Linearity assumption in soil-to-plant transfer factors of natural uranium and radium in Helianthus annuus L

The linearity assumption of the validation of soil-to-plant transfer factors of natural uranium and (226)Ra was tested using Helianthus annuus L. (sunflower) grown in a hydroponic medium. Transfer of natural uranium and (226)Ra was tested in both the aerial fraction of plants and in the overall seedlings (roots and shoots). The results show that the linearity assumption can be considered valid in the hydroponic growth of sunflowers for the radionuclides studied. The ability of sunflowers to translocate uranium and (226)Ra was also investigated, as well as the feasibility of using sunflower plants to remove uranium and radium from contaminated water, and by extension, their potential for phytoextraction. In this sense, the removal percentages obtained for natural uranium and (226)Ra were 24% and 42%, respectively. Practically all the uranium is accumulated in the roots. However, 86% of the (226)Ra activity concentration in roots was translocated to the aerial part.     

Elimination of natural uranium and (226)Ra from contaminated waters by rhizofiltration using Helianthus annuus L

The elimination of natural uranium and (226)Ra from contaminated waters by rhizofiltration was tested using Helianthus annuus L. (sunflower) seedlings growing in a hydroponic medium. Different experiments were designed to determine the optimum age of the seedlings for the remediation process, and also to study the principal way in which the radionuclides are removed from the solution by the sunflower roots. In every trial a precipitate appeared which contained a major fraction of the natural uranium and (226)Ra. The results indicated that the seedlings themselves induced the formation of this precipitate. When four-week-old seedlings were exposed to contaminated water, a period of only 2 days was sufficient to remove the natural uranium and (226)Ra from the solution: about 50% of the natural uranium and 70% of the (226)Ra were fixed in the roots, and essentially the rest was found in the precipitate, with only very small percentages fixed in the shoots and left in solution.     

Toxic effects of Cu on growth, nutrition, root morphology, and distribution of Cu in roots of Sabi grass

Sabi grass (Urochloa mosambicensis (Hack.) Dandy) (a C4 species of Poaceae) is commonly used to revegetate disturbed sites in low-rainfall environments, but comparatively little is known regarding copper (Cu) toxicity in this species. A dilute nutrient solution culture experiment was conducted for 10 d to examine the effects of elevated Cu²⁺ activities ({Cu²⁺}) on the growth of Sabi grass. Growth was inhibited by high Cu in solution, with a 50% reduction in the relative fresh mass occurring at 1.0 μM {Cu²⁺} for the roots and 1.2 μM {Cu²⁺} for the shoots. In solutions containing 1.2-1.9 μM {Cu²⁺}, many of the roots ruptured due to the tearing and separation of the rhizodermis and outer cortex from the underlying tissues. Transmission electron microscopy revealed that Cu-rich deposits were found to accumulate predominantly within vacuoles. Due to limited translocation of Cu from the roots to the shoots, phytotoxicity is likely to be more of a problem in remediation of Cu-toxic sites than is Cu toxicity of fauna consuming the above-ground biomass.     

