Characterization of hepatic and extrahepatic glutathione S-transferases in rainbow trout (Oncorhynchus mykiss) and their induction by 3,3′,4,4′-tetrachlorobiphenyl

Liver, kidney, gill and olfactory epithelium cytosolic fractions of rainbow trout (Oncorhynchus mykiss) were examined for glutathione S-transferase (GST) contents. Proteins retained on a glutathione (GSH)-affinity matrix were separated as monomers by reversed-phase HPLC and characterized by immunoblotting, mass spectrometry and partial amino acid sequence. For each organ concerned, a specific pattern of these proteins was determined and appeared similar for liver and kidney on one hand, and for gill and olfactory epithelium on the other hand. It was confirmed that the prominent hepatic GST is a class enzyme, also constitutively expressed as a major isoform in the four organs studied. Moreover, a class variant and two new class GST subunits were characterized in minor fractions. An unknown protein, which was found major in gills and olfactory epithelium, exhibited some characteristics of class GSTs. Occurrence of possible GSH-adduct formation observed on two distinct monomers in specific experimental conditions is discussed. These results and methods were used to investigate the effect of 3,3,4,4-tetrachlorobiphenyl (TCB), a polychlorinated biphenyl (PCB), on GST expression in trout liver. From HPLC-profiling, significant co-induction of the major class and the two minor class GST subunits was observed in trout after waterborne exposure to TCB which was followed by a slight increase in 1-chloro-2,4-dinitrobenzene (CDNB) activity. The present work allows qualitative evaluation of the specific detoxification potential of rainbow trout. The use of HPLC-profiling of GSTs as a possible tool for the biomonitoring of polluted aquatic environment is suggested.     

Presence and distribution of PAHs,PCBs and DDE in feed and sediments under salmon aquaculture cages in the Bay of Fundy,New Brunswick,Canada

• 1. Wastes from feed and faeces can result in the deposition of contaminants in sediments around aquaculture sites. Five types of feed pellet, a commercial fish oil and 76 sediment samples collected under and up to 100 m away from salmon aquaculture cages in the south‐western Bay of Fundy between 1998 and 2000 were analysed for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and chlorinated pesticides.
• 2. Five alkylated naphthalenes (aNAs) were consistently detected in fish oil (116–180 ng g^?1, per aNA), in pellets (25–51 ng g^?1, dry weight, per aNA), and sediments (<1–45 ng g^?1, dry weight, per aNA). Other PAHs were detected at variable levels in feed or in sediments.
• 3. IUPAC congener 153 (a PCB) and p,p′‐dichlorodiphenyldichloroethylene (p,p′‐DDE) were detected more frequently than other chlorinated targets in oil (108 ng g^?1 and 176 ng g^?1 respectively), feed (<1–14 ng g^?1 and 1.7–28.2 ng g^?1 respectively) and sediments (<0.08–3 ng g^?1 and <0.5–7 ng g^?1 respectively).
• 4. Trends were observed during the first year of sediment sampling (1998), with higher organic carbon, PCBs and p,p′‐DDE levels below the cages than 50 m away. The PAHs other than aNA showed an opposite trend with distance. In 1999, levels of p,p′‐DDE and PCBs were somewhat reduced under the cages, but were detected up to 100 m away from the cages.
• 5. Levels of aNA tended to be higher at some sites in 1999 relative to 1998, reflecting variability in feed and/or differential transport or degradation of contaminants relative to the environmental background. When detected, mean levels of PCBs and DDE were 2–10 times lower in 2000 than in 1999, and PAHs were 30–40% lower in 2000 than in 1999.
• 6. Interpretation of the results is done cautiously, since the exact locations of the sites sampled is only known to an intermediate facilitating the work between farmers and scientists. Levels of contaminants are compared with international results, interpreted relative to potential toxicity, uptake from feed, from deposited sediments, and in the framework of an aquaculture decision‐support system published recently.

Copyright © 2005 John Wiley & Sons, Ltd.     

