Metal donation and apo-metalloenzyme activation by stable isotopically labeled metallothionein

Coupled HPLC-ICP-MS has been used to quantitatively study the effects of GSSG and GSH on the ability of metallothionein (MTII) to donate essential and non-essential metals to apo-carbonic anhydrase. Stable isotopically labeled (67)Zn(3)Cd(4) MTII was used to enable Zn donated from MTII to be differentiated from extraneous sources of Zn. Transfer of both (67)Zn and Cd from MTII to apo-carbonic anhydrase was noted in the absence of either GSSG or GSH. GSSG increased the initial transfer of both Zn and Cd. Thereafter, a gradual increase in the (67)Zn content at the expense of Cd was noted over 24-h indicating continued interaction and exchange between MTII and the enzyme commensurate with the relative preferences shown by the proteins for these two metals. Although GSH also increased transfer of (67)Zn from MT it reduced the simultaneous transfer of Cd to the enzyme thereby conferring protection against Cd induced activation.     

Synthesis and stability of phytochelatins induced by cadmium and lead in the marine diatom Phaeodactylum tricornutum.

The synthesis of phytochelatins (PC), intracellular metal-binding polypeptides characterized by a repeating sequence of gamma-glutamic acid- cysteine (gamma-Glu-Cys) pairs, has been studied in laboratory cultures of the marine diatom Phaeodactylum tricornutum exposed to Cd, Pb or Zn. Cd and Pb were able to induce PC of different degree of polymerization. The accumulation of the peptides follows a direct relationship with the metal exposure. No PC induction was observed in Zn-treated cultures, although the intracellular concentration of Zn increased during exposure. Both in short-term (7 h exposure, 10 microM Cd or Pb) and 3-day experiments (metal concentration less than 0.5 microM), the major fraction of total PC gamma-Glu-Cys subunits synthesized was polymerized as PC2 when cells were exposed to Pb, but as PC4 when cells were exposed to Cd. In short-term experiments about 50% of the gamma-Glu-Cys residues of the cellular pool of glutathione was quickly and almost quantitatively converted into PC. Recovery experiments, in which metal-stressed cells are suspended in a metal-free medium, showed a decrease of the PC pool and a concomitant increase of glutathione, suggesting a mechanism of degradation and release of metal-phytochelatin complexes.     

Municipal wastewater contamination in the Southern California Bight. Part II. Cytosolic distribution of contaminants and biochemical effects in fish livers

The objective of this study was to examine the cytosolic distribution of metals and oxygenated organic metabolites (MTBs), and biochemical effects, in livers of fish collected from both highly contaminated and less contaminated southern California coastal sites. Cytosolic extracts were separated by Sephadex G-75 column chromatography into high molecular weight (> 20 000 daltons) enzyme-containing (ENZ) pools, medium molecular weight (3000–20000 daltons) metallothionein- or metallothionein-like-containing (MT) pools, and low molecular weight (< 3000 daltons) glutathione-containing (GSH) pools.Concentrations of Cd, Cu and Zn were frequently lower in cytosolic pools of longspine combfish, yellowchin sculpin, and California tonguefish from highly contaminated Palos Verdes (PV) relative to those from less contaminated Santa Monica Bay (SMB) despite much higher concentrations of these metals in sediments at PV. Patterns of cytosolic metal distribution differed more between metals than between species or sampling locations. Most Cd, Cu and Zn occurred in the MT pools of these three species, with the exception of Zn in California tonguefish which occurred predominately in the ENZ pool. In all three species, ENZ-Cu showed positive slopes when regressed against total cytosolic Cu, while ENZ-Cd showed no significant slopes when regressed against total cytosolic Cd. Patterns for Zn were the least consistent among species, with higher ENZ-Zn slopes occurring in fish livers with lower cytosolic Zn concentrations.The largest portion of DDT and PCB oxygenated MTBs occurred in GSH pools of scorpionfish livers from PV or less contaminated Cortes Bank (CB). Concentrations of MTBs in ENZ- and MT-pools of CB scorpionfish livers showed positive slopes when regressed against total cytosolic- and GSH-MTBs.Positive slopes for regressions of ENZ-Cu, -Zn and -MTBs against total cytosolic concentrations are consistent with the model of an equilibrium-dependent exchange of these among cytosolic pools.The lower metal concentrations, higher glutathione concentrations, and higher catalase activities found in fish from PV relative to those from SMB are in accordance with effects known to result from exposure to organic contaminants.     

