(二乙烯三胺五乙酸,DTPA)将金属离子与载体蛋白(匙孔血蓝蛋白,KLH)连接起来。成功合成、鉴定汞复合物抗原后,免疫BALB/c小鼠,通过细胞融合获得了稳定分泌抗体的杂交瘤细胞。用极限稀释法亚克隆,通过ELISA筛选,获得了2株稳定分泌抗汞离子抗体的细胞株(H2H5,H1H8)。小鼠腹腔注射1×107H2H5、H1H8细胞株制备腹水,腹水抗体效价都在1∶51200以上。经鉴定两株杂交瘤均为IgG1亚类,轻链为kappa型且分泌抗体稳定性较好。实验结果为汞离子残留免疫学检测方法的建立提供了技术基础,对提高风险评估工作的效率和质量,保障食品安全有重要现实意义。     

农产品安全检测中生物传感器的应用

围绕农药和化肥残留、重金属污染、激素和兽药残留以及生物污染物等农产品安全性的主要指标．该对生物传感器在农产品安全检测领域中最新的发展动态进行了综述,并对其发展前景和存在问题进行了评述。     

Effect of the light chain C-terminal serine residue on disulfide bond susceptibility of human immunoglobulin G1λ

The light chain cysteine residue that forms an interchain disulfide bond with the cysteine residue in the heavy chain in IgG1κ is the last amino acid. The cysteine residue is followed by a serine residue in IgG1λ. Effect of the serine residue on the susceptibility of disulfide bonds to reduction was investigated in the current study using a method including reduction, differential alkylation using iodoacetic acid with either natural isotopes or enriched with carbon-13, and mass spectrometry analysis. This newly developed method allowed an accurate determination of the susceptibility of disulfide bonds in IgG antibodies. The effect of the serine residue on disulfide bond susceptibility was compared using three antibodies with differences only in the light chain last amino acid, which was either a serine residue, an alanine residue or deleted. The results demonstrated that the presence of the amino acid (serine or alanine) increased the susceptibility of the inter light and heavy chain disulfide bonds to reduction. On the other hand, susceptibility of the two inter heavy chain disulfide bonds and intrachain disulfide bonds was not changed significantly.     

Critical evaluation of municipal solid waste composting and potential compost markets

Mechanical biological treatment (MBT) of mixed waste streams is becoming increasingly popular as a method for treating municipal solid waste (MSW). Whilst this process can separate many recyclates from mixed waste, the resultant organic residue can contain high levels of heavy metals and physical and biological contaminants. This review assesses the potential end uses and sustainable markets for this organic residue. Critical evaluation reveals that the best option for using this organic resource is in land remediation and restoration schemes. For example, application of MSW-derived composts at acidic heavy metal contaminated sites has ameliorated soil pollution with minimal risk. We conclude that although MSW-derived composts are of low value, they still represent a valuable resource particularly for use in post-industrial environments. A holistic view should be taken when regulating the use of such composts, taking into account the specific situation of application and the environmental pitfalls of alternative disposal routes.     

Biosorption of heavy metals from aqueous solutions with tobacco dust

A typical lignocellulosic agricultural residue, namely tobacco dust, was investigated for its heavy metal binding efficiency. The tobacco dust exhibited a strong capacity for heavy metals, such as Pb(II), Cu(II), Cd(II), Zn(II) and Ni(II), with respective equilibrium loadings of 39.6, 36.0, 29.6, 25.1 and 24.5 mg of metal per g of sorbent. Moreover, the heavy metals loaded onto the biosorbent could be released easily with a dilute HCl solution. Zeta potential and surface acidity measurements showed that the tobacco dust was negatively charged over a wide pH range (pH > 2), with a strong surface acidity and a high OH⁻ adsorption capacity. Changes in the surface morphology of the tobacco dust as visualized by atomic force microscopy suggested that the sorption of heavy metal ions on the tobacco could be associated with changes in the surface properties of the dust particles. These surface changes appeared to have resulted from a loss of some of the structures on the surface of the particles, owing to leaching in the acid metal ion solution. However, Fourier transform infrared spectroscopy (FTIR) showed no substantial change in the chemical structure of the tobacco dust subjected to biosorption. The heavy metal uptake by the tobacco dust may be interpreted as metal–H ion exchange or metal ion surface complexation adsorption or both.     

Inhibitive determination of mercury and other metal ions by potentiometric urea biosensor

The biosensor with urease entrapped in PVC layer at the surface of pH-sensitive iridium oxide electrode was applied for testing of mercury and other metal ions inhibition on enzymatic reaction. The calculation of inhibition effect was based on the measurement of initial rate of decrease of biosensor potential (proportional to the initial rate of enzymatic reaction) after addition of substrate after inhibition step. Some differences of inhibition extent were observed for various mercury forms (Hg(NO3)2, HgCl2, PhHgCl and Hg2(NO3)2) as well as for other heavy metal ions investigated as potential interferents. Because the method was not specific, it was applied for the determination of total inhibition effect caused by heavy metal ions in water samples. In the case of most cations tested the total recovery of enzyme activity was possible using Tris buffer solution with EDTA and thioacetamide after less than 10 min regeneration time.     

