用环境毒物对草鱼组织ATPase的影响作为生态毒理学指标的初步研究

不同季节捕获的草鱼在实验室(16±4℃)驯化3—7天,其鳃ATPase活力在显著性水平为0.05时,不同批鱼无显著差异。离体实验条件下,汞、三氯联苯、直链烷基苯磺酸钠对草鱼组织ATPase的半抑制浓度分别为1.8ppM(肾),1.84ppM(鳃),3.9ppM(鳃);Hg~(2+)对肾的作用大于对鳃的作用。草鱼组织ATPase可作为一项指标用于毒理学研究。

聚合物载体缩硫醛大环螯合剂的合成和选择络合汞的性能以及做为高分子汞解毒促排药物的动物实验

在我国某些地区，汞的污染已达到十分严重的程度。如，第二松花江吉林市下游江段，江水总汞含量和鱼体含汞量已能和日本严重汞污染的水俣湾相比。在化学工业，仪表工业中，汞中毒列为严重性占第二位的职业病。因此，汞的污染防治已是急待解决的问题。各种含硫螯合剂可应用于含汞污水处理及汞中毒的治疗。Nyssen等1976年合成了一种缩聚型的缩硫醛大环螯合树脂，作者希望它能成为汞中毒的口服解毒药物。这种产物对Hg~(++)和CH_3Hg~+表现了极强的选择络合性能。但是由于其交联结构不利于Hg~(++)深入树脂内部，因此络合容量太低，仅为2毫克Hg~(++)/克。为了提高其络合能力并进而得到一种水溶性产物，我们合成了二种新的高分子缩硫醛大环螯合剂；其一，以聚苯乙烯为载体的缩硫醛大环螯合剂（简写为PS-S）。其二，以右旋糖苷为载体的缩硫醛大环螯合剂（简写为D-S）。前者做为螯合树脂表现了对Hg~(++)极强的选择络合能力，并且络合容量比缩聚型产物高十倍以上（达30-60毫克Hg~(++)/克）。后者经动物实验证明是一种无毒而有效的高分子汞解毒药。（一）PS-S的合成和络合性能1）醛基的引入采用了不同交联度的凝胶型聚苯乙烯（PS）树脂及不同孔径和表面的大孔型PS树脂做为骨架材料，并采用了二种不同的方法在PS上联结醛基。2）PS-S的合成采用了一系列巯基化合物与PS-CHO反应合成PS-S。例如，用乙二醇二巯基乙酸酯与PS-CHO反应，其它采用的巯基化合物还有：丁二醇二巯基乙酸酯、季戊四醇四巯基乙酸酯、乙硫醇、巯基乙酸、巯基乙酸乙酯等。同一骨架材料的上述各产物的静态Hg~(++)络合容量基本相同，可是含硫环的大小对络合容量影响不大。3）缩硫醛化产物模型化合物的研究合成了几种小分子缩硫醛化产物，对它们进行了MS、NMR谱分析，从以上三种不同类型的缩硫醛化产物本身及其对Hg~(++)作用物的稳定性比较，以第二类大环型产物稳定性最好。4）不同骨架结构的PS-S络合性能比较对不同交联度的凝胶型PS树脂为骨架的PS-S树脂，及不同孔经和比表面积的大孔型PS树脂为骨架的PS-S树脂，分别测定了对Hg~(++)的络合容量，结果表明：大孔型PS-S树脂络合容量最高。当其孔径在100-1000埃，比表面积100米~2/克时，静态络合容量可达65毫克Hg~(++)/克。5）大孔PS-S树脂络合性能的研究①研究了不同测定方法下（静态法、动态法、饱和法），不同测定条件（如树脂用量、Hg~(++)溶液浓度等）对产物络合容量测定的影响。