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.     

Toxic effects of 1-methyl-3-octylimidazolium bromide on the wheat seedlings

The toxic effects of 1-methyl-3-octylimidazolium bromide ([C8mim]Br) on wheat seedlings were evaluated. Wheat seedlings were cultivated in aqueous solution with [C8mim]Br at di erent concentrations (0, 1, 2, 4, 6, 8 mg/L). The contents of photosynthetic pigment and proline, peroxidation of membrane lipid, and activities of antioxidation enzymes (superoxide dismutase, catalase, peroxidase and ascorbate peroxidase) in leaves were measured on day 7 after treatment with [C8mim]Br. The results showed that [C8mim]Br significantly decreased the contents of photosynthetic pigments, activities of antioxidant enzymes in the wheat leaves and in dry weight of seedlings, while increased the proline content and membrane lipid peroxidation. The results suggested that [C8mim]Br can inhibit photosynthesis and lead to oxidative stress to wheat seedlings.     

Interactions of zinc and cadmium toxicity in their effects on growth and in antioxidative systems in tomato plants （Solanum lycopersicum）

The interaction between zinc and cadmium was investigated in tomato plants (Solanum lycopersicum). Ten-day-old seedlings were treated with 10 mol/L CdCl2 associated to di erent concentrations of ZnCl2 (10, 50, 100, and 150 mol/L). Zn supply clearly reduced Cd accumulation in leaves and simultaneously increased Zn concentration. Cd induced oxidative stress in leaves as indicated by an increase in thiobarbituric acid-reactive substances (TBARS) level and chlorophyll breakdown. Furthermore, compared with control, Cdtreated plants had significantly higher activities of superoxide dismutase (SOD, EC 1.15.1.1), whereas, catalase (CAT, EC 1.111.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2) activities were significantly suppressed by Cd addition. Zn supplementation, at low level, restored and enhanced the functional activity of these enzymes (SOD, CAT, APX and GR) as compared to Cd-alone-treated plants. The beneficial e ect of adequate Zn level on Cd toxicity was confirmed by a significant decrease in TBARS level and restoration of chlorophyll content. However, when Zn was added at high level in combination with Cd there was an accumulation of oxidative stress, which was higher than that for Cd or excess Zn alone treatments. These results suggested that higher Zn concentrations and Cd are synergistic in their e ect on plant growth parameters and oxidative stress.     

Phytotoxicity of cadmium on protein, proline and antioxidant enzyme activities in growing Arachis hypogaea L. seedlings

Phytotoxicity of cadmium on growing Arachis hypogaea L. seedlings was studied. Seeds were exposed to 25, 50, and 100 μmol/L CdCl2 concentrations, for a period of 10, 15, 20 and 25 d. The extent of damage to chlorophyll, protein, proline, nitrate and nitrite reductase, antioxidant enzyme activity in leaves and roots were evaluated after 10 d of cadmium stress. The higher concentration of cadmium （100 μmol/L） resulted （leaves and roots） total chlorophyll 91.01%, protein 79.51%, 83.61%, nitrate reductase 79.39%, 80.72% and nitrite reductase 77.07%, 75.88% activity decreased with increase in cadmium concentrations and exposure periods. Cadmium caused significant changes in the activity of antioxidative enzymes. Contrastingly Cd treated plant tissues showed an increase in proline 159.87%, 239.6%, gluthion reductase （GR） 337.72%, 306.14%, superoxide disumutase （SOD） 688.56%, 381.72%, ascorbate peroxidase （APX） 226.47%, 252.14%, peroxidase （POD） 72.19%, 60.29% and catalase （CAT） 228.96%, 214.74% as compared to control. Cadmium stress caused a significant increase in the rate of SOD activity in leaves and roots of plant species. Results show the crop A. hypogaea is highly sensitive even at very low cadmium concentrations.     

