Tissue-Specific Recovery of Oxidative and Antioxidant Effects of Chlorpyrifos in the Freshwater Crab,Barytelphusa guerini

Chlorpyrifos (CPF), an organophosphate widely applied in agriculture and aquaculture, induces oxidative stress due to free-radical generation and changes in the antioxidant defense system. The present study investigated the short-term effect of CPF exposure on the oxidative and antioxidant systems and their recovery responses in metabolically active tissues (gills, hepatopancreas [HP], and leg muscle) of freshwater crab Barytelphusa guerini. Crabs were exposed to a sublethal concentration of CPF (0.07 mg L^?1) for a total of 8 days (at intervals of 1, 2, 4, and 8 days) in clean water. The following oxidative stress markers were measured: acetylcholinesterase (AChE), butylcholinesterase (BChE), and ATPase; antioxidants i.e., superoxide dismutase (SOD), catalase, and glutathione reductase (GR), lipid peroxidation (LPO), conjugating enzyme glutathione S-transferase (GST), glutathione peroxidase (GPx), and lipid content. CPF exposure led to a significant decrease in the activity of oxidative stress markers as follows: AChE (84 %), BChE (46 %), and gills Na⁺/K⁺ ATPase (62 %). At the end of the recovery period, enzyme levels were recovered except in leg muscle. Total lipids and SOD decreased; CAT and LPO levels increased; and GPx, GR, and GST showed tissue-specific activities. Maximum recovery was observed in GPx followed by GR in HP tissue of crab. Nevertheless, these responses apparently grant successful adaptation for survival in a pesticide-extreme environment.     

Oxidative stress and genotoxic responses to resin acids in Mediterranean mussels

This study represents the first attempt to investigate the genotoxic effects and oxidative stress of resin acids in Mediterranean mussels (Mytilus galloprovincialis Lmk). Mussels were exposed to 2.7 microM abietic acid (AA) and dehydroabietic acid (DHAA) for 6, 12, 18, and 24h. Gill and hepatopancreas conjugation activity, antioxidant defense system, lipid peroxidation (LPO), and DNA damage were determined as reduced glutathione (GSH), glutathione S-transferase (GST) activity, glutathione peroxidase (GPx) activity, catalase (CAT) activity, LPO, and DNA strand breaks. AA caused significant GST inhibition in mussel gills at 12, 18, and 24h. Activity of the antioxidant enzymes, namely, GPx and CAT, was inhibited at 24 and 18 h, respectively, in mussel gills. A significant increase in gill LPO was observed at 24h. The DNA integrity of mussel hepatopancreas significantly decreased after 12 and 24 h exposure to AA. A significant increase in LPO was observed after 6h exposure to DHAA, in either mussel gills or hepatopancreas. DNA integrity was significantly decreased in mussel hepatopancreas after 12 and 24 h exposure to DHAA. AA induced oxidative damage and genotoxicity in mussels, because it promoted increases in LPO in gills and DNA strand breaks in hepatopancreas. DHAA promoted oxidative damage and genotoxicity in mussels, as significant increases were observed in LPO in gills and hepatopancreas and in DNA strand breaks in hepatopancreas.     

Response of integrated biomarkers of fish (Lateolabrax japonicus) exposed to benzo[a]pyrene and sodium dodecylbenzene sulfonate

Fish Lateolabrax japonicus were exposed to 0.1 and 1mg/L of anion surfactant sodium dodecylbenzene sulfonate (SDBS) and to 2 and 20 microg/L of benzo[a]pyrene (B[a]P) for 6, 12, and 18 days, with control and solvent control groups. Liver antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), and glutathione S-transferase (GST), were determined; brain acetylcholinesterase (AChE) and liver inducible nitric oxide synthase (iNOS) activities were also measured. The results indicated that (1) L. japonicus avoided oxidative damage through antioxidant systems; (2) SOD, GPx, and GSH were induced, and GST was inhibited and then induced by B[a]P exposure; and (3) CAT, GPx, and AChE were induced while iNOS was inhibited, and GST was induced and then inhibited by SDBS stress in experimental period.     

