铜污染土壤的生物修复研究进展

随着工业化与农业化进程的加快,土壤重金属污染问题日益突出。铜(Cu)既是生命体生长发育的必需微量元素,也是重金属污染物之一。土壤中过量的Cu不仅会对植物产生毒害,而且能够通过食物链的富集作用,对人类健康造成严重威胁。生物修复技术作为治理重金属污染土壤的一种新型技术受到广泛关注。文中对生物修复的主要技术如植物修复、微生物修复、植物-微生物联合修复、动物修复等在治理Cu污染土壤方面的研究进展进行综述,以期为重金属污染土壤有效治理和可持续农业的发展提供理论依据。     

微生物修复返溶铬污染场地的研究进展

目前,我国历史遗留铬渣堆场多数采用湿法解毒工艺进行处理,但大量化学药剂的添加不仅增加了成本,引入了污染物,而且随时间的延长铬渣中的Cr(Ⅵ) 源源不断的返溶,场地出现返黄现象,形成二次污染。为了持久稳定的修复铬渣,研究人员提出用微生物修复技术处理湿法解毒后铬渣中Cr(Ⅵ) 的返溶。文中综述了国内外微生物修复铬渣污染场地的研究进展,首先简述了铬渣的危害、处理现状及传统的铬污染修复技术,并以湿法解毒铬污染为例,重点揭示了处理后铬渣中Cr(Ⅵ) 的返溶机理,由此可知湿法解毒后的二次污染不可避免。随后详述了微生物修复Cr(Ⅵ) 过程中生物还原、生物吸附和生物矿化三大作用机理,并阐述了铬污染场地修复过程中微生物物种的响应及群落结构的演替,最后,总结了微生物修复铬渣的研究进展并展望了未来的研究方向。     

生物表面活性剂修复重金属污染研究进展

重金属在环境中积累会对动植物和人体健康造成危害。生物表面活性剂环境相容性好,在环境污染修复方面的应用日益受到关注。本文介绍了生物表面活性剂及其在重金属污染修复中的应用;生物表面活性剂与重金属络合的机理;影响二者络合的因素(如pH值、表面活性剂浓度、重金属存在形态等);对生物表面活性剂修复重金属污染的前景进行了展望。     

2020污染土壤的生物修复专刊序言

生物修复技术,作为可持续发展的重要方向,因其环境友好、高效且无二次污染并能从根本上解决土壤污染问题而受到关注,已经在土壤污染治理中得到了广泛的应用。为了梳理和凝练生物修复技术的发展状况,本专刊收录了该研究领域的16篇论文,分别从植物修复、微生物修复、联合修复、重金属吸收积累的相关分子机制、资源化再利用等方面,详细阐述生物修复技术的发展动态,展望未来的发展趋势,为促进生物修复技术的发展提供参考。     

植物耐盐的分子机理研究进展

综述了与植物耐盐性密切相关的小分子渗透物质（脯氨酸,甜菜碱,多元醇,多胺,果聚糖）,晚期胚胎发生富集蛋白（LEA）,调渗蛋白（OSM）,水通道蛋白,K^ 通道蛋白和ATPase等的合成及其相关基因的表达。     

石油污染土壤的生物修复技术

1　前　言在石油生产、贮运、炼制加工及使用过程中 ,由于事故 ,不正常操作及检修等原因 ,都会有石油烃类的溢出和排放。例如 ,油田开发过程中的井喷事故 ;输油管线和贮油罐的泄漏事故 ;油槽车和油轮的泄漏事故 ;油井清蜡和油田地面设备检修 ;炼油和石油化工生产装置检修等。石油烃类大量溢出 ,应当尽可能予以回收 ,但有的情况下回收很困难 ,即使尽力回收 ,仍会残留一部分 ,对环境 (土壤、地面和地下水 )造成污染。其进入土壤后 ,会破坏土壤结构 ,分散土粒 ,使土壤的透水性降低。其富含的反应基能与无机氮、磷结合并限制硝化作用和脱磷酸作…     

石油污染土壤的生物修复技术

简要综述了土壤生物修复技术及其在石油污染土壤修复中的应用现状,着重讨论了生物强化修复技术及其应用过程中所涉及的关键技术问题;介绍了真菌-细菌协同修复石油污染耕地以及该技术与秸秆填埋发酵相集成修复油-盐混合污染耕地的研究成果。     

