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1.
In order to assess its potential as a biomarker of aquatic pollution, an alpha class glutathione S-transferase gene (GSTalpha gene) was cloned from the small hermaphroditic fish Rivulus marmoratus. The R. marmoratus GSTalpha gene spanned 1.3 kb, consisting of 6 exons encoding 221 amino acid residues. It showed high similarity to zebrafish GST. We named this R. marmoratus GSTalpha gene as rm-GSTalpha. The cDNA of the rm-GSTalpha gene was also investigated for its phylogeny, tissue-specific and chemical-induced expression. Rm-GSTalpha was subcloned into a 6 x His-tagged pCRT7 TOPO TA expression vector to produce the recombinant 6 x His-tagged rm-GST protein. This will be used in future to raise an rm-GSTalpha antibody for use in the study of phase II metabolism involved in detoxification. We also exposed R. marmoratus to 300 microg/l of 4-nonylphenol in water, and found approximately 4-fold induction of R. marmoratus GSTalpha mRNA in the treated animals. In this paper, we discuss the characteristics of the R. marmoratus GSTalpha gene as well as its potential use in relation to environmental pollution.  相似文献   

2.
In recent years, there has been a decline in the wild populations of river pufferfish, Takifugu obscurus. Besides overexploitation for commercial purposes, environmental pollution is believed to have contributed to its decline. However, almost no information exists about genes involved in metabolism of xenobiotics by this species. Nevertheless, there is interest in fugu fishes, since they possess the smallest genome among vertebrates. We cloned and characterized the full-length cDNA sequence of a cytochrome P450 1A (CYP1A) gene from T. obscurus. Phylogenic relationship of T. obscurus CYP1A was also compared to other fish species. The tissue distribution and time-dependant induction of CYP1A mRNA were studied by real-time PCR in T. obscurus exposed to an aryl hydrocarbon receptor (Ahr) agonist, beta-naphthoflavone (BNF). The greatest basal expression in livers of control as well as BNF-treated individuals. However, brain, gill, gonad, intestine, and kidney also expressed CYP1A. Muscles expressed the least CYP1A. The results of the time-course study revealed induction in brain and gills after 6h and at 12h in most tissues. Except for gills, all other organs retained induced expression of CYP1A mRNA up to 96h.  相似文献   

3.
A variety of sources of organic contaminants to the Great Barrier Reef lagoon and near-shore environment exist including boating activity, agriculture and urban run-off. Cytochrome P-450 1A activity as measured by ethoxy-resorufin O-deethylase (EROD) activity has been widely used as an indicator of the exposure of fish to organic contaminants such as polychlorinated biphenyls (PCB), polycyclic aromatic hydrocarbons (PAH) and some organochlorine pesticides. This study demonstrates the successful application of EROD measurements in a common Australian tropical estuarine fish species, Acanthopagrus berda (Pikey Bream), to identify areas under potential stress from organic contaminants. Fish were captured from four creeks draining agricultural land, a creek draining urban land and two creeks with less disturbed catchments. Significant induction of cytochrome P450-1A was observed in fish captured from Ross Creek (urban catchment, 7.4-fold) and Cromarty Creek (agricultural catchment, 6.4-fold). Increased activity was also observed in fish captured from other creeks draining agricultural land (Plantation Creek, Victoria Creek, Seymour River, 1.9–2.6-fold) as compared to those captured from creeks in undisturbed catchments (Baldy Creek, Fisher Creek, 67–114 pmol/min/mg protein).  相似文献   

4.
The relationships among cytochrome P450 induction in marine wildlife species, levels of fluorescent aromatic compounds (FAC) in their bile, the chemical composition of the inducing compounds, the significance of the exposure pathway, and any resulting injury, as a consequence of exposure to crude oil following a spill, are reviewed. Fish collected after oil spills often show increases in cytochrome P450 system activity, cytochrome P4501A (CYP1A) and bile fluorescent aromatic compounds (FAC), that are correlated with exposure to polycyclic aromatic hydrocarbons (PAH) in the oil. There is also some evidence for increases in bile FAC and induction of cytochrome P450 in marine birds and mammals after oil spills. However, when observed, increases in these exposure indicators are transitory and generally decrease to background levels within one year after the exposure. Laboratory studies have shown induction of cytochrome P450 systems occurs after exposure of fish to crude oil in water, sediment or food. Most of the PAH found in crude oil (dominantly 2- and 3-ring PAH) are not strong inducers of cytochrome P450. Exposure to the 4-ring chrysenes or the photooxidized products of the PAH may account for the cytochrome P450 responses in fish collected from oil-spill sites. The contribution of non-spill background PAH, particularly combustion-derived (pyrogenic) PAH, to bile FAC and cytochrome P450 system responses can be confounding and needs to be considered when evaluating oil spill effects. The ubiquity of pyrogenic PAH makes it important to fully characterize all sources of PAH, including PAH from natural resources, e.g. retene, in oil spill studies. In addition, such parameters as species, sex, age, ambient temperature and season need to be taken into account. While increases in fish bile FAC and cytochrome P450 system responses, can together, be sensitive general indicators of PAH exposure after an oil spill, there is little unequivocal evidence to suggest a linkage to higher order biological effects, e.g. toxicity, lesions, reproductive failure.  相似文献   

