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1.
We have previously shown that largemouth bass (Micropterus salmoides) has a remarkable ability to conjugate 4-hydroxy-2-nonenal (4HNE), a mutagenic and cytotoxic alpha,beta-unsaturated aldehyde produced during the peroxidation of lipids. In addition, we have isolated a glutathione S-transferase cDNA (bass GSTA) that encodes a recombinant protein which is highly active in 4HNE conjugation and structurally similar to plaice (Pleuronectes platessa) GSTA. In the present study, HPLC-GST subunit analysis revealed the presence of at least two major GST isoforms in bass liver, with one peak constituting 80% of the total bass liver GST protein. Liquid chromatography mass spectrometry (LC-MS) and electrospray ionization analysis of the major bass GST subunit yielded a molecular weight of 26,396 kDa. Endo-proteinase Lys-C digestion and Edman degradation protein sequencing of this GST peak demonstrated that this protein was encoded by bass GSTA. Analysis of genomic DNA fragments isolated by nested PCR indicated the presence of a GST gene cluster in bass liver that contained GSTA, and was similar to a GST gene cluster characterized by Leaver et al., in plaice. Collectively, our data indicates the presence of a major GST in bass liver involved in the protection against oxidative stress. This GST is part of a gene cluster that may be conserved in certain freshwater and marine fish.  相似文献   

2.
We have previously shown that largemouth bass (Micropterus salmoides) has a remarkable ability to conjugate 4-hydroxy-2-nonenal (4HNE), a mutagenic and cytotoxic α,β-unsaturated aldehyde produced during the peroxidation of lipids. In addition, we have isolated a glutathione S-transferase cDNA (bass GSTA) that encodes a recombinant protein which is highly active in 4HNE conjugation and structurally similar to plaice (Pleuronectes platessa) GSTA. In the present study, HPLC-GST subunit analysis revealed the presence of at least two major GST isoforms in bass liver, with one peak constituting 80% of the total bass liver GST protein. Liquid chromatography mass spectrometry (LC–MS) and electrospray ionization analysis of the major bass GST subunit yielded a molecular weight of 26,396 kDa. Endo-proteinase Lys-C digestion and Edman degradation protein sequencing of this GST peak demonstrated that this protein was encoded by bass GSTA. Analysis of genomic DNA fragments isolated by nested PCR indicated the presence of a GST gene cluster in bass liver that contained GSTA, and was similar to a GST gene cluster characterized by Leaver et al., in plaice. Collectively, our data indicates the presence of a major GST in bass liver involved in the protection against oxidative stress. This GST is part of a gene cluster that may be conserved in certain freshwater and marine fish.  相似文献   

3.
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.  相似文献   

4.
5.
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 β-naphthoflavone (β-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 β-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 β-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 β-NF.  相似文献   

6.
Brown bullheads (Ameriurus nebulosus) are a demersal freshwater species that can be found in a number of polluted ecosystems. The purpose of the present study was to determine the overall capacity for in vitro glutathione S-transferase (GST) detoxification by brown bullheads, and to see if bullhead GST catalysis was altered in bullheads from a polluted site. Brown bullhead liver cytosolic GSTs catalyzed the conjugation of 1-chloro-2,4-dinitrobenzene (CDNB) over a large range of substrate concentrations, with apparent Km and Vmax for CDNB at fixed nucleophile (glutathione, GSH) concentrations of 1.8-1.9 mM and 12.1-14.6 mumol CDNB conjugated/min/mg, respectively. Bullhead GSTs were also highly active toward other substrates such as ethacrynic acid (ECA), delta 5-androstene-3,17-dione (ADI), and nitrobutyl chloride (NBC). Initial rate GST catalytic activities toward CDNB, NBC, ECA, and ADI were significantly lower in female bullheads from a contaminated lake (Lake Apopka Marsh) as compared to female bullheads inhabiting a nearby control site (Lake Woodruff). No site differences were observed with respect to male bullhead GST activities. These studies suggest that brown bullheads efficiently carry out GST conjugation of diverse electrophilic substrates. However, bullhead GST catalysis may be compromised in bullheads inhabiting polluted ecosystems.  相似文献   