Inhibitory effects of divalent metal ions on liver microsomal 7-ethoxyresorufin O-deethylase (EROD) activity of leaping mullet

The purpose of the present study was to elucidate in vitro effects of Hg(2+), Zn(2+), Ni(2+) and Cd(2+) on cytochrome P4501A1 (CYP1A1) dependent EROD activities in leaping mullet liver microsomes. Fish captured from the most polluted part of Izmir Bay, had highly elevated EROD activities, and induced CYP1A1 protein levels as determined by Western blotting. Although all of the metal ions caused inhibition of the initial velocity of the reaction, Hg(2+) and Cd(2+) exhibited much higher inhibitory effect at lower concentrations and they were evidently more potent inhibitors than others. The inhibitor concentration giving 50% inhibition (IC(50) values) of Zn(2+), Ni(2+), Cd(2+) and Hg(2+) of initial EROD activity were 107, 16, 1.3 and 0.15 micromolar, respectively. Glutathione (GSH) at 0.5 mM final concentration, completely reversed Ni(2+) and Cd(2+) inhibition of EROD activity indicating the protective action of GSH.     

基于氧化逆境标志物的北部湾潮间带沉积物有机污染程度综合评价

利用综合生物标志物响应(IBR)指数对北部湾潮间带沉积环境中多氯联苯(PCBs)、石油烃(TPH)、壬基酚(NP) 和苯并芘(B[a]P)的综合污染水平进行评价。在9个站位采集波纹巴非蛤(Paphia undulata)和沉积物样品,测定沉积物和生物软组织中有机污染物含量,同时对鳃、内脏中与细胞防御系统有关的各7种标志物(包括还原型谷胱甘肽(GSH)、氧化型谷胱甘肽(GSSG)、谷胱甘肽过氧化物酶(GPx)、过氧化氢酶(CAT)等)进行分析。利用相关性分析法筛选出对1~2种有机污染物响应敏感的生物标志物共8种,分别为内脏中的GPx、GSH、GSSG、CAT和鳃中的GPx、GSH、GSSG、CAT。以筛选的8种生物标志物为基础, 9个站位IBR指数范围为0.27~1.48,其中站位S2(湛江市乐民镇码头)、站位S9(湛江市江洪码头)的IBR较小,显示污染程度最轻;站位S4(防城港西湾)、站位S3(钦州湾老人沙浅滩) IBR较高,显示生物体因有机污染产生氧化逆境。不同站位的IBR值与污染源分布、化学污染物分析结果基本一致,表明该方法可用于北部湾潮间带沉积物有机污染程度的综合评价。     

海水酸化和磺胺甲恶唑复合暴露对大马蹄螺抗氧化酶活性和脂质过氧化的影响

为探讨海水酸化和磺胺甲恶唑环境残留对珊瑚礁区生物的影响,本文以南海珊瑚礁区关键礁栖生物大马蹄螺（Trochus niloticus） 为研究对象,探究了两种环境胁迫因素对大马蹄螺的氧化胁迫作用。分别采用两个 pH 水平 （pH 8.1、 pH 7.6） 和三个磺胺甲恶唑浓度水平 （0 ng/L、100 ng/L 和 1 000 ng/L） 单独和复合暴露 28 天,测定其对大马蹄螺鳃组织的超氧化物歧化酶 （SOD）、过氧化氢酶 （CAT） 和谷胱甘肽巯基转移酶 （GST） 活性以及谷胱甘肽 （GSH） 含量和脂质过氧化水平 （LPO） 的影响。结果发现：海水酸化和磺胺甲恶唑单独暴露能够导致大马蹄螺鳃组织出现不同程度的氧化应激现象,表现为抗氧化酶 （CAT、SOD 和 GST） 活性和谷胱甘肽含量的升高。在复合暴露条件下,大马蹄螺鳃组织的抗氧化酶（CAT、SOD 和 GST） 活性和谷胱甘肽含量均受到不同程度的抑制,同时伴随着脂质过氧化水平的显著升高。这表明短期海水酸化和磺胺甲恶唑复合暴露可导致大马蹄螺鳃组织出现氧化损伤现象,进而可能对个体存活和种群繁衍造成负面影响。     

