Evaluation of toxicity in tributaries of the Mersey estuary using the isopod Asellus aquaticus (L.)

Increasing numbers of industrial, agricultural and natural chemicals are present in sewage effluent and are known to elicit toxic effects in laboratory exposures, but little is known of their combined sub-lethal effect in the field. In this study, a combination of esterase activity and ventilation rate assays was performed to determine the neurological and physiological function of the freshwater crustacean Asellus aquaticus (L.) at sites above and below a sewage treatment works (STW). Cholinesterase and carboxylesterase activities were significantly inhibited (n=8, P<0.05) and ventilation rates increased (n=8, P=0.0001) in A. aquaticus at STW sites compared to those from reference sites, indicating a decrease in neurological and physiological function. The ecological relevance of these findings for the population dynamics of the organisms in the field is discussed.     

Protein carbonyls and antioxidant defenses in corkwing wrasse (Symphodus melops) from a heavy metal polluted and a PAH polluted site

The use of fish in environmental monitoring has become increasingly important in recent years as anthropogenic substances, many of which function as prooxidants, are accumulating in aquatic environments. We have measured a battery of antioxidant defenses as a measure of oxidative status, as well as protein carbonylation as a measure of oxidative damage, in corkwing wrasse (Symphodus melops) captured near a disused copper mine, where water and sediment are contaminated with heavy metals, and an aluminum smelter, a site contaminated with PAHs. Results were compared to two different reference sites. Fish at the heavy metal site had lower glucose-6-phosphate dehydrogenase activity and elevated protein carbonyls (1.8 times) compared to fish from the reference site. At the PAH site, EROD was increased 2-fold, while total glutathione and methemoglobin reductase concentration, were decreased. No differences were seen in protein carbonyl levels at the PAH site. Measures of both antioxidant defenses and oxidative damage should be used when assessing effects of xenobiotics on oxidative stress in fish species.     

Evaluation of toxicity in tributaries of the Mersey estuary using the isopod Asellus aquaticus (L.)

Increasing numbers of industrial, agricultural and natural chemicals are present in sewage effluent and are known to elicit toxic effects in laboratory exposures, but little is known of their combined sub-lethal effect in the field. In this study, a combination of esterase activity and ventilation rate assays was performed to determine the neurological and physiological function of the freshwater crustacean Asellus aquaticus (L.) at sites above and below a sewage treatment works (STW). Cholinesterase and carboxylesterase activities were significantly inhibited (n=8, P<0.05) and ventilation rates increased (n=8, P=0.0001) in A. aquaticus at STW sites compared to those from reference sites, indicating a decrease in neurological and physiological function. The ecological relevance of these findings for the population dynamics of the organisms in the field is discussed.     

Nrf2参与水生动物氧化应激调控的研究进展

环境变化会诱导机体活性氧(reactive oxygen species,ROS)水平升高,从而产生氧化应激.氧化应激对所有生物的生存、生长、发育和进化都具有深远的影响.核因子E2相关因子2(nuclear factor erythroid 2 related factor2,Nrf2)被公认为细胞氧化应激调控的主导者...     

Hepatic CYP1A levels and EROD activity in English sole: biomonitoring of marine contaminants in Vancouver Harbour

To assess chemical contaminant stress in the marine environment, ethoxyresorufin-O-deethylase (EROD) activity and cytochrome P450 1A (CYP1A) expression were measured in 88 English Sole (Pleuronectes vetulus) collected during May and June 1999 from four sites in Vancouver Harbour and at an expected reference site outside the harbour. Hepatic microsomes were prepared from the fish and analyzed for total CYP content, EROD activity, and CYP1A protein levels. Hepatic EROD activity and CYP1A protein levels were elevated in fish from two sites in the inner harbour. A comparison with sediment chemistry data showed that fish with increased EROD activity and CYP1A levels came from sites containing relatively high levels of polycyclic aromatic hydrocarbons and polychlorinated biphenyls. Unexpectedly high levels of EROD activity and CYP1A protein were also found in fish from a reference site near Gibsons, in Howe Sound. The elevated EROD activity and CYP1A expression in fish from this site cannot be explained by the chemical analysis data collected.     