土壤中抗生素的环境风险及污染土壤的生物修复技术

抗生素的广泛使用导致其在环境中普遍存在,所引发的抗性基因问题已对全球公共卫生构成重大威胁。土壤是环境中抗生素的重要汇,抗生素暴露会对土壤生物带来危害,甚至会间接对人体健康造成潜在风险,因此需采取有效手段修复抗生素污染的土壤。文中综述了抗生素对土壤植物表型生长指标、土壤动物生理特征及群落分布、微生物群落组成与功能的影响,以及抗生素抗性基因在土壤生物间的传播风险等;总结了利用耐受土壤植物、动物、微生物以及其互作关系修复抗生素污染土壤的潜力与前景,指出了已有土壤中抗生素环境风险和生物修复研究中尚存在的问题,展望了未来的研究方向。     

我国污染土壤生物修复技术的发展及现状

本文简要回顾了近30年来我国污染土壤生物修复技术的发展过程,主要包括生物修复技术在我国的发展阶段、生物修复的4大类型及其所适用对象与范围、生物修复用菌株的筛选与特性研究、活性菌株(菌剂)在典型污染土壤中的应用及其效果等,并针对土壤污染和生物修复技术的发展现状,简要讨论了未来生物修复技术的发展。     

铜污染旱地红壤的络合诱导植物修复作用

研究EDTA和低分子量有机酸对污染旱地红壤Cu形态变化及金属忍耐－富集型植物印度芥菜生长和Cu吸收的影响,以探讨Cu污染土壤的有机络合诱导植物吸取修复作用,结果表明,在芥菜营养生长旺盛期施用EDTA可显著提高土壤Cu的活性,土壤水浸提态Cu和交换态Cu均显著上升;这种活化效应随外加Cu浓度的上升和EDTA用量的增加而增大;柠檬酸和酸对土壤Cu的活化效应小,只对水浸提态Cu略有影响;EDTA可显著增加芥菜茎叶、根的Cu浓度和吸收量,等摩尔量柠檬酸和苹果酸对土壤铜形态变化和芥菜Cu吸收没有显著作用。     

酿酒酵母乙醇耐性的分子机制及基因工程改造

提高工业微生物对毒性代谢产物及高温等环境胁迫因素的耐受性对工业生产具有重要的意义。发酵过程中产生的乙醇对酵母细胞的生长和代谢都具有较强的抑制作用,是酿酒酵母的重要环境胁迫因素之一。对酿酒酵母乙醇耐性的分子机制的研究可为选育具有较强乙醇耐受性的酵母菌种提供理论基础。近年来,通过细胞全局基因转录分析和基因功能分析,对酿酒酵母乙醇耐性的分子机制有了更多新的认识,揭示了很多新的与乙醇耐性相关的基因,并在此基础上,通过对相关基因进行过量表达或敲除,成功提高了酵母菌的乙醇耐性。以下综述了近年来酵母菌乙醇耐性的生物化学与分子生物学机制的研究进展,以及构建具有较高乙醇耐性的酵母菌的基因工程操作。这些研究不仅加深了对酿酒酵母乙醇耐性的机理认识,也可为高效进行生物转化生产生物质能源奠定理论基础。     

Integrated tolerance mechanisms: constitutive and adaptive plant responses to elevated metal concentrations in the environment

Isolation and study of metal tolerant and hypersensitive strains of higher plant (and yeast) species has greatly increased our knowledge of the individual pathways that are involved in tolerance. Plants have both constitutive (present in most phenotypes) and adaptive (present only in tolerant phenotypes) mechanisms for coping with elevated metal concentrations. Where studies on the mechanisms of tolerance fall down is in their failure to integrate tolerance mechanisms within cell or whole-plant function by not relating adaptive mechanisms to constitutive mechanisms. This failure often distorts the relative importance of a proposed tolerance mechanism, and indeed has confused the search for adaptive mechanisms. The fundamental goal of both constitutive and adaptive mechanisms is to limit the perturbation of cell homeostasis after exposure to metals so that normal or near-normal physiological function may take place. Consideration of the response to metals at a cellular rather than a biochemical level will lead to a greater understanding of mechanisms to withstand elevated levels of metals in both contaminated and uncontaminated environments. Recent advances in the study of Al, As, Cd, and Cu tolerance and hypersensitivity are reported with respect to the cellular response to toxic metals. The role of genetics in unravelling tolerance mechanisms is also considered.     

