Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.5.1.18 (glutathione S-transferase)
 22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Wistar male rats received polysynthetic diets incorporating lard or fish of different oxidation degree as the sourse of fat. The feeding lasted 4 weeks. In the liver of rats on fish oil diet the activity of the enzymes of xenobiotic metabolism phase I (monooxigenase system, epoxide hydrolase, carboxyl esterase) and phase II (native and activated UDP-glucuronosyl transferase, glutathione transferase) located both in microsoma membranes and in cytozole was higher than in the animals on lard diet. The enzyme activity was much more enhanced in the use of oxidated fish oil. No effect of fish oil on serum and lysosome enzyme activity and rat hepatic structure was found.
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PMID:[Effects of the degree of fish oil oxidation on the state of xenobiotic metabolism enzymes]. 781 22

Baseline entomological surveillance was carried out in a rural area of The Gambia during the rainy season in 1988, one year before the implementation of a malaria control programme using insecticide-impregnated nets and targeted chemoprophylaxis in villages with a primary health care (PHC) system. Mosquito collections took place in 6 pairs of settlements each with untreated bed nets; within each pair there was a large PHC village with a resident village health worker (VHW) and traditional birth attendant (TBA) and a smaller non-PHC village without either a VHW or a TBA. The most common vectors in the study area were Anopheles gambiae sensu stricto and, to a lesser extent, An. arabiensis. These mosquitoes were found in appreciable numbers for at least 4 months of the year (geometric mean/bedroom/night = 32.5, 95% confidence interval 18.2-57.3). Numbers of mosquitoes collected in PHC villages or non-PHC villages were not significantly different. Greater numbers of mosquitoes were found in villages closer to the River Gambia than in those further away. Evidence for DDT resistance due to elevated glutathione S-transferase activity was found in one of the 12 villages, but there was no evidence of resistance to organophosphate or carbamate insecticides as suggested by the low esterase levels and carbamate sensitive acetylcholinesterase.
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PMID:A malaria control trial using insecticide-treated bed nets and targeted chemoprophylaxis in a rural area of The Gambia, west Africa. 3. Entomological characteristics of the study area. 821 5

Thirty strains of Blattella germanica (L.) reported to be pyrethroid resistant were collected from three continents. Greater than 2-fold resistance to the pyrethroids cyfluthrin, fenvalerate, cypermethrin, and lambda cyhalothrin appeared in 15 of these strains. Twelve of these strains were also resistant to chlorpyrifos and propoxur. All the field strains tested were heterogeneous with regard to resistance. Possible resistance mechanisms detected in these populations included elevated levels of cytochrome P450, general esterase and glutathione S-transferase, and nerve insensitivity (kdr-type resistance). The elevated esterases and oxidase-based resistance were the most prevalent; 11 and 10 strains, respectively, had evidence of these mechanisms. Resistance was synergized by piperonyl butoxide in some strains. In some strains, elevated esterases, although present, were primarily correlated with organophosphate resistance. Pyrethroid insecticides may still be effective against many of these populations because of the low levels of resistance detected. However, potential exists for more serious resistance problems to develop if only pyrethroids are used. Because many of these strains are already resistant to organophosphorus and carbamate insecticides, prospects for the future chemical control of these populations must be carefully considered.
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PMID:Pyrethroid resistance in German cockroaches (Dictyoptera: Blattelidae): resistance levels and underlying mechanisms. 829 21

The enzymes acetylcholinesterase, glutathione S-transferase (GST), glucose 6-phosphate dehydrogenase (G6PD), and general esterases were assayed in four strains of Aedes aegypti mosquitoes aged between 1 and 30 days. Microtitre plate methods were used to assay activity in the homogenates of individual mosquitoes. The levels of GST and G6PD declined with the age of the mosquitoes, while the activity for the other enzymes remained constant. Soluble protein content was also found to decline with mosquito age in all the strains. Insecticide bioassays showed that two strains (Trinidad and Virtudes) of Ae. aegypti were resistant to DDT, deltamethrin and malathion, whereas two other strains (Bangkok and Indian) were susceptible to all four classes of insecticides tested. Higher esterase activity levels in the resistant compared to the susceptible strains were assumed to be the cause of organophosphate resistance. The combination of DDT and deltamethrin resistance in two strains with normal GST and G6PD characteristics suggests that a kdr-type nerve insensitivity mechanism may be involved.
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PMID:Changes in enzyme titres with age in four geographical strains of Aedes aegypti and their association with insecticide resistance. 843 83