Identification of the multidrug resistance-associated protein (mrp) related gene in red mullet (Mullus barbatus)

Multixenobiotic resistance mechanism (MXR) in aquatic organisms is mediated by the activity of the P-glycoprotein (Pgp) transporter that binds and actively effluxes different chemicals out of cell. In addition to the Pgp, several other, non-Pgp transport proteins have been recently identified in different human and animal tissues. Given their characteristics and tissue distribution we hypothesized that members of the so-called multidrug resistance-associated protein (MRP) family may be expressed in aquatic organisms. This study attempted to identify MRP related genes in different tissues of several marine and freshwater bivalves (Mytilus galloprovincialis, Dreissena polymorpha, Anodonta cygnea) and fish species (Mullus barbatus, Cyprinus carpio, Salmo trutta). Following an alignment of known MRP1 and MRP2 human sequences, as well as the GenBank available mrp2 sequences from different animals, we determined highly conserved regions and used them to design three pairs of consensus primers. Total RNA was isolated, reverse transcribed to cDNA and the obtained cDNAs were PCR amplified with the corresponding primers. The amplified PCR products were sequenced and their homology compared with Pgp and MRP protein sequences from different species. The expression of MRP related mRNA was clearly identified only in liver tissue isolated from red mullet, with homologies at the protein level ranging from 75% to 76%. Described results clearly pointed at the possibility that at least in the red mullet MXR as a general defense mechanism may be mediated by the activities of at least two different types of transport proteins.     

Impact of polychlorinated biphenyls (PCBs) on the immune function of fish: age as a variable in determining adverse outcome

Polychlorinated biphenyls (PCBs) are a major contaminant of global extent in water resources and aquatic biota. Due to its high lipid solubility, PCBs fail to be degraded and, therefore, continue to bioaccumulate throughout the environment and food chain. To determine the impact of PCBs on the immune system of aged and juvenile Japanese medaka (Oryzias latipes), fish were injected with the coplanar PCB congener 126 and examined after 3 and 14 days. PCB 126 produced oxidative stress in both age groups of fish 14 days post-injection; however, juvenile medaka appeared more susceptible than aged fish. Humoral immunity, as determined by antibody forming cell (AFC) numbers, was significantly depressed for up to 14 days post-injection in both age groups. These results demonstrate the sensitivity of the fish immune response for predicting PCB-induced immunotoxicity and identify age as a variable in determining adverse outcome.     

中国典型水域磺胺类合成药物的环境生物地球化学特征

作为广谱抗菌的人工合成药物——磺胺类(SAs)是应用最早的一类人工合成抑菌剂之一,被广泛用于人类医疗、禽畜及水产养殖等。大量磺胺类药物的应用随代谢进入水环境中,对水生生态系统和人类健康产生重要影响并构成潜在风险,截至目前,这些影响和风险并未被探明。因此,对8种典型磺胺类合成药物在我国典型水环境中的分布特征进行了阐述,评估了它们对不同水生生物的生态毒性及生态风险,并诠释了它们在生物体内的代谢及其在生态系统中的降解途径。结果表明,不同水环境中磺胺类合成药物的浓度分布差异显著,磺胺甲恶唑和磺胺嘧啶分别在水体及沉积物中的浓度和污染程度最高;水体藻类是磺胺类合成药物最敏感的水生物种,其次是甲壳类和鱼类,磺胺甲恶唑对水生生态系统构成高风险;磺胺类合成药物进入体内后被代谢成不同的产物,与母体合成药物一同进入水环境中经历降解过程;生物降解是水生生态系统中磺胺类合成药物去除的主要途径,不同种细菌、真菌及藻类均可降解磺胺类合成药物。在以后的研究中,应当进一步加强磺胺类合成药物对水生生物的慢性毒性以及合成药物混合毒性的研究,明晰水环境磺胺类合成药物的分布-代谢-传输-效应的综合过程,探析磺胺类合成药物在水生...     

Unbleached pulp mill effluents affect cytochrome P450 monooxygenase enzyme activities

The polysubstrate monooxygenase system has been shown to be highly responsive to chemical pollution. The present study summarizes the enzyme based biomonitoring of the waste waters released by a pulp mill producing unbleached pulp and paperboard. Cytochrome P4501A enzyme activities of feral and caged fish, as well as cultures of fish hepatocytes, were tested. The 7-ethoxyresorufin-O-deethylase (EROD) activity was clearly induced in fish hepatocytes exposed to biotreated unbleached pulp mill effluent fractions in vitro. The effluent increased EROD activities also in feral perch, compared with controls. Caging experiments showed similar effects to those seen in feral fish: however, the maximal induction coefficients observed were higher. Unbleached effluents contain compounds that are able to affect the P4501A activities in fish.     