5.
In recent years, there has been a decline in the wild populations of river pufferfish, Takifugu obscurus. Besides overexploitation for commercial purposes, environmental pollution is believed to have contributed to its decline. However, almost no information exists about genes involved in metabolism of xenobiotics by this species. Nevertheless, there is interest in fugu fishes, since they possess the smallest genome among vertebrates. We cloned and characterized the full-length cDNA sequence of a cytochrome P450 1A (CYP1A) gene from T. obscurus. Phylogenic relationship of T. obscurus CYP1A was also compared to other fish species. The tissue distribution and time-dependant induction of CYP1A mRNA were studied by real-time PCR in T. obscurus exposed to an aryl hydrocarbon receptor (Ahr) agonist, β-naphthoflavone (BNF). The greatest basal expression in livers of control as well as BNF-treated individuals. However, brain, gill, gonad, intestine, and kidney also expressed CYP1A. Muscles expressed the least CYP1A. The results of the time-course study revealed induction in brain and gills after 6 h and at 12 h in most tissues. Except for gills, all other organs retained induced expression of CYP1A mRNA up to 96 h.  相似文献   

6.
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7.
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8.
Roach, goby and sturgeon were examined for cytochrome P4501A (CYP1A) expression and histopathology, in relation to contaminant burdens in fish and sediment. Gradients of induction of CYP1A were observed. Roach from the Ural and Ily River Deltas and roach and goby from the two stations nearest the Caspian Sea oil fields displayed higher levels of CYP1A expression in several organs than was observed in fish from further offshore. Great sturgeon and Russian sturgeon showed higher levels of CYP1A expression than was seen in starred sturgeon and gobies in the Ural delta. No fish showed evidence of contaminant-related histopathologies in the organs examined, despite the elevated CYP1A levels. Low levels of polychlorinated biphenyls and elevated levels of inshore and riverine petroleum hydrocarbons from these habitats suggest that this ongoing hydrocarbon exposure, and that from natural sources and long-term oil exploration on the Northeastern Caspian shore, contributed to the CYP1A induction observed.  相似文献   

9.
Large mysticete whales represent a unique challenge for chemical risk assessment. Few epidemiological investigations are possible due to the low incidence of adult stranding events. Similarly their often extreme life-history adaptations of prolonged migration and fasting challenge exposure assumptions. Molecular biomarkers offer the potential to complement information yielded through tissue chemical analysis, as well as providing evidence of a molecular response to chemical exposure. In this study we confirm the presence of cytochrome P450 reductase (CPR) and cytochrome P450 isoenzyme 1A1 (CYP1A1) in epidermal tissue of southern hemisphere humpback whales (Megaptera novaeangliae). The detection of CYP1A1 in the integument of the humpback whale affords the opportunity for further quantitative non-destructive investigations of enzyme activity as a function of chemical stress.  相似文献   

