一种高效提取焦化废水活性污泥总DNA的方法

对焦化废水活性污泥中微生物建立高质量的总DNA提取方法是开展分子生态学研究的重要前提.通过反复冻融-蛋白酶K-SDS、溶菌酶-反复冻融-SDS及溶菌酶-反复冻融-蛋白酶K-SDS这3种综合方法对焦化废水活性污泥总DNA进行提取,以OD260/OD280、OD260/OD230、产率、片段完整性、片段大小5个指标来评价样品总DNA的提取效果.结果表明,溶菌酶-反复冻融-蛋白酶K-SDS法所提取的总DNA的OD260/OD280值约为1.8,产率为1.90～16.30 μg·g-1,片断完整性好,主带清晰,大小约为23 kb,其PCR反应抑制物少,能够直接进行16S rRNA基因的PCR扩增.溶菌酶-反复冻融-蛋白酶K-SDS法能够为焦化废水活性污泥中微生物的分子生态学研究提供高质量的总DNA.     

不同浓度甲醛致大鼠肝细胞DNA氧化损伤作用

为了探讨外源性化合物暴露致内脏细胞DNA氧化损伤程度的定量检测方法,尝试以8\|羟基脱氧鸟苷（8-hydroxy-2′-deoxyguanosine, 8-OHdG）为分子生物标志物,以甲醛为模式外源性化合物,以丙二醛（malondialdehyde, MDA）为参考指标,应用大鼠肝细胞悬液进行体外染毒实验研究.同时,实验设置甲醛染毒的终浓度分别为0、5、15、45μmol· L-1,在大鼠肝细胞悬液染毒1h后,分别测量了肝细胞悬液中的8-羟基脱氧鸟苷（8-OHdG）和丙二醛（MDA）含量.研究结果显示,随着甲醛浓度升高,大鼠肝细胞中8-OHdG和MDA含量均呈升高趋势（F=59.55,p<0.01;F=75.82,p<0.01）,高浓度组（45μmol·L-1）8-OHdG和MDA含量与对照组的差异均具有显著性（p<0.01）,中浓度组（15μmol·L-1）的这种差别也具有显著性（p<0.05, p<0.01）,低浓度组（5μmol·L-1）的这种差异没有显著性（p>0.05）.因此,8-OHdG不但可以用于血液和尿液样品的检测,而且采用本项研究摸索出的前处理方法可以很好地定量测定内脏细胞DNA氧化损伤的程度.     

pH值对SBR生物反应器出水溶解态有机质含量与构成的影响

为探讨污水二级生化出水中有机物(EfOM)的构成特点和变化规律,采用配置生活污水,对不同pH值运行条件下, SBR生物反应器出水中的溶解态有机质(DOM)含量和构成进行了比较研究.结果表明,运行期间pH值的调节对SBR反应器出水DOM含量与构成的影响均较大.初始pH为6.5的SBR反应器, pH值降低为6.0后,出水DOC由原来的4.0mg·L-1不断升高,进一步提高pH值,能够起到一定的缓解作用;初始pH为8.0的SBR反应器,出水DOC从4.0mg·L-1快速降低并保持在2mg·L-1左右, pH值降低为6.5后, DOC变化不大.单宁酸和蛋白质、碳水化合物、DNA等微生物代谢产物(SMPs)是出水DOM的主要组成部分, pH值对SMPs生成的影响是一个长期的过程,运行过程中降低pH值,造成出水SMPs含量不断升高. pH值对整个循环过程中溶解态有机物降解情况的影响,在厌氧阶段发挥了主要作用,较高pH值有利于厌氧阶段有机物的降解,而好氧阶段的有机物降解受pH值影响不大.     

镉致仔猪睾丸支持细胞抗氧化酶活性降低及DNA损伤研究

为了研究镉对仔猪睾丸支持细胞毒性影响,以仔猪睾丸支持细胞为实验模型,采用二步酶消化法分离支持细胞进行培养,并通过油红O和免疫细胞化学方法进行鉴定,探讨了0、10、20、40、80μmo.lL-1氯化镉对支持细胞的毒性作用.结果表明,二步酶消化法能分离出纯度较高的支持细胞,10μmol·L-1以上的氯化镉对支持细胞的生长具有抑制作用,并能使支持细胞的丙二醛含量升高,超氧化物岐化酶、谷胱甘肽过氧化物酶活性下降,造成支持细胞DNA损伤,并随着氯化镉浓度的增大存在明显的剂量-效应关系.     

