应用于PCR-DGGE分析的活性污泥微生物总DNA提取方法比较

探讨适用于PCR-DGGE分析研究的活性污泥细菌和真菌的DNA提取方法。采用5种方法提取活性污泥微生物基因组DNA,以DNA纯度、含量、片段大小及DGGE条带多样性作为考察指标评价提取方法的优劣,以确定最佳实验方案。紫外吸收法和琼脂糖凝胶电泳结果显示,试剂盒法提取的DNA含量最低,其余4种方法获得的DNA含量无显著差异,就DNA纯度而言,试剂盒法最优;除高温裂解法对真菌细胞壁裂解效果较差外,其他4种方法均能不同程度地裂解细菌和真菌细胞;DGGE结果表明,高温裂解法获得的细菌条带最多,基于SDS的细胞裂解法得到的真菌条带最多。综合分析,高温裂解法更适合于活性污泥中细菌的PCR-DGGE分析,基于SDS的细胞裂解法则更适合于污泥中真菌的PCR-DGGE分析。     

废水处理系统中活性污泥总DNA的提取

对废水脱氮除磷厌氧-缺氧-好氧系统中的活性污泥样品经过或未经预处理,比较了超声波法、玻璃珠震荡法和冻融法3种细胞裂解方法对DNA提取效果的影响。吸光度和琼脂糖凝胶电泳检测结果表明:活性污泥经TENP和PBS预处理后采用冻融法加2%SDS裂解细胞的DNA提取操作,可以得到数量多、纯度高的活性污泥DNA样品,可不经纯化直接进行PCR扩增反应。     

环境DNA在监测表层沉积物中的运用及其与环境变量的关系

环境DNA技术是近几年出现的新兴环境生态监测技术,为研究环境变量对表层沉积物中环境DNA变化的影响,通过小试实验模拟海水环境并以日本大螯蜚作为目标生物,引入4组不同的生物丰度,运用环境DNA技术研究了表层沉积物中环境DNA含量变化与周边环境变量的关系。在小试装置中养殖日本大螯蜚4 d后全部取出,之后启动实验。在实验启动后的第0、6、12、18、24、72、144、264、384小时进行取样,提取出的环境DNA片段含量通过实时荧光进行定量PCR检测。结果表明,表层沉积物中的环境DNA在源生物移除后72 h内降低至较低含量水平,与水体中的环境DNA有较为相似的变化特征。通过广义线性回归分析,发现环境DNA降解速率与水质盐度呈显著负相关(P=0.000 5),与pH呈显著正相关(P=0.04),说明表层沉积物中的环境DNA对于周边环境变化具有一定指示意义。上述结果为进一步推动环境DNA技术的应用及其对环境变量影响作用的深入研究提供参考。     

重金属污染河流生态修复区沉积物砷形态分析

生态修复是重金属污染河流治理的重要手段之一,以云南省文山州内跨境河流小白河生态修复区为研究对象,探析了不同形态砷在小白河生态修复区沉积物表层(0~10cm)、中层(10~20cm)和底层(20~30cm)的空间分布规律。结果表明:(1)表、中、底层中主要以残余态砷存在;残余态砷随沉积物深度的增加占比逐渐增大。表层中可氧化态砷弱酸可提取态砷可还原态砷;中层中可氧化态砷弱酸可提取态砷可还原态砷;底层中可氧化态砷可还原态砷弱酸可提取态砷。(2)小白河表层沉积物中砷全量总体呈B断面D断面C断面。(3)有机质与可还原态、可氧化态砷的结合趋势较大。(4)随着采样深度的增加,可提取态砷明显减少。故在利用该生态修复区进行环境治理时,应该重点针对表层沉积物进行定期清淤,减少该层沉积物的环境风险。     

活性污泥总DNA提取方法的比较

从处理某制药废水的MBR反应器中采集活性污泥，评价不同DNA提取方法对其总DNA提取效率的影响。DNA提取分细胞裂解和DNA纯化2步，对细胞裂解比较了珠磨匀浆法、反复冻融法、十二烷基磺酸钠（sodium dodecyl sulfate，SDS）裂解法等7种方法；对DNA纯化比较了酚/氯仿纯化法和胶回收纯化法。结果表明,SDS裂解法、酚氯仿纯化法最优。通过条件优化实验，确定SDS裂解酚/氯仿纯化法在污泥量1.1 g，10 000 r/min离心5 min的操作条件下，获得的DNA产量（10 774 μg/g泥重）和纯度（OD₂₆₀∶OD₂₈₀=1.84）等综合指标最好。     

一种活性污泥总DNA提取方法的优化

对3种活性污泥DNA提取方法———传统蛋白酶K-SDS-氯仿异戊醇法(CPSCI法)、液氮研磨法和脱腐处理法进行了对比,并针对CPSCI法从污泥量、保温时间、裂解方式及沉淀时间等4个方面进行了优化。结果表明,优化的蛋白酶K-氯仿-异戊醇法(OPSCI法)采用污泥量0.10 g、37℃静置10 min,加SDS常温旋涡振荡及异丙醇直接离心等条件可获得长度在23.1 kb左右的DNA,OD260nm/OD280nm为1.86,稀释10倍后即可进行16S rDNA PCR。该方法重复性好,提取得率高,纯度好,操作简便,为常规实验室开展活性污泥微生物多样性研究提供了帮助。     

