Mechanistic aspects the dioxin (aryl hydrocarbon) receptor

The Ah receptor mediates the toxicological responses of 2,3,7,8-TCDD and related compounds. Receptor-deficient animals were shown to be resistant to the toxic effects of dioxin, although there is also evidence for the existence of a receptor-independent pathway for dioxin-induced toxicity. In the cytosol the receptor is present in a non-activated ligand binding conformation. Association with Arnt in the nucleus turns the receptor complex into a ligand activated form. The physiological role of the receptor is not yet understood; however, the conservation of the receptor in a wide range of animal species (including humans) suggests a fundamental role in cellular physiology.     

马铃薯淀粉废水高活性絮凝菌的分离鉴定

从马铃薯淀粉废水和黄河污水排放口附近的污泥中分离得到300株菌,对所分离的菌株进行分离纯化,初筛和复筛,得到6株絮凝活性在60%以上的细菌,对6株细菌进行形态特征分析,将复筛的6株细菌悬液按照等体积的比例进行复配,絮凝率最高的混合菌为N1和N2,达到96.41%,选取絮凝率80%以上的4组构建菌中的5株细菌,对其进行16S rDNA序列分析,鉴定结果为N1短杆菌属（Brevibacterium sp.）、N2短小芽孢杆菌（Bacillus pumilus）、N3希瓦氏菌属（Shewanella sp.）、N4赖氨酸芽孢杆茵（Lysinibacillus fusiformis）、N5解鸟氨酸拉乌尔菌（Raoultella ornithinolytica）。     

Key amino acids in the aryl hydrocarbon receptor predict dioxin sensitivity in avian species

Dioxin-like compounds are toxic to most vertebrates, but significant differences in sensitivity exist among species. A recent study suggests that the amino acid residues corresponding to Ile324 and Ser380 in the chicken aryl hydrocarbon receptor 1 (AHR1) are important determinants of differential biochemical responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in chickens and common terns. Here, we investigate whether the identity of these amino acid residues can predict embryonic sensitivity to dioxin-like compounds in a wide range of birds. AHR1 sequences were determined in species for which sensitivity data were available. Of all the species surveyed, chickens were unique in having the Ile/Ser genotype and were also the most sensitive to dioxin-like compounds. Turkeys, ring-necked pheasants, and Eastern bluebirds (intermediate Ile/Ala genotype) were less sensitive than chickens but more sensitive than American kestrels, common terns, double-crested cormorants, Japanese quail, herring gulls, or ducks (Val/ Ala genotype). Our work suggests that key amino acids in the AHR1 ligand binding domain are predictive of broad categories of dioxin sensitivity in avian species. Given the large degree of variation in species sensitivity and the paucity of species-specific toxicity data, a genetic screen based on these findings could substantially improve risk assessment for dioxin-like compounds in wild birds.     

Construction of a reporter yeast strain to detect estrogen receptor signaling through aryl hydrocarbon receptor activation

The activation mechanism of estrogen receptor (ER) signaling by association with the aryl hydrocarbon receptor (AhR) was elucidated recently (Ohtake, et al., Nature 2003, 423, 545). In the present study, we established a reporter yeast strain to evaluate this ER signaling by association with the activated AhR. This yeast strain expresses human ER and AhR, and has a reporter plasmid with estrogen response elements. With this yeast strain we assayed ER activation by various AhR ligands, i.e., 2,3,7,8-tetrachlorodibenzo-p-dioxin, benzo[a]pyrene, 3-methylcholanthrene, beta-naphthoflavone, and indirubin. All these ligands induced ER activation dose-dependently and their EC50 values were 60, 180, 130, 26, and 0.5 nM, respectively. Then, we measured the activity in water collected at 5 localities in the Ishizu River system in Japan. The activities of water samples ranged from 4.8 pmol/L (1.3 ng/L) to 52 pmol/L (14 ng/ L) (17beta-estradiol (E2) equivalent). These values were higher than those measured with the yeast for ER activation through direct ligand binding to ER. The direct ER ligand binding activities of the water samples ranged from 2.5 to 5.3 pmol/L (E2 equivalent). We also measured AhR activation of the water samples using a reporter yeast for AhR ligand activity. The activities ranged from 102 to 472 pmol/L (beta-naphthoflavone equivalent). These results indicate that the water samples contain substances that bind to AhR, and these substances contribute to ER signaling through AhR activation in the yeast reporter strain. This yeast reporter strain should be a useful tool to evaluate direct and indirect ER activation by environmental samples.     