在PS-S装柱反复络合洗脱十次后，树脂络合容量不下降。②不同PH测定PS-S络合容量表明：中性条件下对Hg~(++)络合容量较高。某些有机溶剂（如乙醇、二氧六环）加入Hg~(++)水溶液有利于络合容量的提高。而某些有机溶剂（如丙酮、乙酸）的添加却降低了树脂络合容量。③大孔PS-S树脂对不同金属离子(Pb~(++)、Co~(++)、Cd~(++)、Ca~(++)、Zn~(++))络合容量的测定表明：大孔PS-S树脂对Hg~(++)的络合容量比上述其它金属离子高几十倍到近千倍。（二）D-S的合成与性能研究了介质、温度、时间、反应物用量等条件对反应结果的影响，反应所用Dextran分子量31600，生成的D-CHO含醛基量0.66毫克当量/克。生成的D-S含硫量3.5～6%，分子量约3600。（三）PS-S和D-S对汞中毒巯基酶的解毒实验生物体汞中毒的一个重要毒理是汞使巯基酶中毒，我们采用了PS-S和D-S来对汞中毒的巯基酶-脲酶解毒，使失活的脲酶重新恢复活力，模拟药物在生物体内的解毒过程。实验表明：PS-S和D-S的解毒能力比相同重量的离子交换树脂、巯基树脂、巯基棉等都要强。而且很少量的PS-S和D-S就能使脲酶100%的恢复活力。不同用量的PS-S和D-S使汞中毒脉酶恢复活力的试验显示了良好的线性关系，尤其是D-S，它几乎等当量地（每二个硫原子络合一个汞原子）使汞中毒脲酶恢复活力。（四）D-S的汞解毒及代谢促排过程的同位素示踪试验1）当给小白鼠静脉注射极限注射量（达1毫升/只鼠）的6%D-S水溶液时未发生受试动物的死亡，即LD_(50) > 4000毫克/公斤体重，说明D-S是无毒的。同时病理镜检表明动物肝肾此时无异常。2）分别对10只小白鼠静注致死量的Hg~(++)，对其中一组注射D-S（0.2毫升/只）一次，结果3小时后对照组动物全部死亡时，给药组尚存活6只。D-S表面了对受试动物良好的保护作用。病理镜检表明D-S使肾脏的汞中毒病变有所缓解。3）用同位素~(125)I标记D-S，研究了口服，静注D-S在小白鼠体内的代谢情况。试验得到了D-S经静注，口服二种途径在小白鼠体内血、肝、肾、脾等主要脏器中的经时代谢曲线。六小时后D-S大部分代谢出体外，12天后全部代谢出体外。并进而得到了二种不同给药方式的药物代谢动力学方程。D-S口服为：C_血=0.1 (e~(-0.00183t)-e~(-0.01t))符合于一级吸收过程的单室模型 D-S静注为：C_血=0.384 e~(-0.645t) + 0.074 e~(-0.08t) + 0.042~(-0.00464t)符合于快速静注下的三室模型。4）采用~(203)Hg做了D-S口服、静注给药时对Hg~(++)的促排作用的实验，得到了二种给药方式下Hg~(++) 在小白鼠血、肝、肾、脑及全身的促排代谢经时曲线。实验表明D-S对汞有明显促排作用，其中口报组效果更好。D-S促排与代谢同位素示踪试验数据之间表现了有趣的相关性，有助于我们解释D-S对汞促排的机制。动物实验表明：D-S可能成为一种临床使用的副作用小的汞中毒解毒促排新药。