Effect of seasonality on oxidative stress responses and metal accumulation in soft tissues of Aulacomya atra,a mussel from the South Atlantic Patagonian coast

This study investigated the effects of pollution and its interaction with temperature on the oxidative status of the ribbed mussel Aulacomya atra in the southern Atlantic Patagonian coast. Animals were collected from four sites with different degree and type of human activity impact, during the summer and winter of 2011. Seawater chromium, copper, manganese, nickel and zinc concentrations were measured, as well as metal accumulation, lipid peroxidation, protein oxidation, reduced glutathione levels, and enzymatic activities of superoxide dismutase and glutathione-S-transferase in gills and digestive glands.Metal bioaccumulation and oxidative stress responses in both tissues were generally higher in mussels from harbor areas. Water temperature had a remarkable effect on gill SOD activity and protein oxidation during winter in mussels from all locations.Methodologically, we conclude that measuring both metal bioaccumulation and oxidative stress responses allowed for a more accurate assessment of the biological effects of metal present in seawater.     

海洋微塑料污染现状及其对鱼类的生态毒理效应

海洋微塑料污染已成为全球性环境问题,鉴于微塑料特殊的理化性质,其对海洋生物和海洋生态系统的生态效应愈发受到关注。本文在综述海洋微塑料来源、类型和分布状况的基础上,探讨了鱼类摄入微塑料的途径及其生态毒理学效应。研究表明,全球近岸、大洋和极地海域均有微塑料分布,我国微塑料污染亦较为严重。微塑料会对包括鱼类在内的海洋生物生存造成威胁,其被鱼类摄入的主要途径是经口误食,微塑料进入鱼体后可在不同组织和器官中迁移,消化道是主要蓄积器官。微塑料对海洋鱼类的生态毒理效应主要包括:（1）影响生殖与精卵发生;（2）降低存活率;（3）影响生长发育;（4）扰乱行为;（5）导致组织病变与炎症反应;（6）导致代谢紊乱;（7）干扰神经系统;（8）导致氧化应激;（9）干扰内分泌等。未来研究应重点关注微塑料在海洋生态系统中的迁移扩散过程、不同浓度和粒径微塑料对鱼类的生态毒理效应及致毒机制研究、微塑料和其他典型海洋污染物对鱼类的联合毒性效应,以及微塑料与海洋酸化、缺氧、升温等全球环境问题的叠加效应等。     

紫外辐射对鱼类及水生无脊椎动物影响的研究进展

全球性的气候变化严重地威胁着自然生态环境间的平衡。在影响生态系统功能的诸多因素中,太阳紫外辐射的增强逐渐成为最受关注的全球性环境问题之一。太阳紫外辐射对地球生物的生命过程有着举足轻重的影响。生物体一旦吸收了高能量的紫外辐射,则可对其各种生理过程产生影响,打破内稳态,尤其是紫外辐射对DNA的损伤作用,是诱导一系列生物效应的主要原因。本文综述了近年来与鱼类及水生无脊椎动物有关的紫外辐射研究。从紫外辐射对生物不同发育时期的影响、生物对紫外线响应方式、紫外辐射与其他因素复合影响三个层面进行总结。通过总结紫外辐射对鱼类及水生无脊椎动物的影响,可为预测紫外辐射在水生生态系统中的作用提供助力,为海洋生物对环境变化的生理响应研究提供参考。     

Effects of environmental pollution in caged mussels (Mytilus galloprovincialis)

Biological effects of environmental pollution, mainly related to presence of PAHs, were assessed in mussels Mytilus galloprovincialis caged in Priolo, an anthropogenically-impacted area, and Vendicari, a reference site, both located along the eastern coastline of Sicily (Italy). PAHs concentration and histopathological changes were measured in digestive gland tissues. Expression of cytochrome P4504Y1 (CYP4Y1) and glutathione S-transferase (GST), indicative of xenobiotic detoxification, and activity of catalase (CAT) as oxidative stress index, were evaluated.The results show a direct correlation between the high concentrations of PAHs in digestive glands of mussels from Priolo and the significantly altered activity of phase I (P < 0.001) and phase II (P < 0.0001) biotransformation enzymes, along with increased levels of CAT activity (P < 0.05). These findings show the enhancement of the detoxification and antioxidant defense systems. The mussel caging approach and selected biomarkers demonstrated to be reliable for the assessment of environmental pollution effects on aquatic organisms.     

