四溴双酚-A污染对颤蚓的氧化胁迫及毒性

在实验室模拟条件下分别采用动、静态生物慢性实验的方法,研究了不同浓度的四溴双酚-A(Tetrabromobisphenol A, TBBPA)对颤蚓(Monopylephorus limosus)体内抗氧化酶系统及相Ⅱ结合酶系统活性的影响以及颤蚓暴露于单一浓度的TBBPA后,其体内抗氧化酶系统的活性随时间的响应.结果表明,暴露 8d 后,颤蚓体内SOD的活性发生显著变化,变化趋势明显分为升高、降低、再升高3阶段,在0.05ms/L时SOD的活性被最大诱导(p<0.01),达到对照组的7.8倍,各浓度组SOD的活性均显著高于对照组,由对照组的1.5倍到对照组的7.8倍;同时, CAT的活性变化则呈升高、降低、再升高、再降低4阶段,0.5mg/L时其活性达到最大值(p<0.01),除0.005mg/L和0.25mg/L浓度组CAT活性受抑制外,其余浓度组CAT的活性均高于对照组,由对照组的1.1倍到1.9倍,染毒浓度为0.25ms/L时, GST的活性达到最大诱导(p<0.01),其活性先缓慢上升后下降,并且各处理组GST的活性均显著高于对照组(p<0.05).在单一浓度TBBPA污染暴露的10d时间内,颤蚓体内SOD的活性变化趋势形成了一个变形的"M" 形曲线,在第3d时其活性达到最大诱导,而CAT活性的变化则表现为一个不规则的"N"形曲线,在第5d,时其活性达到最大诱导,并且SOD的活性比CAT的活性受时间的影响小,相对来说更稳定.可见, SOD与GST的活性变化似乎更能反映出TBBPA对颤蚓的污染效应及其毒性作用,而SOD的活性变化似乎更为灵敏,但是二者能否作为指示TBBPA污染的生物标志物尚需进一步研究.     

五氯酚对HeLa细胞毒性及DNA损伤的研究

以人宫颈癌HeLa细胞为研究对象,运用MTT法检测PCP处理后HeLa细胞的增长抑制率;通过测定细胞培养液中乳酸脱氢酶(LDH)的漏出率和总超氧化物歧化酶(SOD)的活性,评价PCP的细胞毒性作用;彗星实验检测HeLa细胞经不同浓度PCP处理后的DNA损伤.结果表明,PCP对HeLa细胞的半数抑制浓度(IC50)为66.59μmol.L-1;HeLa细胞在12.5、25、50、100和200μmol.L-1 PCP染毒条件下,LDH的漏出率随着染毒时间的增加逐渐增大,具有明显的时间-效应关系,在12.25、17.5和25μmol.L-1 PCP染毒下,细胞培养液中SOD的活性随着染毒时间的增加逐渐下降,存在显著的时间-效应关系,低浓度PCP(25μmol.L-1)显著增加细胞培养液中LDH的漏出率以及PCP(12.25μmol.L-1)显著降低总SOD的活性;PCP(实验浓度为6.25、12.5、25和50μmol.L-1)不会导致HeLa细胞DNA损伤.因此SOD和LDH可作为评价低浓度PCP毒性效应的敏感性生物标志物.     

商品氯氰菊酯农药对蛋白核小球藻的毒性效应研究

研究了氯氰菊酯对蛋白核小球藻(Chlorella pyrenoidosa)生长、细胞内含物(可溶性蛋白、可溶性糖)及抗氧化酶类(超氧化物歧化酶,SOD)、膜脂氧化产物(丙二醛,MDA)的影响.结果表明,在氯氰菊酯暴露下,藻细胞的生长受到不同程度的抑制,且抑制程度随氯氰菊酯浓度的增大而增大,氯氰菊酯对蛋白核小球藻生长的72h半效应浓度(EC50)为4.89mg·L-1.藻细胞所有生理生化指标对氯氰菊酯响应迅速,在暴露初期较为敏感,24h后趋于平稳.其中,可溶性糖和可溶性蛋白含量上升,中等浓度组(3.2,5.6mg·L-1)上升趋势最为显著.SOD活性则呈现出低浓度(1.0,1.8mg·L-1)促进、高浓度(>3.2mg·L-1)抑制效应.氯氰菊酯可使藻体内丙二醛(MDA)含量升高,氯氰菊酯浓度越高,藻体内MDA含量越高.研究结果表明,对藻细胞SOD活性的抑制及膜脂过氧化可能是氯氰菊酯对蛋白核小球藻产生毒害作用的重要原因.     