UV-B辐射对小麦叶抗氧化系统的影响

研究了温室种植的小麦在０（ＣＫ）、８．８２ｋＪ／ｍ＾２（Ｔ１）和１２．６ｋＪ／ｍ＾２（Ｔ２）三种剂量的紫外线Ｂ（ＵＶ－Ｂ）辐射下抗氧化系统的变化及其原因。ＵＶ－Ｂ辐射诱导了Ｈ２Ｏ２的合成，还原型抗坏血酸和还原型谷胱甘肽含量的增加、过氧化氢酶、愈创木酚过氧化物酶、抗坏血酸过氧化物酶和谷胱甘肽还原酶活性升高，而类胡萝卜素稍有所降低、超氧歧化酶（ＳＯＤ）活几乎不受ＵＶ－Ｂ辐射影响，分析表明，ＵＶ－Ｂ辐射     

Study on the sensitivity to cadmium of marine fish Salaria basilisca（Pisces： Blennidae）

The present study tested the sensitivity of Salaria basilisca to water-cadmium (Cd) contamination. For this purpose, liver somatic index (LSI), Cd concentrations and the activities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were measured in the liver of S. basilisca exposed to Cd-contaminated water (2 mg Cd/L as CdCl2) for 14 and 28 d. The results showed that the LSI decreased significantly after 14 and 28 d of Cd-exposure. Cd bioaccumulation in the liver resulted in an increasing uptake up to 42 g/g dry weight after 28 d of exposure. Activities of CAT and SOD were significantly increased with increasing exposure time. A significant increase in GSH-Px activity, under Cd influence, was observed during 14-day exposure period (p < 0.0001). However, a significant decrease (p < 0.05) in this activity with respect to control fish was registered after 28 d of Cd-exposure. These results showed that Cd accumulation in the liver of S. basilisca could induce oxidative stress as demonstrated by changes in the antioxidant enzyme activities. Results also emphasized that S. basilisca may considered as a sensitive species to Cd exposure.     

Interactions of zinc and cadmium toxicity in their effects on growth and in antioxidative systems in tomato plants (Solanum lycopersicum)

The interaction between zinc and cadmium was investigated in tomato plants (Solanum lycopersicum). Ten-day-old seedlings were treated with 10 μmol/L CDC12 associated to different concentrations of ZnC12 (10, 50, 100, and 150 μmol/L). Zn supply clearly reduced Cd accumulation in leaves and simultaneously increased Zn concentration. Cd induced oxidative stress in leaves as indicated by an increase in thiobarbituric acid-reactive substances (TBARS) level and chlorophyll breakdown. Furthermore, compared with control, Cdtreate plants had significantly higher activities of superoxide dismutase (SOD, EC 1.15.1.1), whereas, catalase (CAT, EC 1.111.1.6),ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2) activities were significantly suppressed by Cd addition. Zn supplementation, at low level, restored and enhanced the functional activity of these enzymes (SOD, CAT, APX and GR) as compared to Cd-alone-treated plants. The beneficial effect of adequate Zn level on Cd toxicity was confirmed by a significant decrease in TBARS level and restoration of chlorophyll content. However, when Zn was added at high level in combination with Cd there was an accumulation of oxidative stress, which was higher than that for Cd or excess Zn alone treatments. These results suggested that higher Zn concentrations and Cd are synergistic in their effect on plant growth parameters and oxidative stress.     

镉对背角无齿蚌外套膜和鳃抗氧化酶活性及脂质过氧化的影响

为了探究镉对背角无齿蚌(A.woodiana woodiana)外套膜和鳃抗氧化酶活性及脂质过氧化的影响,按照96 h的LC50为134.9 mg·L-1,分别于镉(Cd2+)浓度为4.22、8.43、16.82、33.7和67.45 mg·L-1,染毒24、48、72和96 h后测定背角无齿蚌外套膜和鳃中抗氧化酶包括超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GPX)和过氧化氢酶(CAT)活性及脂质过氧化产物丙二醛(MDA)的含量.结果表明,背角无齿蚌在不同浓度镉(Cd2+)溶液中经急性毒性处理24、48、72和96 h后,外套膜抗氧化酶活性呈现“抑制-诱导-抑制”的规律性变化,鳃抗氧化酶活性呈现“诱导-抑制”的规律性变化.镉处理后的背角无齿蚌外套膜和鳃SOD、GPX和CAT活性,表现出明显的组织差异性,且鳃诱导SOD、GPX和CAT活性较外套膜早.经镉处理以后,外套膜和鳃中MDA含量呈现升高趋势,高浓度镉处理组较对照组脂质过氧化损伤出现显著差异(**p＜0.01),具有剂量-效应和时间-效应.     