Modulatory Effects of Deltamethrin on Antioxidant Defense Mechanisms and Lipid Peroxidation in Carassius auratus gibelio Liver and Intestine

Pyrethroids, such as deltamethrin, are toxic substances that lead to generation of reactive oxygen species, which harm living organisms. We assessed the level and patterns of imbalance evolved by a single dose of 2 μg/L deltamethrin on the lipid peroxidation (LPO) and the antioxidant defense system of Carassius auratus gibelio liver and intestine, and monitored the recovery dynamics of these parameters during a 14-day post-exposure period. LPO and antioxidative defense mechanisms displayed different responses in the investigated tissues. Sudden increase of LPO in the liver, persisting at this elevated level throughout the test period, was observed on the third day post-exposure, while in the intestine significant enhancement of this parameter was recorded from the seventh day. Reduced glutathione (GSH) showed a transient increase in the liver, and was depleted in the intestine by the second day of exposure, with signs of recovery by the end of the experimental tenure. In the liver of fish a temporary inhibition of superoxide dismutase (SOD) and catalase (CAT) activity, and activation of glutathione peroxidase (GPX), glutathione transferase (GST), and glutathione reductase (GR) enzymes was observed, with maximum thresholds recorded on the third and second days, respectively. In the intestine a relevant increase in CAT and GST activity up to the second day and almost complete recovery by the end of the experiment was recorded, while for GR a continuous enhancement was apparent.     

Antioxidant Responses Versus DNA Damage and Lipid Peroxidation in Golden Grey Mullet Liver: A Field Study at Ria de Aveiro (Portugal)

The present work aimed to investigate golden grey mullet (Liza aurata) liver protection versus damage responses at a polluted coastal lagoon, Ria de Aveiro (Portugal), as a tool to evaluate the human impacts on environmental health at five critical sites in Ria de Aveiro (Portugal) in comparison to a reference site (Torreira; TOR). Protection was evaluated by measuring non-enzymatic [total glutathione (GSHt) and non-protein thiols (NPT)] and enzymatic [catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and glutathione reductase (GR)] antioxidant defenses. Damage was assessed as DNA integrity loss and lipid peroxidation (LPO). No significant differences were found between sites in terms of non-enzymatic defenses (GSHt and NPT). CAT did not display significant differences among sites. However, GPx at Barra (BAR, associated with naval traffic), Gafanha (GAF, harbor and dry-dock activities area), Laranjo (LAR, metal contaminated associated with chlor–alkali plant), and Vagos (VAG, contaminated by polycyclic aromatic hydrocarbons) was significantly lower than the reference site. GST was lower at GAF, Rio Novo do Príncipe (RIO, pulp mill effluent area), LAR, and VAG, whereas GR was lower at RIO. The loss of antioxidant defenses was paralleled by higher LPO levels only at GAF and VAG. However, no DNA integrity loss was found. Results highlight the importance of the adopted multibiomarkers as applied in the liver of L. aurata in coastal water pollution monitoring. The integration of liver antioxidant defense and damage responses can improve the aquatic contamination assessment.     