多环芳烃在淮河、黄河和卫河沉积物上的吸附及解吸行为研究

以淮河沉积物上多环芳烃的吸附研究为主线,以黄河、卫河沉积物为比对,研究菲和芘在3种河流沉积物上的吸附和解吸行为,重点考察吸附剂有机质组分、环境温度、吸附时间和共存物等因素对吸附的影响,找出可以用来预测这3条河流沉积物对多环芳烃吸附作用的模式。结果表明,菲和芘在3种河流沉积物上的吸附均呈非线性,可用Freundlich方程拟合,属放热反应、物理吸附。同一吸附质的有机碳归一化分配系数(Koc)数值相近,说明吸附剂有机质组分对吸附起主导作用;吸附能力随着吸附时间延长而增加,并与吸附质疏水性成正比;多环芳烃共存,有竞争吸附现象;辛醇/水分配系数可用来预测3种河流沉积物对多环芳烃的吸附作用;解吸存在滞后现象,吸附质疏水性强、吸附剂有机质含量高的体系,解吸滞后现象更加明显。     

巢湖入湖河流沉积物中有机磷的形态分级研究

为识别巢湖流域污染物的特征、来源及其沉积物有机磷各形态分布与富营养化的关系，测定了7条巢湖入湖河流沉积物中有机磷各形态的含量，分析不同污染类型人湖河流沉积物中有机磷各形态分布的差异及与其他因素间的相关性。研究发现，不同污染类型人湖河流沉积物中水土保持控制型河流沉积物中有机磷各组分的相对含量顺序为残渣态Po〉富里酸-Po〉HCl-Po〉胡敏酸-Po〉NaHCO3-Po，平均的相对比例为7．5：3．1：1．9：1．5：1．0，而城市污染控制型和面源污染控制型河流沉积物中有机磷各组分的相对含量顺序恰好相同，面源污染控制型河流沉积物Po各形态含量低于城市污染控制型和水土保持控制型河流。中活性P。和OM、TP、Pi、Po、TN、NaHCO3-Pi、NaOH—Pi呈正相关，非活性Po与Po、NaOH-Pi呈显著正相关关系，反映了中活性Po很容易转化为生物可利用磷和非活性Po，且非活性Po仍然具有潜在的生物活性。     

第二松花江沉积物中汞的形态分布

河流水体中的汞,大部分积累在沉积物中。而汞含量高的沉积物,也向水和大气中释放汞。沉积物是汞迁移转化过程的一个重要环节。沉积物中汞的形态分布,决定着沉积汞的稳定性,同时对汞的迁移转化、河流对汞的自净能力,也有着十分重要的影响。化学浸提法,历来是汞形态研究的主要方法之一。近年来,国内一些单位对各种浸提法进行了研究和评价。在前人工作的基础     

环境样品中DNA提取方法的研究进展

利用微生物降解污染物是废水处理中的常用方法,研究废水处理工艺中微生物的多样性和动态性对于优化废水处理工艺的性能、提高其处理效率具有重要的指导意义.分子生物学方法是研究微生物多样性和动态性的有效方法.由于大多数分子生物学方法都是以提取研究对象的基因组DNA为前提,因此建立一种高效的环境样品DNA的提取方法具有重要作用.综述了从环境样品中提取DNA的主要方法及其研究进展,并提出了一种有效的从活性污泥中提取DNA的具体方法.     

Optimization of Height of Release of Air Pollutants

A number of key projects in the Environmental Protection Agency (EPA) particulate R&;D program having applicability to industry are presented. For electrostatic precipitators (ESP) there is presented the result of work on large diameter discharge electrodes which provide a decrease in penetration of up to a factor of 4 when compared to conventional small diameter electrodes. Also discussed is the multistage ESP which provides a collection efficiency that would require a collecting plate area 4 or 5 times larger with conventional ESP technology. The E-SOX technology makes use of the multistage concept to free up space in the ESP for SO₂ removals of up to 90%. Electrostatically augmented fabric filtration provides a reduction in pressure drop of about 5 0% as compared to conventional fabric filtration. Wind tunnel modeling of windbreaks for material storage piles indicates a potential for providing engineering design data that would allow significant emission reduction caused by wind erosion     

Investigation of the characteristics of the reflectivity of clouds

This paper investigates some of the reflectivity characteristics that clouds (when modelled as solid bodies) must exhibit to be compatible with observations that the reflecting surface of a cloud (i) appears almost equally bright across its face, (ii) is brightest when the cloud is opposite to the Sun but decreases in brightness as the cloud moves to other positions and (iii) increases in brightness with increasing optical thickness of the cloud in the observer's line of sight. These observations, respectively, are shown to imply that the peak value of the bidirectional total reflectivity from a cloud surface (i) increases in inverse proportion to the cosine of the angle between the Sun and the normal to the cloud surface, as the incident angle increases, (ii) appears to be directed back in the direction of the incident radiation, and (iii) increases as optical thickness of the cloud in the observer's line of sight increases. The results could have application in many fields (e.g. modelling diffuse radiance distributions for cloudy skies).     