巯基化合物在分析化学中的应用及其机理研究

本文利用活性碳吸附蔗糖后再与巯基乙酸反应合成了一种新的分离吸附剂-巯基活性碳吸附剂，详细研究了其各种制备条件。实验表明，用这种方法合成的吸附剂是一种非常好的固体吸附剂，不仅能定量吸附各种重金属离子，而且具有很好的吸附脱附特性，其饱和吸附量是目前广泛应用的巯基绵的3～20倍。既克服了因巯基含量高对重金属离子难以洗脱的缺点，又大大提高了分离富集效率。探讨了巯基活性碳吸附剂中吸附因素对吸附能力的贡献，其中活性碳作用占17.3%，蔗糠作用占19.2%，巯基化后引入的吸附作用占63.5%。此三方面相互渗透，相互补充，相互加强，共同完成对重金属子离子的吸附作用。本文还从热力学和动力学两个方面研究了吸附剂对重金属离子的吸附机理。结果表明其吸附过程以化学吸附为主。外表面、内表面吸附率对Cu~(2+)分别为19%；81%；对Pb~(2+)分别为6%，94%，对Zn~(2+)分别为17%和83%，而吸附Cd~(2+)完全由内扩散所控制。并且发现其吸附Cu~(2+)的同时，还将其还原成Cu~o。从静态和动态两个方面探讨了溶液酸度、温度、吸附时间、Ca~(2+)、Na~+等干扰离子，以及重金属离子浓度等对新型分离吸附剂吸附能力的影响。结果表明，此吸附剂具有很高的吸附能力和很好的稳定性，可以应用于实际样品的测定。通过用表面有机合成法将巯基键合在玻碳电极的表面，得到了巯基修饰电极（MAMGCE），此种修饰电极与未加修饰的玻碳电极（GCE）相比，不仅可化学吸附重金属离子如汞离子，而且灵敏度提高了近10倍。当富集时间为3分钟时，其线性范围为1X_(10~(-8))mol/L～1X_(10~(-9))mol/L,相对标准偏差为7.7%。采用电子能谱等方法对MAMGCE电化学性质、电极反应机理进行了探讨，结果表明MAMGCE与Hg~(2+)的反应的产物在氧化及还原状态都存在弱吸附。通过将巯基乙酸作为一种支持电解质将巯基固定在导电聚吡咯薄膜电极上，制得巯基-聚吡咯薄膜修饰电极，该修饰电极保持了巯基的螯合性能，并具有良好的稳定性。此种修饰电极对水溶液中的重金属离子具有很好的吸附作用，其灵敏度与未修饰玻碳电极相比，测汞离子时电沉积提高了三倍，化学吸附时提高了近5倍。对其吸附机理进行的初步探讨证明其对汞离子的吸附为不可逆的产物弱吸附。本文研究了聚苯胺薄膜化学修饰电极对巯基化合物氧化还原的促进作用，系统地探讨了不同聚合介质、酸度等对PAn薄膜化学修饰电极对巯基乙醇促进作用的影响。采用扫描电镜、电子能谱、交流阻抗及拉曼光谱等各种检测手段对这种促进作用进行了探讨，结果表明这种促进作用是对巯基乙醇在PAn薄膜表面的氧化还原过程的一种加强，而这种加强作用是通过-SH与PAn中的N以质子形式加成的。

汞-豆磺隆，呋喃丹污染土壤的酶特征研究

采用模拟方法，研究了Hg、豆磺隆和呋喃丹对不同肥力草甸棕壤和黑土转化酶、脲酶、中性磷酸酶活性的影响及汞和2种农药之间对土壤酶活性的交互作用，并对不同温度条件下，汞、豆磺隆对土壤脲酶动力学参数的影响进行了研究，为建立重金属、农药污染土壤酶监测指标体系和土壤污染酶修复工作提供理论参考。 试验结果表明，几种酶对土壤汞污染的敏感性顺序为脲酶 > 转化酶 > 中性磷酸酶，有机质含量高的土壤对汞抑制土壤酶的效应缓冲能力普遍较强，HgCl2浓度与脲酶和转化酶活性之间的关系均可用对数方程均可很好的描述，由于脲酶对汞的敏感性较强，可在一定程度上表征汞的污染程度，在建立土壤汞污染酶监测方法体系的领域，具有一定的研究潜力；而2种农药对3种土壤酶活性的影响较小，规律性较差，总体来说，豆磺隆对土壤脲酶有激活作用，对转化酶和土壤中性磷酸酶活性表现出抑制作用；呋喃丹对3种酶均有微弱的激活作用。 汞和豆磺隆或呋喃丹之间对土壤转化酶、脲酶、中性磷酸酶多数情况下均存在不同程度的交互作用，既有降低两种污染物毒性的拮抗作用，也有增强毒性的协同作用，因土壤类型、土壤肥力、污染物浓度和酶种类不同而存在差异。 除个别土样外，Hg浓度与脲酶动力学参数Km和Vmax和Vmax /Km值之间均呈显著(P < 0.05)或极显著(P < 0.01)负相关，这一现象符合典型的反竞争性抑制类型；豆磺隆对脲酶的激活效应很可能是由于其促进酶促反应初速度的提高引起的；Hg、豆磺隆同时添加对脲酶动力学参数Km、Vmax和Vmax /Km值的影响与单一添加Hg条件下相似，但由于豆磺隆的加入使规律性趋于复杂。 本试验温度范围内，对于汞污染，土壤对脲酶的保护能力随温度升高而有所下降；而对于豆磺隆单一污染、汞和豆磺隆复合污染污染，污染物对脲酶动力学参数的影响与温度之间没有显著关系。