ZnO纳米粒子抑制体外小鼠光感受器细胞MnSOD的表达及活性

随着纳米技术的发展,纳米材料在生物医药以及化工中已得到广泛应用。作为一类新型材料,其安全性也日益受到人们的高度关注。为探索氧化锌(ZnO)纳米粒子对小鼠视网膜光感受器细胞的毒性作用,本文通过MTT、荧光染色、流式细胞术、实时荧光定量PCR和酶联免疫吸附试验(ELISA)等技术,分别对经不同浓度ZnO纳米粒子处理的小鼠光感受器细胞活性、活性氧水平、锰超氧化物歧化酶(Mn SOD)的基因和蛋白表达及活性进行了检测。结果表明,ZnO纳米粒子可通过诱导细胞线粒体产生过多的活性氧,降低线粒体膜电位,导致小鼠视网膜光感受器细胞损伤;ZnO纳米粒子能显著减少Mn SOD在mRNA和蛋白质水平的表达,降低Mn SOD活性,加剧氧化应激介导的细胞损伤。因此,氧化应激水平的提高导致了过量的活性氧产生及Mn SOD表达和活性的下降,与ZnO纳米粒子引起的细胞毒性作用有关。     

Pesticides and Essential Minerals Modify Endogenous Antioxidants and Cytochrome P450 in Tissues of Rats

Two experiments were conducted in male Sprague Dawley (SD) rats (175–200 g) to determine changes in the activities of endogenous antioxidants superoxide dismutase (SOD), glutathione peroxidase (GPX), cytochrome P450 (ethoxyresorufin deethylase; EROD) and concentrations of glutathione (GSH) in the blood, liver, and small intestinal mucosa (IM). In both experiments, six rats/group were fed diets based on the AIN-93M diet (Control) or the same modified to contain either 500 mg calcium (Low Ca), 7 mg Zn (Low Zn): 2 mg copper (Low Cu), 60 mg zinc (High Zn) or 12 mg copper (High Cu) in the following combination: Control, LCa/LZn, LCa/LZn/LCu, or HZn/HCu, with and without a pesticide mixture containing acephate, endosulfan, and thiram at 25% LD₅₀ for four or two weeks. Pesticides decreased feed intake and weight gain in all groups by 28%. Erythrocyte SOD was higher than control in the HZn/HCu group and in the LCa/LZn/LCu and HZn/HCu groups with pesticide (P# 0.05). Plasma GPX declined by more than 55% in all the groups with and without pesticides compared to the control. The LCa/LZn/LCu and HZn/HCu diets with and without pesticides reduced GPX in the IM by up to 88%, 40%, and 74%, respectively, than the control. Plasma GSH was about 20% higher than the control in most groups with and without pesticides in the diet. Liver and IM GSH were higher than the control in the HZn/HCu group, whereas IM GSH concentrations were lower than the control in the LCa/LZn and LCa/LZn/LCu groups (P#0.05). All three experimental diets with and without pesticides had a significant effect on liver EROD activity (P#0.05). The results indicate that endogenous antioxidants and EROD were independently modified by dietary zinc and copper levels and pesticides.     

Micronuclei Frequency in Lymphocytes and Antioxidants in the Blood of Traditional Limited-Resource Farm Workers Exposed to Pesticides

Chronic low-level exposure to synthetic pesticides is implicated in many health conditions that result from the induction of oxidative stress, including cytogenetic damage. The objective of this study was to assess the risk of genotoxicity using micronuclei (MN) formation in lymphocytes and to determine changes in blood antioxidants superoxide dismutase (SOD) in erythrocytes (E) and glutathione (GSH) in E and plasma (PL) in farm workers for six months during a growing season. Blood and urine samples were collected once a month for six months (June to November 2003) from farm workers (n = 15) and urban unexposed controls (n = 10). Lymphocytes from blood were separated by density gradient centrifugation using Histopaque and cultured using the standard technique. There was no significant difference in the cytokinesis blocked proliferation index (CBPI) of lymphocytes between the farm workers and the control group, but there was a 76% increase in average MN frequency in lymphocytes of the farm worker group (P ≤ 0.05). In addition, MN frequency peaked during August as compared to the other months and the controls (P ≤ 0.05). An 18% decline was observed in the activity of E-SOD in the farm worker group (P ≤ 0.05). GSH in E and PL were similar in both groups. These data suggest that the farm workers may be at a greater risk of developing genotoxicity due to continued exposure to pesticides, especially during the intensive growing season.     

