喜旱莲子草对钉螺脂酶同工酶影响的初步研究

用不同浓度的喜旱莲子草水浸液处理钉螺24h,观察其灭螺效果,并用聚丙酰胺凝胶电泳技术比较研究了水浸液对钉螺酯酶同工酶的影响,结果表明:钉螺头足部肌肉的酯酶同工酶在低浓度(0.01g/L)时,活性较强,随水浸液处理浓度升高,活性迅速降低;而肝脏的酯酶同工酶在中等浓度(0.1g/L)时,活性最强,高浓度时(1g/L)有些酶带发生分解、消失。钉螺的死亡率则随着处理浓度的提高,急剧增大。喜旱莲子草干粉水浸液对钉螺酯酶同工酶影响明显,是引起钉螺中毒死亡的原因之一。这为喜旱莲子草作为新型植物灭螺剂的开发打下基础。     

纤维素高效降解菌NU-H的诱变选育及降解特性

以草酸青霉(Penicillium oxalicum)D1为出发菌株,经过紫外线、亚硝酸以及紫外与亚硝酸复合诱变处理,选育出1株高产纤维素酶突变株NU-H,与出发菌株相比,CMCase酶活提高69.8%,滤纸酶活提高75.28%,另外木聚糖酶活,还原糖得率也有显著地提高。通过单因子及正交实验,研究了突变株纤维素酶对稻草粉水解的最适宜条件。结果表明,该菌株酶解糖化的最佳条件为:温度50℃,时间28 h,纤维素酶浓度为60%,底物浓度3%,pH 4.8,还原糖得率为23.25%。     

Effect of nitrification inhibitor DMPP on nitrogen leaching, nitrifying organisms, and enzyme activities in a rice-oilseed rape cropping system

DMPP （3,4-dimethylpyrazole phosphate） has been used to reduce nitrogen （N） loss from leaching or denitrification and to improve N supply in agricultural land. However, its impact on soil nitrifying organisms and enzyme activities involved in N cycling is largely unknown. Therefore, an on-farm experiment, for two years, has been conducted, to elucidate the effects of DMPP on mineral N （NH4^＋- N and NO3^--N） leaching, nitrifying organisms, and denitrifying enzymes in a rice-oilseed rape cropping system. Three treatments including urea alone （UA）, urea ＋ 1% DMPP （DP）, and no fertilizer （CK）, have been carded out. The results showed that DP enhanced the mean NH4^＋-N concentrations by 19.1%-24.3%, but reduced the mean NO3^--N concentrations by 44.9%-56.6% in the leachate, under a two-year rice-rape rotation, compared to the UA treatment. The population of ammonia oxidizing bacteria, the activity of nitrate reductase, and nitrite reductase in the DP treatment decreased about 24.5%-30.9%, 14.9%-43.5%, and 14.7%-31.6%, respectively, as compared to the UA treatment. However, nitrite oxidizing bacteria and hydroxylamine reductase remained almost unaffected by DMPP. It is proposed that DMPP has the potential to either reduce NO3^--N leaching by inhibiting ammonia oxidization or N losses from denitrification, which is in favor of the N conversations in the rice-oilseed rape cropping system.     

大气细颗粒物(PM2.5)对心血管内皮细胞NOS的影响

运用体外试验方法,探讨了大气细颗粒物的心血管毒性及其可能的作用机制采集上海城区大气中的PM25,并以0.01、0.05、0.2、1 mg·mL-1剂量染毒大鼠心血管内皮细胞24 h后,观察PM2.5对心血管内皮细胞内总NOS,iNOS及cNOS活力等指标的影响.发现与对照组相比,0.2 mg·mL-1染毒组的心血管内皮细胞总NOS和iNOS活力显著增加,而cNOS活力显著降低,并且随着PM25染毒剂量的增加,存在剂量-反应关系.这一结果表明,PM2.5可通过诱导心血管内皮细胞的iNOS活性,对心血管系统产生氧化应激损伤,氧化应激作用可能是PM2.5心血管系统毒性的作用机制之一.     

