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1.
In several species of Acaridae (Astigmata), heteromorphic males, possessing a sharply terminated third pair of legs which they use to mortally stab other males, coexist with scrambler males with unmodified legs. Previous research showed that in the bulb mite, Rhizoglyphus robini (Claparède), the male morph is heritable. In this study I used a different population and carried out selection in both downward and upward direction in order to change the proportion of morphs. Starting from the proportion of about 0.2 homeomorphs in the population, I obtained a significant response to 8–10 generations of selection in two repetitions. The response was asymmetrical (stronger in upward direction). Realised heritabilities were in the range of 0.3 (downward) and 0.8 (upward).  相似文献   

2.
汤方  李丽  高希武 《昆虫知识》2012,49(6):1513-1518
本论文采用分光光度计法研究了植物次生物质和杀虫剂对分月扇舟蛾Closteraanastomosis(L.)谷胱甘肽S-转移酶(GSTs)的体外抑制作用。结果表明各植物次生物质和杀虫剂对分月扇舟蛾GSTs活性的体外抑制作用存在差异。当植物次生物质和杀虫剂终浓度为8.34×10-5mol/L时,槲皮素和单宁酸对分月扇舟蛾GSTs活性抑制作用最强,分别为64.41%和58.61%;三唑磷、毒死蜱、辛硫磷、氟铃脲、氟虫腈和哒螨灵都有较强的抑制作用,对GSTs活性抑制率超过20%;氧化乐果、水胺硫磷、丙溴磷、马拉硫磷、灭多威、联苯菊酯、高效氯氰菊酯、甲氰菊酯、高效氯氟氰菊酯、吡虫啉和啶虫脒对分月扇舟蛾GSTs有中等抑制作用;其他杀虫剂对分月扇舟蛾GSTs有较弱(或没有)抑制作用。此外,在一定的浓度范围内,槲皮素、单宁酸和辛硫磷对分月扇舟蛾GSTs活性的抑制作用存在明显的剂量效应关系。槲皮素、单宁酸和辛硫磷对分月扇舟蛾GSTs的抑制中浓度分别为2.19×10-5,2.62×10-5,1.49×10-4mol/L。因此,此研究明确了槲皮素和单宁酸作为防治分月扇舟蛾的新型防治剂或增效剂具有很好的潜力。  相似文献   

3.
Summary Arsenic-resistant Chinese hamster ovary (CHO) cells were established by progressively increasing the concentration of sodium arsenite in culture medium. One of the resistant clones, SA7, was also cross-resistant to As(V), Zn, Fe(II), Co, and Hg. The susceptibilities to sodium arsenite in parental CHO cells, revertant SA7N cells, and resistant SA7 cells were correlated with their intracellular glutathione (GSH) levels and glutathione S-transferase (GST) activity. The resistance in SA7 cells was diminished by depletion of GSH in cells after treatment with buthionine sulfoximine. Furthermore, after reexposure of revertant SA7N cells to sodium arsenite, the intracellular GSH levels, GST activity, and resistance to sodium arsenite were raised to the same levels as SA7 cells. These data indicate that the elevation of intracellular GSH levels and GST activity in SA7 cells may be responsible for the resistance to arsenite. A p25 protein, which could be a monomer subunit of GST, accumulated in SA7 cells. In addition, an outward transport inhibitor, verapamil, indiscriminately increased the arsenite toxicity in resistant and parental cells. This work was supported in part by grant NSC77-0201-B001-31 from the National Science Council, Republic of China.  相似文献   

4.
Glutathione S-transferase (28GST) with molecular mass of 28 kDa is an antioxidant enzyme abundant in Clonorchis sinensis. In adult C. sinensis, 28GST was localized in tegumental syncytium, cytons, parenchyma, and sperm tails examined by immunoelectron microscopy. C. sinensis 28GST was earlier found to neutralize bioreactive compounds and to be rich in eggs. Accordingly, it is suggested that 28GST plays important roles in phase II defense system and physiological roles in worm fecundity of C. sinensis.  相似文献   

