Tissue-specific bioaccumulation and oxidative stress responses in juvenile Japanese flounder (Paralichthys olivaceus) exposed to mercury

To understand mercury (Hg) toxicity in marine fish, we measured Hg accumulation in juvenile Japanese flounder (Paralichthys olivaceus) and assessed the effects on growth and antioxidant responses. After Hg exposure (control, 5, 40, and 160 μg/L Hg) for 28 d, fish growth was significantly reduced. The accumulation of Hg in fish was dose-dependent and tissue-specific, with the maximum accumulation in kidney and liver, followed by gills, bone, and muscle. Different antioxidants responded differently to Hg exposure to cope with the induction of lipid peroxidation (LPO), which was also tissue-specific and dosedependent. As Hg concentration increased, superoxide dismutase (SOD) and catalase (CAT) activities increased significantly, whereas glutathione S-transferase (GST) activity and glutathione (GSH) levels decreased significantly in the gills. SOD and glutathione peroxidase (GPx) activities and the GSH level increased significantly in the liver. SOD activity and GSH levels increased significantly, but CAT activity decreased significantly with an increase in Hg concentration in the kidney. LPO was induced significantly by elevated Hg in the gills and kidney but was least affected in the liver. Therefore, oxidative stress biomarkers in gills were more sensitive than those in the liver and kidney to Hg exposure. Thus, the gills have potential as bioindicators for evaluating Hg toxicity in juvenile flounder.     

Chitosan oligosaccharide-Ca complex accelerates the depuration of cadmium from Chlamys ferrari

This study investigated the effect of a chitosan oligosaccharide-Ca complex (COS-Ca) on the depuration of cadmium (Cd) from Chlamys ferrari. After exposure to 0.5 mg L-1 CdCl2 for 3 or 7 d, the scallops were treated by COS-Ca prior to determina-tion of Cd, calcium (Ca) and zinc (Zn) contents, Cd distribution in organs, malondialdehyde (MDA) content and antioxidant variables. Results showed that COS-Ca reduced Cd content in the viscera of the scallops, with highest Cd depuration rate (47%) observed on day 3. The COS-Ca concentration substantially affected Cd depuration, and the exposure to 8.75 mg L-1 COS-Ca led to significantly higher Cd depuration rate compared with those of lower COS-Ca concentrations (1.75, 3.5, 5.25, and 7.00 mg L-1). Distribution analysis of Cd in scallop organs indicated that COS-Ca significantly reduced Cd content in the kidney throughout the 5-d experiment, as well as in the gill during the early stage of Cd depuration. In addition, COS-Ca treatment decreased glutathione peroxidase (GSH-Px) activity and MDA content while increasing superoxide dismutase (SOD) and catalase (CAT) activities on different days. Our work suggested COS-Ca complex treatment as an effective method for acceleration of Cd depuration from Cd-contaminated bivalves.     

Antioxidant response of ridgetail white prawn <Emphasis Type="Italic">Exopalaemon carinicauda</Emphasis> to harmful dinoflagellate <Emphasis Type="Italic">Prorocentrum minimum</Emphasis> exposure and its histological change

The dinoflagellate Prorocentrum minimum, one of the most widespread red tide causing species, affects marine aquaculture and ecosystems worldwide. In this study, ridgetail white prawn Exopalaemon carinicauda were exposed to P. minimum cells (5 × 10⁴ cells mL^?1) to investigate its harmful effects on the shrimp. Antioxidant activities and histological changes were used as indicators of health status of the shrimp. In 72 hours, the mortality of E. carinicauda was not affected, but its antioxidant response and histology were statistically different from those of control. Elevated superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities and depressed catalase (CAT) activity were observed in gill; while increased SOD, glutathione S-transferase (GST), CAT activities and modulated GPX activity were observed in hepatopancreas. Thus, antioxidant activities in gill and hepatopancreas seem to respond differentially to harmful alga exposure. Increased malondialdehyde (MDA) content in early a few hours indicates the damage of the antioxidant defense system. Although MDA content recovered to a low level thereafter, a series of histological abnormalities including accumulation or infiltration of hemocytes, tissue lesions and necrosis were discovered in gill and hepatopancreas. Exposure to P. minimum induced sublethal effects on E. carinicauda, including temporary oxidative damage and histological injury.     