人工饲养蕲蛇与野生蕲蛇中重金属元素及氨基酸含量的比较研究

目的:对人工饲养蕲蛇与野生蕲蛇中重金属元素及氨基酸含量进行测定和比较分析研究。方法:采用原子吸收法对蕲蛇中Cu、Hg、Cd、Pb、As含量进行测定;全自动氨基酸分析仪测定蕲蛇中氨基酸含量并进行相关性分析。结果:人工饲养蕲蛇与野生蕲蛇中重金属元素含量为均低于《中国药典》2010版限定值。人工饲养蕲蛇与野生蕲蛇中的氨基酸含量丰富,种类构成完整,均含有17种人体所需要的氨基酸,两者氨基酸含量的相关系数r=0.9991。结论:人工饲养蕲蛇与野生蕲蛇氨基酸含量和组成相似,两者存在线性正相关关系,且蕲蛇中重金属含量符合《中国药典》2010版标准,人工饲养蕲蛇可以作为野生蕲蛇的优良替代品。     

Iron, DtxR, and the regulation of diphtheria toxin expression

In recent years considerable advances have been made in the understanding of the molecular basis of iron-mediated regulation of diphtheria toxin expression. The tox gene has been shown to be regulated by the heavy metal ion-activated regulatory element DtxR. In the presence of divalent heavy metal ions, DtxR becomes activated and binds to a 9 bp interrupted palindromic sequence. The consensus-binding site has been determined by both the sequence analysis of DtxR-responsive operators cloned from genomic libraries of Corynebacterium diphtheriae as well as by in vitro genetic methods using cyclic amplification of selected targets (CAST-ing). it is now clear that DtxR functions as a global iron-sensitive regulatory element in the control of gene expression in C. diphtheriae. In addition, the metal ion-activation domain of DtxR is being characterized by both mutational analysis and determination of the X-ray structure at 3.0 Å resolution.     

Seasonal variability of detoxificant response and heavy metal accumulation in tissues of both sexes in <Emphasis Type="Italic">Tinca tinca</Emphasis> (L.) from Lake Trasimeno

Tinca tinca were sampled seasonally from Lake Trasimeno in order to investigate the influence of heavy metal accumulation and changing environmental parameters on the antioxidant responses in this species. Liver, gills and kidney of both sexes were analyzed for total glutathione, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, glyoxalase I, glyoxalase II, while muscle was analyzed for arsenic, lead, cadmium and mercury. The MRLs (maximum residue limits) set by actual regulation were not exceeded for heavy metals, but a seasonal and sex-linked variability of antioxidant parameters was observed, and major variations occurred especially in summer and autumn. In this shallow lake, heavy metal accumulation did not affect the biochemical variations, which are rather due to the decreased water level inducing hyperoxia and hypoxia within 24 h, high temperature and loss of mating and refuge areas.     

Health risk assessment of heavy metals via dietary intake of wheat in Golestan Province,Iran

Concentration of five heavy metals including lead (Pb), cadmium (Cd), copper (Cu), iron (Fe), and zinc (Zn) in wheat collected from silages of Golestan Province, Iran, was determined using atomic absorption spectroscopy. Dry ashing method was applied for precise determination of the five heavy metal contents. The concentrations of heavy metals were recorded as the following: Pb (0.013–0.14), Cd (0.008–0.031) by graphite furnace method and Cu (0.48–6.2), Fe (58.50–406.9), and Zn (3.41–32.75) by flame method, all in mg.kg^?1. The mean concentration of all the aforementioned heavy metals was (0.057 ± 0.003), (0.016 ± 0.005), (2.7 ± 0.17), (111.2 ± 21), and (5.7 ± 0.22) mg.kg^?1, respectively. The level of heavy metals decreased in the order of Fe>Zn>Cu>Pb > Cd. Highest amount was related to Fe and the lowest amount to Cd. Concentrations of heavy metals in all the wheat samples were below the permissible limits set by the Food and Agriculture Organization/World Health Organization and Iranian National Standard Organization and did not pose any threat to the health of consumers.     

Molecular Mechanisms and Genetic Basis of Heavy Metal Tolerance/Hyperaccumulation in Plants

Phytoremediation has gained increased attention as a cost-effective method for the remediation of heavy metal-contaminated sites. Because some plants possess a range of potential mechanisms that may be involved in the detoxification of heavy metals, they manage to survive under metal stresses. High tolerance to heavy metal toxicity could rely either on reduced uptake or increased plant internal sequestration,which is manifested by an interaction between a genotype and its environment. The growing application of molecular genetic technologies has led to increased understanding of mechanisms of heavy metal tolerance/accumulation in plants and, subsequently, many transgenic plants with increased heavy metal resistance,as well as increased uptake of heavy metals, have been developed for the purpose of phytoremediation. In the present review, our major objective is to concisely evaluate the progress made so far in understanding the molecular/cellular mechanisms and genetic basis that control the uptake and detoxification of metals by plants.