Heavy Metal Contents in Soft-Bottom Marine Macrophytes and Sediments Along the Mediterranean Coast of Spain

Abstract. Hg, Cd, Pb and Zn concentrations were determined in sediment and in tissues of five species of soft-bottom marine macrophytes ( Posidonia oceanica, Cymodocea nodosa, Zostera noltii, Ruppia cirrhosa and Caulerpa prolifera ) along the Spanish Mediterranean coast. Levels of metals were low in most of the sampling stations and similar to those found by other authors in uncontaminated zones. Certain locations, however, showed some degree of contamination (Cambrils, Almassora, Alacant, Mar Menor and El Portús). In Santa Pola we found high contents of metals in one sample of sediment due to the high proportion of the fine fraction (particules < 63µm) and organic matter, but not in the seagrass species. Mercury and zinc concentrations in the sediment are correlated to those in at least some anatomic fractions of Posidonia oceanica, Cymodocea nodosa and Caulerpa prolifera , suggesting that these species reflect the levels of these metals in the environment. Lead contents in the alga Caulerpa prolifera are also correlated to those in the sediment, while no significant correlations were obtained for cadmium. Among the species studied, Posidonia oceanica and Cymodocea nodosa seem to be better biomonitors than Caulerpa prolifera .     

菲和Cd2+单一及复合污染对毛蚶氧化胁迫效应的比较

采用半静态染毒实验研究了菲和Cd²⁺单一及复合污染下胁迫9 d和清水释放2 d过程中毛蚶体内活性氧(ROS)、谷胱甘肽(GSH)含量和谷胱甘肽硫转移酶(GST)活性的变化。结果表明,菲和Cd²⁺单独胁迫能诱导毛蚶体内ROS含量的增加及GSH含量、GST活性的降低,且随染毒浓度的增加,对各指标影响愈明显,存在剂量-效应关系。毛蚶体内GSH和GST的变化趋势具有一致性。菲和Cd²⁺复合污染对毛蚶体内的氧化胁迫效应整体大于二者单独污染。在清水释放阶段,单一及复合污染胁迫组各指标均能恢复至对照组水平。表明毛蚶体内抗氧化系统适合作为监测海洋多环芳烃和重金属复合污染的生物标志物。     

Bioaccumulation and depuration of Zn and Cd in mangrove oysters (Crassostrea rhizophorae, Guilding, 1828) transplanted to and from a contaminated tropical coastal lagoon

In order to study Zn and Cd accumulation and depuration, a set of oysters, Crassostrea rhizophorae, were transplanted to a metal contaminated coastal lagoon and another one was harvested there and transplanted to a non-polluted site. C. rhizophorae oysters and Perna perna mussels native from both sites were collected in order to monitor variability of metal concentration in resident populations. After three months exposure, oysters transplanted to the polluted site accumulated fourfold Zn (307-1319 microgg(-1)) without reaching the concentration level of resident oysters (9770 microgg(-1)). Cadmium concentrations had a slight but significant decrease during the same period (1.25-0.54 microgg(-1)). Oysters transplanted to the non-polluted site, showed threefold Zn depuration (6727-2404 microgg(-1)), while Cd had no significant variation (0.90-1.45 microgg(-1)). Results showed that transplanted oysters do not reach heavy metal concentrations in indigenous populations suggesting transplanted organisms would be better used to evaluate bioavailability instead of environmental concentrations.     