向日葵ACC氧化酶基因(HaACO1)的克隆及表达分析

目的:克隆向日葵中的ACC氧化酶基因(HaACO1),并对其进行生物信息学分析及盐胁迫表达分析,为理解向日葵ACC氧化酶生理功能并加强对ACO基因的利用奠定基础。方法:以前期从盐胁迫的内葵杂4号根中获得的ACC氧化酶基因片段4-4-7TDF(KM823963)为基础,通过RT-PCR和5'/3'RACE技术克隆ACO基因的全长cDNA序列,利用生物信息学软件对获得的cDNA序列及编码的蛋白质序列进行分析。同时采用PCR方法克隆基因组DNA(genemic DNA,gDNA)序列,并对其进行结构分析。利用实时荧光定量PCR分析Na Cl胁迫下向日葵根、下胚轴、叶中HaACO1的表达量和不同NaCl浓度及不同胁迫时间下根中Ha ACO1的表达量。结果:Ha ACO1的cDNA序列全长为1 135bp,其开放阅读框为942bp,编码313个氨基酸。预测其分子质量和等电点分别为35.84k Da和5.13,基因登录号为KP966508。HaACO1与已报道的多种植物的ACO基因核苷酸序列及其推导的氨基酸序列有较高的相似性,分别为76%~83%和77%~88%。gDNA起始密码子至终止密码子序列长1 018bp,包含2个外显子和1个内含子,基因登录号为KP988289。实时荧光定量PCR分析表明向日葵HaACO1在不同器官及不同NaCl浓度、不同时间诱导下存在特异性表达差异。结论:获得的向日葵HaACO1是植物ACO家族成员之一,该基因应答盐胁迫具有独特的表达模式。     

Ni2+、Cu2+、Cd2+对2-氯酚厌氧降解影响的研究

以2-氯酚（2-CP）为目标污染物，研究了厌氧颗粒污泥对不同初始浓度的2-氯酚的降解性能以及镍、铜、镉三种重金属离子对2-CP厌氧降解的影响。试验结果表明，驯化后的厌氧颗粒污泥对2-CP具有良好的降解效果；不同的重金属离子对2-CP厌氧降解的影响存在差异，但就总体而言，除低浓度的镍离子对2-CP的厌氧降解具有轻微促进作用外，Ni^2＋、Cu^2＋、Cd^2＋对2-CP的降解均存在抑制作用。采用降解速率比评价了三种重金属离子对厌氧体系的毒性，其大小顺序为：Cu^2＋〉Ni^2＋〉Cd^2＋。此外，还引入分配系数描述了厌氧颗粒污泥对重金属离子的截留情况，发现其对三种重金属离子的截留能力为：Cu^2＋〉Cd^2≈Ni^2＋，截留率均在58％以上。     

活性污泥系统中Cu~(2+)、Zn~(2+)竞争吸附规律研究进展

从处理含重金属离子的城市污水的现状出发,简述了在不同p H值、温度、时间、活性污泥等条件下重金属离子的吸附规律,综述了目前国内外有关活性污泥系统中,重金属离子竞争吸附规律的最新研究成果,并对其吸附原理进行了解析。     

Batch Pb2+ and Cu2+ removal by electric furnace slag

An evaluation of the application of electric furnace slag (EFS) as an adsorbent to remove Pb2+ and Cu2+ from industrial effluents is presented. The paper examines phase composition of EFS by using X-ray diffraction of powder. In the batch experiments, parameters studied include the effect of initial concentration of lead and copper ions, temperature, and contact time. Over the temperature range studied (293-313 K) the results of adsorption experiments could be fitted by using both Langmuir and Freundlich models and thermodynamic values of deltaG0, deltaH0 and deltaS0 corresponding to each adsorption process were calculated. Satisfactory conformity between experimental data and the model-predicted values was expressed by the correlation coefficient (R2). Both Langmuir and Freundlich models described the Pb2+ and Cu2+ sorption processes adequately, with correlation coefficient (R2) values ranging from 0.9760 to 0.9994. Data from this study indicated the potential use of the tested electric furnace slag, a by-product from "Felis" foundry in Sisak, Croatia, as Pb2+ and Cu2+ sorbents from the industrial effluents.     