小麦中T-2毒素酶联免疫吸附测定法(ELISA)

T-2毒素是某些植物致病菌的次生代谢产物,尤其是由镰刀菌(Fusarium sp)引致的麦类、玉米等作物的赤霉病,菌体在一定条件下能产生大量的该类毒素.T-2毒素对人畜的毒性很大,同时,还与某些癌症的发病率有密切的关系.T-2毒素的检测方法,常用的有薄层层析法,气相、液相色谱法以及气-质联用等,这些方法,有的精确度     

利用乙酰胆碱酯酶传感器监测海水久效磷

用戊二醛(GA)将乙酰胆碱醇酶(ACHE)交联在透析膜上,并与pH电极结合,由此开发出一种基于固定化酶的电位型传感器。该酶电极可以快速、灵敏地测定海水中的久效磷。仪器对海水中10^-10～10^-7的久效磷农药具有极好的线性响应,检测下限为0．1μg／L,加标回收率在90％～103％之间,分析1个海水样品只需50min。     

Oxidative stress related enzymes in response to chromium (Ⅵ) toxicity in Oxya chinensis ( Orthoptera : Acridoidae)

The toxic effects of Cr（Vl） on antioxidant enzymes of Oxya chinensis（Orthoptera： Acridoidae） were determined. Changes in the activities of the antioxidant enzymes superoxide dismutase（SOD）, catalase（CAT）, and guaiacol peroxidase（GPx） were measured in O. chinensis insects injected with Cr（VI）. Fifth-nymphs of O. chinensis insects were injected with Cr（VI） with different concentrations （0, 75, 150, 225, 300, 375, 450 mg/kg of body weight）. The results showed that Cr（VI） led to the change of SOD, CAT, and GPx activities at different concentrations, which revealed that： （1） The oxidative stress of SOD increased with the increase of Cr （VI） concentration. （2） With the increase of Cr （VI） concentrations, CAT activities for females increased at lower concentrations, but decreased at higher concentration range, which indicated that antioxidant system of O. chinensis was not influenced by the presence of Cr （VI）. A very similar response to Cr（VI） effect for males indicated that Cr（VI） concentrations were not high enough to damage O. chinensis in terms of CAT. （3） The GPx activity for females increased in all treatments, which revealed that the damage power of Cr（VI） was increased with the increase of Cr（Vi） concentrations in terms of GPx, but the effect was not so remarkable. There was not a consistent trend of GPx activities for males in all treatments of Cr（VI）. Cr（VI）-induced changes in antioxidant enzymes were different for SOD, CAT and GPx, of which the tendency was that activities generally changed with increase of concentrations of Cr（VI） suggesting SOD, CAT, and GPx could serve as indices of oxidative stress to some extent.     

NO在甲醛介导的氧化损伤中的协同作用

为了探讨NO在甲醛介导的氧化损伤中的协同作用,用不同剂量的气态甲醛对小鼠进行连续动态染毒处理72 h后,测定小鼠脑、心和肝组织一氧化氮合酶活力和总抗氧化能力.结果显示,吸入甲醛后,小鼠的脑、心和肝组织一氧化氮合酶活力升高,总抗氧化能力下降.当甲醛浓度为0.5 mg·m-3时,脑和肝的一氧化氮合酶活力与阴性对照组相比有显著性差异(p＜0.05),脑和肝的总抗氧化能力与阴性对照组相比,有极显著性差异(p＜0.01),而心的总抗氧化能力与阴性对照组相比有显著性差异(p＜0.05).当甲醛浓度上升为3.0 mg·m-2时,脑、心和肝组织的一氧化氮合酶活力和总抗氧化能力与阴性对照组相比均有极显著性差异(p＜0.01).结果表明,过量生成的NO是甲醛导致机体氧化损伤可能的机理.