Using a subtractive hybridization method, we have cloned cDNAs corresponding to 10 different mRNAs which share the property of being expressed in the intestine of adult but not baby rabbits. Four could be identified as coding for previously known gene products (sucrase-isomaltase, a glutathione S-transferase, a cytochrome P450, and a long form of ferritin mRNA), while six code for previously unknown proteins. One clone, AdRab-B, codes for a protein of 1458 amino acids, including (i) a putative signal sequence at the NH2 terminus, (ii) four internal repeats, 308-346 amino acids in length, (iii) a hydrophobic stretch near the COOH terminus, which represents a potential membrane anchor, and (iv) a short hydrophilic stretch at the very COOH terminus. The corresponding protein was studied with the aid of antibodies prepared against polypeptides expressed from segments of the cDNA in Escherichia coli. The protein was shown to be proteolytically processed in the intestine (but not when expressed in COS cells) and to be targeted to the brush border membrane of the enterocytes. Finally, the protein was found to have esterase and phospholipase A/lysophospholipase activity.
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PMID:Messenger RNAs expressed in intestine of adult but not baby rabbits. Isolation of cognate cDNAs and characterization of a novel brush border protein with esterase and phospholipase activity. 850 24

Etofenprox is a non-ester pyrethroid insecticide with comparable toxicity and a similar mode of action to other pyrethroids. Cross-resistance studies on mosquitoes showed no effect of carboxylesterase, elevated esterase, altered acetylcholinesterase or glutathione S-transferase-based resistance mechanisms on etofenprox toxicity, when compared to standard susceptible strains of Anopheles and Culex. Cross-resistance to etofenprox occurred in a pyrethroid-resistant strain of Culex quinquefasciatus with both oxidase and 'kdr'-like resistance mechanisms. Dose-response data for susceptible mosquito strains suggest that, in standard W.H.O. susceptibility tests of adult mosquitoes, appropriate discriminating concentrations of etofenprox for detection of resistance would be 0.1% for Culex and 0.25% for Anopheles.
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PMID:Efficacy of etofenprox against insecticide susceptible and resistant mosquito strains containing characterized resistance mechanisms. 854 96

Ultrastructural, stereological and biochemical alterations in isolated hepatocytes and the permanent fibrocyte-like cell line R1 from rainbow trout (Oncorhynchus mykiss) exposed to 0, 0.2, 2 and 20 mg/l of the phosphorodithioate pesticide disulfoton (Solvirex, O,O-diethyl S-2-ethylthioethyl phosphorodithioate) for up to 5 days were investigated. In both R1 cells and isolated hepatocytes, distinct dose- and time-dependent morphological alterations including diminished amounts of heterochromatin, proliferation of lysosomal elements, dilation and vesiculation of endoplasmic reticulum cisternae, induction of concentric membrane whorls and an increased amount of lipid droplets could be detected at concentrations of > or = 2 mg/l (R1 cells) and > or = 0.2 mg/l disulfoton (hepatocytes). Additional effects in isolated hepatocytes comprised marginalization of heterochromatin, myelin-like structures attached to mitochondrial membranes, formation of ring-shaped mitochondria, proliferation of smooth endoplasmic reticulum, reduction of rough endoplasmic reticulum, induction of ring-shaped Golgi cisternae, glycogen depletion and occurrence of glycogenosomes. Structural changes in isolated hepatocytes could be correlated to suppression of lactate dehydrogenase, glucose-6-phosphate dehydrogenase, alanine aminotransferase, malic enzyme, esterase as well as glutathione S-transferase, but to a stimulation of 7-ethoxycoumarin-O-deethylase and the rate of lipid peroxidation at concentrations > or = 0.01 mg/l disulfoton. Comparison with data from in vivo experiments with rainbow trout indicate the suitability of in vitro techniques for the evaluation of the toxicological potential of a wide range of ecotoxicologically relevant substances.
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PMID:Cytological and biochemical response of R1 cells and isolated hepatocytes from rainbow trout (Oncorhynchus mykiss) to subacute in vitro exposure to disulfoton. 891 71