3种重金属联合对孔雀鱼肝脏抗氧化酶系统的影响

以孔雀鱼为受试生物,研究了3种重金属(Cu2+、Cd2+和Cr6+)联合毒性对孔雀鱼肝脏抗氧化酶系统的影响。结果表明:重金属对孔雀鱼肝脏3种抗氧化酶均有不同的影响,其中孔雀鱼肝脏CAT、GSH-PX活性在暴露2天后均被显著诱导,随着时间的延长酶活性逐渐降低,暴露8天后活性低于对照组。孔雀鱼肝脏SOD活性在暴露2天后呈现诱导效应,随着浓度的增大,诱导效应明显。在高浓度暴露条件下,暴露2天后SOD活性显著升高,但随着暴露时间的延长,SOD活性降低。     

Role of cell surface components on Cu2+ adsorption by Pseudomonas putida 5-x isolated from electroplating effluent

A gram-negative bacterium Pseudomonas putida 5-x with high Cu2+ accumulating capability was isolated from electroplating effluent in Kwun Tong, Hong Kong. The pretreated cells without superficial layer-capsule, isolated cell envelopes and the separated peptidoglycan layer materials were obtained from fresh P. putida 5-x cells, their Cu2+ adsorption capacities and properties were compared with that of the fresh cells. Pretreatment by 0.1 mol L(-1) HCl enhanced Cu2+ adsorption capacity due to the degradation of cell superficial layer-capsule of P. putida 5-x cells. Isolated cell envelopes possessed five times more Cu2+ adsorption capacity than that of fresh intact cell. The Cu2+ adsorption of separated peptidoglycan layer materials indicated that the peptidoglycan layer only played 10-15% part of the Cu2+ adsorption capacity, and implied other cell surface components such as outer membrane or inner membrane might play an important role in such high Cu2+ binding of the cell envelopes. The adsorption process of fresh cells, pretreated cells and cell envelopes of P. putida 5-x could be described with Freundlich isotherm, while the adsorption of Cu2+ by separated peptidoglycan layer materials was better described with Langmuir isotherm.     

EPR examination of Zn2+ and Cu2+ binding by pigmented soil fungi Cladosporium cladosporioides

The purpose of this study was to examine the usefulness of electron paramagnetic resonance spectroscopy (EPR) to estimate zinc and copper ions biosorption from the environment by pigmented soil fungi Cladosporium cladosporioides. The existence of a low amount of pheomelanin, besides eumelanin, in C. cladosporioides samples was proved by the analysis of shape of their EPR spectra. Concentration of o-semiquinone free radicals in crude mycelium was 2.4x10(17) spin/g. Changes in free radicals system of C. cladosporioides cultured in the presence of Zn2+ and Cu2+ were analysed. Both magnetic and chemical interactions of zinc and copper ions with free radicals in C. cladosporioides melanin were found. Magnetically interacting diamagnetic Zn2+ ions increased the concentration of o-semiquinone free radicals in melanin existing in C. cladosporioides mycelium, whereas paramagnetic Cu2+ ions decreased this concentration. Chemical interactions of Zn2+ and Cu2+ ions decreased the free radical concentrations in C. cladosporioides melanin. Homogeneously distributed free radicals in C. cladosporioides melanin rise its activity in biosorption processes.     

专创融合视角下行业高职院校创新创业教育发展路径探究

专业教育与创新创业教育相融合是当前高校开展创新创业教育的方向。在专创融合视角下，提出构建“价值引领—资源配置—生态建设”的职业院校创新创业教育顶层设计，依据共生理论完善生态建设的路径选择问题：培育学校、企业、行业、创业者（学生）四位一体的共生环境，融入共生理念，振作共生精神；寻求内创业、互通资源、联合共建等共生行为模式创新；搭建以粤港澳铁路青年创新创业联盟为基础的共生界面。     