5.
Interactions between heavy metals, glutathione, glutathione S-transferase (GST), and glutathione reductase (GR) are being investigated by many working groups, but evaluation of the direct effect of Cd+ on these enzymes in vitro is lacking. We report here the effect of cadmium (10, 50, 100, 250 microM CdSO4) on partially purified enzymes from Calystegia sepium. Plants were grown under normal field conditions without metals and the enzymes were extracted by Tris buffer and partially purified by ammonium sulphate fractionation and gel filtration. Glutathione S-transferase activity was measured with different substrates, i.e., 1-chloro-2,4-dinitrobenzene (CDNB), p-nitrobenzylchloride (NBC), and the herbicide Fluorodifen. GST activity was significantly lower in leaf compared to stem, flower, and rhizome and the inhibitory effect of Cd was obtained with NBC and Fluorodifen substrates at 250 microM. There was no effect of Cd on GR activity up to 250 microM.  相似文献   

6.
We have previously reported that when garter snakesThamnophis sirtalis parietalis, a freeze tolerant species, were exposed to 5 h freezing at –2.5° C organs showed increases in the activities of anti-oxidant enzymes, especially catalase in skeletal muscle. This was interpreted to be an adaptation to deal with the potentially injurious postischemic situation of thawing. The present work analyzesin vitro oxidative inactivation of a possible target of postischemic-induced free radical damage, the secondary anti-oxidant defense glutathione-S transferase, and the protective role of endogenous catalase. Approximately 50% of GST activity from snake muscle homogenates was lost within 2 min after addition of H2O2 plus Fe(II) (0.4–2 mM) in media containing azide whereas addition of iron alone resulted in no damaging effects. The opposing effects of dimethyl sulfoxide and EDTA in modifying this process strongly suggested the involvement of ·OH radicals in the GST inactivation. A partial recovery of the activity was promoted by mercaptoethanol, indicating that sulphydryl groups oxidation participate in the mechanism of GST inactivation. Pre-incubation of the reaction media containing H2O2 caused protection of the GST activity only in the absence of azide, indicating that endogenous catalase modulates the extent of oxyradical damage. The protective pre-incubation effect was more efficacious when employing homogenates from lung and liver, organs that have higher catalase activities, as well as homogenates from freezing-exposed muscle (that show an 80% increase in catalase activity, compared with control). The protection against GST inactivation observed in muscle from frozen snakes demonstrates that increased anti-oxidant defenses during freezing exposure can be a key factor in controllingin vitro oxyradical damage. The implications for natural freeze tolerance are discussed.  相似文献   

7.
The safener-induced maize (Zea mays L.) glutathione S-transferase, GST II (EC 2.5.1.18) and another predominant isoform, GST I, were purified from extracts of maize roots treated with the safeners R-25788 (N,N-diallyl-2-dichloroacetamide) or R-29148 (3-dichloroace-tyl-2,2,5-trimethyl-1,3-oxazolidone). The isoforms GST I and GST II are respectively a homodimer of 29-kDa (GST-29) subunits and a heterodimer of 29 and 27-kDa (GST-27) subunits, while GST I is twice as active with 1-chloro-2,4-dinitrobenzene as GST II, GST II is about seven times more active against the herbicide, alachlor. Western blotting using antisera raised against GST-29 and GST-27 showed that GST-29 is present throughout the maize plant prior to safener treatment. In contrast, GST-27 is only present in roots of untreated plants but is induced in all the major aerial organs of maize after root-drenching with safener. The amino-acid sequences of proteolytic fragments of GST-27 show that it is related to GST-29 and identical to the 27-kDa subunit of GST IV.Abbreviations CDNB 1-chloro-2,4-dinitrobenzene - DEAE di-ethylaminoethyl - FPLC fast protein liquid chromatography - GSH reduced glutathione - GST glutathione S-transferase - GST-26 26-kDa subunit of maize GST - GST-27 27-kDa subunit of maize GST - GST-29 29-kDa subunit of maize GST - R-25788 safener N,N-diallyl-2-dichloroacetamide - R-29148 safener 3-dichloroacetyl-2,2,5-trimethyl-1,3-oxazolidone - RPLC reverse phase liquid chromatography We are grateful to M-M. Lay, ZENECA AG Products (formerly ICI Americas), Richmond, Calif., USA for providing [14C] R-25788. ZENECA Seeds in the UK is part of ZENECA Limited.  相似文献   