10.
The elastic moduli of ScAlO3 perovskite, a very close structural analogue for MgSiO3 perovskite, have been measured between 300 and 600 K using high precision ultrasonic interferometry in an internally heated gas-charged pressure vessel. This new capability for high temperature measurement of elastic wave speeds has been demonstrated on polycrystalline alumina. The temperature derivatives of elastic moduli of Al2O3 measured in this study agree within 15% with expectations based on published single-crystal data. For ScAlO3 perovskite, the value of (∂KS/∂T)P is −0.033 GPa K−1 and (∂G/∂T)P is −0.015 GPa K−1. The relative magnitudes of these derivatives agree with the observation in Duffy and Anderson [Duffy, T.S., Anderson, D.L., 1989. Seismic velocities in mantle minerals and the mineralogy of the upper mantle. J. Geophys. Res. 94, 1895–1912.] that |(∂KS/∂T)P| is typically about twice |(∂G/∂T)P|. The value of (∂KS/∂T)P for ScAlO3 is intermediate between those inferred less directly from V(P,T) studies of Fe-free and Fe- and Al-bearing MgSiO3 perovskites [Wang, Y., Weidner, D.J., Liebermann, R.C., Zhao, Y., 1994. P–V–T equation of state of (Mg,Fe)SiO3 perovskite: constraints on composition of the lower mantle. Phys. Earth Planet. Inter. 83, 13–40; Mao, H.K., Hemley, R.J., Shu, J., Chen, L., Jephcoat, A.P., Wu, Y., Bassett, W.A., 1991. Effect of pressure, temperature and composition on the lattice parameters and density of (Mg,Fe) SiO3 perovskite to 30 GPa. J. Geophys. Res. 91, 8069–8079; Zhang, Weidner, D., 1999. Thermal equation of state of aluminum-enriched silicate perovskite. Science 284, 782–784]. The value of |(∂G/∂T)|P for ScAlO3 is similar to those of most other mantle silicate phases but lower than the recent determination for MgSiO3 perovskite [Sinelnikov, Y., Chen, G., Neuville, D.R., Vaughan, M.T., Liebermann, R.C., 1998. Ultrasonic shear wave velocities of MgSiO3 perovskite at 8 GPa and 800K and lower mantle composition. Science 281, 677–679].

Combining the results from the previous studies and current measurements on ScAlO3 perovskite, we extracted the parameters (q and γ0) needed to fully specify its Mie–Grüneisen–Debye equation-of-state. In this study, we have demonstrated that acoustic measurements of KS(T), unlike V(P,T) data, tightly constrain the value of q. It is concluded that ScAlO3 has ‘normal’ γ0 (1.3) and high q (3.6). The high value of q indicates that ScAlO3 has very strong intrinsic temperature dependence of the bulk modulus; similar behaviour has been observed in measurements on Fe- and Al-bearing silicate perovskites (Mao et al., 1991; Zhang and Weidner, 1999).  相似文献   


11.
The dytiscid beetle Rhantus sikkimensis, Regimbart, 1899 (Coleoptera: Dytiscidae), a member of the freshwater insect communities of the Darjeeling Himalayas, were noted to predate on the coexisting larvae of Chironomus sp. Meigen. Evaluation of predation by R. sikkimensis on Chironomus sp. larvae, in the laboratory, revealed that a single adult morph of R. sikkimensis could kill and consume on an average 10–90 and 10–78 numbers of small and large Chironomus sp. larvae, respectively, per day, depending on the prey density. The attack rate ranged between 520 and 537, and the handling time ranged between 4.3 and 8.6 depending on the size of the preys. The predation varied with respect to predator density also, with a maximum of 151 larvae killed by three predators per day. Two indices of predation, ingestion rate (IR) ranging between 13.33 and 74.15 larvae/day/predator and clearance rate (CR) ranging between 19.67 and 39.99 L prey/day/predator, varied with the prey size and predator density, significantly, when the predation was observed for 9 consecutive days, at two predator densities. It was also noted that R. sikkimensis predated on an average 9.8 larvae of Chironomus sp. and 1 larva of Culex sp., when the larvae of both the species are present together as preys, showing a preference for the Chironomus sp. larvae.  相似文献   

12.
Abstract

Techniques are proposed for developing a monthly and weekly drought outlook and the drought outlook components are evaluated. A drought index, the surface water supply index (SWSI) was modified and used for the drought outlook. A water balance model (abcd) was successfully calibrated using a regional regression, including monthly and weekly factors, and was used to convert meteorology to hydrology. For the monthly drought outlook, an ensemble technique was applied, both with and without monthly industrial meteorology information (MIMI). For the weekly drought outlook, a deterministic forecasting technique was applied employing the Global Data Assimilation and Prediction System (GDAPS). The methodologies were applied to the Geum River basin in Korea. While only the weekly outlook using the GDAPS has sufficient forecasting capability to suggest it might be useful, the accuracy of the monthly drought outlook is expected to improve as the climate forecast accuracy increases.