东海绿藻缘管浒苔营养成分分析及评价

分析了缘管浒苔(Enteromorphalinza)一般营养成分、18种氨基酸及矿物质的含量,并与藻类海产品海带、紫菜、羊栖菜、裙带菜进行营养学对照评价。结果表明,缘管浒苔中主要成分是多糖类和粗纤维,占藻体的63.9%。蛋白质含量27.0%,在几种海藻中较高。氨基酸组成均衡,必需氨基酸(EAA)占氨基酸总量(TAA)的38%,必需氨基酸与非必需氨基酸的比值(EAA/NEAA)为0.62;氨基酸价78,高于海带(47)和紫菜(54),限制性氨基酸均为赖氨酸;呈味氨基酸占总量的53%;谷氨酸、天氨酸、丙氨酸、亮氨酸等含量很高。脂肪量较低,为0.9%。矿物质和维生素含量丰富,其中Mg,Fe,Ca,K,Na,P,Zn等元素含量很高,尤其Mg,Fe,Zn高于其它海藻;钙磷比值合理,为1.9;尤其有害元素As含量远远低于同水域中4种海藻,为2.98mg/kg。因此缘管浒苔是一种低污染的高膳食纤维、高蛋白、低脂肪的富含维生素和矿物质的新型海洋食品。     

江苏－山东沿岸大型绿藻微观繁殖体时空分布特征研究

为研究暴发浒苔绿潮的黄海近岸水体中大型绿藻微观繁殖体时空分布和种群演替,以及绿潮对海域繁殖体群落结构的影响,本研究在江苏－山东沿岸设置4个站位,开展周年取样调查研究。通过室内培养和分子检测结合的方法,共鉴定出6种大型绿藻:缘管浒苔(Ulva linza)、浒苔(U. prolifera)、扁浒苔(U. compressa)、孔石莼(U. pertusa)、未命名种(Ulva sp.) 和盘苔(Blidingia sp.)。定量研究结果表明,各站位微观繁殖体丰度和种类组成具有明显时空变化特征,苏北浅滩与青岛近岸周年绿藻微观繁殖体丰度明显高于连云港燕尾港和日照岚山港站位;各站位丰度呈双峰型波动,春季到初夏达最高,秋季为次高峰,其他季节丰度较低。群落结构组成研究表明,苏北浅滩周年存在较高丰度的浒苔微观繁殖体(平均为77株/L),其中造成黄海大规模绿潮的“漂浮生态型”浒苔占绝对优势,年均占浒苔微观繁殖体总数的75.7%;青岛近岸微观繁殖体种类组成波动显著,在夏季大规模浒苔绿潮到达时,优势种从缘管浒苔转变成浒苔,其中,“漂浮生态型”浒苔微观繁殖体数量急剧上升,并在绿潮消退时快速消失。对比研究显示,苏北浅滩海域是浒苔微观繁殖体“栖息地”,对维持浒苔种群、造成绿潮连年暴发具有重要作用;青岛近岸微观繁殖体群落受到大规模漂浮浒苔的季节性扰动,其组成结构在绿潮暴发期发生显著变化。     

Cadmium,lead, copper,and zinc in Elminius modestus Darwin (Crustacea,Cirripedia) from Waitemata and Manukau Harbours,Auckland, New Zealand