Variations of antioxidant enzyme activity and malondialdehyde content in nemertean Cephalothrix hongkongiensis after exposure to heavy metals

The antioxidant enzyme activity and malondialdehyde (MDA) content of Cephalothrix hongkongiensis were studied to assess variations in the biochemical/physiological parameters of nemerteans under heavy metal stress. Worms were exposed to copper, zinc and cadmium solutions at different concentrations, and the activity of three antioxidant enzymes, catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX), and MDA content were measured. The results show that the activity of each enzyme changed immediately after exposure to heavy metals. CAT was invariably inhibited throughout the experimental period, while the SOD activity was significantly elevated by exposure to Cu²⁺ for 48 h, but then decreased. SOD was inhibited by Zn²⁺during the first 12 h of exposure, but activated when exposed for longer periods. Under Cd²⁺ stress, SOD activity decreased within 72 h. GPX activity varied greatly, being significantly increased by both Cu²⁺ and Zn²⁺, but significantly inhibited by Cd²⁺ in the first 12–24 h after exposure. MDA content increased on Cu²⁺ exposure, but normally decreased on Zn²⁺ exposure. MDA content followed an increase-decrease-increase pattern under Cd²⁺ stress. In conclusion, the antioxidant system of this nemertean is sensitive to heavy metals, and its CAT activity may be a potential biomarker for monitoring heavy metal levels in the environment.     

The influence of cadmium on the antioxidant enzyme activities in polychaete Perinereis aibuhitensis Grube (Annelida: Polychaeta)

The infaunal polychaete Perinereis aibuhitensis Grube, distributed widely along Asian coasts and estuaries, is considered a useful animal model in ecotoxicological tests and a promising candidate in biomonitoring programs. This paper deals with the activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidases (GSH-Px) in infaunal polychaete P. aibuhitensis exposed to a series of sublethal water-bound cadmium (Cd) concentrations (0, 0.34, 1.72, 3.44, 6.89, and 17.22 mg L⁻¹) under a short-term exposure (1–8 d). The results indicate that the SOD and GSH-Px activities in P. aibuhitensis are stimulated first and then renewed to the original level. The CAT activity of worms decreases at an earlier exposure time but increases to the control values at a later exposure time. Our study suggests that Cd can interfere with the antioxidant defense system of P. aibuhitensis. However, the changes in antioxidant enzyme activities for this species do not show the best promise as biomarkers in Cd biomonitoring of estuarine and coastal zones because weak or non-dose-effect relationships between the antioxidant enzymes activities and Cd levels are found.     

Effects of florfenicol exposure on growth,development and antioxidant capacity of flounder Paralichthys olivaceus larvae at different developmental stages

Antibiotics are widespread in various environmental media,and may pose a potential threat to aquatic ecosystems and non-target aquatic organisms.Florfenicol(FLO) is one of the most commonly used antibiotics in aquaculture,and extensively used to substitute chloramphenicol with its strong sterilization and low adverse ef fect.In this study,flounder Paralichthys olivaceus,an important economic fish species in seawater was used as an experimental subject.Five exposure concentrations of FLO(including environmentrelated concentrations) were set at 0,0.01,0.1,1,and 10 mg/L.Ef fects of FLO exposure for 168 h on growth and development,motor behavior,antioxidant enzyme activity,malondialdehyde(MDA) content,and thyroid hormone level of P.olivaceus larvae were studied in pre-larvae(1 dpf) and post-larvae(20 dpf).The results show that the short-term FLO exposure could promote the larvae growth to some degrees,but inhibit them as the exposure time prolonged.For pre-larvae,FLO at 0.01 mg/L could stimulate the motor nerve system and increase the swimming ability,but inhibited it at 1 mg/L.With the increasing dosage of FLO,the superoxide dismutase(SOD) and MDA contents were elevated,reaching the maximum in the 1 mg/L FLO group.The pre-larvae were more sensitive than the post-larvae to FLO in the environment,and the growth and immune resistance could be damaged with long exposure.Post-larvae were more tolerant to external pollutants,FLO at 1 mg/L could promote the motor behavior and reduce SOD and MDA contents.Therefore,FLO can be used as an antibiotic at a proper concentration but as a drug to prevent disease in a long-term way.     