种子顽拗性的形成机理及其保存技术

根据种子的脱水行为将种子分为正常性种子、顽拗性种子和中间性种子。顽拗性种子在发育的末期不经历成熟脱水．脱落时有相对高的含水量,并且对低温和脱水干燥非常敏感。在自然界,顽拗性种子存在一个连续群,即低度、中度和高度顽拗性种子,其差异在于对脱水伤害的敏感程度。影响种子顽拗性的因素,既有种子本身的生理生化物质基础,也有种子在母株上发育过程中所经受的外界环境的影响。目前,对种子脱水耐性的分子机制及其保存技术研究得较多。本文综述了有关顽拗性种子研究的近期进展。     

Molecular mechanisms of copper uptake and distribution

In the past few years, exciting advances have been made toward understanding how copper is transported into and distributed to cupro-proteins within cells. Recent work has identified high-affinity copper transporters at the plasma membrane in a number of organisms. The elucidation of the three-dimensional structure of copper chaperones and target cupro-proteins has shown that highly specific interactions between homologous domains foster copper transfer between conserved copper ligands, and facilitate a detailed understanding of vectorial copper-transfer reactions. Furthermore, the recent generation of mouse-knockout models, deficient in a high-affinity copper transporter, or in copper chaperones, has demonstrated the importance of copper uptake and targeted distribution in both predicted and fascinating unanticipated ways in growth and development.     

Elucidation of vancomycin's enantioselective binding site using its copper complex

Vancomycin forms a stable complex with Cu²⁻ in neutral aqueous solutions. The enantioselectivity of native vancomycin was compared to that of the copper-vancomycin complex using capillary electrophoresis (CE). There were significant differences in their enantioselectivities. This can be attributed to the fact that copper ion coordinates with some of the same functional groups in vancomycin that are essential for chiral recognition and enantioresolution. An amine moiety that provides one of the more important enantioselective interactions was identified. This chiral interaction site was illustrated using a color-coded, space-filling model of the X-ray crystal structure of the copper-vancomycin complex. Successful enantioselective interactions at lower pHs were attributed to the partial dissociation of the copper-vancomycin complex. Chirality 8:590–595, 1996. © 1997 Wiley-Liss, Inc.     

Molecular mechanisms of copper homeostasis.

Copper is an essential trace element which plays a pivotal role in cell physiology as it constitutes a core part of important cuproenzymes. Novel components of copper homeostasis in humans have been identified recently which have been characterised at the molecular level. These include copper-transporting P-type ATPases, Menkes and Wilson proteins, and copper chaperones. These findings have paved the way towards better understanding of the role of copper deficiency or copper toxicity in physiological and pathological conditions.     

Molecular mechanisms of plant metal tolerance and homeostasis

Transition metals such as copper are essential for many physiological processes yet can be toxic at elevated levels. Other metals (e.g. lead) are nonessential and potentially highly toxic. Plants – like all other organisms – possess homeostatic mechanisms to maintain the correct concentrations of essential metal ions in different cellular compartments and to minimize the damage from exposure to nonessential metal ions. A regulated network of metal transport, chelation, trafficking and sequestration activities functions to provide the uptake, distribution and detoxification of metal ions. Some of the components of this network have now been identified: a number of uptake transporters have been cloned as well as candidate transporters for the vacuolar sequestration of metals. Chelators and chaperones are known, and evidence for intracellular metal trafficking is emerging. This recent progress in the molecular understanding of plant metal homeostasis and tolerance is reviewed. Received: 14 July 2000 / Accepted: 22 September 2000     

Molecular dynamics characterisations of the Trp-cage folding mechanisms: in the absence and presence of water solvents

Protein folding is an important and yet challenging topic in current molecular biology. In this work, the folding dynamics and mechanisms of the Trp-cage mini-protein were studied with molecular dynamics simulations, in the absence and presence of water solvents. The important intermediates during the Trp-cage folding were determined by gradually decreasing the simulation temperature. The folding transition temperature was identified to be approximately 400 K, and the folding pathway was decomposed into six steps: U ? I ₁ ? I ₂ ? I ₃ ? I ₄ ? F ₁ ? F ₂, where U, I and F represent the unfolded, intermediate and folded states, respectively. The finding that the two helical subunits are successively formed is consistent with the experimental observations, and the Asp9/Arg16 salt bridge forms at the final stage and does not play a significant role during folding kinetics. The presence of water solvents induces hydrophobic collapse as the whole cage comparatively closes. Within aqueous solutions, the Trp-cage folding begins to contract into the meta-stable state, and by traversing the transition state it arrives at the native-like structure, which resembles the experimental structure closely.     

Stability of copper tolerance inThiobacillus ferrooxidans

A strain ofThiobacillus ferrooxidans MAL-4-1 was adapted to grow at higher concentrations of copper by repeated subculturing in the presence of increasing levels of added cupric ions in 9K medium. The strains adapted to copper were found to be more efficient in bioleaching of copper from concentrates. When copper tolerant strains were back cultured repeatedly in 9K medium without cupric ions, the initially developed metal tolerance was observed to be lost. This indicates that the copper tolerance developed is stress-dependent and not a permanent trait of the adapted strain.