典型滤光剂纳米二氧化钛与2-羟基-4-甲氧基二苯甲酮联合染毒及其在鲫鱼体内蓄积和对肝抗氧化酶活力的影响

目的探讨典型滤光剂纳米二氧化钛与2-羟基-4-甲氧基二苯甲酮(BP3)联合染毒条件下,两者在鲫鱼不同组织的蓄积及对鲫鱼肝抗氧化酶活力的影响。方法将210尾健康12月龄雌性鲫鱼随机分成7组,分别为空白对照(曝气自来水)组、溶剂对照(0.01%甲醇)组和4、20μg/L BP3染毒组及100μg/L纳米二氧化钛染毒组以及4μg/L BP3+100μg/L纳米二氧化钛染毒组、20μg/L BP3+100μg/L纳米二氧化钛染毒组,每组30尾。采用半静态方式进行染毒,每天更换50%染毒溶液。分别在染毒7、14 d时,测定鲫鱼脑、肝脏、鳃、胆汁、肠、肌肉组织中纳米二氧化钛和BP3的含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GPx)的活力。结果空白对照组、溶剂对照组和纳米二氧化钛单独染毒组鲫鱼体内均未检出BP3。BP3单独染毒组中,BP3在鲫鱼肝和肠中的含量最高,分别为49.5~758.81 ng/g和40.12~890.32 ng/g;肌肉和胆汁的BP3含量最低,为4.38~24.72 ng/g。与相同浓度BP3单独染毒组比较,各浓度BP3+纳米二氧化钛联合染毒第7、14天时鲫鱼各组织中BP3的含量均较高,除肌肉和胆汁外,差异均有统计学意义(P0.05);且随着BP3和纳米二氧化钛染毒浓度的升高及染毒时间的延长,鲫鱼各组织中BP3的含量均呈上升趋势。空白对照组、溶剂对照组和BP3单独染毒组鲫鱼体内均未检出纳米二氧化钛。与溶剂对照组比较,第7、14天时20μg/L BP3染毒组和20μg/L BP3+100μg/L纳米二氧化钛染毒组鲫鱼肝脏SOD、CAT和GPx活力升高,差异均有统计学意义(P0.05);而空白对照组、4μg/L BP3染毒组、100μg/L纳米二氧化钛染毒组、4μg/L BP3+100μg/L纳米二氧化钛染毒组鲫鱼肝脏SOD、CAT和GPx活力均无明显变化。与相同浓度BP3单独染毒组比较,各浓度BP3+纳米二氧化钛染毒组鲫鱼肝脏SOD、CAT和GPx的活力升高,差异均有统计学意义(P0.05)。结论纳米二氧化钛的存在促进了BP3在鱼体鳃、肝、肠和脑中的蓄积,20μg/L的BP3会提高鲫鱼肝抗氧化酶活力,且共存的纳米二氧化钛促进鱼体肝脏抗氧化酶活力的升高。     

Effect of endosulfan on antioxidants of freshwater fish Channa punctatus Bloch: 1. Protection against lipid peroxidation in liver by copper preexposure

Effect of a single exposure of endosulfan (5 ppb) on catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), and reduced glutathione (GSH) of liver, kidney, and gill of a freshwater fish (Channa punctatus Bloch) were evaluated after 24 h of treatment. Endosulfan exposure resulted in a significant induction (p < 0.05–0.001) of GPx, GST activity, and GSH levels in all the organs. However, CAT activity was found to be significantly decreased (p < 0.01–0.001). Lipid peroxidation (LPO) values were also determined in liver, kidney, and gill and a significant increase in LPO values (p < 0.05–0.01) was observed in all the organs. We also investigated whether preexposure to low concentration of copper (10 ppb) for 4 weeks has any protective effect against endosulfan-induced oxidative damage. In copper-acclimatized endosulfan-exposed fish, a significant decrease in GPx (p < 0.001), GST (p < 0.05), GSH (p < 0.001) levels, and LPO (p < 0.01) was observed in the liver, whereas CAT activity was increased significantly (p < 0.001). However, kidney and gill did not show any significant alterations in antioxidant levels. The results of this study demonstrate that endosulfan induces peroxidative damage in liver, kidney, and gill in response to which levels of antioxidant were modulated. However, when fish preacclimatized to copper were exposed to endosulfan, protection against oxidative damage was observed only in the liver. It is proposed that measurement of antioxidants in fish tissues may prove to be useful in biomonitoring of exposure to aquatic pollutants. Received: 28 November 2000/Accepted: 14 April 2001     

Sub-lethal effects of profenofos on tissue-specific antioxidative responses in a Euryhyaline fish, Oreochromis mossambicus

The euryhaline fish, Oreochromis mossambicus was exposed to sub-lethal concentration (30 μg/L) of profenofos (PF) for 28 days and allowed to recover for 7 days. Responses were evaluated through antioxidant enzyme activities in various tissues of fish. Glutathione-S-transferase (GST) and superoxide dismutase (SOD) activities showed transient increases in gill, viscera and muscle, but decreased in brain. However, catalase (CAT) and glutathione reductase (GR) were inhibited in gill and viscera. Reduced glutathione (GSH) levels were depleted in all the tissues and a significant induction in lipid peroxidation (LPO) was observed. Significant recovery in all the studied parameters was noticed at the end of recuperation period. The enhanced LPO in the present study suggests that reactive oxygen species (ROS)-induced oxidative damage could be one of the main toxic effect of PF. The increased LPO and alterations in the antioxidant defense system can be used as biomarkers in the pesticide-contaminated aquatic streams.     