苯醚甲环唑对斑马鱼抗氧化酶的影响

以斑马鱼为模式生物研究了三唑类杀菌剂苯醚甲环唑对斑马鱼脑和肝脏中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)和谷胱甘肽还原酶(GR)四种抗氧化酶活性的影响.结果发现:苯醚甲环唑暴露后,斑马鱼脑中CAT酶活性随暴露时间延长呈现出先升高后降低的趋势.50μg/L及更高浓度的苯醚甲环唑能够显著抑制斑马鱼脑和肝脏中GPx的活性,且对脑中GPx活性的抑制程度更强.另外,500μg/L苯醚甲环唑处理后,斑马鱼肝脏和脑中GR活性表现出不同的变化趋势,肝脏中GR活性下降,而脑中GR活性升高.上述结果表明50μg/L的苯醚甲环唑即可影响斑马鱼的抗氧化系统,其对农业水域中的鱼类影响值得重视.     

不同光强下镉胁迫对紫茉莉光合作用和抗氧化系统的影响

通过土培实验,比较分析了3种光强(全光照(HL)、50%全光照(ML)和10%全光照(LL))下镉胁迫(30 mg·kg-1)对紫茉莉植株生长、光合作用、光合色素、镉、镁、铁和钾含量、脂质过氧化、抗氧化酶活性、抗坏血酸和谷胱甘肽含量的影响.结果发现,镉胁迫显著降低紫茉莉叶片的净光合速率,对HL植株的抑制程度高于ML和LL植株;HL和LL植株最大光化学效率在镉胁迫下显著降低,而ML植株所受影响不明显;镉胁迫显著提高了紫茉莉叶片的暗呼吸速率,ML植株提高幅度最大.镉胁迫对紫茉莉植株生长的抑制作用显著,对HL植株的抑制最大.镉胁迫显著增加了紫茉莉叶片的镉含量,减小叶片叶绿素、类胡萝卜素、Mg、Fe和K的含量,对HL植株影响最大.镉胁迫下,HL植株超氧化物歧化酶和过氧化物酶活性增强,过氧化氢酶和抗坏血酸过氧化物酶活性降低,谷胱甘肽和抗坏血酸含量减小,过氧化氢和丙二醛含量、超氧阴离子产生速率增高,电解质渗漏加重.上述结果表明,镉加重了叶片氧化胁迫程度和强化了对紫茉莉生长的抑制,特别在高光强条件下.     

纳米二氧化钛对金鱼脑组织的氧化应激损伤

为探讨光催化型nano-TiO₂(纳米二氧化钛)对金鱼(Carassius auratus L.)脑组织的氧化应激损伤效应,以5 nm的锐钛型钛白粉为试验材料,分别在ρ(nano-TiO₂)为0、16、32、64、128 mg/L下对金鱼进行处理,测定金鱼脑组织MDA(丙二醛)、PC(羰基化蛋白)和H₂O₂含量,SOD(超氧化物歧化酶)和GPx(谷胱甘肽过氧化物酶)活性以及Cu/Zn-SOD蛋白表达量. 结果表明:ρ(nano-TiO₂)从0 mg/L升至128 mg/L,金鱼脑组织Cu/Zn-SOD活性从1.70×10-3 kat/kg(以鲜质量计,下同)降至0.35×10-3 kat/kg,再回升至0.46×10-3 kat/kg; Mn-SOD活性呈降—升—降趋势,MDA含量从0.85 nmol/g升至2.83 nmol/g,之后降至2.54 nmol/g;PC含量一直上升;H₂O₂含量从4.32 μmol/g升至9.28 μmol/g,之后降至8.38 μmol/g. 随着ρ(nano-TiO₂)的加大,Cu/Zn-SOD蛋白表达量逐渐减少. 研究表明,nano-TiO₂对金鱼脑组织具有很强的氧化损伤作用,MDA与PC含量升高与Cu/Zn-SOD和GPx活性下降相关,H₂O₂含量升高与GPx活性下降等因素有关.      