7.
Hepatic microsomes and cytosols of channel catfish (Ictalurus punctatus), rainbow trout (Oncorhynchus mykiss), Atlantic salmon (Salmo salar), red tilapia (Oreochromis sp.), largemouth bass (Micropterus salmoides), striped bass (Morone saxatilis), hybrid striped bass (M. saxatilis × M. crysops), and bluegill (Lepomis macrochuris) (n = 8) were used to study the kinetics of phase I (ECOD, EROD, PROD, BROD) and phase II (UDP-glucuronosyltransferase (UDPGT)-, sulfotransferase (ST)- and glutathione-s-transferase (GST)-mediated) reactions. The best catalytic efficiency for ECOD and GST activities was performed by channel catfish, Atlantic salmon, rainbow trout and tilapia. The highest EROD catalytic efficiency was for Atlantic salmon. None of the species had either PROD or BROD activities. Rainbow trout had very similar UDPGT catalytic efficiency to tilapia, channel catfish, Atlantic salmon, largemouth bass and bluegill. Sulfotransferase conjugation had no significant differences among the species. In summary, tilapia, channel catfish, Atlantic salmon and rainbow trout had the best biotransforming capabilities; striped bass, hybrid striped bass and bluegill were low metabolizers and largemouth bass shared some capabilities with both groups.  相似文献   

8.
Baseline data for hepatic xenobiotic metabolizing biomarker enzyme activities were obtained for artificially reared tilapia Oreochromis niloticus, and were compared with those of the plaice (Pleuronectes platessa) and rainbow trout (Onchorynchus mykiss). Basal activities exhibited species variations with notably higher CYP1A and phenol UGT activities and lower GST activity in plaice than the freshwater species. Interspecies relationships between gene families determined by immunoblotting and substrate-activity profiles demonstrated the presence of homologous CYP1A and CYP3A enzymes in all three species, alpha class GSTs in plaice and trout, mu and pi class GSTs in trout and theta class GSTs in plaice and tilapia. CYP1A of tilapia was induced by 3-MC or PBO treatment, whilst CYP3A was induced by PCN treatment.  相似文献   

9.
2018年7月,浙江省某大口黑鲈(Micropterus salmoides)养殖场暴发疑似病毒引起的疾病。现场采样发现,病鱼体长约15—20cm,鱼体于水面下暗游,反应迟钝,体表有出血点或溃疡症状。本研究通过采用鲤鱼上皮瘤细胞(epithelioma papulosum cyprinid, EPC)培养、超薄切片透射电镜观察、病毒主要衣壳蛋白(majorcapsidprotein,MCP)克隆与测序分析等方法,从患病大口黑鲈中分离得到一株病毒,鉴定其属于虹彩病毒科蛙病毒属,命名为大口黑鲈虹彩病毒宁波分离株(LMBIV-NB001)。EPC经患病鱼组织匀浆液接种后出现细胞圆缩、死亡、脱落等典型的细胞病变症状。将感染后的EPC细胞制作超薄切片,通过电镜观察发现,EPC细胞质中存在大量直径约120nm具囊膜的正六边形成熟病毒粒子,形态与虹彩病毒相似。根据虹彩病毒MCP基因保守区域序列设计特异性引物对病鱼组织样本进行PCR扩增,获得了1029bp的目的基因片段。将该扩增片段连入pMD19-T simple质粒后测序,经BLAST比对分析显示,其与GenBank中已报道的鳜鱼蛙病毒NH-1609、大口黑鲈溃疡综合征病毒BG/TH/CU3、EPC060608-08的MCP基因同源性最高,相似度均达到99.13%。构建系统进化树分析表明,本研究分离的LMBIV-NB001株与NC_038508、GU256635、MG941005等虹彩病毒科蛙病毒属毒株聚成一簇。本论文研究结果为不同地区蛙病毒属成员的起源和分化等相关研究等提供了基础材料。  相似文献   

10.
The major glutathione S-transferase isoform of flounder liver, an antigenically related structural homologue of plaice GST-A, also displays mRNA homology. A 901bp cRNA probe for plaice GST-A cross-hybridised to a 1100bp flounder mRNA on northern blot analysis. The plaice antibody and cRNA probes were used to study effects of inducer treatment on GST-A expression in flounder liver. Six days after PAH treatment (3-methylcholanthrene) total hepatic GST activity was halved, levels of GST-A were 80% and GST-A mRNA levels were 25% of controls. A commercial PCB mixture (Aroclor 1254TM) had little effect on total GST or GST-A levels despite halving GST-A mRNA levels. An epoxide, trans-stilbene oxide induced total GST activity 1·4 fold and GST-A protein levels 1·8-fold and its mRNA levels 3-fold. This reduced expression of the major flounder hepatic GST by agents which induce cytochrome P4501A1 may modulate cytoxicity of environmental pollutants in this species.  相似文献   