Effects of Aroclor 1254 on oxidative stress in developing Xenopus laevis tadpoles

Over the last decades, amphibians decline has been reported worldwide. Exposure to polychlorinated biphenyls (PCBs) is one of the possible causes in addition to climate changes, UV-radiation or habitat destruction. In the present study, we tested the hypothesis that PCBs could induce oxidative stress in young tadpoles. Developing Xenopus laevis were exposed from 2- to 5-d postfertilization (pf) to 0.1 or 1 mg/l of Aroclor 1254. Lipid peroxidation and antioxidant systems (SOD, CAT, GST, GPx, GR activities and t-GSH level) were investigated in whole organisms. Exposure to both concentrations did not impact on the survival and development whereas the average body weight decreased. Exposure to 1 mg/l of Aroclor 1254 induced a significant (p<0.05) increase of GST activity when compared to controls 0 and DMSO. The other antioxidant enzymes and LPO evaluation remained unchanged. Our results demonstrate that exposure of X. laevis tadpoles to environmental concentrations of Aroclor 1254 interfere with normal growth. They also highlight that very young X. laevis tadpoles express antioxidant systems.     

Acute toxicity of carbamazepine to juvenile rainbow trout (Oncorhynchus mykiss): effects on antioxidant responses, hematological parameters and hepatic EROD

Awareness of residual pharmaceutically active compounds (PhACs) in the aquatic environment is growing as investigations into these pollutants are increasing and analytical detection techniques are improving. However, the toxicological effects of PhACs have not been adequately researched. In this study, the toxic effects of carbamazepine (CBZ), an anticonvulsant drug commonly present in surface and groundwater, was studied in juvenile rainbow trout, Oncorhynchus mykiss, by acute semi-static bioassay. Bood parameters, liver xenobiotic-metabolizing response and tissue antioxidant status were evaluated. Compared to the control group, fish exposed to CBZ (96 h LC50) showed significantly higher Er, Hb, MCHC, monocytes, neutrophil granulocytes and plasma enzymes activity, and significantly lower MCV and lymphocytes. CF and HSI were not significantly different among groups such as hepatic EROD. SOD, CAT, GPx and GR activity was significantly higher in liver of experimental groups, but decreased significantly in brain and gill. In general, antioxidant enzyme activity in intestine and muscle was less evident than in liver. Oxidative stress indices (levels of LPO and CP) were significantly higher in gill and brain, despite a trend to increased values were manifested in the remaining tissues. In short, CBZ-induced stress responses in different tissues were reflected in the oxidant stress indices and hematological parameters. However, before those parameters are used as special biomarkers for monitoring residual pharmaceuticals in aquatic environment, more detailed experiments in laboratory need to be performed in the future.     

Time-Course Variations of DNA Damage and Biomarkers of Oxidative Stress in Tilapia (Oreochromis niloticus) Exposed to Effluents From a Swine Industry

DNA damage (Comet assay), lipoperoxidation levels (TBARS), and several biomarkers of oxidative stress such as catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione S-transferase (GST), and contents of reduced (GSH) and total (TG) glutathione were measured in liver and blood (Comet assay) of tilapia (Oreochromis niloticus) exposed for 7, 15, 30 (subchronic exposure), 60, and 90 days (chronic exposure) to two treatment lagoons of a swine-processing plant, the first an anaerobic lagoon and the second a final treatment lagoon. After the 15th day, TBARS increased in fish exposed to both lagoons, decreased on the 30th day, and on the 90th day remained similar to controls. Fish exposed subchronically and chronically to both effluents showed consistently greater DNA damage. The CAT and GPx activities showed similar profiles and were induced only during the first week and during the first and second months. GST activity was induced throughout the experimental period. On the other hand, GR activities showed inverted profiles, with progressively decreased activities in the liver of fish exposed to the anaerobic lagoon, and progressively increased activities in fish exposed to the final lagoon. GSH showed higher contents in liver after 60 and 90 days of exposure to the final lagoon. GSSG contents were higher in fish exposed to the final lagoon throughout the experimental period. After 15 days, tilapia exposed to both lagoons showed enhanced total glutathione contents. The hepatic antioxidant system and biomarkers of oxidative stress such as DNA fragmentation and TBARS contents of tilapia exposed to both lagoons presented biphasic profiles. These changes in the antioxidant status also indicate that the industrial treatment is not adequate to avoid damaging environmental effects.     

