六氯苯对离体鱼肝线粒体抗氧化酶的作用

采用差速离心法从鲫鱼肝脏中提取线粒体,用不同浓度(0,2,4,8,16,32mg/L)六氯苯对其体外染毒30min.测定线粒体超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性,用聚丙烯酰胺凝胶电泳法分析其同工酶谱,并检测线粒体中丙二醛(MDA)含量.结果显示,SOD和GSH-Px活性及其同工酶的活性表达均呈现出低浓度六氯苯作用下被激活,高浓度六氯苯作用下被抑制的变化趋势.在高浓度六氯苯(32mg/L)作用下线粒体中MDA含量显著增加.说明六氯苯的毒性作用可能为一种自由基机制,即低浓度的六氯苯导致线粒体内活性氧自由基(ROS)生成量少量增加,SOD和GSH-Px及其同工酶活性由于氧化应激的诱导被激活;随着六氯苯浓度增加,线粒体内ROS生成量大量增加,并破坏了SOD和GSH-Px的抗氧化活性,导致其活力下降或丧失,自由基含量增加,线粒体脂质过氧化加剧.     

铝胁迫下外源钙对外生菌根真菌抗氧化保护酶活性的影响

采用液体培养方法,研究了4个不同菌株(Bo 02、Bo 15、Pt 715和Sl 08)的抗铝性及其在铝胁迫下加入0、0.25、0.5、1.0 mmol.-1L-1Ca2+处理后抗氧化保护酶活性的变化,旨在了解钙在缓解外生菌根真菌铝毒方面的作用.结果表明,不同菌株抗铝性不同,Pt 715和Sl 08的抗铝性强于Bo 02和Bo 15.铝胁迫可显著提高外生菌根真菌Bo 02 CAT和SOD活性、Bo 15SOD活性、Sl 08 CAT和POD活性,说明外生菌根真菌中这几种酶活性的提高与铝毒胁迫密切相关.4个菌株中,Bo 02酶活性对外源钙最敏感,外源钙对Bo 02铝胁迫的缓解作用最好.较高浓度的钙(≥0.5 mmol.L-1)可缓解或消除Sl 08铝胁迫造成的抗氧化酶活性上升.     

Reproductive toxicity and underlying mechanisms of di(2-ethylhexyl) phthalate in nematode Caenorhabditis elegans

DEHP (di(2-ethylhexyl) phthalate) is an endocrine disruptor commonly found in plastic products that has been associated with reproduction alterations, but the effect of DEHP on toxicity is still widely unknown. Using DEHP concentrations of 10, 1, and 0.1 mg/L, we showed that DEHP reduced the reproductive capacity of Caenorhabditis elegans after 72 hr. of exposure. DEHP exposure reduced the reproductive capacity in terms of decreased brood sizes, egg hatchability (0.1, 1 and 10 mg/L), and egg-laying rate (1 and 10 mg/L), and increased numbers of fertilized eggs in the uterus (1 and 10 mg/L). DEHP also caused damage to gonad development. DEHP decreased the total number of germline cells, and decreased the relative area of the gonad arm of all exposure groups, with worms in the 1 mg/L DEHP exposure group having the minimum gonad arm area. Additionally, DEHP caused a significant concentration‐dependent increase in the expression of unc-86. Autophagy and ROS contributed to the enhancement of DEHP toxicity in reducing reproductive capacity, and glutathione peroxidase and superoxide dismutase were activated as the antioxidant defense in this study. Hence, we found that DEHP has a dual effect on nematodes. Higher concentration (10 mg/L) DEHP can inhibit the expression of autophagy genes (atg-18, atg-7, bec-1, lgg-1 and unc-51), and lower concentrations (0.1 and 1 mg/L) can promote the expression of autophagy genes. Our data highlight the potential environmental risk of DEHP in inducing reproductive toxicity toward the gonad development and reproductive capacity of environmental organisms.     

Ultraviolet irradiation induced oxidative stress and response of antioxidant system in an intertidal macroalgae Corallina officinalis L.

The response of the antioxidant defense system of an intertidal macroalgae Corallina officinalis L. to different dosages of UV-B irradiation was investigated. Results showed that superoxide dimutase (SOD) and peroxidase (POX) increased and then maintained at a relatively stable level when subjected to UV-B irradiation. Catalase (CAT) activity under medium dosage of UV-B irradiation (Muv) and high dosage of UV-B irradiation (Huv) treatments were significantly decreased. Ascorbate peroxidase (APX) activity first remained unaltered and then increased in Huv treatment. In addition, the assay on isozymes was carried out using non-denaturing polyacrylamide gel electrophoresis (PAGE). The activities of some SOD isoforms were altered by UV-B. Two new bands (POX V and POX Ⅶ) appeared upon exposure to all three UV-B dosages. CAT Ⅲ activity was increased by low dosage of UV-B irradiation (Luv),whereas CAT Ⅲ and CAT Ⅳ disappeared when the alga was exposed to Muv and Huv. Two bands of APX (APX Ⅵ and APX Ⅶ)were increased and a new band (APX X) was observed under Huv exposure. H2O2 and thiobarbituric acid reacting substance (TBARS)increased under Muv and Huv treatments. Overall, UV-B protection mechanisms are partly inducible and to a certain extent sufficient to prevent the accumulation of damage in C officinalis.     