印染废水处理技术研究进展

介绍了各种印染废水处理的方法:物理化学法、化学法及生物技术法,分析了各类技术方法的机制、处理效果及其优缺点。根据印染废水特性,采用不同处理方法的组合工艺技术,可实现对印染废水的彻底处理。以生物技术法为主体,辅以物理化学处理的组合处理工艺已逐渐成为目前印染废水处理的主流工艺。     

染色废水处理改造方案研究与实施

为更好地发展当地经济,提高人居环境,响应姜堰市委、市政府正在努力创建"生态市"的号召,江苏嘉晟染织有限公司决定对染色废水处理系统实施再次改造。首先介绍了公司目前染色废水处理现状,指出了公司废水处理系统中存在的问题,并提出需要整改的项目,然后对比三套废水处理系统改造方案,综合考虑,最终确定江苏亚同环保科技有限公司设计的方案,实施并完成计划的染色废水改造工程。从改造完成到目前为止,在有关的环境行为评比工作中,我公司都名列前茅,连续几年被环保部门评为"绿色等级"企业。     

聚酰胺-胺在印染废水处理中的应用

使用聚酰胺-胺处理印染废水,研究了聚酰胺-胺的代数、溶液酸度以及聚酰胺-胺用量对色度和COD去除率的影响.研究表明:聚酰胺-胺对印染废水的色度和COD去除率具有良好的治理效果,在pH值5.0左右,聚酰胺-胺50 mg/L时,脱色率和COD去除率分别达到96.4%和92.7%.另外,聚酰胺-胺处理对高浓度的印染废水具有用量少,处理效果好,操作简便等优点.     

活性染色废水的光电催化降解

采用以负载改性纳米TiO2的活性炭颗粒为填充电极的三维光电催化反应装置,对活性染料染色废水进行光电脱色处理.研究了活性碳用量、电压、pH值和无机盐对脱色反应的影响.将脱色后的染色废水回用于棉织物染色,对染色织物的颜色特征进行了比较.结果表明,脱色后废水可以回用于织物的活性染料染色;在活性炭用量适中时,染色废水的脱色率达最高;pH值为中性时,对染色废水的脱色几乎无影响;添加氯化钠有利于脱色效果的改善.     

Camellia sinensis tea melanin suppresses transformation of the aryl hydrocarbon receptor and prevents against dioxin-induced toxicity in mice

The suppressive effects of Camellia sinensis tea melanin (CSTM) on transformation of aryl hydrocarbon receptor (AhR) induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were disclosed for the first time. CSTM strongly inhibited TCDD-induced toxicity with IC₅₀ equalling 20.4 μg mL⁻¹. Daily administration of CSTM (40 mg kg⁻¹, p.o.) prevented TCDD-induced body weight loss, ameliorated TCDD-induced mortality and prevented TCDD-induced hepatomegaly and thymic atrophy. Co-administration of CSTM significantly inhibited TCDD-induced hepatic CYP1 A1 activity. CSTM retarded transformation of AhR in vitro. In animals treated with CSTM, the antibody-secreting cells produced significantly (P < 0.05) more antibodies (32–34%) than the antigen control. Administration of TCDD caused a suppression of antibody-forming cells of 29–33% against the antigen control level. Co-administration of CSTM restored immunity to the control level. We demonstrated that CSTM directly competed with TCDD during the transformation of AhR and suppressed the downstream activation of genes associated with TCDD toxicity.     

漂染废水处理及回用

通过清污分流，利用混凝-CASS-澄清砂滤工艺处理漂染厂废水.工程运行结果表明：经分流后，CODCr平均865.4 mg/L，色度356倍的高浓度废水，处理后分别降至62.9 mg/L和17倍，实现了达标排放;低浓度废水CODCr平均216.9 mg/L，色度85倍，处理后分别降至3.1 mg/L和1倍，直接回用于生产，废水回用率达到近70 %.     

印染废水处理中的自控系统

阐述一种PLC和上位机两级控制结构的自动化控制系统在印染废水处理工艺中的应用.整套控制系统由上位机系统,可编程序控制器系统(PLC),I/0柜,就地操作箱,一次仪表和电源系统等组成,重点介绍了该系统的性能,处理污水工艺的方式以及该系统的特点.     

