肠道修复：一种利用益生菌减少重金属积累的新思路

近年来受到重金属工业废水的排放及人类日常活动的影响,我国大面积土壤中重金属含量急剧增高。不同重金属可能通过食物链进入人体,给人类健康带来隐患。因此,减少重金属在动物体肠道中的积累是降低重金属危害的一个重要课题。研究显示,一些益生菌能够在体内外环境中有效地结合重金属,但人们对益生菌结合重金属的能力,及其对重金属的肠道修复机理了解较少。本文针对目前镉、铅、铬等重金属对环境与动物体健康造成严重危害的现状,分析了各类重金属的污染来源,概括了益生菌在环境与动物体肠道中对各种重金属的修复情况及作用机理,重点考察了益生菌在动物体肠道环境中与重金属相互作用的机理研究,同时对未来利用益生菌制剂直接减少人体肠道内重金属积累进行了展望。     

Arsenic-induced toxicity and the ameliorative role of antioxidants and natural compounds

Arsenic (As) poisoning has proven to be a major threat worldwide because of its toxic effects on the human body. As toxicity through drinking water is a global health concern. The toxicity of As is known to affect the liver, kidney, lungs, muscles, cardiovascular system, and nervous system and can even induce diabetes. Further As can cause skin lesions leading to notable diseases in the skin like Bowen's disease. Chronic exposure to As has caused many tragedies in Eastern, and several Southeast Asian and Latin American countries. Long-term exposure to As makes it an immediate threat that should be dealt with as a priority, and one of the ways to handle it may be with the use of antioxidants. In this review, we have discussed the natural and anthropogenic sources of As, its metabolism, pathophysiology, and mechanism of toxicity. Besides, we have also discussed some of the synthetic chelators and the ameliorative role of antioxidants and natural compounds in reducing As toxicity.     

有机修复剂在重金属污染土壤修复中的应用

有机修复剂在重金属污染土壤修复中具有举足轻重的作用.本文结合国内外的研究成果和最新研究进展,从土壤重金属污染修复中有机修复剂应用的发展状况、应用机理、优缺点、影响因素以及成功实例等几个方面论述了国内外有机修复剂的研究现状,列举了几种应用较为广泛的有机修复剂(如氨基多羧基酸、有机酸、有机质、生物乳化剂等)的最新研究进展,总结了影响有机修复剂使用的主要因素,指出目前有机修复剂在实际应用中可能出现的问题,同时对今后的发展方向进行了展望.     

Incidence of heavy metals in the mangrove flora and sediments in Kerala, India

The mangroves of Kerala on the south-west coast of India are fast disappearing due to land reclamation and other anthropogenic disturbances. There are very few ecosystem level studies made in these much threatened biotopes in Kerala. The present study involves the measurement of heavy metals in the mangrove flora and sediments of three mangrove habitats along the Kerala coast. Sampling was carried out for a period of one year at bi-monthly intervals, with concentrations of Fe, Mn, Cu,Zn,Pb and Co analysed using atomic absorption spectrophotometry. An appreciable variation was observed in metal concentrations indifferent mangrove species. Cu, Zn and Pb were found to be in higher concentrations in Avicennia officinalis whereas higher levels of Fe, Mn and Co were observed in the species Barringtonia racemosa. The analysis of heavy metals indicated a high level of metal pollutants such as Fe, Cu, Zn and Pb in the mangrove habitats of Quilon and Veli compared to the relatively uncontaminated areas of Kumarakom. This revised version was published online in August 2006 with corrections to the Cover Date.     

Isolation and Characterization of Arsenic-Resistant Bacteria from Contaminated Water-Bodies in West Bengal,India

Bengal Basin is known for severe arsenic contamination. In the present study, we have isolated six bacteria from the arsenic contaminated surface water of Bengal Basin. 16S rDNA sequence analysis identified them as Microbacterium oleivorans, Acinetobacter soli, Acinetobacter venetianus, Acinetobacter junii, Acinetobacter baumannii, Acinetobacter calcoaceticus. All the isolates possess arsenic accumulation potential and high molecular weight plasmid (>10 kb). PCR amplification indicated the presence of arsenic-resistance genes (arsB and aoxB) either in the genome or plasmid or in both in the isolated bacteria (except in Acinetobacter venetianus). Exposure to arsenic affected bacterial growth and induced alteration in cytoplasmic membrane integrity.     

