首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
用PCR方法从嗜水气单胞菌DN322基因组中扩增出编码三苯基甲烷类染料脱色酶TpmD的基因,与表达载体pET-22b(+)连接构建成重组质粒pET22-tpmD,转化大肠杆菌BL21(DE3)得到重组工程菌株.结果表明,经IPTG诱导,脱色酶基因可高效表达,粗酶液降解结晶紫、孔雀石绿、碱性品红、灿烂绿的比活力达到569.5,386.9,516.1,273.0U/g.表达产物经Ni-NTA亲和层析法一步纯化,蛋白纯度达94.05%.对4种染料的比活力分别达到1075.3,1042.8,903.9,484.3U/g,重组质粒稳定存在于工程菌中,便于规模化发酵生产.  相似文献   

2.
《黑龙江环境通报》2008,28(1):76-76
The original article to which this Erratum refers was published in Prenatal Diagnosis 27; 2007, 882–883.  相似文献   

3.
4.
This paper reports on the major cations(Ca, Mg, Na and K) and arsenic(As) compositions of surface waters collected from major creeks, rivers and lakes in Central Victoria (Australia). The surface waters were found to be neutral to alkaline (pH 6.7-9.4), oxidised (average redox potential (Eh) about 130 mV) and showed variable concentrations of dissolved ions (EC, about 51-4386 /μS/cm). The concen- trations of dissolved major cations in surface waters were found to be in the order of Na〉〉Mg〉Ca〉K and in soils the contents of metals followed an order of abundance as: Ca〉Mg〉〉K〉Na. While Na was the least abundant in soils, it registered the highest dissolved cation in surface waters. Of the four major cations, the average concentration ofNa(98.7 mg/L) was attributed to the weathering of feldspars and atmospheric input. Relatively highly dissolved concentrations of Na and Mg compared with the world average values of rivers reflected the weathering of rock and soil minerals within the catchments. The As soil level is naturally high(linked to lithology) as reflected by high background soil values and mining operations are also considered to be a contributory factor. Under relatively alkaline-oxidative conditions low mobility of dissolved As (average about 7.9 μg/L) was observed in most of the surface waters with a few higher values(〉15 μg/L) around a sewage disposal site and mine railings. Arsenic in soils is slowly released into water under alkaline and/or lower Eh conditions. The efficient sink of Fe, AI and Mn oxides acts as a barrier against the As release under near neutral-oxidising conditions. High As content (average about 28.3 mg/kg) in soils was found to be associated with Fe-hydroxides as revealed by XRD and SEM analysis. The dissolved As concentration was found to be below the recommended maximum levels for recreational water in all surface waters(lakes and rivers) in the study area. Catchment lithology exerted the fundamental control on surface water chemistry. Sites impacted by mining waste dumps showed a decline in water quality.  相似文献   

5.
6.
Underground coal gasification (UCG) is an advancing technology that is receiving considerable global attention as an economic and environmentally friendly alternative for exploitation of coal deposits. UCG has the potential to decrease greenhouse gas emissions (GHG) during the development and utilization of coal resources. In this paper, the life cycle of UCG from in situ coal gasification to utilization for electricity generation is analyzed and compared with coal extraction through conventional coal mining and utilization in power plants. Four life cycle assessment models have been developed and analyzed to compare (greenhouse gas) GHG emissions of coal mining, coal gasification and power generation through conventional pulverized coal fired power plants (PCC), supercritical coal fired (SCPC) power plants, integrated gasification combined cycle plants for coal (Coal-IGCC), and combined cycle gas turbine plants for UCG (UCG-CCGT). The analysis shows that UCG is comparable to these latest technologies and in fact, the GHG emissions from UCG are about 28 % less than the conventional PCC plant. When combined with the economic superiority, UCG has a clear advantage over competing technologies. The comparison also shows that there is considerable reduction in the GHG emissions with the development of technology and improvements in generation efficiencies.  相似文献   

7.
新时期中外高校体育教育思想发展趋势比较分析   总被引:3,自引:0,他引:3  
本文介绍了德国和俄罗斯学校在体育发展的多方向、多功能的趋势,分析了我国高校体育教育的现状,从体育与健康课程整合的方面,提出高校体育应借鉴国外体育教育强国的思想观念,强调体育教改应重视学生身心的全面成长,贯穿“个体化、专项化、社会化”的思想。  相似文献   

8.
本文介绍了德国和俄罗斯学校在体育发展的多方向、多功能的趋势,分析了我国高校体育教育的现状,从体育与健康课程整合的方面,提出高校体育应借鉴国外体育教育强国的思想观念,强调体育教改应重视学生身心的全面成长,贯穿“个体化、专项化、社会化”的思想。  相似文献   

9.
磺酰脲类除草剂DPX—E9636的水解机理   总被引:4,自引:0,他引:4       下载免费PDF全文
邵颖  王琪全 《环境科学》1997,18(2):9-11
对室温下DPX-E9636的水解产物分离纯化后,运用元素分析,紫外光谱及^1H核磁共振鉴定了主要产物的结构。产物为:1-(4,6-二甲氧基嘧啶基-2)-3(乙磺酰基-2-吡啶基)脲、N-(4,6-二甲氧基嘧啶基-2)-3-乙磺酰基-2-胺基吡啶、3-乙磺酰基-2-胺基吡啶及2-胺基-4,6-二甲氧基嘧啶,由此推测了DPX-E9636的水解机理。  相似文献   

