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. 

Oxidative Stress Responses to Total Petroleum Hydrocarbons and Polychlorinated Biphenyls in Meretrix meretrix in the Beibu Bay

In order to investigate the oxidative stress responses to organic contaminants accumulated in bivalves of Meretrix meretrix, the clam samples were collected from eleven sites along the coast of Beibu Bay. First, The total petroleum hydrocarbons (TPHs) and polychlorinated biphenyls (PCBs) were analyzed in the soft tissue of clams. Activity of reduced glutathione (GSH), oxidized glutathione (GSSG), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), and catalase (CAT) and oxidative damage marker (thiobarbituric acid reactive substances, TBARs) were quantified for the tissues of gill and liver respectively. The spatial distribution of contaminants was further explored. Finally, the regressive relationship between activity of antioxidant enzymes and the content of contaminants in clams was statistically examined. Results showed that the concentrations of TPHs and PCBs (wet weight) ranged from 78.22-300.71μg/g and from 4.23-26.68ng/g respectively in the soft tissue of clams. The highest levels for both contaminants were obtained at the sampling site S10in the western Fangchenggang Bay. The levels of CAT for liver were statistically higher than those in gill tissue for all samples. However other indices in hepatic tissue were remarkbly lower than those in gill. The activity levels of SOD, CAT, GST, GPx and GSH in five sites including S2,S3,S6,S10,S11were significantly inhibited compared with the control site (S1, in Liusha Bay of Zhanjiang). Levels of GSSG in gill were low in most of sites. However, levels of hepatic GSSG were high in clams from six sites such as S3,S4,S6,S7,S9,S11. The content of TBARS tested in clams from majority of sites was relatively low and this indicated that the antioxidant defense system of clams was not obviously destroyed. Content of GSSG (R=-0.64, P<0.05, for TPHs), activity of GPx (R=-0.72, P<0.05, for PCBs) and GST (R=-0.72, P<0.05, for PCBs) were significantly inhibited in gill and this indicated that the indices could be used as biomarkers to detect organic pollutants in the Beibu Bay.