Abstract

Concentrations of cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn) were measured in adult barnacles (Elminius modestus Darwin) from Waitemata and Manukau Harbours in the Auckland area, New Zealand. As in studies on sediments reported in the literature, it was possible to identify areas of likely anthropogenic influence, e.g., around the Auckland Harbour Bridge for Pb, Cu, and Zn. Groups of individuals with highest concentrations for these metals showed 19.8–23.8 mg Pb kg^?1, 198–266 mg Cu kg^?1, and 4460–6530 mg Zn kg^?1 (95% confidence limits, dry weight basis). Cd concentrations found for all barnacles from the Auckland area ranged from 0.8 to 3.1 mg kg^?1. Two samples from Omaha Beach, 60 km north of Auckland, were used as a reference. Accordingly, groups of individuals with lowest concentrations for Pb, Cu, and Zn could be allocated to this site using the Student‐Newman‐Keuls Multiple Range Test (0.5–1.3 mg Pb kg^?1, 8–10 mg Cu kg^?1, and 144–214 mg Zn kg^?1 ; 95% confidence limits). Only Cd concentrations were highest at Omaha Beach (8.6–12.1 mg Cd kg^?1 ). This result may have arisen from “naturally” increased bio‐availabilities of certain metals in mangrove systems which are reported in the literature. Generally, metal concentrations in barnacles from the Auckland Harbour area and from Omaha Beach were within the wider range for E. modestus as well as other barnacle species reported in the international literature.     

Effect of cadmium, copper and mercury on antioxidant enzyme activities and lipid peroxidation in the gills of the hydrothermal vent mussel Bathymodiolus azoricus

Metals are known to influence lipid peroxidation and oxidative status of marine organisms. Hydrothermal vent mussels Bathymodiolus azoricus live in deep-sea environments with anomalous conditions, including high metal concentrations. Although B. azoricus are aerobic organisms they possess abundant methano and thioautotrophic symbiotic bacteria in the gills. The enzymatic defences (superoxide dismutase (SOD), catalase (CAT), total glutathione peroxidase (Total GPx) and selenium-dependent glutathione peroxidase (Se-GPx)) and lipid peroxidation were determined in the gills of B. azoricus exposed to Cd (0.9 microM), Cu (0.4 microM) and Hg (0.1 microM) with different times of exposure. The experiments were performed in pressurized containers at 9+/-1 degrees C and 85 bars. Results show that vent mussels possess antioxidant enzymatic protection in the gills. Cd and Cu had an inhibitory effect in the enzymatic defence system, contrarily to Hg. These enzymatic systems are not completely understood in the B. azoricus, since reactive oxygen species might be produced through other processes than natural redox cycling, due to hydrogen sulphide and oxygen content present. Also the symbiotic bacteria may play an important contribution in the antioxidant protection of the gills.     

Effect of oil pollution on gluthione and relative enzyme in oyster(Saccostrea cuculiata)

The oysters ( Saccostrea cuculiata ) were collected from four stations around Xiamen Island (Lundu Port, Xinglin Bay, Tong" an Bay, Huangcuo). The relation between the level of petroleum hydrocarbon in whole tissue and the contents of glutathione (GSH), the activity of selenium-dependent glutathione peroxidase (Se-GPx) and glutathione S-transferase (GST) in digestive gland and gill were investigated. The results showed: (1) The contents of petroleum hydrocarbon in oyster collected from four stations (Lundu Port, Xinglin Bay, Tong'an Bay, Huangcuo) were 380.68, 112.34, 27.31, 20.37μg/g wet weight, respectively; (2) the activity of Se-GPx and GST in digestive gland was lower than that in gill, and the content of GSH seemed reversibly; (3) among the four stations, both Se-GPx and GST activity of digestive gland and gill in Saccostrea cuculiata sampled from the four stations showed a good correlation with whole tissue petroleum hydrocarbon, could be as biomarkers of sea oil pollution.     

Induction and Synthesis of Metallothionein in the Algae of Monostroma Angicava Kjellm, Entermorpha Linza(L.) J. AG and Ulva Pertusa Kjelim

The algae of M. andicava, E. linza and U. pertusa were induced for four days in artificialseawater colltaining 0.5 ppm of Cd~(2+), respectively. Then each of them was homogenizedand isolated. The final soluble fraction was chromatographed in a Sephadex G--75 column.     