Endocrine stress response and abnormal development in carp (Cyprinus carpio) larvae after exposure of the embryos to PCB 126

To investigate whether PCB 126 exposure duringembryonic development induces an endocrine stressresponse in larval carp, eggs were exposed,containing 0.01% ethanol (vehicle-control), 10^-11,immediately after fertilization, for 48 h to water10^-10 or 10^-9 mol l^-1 PCB in 0.01% ethanol. Eggsincubated in water served as controls. After transferto PCB-free water, mortality, the incidence ofyolk-sac and pe-ricardial oedema, wet and dry weight,rate of skin pigmentation, and whole-body contents ofthe stress hormones ACTH, -MSH and cortisol weredetermined at 48, 96, 144, 168, 192 and 216 hpost-fertilization. Except for the dry weight, allparameters of animals exposed to 10^-10 and 10^-9 moll^-1 PCB increased in a concentration-related manner.However, these changes became evident only at 144 hpost-fertilization, i.e. after resorption of theyolk-sac. Swelling of the yolk sac and pericardiumoccurred, and whole-body ACTH, -MSH and cortisollevels increased. Although animals exposed to 10^-10and 10^-9 mol l^-1 PCB displayed stable but elevatedwhole-body ACTH and -MSH levels until 216 h,whole-body cortisol concentrations gradually decreasedfrom 168 h post-fertilization, and were significantlybelow control values at 216 h post-fertilization.Exposure of the carp embryos to 10^-11 mol l^-1 PCB only increased whole-body -MSH levels. Increased whole-body ACTH and cortisol levels indicate that PCBinduces a stress response in carp larvae, possiblymediated by a disturbed hydromineral balance (oedema).We further suggest that the PCB-stimulated bodypigmentation is mediated by a stimulation of -MSHsecretion.     

Polychlorinated biphenyls (PCBs) in bulk soil and particle size separates of soils in a rural community

In a rural community (Stephanskirchen, Southern Germany) situated near a waste incineration plant six A horizons were sampled to determine 14 polychlorinated biphenyls (PCBs) in bulk soil and particle size separates (clay, silt, fine and coarse sand) and to test the suitability of alkaline saponification for PCB extraction. The PCB concentrations were higher in alkaline saponification extracts than in Soxhlet extracts. However, the extraction efficiency of up to fourfold chlorinated PCBs was lower and more than sevenfold chlorinated PCBs were destroyed. Nevertheless, alkaline saponification was suitable to determine the indicator congeners 28, 52, 101, 138, 152, and 180. The sum of the PCB concentrations ranged from 8.4 to 59.5 μg kg^?1 which was as high as in soils of big cities. However, the concentrations did not reach the threshold value for agricultural purposes of 200 μg kg^?1 as proposed in literature for the sum of the six indicator congeners. The hexachlorinated PCBs 138 and 153 were the most abundant (together > 50% in all samples) whereas PCB 1 could not be detected in any sample. On the average, PCB concentrations increased as particle size decreased. When normalized to C_org, however, the fine sand fraction had the highest PCB concentrations. A slight decrease of lower chlorinated PCBs as particle size decreased indicated an increasing state of degradation. The PCB compositions in the emissions of a comparable waste incineration plant (Bamberg, Bavaria) and in Stephanskirchen soils differed markedly. Therefore, we did not get any indications that waste incineration was a main source of PCBs in the examined soils. Instead, higher chlorinated technical PCB mixtures such as Clophen A 60 or Aroclor 1260 may be the most important sources.     

通用调理剂对土壤PCB28降解的效果及影响因素研究

[目的]明确施用通用调理剂对土壤PCB28降解的影响。[方法]土壤添加2 mg/kg PCB28后,根据不同浓度通用调理剂、有机肥和含水率等设置12个处理,开展培养试验,并于培养0、14、21、28 d采集土样分析PCB28浓度。[结果]施用调理剂能够促进土壤PCB28的降解,其降解率为48.6%,施用有机肥可以继续促进PCB28的降解率至59.8%,并且提高含水率能够进一步提高PCB28的降解率至67.9%。[结论]施用0.4 mg/g调理剂、0.7 mg/g有机肥和提高土壤含水率能够显著提高土壤PCB28的降解率。     

翡翠贻贝肾CYP4基因表达受多氯联苯影响的研究

[目的]了解多氯联苯(PCB)对翡翠贻贝肾中细胞色素P450第4亚族(CYP4)基因表达的影响。[方法]从野生翡翠贻贝cDNA中扩增得到了翡翠贻贝CYP4基因和β-actin基因的部分cDNA序列,并根据所得序列设计定量PCR引物,以β-actin为内参基因,以SYBRGreenI为荧光染料,利用荧光定量PCR对经PCB暴露处理后的翡翠贻贝肾中CYP4基因表达水平进行定量测定。[结果]PCB暴露处理对翡翠贻贝肾中CYP4基因的表达有明显的诱导作用,并且这种诱导作用对CYP4表达水平的影响与PCB暴露处理的时间以及浓度有相关性。[结论]该研究为CYP4基因作为生物大分子标记物在环境监测领域的应用提供了分子生物学水平的支持,同时为海水双壳类动物体内CYP4基因功能的研究提供了有益线索。     

