久效磷对海洋微藻毒性机理的初步研究III.超氧化物歧化酶和过氧化物酶活性的变化

报道了久效磷对3种海洋微藻细胞内2种清除活性氧的关键性酶--超氧化物歧化酶和过氧化物酶活性的影响.结果显示:1.在久效磷的胁迫下,扁藻和三角褐指藻细胞的超氧化物歧化酶(SOD)活性均表现出下降的总变化趋势,而叉鞭金藻细胞的SOD活性时而上升,时而下降,在整个胁迫过程中呈现出无规律性的变化.2.随着久效磷胁迫时间的延长,3种微藻细胞的过氧化物酶活性均逐渐下降,表现出相同的变化规律性.这说明不同的藻种,久效磷对其细胞内酶活性的影响不尽相同.推测超氧化物歧化酶和过氧化物酶(POD)活性的降低是微藻细胞内过量产生活性氧,进而引起藻细胞膜脂过氧化伤害的主要原因之一.     

久效磷降解菌的分离及其酶促降解特性研究

从某农药厂废水处理池的污泥中分离到1株久效磷高效降解菌株M-1,经过对其形态特征、生理生化、以及16S rDNA序列分析,该菌株初步鉴定为Paracoccus sp..M-1能以久效磷作为唯一碳源生长,24 h对100 mg·L^-1久效磷的降解效率为92.47%.久效磷降解酶定域表达试验表明该酶为胞内酶,组成表达.久效磷酶促降解的最适反应pH为8.0,最适反应温度为25 ℃;其米氏常数（K_m）为0.29 μmol·mL^-1,最大降解速率(V_max)为682.12 μmol·(min·mg)^-1.久效磷降解酶热稳定性差,碱性条件下能够保持较高降解活性.     

久效磷对黄鳝过氧化氢酶和Na+, K+-ATP酶活性的影响

采用静态急性毒性试验方法,研究了久效磷对黄鳝的鳃、肝脏和肾脏组织中过氧化氢酶(CAT)和Na , K -ATP酶活性的影响. 结果表明:在水温为(20±2) ℃的条件下,久效磷对黄鳝的96 h LC50为3.27 mg/L. 经0.25,0.50,1.00和2.00 mg/L的久效磷暴露96 h后,0.25和0.50 mg/L暴露组黄鳝3种组织中的CAT活性均比对照组高,其中0.25 mg/L暴露组有显著升高(P《0.05);1.00和2.00 mg/L暴露组的CAT活性受到明显抑制,其中2.00 mg/L暴露组与对照组相比抑制作用显著(P《0.05);不同质量浓度的久效磷对黄鳝3种组织中的Na , K -ATP酶活性均表现出抑制作用,Na , K -ATP酶活性对久效磷的敏感性由大到小的顺序为鳃》肾脏》肝脏.     

碘离子选择电极快速测定食盐中碘的含量

利用碘离子选择电极,以0．1mol／LKNO（3^-）0.01mol／L酒石酸为总离子强度调节荆、Na2SO3为还原保护剂,将加碘食盐中的10（3^-）还原为I^-,在双液接饱和甘汞电极为参比电极的条件下,采用直接电位法和标准曲线法直接测定了溶液中的碘含量,实验结果表明,本方法线性范围10^（-1）～10^（-7）mol／L,检测下限4.6×10^（-8）mol／L,样品具有较好的回收率（98．2％-100．7％）,可以用此方法测定食盐中I^-的含量。     

嵌入式碳纳米管电极差分脉冲伏安法测定湖泊沉积物中铅

制备嵌入式多壁碳纳米管修饰石墨电极（ESCFE）,利用循环伏安法研究铅（Pb）的电化学行为及反应机理,结果表明,铅在修饰电极表面出现了一对明显的准可逆的氧化还原峰,发生了2质子的电化学氧化反应。用差分脉冲伏安法研究了铅离子浓度与其峰电流的线性关系,线性范围为1．8×10^-7～1．0×10^-5g／L,线性方程为：ipa（μA）=0．12＋1．471c×10^6（g/L）,r=0．9999,检出限为6．0×10^-8g／L,RSD％为1．015（n=5）。利用本法对湖泊沉积物中铅进行测定,样品铅含量：0．218～0．6317mg／kg,RSD：3．3％～6．2％,加标回收率：94．3％-106．6％。     

海水条件下固定化乙酰胆碱酯酶(AChE)的基本性质研究

以固定化AChE为识别元件,以pH电极为换能器构成流动注射型生物传感器,由蠕动泵持续输送海水,然后向体系中注入一定量的底物溶液,所产生的模拟信号经过A/D转换装置后成为数字信号(电位),并在计算机上显示.结果表明,该固定化酶在同种海水中所表现的酶活之间具有良好的重现性(RSD=2.33%,n=12);底物(碘化硫代乙酰胆碱)溶液的最佳浓度和注射量分别为41.6 mmol/L和40 μL,过量底物对此固定化酶有抑制作用;海水的适宜流速为0.39 mL/min;环境条件对固定化酶的活性有一定影响,在盐度为24.9、温度为30℃时,固定化酶具有最高活性.     