Antagonistic effect of the Ainu-selected traditional beneficial plants on the transformation of an aryl hydrocarbon receptor

Transformation of an aryl hydrocarbon receptor (AhR) is the initial step to express the multiple toxicity of halogenated and polycyclic aromatic hydrocarbons (HAHs and PAHs) including dioxins. Therefore, it has been suggested that suppression of the transformation induced by HAHs and PAHs leads to reduce their toxicological effects. In this study, the antagonistic effect of 110 indigenous plants (192 plant parts) used as medicine and/or food by the Ainu on the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced AhR transformation was investigated. Of these, a stalk of Aralia elata (Miq.) Seemann and a bark of Fraxinus mandshurica Rupr. var. japonica Maxim. exhibited the strong antagonistic effect in a dose-dependent manner. An antioxidative activity and polyphenol content were also measured, and the strong correlation (r= 0.96) between these two parameters could be confirmed. However, correlation coefficients of the antagonistic effect of 192 extracts compared to their antioxidative activity and polyphenol content were 0.17 and 0.20, respectively. These results suggest that the Ainu-selected traditional beneficial plants are useful source for findings of novel AhR antagonists, and the antagonistic activity of these plants may be independent on their antioxidative activity and polyphenol content. PRACTICAL APPLICATION: Our findings lead to discovery of the valuable plants used by the Ainu and the novel active compounds useful for human's life, and furthermore, may contribute to the development of new medicines and functional foods.     

Isolation and identification of ligands for the goldfish testis androgen receptor in chemical recovery condensates from a Canadian bleached kraft pulp and paper mill

This study builds on a series of investigations characterizing substances in kraft mill chemical recovery condensates that depress sex steroids in fish. Here, incubations of goldfish testis androgen receptors (AR) with condensate extracts were used to investigate the potential role of androgens in hormone depressions. Condensates contained variable levels of AR ligands, with the highest amounts in nonpolar extracts of filtered solids prior to solid phase extraction (SPE). High pressure liquid chromatography (HPLC) fractionation recovered the majority of activity in one fraction, with ligands detected in three additional fractions. Gas chromatography mass spectrometry analysis of the most active fraction confirmed the two most abundant components as the diterpenes manool and geranyl linalool. Manool exhibited a relative affinity for the AR that was 300 fold less than testosterone and accounted for 26% of total filtered solids activity. Geranyl linalool exhibited no affinity for the AR. Three additional diterpenoid families were tentatively identified as principal components of the three other androgenic HPLC fractions. Compared to condensates, final effluent had 3000 fold less androgenic activity, with <1% attributable to manool. Putative androgens previously associated with mill effluents (androstenedione and androstadienedione) and progesterone were not detected; however, additional condensate diterpenes suspected as androgens were identified in final effluent. This study is the first to confirm nonsteroidal cyclic diterpenes as androgenic at pulp mills. A major in-mill source of these substances was identified, and the role of androgens in mill effluents affecting fish reproduction was reinforced.     

印染废水治理工程措施

为有效地处理印染废水,工程措施需要生化、物化、化学以及其他方法的组合.介绍了典型的印染废水治理工程措施,包括物化+生化组合与物化+生化+深度处理组合、生化+物化组合.COD与色度的去除效果以及运行成本等是选择印染废水治理措施时主要考虑的因素:在选择废水处理工艺时,要根据进水COD浓度、色度大小以及COD、色度的排水标准采确定.工程运行的成本与处理工艺和废水的处理难易成一定的比例关系.COD越高,处理成本也越大.在工程运行中,需要优化运行参数与措施,降低处理成本.指出了废水资源化处置是治理技术今后发展的方向之一.     

双膜法印染废水回用案例

通过对达标排放的印染废水（4 000 t/d）进行双膜法处理,中水回用率可达至60%~70%,再生水的水质稳定可靠,勿需任何过滤或软化处理,即可回用于高质量的印染生产中,实现了废水的再生利用。     

印染废水处理原则及方法

印染废水是高浓度、难降解的有机废水,介绍了废水处理原则及处理方法的选择;分析了各类印染废水处理的一般工艺,包括棉及棉混纺印染、毛印染、丝绸染整、麻染整、化纤染整和蜡染的废水处理工艺;提出了印染废水处理中需要注意的几个问题,如水解酸化池的设计、色度的处理方法比较等;指出了印染废水处理采用新技术、新药剂的原则以及中试的必要性。     

印染废水的治理现状及展望

从物化法和生物法角度概述了印染废水处理方法的研究现状和最新进展,介绍了各种方法处理印染废水的实例,并指出了各方法的优缺点和技术关键最后,对印染废水处理技术的发展方向进行了展望,努力进行印染行业的产业结构调整,加强印染设备改造及印染新工艺、新技术的开发应用,积极推行清洁生产,开展资源综合利用,采用低废、无废工艺、高效的设备和完善的管理,从源头上削减废水与污染物的产生,使得印染废水污染这一问题得到彻底解决.     

印染厂废水余热的回收利用

印染行业是用能大户,需要煤、汽、水、电、烧碱等,面广量大,工作中稍有疏忽,就会造成极大的浪费,节能牵涉到印染工艺的技术创新和产品的升级换代,也贯穿印染设备更新改造的全过程。印染厂生产排放的废水中含有大量的热能,选择合适的换热设备和回收措施,将其热能回收再利用具有很高的经济价值。