10.
超声协同紫外灭活大肠杆菌实验研究   总被引:1,自引:0,他引:1  
应用紫外、超声、超声协同紫外对大肠杆菌进行灭活,并从生物学角度对协同机理进行探讨。结果表明:实验条件下,紫外辐照剂量与大肠杆菌灭活率之间具有良好的线性关系,各紫外辐照剂量下的E.coli均发生了光复活现象。超声功率密度对于灭活结果具有显著意义(p0.05),研究中超声灭活大肠杆菌的最大相对功效值对应的工况为7.18W/cm2作用80s。超声的协同作用使紫外线消毒动力学方程K值由0.1增至0.1358,减小了细菌对UV的抗性;与单独紫外作用比较,超声与紫外协同作用的光复活率有所降低。超声与紫外同时作用对细胞形态结构产生严重的破坏,超声作用只能改变细胞的结构,而不能破坏其DNA;利用T4-EndoⅤ对CPDs的特异性识别特性,可发现经各工况处理后,大肠杆菌DNA均被降解,产生大量CPDS,且各工况下ESS含量变化曲线与各工况下大肠杆菌灭活率曲线的相关系数达到0.92。  相似文献   

11.
12.
13.
采用生物学技术对高效降解线性微囊藻毒素-LR(microcystin-LR,MC-LR)的USTB-05-B酶进行克隆表达及纯化研究。首先利用分子克隆技术得到重组菌pET30a(+)/USTB-05-B/BL21(DE3)。在诱导剂IPTG浓度为0.25 mmol/L、温度30℃和诱导时间4 h条件下,重组菌能大量表达目的蛋白。然后利用亲和层析柱对重组菌破碎后的无细胞提取液(cell free extracts,CE)进行纯化,当咪唑浓度为100 mmol/L时,洗脱下来的蛋白纯度高。最终得到USTB-05-B蛋白纯度为91.1%,浓度为0.205 mg/m L。纯化后的USTB-05-B酶具有较高的活性,能在1 h内将10.8 mg/L的线性MC-LR降解完全。纯化后的目的蛋白为研究USTB-05降解MCs分子机理奠定基础,为有效提高降解MCs速率提供新材料。  相似文献   

14.
15.
本文报道了近年来检测水质中总大肠菌群及埃希氏大肠杆菌的方法学研究进展。按其作用原理可概括为3类。第1类是通过对培养基成份及培养条件的改进达到检测目的;第2类是用酶底物0NP G和MUG与细菌产生的半乳糖苷酶及葡萄糖苷酸酶起反应,根据色泽及荧光的显示以证实总大肠菌群及埃希氏大肠杆菌的存在;第3类是采用“聚合酶链反应——基因探针”方法,根据DNA分子杂交试验以检测水样中的总大肠菌群及埃希氏大肠杆菌。其中,酶学方法较敏感,色泽及荧光显示明确,操作方便,能较快获得结果,比其他2类方法具有较多优点。  相似文献   

16.
17.
This paper is a contribution to the debate on the redefinition of needs and perspectives of university level education in the field of sustainable design. It discusses the role of design research in relation to the production of new educational forms, methods and tools for a new generation of designers (and designer educators) enabling them to more effectively confront the transition towards a sustainable society. The paper is based on two premises; Firstly: in today’s climate there is a need for a general redefinition of education, as a result of the influence of new technological opportunities and changed socio-cultural conditions. Secondly: the design activity itself needs to be redefined in order to positively and effectively contribute to the radical change required by the transition towards a sustainable society. Industrial designer, educators and other design practitioners are all searching for ways to enhance their environmental capabilities and to produce sustainable designs. The academic discipline of design education in Italy (at the higher educational level) has responded by broadening its scope to produce more ‘environmentally skilled’ designers sensitive to issues of sustainable production and consumption. The Interdepartmental Research Centre in Innovation for Environmental Sustainability (CIR.IS) of the Politecnico di Milano University has developed an innovative and highly flexible response to these new design education needs. A set of interrelated projects—co-ordinated by the author—is outlined in the following paragraphs. These projects are funded by the Italian Environmental Protection Agency (ANPA). A university network (RAPI.RETE) has been established and a group of innovative and technologically advanced tools (ECO.CATHEDRA, ECO.OFFICINA, ECO.DISCO and DPS.MANUAL) are being developed to support teachers and students in the educational content and processes. The tools are now going to be distributed (free of charge) in Italian Universities and, both the ANPA and the CIR.IS have given their consent for their translation/adaptation into other languages (without charge).  相似文献   

18.
北京城市塑料垃圾年产量的模拟预测及其影响因素分析   总被引:1,自引:0,他引:1  
揭示城市塑料垃圾年产量及影响因素、预测其发展趋势对于城市生活垃圾收集系统的优化、处理技术的合理选择和降低环境影响具有重要意义.本研究基于1989年以来北京塑料垃圾占比、城市生活垃圾产量数据和社会经济数据,利用赤池信息量准则(AIC)和灰关联度法研究了北京城市塑料垃圾占比的年变化趋势和城市塑料垃圾年产量的主要影响因素.通过多元线性回归模型(MLR)、灰色系统模型GM(1,1)和BP神经网络模型对北京城市塑料垃圾年产量进行了模拟预测.结果表明,北京城市塑料垃圾占比由1989年的1.88%,增加到2012年的14.87%.基于AIC准则预测2013—2050年北京城市塑料垃圾占比增长趋势较平缓、稳定在14%~19%之间.2000—2012年北京市城市塑料垃圾年产量由40.2×104 t增加到121.1×104 t,年增长15.5%.人均可支配收入是影响北京城市塑料垃圾年产量的最大社会经济因素,而常住人口的影响较低.BP神经网络是模拟预测北京城市塑料垃圾产量的最佳模型,其模拟预测结果表明:2013年后北京市塑料垃圾年产量随时间呈不规则的非线性增长趋势,到2025、2035、2050年北京城市塑料垃圾产量将分别达到335、488和859×104 t,将对北京城市生活垃圾处理处置与防控管理带来巨大挑战.  相似文献   

19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号