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.     

3种填料A.ferrooxidans挂膜效果及对模拟酸性矿山废水中Fe2+生物矿化能力比较

氧化亚铁硫杆菌（A.ferrooxidans）介导的生物矿化方法可促使酸性矿山废水（Acid Mine Drainage,AMD）中Fe离子向次生铁矿物转变. 采用固定化的方式来提高A.ferrooxidans密度有助于强化Fe²⁺的生物矿化能力.选取流化床19孔填料、弹性填料、悬浮球填料作为挂膜对象, 通过多批次的连续培养来考察3种填料的A.ferrooxidans挂膜能力及稳定挂膜所需周期,继而比较3种挂膜填料对模拟AMD中Fe²⁺的生物矿化能力,并估算A.ferrooxidans有效生物量.结果表明,3种填料（5.00 g）的A.ferrooxidans挂膜能力依次为弹性填料（1.76 g）＞流化床19孔填料（0.90 g）＞悬浮球填料（0.78 g）（干重）,且挂膜启动至稳定状态至少需要4批次.X射线衍射分析（X-ray diffraction,XRD）表明,3种填料表面 含矿生物膜均为施氏矿物和黄钾铁矾的混合物.以游离态A.ferrooxidans的Fe²⁺氧化速率作为参比,估算出流化床19孔填料、弹性填料、悬浮球填料生物膜中A.ferrooxidans有效生物量依次为1.67×10⁸、8.52×10⁸、1.92×10⁸ cells·g^-1 （干基）.研究还发现,等同Fe²⁺生物氧化速率下, A.ferrooxidans挂膜填料比游离态A.ferrooxidans具有更强的AMD矿化驱动能力.     

A/O-MBBR工艺处理生活污水性能及菌群结构

采用设计规模为100m³/d的一体化缺/好氧-移动床生物膜反应器(A/O-MBBR)处理实际生活污水,通过265d的中试研究考察了该工艺在多因素扰动下的除碳和脱氮性能,并对不同运行阶段微生物群落结构的动态变化进行了研究.结果表明,一体化A/O-MBBR系统具有良好的COD去除效果和脱氮性能.当好氧池溶解氧(DO)浓度和进水碳氮比(COD/N)分别为2.5~3.5mg/L和(7.9±2.0)时,COD、NH₄⁺-N和TN去除率分别达到(93.3±5.4)%、(99.1±0.6)%和(67.9±10.5)%.Proteobacteria、Bacteroidetes和Chloroflexi在不同运行时期均有较高的相对丰度,保证了有机物的高效去除.A/O-MBBR系统脱氮功能菌在运行初期主要分布于活性污泥中,且相对丰度较低.长期运行后,生物膜与活性污泥中均同时检出大量硝化菌和反硝化菌.其中,相对丰度最高的硝化菌为Nitrospira,主要分布于生物膜上(19.48%~28.05%).反硝化菌则以Thauera、Terrimonas和Dokdonella等为主.     

污泥基生物炭提升活性污泥系统处理性能

对污泥基生物炭提升活性污泥系统处理性能进行探讨,将活性炭和污泥基生物炭分别投入A²O工艺厌氧池活性污泥,发现其对COD削减率最高分别为72.9%和41.1%,均能有效削减,生物炭对TN削减率最高为74.1%,优于活性炭.表征显示污泥基生物炭上更易附着活性污泥且比表面积更大.在A²O小试厌氧池中以"1次/污泥龄"为频率投加活性炭、污泥基生物炭和脱脂污泥基生物炭,结果发现:投加污泥基生物炭对COD、TN、TP的削减均优于活性炭,投加脱脂污泥基生物炭对COD、TN的削减与投加活性炭相当,对TP平均削减率高达85.6%,优于活性炭,表明生物炭处理(BT)工艺比粉末活性炭处理(PACT)工艺处理生活污水能力更强,脱脂污泥基生物炭作为污泥脂质提取后的副产品更经济.