8.
9.
The effects of feeding ICRHa mice cyclic 12-, 8-, and 6-carbon compounds on glutathione S-transferase (GST) activity in the liver, intestinal mucosa, and the forestomach were determined. The compounds used for this study were 1,5,9-trans,trans,cis-cyclododecatriene, 1,2-trans-5,6-trans-9,10-cis-cyclododecatriene-1,2-oxide, cyclododecanol, cyclododecene oxide, cyclododecane, 1,5-cyclooctadiene, cyclooctene oxide, cyclohexene, and cyclohexene oxide. The unsaturated cyclic 12-carbon compounds elicited the greatest increase in GST activity. Thus, feeding 1,5,9-trans,trans,cis-cyclododecatriene increased this activity almost 4-fold in the livers and the intestinal mucosa of experimental animals. Cyclic 8-carbon compounds were less effective and feeding the cyclic 6-carbon compounds did not result in any significant increase in GST activity. None of the compounds elicited increased GST activity in the fore-stomach. Previous studies have shown that compounds inducing increased GST activity can protect against chemical carcinogens. It remains to be determined whether the compounds identified in the present investigation as inducers of this enzyme system will have such protective capacities.  相似文献   

10.
The influence of vanadium, an important dietary micronutrient, was evaluated on the cytosolic reduced glutathione (GSH) content and glutathione S-transferase (GST) activity in several rat target tissues. Supplementation of drinking water with vanadium at the level of 0.2 or 0.5 ppm for 4, 8, or 12 wk was found to increase the GSH level with a concomitant elevation in GST activity in the liver followed by small intestine mucosa, large intestine mucosa, and kidney. The results were almost dose-dependent and mostly pronounced with 0.5 ppm vanadium after 12 wk of its continuous supplementation. Neither the GSH level nor GST activity was significantly altered in forestomach and lung following vanadium supplementation throughout the study. The levels of vanadium that were found to increase the content of GSH and activity of GST in the liver, intestine, and kidney did not exert any toxic manifestation was evidenced from water and food consumption as well as the growth responses of the experimental animals. Moreover, these doses of vanadium did not impair either hepatic or renal functions as they did not alter the serum activities of glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), sorbitol dehydrogenase (SDH), as well as serum urea and creatinine levels. All these results clearly indicate that vanadium under the doses employed in our study has a significant inducing role on GSH content with a concurrent elevation in GST activity in the liver and specific extrahepatic tissues without any apparent sign of cytotoxicity. This attribute of vanadium may have a greater importance in terms of biotransformation and detoxification of xenobiotics, including carcinogens. In addition, since the ability to afford an increment in the endogenous GSH-GST pool by anticarcinogenic natural substances has been found to correlate with their activity to inhibit neoplastic transformation, the trace element vanadium may be considered as a novel anticancer agent.  相似文献   

11.
为深入探讨重金属镉(cadmium,Cd)的毒性效应,采用不同浓度氯化镉溶液对中华稻蝗Oxya chinensis Thunberg 4龄若虫进行急性染毒,对处理后24、48、72和96 h虫体内羧酸酯酶(CarE)和谷胱甘肽S-转移酶(GST)活性进行测定。结果表明,随着处理时间的延长,对照组和处理组CarE和GST活性均表现为先升后降的趋势。与对照组相比,以α-NA为底物时高浓度处理组(80 mg.L-1)CarE活性在处理后48 h被激活;以β-NA为底物时中浓度处理组(40 mg.L-1)CarE活性在72 h达到最高;以CDNB为底物时,低浓度处理组(20 mg.L-1)GST活性在24 h被激活达到最大值,之后降低。结果显示,中华稻蝗4龄若虫在Cd胁迫下,体内CarE和GST活性发生了变化,以此来抵御机体所受到的重金属毒害。  相似文献   