Cd胁迫对桐花树同工酶的影响

利用聚丙烯酰胺凝胶垂直板电泳方法,研究了不同浓度Cd胁迫对桐花树幼苗叶片过氧物酶(POD)、超氧化物歧化酶(SOD)、酯酶(EST)同工酶酶谱的影响.结果表明:Cd胁迫下POD和EST同工酶组成发生了较大的变化,酶带颜色深浅和条数均有变化.部分同工酶基因表达在镉胁迫下完全关闭而酶带消失,另一部分同工酶基因表达则被启动而有新的酶带产生.而SOD同工酶酶带的亮度强弱也有明显的变化.这说明桐花树体内POD,EST和SOD同工酶确实能够适应Cd胁迫而产生相应变化,从而调节细胞代谢,以抵抗逆境胁迫.     

The effects of exogenous salicylic acid on growth and H2O2-metabolizing enzymes in rice seedlings under lead stress

Salicylic acid （SA） was an essential component of the plant resistance to pathogens and also plays an important role in mediating plant response to some abiotic stress. The possible effects of SA on the growth and H2O2-metabolizing enzymes in rice seedlings under lead stress were studied. When rice seedlings grown in nutrient solution containing Pb^2＋ （0, 0.05, 0.15, 0.25 mmol/L） for 18 d, the plant biomass as well as the chlorophyll content of leaves decreased with increasing Pb concentration. The pre-treatment with SA （treated with 0.1 mmol/L SA for 48 h before Pb stress） partially protected seedlings from Pb toxicity. The chlorophyll contents were significant higher in leaves of Pb-exposed with SA pre-treatment seedlings than in Pb-exposed plants at the same Pb intensity. SA pre-treated alone could significantly increase the length of shoot and root of seedlings but the vigour difference was not marked under long-term exposure to Pb toxicity. SA pre-treated influence the H2O2 level in leaves of seedlings by up-regulating the activity of superoxide dismutase （SOD）, repressing the activity of catalase （CAT） and ascorbate peroxidase （APX） depending on the concentrations of Pb^2＋ in the growth medium. The results supported the conclusion that SA played a positive role in rice seedlings against Pb toxicity.     

Role of the reduction site in the fluorinated or sulfated TiO2 photocatalytic process

In this article,the effects of TiO_2 surface fluorination and sulfation,on the active oxygen species formed at the reduction site in the photocatalytic process,namely O_2~(?) and H_2O_2,were investigated from a new perspective.The superoxide radical,(O_2~(?)),was determined by colorimetry of nitroblue tetrazolium,a prominent O_2~(?) scavenger.Hydrogen peroxide (H_2O_2) was estimated by using the iodide-starch method.In the naked TiO_2 photocatalysis,O_2~(?) though less reactive,was a very important intermediate.When the TiO_2 surface was fluorinated,more O_2~(?) and H_2O_2 were produced,which indicated that the surface modification could greatly reduce the recombination of photogenerated electrons and holes,thus enhancing the photocatalytic rate.In the sulfated system,photocatalysis proceeded with a more complicated mechanism.These results added support to the view of fluoride-induced enhancement and sulfide's nonappreciable inhibition effect.     

酸和铝胁迫对锦鲤不同组织SOD活性的影响

该实验目的是研究酸(pH=5,Al=0μg/L)、铝(pH=7,Al=800μg/L)单独及联合(pH=5,Al=800μg/L)作用下,锦鲤鱼脑、肾、肝超氧化物歧化酶(SOD)活性的反应变化情况。结果表明,与对照组(pH=7,Al=0μg/L)相比,锦鲤鱼脑无论在酸、铝单独作用还是联合作用下,SOD活性在染毒第1天均显著降低(p<0.01),但随后酸铝联合组、单独作用组分别在3 d、9 d恢复正常;肾SOD则只有在酸铝联合作用下,且只有在染毒第1天产生显著抑制(p<0.01),随后也恢复正常;肝SOD则无论在何种情况下,均无抑制现象发生。     

十溴联苯醚(BDE-209)对离体条件下小鼠肾脏和脑组织SOD活力和MDA含量的影响

十溴联苯醚(decabromodiphenyl ether,BDE-209)是目前应用最广泛的的溴系阻燃剂,其环境风险引起很大关注。本实验以小鼠肾脏和脑组织为实验材料,研究了离体条件下BDE-209的急性氧化损伤效应。BDE-209染毒终浓度设置为0,1,2,4和8μg·mL-1,采用NBT和TBA法分别测定SOD(superoxide dismutase)活性和MDA(malondialdehyde)含量。结果显示,随着BDE-209染毒浓度的升高,小鼠肾脏和脑组织的SOD活性先升高后降低,较高染毒浓度组的SOD活性与对照组相比显著性降低;MDA含量逐渐上升,并且与对照组相比较高染毒浓度组的MDA含量显著上升。以上结果说明,离体条件下BDE-209对小鼠肾脏和脑组织能够产生急性氧化应激,并导致脂质过氧化损伤。     

稻田土壤细菌对重金属镉的氧化应激反应研究

研究重金属镉胁迫下稻田土壤大肠杆菌K12、枯草芽孢杆菌B19及Ralstonia eutropha DKC1中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和ATP酶活性等应激酶活性的短期(46 h)变化.结果表明,不同浓度镉对E.coli K12,B.subtilisB19和R.eutrophaDKC1培养不同时间的SOD、CAT和ATP酶活性均有不同程度的诱导作用,表现在前期、低浓度时激活,后期、高浓度时抑制,体现了不同微生物间的差异以及抗镉潜力的不同.3种指标间接地反映了环境中有毒有害物质的存在,且能在早期较灵敏地指示污染的影响,作为环境受到污染胁迫的细胞生化指标具有一定可行性.