松科植物对干旱胁迫的反应

水分亏缺是制约树木生长的重要环境因子，植物通过形态、生理以及分子水平来适应水分亏缺．渗透调节使植物在低水势下维持正常生理活动，是植物忍耐水分亏缺的重要生理机制．干旱胁迫下，植物形态结构变化有利于水分吸收和传导，从而提高水分利用效率；同时，生物量向根部的分配增加，叶面积/边材面积比发生变化，这种生物量分配转移提高了根和茎向叶片输水能力，从而防止气穴现象；干旱胁迫容易引起光能过剩，过剩的光能会对光合器官产生潜在的危害．依赖于叶黄素循环的热耗散是光保护的主要途径；同时酶促及非酶促系统也是防止光合器官破坏的重要途径；脱落酸作为一种激素逆境信号，活化了与抗旱诱导有关的基因．本文从形态变化、渗透调节、气穴现象、光合作用、水分利用效率、脱落酸以及分子机理等方面阐述了松科植物对干旱胁迫的响应，并对耐旱指标的筛选进行了讨论，干旱胁迫下，各耐旱机理相互制约，需要联合各个方面的因素来考虑整个植物对干旱的反应．参99。     

开拓有机高分子絮凝剂在炼厂污水处理中的应用

通过有机高分子絮凝剂在炼厂污水处理中的应用试验，表明有机高分子絮凝剂各方面性能均优于单一的无机盐絮凝剂。开拓有机高分子絮凝剂在炼厂污水处理中的应用，是当前提高污水外排综合合格率的一个重要手段。     

气相色谱法估算多环芳烃半数致死浓度

 用气相色谱相对比保留体积Vg（r）估算多环芳烃PAHs在鱼体内96h的半数致死浓度（LC₅₀）.测定了麦穗鱼对萘、联苯、β－甲基萘、2，3一二甲基萘、2，7一二甲基萘、苊、菲7种PAHs的LC₅₀，建立了6种不同极性色谱固定相上的LC₅₀与Vg（r）的一元回归方程和LC₅₀、Vg（r）、一阶分子连接性指数'Ｘ的二元回归方程，统计检验表明，两类回归方程总体显著相关，巨相关性不受固定相极性的影响用Vg（r）估算PAHs对水生生物LC₅₀是一种估算精度高，可操作性强的好方法．     

现代分子生物技术在废水菌群监测中的应用

荧光原位杂交、DNA指纹等现代分子生物技术在废水治理过程中得到了广泛的应用。对现代分子技术的分类及其在废水菌群监测中的应用进行了简要的论述,并通过各类技术间的比较,提出其潜在的问题及应用前景。     

不同分子量及离子度的CPAM对污泥脱水性能的影响研究

阳离子聚丙烯酰胺(CPAM)以其良好的絮凝效果被广泛用于改善市政污泥的脱水性能.然而,由于CPAM的分子量和离子度存在多样性,其促进市政污泥脱水的机理尚不明确.本研究通过测定CPAM调理后的污泥比阻、污泥上清液浊度、Zeta电位、胞外聚合物,对12组不同分子量和离子度的CPAM促进污泥脱水的机理进行研究.结果表明:CPAM能显著提高胶体絮凝能力,进而改善污泥的脱水性能;在CPAM的离子度或者分子量较低(离子度40%或分子量6×106)时,其絮凝机理主要表现为吸附架桥;随着离子度和分子量增加到50%和8×106时,CPAM的电中和作用显著增强,并与吸附架桥作用协同促进污泥的絮凝脱水;CPAM离子度的增加更能减少胞外聚合物中核酸含量,这有利于降低污泥亲水性能,从而促进其脱水.     

Toxic interaction mechanism of two fluoroquinolones with serum albumin by spectroscopic and computational methods

To evaluate the toxicity of two fluoroquinolones (FQs), ciprofloxacin (CPFX), and enrofloxacin (ENFX), at the protein level, their binding modes with bovine serum albumin (BSA) were characterized by multiple spectroscopic and molecular docking methods under simulated physiological conditions. On the basis of fluorescence spectra, we concluded that both FQs greatly quenched the fluorescence intensity of BSA, which was attributed to the formation of a moderately strong complex mainly through electrostatic interactions. Besides, CPFX posed more of an affinity threat than ENFX. The molecular docking methods further illustrated that both CPFX and ENFX could bind into the subdomain IIIA of BSA and interact with Arg 508 and Lys 437, the positively charged residues in protein. Furthermore, as shown by the synchronous fluorescence, UV-Visible absorption and circular dichroism data, both CPFX and ENFX could lead to the conformational and microenvironmental changes of BSA, which may affect its physiological function.     

Homology modeling of anti-parathion antibody and its interaction with organophosphorous pesticides and analogues

The mechanism of specific recognition in pesticide immunochemistry was investigated by computer-based strategy, and a rapid method for the identification of antibody specificity was developed. Based on the previously produced anti-parathion monoclonal antibody (mAb), the DNA sequence was analyzed by polymerase chain reaction (PCR). From the translated amino acid sequences, a three-dimensional structure of the antibody was constructed by homology modeling method, and then it was coordinated by 1 ns molecular dynamics under the explicit solvent condition. The stereochemical property and folding quality were further assessed by Procheck and Profile-3D. The self-compatibility score for the antibody model was 98.7, which was greater than the low score 46.2 and close to the top score 102.6. In addition, parathion and several structural analogues were docked to the constructed antibody structure. The docking results showed that the interaction energy (-40.54 kcal/mol) of antibody-parathion complex was the lowest among all the tested pesticides, which accounted for the high specificity of the antibody to parathion and perfectly matched with the experimental data. Moreover, three residues, Phe165, Asp107 and Thr100 were recognized as the most important residues for antibody reacting with parathion. The interaction energy negatively correlated with the antibody specificity.     

氯代苯类化合物对江水细菌的毒性及QSAR研究

采用细菌生长抑制实验,测定了18种氯苯类化合物对长江水中混合细菌的毒性,得到24 hIC₅₀值,-1gIC₅₀为3.65～4.32,其中,毒性最弱的是氯苯,毒性最强的是1,2,4-三氯苯.选用分子连接性指数法对毒性数据进行定量结构活性关系(QSAR)研究.结果表明,氯苯类化合物对江水细菌的毒性与苯环上取代基的种类、数目和位置有关,价分子连接性指数0XV和7X_CHV能够很好地描述氯苯类化合物对江水细菌的毒性.方程-1gIC₅₀=0.8390XV-25.3727X_CHV+0.802的稳健性很好,该模型的预测值与毒性实测值之间的相关系数达0.948.