Effects of plant species coexistence on soil enzyme activities and soil microbial community structure under Cd and Pb combined pollution

The relationship between plant species coexistence and soil microbial communities under heavy metal pollution has attracted much attention in ecology. However, whether plant species coexistence could o set the impacts of heavy metal combined pollution on soil microbial community structure and soil enzymes activities is not well studied. The modified ecological dose model and PCR-RAPD method were used to assess the e ects of two plant species coexistence on soil microbial community and enzymes activities subjected to Cd and Pb combined stress. The results indicated that monoculture and mixed culture would increased microbe populations under Cd and Pb combined stress, and the order of sensitivity of microbial community responding to heavy metal stress was: actinomycetes > bacteria > fungi. The respirations were significantly higher in planted soil than that in unplanted soil. The plant species coexistence could enhance soil enzyme activities under Cd and Pb combined. Furthermore, planted soil would be helpful to enhance soil genetic polymorphisms, but Cd and Pb pollution would cause a decrease on soil genetic polymorphisms. Mixed culture would increase the ecological dose 50% (ED50) values, and the ED50 values for soil enzyme activities decreased with increasing culture time. The dehydrogenase was most sensitive to metal addition and easily loses activity under low dose of heavy metal. However, it was di cult to fully inhibit the phoshpatase activity, and urease responded similarly with phosphatase.     

环境基因组技术在微生物多样性研究中的应用

环境中的微生物具有极大的生物多样性,但99%的微生物不能通过标准的实验技术加以培养,不依赖于培养的环境基因组技术由于适合分析生态系统中整个复杂的微生物基因组而迅速发展起来。文章针对环境基因组技术的原理、方法以及目前该技术在环境微生物多样性研究中的应用等作一综述。     

Interaction of DNA with aromatic hydrocarbons fraction in atmospheric particulates of Xigu District of Lanzhou, China

Voluminously epidemiological studies show that the relationships exist between the air pollution and human health and cancer. Aromatic hydrocarbons(AHs)in air form a large class of organic pollutants,which are widely in environment and many of them are known to be carcinogenic and/or mutagenic and contribute to ambient air pollution.In the past decades,bioassays mainly have been used to evaluate the toxicity of chemical mixtures in atmospheric particulates or aqueous environment.However,it is well known that the covalent complexes formed by carcinogens with DNA may be exert negative results in bioassay.So the main aim of this paper is to develop an evaluation method of toxicity effects of chemical mixtures in atmospheric particulates from chemical standpoint.In this study,the in vitro interaction of the AHs with DNA was investigated by absorption,fluorescence and resonance light scattering (RLS)spectroscopic techniques.The results showed that the AHs in the atmospheric particulates could combine with calf thymus DNA(ctDNA)and herring sperm DNA(hsDNA)without being activated or metabolized by organism,respectively.Intercalation may be present in the mechanism of interaction.The binding constants of the AHs with ctDNA and hsDNA were 2.5×10~2 and 2.0×10~3, respectively,which indicated that the interaction of the AHs with hsDNA is stronger than that with ctDNA.In addition,the relationships of dose-effect between the total mole concentration of chemical components and the ability of binding ctDNA and hsDNA were confirmed.This research made it possible to study the toxicity effects of chemical mixtures in atmospheric particulates by chemical method.It is believed that the composition and contents of unknown AHs and the interaction of DNA with AHs in atmospheric particulates of Xigu District of Lanzhou City,China are first reported in the past twenty years.     

四溴联苯醚(BDE-47)对菲律宾蛤仔组织解毒代谢酶活力与DNA损伤的影响

研究了四溴联苯醚(BDE-47)对菲律宾蛤仔(Ruditapes philippinarum)鳃丝和消化盲囊芳烃羟化酶(AHH)、谷胱甘肽硫转移酶(GST)、超氧化物歧化酶(SOD)活力和还原型谷胱甘肽(GSH)含量、DNA损伤(F值)的影响.结果表明:BDE-47对菲律宾蛤仔鳃丝和消化盲囊AHH、GST、SOD活力和...     

镉暴露致黑斑蛙精巢氧化损伤与DNA损伤

在实验条件下,将健康性成熟黑斑蛙(Rana nigromaculata)暴露于0.005、0.01、0.05、0.1、0.5和1.0 mg·L-1浓度的镉溶液中30 d,采用慧星实验检测其精巢细胞DNA损伤,并测定精巢组织中活性氧自由基(ROS)的水平和脂质过氧化主要终产物丙二醛(MDA)含量,探讨镉暴露对黑斑蛙精巢组...     

Electromagnetic irradiation exposure and its bioindication – An overview

Man made electromagnetic irradiation and fields cover now the globe due to the recent extensive propagation of mobile telephony. The increased load affects animals and also plants. Especially birds have been studied. Humans are also sensitive. They are good bioindicators as epidemiological methods are available. Humans can also report symptoms which cannot be directly measured with presently available technologies. The nonionizing irradiation can as the ionizing one break the DNA, damage proteins, even increase the blood brain barrier permeability, disturb the night rest, cause fatigue and hormonal disturbances. An increase of the tumours of human head has been described in correlation with the long term mobile phone use and on that side more exposed. The regulations covering mobile telephony are already about two decades old and need re-evaluation. The multitude of irradiation and the interaction of the different wavelength exposures, i.e., frequency sensitivity is poorly known at present. We should not forget the comparative studies of different species especially those which rely in their lives on electromagnetic orientation physiology. Some countries have issued warnings on the exposures of children. The producers of mobile technology have recently warned the users not to keep those devices in active stage in skin contact.