〔3H〕PBNA与小牛胸腺DNA的结合

经多种动物实验证明,工业用抗氧化剂N-苯基-2-萘胺(PBNA)为一种广谱的弱致癌物,本实验用管内研究方法证明了其在有微粒体活化系统存在时与小牛胸腺DNA的结合,这种结合有剂量—反应关系,并随温育时间而上升,约4h趋于平稳,用Sephadex G-15柱层析得到三个与λ_(260)相对应的同位素结合峰,表明这种结合在性质上是小牛胸腺DNA同PBNA代谢物的共价结合。     

溴氰菊酯对大鼠肝微粒体酶的影响

本实验研究了溴氰菊酯对雄性大鼠肝微粒体苯胺羟化酶活力和细胞色素P-450含量的影响。结果发现溴氰菊酯在动物体内能降低苯胺羟化酶活力(23.80％)和细胞色素P-450含量(21.18％)。该效应与微粒体脂质过氧化反应无关,亦与肝细胞破坏或内质网膜通透性的改变无关。溴氰菊酯本身对肝微粒体酶并不呈现抑制作用,当用肝微粒体酶诱导剂苯巴比妥诱导肝微粒体酶后,溴氰菊酯降低微粒体酶活性的效应消失。这表明溴氰菊酯降低肝微粒体酶的作用可能与其干扰肝微粒体酶蛋白的合成有关。     

2-硝基芴在大鼠肝匀浆S-9组分作用下的还原代谢

初步研究了在氮气保护无氧条件下,经Aroclor1254诱导的大鼠肝微粒体酶对2-硝基芴的还原代谢过程.对代谢体系及条件进行了选择用HPLC对代谢产物进行分离研究,经保留时间及紫外光谱核对显示2-硝基芴的主要还原代谢产物为2-氨基芴,除此之外还有三个量少的其代谢产物形成,因含量低而尚未进行结构鉴定.     

致癌物对草鱼原代肝细胞培养物中DNA修复的诱导作用

用直接致癌物N-甲基亚硝基胍或需经酶活化才有活性的致癌原苯并(a)芘、苯并(a)蒽处理草鱼原代肝细胞培养物后,用放射自显影方法测出有明显的DNA修复合成。对照有标记~3H-胸腺嘧啶核苷的细胞非常少,证明草鱼原代肝细胞中DNA复制水平很低。 ~3H-胸腺嘧啶核苷掺入鱼原代肝细胞DNA的量与各种致癌物及致癌原的浓度有关。这表明鱼肝细胞有能力将致癌原代谢成能损伤DNA的致癌物,从而刺激DNA的修复。 BHC(六六六)可以诱导草鱼原代肝细胞培养物的DNA修复,但氯化镉没有活性。 本报告表明致癌物可诱导鱼肝细胞的DNA修复,因此它可以作为生物监测环境致癌物的补充手段。     

2－硝基芴大鼠肝微粒体体外代谢研究

初步研究了在通风条件下，经Ａｒｏｃｌｏｒ１２５４诱导的大鼠肝微粒体酶对２－硝基芴的体外代谢。通过液相色谱、气相色谱、质谱、紫外光谱及红外光谱，首次分离和检测出单羟芴和二羟基芴等代谢产物，但未测得明显的硝基还原代谢产物。此外尚有一些谢产物未能定性。高致突变性羟基衍生物的检出，显示出硝基多环芳烃在哺乳动物体内可能存在多种代谢活化途径。为进一步的研究奠定了基础。     

2－硝基芴大鼠肝微粒体体外代谢研究

初步研究了在通风条件下，经Ａｒｏｃｌｏｒ１２５４诱导的大鼠肝微粒体酶对２－硝基芴的体外代谢。通过液相色谱、气相色谱、质谱、紫外光谱及红外光谱，首次分离和检测出单羟芴和二羟基芴等代谢产物，但未测得明显的硝基还原代谢产物。     

核分离-滤膜洗脱技术同时检测植物DNASSB与DSB

采用核分离 -滤膜洗脱技术 ,将分离的细胞核在微孔滤膜上裂解后相继用中性溶液和碱性溶液洗脱 ,研究了⁶⁰Co- γ辐射引发的大麦种胚细胞 DNA断裂 .结果显示 ,50 Gy的 ⁶⁰Co- γ辐射主要引发 DNA单链断裂 (DNA SSB) ;50～100Gy的辐射引发的DNA断裂包括单链断裂 (SSB)与双链断裂 (DSB) ;当辐射剂量大于 100Gy时 ,DNA断裂的增加部分则以 DSB为主 .所用的实验方法适用于质地致密的植物材料并可在一次实验中同时检测 DNA的 SSB与 DSB,为植物细胞的 DNA链断裂作为生物标志物应用于环境诱变因子监测提供了基础 .     

2-萘胺的代谢及其活化机理的研究

经诱导的大鼠肝微粒体S9制剂与2-萘胺一起培养,代谢产物经鉴定有以下4种:2-氨基—5-萘酚,2-氨基—6-萘酚,2-氨基—7萘酚和2-氨基—8-萘酚,其生成数量不等.2-萘胺的8-,5-,6-和7-位酚的相对含量依次为52.6％,28.5％,14.0％和4.9％.上述的比例与用双区理论计算和推导的结果是一致的,表明在代谢中芳胺的氨基与异环碳皆起着活化与脱毒的双重作用.     

致癌的生物烷化剂

生物烷化剂是具有烷化有机物分子中某些功能中心为特征的致癌性化合物。生物烷化作用是指烷化剂以其烷基取代靶细胞中生物大分子(DNA、RNA、蛋白质等)特异位置上氢的作用,这一过程毋需在体内先经活化,故生物烷化剂是直接致癌物。DNA.RNA分子中的硷基和蛋白质分子中的某些氨基酸都有被烷化的可能。有些烷化剂还可以整个分子与DNA或RNA分子中的硷基相互作用。     

镉、汞、铅在体内对氨基酸掺入微粒体的特异性抑制作用

本实验采用DL-(~3H)-亮氨酸作为蛋白质合成的原料,从亚细胞水平观察镉、汞、铅在动物体内对肝脏各亚细胞组分蛋白合成的影响。实验结果表明,给雄性大鼠腹腔一次注入2.4mg/kg醋酸镉后72h和一次注给2.0mg/kg氯化汞或100mg/kg醋酸铅后24h,均可不同程度地抑制DL-(~3H)-亮氨酸掺入微粒体蛋白,而对其它组分包括细胞核、线粒体、去微粒体后上清液蛋白中DL-(~3H)-亮氨酸的掺入无明显影响。     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.