Physiological responses of plants to heavy metals and the quantification of tolerance and toxicity

Abstract

Techniques available for assessing the tolerance of plants to heavy metal toxins are reviewed. All are based on physiological responses and range from long-term growth trials in metal-contaminated substrates, to rapid cytological tests. Problems associated with the ecophysiological interpretation of in vitro measurements of tolerance are considered. The implications of multiple tolerance, co-tolerance, constitutional tolerance, inducible tolerance and possible stimulatory effects of metals on plant responses are discussed.     

乳酸菌对重金属吸附作用的研究进展

重金属污染是人们关注的食品安全问题热点之一,使用食品安全级乳酸菌吸附重金属成为了新的研究方向。本文在分析环境和食品中汞、镉、铅污染的来源及对人类危害的基础上,对微生物与重金属的相互作用进行介绍,重点归纳了乳酸菌作为重金属吸附剂的潜能,以及吸附重金属的作用机制和研究现状,为研发高效吸附重金属的乳酸菌吸附剂提供了可行性的思路。     

藻类富集重金属的特点及其应用展望

以藻类植物为主要对象的水体重金属修复已成为环境科学领域的研究热点.由于其特殊的细胞壁结构、较高的重金属富集能力、简便的解吸附方法等特点,藻类被认为是理想的生物吸附材料.文中简述了藻类适宜高富集重金属的结构及代谢特点,包括具有较高富集重金属能力的细胞壁功能基团、胞外产物、细胞内重金属螯合蛋白,以及生活藻类、死亡藻体及固定化处理后所表现出的高富集能力及简便的解吸附方法等,并对其用于污染水体修复的优缺点及应用趋势进行分析.     

Heavy metals toxicity in plants: An overview on the role of glutathione and phytochelatins in heavy metal stress tolerance of plants

Plants experience oxidative stress upon exposure to heavy metals that leads to cellular damage. In addition, plants accumulate metal ions that disturb cellular ionic homeostasis. To minimize the detrimental effects of heavy metal exposure and their accumulation, plants have evolved detoxification mechanisms. Such mechanisms are mainly based on chelation and subcellular compartmentalization. Chelation of heavy metals is a ubiquitous detoxification strategy described in wide variety of plants. A principal class of heavy metal chelator known in plants is phytochelatins (PCs), a family of Cys-rich peptides. PCs are synthesized non-translationally from reduced glutathione (GSH) in a transpeptidation reaction catalyzed by the enzyme phytochelatin synthase (PCS). Therefore, availability of glutathione is very essential for PCs synthesis in plants at least during their exposure to heavy metals. Here, I reviewed on effect of heavy metals exposure to plants and role of GSH and PCs in heavy metal stress tolerance. Further, genetic manipulations of GSH and PCs levels that help plants to ameliorate toxic effects of heavy metals have been presented.     

黄河水系沉积物重金属赋存形态及污染特征

2004年采集了黄河干流及西纳川等支流的水系沉积物,测定了沉积物样品中Cu、Zn、Pb、Cd、Cr、As和Hg等重金属元素的含量,并用BCR连续提取法分析研究了各元素的赋存形态,同时采用地累积指数法(Igeo)和次生相原生相分布比值法(RSP)分别对黄河流域水系沉积物中重金属的污染状况及生态风险进行了评估.结果表明:黄河水系沉积物中重金属含量特征总体符合全球页岩重金属元素丰度的基本趋势,但在部分人为污染较重的区域,表现出一定的地理差异;从浓度水平衡量,重金属的污染较轻;黄河水系沉积物中Cu、Zn、Cr和As主要以残渣态(B4)形式存在,具有较好的环境稳定性,而Pb、Hg和Cd以活性较大的弱吸附态存在,可能具有相对较大的环境影响;生态风险评价的结果显示,Pb、Cd和Hg具有相对较高的生态风险指数,尤其是Pb的潜在风险应该引起重视.     

