合成有机物结构-生物降解性关系的研究

本文综述了合成有机物生物降解性的研究方法.以及定性结构-生物降解性关系(SBR).重点综述了芳香类化合物的结构与生物降解性的关系.研究这一关系有助于有毒化学品生物降解性的预测.     

湖泊水环境保护功能区划分

在浓度场基础上，利用总磷、总氮和ＣＯＤ三项指标的综合指数法，结合管理部门提供的资料，划分了滇不不环境保护功能区，给出了划分指标值及功能区划分图。     

汞矿地区人发中甲基汞的气相色谱测定

本文采用气相色谱法测定人发中甲基汞，对人发的酸度，浸取时间，人发与酸液的比例，以及无机汞存在的影响作了测定和选择，方法的平均回收率９６．６％，精确度２．８％，方法可靠性用氢化物原子荧光法核对，结果一致，并对我国某矿区职工，儿童及产妇发样分析结果作了讨论。     

染料生物吸附影响因素与解吸条件研究

用筛选出的一株丝状真菌(GX2)对活性、酸性、碱性和直接染料进行吸附及解吸的试验结果表明，该菌株对活性、酸性和直接染料有较高的吸附率，但碱性染料难被吸附；在多种有机溶剂中，丙酮是较好的解吸剂，碱性介质有利于染料的解吸；对菌体进行破碎及在解吸过程中加以搅拌有利于解吸过程的进行。     

内蒙古自治区锡林郭勒盟地震的启示

2004年3月24日9时33分在内蒙古自治区东乌珠穆沁旗与西乌珠穆沁旗间(北纬45.4°,东经118.2°)发生5.9级地震。北京、辽宁朝阳、吉林白城、河北承德地区有感。自治区地震局迅速确定“三要素”,召集紧急会议确定考察队与局留守队,并迅速向灾区了解灾情,向自治区政府报告。同时启动破坏     

The fungicide difenoconazole alters mRNA expression levels of human CYP3A4 in HepG2 cells

The fungicide difenoconazole has been frequently detected in agricultural products, soils and surface waters, causing increasingly public concern due to toxicological properties. Although systemic triazole fungicides can inhibit the enzymatic activity of many CYP450 isozymes, how difenoconazole affects the human CYP3A4 still remains largely unknown. We thus investigated the effect of difenoconazole on normal mRNA expression and protein expression of human CYP3A4 by real-time quantitative PCR and western blot, respectively. Results show that the exposure to difenoconazole from 0.01 to 0.5 μM for 24 h down-regulates mRNA expression levels of human CYP3A4 in HepG2 cells. We also found that difenoconazole could inhibit the enzymatic activity of human CYP3A4 in a concentration-dependent mode. The IC₅₀ of difenoconazole for inhibition of CYP3A4 activity is 0.41 µM, showing a stronger inhibitor in comparison with ketoconazole. Overall, our findings indicate the potential risk of difenoconazole for the disruption of human CYP3A4.     

Effect of F,Cl, Br and I substitution on the BphB enzyme for the degradation of halogenated biphenyls,revealed by quantum and molecular mechanics

Halogenated biphenyls are worldwide persistent pollutants of great environmental concern. In particular, polychlorinated biphenyls and polybrominated biphenyls have been globally used for industrial purposes until they were found highly toxic, mutagenic and carcinogenic to humans. Therefore, ecological strategies to remove halogenated biphenyls, such as enzyme-catalyzed degradation, are needed. Here, we studied the effect of substitution of F, Cl, Br or I at the 4,4′-positions of 2,3-dihydro-2,3-dihydroxybiphenyl-2,3-dehydrogenase (BphB) on the degradation of halogenated biphenyls by quantum and molecular mechanics. Results show that Boltzmann-weighted average degradation barriers of substituted BphB are all lower than the unsubstituted biphenyl, except for chlorinated biphenyl. The roles of residues nearby the active site, e.g., isoleucine89, asparagine115, serine142, asparagine143, proline184, methionine187 and threonine189, were also investigated.

     

乙草胺对蛋白核小球藻的毒性效应研究

乙草胺是我国使用量最大的除草剂之一,在水体中广泛存在。已有研究证明,乙草胺对人类、老鼠和鱼类具有毒害效应,而关于其对浮游植物影响的研究较少。以蛋白核小球藻(Chlorella pyrenoidosa)为模型,使用1～10 000μg·L~(-1)的乙草胺对其进行7 d的暴露实验,考察小球藻生长性能、叶绿素含量、光合作用产氧量以及光合作用相关基因(pbsA、rbcL和rbcS)表达的变化。结果表明,较低浓度的乙草胺可刺激蛋白核小球藻生长,而较高浓度乙草胺则会抑制其生长;并且乙草胺会通过影响小球藻叶绿素的含量而影响光合作用产氧量;小球藻光合作用相关基因pbsA、rbcL和rbcS表达大多显著上升,这可能是对乙草胺胁迫响应的反馈调节。研究表明,乙草胺会对蛋白核小球藻的生长及光合作用产生影响。     

底泥中酸性挥发硫及同步浸提金属的测定

同步浸提金属与酸性挥发硫的比值在判断底泥重金属生物毒性方面有重要意义．描述了一套测定底泥酸性挥发硫和同步浸提金属的仪器装置和分析程序．从气体流速、反应时间、酸浓度、硫含量等方面研究了酸性挥发硫测定的最适反应条件．在此条件下酸性挥发硫的测定回收率可达９０％以上．该方法的最低检出限为００２μｍｏｌ／ｇ（干泥）．     

Analysis of microcystins in cyanobacteria blooms and surface water samples from Meiliang Bay,Taihu Lake,China

Taihu Lake is the third largest freshwater lake in China. In recent years, the water pollution of cyanobacteria blooms has become a severe problem in this area. Microcystins (MCs) are an important group of toxic compounds mainly produced by some cyanobacteria species and have both acute and chronic hepatotoxic effects on animals and humans. This paper presents the first data on the identification and detection of MCs in both natural occurring cyanobacteria blooms and surface water samples (0-0.5 m), collected from Meiliang Bay, Taihu Lake, China. A conventional method for extraction and isolation of MCs from cyanobacteria blooms was applied. High-performance liquid chromatography (HPLC) analysis showed that the main toxic component in the cyanobacteria materials was MC-LR. The monoclonal antibody (mAb) against MC-LR produced by hybridoma technique was employed for direct competitive ELISA to detect the concentrations of MCs in bloom and water samples collected in 2001. The results not only revealed the presence of MCs but also temporal variations of MCs levels of three sampling stations in Meiliang Bay in 1 year. It is obvious that the MC contents were relatively higher during warm months and related with the status of eutrophication. Our study indicates the threat associated with MCs in water body of Taihu Lake. To prevent the MCs potential hazard on public health in this area, some necessary measures of monitoring and control of growth of cyanobacteria are urgently needed.