不同放牧强度下高山草甸生态系统碳氮分布格局和循环过程研究

本研究针对川西北高山草甸缺乏科学管理，过度放牧导致草场退化，并由此引发的一系列生态环境问题，选取红原县瓦切乡1996 年草地承包后形成的四个放牧强度草场，即不放牧、轻度（1.2 头牦牛hm-1）、中度（2.0 头牦牛hm-1）和重度放牧（2.9 头牦牛hm-1），作为研究对象，研究了不同放牧强度对草地植物-土壤系统中碳、氮这两个最基本物质的分布格局和循环过程的影响，并探讨了放牧干扰下高山草甸生态系统的管理。 1．放牧对草地植物群落物种组成，尤其是优势种，产生了明显的影响。不放牧、轻度、中度和重度放牧草地群落物种数分别为22，23，26，20 种，群落盖度分别是不放牧96.2%＞中度93.6%＞轻度89.7%＞重度73.6%。随放牧强度的增加， 原植物群落中的优势种垂穗鹅冠草（ Roegneria nutans ）、发草（Deschampsia caespitosa）和垂穗披碱草（Elymus nutans）等禾草逐渐被莎草科的川嵩草（Kobresia setchwanensis）和高山嵩草（Kobresia pygmaea）所取代成为优势种。同时，随放牧强度的增加，高原毛茛（Ranunculus brotherusii）、狼毒（Stellera chamaejasme）、鹅绒委陵菜（Potentilla anserina）和车前（Plantagodepressa）等杂类草的数量也随之增加。 2．生长季6～9 月份，草地植物地上和地下生物量（0～30cm）都是从6 月份开始增长，8 月份达到最高值，9 月份开始下降。每个月份，通常地上生物量以不放牧为最高，重度放牧总是显著小于不放牧；地下生物量随放牧强度的增加表现为增加的趋势，通常重度和中度放牧显著高于不放牧和轻度放牧草地。不放牧、轻度、中度和重度放牧草地6～9 月份4 个月的植物总生物量平均值分别是1543、1622、2295 和2449 g m-2，但随放牧强度的增加越来越来多的生物量被分配到了地下部分，地下生物量占总生物量比例的大小顺序分别是重度88%＞中度82%＞轻度76%＞不放牧69%。生物量这种变化主要是由于放牧使得群落优势种发生改变而引起的，其分配比例的变化体现了草地植物对放牧干扰的适应策略。 3．植物碳氮贮量的季节变化类似与生物量的变化。每个月份，不同放牧强度间植物地上碳氮的贮量有所不同，一般重度放牧会显著减少植物地上碳氮贮量。植物根系(0～30cm)碳氮贮量随放牧强度的增加表现为增加的趋势，通常重度和中度放牧显著高于不放牧和轻度放牧草地。不放牧、轻度、中度和重度放牧草地6～9 月份4 个月的植物总碳平均值分别是547、586、847 和909 g m-2，根系碳贮量占植物总碳的比例大小顺序分别是重度88%＞中度82%＞轻度76%＞不放牧69%；放牧、轻度、中度和重度放牧草地6～9 月份4 个月的植物总氮平均值分别是17、17、23 和26 g m-2，根系氮贮量占植物总氮的比例大小顺序分别是重度79%＞轻度71%＞中度70%＞不放牧65%。 4. 土壤有机碳贮量（0～30cm）的季节变化表现为7 月份略有下降，8 月开始增加，9 月份达到的最大值。土壤氮贮量的季节变化表现为随季节的推移逐渐增加的趋势。增加的放牧强度不同程度的增加土壤有机碳氮的贮量。不放牧、轻度、中度和重度放牧6～9 月份4 个月的土壤有机碳贮量的平均值分别是9.72、10.36、10.62 和11.74 kg m-2，土壤氮贮量分别为1.45、1.56、1.66 和1.83 kg m-2。土壤中有机碳（氮）的贮量都占到了植物-土壤系统有机碳（氮）的90%以上，但不同放牧强度之间的差异不明显。 5. 土壤氮的总硝化和反硝化，温室气体N2O 和CO2 的释放率的季节变化表现为从6 月份开始增加，7 月份达到最大值，8 月份开始下降，9 月份降为最小值。增加的放牧强度趋向于增加土壤氮的总硝化和反硝化作用，温室气体N2O和CO2 的释放率，通常情况下，中度放牧和重度放牧显著地加强了这些过程。 6．垂穗鹅冠草（Roegneria nutans）和川嵩草（Kobresia setchwanensis）凋落物在不同放牧强度下经过1 年的分解，两种凋落物的失重率及其碳氮的损失率3都随放牧增加表现为增加的趋势。在同一放牧强度下，川嵩草凋落物的失重率和碳氮的损失率都高于垂穗鹅冠草凋落物。 7. 尽管重度放牧显著增加了土壤碳氮的贮量，但同时也显著降低了植被群落盖度，降低了植物地上生物量，因此，久而久之会减少植物向土壤中的碳氮归还率；与不放牧和轻度放牧相比，重度放牧又显著增加了土壤CO2 和NO2 的排放量，这是草地生态系统碳氮损失的重要途径。由此可见，对于这些地处青藏高原的非常脆弱的高山草甸生态系统，长期重度放牧不仅导致植物生产力降低，而且将导致草地生态系统退化，甚至造成土壤中碳氮含量减少。 Long-term overgrazing has resulted in considerable deterioration in alpine meadowof the northwest Sichan Province. In order to explore management strategies for thesustainability of these alpine meadows, we selected four grasslands with differentgrazing intensity (no grazing-NG: 0, light grazing-LG: 1.2, moderate grazing-MG: 2.0,and heavy grazing-HG: 2.9 yaks ha-1) to evaluate carbon, nitrogen pools and cyclingprocesses within the plant-soil system in Waqie Village, Hongyuan County, Sichuan Province. 1. Grazing obviously changed the plant species composition, especially ondominant plant species. Total number of species is 22, 23, 26, and 20 for NG, LG, MGand HG, respectively. Vegetation coverage under different grazing intensity ranked inthe order of 96.2% for HG＞93.6% for MG＞89.7% for LG＞73.6% for NG. Thedominator of HG community shifted from grasses-Roegneria nutans andDeschampsia caespitosa dominated in the NG and LG sites into sedges-Kobresiapygmaea and K. setchwanensis. At the same time, with the increase of grazingintensity, the numbers of forbs, such as Ranunculus brotherusii, Stellera chamaejasme,Potentilla anserine and Plantago depressa, increased with grazing intensity. 