3种增塑剂单独和联合暴露对MCF-7细胞增殖的影响

为了探究结构差异较大、应用较为广泛的几类增塑剂雌激素活性的联合效应,选择邻苯二甲酸二丁酯(DBP)、双酚A(BPA)和壬基酚(NP)作为邻苯二甲酸酯、双酚A类和烷基酚类增塑剂的代表物进行试验.用DBP、BPA和NP单独及两两混合处理MCF-7细胞.采用MTT法检测培养24h、48 h、72 h和96h时的细胞增殖情况.采用流式细胞术检测药物培养48h后的细胞生长周期分布,并计算细胞增殖指数(PI).运用效应叠加模型(ES)判定联合效应类型.结果表明,在单独暴露试验中,DBP、BPA和NP组PI均大于1,且均能提高S期(DNA合成期)细胞比例.因此,DBP、BPA和NP均能显著促进MCF-7细胞增殖.混合暴露试验中,1)DBP和BPA在MTT试验中24h、48h、72 h和96h时的效应叠加指数(ESI)分别为1.013 9、1.023 8、0.9999、1.010 8,在流式细胞仪试验中ESI为1.014 1.因此,DBP和BPA的雌激素活性联合效应为加和作用.2)DBP和NP在MTT试验中24 h、48 h、72 h和96 h时的ESI分别为1.004 0、1.008 6、1.011 5、1.010 3,流式细胞仪试验中ESI为0.997 0.因此,DBP和NP的雌激素活性联合效应为加和作用.3)BAP和NP在MTT试验中24h、48 h、72 h和96h时的ESI分别为0.980 6、0.981 8、0.977 7、0.973 3,流式细胞仪试验的ESI为0.912 8.由此可知,BPA和NP的雌激素活性联合效应为拮抗作用.因此,可以采用MCF-7细胞增殖试验研究环境污染物雌激素活性联合效应.     

Laccase-catalyzed bisphenol A oxidation in the presence of 10-propyl sulfonic acid phenoxazine

The kinetics of the Coriolopsis byrsina laccase-catalyzed bisphenol A(BisA) oxidation was investigated in the absence and presence of electron-transfer mediator 3-phenoxazin-10-ylpropane-1-sulfonic acid(PPSA) at pH 5.5 and 25°C. It was shown that oxidation rate of the hardly degrading compound BisA increased in the presence of the highly reactive substrate PPSA. The increase of reaction rate depends on PPSA and BisA concentrations as well on their ratio, e.g., at0.2 mmol/L of BisA and 2 μmol/L of PPSA the rate increased 2 times. The kinetic data were analyzed using a scheme of synergistic laccase-catalyzed BisA oxidation. The calculated constant, characterizing reactivity of PPSA with laccase, is almost 1000 times higher than the constant, characterizing reactivity of BisA with laccase. This means that mediator-assisted BisA oxidation rate can be 1000 times higher in comparison to non-mediator reaction if compounds concentration is equal but very low.     

A screening assay for thyroid hormone signaling disruption based on thyroid hormone-response gene expression analysis in the frog Pelophylax nigromaculatus

Amphibian metamorphosis provides a wonderful model to study the thyroid hormone (TH) signaling disrupting activity of environmental chemicals, with Xenopus laevis as the most commonly used species. This study aimed to establish a rapid and sensitive screening assay based on TH-response gene expression analysis using Pelophylax nigromaculatus, a native frog species distributed widely in East Asia, especially in China. To achieve this, five candidate TH-response genes that were sensitive to T3 induction were chosen as molecular markers, and T3 induction was determined as 0.2 nmol/L T3 exposure for 48 hr. The developed assay can detect the agonistic activity of T3 with a lowest observed effective concentration of 0.001 nmol/L and EC50 at around 0.118–1.229 nmol/L, exhibiting comparable or higher sensitivity than previously reported assays. We further validated the efficiency of the developed assay by detecting the TH signaling disrupting activity of tetrabromobisphenol A (TBBPA), a known TH signaling disruptor. In accordance with previous reports, we found a weak TH agonistic activity for TBBPA in the absence of T3, whereas a TH antagonistic activity was found for TBBPA at higher concentrations in the presence of T3, showing that the P. nigromaculatus assay is effective for detecting TH signaling disrupting activity. Importantly, we observed non-monotonic dose-dependent disrupting activity of TBBPA in the presence of T3, which is difficult to detect with in vitro reporter gene assays. Overall, the developed P. nigromaculatus assay can be used to screen TH signaling disrupting activity of environmental chemicals with high sensitivity.     