Oxidative stress and DNA damages induced by cadmium accumulation

Experimental evidence shows that cadmium （Cd） could induce oxidative stress and then causes DNA damage in animal cells, however, whether such effect exists in plants is still unclear. In the present study, Vicia faba plants was exposed to 5 and 10 mg/L Cd for 4 d to investigate the distribution of Cd in plant, the metal effects on the cell lipids, antioxidative enzymes and DNA damages in leaves. Cd induced an increase in Cd concentrations in plants. An enhanced level of lipid peroxidation in leaves and an enhanced concentration of H2O2 in root tissues suggested that Cd caused oxidative stress in Vicia faba. Compared with control, Cd-induced enhancement in superoxide dismutase activity was significant at 5 mg/L than at 10 mg/kg in leaves, by contrast, catalase and peroxidaseactivities were significantly suppressed by Cd addition. DNA damage was detected by neutral/neutral, alkaline/neutral and alkaline/alkaline Comet assay. Increased levels of DNA damages induced by Cd occurred with reference to oxidative stress in leaves, therefore, oxidative stress induced by Cd accumulation in plants contributed to DNA damages and was possibly an important mechanism of Cd-phytotoxicity in Vicia faba plants.     

Coking wastewater increases micronucleus frequency in mouse in vivo via oxidative stress

Coking wastewater has caused serious health risk in coal-producing areas of China, however its toxic effects have not been well understood. The genotoxicity induced by coking wastewater on mice in vivo and its possible oxidative mechanisms were investigated via observing the induction of micronuclei in polychromatic erythrocytes of mouse bone marrow, and subsequently determining the antioxidative enzyme activities （superoxide dismutase Cu, Zn-SOD, Se-dependent glutathione peroxidase, and catalase）, thiobarbituric acid reactive substance contents and protein carbonyl levels in brains and livers of mice. Results showed that the tested coking wastewater caused a significant increase of micronucleus frequencies in a concentration-dependent manner. Also, the sample increased lipid peroxidation and protein oxidation levels, which was accompanied by changes in antioxidative status. Interestingly, pre-treatment with an antioxidant （vitamin C） led to a statistical reduction in the micronucleus frequency caused by coking wastewater. This implies that coking wastewater induces evident genetic damage in mammalian cells, and exposure to polluted areas might pose a potential genotoxic risk to human beings; in the process, oxidative stress played a crucial role.     

水体二价铜离子致蟾蜍蝌蚪DNA损伤和氧化损伤

为研究水体二价铜离子(Cu2 )暴露对蝌蚪造成的损伤,以常见的中华大蟾蜍蝌蚪为研究对象,采用标准水生生物毒性实验法,将蝌蚪暴露于0.029、0.037、0.049、0.075 mg·L-1的铜溶液中7d,检测蝌蚪血细胞DNA损伤及机体过氧化产物丙二醛(MDA)、还原型谷胱甘肽(GSH)的含量,以及超氧化物歧化酶(SOD)、谷肮甘肽过氧化物酶(GSH-Px)和过氧化氢酶(CAT)活性.结果表明,随铜暴露浓度的增加,蝌蚪血细胞DNA损伤、MDA和GSH含量与对照组比均有明显升高,且呈浓度-效应关系.蝌蚪SOD、CAT、GSH-Px酶活性也有显著改变;MDA、GSH、DNA损伤均呈线性关系(R2分别为0.9968、0.8997).上述结果表明,水体二价铜离子可导致蝌蚪的氧化损伤和DNA损伤.     