经济海藻羊栖菜（Sargassum fusiforme）幼体对镉胁迫的响应特性

镉(Cd)是水生生态环境中常见的重金属污染物,通常会抑制植物的生长,减少生物量,对植物产生毒害作用。为了研究羊栖菜幼苗对海水中Cd胁迫的抗氧化响应特性,我们在天然海水和Cd加富(100 μmol·L^-1)海水两种不同的Cd浓度下培养羊栖菜幼体。实验结果表明:Cd加富胁迫显著抑制了羊栖菜幼苗生长,使藻体颜色变暗。此外,高Cd处理显著降低了羊栖菜中的色素含量,生长速率,过氧化物酶(POD)活性,脱氢抗坏血酸(DHA)含量和谷胱甘肽还原酶(GR)活性。相反,高Cd处理显著促进了藻体内的Cd元素积累、对Cd₂⁺吸收速率,并增加了其暗呼吸/净光合速率比值(R_d/P_n),抗坏血酸(Vc)含量,可溶性蛋白质(SP)含量,且还原型谷胱甘肽(GSH)以及羊栖菜的超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性均显著增加,但对丙二醛(MDA)的影响不显著。虽然羊栖菜幼苗增加了其抗氧化活性并促进AsA-GSH循环,以产生H₂O₂并维持健康的新陈代谢,但高Cd胁迫显著限制了幼苗的光合作用,降低了其光合色素,抑制了其生长,并使其藻体颜色发生变化。海水中高浓度的Cd对羊栖菜幼苗具有毒性作用,并且极大地增加了这种海藻的食用风险。     

长江口最大浑浊带潮周期内悬浮物中的重金属

In order to discuss the content distributions and fluxes of heavy metals in suspended matters during a tidal cycle in the turbidity maximum around the Changjiang(Yangtze) Estuary,the contents of heavy metals(Zn,Pb,Cd,Co and Ni) have been analyzed.During a tidal cycle,the average contents of heavy metals are in the order of ZnNiPbCo àCd.The average contents in ebb tide are generally higher than that in flood tide.However,at the inshore Sta.11,influenced by the contamination from the nearby waste treatment plant,the average contents of Zn and Ni in flood tide are higher than those in ebb tide and at the offshore Sta.10,the content of Cd in flood tide higher than that in ebb tide due to marine-derived materials.The five heavy metals,mainly terrigenous,are transported towards east-northeast,and settle down with suspended matters in the area between Sta.11 and Sta.10.Influenced by marine-derived materials,the flux value of Cd does not alter significantly with obviously changing in flux direction towards northwest.The source of heavy metals,the salinity of water and the concentration of suspended matters are the main factors controlling the content distributions of heavy metals during a tidal cycle.There is a positive correlation between the contents of heavy metals(Zn,Pb,Co and Ni) and the salinity of water,while the opposite correlation between the contents and the concentrations of suspended matters.Because of marine-derived materials,the content of Cd is not correlated with the concentration of suspended matters and the salinity of water.     

Bioaccumulation of trace metals in the amphipod Chaetogammarus marinus (Leach, 1815) from the Avon and Tamar estuaries (UK): comparison of two-compartment and hyperbolic toxicokinetic models