2. Over the growing season, aboveground and belowground biomass showed a 5single peak pattern with the highest biomass in August. For each month, abovegroundbiomass usually was the highest in the NG site and lowest in the HG site.Belowground biomass showed a trend of increase as grazing intensity increased and itwas significantly higher in the HG and MG site than in the NG and LG sites. Totalplant biomass averaged over the growing season is 1543, 1622, 2295 and 2449 g m-2for NG, LG, MG and HG, respectively. The proportion of biomass to total plantbiomass for NG, LG, MG and HG is 88%, 82%, 76% and 69%, respectively. Higherallocation ratio for is an adaptive response of plant to grazing. 3. Carbon and nitrogen storage in plant components followed the similar seasonalpatterns as their biomass under different grazing intensities. Generally, heavy grazingsignificantly decreases aboveground biomass carbon and nitrogen compared to nograzing. Carbon and nitrogen storage in root tended to increase as grazing increasedand they are significantly higher in the HG and MG sites compared to the LG and NGsite. Total Carbon storage in plant system averaged over the growing season is 547,586, 847 and 909 g m-2 for NG, LG, MG and HG, respectively, while 17, 17, 23 and 26g m-2 for nitrogen. The proportion of carbon storage in root to total plant carbon forNG, LG, MG and HG is 88%, 82%, 76%, 69%, respectively, while 65%, 71%, 70%and 79% for nitrogen. 4. Carbon storage in soil (0-30cm) decreased slightly in July, then increased inAugust and peaked in September. Nitrogen storage in soil tended to increase withseason and grazing intensity. Total Carbon storage in soil averaged over the growingseason is 9.72, 10.36, 10.62 and11.74 kg m-2 for NG, LG, MG and HG, respectively,while 1.45, 1.56, 1.66 and 1.83 for nitrogen. The proportion of carbon (nitrogen)storage in soil to plant-soil system carbon (nitrogen) storage for NG, LG, MG and HGis more than 90%, which is not markedly different among different grazing intensities. 5. Gross nitrification, denitrification, CO2 and N2O flux rates in soil increasedfrom June to July and then declined until September, all of which tended to increasewith the increase of grazing intensity. Generally, heavy and moderate grazing intensitysignificantly enhanced these process compared to no and light grazing intensity. 6. After decomposing in situ for a year, relative weight, carbon and nitrogen loss in the litter of Roegneria nutans and Kobresia setchwanensis tended to increase asgrazing intensity increased. Under the same grazing intensity, relative weight, carbonand nitrogen loss in the litter of Kobresia setchwanensis were higher than these in thelitter of Roegneria nutans. 7. Although heavy grazing intensity resulted in higher levels of carbon andnitrogen in plant and soil, it decreased vegetation coverage and aboveground biomass,which are undesirable for livestock production and sustainable grassland development.What is more, heavy grazing could also introduce potential carbon and nitrogen lossvia increasing CO2 and N2O emission into the atmosphere. Grazing at moderateintensity resulted in a plant community dominated by forage grasses with highaboveground biomass productivity and N content. The alpine meadow ecosystems inTibetan Plateau are very fragile and evolve under increasing grazing intensity by largeherbivores; therefore, deterioration of the plant-soil system, and possible declines insoil C and N, are potential without proper management in the future.

