Identification and characterization of the chromium（Ⅵ） responding protein from a newly isolated Ochrobactrum anthropi CTS-325

A Gram-negative, chromium(VI) tolerant and reductive strain CTS-325, isolated from a Chinese chromate plant, was identified as Ochrobactrum anthropi based on its biochemical properties and 16S rDNA sequence analysis. It was able to tolerate up to 10 mmol/L Cr(VI) and completely reduce 1 mmol/L Cr(VI) to Cr(III) within 48 h. When the strain CTS-325 was induced with Cr(VI), a protein increased significantly in the whole cell proteins. Liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis revealed that this protein was a superoxide dismutase (SOD) homology. The measured superoxide dismutase activity was 2694 U/mg after three steps of purification. The SOD catalyzes the dismutation of the superoxide anion (O₂^·−) into hydrogen peroxide and molecular oxygen. This protein is considered to be one of the most important anti-oxidative enzymes for O. anthropi as it allows the bacterium to survive high oxygen stress environments, such as the environment produced during the reduction process of Cr(VI).     

沉积物中邻苯二甲酸二甲酯类的GC／MS测定

采用快速压力溶剂萃取仪（ASE）提取,弗罗里柱净化,气相色谱-质谱联用仪（GC／MS）对沉积物中邻苯二甲酸酯类化合物进行定性、定量分析。实验过程中采用铬酸洗液对实验器皿进行清洗,有效防止环境中邻苯二甲酸酯类物质对样品的污染。     

积极开发“城市矿山” 全面协调发展循环经济

从金属资源回收循环利用出发,把城市比喻成为一座储有优良矿产资源的＂城市矿山＂加以开发,寻求矿物资源,是经济社会可持续发展的必然选择。＂城市矿山＂比天然形成的真正矿山更具开发价值,关键是如何科学有序、有效地开发＂城市矿山＂,需要国家有关部门指导、规划和资金投入的支持。     

钠钙交换体对心肌保护作用的研究进展

心肌钠钙交换体是引起胞内钙超载的重要原因.简要综述了钠钙交换体的的结构特征、生理功能、病理作用以及在心肌保护方面的研究新进展.NCX反向转运的激活可能是心肌缺血预适应产生心脏保护作用的机制之一.     

火焰原子吸收法测定土壤中金属锌吸光度高的原因

通过实验发现,由于在消解过程中使用玻璃管移取氢氟酸,导致了玻璃中的锌进入了样品中,给样品的分析带来了干扰,从而导致了分析的失败.     

镉、铅在沉水植物龙须眼子菜叶片中的分布

采用室内浸提、扫描电镜附加能谱分析、差数离心和凝胶层析等手段,研究了镉、铅在龙须眼子菜(Potamogeton pectinatus)叶片中的分布.结果表明,龙须眼子菜对镉、铅具有很强的吸收能力,对溶液中镉、铅的平均去除效率分别为84%、91%.当镉、铅处理液浓度分别为6.67,83.00μmol/L时,龙须眼子菜对镉、铅的生物积累量分别为496,10800mg/kg,其中可溶态镉、铅的浓度分别为55.0,14.1mg/kg,说明龙须眼子菜叶片中的镉、铅大部分都是以结合态存在的.铅在龙须眼子菜叶细胞上的分布重量百分比及原子百分比均高于镉.15%的镉和25%的铅分布在龙须眼子菜的细胞壁中;56%的镉和25%的铅分布在液泡和胞基质中.龙须眼子菜叶片中除了有小分子蛋白与镉结合外,还有其他小分子有机物也能与镉结合,而铅则主要与小分子蛋白结合.     

纳米铁系材料与反硝化细菌复合去除地下水硝酸盐氮研究

采用不同液相还原法制备了纳米Fe、纳米Fe/Ni和油酸钠包覆型纳米Fe粒子,并将其与反硝化细菌复合应用于地下水中硝酸盐氮的去除研究中.分别考察了不同纳米铁系材料与反硝化细菌复合体系去除硝酸盐氮的反应速率及对脱氮产物生成的影响.同时,从核糖核酸(RNA)水平考察了不同纳米铁系材料对反硝化细菌的影响.结果表明,纳米Fe/Ni复合体系脱氮速率最快,6d内对硝酸盐氮的去除率可达到100%,最终产物主要为氨氮,占体系总氮的69%;而纳米Fe和油酸钠包覆型纳米Fe复合体系9d可将硝酸盐氮100%去除,氨氮的转化率分别为52%和16%.另外,从反应前后反硝化细菌总RNA浓度的变化情况看,纳米Fe/Ni复合体系、纳米Fe复合体系和油酸钠包覆型纳米Fe复合体系的反硝化细菌总RNA浓度分别降低了93%、40%和34%,可见3种纳米铁系材料对反硝化细菌毒性大小顺序为:纳米Fe/Ni纳米Fe油酸钠包覆型纳米Fe.     