多级A／O膜生物反应器污泥活性研究

采用一种新型的多级A／O膜生物反应器处理污水,对该工艺的污泥活性进行了研究。结果表明,VSS／SS在实验过程中呈较弱的下降趋势,多级A／O池曝气室污泥比硝化速率逐室下降,但各缺氧室污泥比反硝化速率基本一致;污泥释磷、聚磷过程在30 min和1 h内基本完成,反硝化聚磷试验表明污泥中存在DPB的富集,反硝化作用是反硝化细菌与DPB共同作用的结果。     

Chemopreventive effects of ellagic acid against genotoxicity induced by benzo(a)pyrene

Benzo(a)pyrene (B(a)P) is a commonly used indicator for polycyclic aromatic hydrocarbons (PAHs) contamination. The use of certain phytochemicals and some polyphenolic compounds proved to be effective in blocking PAH-induced effects. The aim of the present study was to examine the possible inhibitory effects of ellagic acid (EA), present in berries and nuts, against B(a)P-mediated toxicity using in vitro and in vivo test systems. In vitro method included the Ames test, using Salmonella typhimurium tester strain TA100. In vivo experiments were based on mouse bone marrow micronucleus (MN) assay and immunoblotting. EA produced a decrease in the number of revertant colonies against B(a)P in the Ames assay. Further, there was a reduction in the mean number of micronucleated polychromatic erythrocytes in the presence of EA in the co-treatment protocol of the MN test. Western blotting results showed downregulation of CYP450 isoform CYP1A1 which prevented bioactivation of B(a)P. Thus, the present study demonstrates antimutagenic role played by EA against the mutagenic activity of B(a)P in both in vitro and in vivo systems.     

呼和浩特市可镇污水处理厂工程设计

呼和浩特市可镇污水处理厂近期建设规模1.0×104m3/d,远期总规模2.5×104m3/d。污水处理主体工艺采用组合式A2/O生化池+砂滤,污泥处理采用污泥贮池+带式浓缩脱水一体机,尾水采用液氯消毒,设计出水水质执行GB 18918—2002《城镇污水处理厂污染物排放标准》一级A排放标准。介绍了该工程的工艺流程、设计参数,总结分析了工艺设计的技术特点。同时阐述了针对低温条件下的运行保障措施和要求,为寒冷地区同类污水处理厂的设计提供参考和借鉴。     

GJB150A在某通信装备低温试验中的应用研究

由于是剪裁标准,GJB 150A发布以来的很长一段时间内,许多使用人员还无法适应,对试验工作造成诸多困扰。为了指导研究人员摆脱菜单式标准的束缚,以GJB 150A为参考标准,根据某通信装备的寿命期剖面和寿命期环境剖面,论述了该装备低温试验的实施要点,对试验程序、试验顺序和试验条件的选择依据及结果给出了详细分析,提出了试验实施的设备与试件要求。     

毒性有机物BPA与普通小球藻的相互影响特性研究

考察了不同浓度双酚A(BPA)对普通小球藻(Chlorella vulgaris)生长特性的影响,以及普通小球藻生长过程对BPA的去除效能.研究表明,低浓度BPA(0~20 mg·L-1)对普通小球藻生长具有促进作用,而高浓度BPA(20~50 mg·L-1)对普通小球藻生长具有抑制作用,且抑制效应与BPA浓度呈正相关关系.低剂量BPA(<20 mg·L-1)对叶绿素含量并无明显的影响,高剂量BPA(>20 mg·L-1)造成叶绿素含量降低.在BPA初始浓度2~50 mg·L-1的范围内,普通小球藻对其都有一定的去除效能,单位普通小球藻对BPA去除速率与其初始浓度呈正相关关系.BPA投加量为50 mg·L-1时,BPA去除速率最大,且最大速率出现于延滞期与对数期之间.     

Effects of synthetic pyrethroids and methidation on activities of some digestive enzymes in carp (Cyprinus carpio L.)

Abstract

The effects of pyrethroid pesticides (deltamethrin, permethrin and cypermethrin) and an organophosphate ester (methidation) on the activities of carp trypsin, α‐chymotrypsin, carboxypeptidase A and lipase were studied. The enzymes were isolated from the gastrointestinal tract and the effects of the pesticides were investigated during incubation for 5 min. The activity of trypsin was influenced only slightly by the presence of deltamethrin and methidation, whereas permethrin and cypermethrin caused significant inhibition. The pyrethroid pesticides at lower concentrations resulted in a slight activation of α‐chymotrypsin. Methidation inhibited the α‐chymotrypsin activity by about 20%. These pesticides modified the lipase activity to a lesser extent; the highest inhibition was measured with cypermethrin. The carboxypeptidase A activity was inhibited by both pyrethroid pesticides and methidation. The results suggest that these pesticides might interact with the active conformation of the studied hydrolytic enzymes, resulting in changes in their activities.