12.
Genes homologous to the auxin-inducible Nt103 glutathione S-transferase (GST) gene of tobacco, were isolated from a genomic library of Arabidopsis thaliana. We isolated a clone containing an auxin-inducible gene, At103-1a, and part of a constitutively expressed gene, At103-1b. The coding regions of the Arabidopsis genes were highly homologous to each other and to the coding region of the tobacco gene but distinct from the GST genes that have been isolated from arabidopsis thusfar. Overexpression of a cDNA clone in Escherichia coli revealed that the AT103-1A protein had GST activity.  相似文献   

13.
The activity of glutathione S-transferase (GST) decreased progressively in Schistosoma mansoni from mice treated with oltipraz (OPZ). However, the peroxidase activity of GST (selenium-independent) and selenium-dependent glutathione peroxidase was not affected by OPZ treatment. Purification and quantification of GST from worms after OPZ treatment indicated that the decrease in enzyme activity was greater than could be accounted for by the decrease in GST protein content. SDS-polyacrylamide gel electrophoresis followed by Western blot analysis with GST isoenzyme specific antisera revealed a slight decrease in the quantity of both 26 and 28 kDa GSTs. Fractionation of cytosolic GSTs from male S. mansoni by chromatofocusing resolved three major isoenzymes (SmI, II and III) and a minor form which eluted first from the column. SmI, II and III all had a molecular weight of about 28 kDa on SDS-polyacrylamide gel electrophoresis. However, on electrophoresis in the absence of SDS, the three GST forms exhibited different mobilities. The pattern of SmI, II and III was similar in untreated and OPZ-treated worms, but the activities of the isoenzymes from treated worms were lower. The results suggest that OPZ interacts with the GST isoenzymes SmI, II and III in a similar manner; thus, the effects are not isoenzyme specific. Taken together, these results suggest that OPZ and/or its metabolites interact directly with GST resulting in inhibition of activity and reduction in total enzyme protein. This mechanism may be important in the antischistosomal action of OPZ.  相似文献   

14.
Abstract:  An enzyme that possesses glutathione S -transferase (GST) activity was found in the fall webworm, Hyphantria cunea . The enzyme was purified to homogeneity for the first time by ammonium sulphate fractionation and affinity chromatography. The N-terminal sequence of the purified protein was similar to those of Sigma-class GSTs. The purified GST retained more than 75% of its original GST activity after incubation at pH 5–8. Incubation for 30 min at temperatures below 50°C scarcely affected the activity. The enzyme was able to catalyse the reaction of glutathione with 1-chloro-2,4-dinitrobenzene, a universal substrate for GST, as well as with 4-hydroxynonenal, a product of lipid peroxidation.  相似文献   

15.
The maleylpyruvate isomerase NagL from Ralstonia sp. strain U2, which has been structurally characterized previously, catalyzes the isomerization of maleylpyruvate to fumarylpyruvate. It belongs to the class zeta glutathione S-transferases (GSTZs), part of the cytosolic GST family (cGSTs). In this study, site-directed mutagenesis was conducted to probe the functions of 13 putative active site residues. Steady-state kinetic information for mutants in the reduced glutathione (GSH) binding site, suggested that (a) Gln64 and Asp102 interact directly with the glutamyl moiety of glutathione, (b) Gln49 and Gln64 are involved in a potential electron-sharing network that influences the ionization of the GSH thiol. The information also suggests that (c) His38, Asn108 and Arg109 interact with the GSH glycine moiety, (d) His104 has a role in the ionization of the GSH sulfur and the stabilization of the maleyl terminal carboxyl group in the reaction intermediate and (e) Arg110 influences the electron distribution in the active site and therefore the ionization of the GSH thiolate. Kinetic data for mutants altered in the substrate-binding site imply that (a) Arg8 and Arg176 are critical for maleylpyruvate orientation and enolization, and (b) Arg109 (exclusive to NagL) participates in kcat regulation. Surprisingly, the T11A mutant had a decreased GSH Km value, whereas little impact on maleylpyruvate kinetics was observed, suggesting that this residue plays an important role in GSH binding. An evolutionary trend in this residue appears to have developed not only in prokaryotic and eukaryotic GSTZs, but also among the wider class of cGSTs.  相似文献   