柳树乙醇提取物体外抗氧化活性

通过Fenton反应产生.OH,邻苯三酚自氧化产生O2.-模型,研究了柳树乙醇提取物体外清除自由基的作用。结果显示,柳茎和柳叶乙醇提取物在3.125—50 mg/ml浓度范围内具有清除O2.-的作用。随着浓度升高,其清除作用增大。在浓度达到50mg/ml时,柳茎提取物的清除率为75.62%,柳叶提取物的清除率为88.53%;柳茎乙醇提取物在3.125—25 mg/ml浓度范围内,清除.OH的能力随着其浓度的增加而逐渐增强。当浓度为25mg/ml时,其清除率为60.63%;柳叶提取物在浓度3.125—25mg/ml内清除.OH的作用不明显。当浓度达到50mg/ml时,对羟基自由基的清除率为60.63%。     

Cobalt and manganese stress in the microalga Pavlova viridis （Prymnesiophyceae）： Effects on lipid peroxidation and antioxidant enzymes

Pollution of marine environment has become an issue of major concern in recent years.Serious environmental pollution by heavy metals results from their increasing utilization in industrial processes and because most heavy metals are transported into the marine environment and accumulated without decomposition.The aim of the present study is to investigate the effects on growth,pigments, lipid peroxidation,and some antioxidant enzyme activities of marine microalga Pavlova viridis,in response to elevated concentrations of cobalt(Co)and manganese(Mn),especially with regard to the involvement of antioxidative defences against heavy metal-induced oxidative stress.In response to Co~(2 ),lipid peroxidation was enhanced compared to the control,as an indication of the oxidative damage caused by metal concentration assayed in the microalgal cells but not Mn~(2 ).Exposure of Pavlova viridis to the two metals caused changes in enzyme activities in a different manner,depending on the metal assayed:after Co~(2 )treatments,total superoxide dismutase(SOD)activity was irregular,although it was not significantly affected by Mn~(2 )exposure.Co~(2 )and Mn~(2 )stimulated the activities of catalase(CAT)and glutathione(GSH),whereas,ghitathione peroxidase(GPX)showed a remarkable increase in activity in response to Co~(2 )treatments and decreased gradually with Mn~(2 )concentration,up to 50μmol/L,and then rose very rapidly,reaching to about 38.98% at 200μmol/L Mn~(2 ).These results suggest that an activation of some antioxidant enzymes was enhanced,to counteract the oxidative stress induced by the two metals at higher concentration.     

Effects of used lubricating oil on two mangroves Aegiceras corniculatum and Avicennia marina

An outdoor experiment was set up to investigate the effects of used lubricating oil(5 L/m~2)on Aegiceras corniculatum Blanco. and Avicennia marina(Forsk)Vierh.,two salt-excreting mangroves.A.marina was more sensitive to used lubricating oil than A. corniculatum and canopy-oiling resulted in more direct physical damage and stronger lethal effects than base-oiling.When treated with canopy-oiling,half of A.corniculatum plants survived for the whole treatment time(90 d);but,for A.marina,high mortality (83%)resulted from canopy-oiling within 3 weeks and no plants survived for 80 d.Base-oiling had no lethal effects on A.corniculatum plants even at the termination of this experiment,but 83% of A.marina plants died 80 d after treatment.Forty days after canopy- oiling,93% ofA.corniculatum leaves fell and no live leaves remained on A.marina plants.By the end of the experiment,base-oiling treatment resulted in about 45% ofA.corniculatum leaves falling,while all A.marina leaves and buds were burned to die.Lubricating oil resulted in physiological damage to A.corniculatum leaves,including decreases in chlorophyll and carotenoid contents,nitrate reductase,peroxidase and superoxide dismutase activities,and increases in malonaldehyde contents.For both species,oil pollution significantly reduced leaf,root,and total biomass,but did not significantly affect stem biomass.Oil pollution resulted in damage to the xylem vessels of fine roots but not to those of mediate roots.     

氮掺杂生物炭催化臭氧对于布洛芬的降解特性与机制

系统研究了新型氮掺杂生物炭材料(N-C)催化臭氧对于水中布洛芬(IBP)的氧化降解效能及机制,并深入探究了初始pH、臭氧投加量、催化剂投加量、不同阴离子和背景水质条件对IBP降解效率的影响.结果 表明,相较于一些常见的碳基催化剂(g-C3N4、生物炭、颗粒活性炭)及金属催化剂(MnO2、Fe3O4),N-C催化臭氧体系...