The effect of shore location on biomarker expression in wild Mytilus spp. and its comparison with long line cultivated mussels

Biomarkers are a common tool in the assessment of potential effects of contaminants in aquatic organisms. In order to identify the effects of anthropogenic pollution it is essential to identify background levels and to know the range of natural variability in the biomarker response. In this study, we examined various biomarkers of stress (glutathione S-transferase and metallothionein), damage (lipid peroxidation (LPO) and DNA damage (DNA)) and reproduction (vitellin-like proteins) in marine mussels (Mytilus spp.) from four locations along a vertical transect from high to low shore and compared them with cultivated long line mussels. High shore and cultivated mussels showed significantly higher LPO and DNA damage expression than the low shore mussels indicating a level of oxidative stress resulting from mussel location. Significant effects in physiological endpoints were also found. This study highlights the need to consider the diversity of natural environmental stress factors when using biomarkers in environmental assessment.     

Carbonyl reductase mRNA abundance and enzymatic activity as potential biomarkers of oxidative stress in marine fish

Carbonyl reductase (CBR) is an enzyme involved in protection from oxidative stress. In rainbow trout (Oncorhynchus mykiss), the hepatic mRNA abundance of the two isoforms (A and B) is increased after exposure to treated sewage effluents, as well as after exposure with β-naphthoflavone (β-NF) and the pro-oxidant paraquat. In this study, we show that the same chemicals similarly increase the single known hepatic CBR mRNA level and CBR catalytic activity in the coastal living eelpout (Zoarces viviparus). Hepatic CBR mRNA abundance and catalytic activity were also compared between eelpout collected at contaminated and reference sites on the Swedish west coast, but no differences were observed. In conclusion, CBR is a potential biomarker candidate for monitoring the exposure and effects of AhR agonists and/or pro-oxidants in the marine environment, but more research is needed to investigate temporal regulation as well as dose dependency for different chemicals. The mRNA and enzymatic assays presented in this study provide two additional tools for researchers interested in expanding their biomarker battery.     

Bioavailability of PAH in effluent water from an aluminium works evaluated by transplant caging and biliary fluorescence measurements of Atlantic cod (Gadus morhua L.)

Fixed wavelength fluorescence (FF) of bile was used as a biomarker for PAH exposure in fish caged adjacent to an aluminium works. After 30 days of caging, a 20–50 fold increase of pyrene fluorescence was found in groups caged adjacent to the works as compared to two control groups. The PAH uptake occurred mainly from suspended particles rather than from PAH contaminated sediments at the caging sites. Our results demonstrates the combined use of fish caging and bile-fluorescence measurements as a powerful field model for the monitoring of coastal waters subjected to PAH pollution.     

Neuroendocrine disruption in Mya arenaria clams during gametogenesis at sites under pollution stress

This study examined the neuroendocrine status of clams on intertidal mud flats in the St. Lawrence Estuary and Saguenay Fjord areas during late gametogenesis. The impact of pollution was determined by a test battery of early stress markers (metallothioneins, heme levels, glutathione S-transferase activity), tissue damage (lipid peroxidation and DNA damage) and morphologic characteristics (age, soft-tissue weight ratio and growth index). Neuroendocrinal status was examined by tracking serotonin and dopamine metabolism, monoamine adenylate cyclase activity in synaptosomes, monoamine oxidase and arachidonate cyclooxygenase activities in relation to gametogenetic activity: pyrimidine synthesis, (aspartate transcarbamoylase activity or ATC), vitellogenin-like proteins and gonado-somatic index. The results show that clam soft tissue weights were reduced at sites close to harbours and higher at sites near domestic wastewater outfalls. The age-to-length ratio of clams was generally higher at impacted sites, suggesting reduced growth. The biomarkers of stress or damage confirmed that oxidative stress, DNA damage, metallothioneins and glutathione S-transferase activity were significantly increased at varying degrees, at the polluted sites. Vitellogenin-like proteins and gametogenetic activity were significantly increased at sites influenced by domestic wastewaters. Furthermore, the clams were still in active gametogenesis and not ready for spawning, as indicated by the concordance of the serotonin/dopamine ratio with vitellogenin-like proteins and pyrimidine synthesis. However, gonadal cyclooxygenase activity was increased at polluted sites and significantly correlated with most of the stress biomarkers, suggesting that the clams were in a state of inflammation rather than at the spawning stage. Finally, a multivariate analysis revealed that the sites were readily discriminated with high efficiency (>71%) and that both neuroendocrine physiological markers and stress responses were identified as the major components, thus explaining the global physiological response of the clams. We conclude that the effects of pollution compromise the clams' health status and that the initiation of gametogenesis in environments contaminated by municipal wastewaters or harbours contributes to the toxic effects of pollution.     