Oxidative stress biomarkers in Senegal sole, Solea senegalensis, to assess the impact of heavy metal pollution in a Huelva estuary (SW Spain): seasonal and spatial variation

The response of wild fish to heavy metals was studied in sole (Solea senegalensis) collected in 2004, 2005 and 2006 at three sampling sites from Huelva estuary (SW Spain), in the vicinity of a petrochemical and mining industry. Heavy metals As, Cd, Cu, Fe, Pb and Zn were analyzed in samples collected from sediment, water and tissue (liver) to examine their bioconcentration and effects in fish such as lipid peroxidation (LPO), catalase (CAT; EC 1.11.1.6), glutathione peroxidase (GPx; EC 1.8.1.7), glutathione S-transferase (GST; EC 2.5.1.18) and glutathione reductase (GR; EC 1.11.1.6) were also analyzed in the fish liver. The results showed different effects in sole from diverse locations with varying degrees of pollution. Significant differences in LPO, CAT and GR activities between control fish and fish from sampling sites were observed as well as seasonal differences for biomarkers. Significant correlations were established between some biomarkers and heavy metals concentrations in liver, sediment and water. This study indicates the usefulness of integrating a set of biomarkers to assess the effects of pollutants in aquatic environments under complex mix of pollutants and chronic pollution situation.     

Antioxidant Enzymes and Tissue Regeneration in Eurythoe complanata (Polychaeta: Amphinomidae) Exposed to Used Vehicle Crankcase Oil

Polychaetes, Eurythoe complanata, from the Gulf of Cariaco,Venezuela, were exposed to 0.3, 1.6, and 3.3% water-soluble fraction (WSF) of used crankcase oil during 15 and 21 days. The antioxidant enzymes glutathione peroxidase (GPX), glutathione reductase (GR), catalase (CAT), and glutathione-S-transferase (GST) were assayed in the body wall tissue. Furthermore, after chemical exposure, the polychaetes were cut into equal halves; then wound healing and the number of regenerated body segments were recorded periodically. GST activity was affected by all the experimental treatments, with activity increasing with WSF concentrations. GPx activity was altered for the contamination period. GR and CAT activities rose in response to increasing WSF concentrations, and were higher for long-term than for short-term exposures. The wound healing of the transected body regions was retarded by WSF exposure. WSF affected the tissue regeneration, which was almost abolished at 3.3% WSF. The exposure period did not affect the tissue-repairing responses. Alteration of GST in contaminated organisms suggested equivalent changes in detoxication of bioaccumulated organic contaminants. The variation of GR and CAT suggests induction of oxidative stress that could reduce the ability of WSF-exposed worms to repair damaged tissue.     

Tissue-Specific Antioxidant Responses in Pale Chub (Zacco platypus) Exposed to Copper and Benzo[a]pyrene

In this study, antioxidant responses including lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST), were evaluated in the liver, gill and muscle tissues of pale chub (Zacco platypus) exposed to copper (Cu) and benzo[a]pyrene (BaP). Cu exposure induced significant antioxidant responses in Z. platypus, particularly in the liver, whereas BaP exposure had a negligible effect. Following Cu exposure, both SOD and CAT activity increased in a concentration-dependent manner, showing significant correlations with malondialdehyde (MDA) levels as a measure of LPO (r = 0.646 and 0.663, respectively). SOD, CAT and GST mRNA levels were also enhanced following Cu exposure, except at 20 μg L^?1, although significant correlations with antioxidant enzyme activities were not found. The results of this study suggest that combined information on SOD and CAT activities together with LPO levels in the liver could be a useful indicator for assessing oxidative stress in freshwater fish.     

