阿特拉津降解细菌的直接检测及分离

摘要：利用改良的 SM固体培养基,对受除草剂污染的土壤中阿特拉津降解菌进行了检测、计数及分离。研究发现,在工业污染土壤中,阿特拉津降解菌群成为微生物群落的主要组成部分,而在农业土壤中仅占次要地位。用多重PCR分析了靶向基因trzN 和 atzABC,表明含trzN-atzBC基因组合的降解菌在山东省工业及农业土壤中占主导地位。因为富集偏差的消除,直接分离方法更利于阿特拉津降解菌多样性分析的研究。     

降解除草剂阿特拉津的细菌聚生体的分离和鉴定

将阿特拉津降解速度快但降解不完全的混合菌群与阿特拉津降解完全但降解速度慢的Pseudomonas sp.ADP菌株混合,经过长期驯化培养,筛选到一个能完全降解阿特拉津而且降解速度快的细菌聚生体(bacterial consortium).聚生体含有两个菌株,其中一个菌株来自混合菌群,命名为AD25,另一个是ADP的突变株,命名为Pseudomonas sp.ADP-V.通过16S rRNA基因测序,AD25被鉴定为节杆菌(Arthrobacter sp.).PCR分析和降解实验表明,AD25含有trzN-atzBC基因,能将阿特拉津降解成氰尿酸;ADP-V含有atzDEF基因,是ADP菌株丢失atzABC基因以后的衍生菌,能使氰尿酸进一步降解.由AD25和ADP-V组成的细菌聚生体能快速和完全降解阿特拉津.ADP-V的atzD基因表达和酶动力学实验表明,由于它编码的氰尿酸水解酶(AtzD)的339位蛋氨酸(Met)突变为苏氨酸(Thr),导致酶活力降低从而引起在生长培养基中出现少量氰尿酸积累.     

阿特拉津在金纳米通道中的迁移特性研究

报道阿特拉津在圆柱形的金纳米通道的迁移特性．采用化学沉积法在聚碳酸酯滤膜的孔道里面沉积金,阿特拉津免疫原与载体蛋白形成的复合物通过金纳米通道时产生电流响应,阿特拉津免疫原、阿特拉津与抗体形成的复合物以及其他除草剂通过金纳米通道时产生的电流响应有着明显的不同．该传感器测定阿特拉津的线性范围是2．56×10-8～3．33×10-7mol／L．检测限可达1．70×10-10mol／L．传感器用于实际样品测定,结果满意．     

Two Decades of Triazine Dendrimers

For two decades, methods for the synthesis and characterization of dendrimers based on [1,3,5]-triazine have been advanced by the group. Motivated by the desire to generate structural complexity on the periphery, initial efforts focused on convergent syntheses, which yielded pure materials to generation three. To obtain larger generations of dendrimers, divergent strategies were pursued using iterative reactions of monomers, sequential additions of triazine and diamines, and ultimately, macromonomers. Strategies for the incorporation of bioactive molecules using non-covalent and covalent strategies have been explored. These bioactive materials included small molecule drugs, peptides, and genetic material. In some cases, these constructs were examined in both in vitro and in vivo models with a focus on targeting prostate tumor subtypes with paclitaxel conjugates. In the materials realm, the use of triazine dendrimers anchored on solid surfaces including smectite clay, silica, mesoporous alumina, polystyrene, and others was explored for the separation of volatile organics from gas streams or the sequestration of atrazine from solution. The combination of these organics with metal nanoparticles has been probed. The goal of this review is to summarize these efforts.     

阿特拉津对泥鳅性腺及性别分化相关基因的影响

以泥鳅为材料,首先确定了阿特拉津对泥鳅的急性毒性.在此基础上采用组织学切片和实时荧光定量PCR(qRT-PCR)的方法研究了阿特拉津长期处理对泥鳅性腺形态和性别分化相关基因表达模式的影响,以期准确评估阿特拉津的环境毒性和对水生生物生殖发育的作用.结果表明:阿特拉津对泥鳅的24h、48h、96h的半数致死浓度(LC50)分别为31.60mg/L、26.82mg/L、18.98mg/L,安全质量浓度(SC)为5.8mg/L.随着阿特拉津浓度的增加和处理时间的延长,泥鳅的死亡率明显的升高.通过组织学研究发现高浓度的阿特拉津(2.68 mg/L)处理泥鳅21d能够抑制泥鳅精巢精子的发生,促进卵巢细胞的发育.同时qRT-PCR结果显示:与对照组相比不同剂量的阿特拉津(2.68mg/L,0.268mg/L,0.0268mg/L)能够显著的诱导细胞色素P450芳香化酶基因(cyp19a),类固醇生成因子(sf1)的表达,对抗缪勒氏管激素(amh)有显著的抑制效应.因此,阿特拉津对泥鳅有明显的外源雌激素效应;通过干扰类固醇激素合成基因的表达影响生殖细胞的生成;也通过某种未知的机制干扰性别分化上游基因的表达,从而影响性腺分化.     