2,4-二氯苯酚低浓度长期暴露对鲫鱼肝脏抗氧化系统的影响

在室内模拟条件下,研究了低浓度2,4-二氯苯酚(2,4-DCP)长期暴露(40d)对鲫鱼(Carassius auratus)幼体肝脏抗氧化系统的影响结果表明:过氧化氢酶(CAT)活性、谷胱甘肽过氧化物酶(Se-GPx)活性、氧化型谷胱甘肽(GSSG)含量可被显著诱导;超氧化物歧化酶(SOD)活性在0.005mg·L^-1 2,4-DCP污染胁迫下即被显著诱导;还原型谷胱甘肽(GSH)含量几乎持续受到抑制;谷胱甘肽还原酶(GR)活性则先受到抑制后逐渐回升;谷胱甘肽硫转移酶(GST)的活性变化较小,仅在2个低浓度组中有轻微诱导.GR、GSH,尤其是SOD,对2,4-DCP较为敏感,可以作为水生生态系统中2,4-DCP污染的一项早期监测指标.     

a-亚麻酸对赤潮异弯藻生长的抑制作用

探讨了a-亚麻酸对赤潮异弯藻(Heterosigma akashiwo)生长的抑制作用,并从细胞膜渗透性、抗氧化酶系和光合放氧量等方面研究了其抑制机理.结果表明,a-亚麻酸对赤潮异弯藻有明显的抑制作用,其第7d的IC50为2.4μL/L.在a-亚麻酸作用下,细胞内Na+、K+、Mg2+和Ca2+浓度随着实验的进行受到不同程度的影响,在36h后都出现明显的下降;藻细胞内可溶性蛋白质含量下降,超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT).在8h时明显高于对照组,之后逐渐下降,到36h时低于对照组;丙二醛含量(MDA)表征了脂质过氧化强度和膜系统受损程度,其在12h时明显高于对照组,之后慢慢下降;藻细胞的光合放氧量呈逐渐下降趋势.结果表明,a-亚麻酸通过改变细胞膜透性和自由基反应,从而破坏藻细胞的结构,进而达到抑藻的效果.     

钝顶螺旋藻对Cd胁迫的生理反应

研究了钝顶螺旋藻在Cd胁迫下的生理指标的变化.结果表明,在CdCl2浓度为0～24 mg/L范围的Cd胁迫下,随着CdCl2浓度的增加,可溶性蛋白的含量明显低于对照组,抗氧化系统也受到了不同程度的影响.SOD(超氧化物歧化酶)和POD(过氧化物酶)活力呈先增后降趋势,其中POD活力增加的程度较大,最高可达对照的360%,最低也为对照组的262%.在0～24 mg/L浓度范围内,APX(抗坏血酸氧化酶)活力均低于对照组,但随CdCl2浓度的增加呈递增状态.CAT(过氧化氢酶)均高于对照组,整体呈增加的趋势.GSH-PX(谷胱甘肽过氧化物酶)活力均低于对照,最低降至对照组的25%.MDA(丙二醛)作为膜脂质过氧化的产物,其累积是Cd胁迫的突出的生理变化之一,MDA的含量与CdCl2的浓度呈正相关.     

