质粒pATZ-1的纯化和分子大小的测定

通过 CsCl- EB( 溴化乙锭) 密度梯度离心, 从降解除草剂阿特拉津的假单胞菌 AD1 菌株中分离并纯化出质粒pATZ- 1. 该质粒经 EcoRI消化产生 14 个限制片段, 以DNA 的 Hind片段为分子大小的标准,用作图法测出上述14 个片段的大小之和即pATZ-1 的分子大小为125 kb.     

假单胞菌AD1菌株对阿特拉津污染土壤的生物修复

向每克土壤含1mg阿特拉津的模拟污染土壤中接种假单胞菌AD1菌株,补加适量碳源和磷源,30℃培养4周以后,96％的阿特拉津被去除。     

Thermal Decomposition of Triazine Herbicides II. 6-Chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine (atrazine) and its metabolites

Thermal degradation of atrazine and its metabolites has been investigated using a thermogravimetric technique(TG) with the application of three types of crucibles: opened, Knudsen type and labyrinthtype, and non-isothermal DSC method, using hermetically closed and opened alumina sample pans. The great influence of decomposition conditions (the crucible type) on thermal degradation was observed. TG analysis showed that the degradation process of atrazine took place in three stages. The increase of amino groups in triazine ring increases the amount of non-volatile thermal degradation products by association. The presence of chlorine substituent facilitates the forming of products with low volatility. Hydroxyatrazine decomposes only in one stage process. The dealkylation process observed in hermetical sample pans (DSC) was two-stage and in open sample pans one-stage process. This revised version was published online in July 2006 with corrections to the Cover Date.     

Rapid preparation of molecularly imprinted polymers by custom‐made microwave heating for analysis of atrazine in water

The rapid preparation of an atrazine‐imprinted polymer in a cost‐effective custom‐made microwave reactor was demonstrated. The polymerization reaction was accelerated by microwave heating, and the preparation time was greatly shortened (to 1 h). The resulting polymer was successfully applied as solid‐phase extraction adsorbent for the selective extraction and preconcentration of atrazine in environmental water samples. The binding capacity of the polymer was 1.11 mg/g polymer. The polymer provided selectivity with higher recovery of atrazine than of other interfering related contaminants. The proposed method had good limits of detection and quantitation at 0.20 and 0.60 ng/mL, respectively. The recoveries were from 83 to 89% at two spiking levels, with relative standard deviations less than 5%. This method was successfully applied to determine the atrazine levels in environmental water samples.     

乙莠悬浮剂的气相色谱分析

乙莠悬浮剂由乙草胺和莠去津两种除草剂复配加工而成，本文选择５％ＯＶ－１７为固定液邻苯二甲酸二戊酯示物，用气相色谱法在同一条件下同时测定出两种除草剂的有效含量。乙苯胺和莠去津的平均回收率分别为１００．０１％和１００．０５％，标准偏差分别为０．０４１％和０．０３６％。     

溶液制备过程引入的甲醇对阿特拉津UV光氧化速率和降解机理的影响

在低压汞灯（253.7 nm）光照条件下，研究了样品制备过程中引入的有机溶剂甲醇对目标有机物阿特拉津光氧化降解速率的影响规律，并系统地分析了其影响机理.研究结果表明：反应体系中含有低浓度（<0.1%）有机溶剂甲醇时，不会对阿特拉津在单独UV工艺中的降解动力学产生影响；对UV/H₂O₂工艺中阿特拉津降解动力学的影响较小，但此含量的甲醇却能显著地降低阿特拉津在UV/TiO₂工艺中的降解速率.甲醇对阿特拉津在不同光氧化工艺中降解动力学的影响是甲醇与阿特拉津竞争光量子、改变溶液极性和淬灭活性氧化物种等作用的综合结果，但反应体系中甲醇的存在及含量未改变阿特拉津降解产物的种类及降解途径.本研究的结果可为探索溶液制备时引入到反应体系中的有机溶剂对有机目标物光氧化速率的影响提供新的研究视角，同时也能为文献中目标物配制在不同溶剂中的降解速率差异提供合理解释.     

Screening and Monitoring of Herbicides Behaviour in Soils by Enzyme Immunoassays

Abstract

A simplified approach to screen cropland for residues of atrazine and its main metabolite deethylated atrazine has been presented. A time-saving and cost-effective screening method has been developed using an aqueous extraction step. The measurement of the extracts was done by immunoassay technique (ELISA). Antibodies against atrazine and deethylated atrazine were used in the study. The overall detection limit of the analysis of atrazine residues in soil is 1 μg kg^?1 and 2 μg kg^?1 for its deethylated metabolite, respectively. It is shown that this approach yields adequate information to judge the ground-water hazard potential of treated fields.     

阿特拉津降解菌Enterobacter sp.的基因差异分析

筛选并分析生物降解菌Enterobacter sp.在阿特拉津作用下的差异基因。以Enterobacter sp.BIDMC 29基因组为参考,利用高通量测序技术,对阿特拉津降解菌株和对照菌株进行转录组测序分析。结果表明,共有368个基因表现出显著差异,其中上调基因231个,下调基因137个。在差异基因GO富集分析的前30个条目中,尿嘧啶分解代谢、氮利用、硝酸盐同化、硫化氢生物合成、裂解酶活性和过氧化物酶活性等相关基因表现富集。Pathway分析显示,差异基因涉及70条代谢途径,与氮代谢、氨基酸合成和代谢、ABC转运蛋白、丙酮酸代谢等过程有关。菌株通过调节基因表达来提高对阿特拉津的降解能力,为进一步解析阿特拉津的代谢机制奠定基础。     

土壤中阿特拉津降解实验研究

通过批实验确定了阿特拉津在不同土壤样本中的降解速率，同时对各土壤特性与降解速率的相关性进行了统计分析，并比较了阿特拉津在灭菌土壤与未灭菌土壤中的降解过程．结果表明：土壤中阿特拉津降解速度缓慢，而且实验土壤对阿特拉津的吸附作用较弱，故阿特拉津的施用对当地浅层地下水和地表水资源存在较大威胁；非生物降解和生物降解所起的作用相当；实验地区阿特拉津的降解参数服从正态分布；在水平α=0．05下，降解速率与已知的几种土壤特性及吸附参数的相关性较弱，     

Atrazine degradation by Pseudomonas strain ADP entrapped in sol-gel glass

Sol-gel entrapment was evaluated as a method for immobilization of an atrazine degrading Pseudomonas. It was found that the bacterium lost much of its atrazine degrading activity upon immobilization. However, partial activity could have been restored by amendment of nutrients. Bacteria immobilized using a prehydrolysis technique for the preparation of the sol-gel, retained better activity in comparison to bacteria immobilized using a composite calcium alginate/sol-gel procedure. Further study is underway to improve the activity of sol-gel entrapped bacteria.