Estimation of uncertainty of sampling for analysis of pesticide residues

Abstract

A computer model was used to take random samples from primary sample populations obtained from field trials to simulate the uncertainty of sampling for residue analysis of plant commodities and soil. The results indicate about 40%, 30% and 20% relative uncertainty when random samples of size 5, 10 and 25 are taken respectively, from a single lot. Therefore the sample size should be the same for establishing and enforcing legal limits.     

扬中生态环境建设的思考与实践

结合扬中生态环境的基本情况和存在的不足，进行了具体分析，对扬中未来生态建设的发展方向提出了建议及实施措施。     

实验室质量管理体系内部审核的实施

在实施ISO／IEC17025：1999标准《检测和校准实验室能力的通用要求》过程中，通过实验室质量管理体系内部审核的实践与系统分析，识别出内部审核实施阶段的关键环节，提出召开首次会议、收集审核证据、确定审核发现和召开末次会议的技术方法，对提高内部审核的质量和有效性、获得可靠的审核结论具有重要意义。     

次氯酸钠发生器的研制

介绍了电解法生产次氯酸钠的原理 ,并在原有生产工艺的基础上进行了重新设计和对设备的重新选择、改造 ,得出了各个工艺参数的最佳值 ,生产出高品质的次氯酸钠     

An application of the theory of kinematics of mixing to the study of tropospheric dispersion

The most common technique used for numerical simulations of tracer mixing is that of the numerical solution of the advection–diffusion equation with the unresolved fluxes parameterized using the similarity theory. Despite correct predictions of the overall directions of transport, models based on a numerical solution of the advection–diffusion equation lack sufficient accuracy to correctly reproduce the coupling of mixing with small scale processes which are sensitive to the microstructure of the tracer distribution. The objective of this paper is to revisit the basic formalism employed in numerical models used to investigate atmospheric tracers. The main mathematical method proposed here is the theory of kinematics of mixing which could be applied effectively for simulations of atmospheric transport processes. At the beginning of the paper, we introduce simple mathematical transformations in order to demonstrate how complex topological structures are created by mixing processes. These idealistic flow systems are essential to explain transport properties of much more complex three-dimensional geophysical flows. An example of the application of the kinematics of mixing to the analysis of tracer transport on a planetary scale is presented in the following sections. The complex filamentary structures simulated in the numerical experiment are evaluated using some commonly applied statistical measures in order to compare the results with the data published in the literature. The results of the experiment are also analysed with the help of simple conceptual models of fluid filaments. The microstructure of the tracer distribution introduced in the paper is essential to increase our understanding of atmospheric transport and to develop more realistic parameterizations of small-scale mixing. The presented results could also be used to improve calculations of the coupling between microphysical processes and tracer mixing.     

Comparison of methods for evaluation of activity of photocatalytic films

Objective

This work aims to investigate the correlation between the photocatalytic activity determined by methylene blue bleaching (DIN 52980), stearic acid degradation, and degradation of acetone in gas phase.

Method

The photocatalytic TiO₂ coatings included in this investigation ranged from thin commercially available coatings (Activ^TM and BioClean^TM) and ready to use suspensions (Nano-X PK1245) to lab-produced PVD and sol?Cgel coatings. XRD analysis of the photocatalytic coatings showed that all the coatings consisted of nanocrystalline anatase, although the thickness and porosity varied considerably.

Results

The study showed that the reproducibility of the activity measurements was good. However, more importantly, the investigation showed that there is a good correlation between the activities determined by the different methods even though the characteristics of the photocatalytic coatings and the organic probe molecules varied considerably.

Conclusion

The overall findings of this work suggest that there is a good correlation between the investigated methods. These results are promising for the future work concerning standardization of methods for determination of the activity of photocatalytic films.     

Impact of overexploitation of shellfish: northeastern coast of India

India has a very extensive coastline of about 7515 km, rich in diverse living resources. These resources continue to deteriorate with rampant harvesting or are altered for other uses such as aquaculture and fisheries. The present paper deals with degrading coastal habitats in northeastern India, and projects the intensity of the stress arising from the collection of tiger prawn seeds (Penaeus monodon) for aquacultural farms and molluskan shells for poultry feed and edible lime. Indiscriminate exploitation of these resources leads to a heavy reduction of the species concerned and other associated marine communities. The magnitude of such destruction has been quantified. The impacts of biodiversity loss and their after-effects on the ecobalance of this coastal system have become a matter of great concern to ecologists to maintain security and sustainability. The authors propose a public awareness program on themes relating to the importance of biodiversity for human livelihoods.