11.
采用RT-PCR技术和RACE技术成功克隆淡水鱼类斑鳢sGST基因cDNA全序列,推测得到氨基酸序列,初步分析其结构功能域及系统进化关系。结果表明,斑鳢sGST基因cDNA序列全长为898bp,编码225个氨基酸。斑鳢sGST与真鲷、金头鲷、鲽、黑头鲦、川鲽、大口黑鲈等最新定名为ρ型的sGST氨基酸同源性较高,ρ型sGST为水生生物所特有并共同占据进化树上独立的分枝;与大鼠、小鼠、人等哺乳动物sGST现有所有类型同源性均很低,并且在进化树上距离也较远,表明本研究成功克隆的sGST基因应属于ρ型,可能在鱼类等水生生物对水栖环境的适应上有重要作用。  相似文献   

12.
Known characteristics of the largemouth black bass, Micropterus salmoides (Lacépède), in its natural habitats in North America and as an introduction in other areas are discussed in relation to the suggestion that the fish should be introduced into New Zealand. It is concluded that much more research on the New Zealand ecosystems is necessary before a realistic assessment can be made of the likely effects of the predatory bass on indigenous fish and on trout fisheries.  相似文献   

13.
Previous studies suggested that dietary composition affected glutathione S-transferase (GST) activity in catfish intestine, and this activity varied along the intestine. In this study, catfish were fed a semi-purified diet or a commercial chow for at least 2 weeks. GST activity, percent protein cross-reacting with anti-catfish GST pi antibody, and immuno-cross-reactivity with antibodies specific for human alpha, mu, pi and theta class GSTs were determined in cytosol prepared from sections of proximal, medial, and distal intestine. The bulk of GST activity with 1-chloro-2,4-dinitrobenzene (CDNB) and ethacrynic acid, and the percent protein cross-reacting with anti-catfish GST pi were in the more proximal segments and dropped off distally in the two diet groups. The percent of cross-reacting GST protein in the proximal section of fish fed on commercial chow was significantly higher (4.3 +/- 1.7%) than in fish fed purified diet (2.3 +/- 0.2%). Further Western blot analysis revealed a differential expression of GST isoforms only in the distal segment of fish fed commercial chow that recognized human anti-alpha GST antibody. Distal intestinal segments of catfish exposed to 3,3',4,4'-tetrachlorobiphenyl (TCB) and beta-naphthoflavone (BNF) also revealed expression of distinct alpha-like GST isoforms. Results strongly suggest the distal segment as a site for potential biomarkers for polycyclic aromatic hydrocarbon (PAH)- and co-planar polychlorinated biphenyl (PCB)-type contaminants.  相似文献   

14.
Common dab were fed a casein based diet containing copper at a concentration of 1·4 mg copper kg−1 (dry weight) or a similar diet supplemented with 200 mg copper kg−1. Fish were sampled after 10 weeks and 20 weeks and hepatic and renal copper, zinc and metallothionein concentrations were measured. All hepatic cytosolic copper in test and control fish co-eluted from Sephadex G-75 with metallothionein, as did some of the cytosolic zinc. After 20 weeks there was three times as much of this metallothionein-bound copper in the livers of the test fish compared to the control fish, although metallothionein concentration was little elevated. On the basis of these results it is proposed that cytosolic liver copper concentration or heat stable liver copper concentration can be used as an indication of excess dietary copper in the dab Limanda limanda.  相似文献   

15.
Hepatic levels of Cu, Zn and metallothionein (MT) in perch, caught in a Cu/Zn gradient from a brassworks, reflected the water concentration of Cu (1·0–9·4 ppb) and Zn (0·56–59 ppb). Significant correlations were found between hepatic Cu and MT levels (r = 0·72), and between Zn and MT levels (r = 0·69). There was an increase of the amount of Cu and Zn in the cytosolic fraction of the liver with increased hepatic levels of the metals. When liver samples. from perch caught at the most contaminated location, were run on a gel filtration column (Sephadex G-75) 78% of the cytosolic Cu and 24% of the Zn in the cytosol eluted together with MT.  相似文献   