Editor Z.W. Kundzewicz; Associate editor D. Hughes

Citation Kim, Y.-O., Lee, J.-K., and Palmer, R.N., 2012. A drought outlook study in Korea. Hydrological Sciences Journal, 57 (6), 1141–1153.  相似文献   

13.
This study presents full-length cDNA sequences of CYP1A1 and 1A2, in common minke whale (Balaenoptera acutorostrata) from the North Pacific. Both CYP1A1 and CYP1A2 cDNAs had an open reading frame of 516 amino acid residues, and predicted molecular masses were 58.3 kDa and 58.1 kDa, respectively. The deduced full-length amino acid sequence of CYP1A1 revealed higher identities with those of sheep (86%) and pig (87%), and that of CYP1A2 was most closely related to human (82%) and monkey CYP1A2 (82%) among species from which CYP1A2 has been isolated so far. Differences in certain conserved and functional amino acid residues of CYP1A1 and 1A2 between common minke whale and other mammalian species indicate the possibility of their specific metabolic function. Concentrations of organochlorine compounds (OCs) including PCBs and DDTs analyzed in common minke whale liver showed no significant correlation with hepatic mRNA expression levels of CYP1A1 and CYP1A2, indicating no induction of these enzymes by such OCs.  相似文献   

14.
A redetermination of the isotopic composition of atmospheric argon by Lee, J.-Y., Marti, K., Severinghaus, J.P., Kawamura, K., Yoo, H.-S., Lee, J.B., Kim, J.S. [2006. A redetermination of the isotopic abundances of atmospheric Ar. Geochimica et Cosmochimica Acta 70, 4507–4512] represents the first refinement since the work of Nier [1950. A redetermination of the relative abundances of the isotopes of carbon, nitrogen, oxygen, argon, and potassium. Physical Reviews 77, 789–793]. The new 40Ar:38Ar:36Ar proportions imply <1% adjustments to 40Ar/39Ar ages in all but exceptional cases of very young and/or K-poor and/or Ca-rich samples, or cases in which samples are grossly under- or over-irradiated. Analytical protocols employing atmospheric argon to determine mass discrimination corrections are insensitive to the effects of revision on the air correction, but are subject to non-negligible adjustments arising from expanded heavy to light isotope ratios attending the increased mass discrimination correction. The competing effects of increased 40Ar/39Ar and 40Ar/37Ar ratios render the adjustments a function of sample chemistry and neutron irradiation parameters. The improved precision of atmospheric 40Ar/36Ar and 38Ar/36Ar permits increasingly sensitive detection of departures from atmospheric values. Non-atmospheric initial 40Ar/36Ar values are increasingly well-documented in volcanic materials, including subatmospheric values correlated with 38Ar/36Ar in a trend consistent with kinetic mass fractionation whereby incomplete equilibration between magma and atmosphere favors light isotope enrichment in the magma. The detailed mechanism(s) of such fractionation are unclear and must be clarified by further study. A detectable increase in atmospheric 40Ar/36Ar in the past 800 ka [Bender, M.L., Barnett, B., Dreyfus, G., Jouzel, J., Porcelli, D., 2008. The contemporary degassing rate of 40Ar from the Earth. Proceedings of the National Academy of Sciences 105, 8232–8237] suggests that ages of late Quaternary (e.g., <100 ka) materials incorporating large amounts of atmospheric argon such as biotite may be underestimated by as much as 100% if a modern atmospheric 40Ar/36Ar value is erroneously assumed, unless air argon is used to determine mass discrimination. Further evaluation of the evolution of paleoatmospheric 40Ar/36Ar, and the fidelity with which argon trapped in igneous materials reflects this, would be very productive. The use of isochrons rather than model (e.g., plateau) ages mitigates the vagaries associated with uncertain trapped argon isotope ratios, and the importance of strategies to derive statistically valid isochrons is underscored.  相似文献   

15.
《Marine pollution bulletin》2012,64(5-12):166-171
Fish consumption is known to be beneficial to human health. However since the age of industrialization, the released/disposed chemical pollutants into water systems make fish a source of various environmental toxicants to humans. In oceanic cities with heavy industrial activities, fish products contribute the greatest proportion of exposure to pollutants. In this study, risks and potential effects of dioxins to health of coastal populations in the Pearl River Delta were assessed. Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) were measured in common fish species purchased at local markets. Concentrations of total dioxins in fish ranged from 0.481 to 9.05 pg TEQ/g wet weight were similar to the lesser concentrations reported for fish from other countries. The greatest concentrations of dioxins were measured in mandarin fish, a carnivorous freshwater fish. Exposure of murine primary leydig and ovarian cells to 2,3,7,8-tetrachlorinated dibenzo-p-dioxins (2,3,7,8-TCDD) reduced the synthesis of progesterone, testosterone and/or estrogen. The reductions were probably via inhibitory effects on the expression of the steroidogenic enzymes, steroidogenic acute regulatory protein (StAR) and cytochrome P450 side-chain cleavage enzyme (P450scc). Based on these reproductive parameters, the concentrations of dioxins and dioxin-like residues represent a moderate health risk due to consumption of fish.  相似文献   