Wild juvenile Dicentrarchus labrax L. liver antioxidant and damage responses at Aveiro Lagoon,Portugal

The Aveiro Lagoon, at the north-western coast of Portugal, has been under considerable anthropogenic pressure for the last 5 decades. In order to perform an adequate survey of the effects induced by the contaminants in presence, wild juveniles Dicentrarchus labrax (sea bass) were selected. Thus, sea bass was captured at five sites: Torreira (TOR, as reference site), Gafanha (GAF), Rio Novo Príncipe (RIO), Laranjo (LAR) and Vagos (VAG) in autumn 2005. Liver defence responses such as catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), total glutathione (GSHt), total non-protein thiols (NP-SH) and metallothioneins (MT) were measured. Liver damage was determined as lipid peroxidation (LPO) and DNA integrity loss. RIO, LAR and VAG presented lower CAT, GR, GST activities and NP-SH and GSHt depletion in comparison to TOR. VAG and LAR showed higher GPx activity when compared to TOR. The highest MT level was found at GAF and VAG. The NP-SH and DNA integrity decreased at GAF compared to TOR. This field study demonstrated that not only antioxidant induction but also inhibitory responses must be considered as a signal of contamination.     

Role of selenium in mercury intoxication in mice

Studies were conducted to examine the effect of pre and post-treatment of selenium in mercury intoxication (20 micromole/ kg b.w. each given intraperitoneally) in mice in terms of lipid peroxidation (LPO), glutathione (GSH) content, activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and mercury concentration in liver, kidney and brain. No significant alteration was observed in all the organs examined after mercury or selenium treatment in LPO and GSH but administration of selenium (pre and post) resulted in an increase in the level of LPO and GSH. The activity of SOD was depleted in liver and kidney while that of GPx was lowered in liver of mercury exposed animals. Selenium administration resulted in restoration of the depletion of these enzymatic activities. The activity of CAT in liver and brain was enhanced both in mercury and selenium treated animals. Administration of selenium significantly arrested enhanced CAT activity. Kidney showed the highest mercury concentration among the organs examined. Administration of selenium resulted in further enhancement of mercury concentration in the tissues. An increase in selenium level in liver was observed after mercury treatment, which was also restored by mercury selenium co-administration. Our results indicate that the prooxidant effect of selenium was greater by its pretreatment.     

Accumulation and Elimination of Cadmium by the Nile Tilapia (Oreochromis niloticus) in differing Temperatures and Responses of Oxidative Stress Biomarkers

The aims of this study were to investigate the accumulation (15 days) and elimination (15 and 30 days) of cadmium (Cd) in the liver, gill, kidney and muscle of Oreochromis niloticus following exposures to different concentrations (1 and 2 mg/L) of Cd at different water temperatures (20, 25, 30 ^oC). Additionally, responses of oxidative stress biomarkers (superoxide dismutase, SOD; catalase CAT; glutathione peroxidase, GPx and malondialdehyde, MDA) of the liver were determined following Cd exposures. In accumulation period, Cd levels increased significantly in all the tissues at all temperatures and tissue accumulation order was kidney?>?liver?>?gill. All tissues, except the muscle, accumulated Cd in relation to exposure concentrations and water temperatures. There was no measurable level of Cd accumulation in the muscle, except in fish exposed to 2 mg Cd/L at 30 ^oC. Likewise, elimination of Cd from the tissues also increased in depends on periods and water temperatures. The order of Cd elimination from the tissues was gill?>?liver?>?kidney. The oxidative stress biomarkers also responded to both Cd exposure and temperature increases. The activities of antioxidant enzymes such as SOD, CAT, GPx and MDA levels in the liver increased in relation to increases in Cd concentrations and water temperatures.

     

Oxidative Stress Biomarkers in the Digestive Gland of Theba pisana Exposed to Heavy Metals