汞对土壤酶活性的影响

利用室内模拟方法,研究了重金属Hg对不同土样脲酶、转化酶和中性磷酸酶活性的影响.结果表明,Hg可显著地抑制土壤脲酶和转化酶的活性,但不同土样Hg对两种酶活性的抑制程度有很大差别.HgCl2浓度与两种酶活性之间的关系均可用对数方程很好地描述(P<0.05).4个土样的脲酶ED50(生态剂量)分别为87.99、5.47、24.05和19.88mg.kg-1;转化酶的ED50分别为76.68、727.49、236.52和316.59mg.kg-1.脲酶对Hg污染比转化酶敏感;有机质对土壤酶活性有一定的保护作用.除连续2年施用大量有机肥的草甸棕壤土样中Hg对中性磷酸酶有显著的激活作用外(P<0.05),其它土样无显著变化,表明中性磷酸酶活性对Hg污染反应不敏感.

汞和两种农药复合污染对土壤转化酶活性的影响

通过模拟方法研究了豆磺隆,呋喃丹2种农药与重金属汞(Hg)单一及复合污染对草甸棕壤和黑土4个土壤转化酶活性的影响.结果显示,在试验浓度范围内,土壤添加豆磺隆和呋喃丹后,转化酶变化幅度分别为-12%~7%和-6%~7%,表明2种农药对土壤转化酶的毒性较小;Hg对转化酶最大抑制率为22%~35%,二者之间呈显著的对数负相关关系,表明Hg对转化酶的毒性较大,转化酶在一定程度上可作为Hg污染的监测指标,通过对数方程计算出4个土样的生态剂量(ED50)分别为76.68,727.49,236.52,316.59mg/kg;Hg和2种农药之间普遍存在交互作用,豆磺隆与Hg复合污染引起土壤转化酶最大净变化量(?I)为对照的-12%~15%,呋喃丹和Hg为-25%~-6%,有机质对复合污染产生的毒性有明显的缓冲作用.

新型分离富集剂对重金属离子吸附能力的研究

本文从静态和动态两个方面探讨了各种实验条件对新型分离富集剂吸附能力的影响。结果表明:在静态条件下,Cd~(2+)和Zn~(2+)的吸附平衡时间为1h,Pb~(2+)和Cu~(2+)为1.5h;富集剂对上述几种离子的吸附速度的顺序是:Pb~(2+)>Cu~(2+)>Zn~(2+)>Cd~(2+);当[Mg~(2+)]<200mg/L,[Ca~(2+)<400mg/L,[K~+]<350mg/L时,此三种金属离子不会干扰对Cu~(2+)的吸附。对于动态吸附,当吸附剂用量为0.1g(对Hg~(2+)),或0.15g(对Cu~(2+)),pH为0.3—8(对Hg~(2+)),3～8(对Cu~(2+))及流速>7mL/min(对Hg~(2+)),或≤10mL/min(对Cu~(2+))时,本富集剂可完全吸附上述两种物质。另外,此富集剂的饱和吸附量为巯基棉的3—20倍,具有很高的吸附能力和很好的稳定性。