TCDD对斑马鱼脂质过氧化作用的初步研究

将150条斑马鱼随机等分为5组:2,3,7,8-四氯代二苯并二噁英(TCDD)4个染毒组(染毒剂量分别为0.1μg/L、0.2μg/L、0.4μg/L和0.8μg/L)和空白对照组,水质接触染毒5d后,采用分光光度法测定其肝组织中丙二醛(MDA)含量和超氧化物歧化酶(SOD)、谷胱甘肽-S-转移酶(GST)的活力,研究TCDD对斑马鱼的脂质过氧化作用。结果发现,TCDD各剂量染毒组MDA含量均有所增加,其中0.2μg/L组差异显著(P<0.05),0.4μg/L和0.8μg/L剂量组差异极显著(P<0.01);各染毒组SOD活性均有所下降,其中0.2μg/L、0.4μg/L和0.8μg/L剂量组差异极显著(P<0.01);各染毒组GST活力均降低且差异极显著(P<0.01)。一定剂量的TCDD能引起MDA含量增加,使SOD和GST活力降低,对斑马鱼具有脂质过氧化作用。     

DISTRIBUTIVE TENDENCY OF ELEMENT CONCENTRATIONS IN LIMESTONE SOILS IN EASTERN CHINA

ＤＩＳＴＲＩＢＵＴＩＶＥＴＥＮＤＥＮＣＹＯＦＥＬＥＭＥＮＴＣＯＮＣＥＮＴＲＡＴＩＯＮＳＩＮＬＩＭＥＳＴＯＮＥＳＯＩＬＳＩＮＥＡＳＴＥＲＮＣＨＩＮＡＷｅｎＹａｎｍａｏ（温琰茂）；ＺｅｎｇＳｈｕｉｑｕａｎ（曾水泉）；ＰａｎＳｈｕｒｏｎｇ（潘树荣）；Ｌｕｏ...     

Effects of tributyltin （TBT） on enzyme activity and oxidative stress in hepatopancreas and hemolymph of small abalone, Haliotis diversicolor supertexta

We investigated the effect of tributyltin (TBT) exposure on the concentration of malondialdehyde (MDA) and the activity levels of the superoxide dismutase (SOD), catalase (CAT), and acid and alkaline phosphatase (ACP and AKP) enzymes in the small abalone, Haliotis diversicolor supertexta. We collected samples of the hepatopancreas and hemolymph 2, 6, 24, 48, 96, and 192 h after exposure to 0.35 μg (Sn)/L TBT. In the hepatopancreas, ACP activity was significantly higher in animals exposed to TBT 2, 24, and 96 h post-exposure compared with the control animals. AKP activity was also higher after 2 h, but SOD and CAT activity was unchanged. The concentration of MDA in the hemolymph was significantly higher than the control animals 2 and 6 h post-exposure. In the hemolymph of animals exposed to TBT, ACP activity was significantly lower than in the control animals 192 h post-exposure, whereas AKP activity was significantly lower 2 and 192 h post-exposure. Hemolymph SOD activity and levels of MDA were significantly lower than in the control animals 24 h after exposure but significantly higher after 96 h. Our results demonstrate that exposure to TBT cause rapid changes in ACP and AKP activity as well as altering the concentration of MDA in the hepatopancreas and hemolymph. SOD and CAT do not appear to be involved in the detoxification of TBT in the hepatopancreas of small abalone.     

Effects of benzo（a）pyrene exposure on the antioxidant enzyme activity of scallop Chlamysfarreri

Scallop Chlamys farreri was exposed to different concentrations of benzo(a)pyrene (BaP) (0.5 μg/L, 1.0 μg/L, 10.0 μg/L and 50.0 μg/L) for 30 days in seawater. The 7-ethoxyresorufin O-deethylase (EROD) activity was significantly induced, and increased with the increasing BaP concentration. The glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), Glutathione peroxidase (GPx) activities increased in short time at low concentration of BaP, and was significantly depressed at high concentr...     