16.
The relationship between the activities of 3 cytosolic enzymes with aflatoxin biosynthesis in Aspergillus parasiticus cultured under different conditions has been investigated in order to find out the role of each enzyme in aflatoxin biosynthesis. Basically the activity of isocitrate dehydrogenase (IDH) was higher in non-toxigenic strains as compared to its counterpart toxigenic fungi (p < 0.05). In contrast, the activities of fatty acid synthase (FAS) as well as glutathione S-transferase (GST) were higher (P < 0.05) in toxigenic strains than that of the non-toxigenic fungi. Aflatoxin production was inhibited in fungi grown in presence of various concentrations of neem leaf extract. Aflatoxin was at its lowest level (>90% inhibition) when the concentration of neem extract was adjusted to 50% (v/v). No significant changes in FAS and IDH activities were observed when aflatoxin synthesis was under restraints by neem (Azadirachta indica) leaf extract. During a certain period of time of culture growth, when aflatoxin production reached to its maximum level, the activity of FAS was slightly induced in the toxigenic strains fed with a low concentration (1.56% v/v) of the neem leaf extract. At the time (96 h) when aflatoxin concentration reached to its maximum levels, the activity of GST in the toxigenic fungi was significantly higher (i.e., 7–11 folds) than that of non-toxigenic strains. The difference was highest in mycelial samples collected after 120 h. However unlike FAS and IDH, GST was readily inhibited (67%) in mycelia fed with 1.56% v/v of the neem extract. The inhibition reached to maximum of 80% in samples exposed to 6.25–12.5% of the extract. These results further substantiate previous finding that there is a positive correlation between GST activity and aflatoxin production in fungi.This revised version was published online in October 2005 with corrections to the Cover Date.  相似文献   

17.
Exposure of animals to cadmium (Cd) (25 mg kg-1 body wt day-1) for 10 weeks resulted in preferential accumulation of the metal in liver and kidney. Cd accumulation concomitantly increased zinc (Zn) concentration in both the organs. However, significant decrease in copper level was observed in liver, whereas kidney showed increase in copper (Cu) level. Cd exposure resulted in decreased total GST activity in liver (63%) and kidney (41%) as compared to control group monkeys on normal diet (group I). On isoelectric focusing (IFP) control liver GST segregated into thirteen isoenzymes, while in Cd-treated experimental animals (group II) liver GST resolved into nine isoenzymes. Similarly kidney GST from control animals separated into seven isoenzymes as compared to four isoenzymes from Cd-treated animals. Kinetic analysis showed that Cd exposure did not alter the affinity constant (Km) of GST for GSH and CDNB whereas maximal velocity (Vmax) for these substrates decreased as compared to controls in both the organs, indicating inhibition in GST synthesis by Cd. Cd resulted in a noncompetitive type of inhibition with respect to GSH in vitro. On isoelectric focussing GST of liver and kidney in group II resolved into nine and four isoenzymes as compared to thirteen and seven in group I, showing loss of four basic isoenzymes in case of liver and three isoenzymes in case of kidney. Monkey liver and kidney expressed all the three classes of GST isoenzymes i.e. , µ and , which were serologically identical to human , µ and GSTs. (Mol Cell Biochem 166: 55-63, 1997)  相似文献   

18.
The bacterial expression and purification of human pi class glutathione S-transferase (hGST P1-1) as a hexahistidine-tagged polypeptide was performed. The expression plasmid for hGST P1-1 was constructed by ligation of the cDNA which codes for the protein into the expression vector pET-15b. The expressed protein was purified by either glutathione or metal (Co(2+)) affinity column chromatography, which produced the pure and fully active enzyme in one step with a yield of more than 30 mg/liter culture. The activity of the purified protein was 130 units mg(-1) from the GSH affinity column and 112 units mg(-1) from the Co(2+) affinity column chromatography. The purity of the protein was assessed by electrospray ionization mass spectrometry and size-exclusion chromatography. It showed that the real molecular weight of the hexahistidine-tagged hGST P1-1 polypeptide chain agreed with the calculated value and that the purified protein eluted as an apparent homodimer on the gel filtration column. Our expression system allows the expression and purification of active hexahistidine-tagged hGST P1-1 in high yield with no need of removal of the hexahistidine tag and gives pure protein in one purification step allowing further study of this enzyme.  相似文献   