Bioaccumulation of Cd, Cr, Cu, Co, Pb, Ni and Zn was investigated in the eulittoral gammaridean amphipod Chaetogammarus marinus (Leach, 1815) from the Avon and Tamar estuaries (UK). The main goals were to provide information on accumulation strategies of the organisms tested and to verify toxicokinetic models as a predictive tool. The organisms accumulated metals upon exposure and it was possible to estimate significant model parameters of two-compartment and hyperbolic models, with the exception of Zn. Both types of models yielded significant model estimates in two independent toxicokinetic studies using gammarids from the Avon and Tamar estuaries, respectively. Kinetic BCFs at theoretical equilibrium were 58-102 for Cd, 95-215 for Cr, 400-963 for Cu, 38-59 for Co, 150-750 for Pb and 33-63 for Ni, and were in most cases distinctly lower than the range reported in the literature for other amphipods. To demonstrate the potential of toxicokinetic models as a predictive tool, attempts were made, further to verify time-dependent model data (Tamar) with independent experimental data (Avon). In this case only for Cd were both in good agreement, whilst for all other elements the models overestimated the measured values. The second approach was to verify time-dependent model data (Tamar) with measured values from an independent concentration-dependent uptake study (Tamar) or, alternatively, to estimate the model parameters simultaneously for both studies. A good agreement between observed and predicted values was obtained for all elements for the simultaneous two-compartment models. Only for Cd was a simultaneous estimation of the hyperbolic model more promising. A tentative estimation showed the following sequence of sensitivity of C. marinus to an increase of soluble metal exposure: 0.6 microg Cd l(-1), 1.7 microg Cr l(-1), 16 microg Cu l(-1), 3.5 microg Co l(-1), 0.8 microg Pb l(-1) and 7 microg Ni l(-1). Available information can be used to quantify a measure of agreement or disagreement between bioaccumulation in different amphipods. This can be regarded as an important step in the calibration of biomonitors which is necessary to assess the potential for bioaccumulation on a large geographical scale.     

Effect of cadmium, copper and mercury on antioxidant enzyme activities and lipid peroxidation in the gills of the hydrothermal vent mussel Bathymodiolus azoricus

Metals are known to influence lipid peroxidation and oxidative status of marine organisms. Hydrothermal vent mussels Bathymodiolus azoricus live in deep-sea environments with anomalous conditions, including high metal concentrations. Although B. azoricus are aerobic organisms they possess abundant methano and thioautotrophic symbiotic bacteria in the gills. The enzymatic defences (superoxide dismutase (SOD), catalase (CAT), total glutathione peroxidase (Total GPx) and selenium-dependent glutathione peroxidase (Se–GPx)) and lipid peroxidation were determined in the gills of B. azoricus exposed to Cd (0.9 μM), Cu (0.4 μM) and Hg (0.1 μM) with different times of exposure. The experiments were performed in pressurized containers at 9 ± 1 °C and 85 bars.Results show that vent mussels possess antioxidant enzymatic protection in the gills. Cd and Cu had an inhibitory effect in the enzymatic defence system, contrarily to Hg. These enzymatic systems are not completely understood in the B. azoricus, since reactive oxygen species might be produced through other processes than natural redox cycling, due to hydrogen sulphide and oxygen content present. Also the symbiotic bacteria may play an important contribution in the antioxidant protection of the gills.     

Effects of beta-naphthoflavone on hepatic biotransformation and glutathione biosynthesis in largemouth bass (Micropterus salmoides)

We are investigating the effects of in vivo exposure of prototypical enzyme inducing agents on hepatic biotransformation enzyme expression in largemouth bass (Micropterus salmoides), a predatory game fish found throughout the United States and Canada. The current study targeted those genes involved in biotransformation and oxidative stress that may be regulated by Ah-receptor-dependent pathways. Exposure of bass to beta-naphthoflavone (beta-NF, 66 mg/kg, i.p.) elicited a 7-9-fold increase in hepatic microsomal cytochrome P4501A-dependent ethoxyresorufin O-deethylase (EROD) activities, but did not affect cytosolic GST catalytic activities toward 1-chloro-2,4-dinitrobenzene (CDNB) or 5-androstene-3,17-dione (ADI). Glutathione S-transferase A (GST-A) mRNA expression exhibited a transient, but non-significant increase following exposure to beta-NF, and generally tracked the minimal changes observed in GST-CDNB activities. Expression of the mRNA encoding glutamate-cysteine ligase catalytic subunit (GCLC), the rate-limiting enzyme in glutathione (GSH) biosynthesis, was increased 1.7-fold by beta-NF. Changes in GCLC mRNA expression were paralleled by increases in intracellular GSH. In summary, largemouth bass hepatic CYP1A-dependent and GSH biosynthetic pathways, and to a lesser extent GST, are responsive to exposure to beta-NF.