多氯联苯(PCB153)对湛江叉鞭金藻生理生态和超微结构的影响

为研究多氯联苯对海洋微藻的生理生态毒性,以湛江叉鞭金藻(Dicrateria zhanjiangensis)为研究对象,进行7 d的六氯联苯(PCB153)胁迫实验,比较其生长、光合色素含量、谷胱甘肽S-转移酶(GST)、超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量以及藻细胞超微结构的变化情况。结果显示,PCB153胁迫对湛江叉鞭金藻的生长、光合色素含量及抗氧化和解毒相关指标均有显著影响(P<0.05)。随着PCB153浓度的增大,其对湛江叉鞭金藻生长抑制作用不断增大,250 μg/L胁迫组藻细胞在第5天全部死亡。PCB153胁迫后,湛江叉鞭金藻叶绿素a、叶绿素c、类胡萝卜素和总光合色素均显著下降(P<0.05),且随着PCB153浓度的增加,各实验组光合色素含量下降比例增大。PCB153胁迫后,各胁迫组藻细胞MDA含量显著增加;低浓度PCB153 (< 25 μg/L)胁迫显著诱导SOD和GST活性的提高;而高浓度PCB153(> 25 μg/L)胁迫则显著抑制2种酶活性。短期低浓度PCB153胁迫会改变金藻细胞超微结构,使细胞器形态改变、聚缩;高浓度PCB153胁迫则会直接破坏细胞膜的完整性,使细胞破裂,导致细胞自溶死亡。研究表明,PCB153抑制叉鞭金藻的生长和光合色素合成,低浓度PCB153激活抗氧化和解毒系统,提高其自我保护水平,高浓度PCB153加剧脂质过氧化,破坏抗氧化和解毒系统正常功能,导致细胞破裂死亡。     

多氯联苯（PCB_（1254））对栉孔扇贝渗透调节的影响

为了给我国沿海有机物污染地区栉孔扇贝健康养殖提供监测依据,研究了多氯联苯（PCB1254）对栉孔扇贝血淋巴渗透压和鳃丝Na＋-K＋-ATPase活力的影响。结果表明：PCB1254浓度为1.0μg·L-1以上处理组栉孔扇贝血淋巴渗透压变化明显,其中1.0μg·L-1处理组扇贝血淋巴渗透压显著上升,而10.0和50.0μg·L-1处理组栉孔扇贝的血淋巴渗透压呈先上升后下降的趋势,最后与海水对照组相近;低浓度（0.5和1.0μg·L-1）处理组扇贝鳃丝Na＋-K＋-ATPase活力明显被激活,而高浓度（10.0和50.0μg·L-1）处理组Na＋-K＋-ATPase活力在测定的每个时间点明显被抑制。因此认为多氯联苯影响下,机体所产生的有害代谢物可导致栉孔扇贝应激性反应和细胞膜结构的改变,导致血淋巴渗透压和Na＋-K＋-ATPase活力的变化,而且Na＋-K＋-AT-Pase活力变化与PCB1254浓度呈现一定相关性,能反映机体受PCB1254影响的程度,可以作为评价PCB1254污染的生理学指标。     

Media Coverage of PCB Contamination of Farmed Salmon: The Response of U.S. Import Demand

This article evaluates the effects of extensive media coverage of a study published in 2004 regarding the presence of polychlorinated biphenyls (PCBs) and other organic contaminates in farmed salmon on U.S. import demand for fresh farmed salmon. The study indicated that levels of PCBs differed according to source, with highest PCB levels found in salmon from Northern Europe and lowest in those from Chile. Using a newspaper article index as a proxy for information, a two-stage demand model is estimated. In the first stage, total U.S. import demand for fresh farmed salmon is estimated to determine the overall effect of the information, while the second stage determines if there were any significant changes in market shares of source countries. Results indicate that imports declined by approximately one-third of what would have been in the absence of the PCB media stories during 2004–2006, and that some changes in exporters’ market shares occurred. Health implications for U.S. seafood consumers are discussed.     

Analysis and Countermeasures of the Power Noise During High Frequency PCB Design

The paper analyses many forms of power supply noise interference in the high frequency PCB and the relevant reasons. Combining several formulas with the relevant engineering experience, the authors bring forward a lot of related means; finally conclude the chief principle that controlling power noise should abide by.