19.
Antioxidant enzymes play important roles in the protection against oxidative damage caused by environmental pollutants by scavenging high levels of reactive oxygen species and have been quantified as oxidative stress markers. However, combining mRNA expressions of genes coding for detoxification enzymes along with enzyme activities will be more useful biomarkers of stress. Therefore, in this study the cDNA of the catalase gene from the aquatic midge, Chironomus riparius (CrCAT) was sequenced using 454 pyrosequencing. The 2139 bp CrCAT cDNA included an open reading frame of 1503 bp encoding a putative protein of 500 amino acids with a predicted molecular mass of 56.72 kDa. There was an 18 bp 5’ and a long 618 bp 3' untranslated region with a polyadenylation signal site (AATAAA). The deduced amino acid sequence of CrCAT contained several highly conserved motifs including the proximal heme–ligand signature sequence RLFSYNDTX and the proximal active site signature FXRERIPERVVHAKGXGA. A comparative analysis showed the presence of conserved amino acid residues and all of the catalytic amino acids (His70, Asn143, and Tyr353) were conserved in all species. The CrCAT contained three potential glycosylation sites and a peroxisome targeting signal of ‘AKM’. The mRNA was detected using RT-PCR at all developmental stages. The time-course expression of CrCAT was measured using quantitative real-time PCR after exposure to different concentration and durations of Paraquat (PQ), cadmium chloride (Cd) and nonylphenol (NP). The expression of CrCAT was significantly up regulated on exposure to 50 and 100 mg/L PQ for 12 and 24 h. Among the different concentrations and durations of Cd tested, significantly highest level of expression for CrCAT mRNA and catalase enzyme activity was observed on exposure to 10 mg/L for 24 h. In the case of NP, the highest level of CrCAT expression was observed after exposure to 100 μg/L for 24 h. The expression profiles of three selected C. riparius glutathione S-transferase genes (CrGSTs) viz. CrGSTdelta3, CrGSTsigma4 and CrGSTepsilon1 was also studied on exposure to NP and were up or down regulated at different time points and concentrations. Significantly highest level of expression for CrGSTdelta3 was observed after 48 h and for CrGSTsigma4 and CrGSTepsilon1 after 24 h exposure to 100 μg/L of NP. The results show that CrGSTs and CrCAT could be used as potential biomarkers in C. riparius for aquatic ecotoxicological studies.  相似文献   

20.
Glutathione S-transferases (GSTs; EC 2.5.1.18) have recently been proposed to form one large group among the auxin-induced proteins. However. the properties and regulation of such auxin-responsive GSTs in the plant still await detailed investigation. In this study, a 2,4-dichloro-phenoxyacetic acid (2,4-D)-inducible GST isozyme from soybean ( Glycine max [L.] Merr. cv. Williams) was purified to near homogeneity by anion-exchange and affinity chromatography on S-hexylglutathione agarose. The native enzyme had a molecular mass of 49 kDa, as determined by gel filtration, and consisted of 26-kDa subunits. The purified GST conjugated glutathione to 1-chloro-2,4-dinitrobenzene and to the herbicide metolachlor, but not to the other GST substrates atrazine. fluorodifen or trans-cinnamic acid. The N-termmal amino acid sequence shared significant homology with the deduced polypeptide sequences of two 2,4-D-inducible genes from tobacco, par A and CNT107 . The levels of the 26-kDa GST subunit protein in soybean hypocotyls were analysed by immunoblotting. At micromolar concentrations, 2,4-D induced a transient increase in net accumulation of GST, whereas indole-3-acetic acid or I-naphthaleneacetic acid did not increase the GST levels. Known inhibitors of polar auxin transport, including 2.3.5-tri-iodobenzoic acid. N-I-naphthylphthalamic acid and analogues thereof, differed widely in their ability to elicit GST protein accumulation. It is concluded that the induction of soybean GST by 2,4-D and by some of the auxin transport inhibitors is not related to auxin activity or to changes in the endogenous auxin levels.  相似文献   

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