Effect of dietary supplementation of vitamin C on growth,reactive oxygen species,and antioxidant enzyme activity of Apostichopus japonicus (Selenka) juveniles exposed to nitrite

Different amounts of vitamin C were added to diets fed to juveniles(2.5 ± 0.15 g) of sea cucumber Apostichopus japonic u s(Selenka) in an attempt to reduce the stress response of specimens exposed to nitrite stress. A commercial feed was used as the control diet and three experimental diets were made by supplementing 1 000, 1 500, or 2 000 mg vitamin C/kg diet to control diet separately in a 45-day experiment. Sea cucumbers were exposed to three different levels(0.5, 1.0, and 1.5 mg/L) of nitrite stress for 4, 8, and 12 h at four time intervals(0, 15, 30, and 45 d). Growth of the animals was recorded during the experiment. Reactive oxygen species(ROS)(i.e. hydroxyl free radical(-OH), malondialdehyde(MDA) and total antioxidant capacity(T-AOC)) and antioxidant enzyme activities(i.e., superoxide dismutase(SOD) and catalase(CAT)) were measured. Response surface methodology(RSM) was used to analyze the effect of multiple factors on ROS indices and enzyme activities. Weight gain(WG) and special growth rate(SGR) of vitamin C supplementation groups were significantly higher than those of control group( P 0.05). The levels of-OH and MDA increased under exposure time extending and nitrite concentration increasing, whereas T-AOC level decreased. SOD and CAT activities increased at 4 h and 8 h and decreased at 12 h. During the days in which the animal consumed experimental diets, the levels of-OH and MDA decreased and that of T-AOC increased. This result suggests that diets containing vitamin C could reduce the nitrite stress response in the animals and increase their antioxidant capacity. The multifactor regression equation of growth performance, ROS indices, and duration of feeding results suggest that vitamin C supplementation of 1 400–2 000 mg/kg diet for 29–35 days could reduce effectively the effects of nitrite exposure.     

Effect of benzo[a]pyrene on detoxification and the activity of antioxidant enzymes of marine microalgae

The objective of this study was to examine the effect of benzo[a]pyrene(Ba P) on the detoxification and antioxidant systems of two microalgae,Isochrysis zhanjiangensis and Platymonas subcordiformis.In our study,these two algae were exposed to Ba P for 4 days at three different concentrations including 0.5 μg~(L-1)(low),3 μg~(L-1)(mid) and 18 μg~(L-1)(high).The activity of detoxification enzymes,ethoxyresorufin O-deethylase(EROD) and glutathione S-transferase(GST) increased in P.subcordiformis in all Ba P-treated groups.In I.zhanjiangensis,the activity of these two enzymes increased at the beginning of exposure,and then decreased in the groups treated with mid-and high Ba P.The activity of antioxidant enzyme superoxide dismutase(SOD) increased in I.zhanjiangensis in all Ba P-treated groups,and then decreased in high Ba P-treated group,while no significant change was observed in P.subcordiformis.The activity of antioxidant enzyme catalase(CAT) increased in I.zhanjiangensis and P.subcordiformis in all Ba Ptreated groups.The content of malondialdehyde(MDA) in Isochrysis zhanjiangensis increased first,and then decreased in high Ba P-treated group,while no change occurred in P.subcordiformis.These results demonstrated that Ba P significantly influenced the activity of detoxifying and antioxidant enzymes in microalgae.The metabolic related enzymes(EROD,GST and CAT) may serve as sensitive biomarkers of measuring the contamination level of Ba P in marine water.     