Purification and characterization of the chitosanase from Aeromonas sp HG08

In this work, the characterization of a chitosanase-producing bacterium isolated from soil was reported and this strain was grouped under the genus Aeromonas by virtue of its morphological, physiological properties and 16S rDNA gene sequences. It is the first report that the genus Aeromonas could produce chitosanase. Aeromonas sp. HG08 could secrete the chitosanase ( named AsChi) with molecular weight of 70 kDa. The optimum pH and temperature of AsChi was 6.0 and 55 degrees C, respectively. The activity of AsChi was markedly enhanced by Mn2+ and inhibited by Fe3+, Cu2+, Ag+ and Hg2+; additionally, the activity of AsChi was increased with the degree of deacetylation ( DDA) of chitosan. Through viscosimetric assay, AsChi probably hydrolyzed chitosan in an endo-type fashion.

Purification and characterization of agarases from a marine bacterium Vibrio sp. F-6

Marine bacterium Vibrio sp. F-6, utilizing agarose as a carbon source to produce agarases, was isolated from seawater samples taken from Qingdao, China. Two agarases (AG-a and AG-b) were purified to a homogeneity from the cultural supernatant of Vibrio sp. F-6 through ammonium sulfate precipitation, Q-Sepharose FF chromatography, and Sephacryl S-100 gel filtration. Molecular weights of agarases were estimated to be 54.0 kDa (AG-a) and 34.5 kDa (AG-b) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH values for AG-a and AG-b were about 7.0 and 9.0, respectively. AG-a was stable in the pH range of 4.0-9.0 and AG-b was stable in the pH range of 4.0-10.0. The optimum temperatures of AG-a and AG-b were 40 and 55 degrees C, respectively. AG-a was stable at temperature below 50 degrees C. AG-b was stable at temperature below 60 degrees C. Zn2+, Mg2+ or Ca2+ increased AG-a activity, while Mn2+, Cu2+ or Ca2+ increased AG-b activity. However, Ag+, Hg2+, Fe3+, EDTA and SDS inhibited AG-a and AG-b activities. The main hydrolysates of agarose by AG-a were neoagarotetraose and neoagarohexaose. The main hydrolysates of agarose by AG-b were neoagarooctaose and neoagarohexaose. When the mixture of AG-a and AG-b were used, agarose was mainly degraded into neoagarobiose.

氢化物原子荧光法测定药用动物角中的微量砷和汞

以HNO_3-HClO_4回流消解样品，采用氢化物发生无色散原子荧光光谱法测定青藏高原药用动物角中的微量元素砷和汞。方法简便、快速、灵敏、准确。在实验条件下，26种共存元素其含量低于允许存在量，对测定无影响。检出限As 1.5 ng·mL~(-1)，Hg 0.80 ng·mL~(-1)；RSD (n = 11) As 1.2%～2.3%，Hg 2.5%～4.7%；标准回收率As 98.9%～103.8%，Hg 95.4%～105.0%。

红枫湖水体中活性汞和溶解气态汞的分布特征及其控制因素

基于二次金汞齐结合冷原子荧光测定法对红枫湖活性汞（RHg）和溶解气态汞（DGM）的时空分布特征及其控制因素进行了研究.红枫湖溶解气态汞含量（ρ（DGM））为0.024-0.110 ng/L,随着水深的增加ρ（DGM）降低,且夏季高,冬季低,这种分布特征表明光在原子态汞的形成中起着重要的作用.红枫湖ρ（DGM）除受光强影响外,还受到春季后五大量生长的藻类影响,但与溶解性有机碳含量（ρ（DOC））及温度的相关性不大.活性汞含量（ρ（RHg））为0.14-2.70 ng/L,其主要受Hg^2＋的光致还原过程,Hg^2＋的甲基化过程以及人为源的释放等因素的控制

Acid catalyzed synthesis of ordered bifunctionalized mesoporous organosilicas with large pore