一株Zn抗性菌株的筛选鉴定及吸附条件优化

采用浓度梯度法从铅锌尾矿区与污水灌溉区土壤中筛选了一株Zn抗性放线菌,并通过形态与培养特征、生理生化特性、细胞壁组分与16SrRNA基因序列分析对该菌株进行了鉴定.同时,综合运用单因素试验与正交试验法对该菌株吸附Zn2+的条件进行了优化.结果表明,菌株CCNWHX72-14经鉴定为高加索链霉菌(Streptomyces ciscaucasicus),其对Zn2+的抗性达到845mg·L-1.锌胁迫生长曲线表明,该菌株在130mg·L-1Zn2+胁迫时生长良好,且最适培养时间为7d.各个单因素条件对该菌株吸附Zn2+的影响顺序为:接种量初始Zn2+浓度初始pH转速温度.该菌株吸附Zn2+的最佳条件为:初始Zn2+浓度为150mg·L-1,初始pH=5,接种量为1%,转速为60r·min-1,温度为28℃.菌株CCNWHX72-14在最佳条件下对Zn2+的吸附较具有良好的重复性与稳定性,最高吸附量可达51.05mg·g-1,该研究为进一步探讨链霉菌的Zn2+吸附机制及其在生物修复中的应用奠定了基础.     

纳米催化剂Pd/SnO_2的制备及催化还原硝酸盐反应的调控

采用热分解法制备了SnO2载体,并用浸渍法制备了Pd/SnO2催化剂.同时,采用X射线衍射仪(XRD)、透射电镜(TEM)、扫描电镜(SEM)及BET比表面积仪等对所制载体和催化剂材料进行了分析表征.结果表明,热分解法和浸渍法都能够获得纳米材料,SnO2及Pd/SnO2的粒径均在9～10nm左右,比表面积分别达到144.99m·2g-1和147.36m·2g-1.在以甲酸为还原剂的Pd/SnO2催化还原硝酸盐体系中,在Pd与SnO2负载比为2%～7%,反应温度为20～50℃和甲酸投加量4.0～24.0mmol·L-1的条件下,催化活性为0.70～9.48mg·min-·1g-1,且催化活性随着负载比、温度和甲酸投加量的增大而增大,随着pH的升高先升后降,最佳pH为3.反应温度升高及pH降低都能够提高Pd/SnO2的选择性.甲酸-Pd/SnO2催化还原硝酸盐体系中还原反应的调控策略为:反应温度宜控制在40～50℃内,这样可同时获得较高的催化活性和选择性,温度过高对催化活性和选择性影响很小,温度过低则会同时降低催化活性和选择性;控制pH为3时,可以获得最大的催化活性及较好的选择性,pH升高会降低Pd/SnO2的催化活性和选择性,pH降低会导致催化活性迅速降低,但对选择性影响不大;甲酸与硝酸盐的物质的量比宜大于4:1,此时可以有效地抑制pH的上升,同时获得较高的催化活性和选择性,甲酸与硝酸盐的物质的量比小于4:1时,会同时降低Pd/SnO2的催化活性和选择性.     

Heavy metal （Pb,Zn） uptake and chemical changes in rhizosphere soils of four wetland plants with different radial oxygen loss

Lead and Zn uptake and chemical changes in rhizosphere soils of four emergent-rooted wetland plants; Aneilema bracteatum, Cyperus alternifolius, Ludwigia hyssopifolia and Veronica serpyllifolia were investigated by two experiments: (1) rhizobag filled with “clean” or metal-contaminated soil for analysis of Pb and Zn in plants and rhizosphere soils; and (2) applied deoxygenated solution for analyzing their rates of radial oxygen loss (ROL). The results showed that the wetland plants with di erent ROL rates had significant e ects on the mobility and chemical forms of Pb and Zn in rhizosphere under flooded conditions. These e ects were varied with di erent metal elements and metal concentrations in the soils. Lead mobility in rhizosphere of the four plants both in the “clean” and contaminated soils was decreased, while Zn mobility was increased in the rhizosphere of the “clean” soil, but decreased in the contaminated soil. Among the four plants, V. serpyllifolia, with the highest ROL, formed the highest degree of Fe plaque on the root surface, immobilized more Zn in Fe plaque, and has the highest e ects on the changes of Zn form (EXC-Zn) in rhizosphere under both “clean” and contaminated soil conditions. These results suggested that ROL of wetland plants could play an important role in Fe plaque formation and mobility and chemical changes of metals in rhizosphere soil under flood conditions.