丛枝菌根真菌对汞胁迫下水稻叶片生理和光合特性的影响

为了研究AM（arbuscular mycorrhizal,丛枝菌根）真菌在Hg胁迫下对农作物生长的影响,通过温室盆栽试验,分析不同Hg投加量（0、0.1、1.0和2.0 mg/kg）下,接种AM真菌对水稻植株生物量、株高、叶片叶绿素相对含量、膜质过氧化程度、抗氧化酶系活性、光合速率、气孔导度、胞间CO₂、水分利用效率、可溶性糖和可溶性蛋白含量的影响.结果表明:①在不同Hg投加量下,AM真菌均能促进水稻植株生长.②AM真菌接种能提高水稻叶片叶绿素相对含量,增加水稻叶片光合速率.③接种AM真菌后,水稻叶片MDA（malondialdehyde）含量降低,水稻叶片超氧化物歧化酶（superoxide dismutase,SOD）、过氧化氢酶（catalase,CAT）、过氧化物酶（peroxidase）和抗坏血酸过氧化物酶（ascorbate peroxidase,APX）活性均升高.综合显著性分析结果来看,当Hg投加量为0.1 mg/kg时,接种AM真菌后水稻整体长势良好,多项生理指标偏高,说明AM真菌在较低Hg投加量下能促进水稻生长,提高水稻对汞的抗性.研究显示,AM真菌能通过促进水稻光合色素分泌来提高水稻光合作用,同时能提高水稻抗氧化酶活性,维持细胞稳态,缓解汞的毒害作用.总之,AM真菌能增强水稻对汞污染的适应能力,促进植株生长发育,降低汞对水稻造成的毒害及损伤,增强抗逆性,且该作用在较低Hg投加量下表现更加明显.      

Acute and chronic toxic effects of Pb2+ on polychaete Perinereis aibuhitensis：Morphological changes and responses of the antioxidant system

Perinereis aibuhitensis was used to assess adverse biological effects caused by acute and chronic Pb2＋exposure in artificial seawater under controlled laboratory conditions. In 96-hr acute toxicity experiments,the morphological changes showed a positive time/dose-dependent tendency,and the 96-hr LC50 value of Pb2＋was 686.41 mg/L. The responses of enzymatic and non-enzymatic antioxidants in tissues including catalase（CAT）,peroxidase（POD）,superoxide dismutase（SOD）,glutathione peroxidase（GSH-PX）,malondialdehyde（MDA） and the content of total soluble protein（TSP）,were investigated on days 1,4,7 and 10 after Pb2＋exposure under chronic toxicity testing. Results showed that the activation of the antioxidant system in P. aibuhitensis depended on the Pb2＋concentration and the duration of exposure time.Specifically,POD and SOD activities were induced on the first day of the exposure and decreased to the control level on day 10 after exposure. Therefore,these two indexes could be used to indicate oxidative stress associated with P. aibuhitensis exposure to Pb2＋.     

北部湾文蛤对石油烃和多氯联苯的氧化应激响应

为探讨海域现场双壳类动物对有机污染物积累的抗氧化响应,在北部湾潮间带11个采样点采集文蛤(Meretrix meretrix)样品,测定其软组织中w(TPHs)(TPHs为石油烃)、w(PCBs)(PCBs为多氯联苯)以及鳃、内脏中GSH(还原型谷胱甘肽),GSSG(氧化型谷胱甘肽)、SOD(超氧化物歧化酶)、CAT(过氧化氢酶)、GPx(谷胱甘肽过氧化物酶)、GST(谷胱甘肽转硫酶)、TBARS(硫代巴比妥酸反应物)7种氧化应激物的水平,分析其空间分布特征,并进行有机污染物含量与氧化应激物响应值之间的相关性分析. 结果表明:文蛤软组织中w(TPHs)和w(PCBs)分别为78.22~300.71μg/g和4.23~26.68ng/g,最大值均出现在S10采样点(防城港西湾);内脏中CAT活性较高,其他氧化应激物均在鳃中有较高水平. 与对照采样点S1(湛江流沙湾)相比,S2、S3、S6、S10、S11等5个采样点文蛤组织内SOD、CAT、GST、GPx、GSH水平较低;大多数采样点文蛤鳃中w(GSSG)较低,而S3、S4、S6、S7、S9、S11等6个采样点文蛤内脏中w(GSSG)较高;大多数采样点文蛤组织中TBARS含量较低,表明其抗氧化防御机能尚未丧失. TPHs显著抑制文蛤鳃中的w(GSSG) (R=-0.64,P<0.05),PCBs显著抑制文蛤鳃中的GPx(R=-0.72,P<0.05)和GST(R=-0.72,P<0.05)的活性,表明w(GSSG)及GPx和GST的活性可作为指示北部湾有机污染的生物标志物.