酶电极法测有机磷农药

用戊二醛将胆碱脂酶和牛血清白蛋白共价交联到玻璃电极上，制成酶电极，除测底物乙酰胆碱外，还可测酶抑制剂—有机磷农药。各农药的检出限和线性范围与它对酶的抑制程度有关，表现出一定的选择性，辛硫磷的检测限是4．9×10-8mol／L，敌敌畏是5×10－7mol/L，叶蝉散是8．5×10－5mol/L，发现在20～45℃范围内温度对酶电极活性影响不大，电极寿命可达50天。     

羟基致死船舶压载水微生物的生化影响研究

试验表明羟基比值浓度达到0．63mg／L左右时，足以杀死压载水微生物。在此浓度下也会引起微生物的糖、脂质、蛋白质、核酸、酶等发生强烈的化学反应。脂质过氧化物含量上升为原来的3倍；总蛋白质减少了33．4％；核酸中RNA、DNA分别减少了46．9％、77．0％；葡萄糖却增加了1倍，羟基破坏了多糖，使之降解为单糖；过氧化物酶含量减少了21．9％；超氧化物歧化酶减少了54．2％；分离微生物后海水中过氧化氢酶、超氧化物歧化酶分别减少了83．1％、33．2％，上述生化试验资料清楚表明了羟基对微生物三大基本分子(核酸、蛋白质、葡萄糖)、抗氧化酶系(过氧化酶、过氧化氢酶、超氧化物歧化酶)以及脂质均有强烈的破坏作用，这也是致死压载水微生物的主要原因。     

检测水中有机磷农药的酶传感器

采用丝网印刷技术制作厚膜型电极,通过交联法将乙酰胆碱酯酶固定在电极上,开发快速检测水中有机磷农药的酶传感器.采用循环伏安法对电极所做的检测结果表明电极彼此间的差异在10%以内,具有较好的一致性.通过在交联剂、酶和底物等方面优化传感器的工作参数,确定了戊二醛、酶和底物的浓度分别为0.2%、0.5 mg/mL和10 mmol/L时,传感器响应最好.在交联固定酶的情况下,根据酶活受到有机磷抑制的原理,采用时间-电流法对特丁硫磷和对硫磷进行了检测.结果表明:这2种有机磷的检测限都可以达到1 ng/mL,线性区间1～10 000ng/mL.在物理吸附固定酶的情况下,采用循环伏安法对特丁硫磷进行了检测.结果表明:采用循环伏安法检测的灵敏度比采用时间-电流法的灵敏度要高.     

久效磷对海洋微藻毒性机理的初步研究Ⅲ.超氧化物歧化酶和过氧化物酶活性的变化

报道了久效磷对３种海洋微藻细胞内２种清除活性氧的关键性酶———超氧化物歧化酶和过氧化物酶活性的影响．结果显示：１在久效磷的胁迫下，扁藻和三角褐指藻细胞的超氧化物歧化酶（ＳＯＤ）活性均表现出下降的总变化趋势，而叉鞭金藻细胞的ＳＯＤ活性时而上升，时而下降，在整个胁迫过程中呈现出无规律性的变化．２随着久效磷胁迫时间的延长，３种微藻细胞的过氧化物酶活性均逐渐下降，表现出相同的变化规律性．这说明不同的藻种，久效磷对其细胞内酶活性的影响不尽相同．推测超氧化物歧化酶和过氧化物酶（ＰＯＤ）活性的降低是微藻细胞内过量产生活性氧，进而引起藻细胞膜脂过氧化伤害的主要原因之一．     

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.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

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

ＲｅｍｏｖａｌｏｆｈｅａｖｙｍｅｔａｌｓｆｒｏｍｓｅｗａｇｅｓｌｕｄｇｅｂｙｌｏｗｃｏｓｔｉｎｇｃｈｅｍｉｃａｌｍｅｔｈｏｄａｎｄｒｅｃｙｃｌｉｎｇｉｎａｇｒｉｃｕｌｔｕｒｅＷｕＱｉｔａｎｇ，ＮｙｉｒａｎｄｅｇｅＰａｓｃａｓｉｅ，ＭｏＣｅｈｕｉＦ...