微量Cu2+对过氧化氢异丙苯热稳定性的影响

为研究微量铜离子（Cu2+）对过氧化氢异丙苯（CHP）热分解的影响,采用绝热加速量热仪（ARC）对CHP及含两种不同浓度Cu2+的CHP进行了绝热分解测试,研究了不同浓度Cu2+对CHP起始的分解温度（To）、最高分解温度（Tf）、绝热温升（△Tad）、最大温升速率（mm）等热力学参数及分解活化能（Ea）的影响,并利用热惰性因子（Φ）对实验数据进行了修正。结果表明：微量Cu2+的加入对CHP分解的热力学参数有影响,而且浓度不同影响不同。如CHP的校正起始分解温度（To,s）和Ea分别为111.28 ℃和170.93 kJ/mol,而加入（1.85×10-3）%或（3.70×10-3）% Cu2+后,相应的参数分别为104.26 ℃、164.73 kJ/mol和98.87 ℃、145.63 kJ/mol。表明微量Cu2+的存在能降低CHP的起始分解温度To,s和活化能Ea,且浓度越高,降低越明显,从而增加了CHP的热分解风险。     

Equilibrium and kinetic ion exchange studies of Pb2+, Cr3+, Fe3+ and Cu2+ on natural clinoptilolite

In the present study ion exchange of Pb2+, Cu2+, Fe3+ and Cr3+ on natural clinoptilolite is examined at 27 +/- 1 degree C and initial concentration of 10 meq/dm3. Equilibrium is favorable for Pb2+, unfavorable for Cu2+ and sigmoid for Cr3+ and Fe3+. Selectivity series deduced from equilibrium isotherms is Pb2+ > Cr3+ > Fe3+ > Cu2+, while when maximum exchange levels (MELs) are considered, selectivity series is Pb2+ > Cr3+ approximately = Cu2+ > or = Fe3+. Cu2+ manifests the higher value of diffusion coefficient in the clinoptilolite particles among the metals studied, equal to 1.40 x 10(-9) cm2/s. According to the fixed bed experiments the upflow rate (5-15 Bed Volumes (BV)) is influencing the breakthrough point for all metals studied. The breakthrough point varies between 12.3 BV for Pb2+ and 1.18 for Cu2+. Flow rate is also influencing the operating capacity, giving values between 0.433 meq/g(clinoptilolite) for Pb2+ and 0.053 for Fe3+. Breakthrough point values confirm the selectivity order deduced from the equilibrium isotherms, while operating capacity values confirm the selectivity order deduced from MEL experiments.     

SO42-、COD、Fe2+、Cu2+及其交互作用对消化气中H2S含量的影响

采用正交试验的方法,探讨了影响消化气中H2S含量的主要因素．通过极差分析和方差分析确定c（SO4^2-）=5mmol／L,COD=4000mgO2／L,c（Fe^2＋）=20mg／L,c（Cu^2＋）=20mg／L时,消化气中H2S含量最小为13．1μg／L．     

电凝聚法去除废水中重金属离子Cr6+、Cu2+的研究

考察了初始pH值、电解时间、电流强度、NaCl投量、离子共存及曝气量等因素对电凝聚法处理含Cr6+、Cu2+废水的影响。结果表明,随初始pH值的升高,对Cr6+的去除率呈先上升后下降的趋势,并在pH值=6时达到最高,而对Cu2+的去除率逐渐上升,并在pH值=5时达到最高后趋于稳定;对Cr6+、Cu2+的去除率均随反应时间及电流强度的增大而增大,并在时间为20min、电流强度为4 A时达到了比较稳定的去除效果;NaCl投量对Cr6+、Cu2+的去除率基本没有影响,其作用是适当地提高废水的电导率,降低能耗;对混合溶液中Cr6+、Cu2+的去除效果比单一溶液时好,金属离子共存对电凝聚处理重金属废水起促进作用;适当的曝气会提高重金属的去除率。     

光电催化技术同时降解有机物与回收重金属的研究

采用光电组合法同时实现了罗丹明B的氧化降解和Cu2+的回收.TiO2/Ti薄膜电极作为光电催化阳极,光电催化产生的氧化剂可有效氧化罗丹明B;不锈钢作为光电催化反应阴极,游离的Cu2+在阴极得到电子被还原沉积回收.针对5 mg/L罗丹明B和0.2 rnmol/L Cu2+的混合体系,光电催化氧化技术、光催化氧化与电化学氧化过程对罗丹明B的去除率分别为80％、50％、40％,对Cu2+的回收率分别为78％、8％、60％,可见光电组合具有良好的协同作用.光电组合处理罗丹明B和Cu2+的最佳pH值为3.5、电流密度应控制在0.3～ 0.6 mA/cm2.研究结果显示光电催化技术可作为罗丹明B和Cu2+混合废水的一种处理方法.     