Growth inhibition and oxidative stress in two species of marine diatoms exposed to 1-phenylethanol

1-phenylethanol(1-PEA)is a flavor extensively used in the production of co smetics,beverages,and food.The release of 1-PEA into coastal environments has aroused great concern.However,its potential effects on marine organisms are still unknown.In order to provide a better understanding of the ecological risks of 1-PEA in marine environments,this study determined the toxic effects of 1-PEA on two marine diatoms(Phaeodactylum tricornutum and Skeletonema costatum).The diatoms were grown in culture medium containing different concentrations of 1-PEA for 96 h.The contents of chlorophyll a,chlorophyll c,glutathione(GSH),malondialdehyde(MDA),and the activities of superoxide dismutase(SOD),catalase(CAT)and glutathione peroxidase(GPx),were measured at the end of the exposure period.1-PEA was shown to significantly inhibit the growth of diatoms,with 96-h EC_(50) values of 257.14 mg/L and 126.46 mg/L in P.tricornutum and S.costatum,respectively.In P.tricornutum,the levels of SOD,CAT,GPx,GSH,and MDA were stimulated only when 1-PEA concentrations were close to or greater than the 96-h EC_(50)value.However,in S.costatum,the activities of SOD and CAT,and the syntheses of two chlorophylls were inhibited even at an exposure concentration below the 96-h EC_(50) value.Taken together,these findings indicate a potential ecological risk by discharging 1-PEA into coastal areas and its species-specific toxic effects on marine organisms.     

Enzyme responses and lipid peroxidation in gills and hepatopancreas of clam Mactra vereformis, following cadmium exposure

To assess the toxicity of heavy metal pollution to marine intertidal shellfish, enzymatic responses and lipid peroxidation were investigated in the clam Mactra vereformis exposed to cadmium under laboratory conditions. Three antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPx), two immune defense enzymes (acid phosphatase, ACP; alkaline phosphatase, ALP), and one lipid peroxidation product (malondialdehyde, MDA) were measured in the gills and the hepatopancreas of the ...     

Salicylic acid and heat acclimation pretreatment protects Laminaria japonica sporophyte (Phaeophyceae) from heat stress

Possible mediatory roles of heat acclimation and salicylic acid in protecting the sporophyte of marine macroalga Laminaria japonica (Phaeophyceae) from heat stress were studied. Heat stress resulted in oxidative injury in the kelp blades. Under heat stress significant accumulation of hydrogen peroxide (H₂O₂) and malonaldehyde (MDA), a membrane lipid peroxidation product, and a drastic decrease in chlorophyll a content were recorded. Activity of the enzymatic antioxidant system was drastically affected by heat stress. The activity of superoxide dismutase (SOD) was significantly increased while peroxidase (POD), catalase (CAT) and glutathione peroxidase (GPX) were greatly inhibited and, simultaneously, phenylalanine ammonia-lyase was activated while polyphenol oxidase (PPO) was inhibited. Both heat acclimation pretreatment and exogenous application of salicylic acid alleviated oxidative damage in kelp blades. Blades receiving heat acclimation pretreatment and exogenous salicylic acid prior to heat stress exhibited a reduced increase in H₂O₂ and MDA content, and a lower reduction in chlorophyll a content. Pretreatment with heat acclimation and salicylic acid elevated activities of SOD, POD, CAT, GPX and PPO. Considering these results collectively, we speculate that the inhibition of antioxidant enzymes is a possible cause of the heat-stress-induced oxidative stress in L. japonica, and enhanced thermotolerance may be associated, at least in part, with the elevated activity of the enzymatic antioxidant system.     

山东省黄河下游地区浅层地下水地球化学特征与环境质量评价

浅层地下水调查是山东省黄河下游流域生态地球化学调查项目中的一项工作内容。调查是按每16 km2采集1件浅层地下水样品的密度,分析测试As,Ba,Be,Ca,Cd,Co,Cu,Fe,Hg,Pb,Se,Zn,F-,Cl-,Cr6 ,NO2-,COD,pH等33项指标;通过对这些指标在浅层地下水中的背景变化规律研究认为:调查区内浅层地下水中各指标含量起伏变化大,局部富集程度高,特别是As,Fe,K,La,Sb,Sn,Zn,Cl-,NO2-等指标的变异系数均>3.0,说明这些指标在浅层地下水中分布极不均匀,虽然背景含量较低,但在局部地段会形成高含量区,影响浅层地下水质量。选择As,Ba,Be,Cd,Co,Cu,Fe,Hg,Mn,Mo,Ni,Pb,Se,Zn,F-,Cl-,Cr6 ,NO2-,COD,pH等20项指标,按《地下水环境质量标准》中的要求,对浅层地下水环境质量进行的单项组分和综合评价结果显示,达到较好级以上者不足9%,而较差和极差级者达90%以上,表明调查区内浅层地下水环境污染状况较为严重。     