Seasonal variation of antioxidant and biotransformation enzymes in barnacle, Balanus balanoides, and their relation with polyaromatic hydrocarbons

Seasonal variations in the antioxidant enzymes (catalase, superoxide dismutase [SOD], NADH-DT diaphorase), biotransformation enzyme, glutathione-S-transferase (GST) and microsomal lipid peroxidation in digestive tissue of barnacle, Balanus balanoides, from polluted and non-polluted populations have been evaluated. Relationships with accumulated polyaromatic hydrocarbon (PAH) concentration in barnacle tissues and environmental parameters (water temperature, salinity, dissolved oxygen concentration, water pH) were determined. As a general trend, maximum antioxidant enzyme and GST activities were detected in the pre-monsoon period or summer (March-June) followed by a gradual decrease during the monsoon (July October) with a minimum in the post-monsoon period or winter (November February). This pattern was similar to tissue concentrations of PAHs, resulting in a significant positive correlation with antioxidant enzymes, mainly catalase and SOD. Microsomal lipid peroxidation exhibited an almost reverse trend of seasonal variation to that of antioxidant enzyme activities indicating an enhanced susceptibility of barnacle tissues to oxidative stress. Among the environmental parameters, only water temperature seemed to have a significant effect on observed variations of antioxidant enzymes and GST activities. The barnacles from polluted and non-polluted populations exhibited seasonal differences in the activities of all the enzymes studied, particularly catalase, SOD and GST, suggesting the possibility of some biochemical adaptation in organisms from a chronically polluted environment. The results indicated that antioxidant defense components, catalase and SOD, are sensitive parameters that could be useful biomarkers for the evaluation of contaminated aquatic ecosystems. The results also suggested the potentiality of barnacle, B. balanoides, as a bioindicator organism against organic pollution.     

Application of the biomarker responses in scallop (Chlamys farreri) to assess metals and PAHs pollution in Jiaozhou Bay,China

Scallops (Chlamys farreri) were collected at three sites in the Jiaozhou Bay, China in April and July 2007. The responses of biomarkers were evaluated for assessment of physiological status of scallops and pollution in the areas. Compared with site S1, the activity of aryl hydrocarbon hydroxylase was induced notably (P < 0.05) and glutathione S-transferase activity was inhibited significantly (P < 0.05) in S2 and S3. The levels of DNA alkaline unwinding, DNA protein crosslinks, protein carbonyl and lipid peroxidation were tested and indicated the oxidative stress situation of scallops. There was significant difference of biomarker levels between sampling seasons (P < 0.05), and between digestive gland and gill (P < 0.05). The results provided the reference data for multiple-pollution assessment in the marine environment and indicated that tissue type and seasons affect biomarkers, therefore these factors should be taken into consideration when biomarkers are used for environmental assessment purposes.     

Unique monooxygenation pattern indicates novel flavin-containing monooxygenase in liver of rainbow trout

Vertebrate flavin-containing monooxygenases (FMOs) have only been isolated from mammalian organisms. However, many FMO substrates include pesticides which may adversely affect fish and other aquatic organisms residing in adjacent waterways to treated fields. Although FMO activities have been identified in fish, the exact isoform profile is uncertain. Utilizing prochiral methyl tolyl sulfides (MTS) and isoform-selective antibodies, an attempt was made to identify specific FMO isoforms which may be involved in sulfoxidation reactions which have been shown to bioactivate thioether pesticides, such as aldicarb. Rainbow trout hepatic microsomes treated with detergent to eliminate cytochrome P450 contributions catalyzed the formation of the sulfoxide of MTS in 75% S enantiomeric excess. These catalytic results contrast activities of the five other FMO isoforms including FMO1 (> 98% R) and FMO3 (50% R). Benzydamine N-oxidation was also observed as were methimazole, thiourea, and aldicarb sulfoxidation reactions. Antibodies to FMO1 recognized a single protein of 60 kDa in trout liver microsomes, while anti-FMO3 antibodies only slightly reacted with a 55-kDa microsomal protein. These results indicate a novel isoform profile in rainbow trout liver implicating either a mixture of competing FMO isoforms or a FMO1-like isoform displaying unique catalytic activity.