16.
Ras is regarded as one of the most important genes involved in carcinogenesis. Such genes have been characterised in several fish species and the presence of ras mutations have already been described in fish populations from hydrocarbon contaminated areas and following experimental exposure to specific contaminants. The aims of this study were to evaluate the DNA integrity by comet assay, to isolate the normal ras gene of Anguilla anguilla and analyse for the presence of ras gene mutations or changes in gene expression levels induced after one month of benzo[a]pyrene (BaP) experimental exposure. The A. anguilla ras cDNA isolated revealed a 189 amino acid protein and alignment with other vertebrate ras proteins revealed conservation of functionally important regions. Following experimental exposure to BaP, an increase in DNA damage was found by comet assay. However, no point mutations or changes in ras gene expression levels were detected when compared to control samples. In contrast to the majority of fish ras gene sequences, a high degree of polymorphic variation was detected in the A. anguilla ras gene.  相似文献   

17.
基于第二代Curvelet变换的面波压制(英文)   总被引：3，自引：2，他引：1  
针对面波能量强、频率低、视速度低等特点,本文提出了基于第二代Curvelet变换的多尺度、多方向分解的面波压制方法,充分利用Curvelet变换的多尺度、多方向功能,分离出含有面波的尺度和方向然后利用面波与有效波在Curvelet域基本不重叠的特性,进行信噪分离处理。这种方法在实际叠前地震数据的处理中,能够有效压制面波,同时较好地保护有效反射波,特别是反射波的低频分量。文中提出的基于第二代Curvelet变换的去面波方法是一种较好的保幅去噪方法。  相似文献   

18.
Hepatic microsomal 7-ethoxyresorufin O-deethylase (EROD) activities (indicative of exposure to polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs)) were measured in eel Anguilla anguilla from the Thames Estuary. Fish were collected from up to 13 sites during November 1997, May and August 1998 and October 1999. Throughout this period no clear seasonal variation could be identified at every site along the Thames. However, during the summer months, fish sampled from sites in the middle to the upper estuary (Woolwich, Greenhithe and West Thurrock) reported up to 3-fold higher EROD activities compared to sites either at the upper reaches (Richmond and Brentford) at the same time of the year, or fish sampled in winter, along the entire length of the estuary. A laboratory exposure experiment demonstrated a 3-fold elevation of EROD activity 2 days after injection with β-naphthoflavone (β-NF). However, higher levels of activity could be determined in fish sampled from the Weston canal near the Merseyside. The lowest levels of A. anguilla EROD activity were observed in fish sampled from the upper reaches of the River Tamar, Devon, and were comparable to activities determined in fish from the Wear and Humber estuaries. A. anguilla sampled along the Thames, Tyne and Tees estuaries reported between 2.5- and 7-fold higher EROD activities compared to fish collected from the Tamar. These results indicate that a low to moderate induction of A. anguilla CYP1A had occurred (indicative of low to moderate exposure to PAHs and planar PCBs) in fish collected from the Thames, Tyne, Wear, Tees, Humber and Tamar estuaries. However, the highest level of EROD activity was observed in fish from the Weston Canal (Merseyside).  相似文献   

19.
The aim of the present study was to evaluate the mixed function oxidase (MFO) system and the forms of supposed cytochrome P-450 in the liver of black-headed gulls (Larus ridibundus) feeding in a lagoon and on a garbage dump. Tissue levels of polychlorinated biphenyls (PCBs) were also determined. Ethoxyresorufin 10-deethylase (EROD) and aldrin epoxidase activities were higher in the dump gulls than in the lagoon gulls. A marked thickening of the proteins in the cytochrome P-450 area, particularly of P-450c and P-450d, was also found in the dump gulls. No relationship was found between MFO activity and tissue chlorinated hydrocarbon levels.  相似文献   

20.
The study describes cytochrome P450 1A1 (CYPA1) expression in the skin of different cetacean species (Megaptera novaeangliae, n = 15; Stenella attenuata, n = 7 and Stenella longirostris, n = 24) from the Mozambique Channel island of Mayotte. Immunohistochemical examination was performed with a monoclonal antibody against scup cytochrome CYPA1. The sex was determined using a molecular approach consisting in the genotyping sex-specific genes. CYPA1 was detected at the junction between epidermis and blubber on dolphins only, mostly in the endothelial cells. Similar observation was obtained in the dermis of one M. novaeangliae. Immunohistochemical slides were scored to evaluate the expression of the CYPA1 and a higher expression was observed in S. longirostris, suggesting a higher exposure to pollutants for this species. The difference of expression between sexes was not significant.  相似文献   

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