Cd2+胁迫对短程反硝化的影响与微生物群落变化

接种城市污水厂二沉池污泥,以乙酸钠为碳源,通过合理控制NO₃^--N浓度和COD/NO₃^--N启动短程反硝化(PD),并考察了长期投加不同Cd²⁺浓度的PD性能、胞外聚合物EPS和微生物群落变化。经过84 d的驯化成功启动PD,出水NO₂^--N浓度和亚硝酸盐积累率(NAR)均处于较高水平,其最高值分别为33.94 mg/L和81.24%,系统平均NAR为71.99%。Cd²⁺胁迫试验表明,与空白对照组S1相比,S2(2.5 mg/L)、S3(5 mg/L)和S4(10 mg/L)均呈现不同程度的短程反硝化性能恶化趋势,到第36天S2、S3和S4平均NAR分别下降了12.48%、14.59%和19.00%,但在高浓度Cd²⁺(5、10 mg/L)条件下,系统仍具有较高的NAR。重金属对微生物活性的毒性抑制导致S2的EPS含量高于S3和S4的EPS含量,EPS含量显著增加说明微生物通过分泌大量EPS来吸附Cd²⁺。微生物高通量测序表明,变形菌门、拟杆菌门和绿弯菌门居PD系统主导地位,反应器NO2^--N积累菌属Thauera的丰度表现为S2(2.13%)>S3(0.28%)>S1(0.2%)>S4(0.1%),表明10 mg/L的Cd²⁺不利于Thauera菌属生长,Cd²⁺浓度低于5 mg/L时Thauera菌属有生长的趋势。     

Effects of lead toxicity on the total chlorophyll content and growth changes of the aquatic plant Ceratophyllum demersum L.

This paper reports results of a laboratory-scale experiment conducted to determine the effects of different initial concentrations of a toxic heavy trace metal (lead) on the total chlorophyll (a + b) content of aquatic plant tissues Ceratophyllum demersum L., and also to monitor the visible growth changes during the experiment under different lead concentrations (2, 4 and 6 mg/L), as well as in control plants (without any addition of lead nitrate solution). Lead concentrations in water and plant samples were determined using AAS, where the total chlorophyll content in plant leaf tissues was measured every 15 days during the experimental period using a UV/VIS Spectrophotometer, Model 160A, Shimadzu, with wavelengths of 665 and 649 nm. The results showed that the content of total chlorophyll decreased noticeably, with increasing initial concentrations of lead throughout the exposure time. Decreases in total chlorophyll content in the tissues of C. demersum over the period of the experiment were accompanied by different morphological changes in the plants, depending on the initial lead concentration and exposure duration. These changes in morphology and growth affected the number and length of branches, the number of leaves and the number of leaflets.     

几种物理因素对黄芩细胞悬浮系生长与黄芩苷含量变化的影响

为建立稳定的黄芩细胞悬浮系,采用悬浮细胞培养技术,研究了接种量、光照与否和pH值等3种物理因素对黄芩细胞悬浮系生长与黄芩苷含量变化的影响。结果表明,黄芩细胞悬浮系浊度随培养时间呈现"S"形变化曲线;采用MS基本培养基,添加0.2 mg·L-1 2,4-D、2.0 mg·L-1 6-BA和3%蔗糖,选取1.0 g·L-1的接种量、pH 5.8,并在25℃条件下进行暗培养,最有利于黄芩苷的积累,黄芩苷含量最高可达7.425μg·g-1FW。