重金属在土壤生态系统中的富集及毒性效应

对清水塘重金属污染区土壤生态系统重金属的富集及毒性效应的研究结果表明,土壤中 主要富集的重金属元素为生物毒性较强的Cd、Hg、As以及具有一定毒性的Zn、Pb、Cu,平均综 合污染指数为640.大型土壤动物重金属含量的分析结果表明,重金属富集量随污染程度的 增加而增加,尤其某些巨蚓科种类对Cd表现高富集,富集系数为1196.通过染毒试验进一 步证明,土壤动物种类和数量随Cd浓度的增加而减少.同工酶分析表明,Cd对蚯蚓同工酶活性 有明显的毒性效应.污染区主要种植蔬菜作物,而重金属在蔬菜体内的富集量也随污染 程度的增加而增加,其中蔬菜对Cd的富集有明显的品种间差异.     

Occurrence, use and potential toxic effects of metals and metal compounds

Metals and metal compounds are constituents of our natural environment. Their distribution depends on the existence of natural sources (e.g. volcanoes or erosion) and their use in human’s activity. They are transformed naturally (e.g. by bacterial activity) with formation of organic species that influence their mobility and accumulation in abiotic as well as biotic systems. Up to date metal species are released into the environment questioning their influence on human health. Due to their widespread use in human activities such as industry, agriculture and even as medicine (e.g. As, Se, Pt), numerous health risks may be associated with exposure to these substances. Different reports on metal intoxication are documented and studies especially on neurotoxicity, genotoxicity, or carcinogenicity, are previously published in numerous articles. This mini-review gives an overview on the use and the actions of selected metal species of actual scientific concern, with a focus on neuronal cells.     

重金属与农药污染的农业土壤脱毒过程研究进展

农业土壤环境自身脱毒过程是极其复杂的生态化学过程,对于土壤健康质量的维持和改善具有重要意义。然而,一直以来,人们对污染物的致毒过程研究得较多,对农业土壤自身脱毒能力及机制未给予足够重视。本文就农业土壤环境中,重金属与农药污染物的吸附脱毒、非生物降解(水解、光解)脱毒、微生物降解脱毒、土壤酶学脱毒、根际环境中的降解和转化脱毒以及植物富集固定进行了综述,并分析了各脱毒过程中所涉及到的反应机理。     

Health risk assessment of heavy metals in shellfish collected from Fujian,China

Abstract

With industrialization and human activities, shellfish may be contaminated by various pollutants such as heavy metals. This study aims at the concentrations of As, Cr, Mn, Ni, Cu, Zn, Cd, Sn, Sb and Pb in shellfish collected from Fujian of China, and the risk of heavy metals in shellfish on human health based on target hazard quotients (THQ). Results showed that the THQ values of the elements were far below 1, except for As with an average value of 1.148 in razor clam. No detrimental health effects of heavy metals on humans health was observed by daily consumption of mussel and oyster, but the exposed population to short-necked clam, scallop and razor clam might experience noncarcinogenic health risks because each of the total THQ values was above 1 for the three shellfish.     

重金属污染土壤修复技术研究的现状与展望

目前重金属污染土壤的修复主要采用物理化学技术和植物修复技术,根据其作用和过程和机物,物理化学技术主要包括化学固化,土壤淋洗和动电修复;植物修复技术包括植物稳定,植物挥发和植物提取,本文就各种修复技术的原理,优缺点,实用性及其国际研究与发展动态作一简述。     

Evaluation of some heavy metals toxicity in Channa punctatus and riverine water of Kosi in Rampur,Uttar Pradesh,India

This study was aimed to assess the bioaccumulation and concentration level of three heavy metals such as Chromium (Cr), Cadmium (Cd) and Lead (Pb) in the riverine water and edible fish, Channa punctatus obtained from River Kosi, Rampur, Uttar Pradesh, India. These toxic heavy metals are released into the environment because of E-waste, industrial activities, municipal urban runoff, coal burning, fertilizers etc., then paved the way into the aquatic system due to direct input, atmospheric deposition, and erosions caused by rain. There is every apprehension of aquatic animals getting exposed to elevated levels of heavy metals, thus possessing harmful effects both to flora and fauna. The concentrations of Cd, Cr and Pb in water were found to be 0.051 ± 0.026, 1.091 ± 0.408, and 0.019 ± 0.002 whereas in the kidneys of Channa punctatus, as 0.076 ± 0.208, 0.482 ± 0.059, and 0.127 ± 0.705 respectively.     