Studies on the effects on growth and antioxidant responses of two marine microalgal species to uniconazole

Uniconazole, as a plant growth retardant, can enhance stress tolerance in plants, possibly because of improved antioxidation defense mechanisms with higher activities of superoxide dismutase(SOD) and peroxidase(POD) enzymes that retard lipid peroxidation and membrane deterioration. These years much attention has been focused on the responses of antioxidant system in plants to uniconazole stress, but such studies on aquatic organism are very few. Moreover, no information is available on growth and antioxidant response in marine microalgae to uniconazole. In this paper, the growth and antioxidant responses of two marine microalgal species, Platymonas helgolandica and Pavlova viridis, at six uniconazole concentrations(0-15 mg L-1) were investigated. The results demonstrated that 3 mg L-1 uniconazole could increase significantly chlorophyll a and carbohydrate contents of P. helgolandica(P 0.05). Higher concentrations(≥12 mg L-1) of uniconazole could inhibit significantly the growth, dry weight, chlorophyll-a and carbohydrate contents of P. helgolandica and P. viridis(P 0.05). Uniconazole caused a significant increase in lipid peroxidation production(MDA) at higher concentrations(≥ 9 mg L-1). The activities of antioxidant enzymes, superoxide dismutase(SOD) and catalase(CAT) were enhanced remarkably at low concentrations of uniconazole. However, significant reduction of SOD and CAT activities was observed at higher concentrations of uniconazole.     

温度和盐度对军曹鱼幼鱼生长与抗氧化酶活性的影响

在实验室条件下,采用两因素交叉分组的方法,初步研究了环境因子(温度和盐度)对军曹鱼幼鱼肌肉抗氧化酶比活力的影响。温度设3个水平(26、29、32),盐度设4个水平(11、19、27、35),两个因素按其各自水平共产生12种组合。军曹鱼幼鱼在玻璃钢水槽内养殖20d后取样测定超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GPX)的比活力。结果表明:盐度因子诱导了军曹鱼的抗氧化应激反应,抗氧化酶活力随盐度降低而升高,SOD、CAT和GPX比活力分别从35时的17.74±3.38、19.44±2.66和13.70±2.99U/mg上升到11时的30.14±1.76、35.63±10.59和17.44±4.32U/mg;温度、盐度及因素间的交互作用对SOD和CAT比活力有显著影响(P<0.05);温度对GPX比活力无显著影响(P>0.05),而盐度及因素间的交互作用对GPX比活力影响显著(P<0.05)。     

Expression profiles of two small heat shock proteins and antioxidant enzyme activity in Mytilus galloprovincialis exposed to cadmium at environmentally relevant concentrations

Small heat shock proteins encompass a widespread but diverse class of proteins,which play key roles in protecting organisms from various stressors.In the present study,the full-length cDNAs of two small heat shock proteins(MgsHSP22 and MgsHSP24.1)were cloned from Mytilus galloprovincialis,which encoded peptides of 181 and 247 amino acids,respectively.Both MgsHSP22 and MgsHSP24.1 were detected in all tissues examined by real-time PCR,with the highest expression being observed in muscle and gonad tissues.The real-time PCR results revealed that Cd signifi cantly inhibited MgsHSP22 expression at 24 h and MgsHSP24.1 at 24 and 48 h under 5 μg/L Cd 2 + exposure.MgsHSP24.1 expression was also signifi cantly inhibited after 50 μg/L Cd 2+ exposure for 48 h.With regard to antioxidant enzymes,increased GPx and CAT activity were detected under Cd 2+ stress(5 and 50 μg/L),while no signifi cant difference in SOD activity was observed throughout the experiment.Overall,both MgsHsps and antioxidant enzymes revealed their potential as Cd stress biomarkers in M.galloprovincialis.