The in vivo toxic effects of sublethal treatment of 40 and 80% of 48-h LD₅₀ of topically applied trace metals [copper (Cu), lead (Pb), and zinc (Zn)] on oxidative stress biomarkers in the digestive gland of Theba pisana were examined. Oxidative individual perturbations were assessed by measuring nonenzymatic (glutathione; GSH) and enzymatic (catalase, CAT; glutathione peroxidase, GPx; and glutathione-S-transferase, GST) antioxidants in digestive gland of the snails. Lipid peroxidation (LPO) was also evaluated as a marker of cell damage. The results indicated that the copper ion was the most potent metal against this snail, followed by zinc and lead, for which the corresponding LD₅₀ values were 37.88, 261.72, and 652.55 μg/snail, respectively. The no-observed effect concentration (NOEC) values for Cu, Zn, and Pb were 10, 50, and 500 μg/snail, respectively, and the corresponding lowest-observed effect concentration (LOEC) values were 50, 100, and 1000 μg/snail. All trace metals resulted in a significant increase in the level of LPO, whereas a significant decline in the content of GSH was observed when compared with untreated controls. Treatment with both sublethal doses of the metals caused significant increase in CAT activity, except in the case of 40% LD₅₀ Zn and 80% LD₅₀ Cu, which exhibited no alteration in CAT when compared to control animals. GPx was significantly increased in snails exposed to 40% LD₅₀ Cu and Pb as well as 80% LD₅₀ Cu. However, an opposite effect was observed in snails exposed to 80% LD₅₀ Pb and in either 40 or 80% LD₅₀ of Zn-intoxicated animals. Treatment with Pb at two sublethal doses significantly increased GST activity, whereas treatment the animal with Cu caused significant inhibition in this enzyme. Snails exposed to 40% LD₅₀ Zn showed significant enhancement of GST, whereas snails exposed to 80% LD₅₀ showed ignificantly reduced GST activity. Biphasic responses were observed for CAT, GPx, and GST activities in snails exposed to Cu, Pb, and Zn, respectively. This study suggests that upregulation of the antioxidant enzyme activities, elevation of LPO, and the reduction in GSH content is related to oxidative stress in this species that could be useful as biomarkers for the evaluation of contaminated terrestrial ecosystems.     

Oxidative stress in pied flycatcher (Ficedula hypoleuca) nestlings from metal contaminated environments in northern Sweden

Metals have been shown to induce oxidative stress in animals. One of the most metal polluted terrestrial environments in Sweden is the surroundings of a sulfide ore smelter plant located in the northern part of the country. Pied flycatcher nestlings (Ficedula hypoleuca) that grew up close to the industry had accumulated amounts of arsenic, cadmium, mercury, lead, iron and zinc in their liver tissue. The aim of this study was to investigate if pied flycatcher nestlings in the pollution gradient of the industry were affected by oxidative stress using antioxidant molecules and enzyme activities. The antioxidant assays were also evaluated in search for useful biomarkers in pied flycatchers. This study indicated that nestlings in metal contaminated areas showed signs of oxidative stress evidenced by up regulated hepatic antioxidant defense given as increased glutathione reductase (GR) and catalase (CAT) activities and slightly but not significantly elevated lipid peroxidation and glutathione-S-transferase (GST) activities. Stepwise linear regression indicated that lipid peroxidation and CAT activities were influenced mostly by iron, but iron and lead influenced the CAT activity to a higher degree. Positive relationships were found between GST and lead as well as GR activities and cadmium. We conclude that GR, CAT, GST activities and lipid peroxidation levels may function as useful biomarkers for oxidative stress in free-living pied flycatcher nestlings exposed to metal contaminated environments.     

Biotransformation and antioxidant enzymes of Limnoperna fortunei detect site impact in watercourses of Córdoba,Argentina

The golden mussel Limnoperna fortunei was used as a biomonitor of environmental pollution in the Suquía River basin around Córdoba City (Argentina). The sampling sites along the river were chosen according to their increasing levels of pollutants (e.g. heavy metals) as well as biological oxygen demand (BOD) and chemical oxygen demand (COD). A water quality index (WQI) was constructed from the interaction of several normalized factors that affect the aquatic environment, such as the mentioned pollutants and physico-chemical characteristics of the sampling sites. Activity changes of biotransformation enzyme glutathione S-transferase (GST) and the antioxidant enzymes glutathione peroxidase (GPx), glutathione reductase (GR) and catalase (CAT), after exposure to pollutants, served as biomarkers. Membrane bound GST and antioxidant enzymes responded at the most polluted sampling site within 1 day showing increased activities lasting for 4 days. Further sampling was restricted due to no survival of the animals. Antioxidant enzymes GPx, GR and CAT were sensitive responding to the different pollution scenarios, showing good correlation to the chemical characterization.