Thiol-functionalized mesoporous ethane-silicas with large pore were synthesized by co-condensation of 1,2-bis(trimethoxy-sily)ethane (BTME) with 3-mercaptopropyltrimethoxysilane (MPTMS) using nonionic oligomeric polymer C1H (OCH(2)-CH(2))(10)OH (Brij-76) or poly(alkylene oxide) block copolymer (P123) as surfactant in acidic medium. The results of powder X-ray diffraction (XRD), nitrogen gas adsorption, and transmission electron microscopy (TEM) show that the resultant materials have well-ordered hexagonal mesoscopic structure with uniform pore size distributions. (29)Si MAS NNR, (13)C CP-MAS NMR. FT-IR, and UV Raman spectroscopies confirm the attachment of thiol functionalities in the mesoporous ethane-sificas. The maximum content of the attached thiol group (-SH) in the mesoporous framework is 2.48mmol/g. The ordered mesoporous materials are efficient Hg(2+) adsorbents with almost every -SH site accessible to Hg(2+). In the presence of various kinds of heavy metal ions such as Hg(2+), Cd(2+), Zn(2+), Cu(2+) and Cr(3+), the materials synthesized using poly(alkylene oxide) block cooollxmier (Pluronic 123) g(2+), as surfactant show almost similar affinity to Hg(2+), Cd(2+), and Cr(3+), while the materials synthesized using ofigomeric polymer C(18)H(37)(OCH(2)CH(2))(10)OH (Brij-76) as surfactant exhibit high selectivity to Hg(2+). (C) 2004 Elsevier Inc. All rights reserved.

Sensing hazardous metal ions using a fluoroionophore calix[4]arene species containing two 8-oxyquinoline groups

The interaction of a calix[4]arene-based species containing two 8-oxyquinoline chromophore pendants with hazardous metal ions has been investigated using optical absorption and fluorimetric techniques. In the presence of Hg(2+), Cd(2+), and Pb(2+) ions, there is only a small decrease of the calixarene absorption band at 283 nm. The main changes are associated with the absorption band of the 8-oxyquinoline group at 315 nm, undergoing a systematic bathochromic shift to above 350 nm. In addition, a systematic decrease of the oxyquinoline emission at lambda(em) = 392 nm (lambda(exc) = 315 nm) has been observed. These observations are consistent with the coordination of the metal ions to the quinoline groups attached to the calixarene ligand, providing a useful fluoroinophore species for analytical purposes.

A Single Intraoperative Sub-Tenon's Capsule Injection of Triamcinolone and Ciprofloxacin in a Controlled-Release System for Cataract Surgery

PURPOSE. To compare intraoperative injection of triamcinolone and ciprofloxacin in a controlled-release system (DuoCat) with prednisolone and ciprofloxacin eye drops after cataract surgery.METHODS. In this randomized, double-masked, controlled trial, a total of 135 patients undergoing cataract surgery were randomly allocated to two groups: 67 patients treated after surgery with prednisolone 1% and ciprofloxacin 3% eye drops four times daily (week 1), three times daily (week 2), twice daily (week 3), and once daily (week 4) and 0.3% ciprofloxacin drops four times daily (weeks 1 and 2), and 68 patients treated at the end of surgery with a sub-Tenon's injection of 25 mg triamcinolone and 2 mg ciprofloxacin in biodegradable microspheres. The patients were examined on postoperative days 1, 3, 7, 14, and 28. The main outcome measures were postoperative anterior chamber cell and flare, intraocular pressure (IOP), lack of anti-inflammatory response, and presence of infection.RESULTS. No significant differences were observed between the groups in anterior chamber cell (P > 0.14) and flare (P > 0.02) at any postoperative visits. The mean (99% confidence interval) differences in IOP between the prednisolone and triamcinolone groups on days 1, 3, 7, 14, and 28 were -0.4 mm Hg (-2.1 to 1.3), 0.0 mm Hg (-1.4 to 1.3), 0.0 mm Hg (-1.1 to 1.1), -0.2 mm Hg (-1.1 to 0.8), and -0.1 mm Hg (-1.1 to 0.9), respectively. No patient had a postoperative infection.CONCLUSIONS. One injection of DuoCat had a therapeutic response and ocular tolerance that were equivalent to conventional eye drops in controlling inflammation after cataract surgery. (Clinical-Trials. gov number, NCT00431028.) (Invest Ophthalmol Vis Sci. 2009; 50: 3041-3047) DOI: 10.1167/iovs.08-2920