16.
A cDNA clone for glutathione S-transferaseA (GSTA) from plaice (Pleuronectes platessa) was expressed in Eschericia coli (E. coli) and purified to homogeneity by S-hexylglutathione affinity chromatography. When compared to literature values for a variety of purified mammalian GSTs, the heterologously expressed purified plaice enzyme had moderate activity towards the model substrate 1,2-chloro-2,4-dinitrobenzene (CDNB) and exhibited a Km of 2.5 ± 2 mM and Vmax of 30.9 ± 2.3 μmol min−1 mg−1. It had little or no activity towards several other model GST substrates including 1,2-dinitrochloro-4-benzene (DCNB), ethacrynic acid (EA), and p-nitrobenzylchloride (NBC). However plaice GSTA was a relatively efficient catalyst for the conjugation of a series of alk-2-enals and alk-2,4-dienals and also 4-hydroxynonenal. The highest activity observed with this series of substrates was with trans-non-2-enal with a Km of 17.9 ± 2.2 μM and a Vmax of 3.01 ± 0.57 μmol min−1 mg−1. These unsaturated alkenals have been identified in cells and cell extracts as highly toxic products arising from peroxidation of unsaturated fatty acids particularly during periods of oxidative stress. Fish are relatively rich in polyunsaturated fatty acids and thus GSTA mediated conjugation may be an important mechanism for detoxifying peroxidised lipid breakdown products.  相似文献   

17.
In order to evaluate the gill glutathione S-transferase (GST) activity as a biomarker of effect of fungicide exposure in juvenile brown trout (Salmo trutta), the fungicides propiconazole [(R,S)-1-[2-(2,4-diclophenyl)-4-propyl-1,3-dioolan-2-ylmetyl]-1H-1,2,4-triazole] and fenpropimorph [(+/-)-cis-4-[3-(4-tert-butylphenyl)-2-metyl propyl]-2,6 dimetylmorfolinc] were administrated in the water separately and together in a static system (80 microg/l for each pesticide) for 5 days. The combined fungicides gave a significant decrease in gill GST activity towards 1-chloro-2,4-dinitrobenzene (CDNB), whilst hepatic GST-activity was not significantly changed. Furthermore, continuous exposure to 540 ug/l thiabendazole[2-(thiazol-4'-yl)benzimidazole] in a flow-through system for 4 days significantly increased the gill glutathione S-transferase (GST) activity towards CDNB, whilst hepatic GST and cytochrome P450 (CYP 1A) activities were not increased by the treatment.  相似文献   

18.
为研究重金属铅离子对大口黑鲈(Micropterus salmoides)幼鱼Hippo信号通路中主要基因表达的影响,本实验采用qPCR技术研究了96 h急性不同浓度铅胁迫(0、10、17.8、31.6、56.2和100 mg/L)下Hippo信号通路中的部分基因在肝脏、肌肉、鳃和小肠组织中的mRNA表达量变化。结果显示:与对照组(0 mg/L)相比,七个基因在肝脏组织中表达量变化总体上呈上升趋势,除Lats1/2外,其他基因在铅胁迫浓度(17.8 mg/L)时都显著上调(P<0.05);在肌肉组织中,MOB1表达量在不同浓度铅胁迫下上升显著(P<0.05);在腮组织中,YAP/TAZ、TEAD、PP2A、MOB1、KIBRA和FRMD表达量在铅胁迫浓度(10 mg/L)时显著上调(P<0.05);在小肠组织中,PP2A、KIBRA和14-3-3表达量显著下降(P<0.05)。结果提示大口黑鲈可能通过调节Hippo信号通路中相关基因的表达响应铅胁迫。  相似文献   

19.
In this study male largemouth bass (LMB) were exposed to the naturally occurring androgens, dihydrotestosterone (DHT) or 11-ketotestosterone (11-KT) in order to identify genes that are differentially regulated by these steroid hormones. Using subtractive hybridization on livers of fish treated with DHT against vehicle control, many novel LMB genes were cloned. These genes were added to our gene library and arrayed. Six genes were up-regulated and five were down-regulated by both androgens. But, each androgen also regulated specific genes. One gene that was identified as a potential androgen marker was spermidine-spermine-N(1)-acetyltransferase that was up-regulated by both androgens. Determining which genes are responsive to natural androgens will help to identify biochemical pathways that are impacted.  相似文献   

20.
The initial sampling in the Marine Monitoring Program (MOMAM), coordinated by the Ministry of Marine Affairs (IEAPM), was performed along the southeast coast of Brazil. Orthopristis ruber samples were collected at Guanabara, Sepetiba and Ilha Grande Bays. Microsomal CYP1A levels and cytosolic cholinesterase (ChE), catalase (CAT) and glutathione S-transferase (GST) activities were measured in the liver of these fish according to established procedures. CAT activity and CYP1A content were significantly higher (P < or = 0.05) in fish caught at Guanabara Bay, which might be due to higher levels of peroxisome proliferators and Ah receptor agonists, respectively, at this site compared to the other sites. Also, lower GST activity was observed in fish from this site, which may possibly be related to the presence of oxidative-stress inducing compounds.  相似文献   

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