Latent solid‐phase extraction with thermoresponsive soluble polymers

The use of soluble thermoresponsive polymers to sequester or scavenge hydrophobic guest molecules from dilute aqueous solutions on heating is described. In these studies, a homopolymer of N‐isopropylacrylamide was shown to sequester 46–83% of a soluble monochlorotriazine from 0.1–10 ppm aqueous solutions when heating above this polymer's lower critical solution temperature (LCST). Substitution of the reactive piperidine‐containing 20:1 copolymer poly(N‐isopropylacrylamide)‐c‐poly[N‐4‐(acrylamidomethyl)piperidine] for this unreactive polymer led to >98% scavenging of these same triazines when heating above this reactive polymer's LCST. The monochlorotriazine guests studied included the herbicide atrazine and two dye‐labeled analogues of this herbicide. In one case, an atrazine analogue was designed so as to contain a dansyl group for fluorescence analysis. In the second case, an atrazine analogue was labeled with a methyl red group to facilitate visual and spectrophotometric analysis. Atrazine concentrations were measured with liquid chromatography–mass spectrometry. The enhanced efficiency of the reactive piperidine‐containing copolymer scavenger in removing triazines from solution is attributed to covalent bond formation by nucleophilic aromatic substitution of the chlorine of the monochlorotriazines by the piperidine nucleophile on the copolymer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 6309–6317, 2004     

Atrazine and Parathion-Methyl Removal by UV And UV/O3 in Drinking Water Treatment

Abstract

The degradation of atrazine and parathion-methyl by UV-light in the presence of O₂(UV/O₂) and by a combination of UV-light and ozone in the presence of O₂(UV/O₂/O₃) was studied at a pilot plant for drinking water treatment. The photolysis rate of parathion-methyl increased with UV/O₂/O₃ compared to the treatment with UV/O₂ only, while the photodecomposition rate of atrazine was not enhanced by the UV/O₂/O₃ combination under the working conditions applied.

In field experiments with a large-scale plant the degradation of atrazine and desethylatrazine was studied at a drinking water supply. The applied ozone dose rates were smaller and the residence time of the liquid phase in the UV-reaction unit was shorter than in the pilot plant. The degradation rate of both atrazine and desethylatrazine increased with increasing ozone dose rates and increasing radiant power. At a continuous flow rate of 70 m³/h of contaminated raw water atrazine could be degraded below the threshold limit for pesticides (0.1[ugrave]g/L) at optimum operation conditions, whereas the resulting desethylatrazine concentration exceeded this limit. At a continuous flow rate of 30 m³/h desethylatrazine could be degraded below the threshold limit, too.     

Soil Type and Herbicides Adsorption

Abstract

Herbicides behaviour in soils greatly depends on adsorption through its influence on degradation and movement. The adsorption intensity depends on both the chemical structure of pesticides, the nature of soil constituents and soil physico-chemical factors such as the pH. In this paper, the role played by these factors is analysed and used to evaluate the possible use of soil surveys for assessing adsorption behaviour of pesticides in soils. The analysis is based on adsorption measurements of three herbicides (atrazine, terbutryn and 2,4-D) by several soils differing in their mineralogical composition, organic matter content and pH. Using statistical analysis, it is shown that some relations can be defined between soil types and adsorption behaviour. These relations are strongly dependent on the electrical state of the herbicide molecule (cationic, anionic and neutral).     

土壤中莠去津及其降解产物的提取及高效液相色谱-质谱分析

建立了高效液相色谱-质谱联用(HPLC-MS)选择离子检测(SIM)分析环境土样中的痕量莠去津及其降解产物脱乙基莠去津(deethylatrazine,DEA)、脱异丙基莠去津(deisopropylatrazine,DIA)、羟基化莠去津(HA)的方法。土样用双蒸水超声提取,然后用Waters Oasis MCX固相萃取小柱富集纯化土样提取液,测得莠去津及其降解物在不同加标浓度(4.5~120 ng/g)下的回收率为：莠去津40.4%~82.0%,DEA 60.6%~86.5%,DIA 69.2%~86     

离子色谱法测定三嗪类除草剂

本文报道利用离子色谱法同时分离分析莠去津、扑草净、扑灭通除草剂的方法 .采用 CG- 12 (2mm)分离柱 ,紫外检测器 ,用一系列的淋洗液 .实验在 0 .2 0 mol·L-1H2 SO4 +2 5 %CH3CN条件下 ,得到最佳分离效果 .莠去津、扑草净、扑灭通的测定均有良好的线性 .它们的检测限分别为莠去津为 3.13×10 -2 μg· m L-1,扑草净为 4 .39× 10 -2 μg· m L-1,扑灭通为 1.36× 10 -2 μ/ m L-1,此方法可用于废水中除草剂的测定 ,样品的回收率在 96.0 0 %～ 10 5 .32 %之间 .