After 4 days of acetysal treatment (160 mg/kg body weight orally), the following were established: a higher acute toxicity of acetysal, an inducing effect on amidopyrin N-demethylase and analgin N-demethylase activity and increases in cytochrome P-450 and cytochrome b5 content. Aniline hydroxylase activity decreased, thiopental sleeping time was prolonged and UDP-glucuronyltransferase activity was not changed. Dexamethasone, at a dose of 5 mg/kg body weight p.o. for 4 days, did not change acetysal acute toxicity but at a dose of 100 mg/kg i.p. increased it. Thiopental sleeping time was shortened by dexamethasone (100 mg/kg i.p.) but was not changed by dexamethasone at 5 mg/kg p.o., alone or in combination. Dexamethasone at 5 mg/kg increased analgin N-demethylase and UDP-glucuronyltransferase activities, did not change cytochrome P-450 content and decreased aniline hydroxylase activity. The combination with 5 mg/kg dexamethasone increased the activity of amidopyrin N-demethylase, analgin N-demethylase and UDP-glucuronyltransferase and decreased those of amitriptyllin N-demethylase and aniline hydroxylase and cytochrome P-450 content. Ethylmorphine N-demethylase, benzphetamine N-demethylase, NADPH-cytochrome c reductase and glutathione S-transferase activities were not affected significantly by acetysal, dexamethasone or their combination. Hepatic carboxyl esterase was depressed by dexamethasone (5 mg/kg) and was increased by the combination. Lipid peroxidation was not changed by dexamethasone (5 mg/kg) but was decreased by acetysal and the combination.
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PMID:Effects of acetysal, dexamethasone and their combination on drug metabolizing enzyme systems in rat liver microsomes. 898 33

Albicidin phytotoxins are pathogenicity factors in a devastating disease of sugarcane known as leaf scald, caused by Xanthomonas albilineans. A gene (albD) from Pantoea dispersa has been cloned and sequenced and been shown to code for a peptide of 235 amino acids that detoxifies albicidin. The gene shows no significant homology at the DNA or protein level to any known sequence, but the gene product contains a GxSxG motif that is conserved in serine hydrolases. The AlbD protein, purified to homogeneity by means of a glutathione S-transferase gene fusion system, showed strong esterase activity on p-nitrophenyl butyrate and released hydrophilic products during detoxification of albicidins. AlbD hydrolysis of p-nitrophenyl butyrate and detoxification of albicidins required no complex cofactors. Both processes were strongly inhibited by phenylmethylsulfonyl fluoride, a serine enzyme inhibitor. These data strongly suggest that AlbD is an albicidin hydrolase. The enzyme detoxifies albicidins efficiently over a pH range from 5.8 to 8.0, with a broad temperature optimum from 15 to 35 degrees C. Expression of albD in transformed X. albilineans strains abolished the capacity to release albicidin toxins and to incite disease symptoms in sugarcane. The gene is a promising candidate for transfer into sugarcane to confer a form of disease resistance.
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PMID:The gene for albicidin detoxification from Pantoea dispersa encodes an esterase and attenuates pathogenicity of Xanthomonas albilineans to sugarcane. 927 38

A high level of DDT resistance and low levels of resistance to organophosphorus, carbamate and pyrethroid insecticides were detected by discriminating dose assays in field populations of Anopheles albimanus in Chiapas, southern Mexico, prior to a large-scale resistance management project described by Hemingway et al. (1997). Biochemical assays showed that the DDT resistance was caused by elevated levels of glutathione S-transferase (GST) activity leading to increased rates of metabolism of DDT to DDE. The numbers of individuals with elevated GST and DDT resistance were well correlated, suggesting that this is the only major DDT resistance mechanism in this population. The carbamate resistance in this population is conferred by an altered acetylcholinesterase (AChE)-based resistance mechanism. The level of resistance observed in the bioassays correlates with the frequency of individuals homozygous for the altered AChE allele. This suggests that the level of resistance conferred by this mechanism in its heterozygous state is below the level of detection by the WHO carbamate discriminating dosage bioassay. The low levels of organophosphate (OP) and pyrethroid resistance could be conferred by either the elevated esterase or monooxygenase enzymes. The esterases were elevated only with the substrate pNPA, and are unlikely to be causing broad spectrum OP resistance. The altered AChE mechanism may also be contributing to the OP but not the pyrethroid resistance. Significant differences in resistance gene frequencies were obtained from the F1 mosquitoes resulting from adults obtained by different collection methods. This may be caused by different insecticide selection pressures on the insects immediately prior to collection, or may be an indication that the indoor- and outdoor-resting A. albimanus collections are not from a randomly mating single population. The underlying genetic variability of the populations is currently being investigated by molecular methods.
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PMID:Resistance management strategies in malaria vector mosquito control. Baseline data for a large-scale field trial against Anopheles albimanus in Mexico. 973 93


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