Relationship between the hemolytic action of heavy metals and lipid peroxidation

It is well known that some of the heavy metals have a hemolytic action, but the mechanisms responsible for this effect are not well established. In order to elucidate whether or not the hemolytic action of heavy metal ions is associated with the peroxidation of membrane lipids, the relationship between metal-induced hemolysis and the generation of malonaldehyde has been studied.The results obtained show that metal-induced hemolysis is associated with the development of peroxidative processes in erythrocyte membranes. The peroxidation is caused by metals with and without pro-oxidant catalytic action. The level of the malonaldehyde products rises before the appearance of hemolysis which proves that the development of peroxidative processes precedes but does not result from hemolysis.The suggestion has been made that the peroxidation of membrane lipids is a possible mechanism of damage to the red cell membrane in metal-induced hemolysis.     

Recent developments in the application of proteomics to the analysis of plant responses to heavy metals

Pollution of soils by heavy metals is an ever‐growing problem throughout the world, and is the result of human activities as well as geochemical weathering of rocks and other environmental causes such as volcanic eruptions, acid rain and continental dusts. Plants everywhere are continuously exposed to metal‐contaminated soils. The uptake of heavy metals not only constrains crop yields, but can also be a major hazard to the health of humans and to the entire ecosystem. Although analysis of gene expression at the mRNA level has enhanced our understanding of the response of plants to heavy metals, many questions regarding the functional translated portions of plant genomes under metal stress remain unanswered. Proteomics offers a new platform for studying complex biological functions involving large numbers and networks of proteins, and can serve as a key tool for revealing the molecular mechanisms that are involved in interactions between toxic metals and plant species. This review focuses on recent developments in the applications of proteomics to the analysis of the responses of plants to heavy metals; such studies provide a deeper understanding of protein responses and the interactions among the possible pathways that are involved in detoxification of toxic metals in plant cells. In addition, the challenges faced by proteomics in understanding the responses of plants to toxic metal are discussed, and some possible future strategies for meeting these challenges are proposed.     

迁安市农田重金属含量空间变异性

利用地统计学和GIS相结合的方法,对河北省迁安市农田土壤耕层（0～20 cm)8种重金属含量的空间变异性进行了研究.结果表明,农田中8种重金属含量均值未超过土壤环境质量(GB15618-1995)二级标准,属于中等变异.Cu、Zn、Ni、Cr和As含量的变异函数理论模型符合指数模型,空间相关程度强;Hg和Cd含量的变异函数理论模型符合球状模型,空间相关程度中等;Pb含量具有纯块金效应,空间相关程度弱.在整个研究尺度上,Pb含量具有恒定的变异,其余7种重金属含量由空间自相关部分引起的空间变异性起主要作用,空间相关距离为11～20 km.用普通Kriging方法对Cu、Zn、Ni、Cr、Hg、As和Cd含量空间局部插值表明,北部山地重金属含量较高,而中部盆地重金属含量较低.     

福建省耕地土壤重金属含量和可浸提性研究

测定了福建省6市、县耕地土壤中的Cu、Zn、Cd、Ni、Pb、Hg、As等7种重金属元素的全量和可浸提态含量,并对测定结果进行了数理统计。结果表明,福建省耕地土壤存在着不同程度的重金属污染,但依元素不同而不同,重金属可浸提态含量占全量的10.0?52.2 Cu、Zn、Cd、Pb、Ni的可浸提态含量与全量之间的相关达极显著水平,Zn、Cd、Pb、As等4元素含量之间存在着显著正相关,而Ni则只与Zn元素有极显著正相关,Cu和Hg与其它重金属元素的相关则均不显著。