Glutathione S-transferases M1,T1 genotypes and the risk of gastric cancer:A case-control study

AIM: Glutathione S-transferases (GSTs) are involved in the detoxification of many potential carcinogens and appear to play a critical role in the protection from the effects of carcinogens. The contribution of glutathione S-transferases M1 and T1 genotypes to susceptibility to the risk of gastric cancer and their interaction with cigarette smoking are still unclear. The aim of this study was to determine whether there was any relationship between genetic polymorphisms of GSTT1 and GSTT1 and gastric cancer. METHODS: A population based case-control study was carried out in a high-risk area, Changle County, Fujian Province, China. The epidemiological data were collected by a standard questionnaire and blood samples were obtained from 95 incidence gastric cancer cases and 94 healthy controls. A polymerase chain reaction method was used to detect the presence or absence of the GSTT1 and GSTT1 genes in genomic DNA. Logistic regression model was employed in the data analysis. RESULTS: An increase in risk for gastric cancer was found among carriers of GSTT1 null genotype. The adjusted odds ratio (OR) was 2.63 95% Confidence Interval (95% CI) 1.17-5.88, after controlling for age, gender, cigarette smoking, alcohol drinking, and fish sauce intake. The frequency of GSTT1 null genotype in cancer cases (43.16%) was not significantly different from that in controls (50.00%). However, the risk for gastric cancer in those with GSTT1 null and GSTT1 non-null genotype was significantly higher than in those with both GSTT1 and GSTT1 non-null genotype (OR = 2.77, 95% CI 1.15-6.77). Compared with those subjects who never smoked and had normal GSTT1 genotype, ORs were 1.60 (95% CI:0.62-4.19) for never smokers with GSTT1 null type, 2.33 (95% CI 0.88-6.28) for smokers with normal GSTT1, and 8.06 (95% CI 2.83-23.67) for smokers with GSTT1 null type. CONCLUSIONS: GSTT1 gene polymorphisms may be associated with genetic susceptibility of stomach cancer and may modulate tobacco-related carcinogenesis of gastric cancer.

Purification and characterization of rat testicular glutathione S-transferases:role in the synthesis of eicosanoids

Aim: Purification of glutathione S-transferases (GSTs) from rat testis; separation and identificationunits and their role in eicosanoid biosynthesis. Methods: Purification of mt testicular GSTs by affit?phy, employing S-hexylglutathione-linked epoxy-activated Sepharose 6B column and separation of indiby reverse phase-high pressure liquid chromatography (RP-HPLC). Characterization of affinity purified,um dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Westem blot analysis. The roGSTs in eicosanoid biosynthesis was determined by incubating GSTs with 5, 6-Leukotriene A_4Me (prostaglandin H_2 (PGH_2) and analyzing the products formed on HPLC/TLC. Results: The present stumajority of rat testicular GSTs are of Y_b size (60%) with molecular weight of 27 kDa. The most preunits, however, are GST Y_(n2) (27% ), followed by GST Y_c (24% ) and GST Y_(nl) (20%). These testiculavery high Leukotriene C_4 (LTC_4) synthase activity with 5, 6-Leukotriene A4Me (LTA_4Me) as theprostaglandin D (PGD) synthase activity with prostaglandin H_2 (PGH_2) as the substrate. Conclusion:testicular GSTs are Y_b sized and are involved in the synthesis of eicosanoids like LTC_4 and PGD_2.(Asian J Androl 2000 Dec; 2: 277-282)

Novel functional association of rat testicular membrane-associated cytosolic glutathione S transferases and cyclooxygenase in vitro

Aim:To analyze the role of cytosolic glutathione S-transferases (cGSTs) and membrane-associated cytosolic GSTs (macGSTs) in prostaglandin biosynthesis and to evaluate the possible interaction between glutathione S-transferases (GSTs) and cyclooxygenase (COX) in vitro.Methods:SDS-PAGE analysis was undertaken for characterization of GSTs,thin layer chromatography (TLC) to monitor the effect of GSTs on prostaglandin biosynthesis from arachi- donic acid (AA) and spectrophotometric assays were done for measuring activity levels of COX and GSTs.Results: SDS-PAGE analysis indicates that macGSTs have molecular weights in the range of 25-28 kDa.In a coupled assay involving GSTs,arachidonic acid and cyclooxygenase-1,rat testicular macGSTs produced prostaglandin E2 and F2~, while the cGSTs caused the generation of prostaglandin D2,E2 and F_(2α).In vitro interaction studies on GSTs and COX at the protein level have shown dose-dependent inhibition of COX activity by macGSTs and vice versa.This effect, however,is not seen with cGSTs.The inhibitory effect of COX on macGST activity was relieved with increasing concentrations of reduced glutathione (GSH) but not with 1-chloro 2,4-dinitrobenzene (CDNB).The inhibition of COX by macGSTs,on the other hand,was potentiated by glutathione.Conclusion:We isolated and purified macGSTs and cGSTs from rat testis and analyzed their involvement in prostaglandin biosynthesis.These studies reveal a revers- ible functional interaction between macGSTs and COX in vitro,with possible interactions between them at the GSH binding site of macGSTs.

Comparative Studies of Substrate and Inhibitor Specificity of Glutathione S-Transferases in Six Tissues of Oxya chinensis(Thunberg)(Orthoptera:Acrididae)

Specific activity, substrate specificity, and kinetic parameters （Km and Vmax） of glutathione S-transferases （GSTs） towards three substrates, 1-chloro-2,4-dinitrobenzene （CDNB）, 1,2-dichloro-4-nitrobenzene （DCNB）, and p-nitrobenzene chloride （pNBC） were investigated in six tissues （foregut, midgut, hindgut, fat body, hemolymph, and muscle） of Oxya chinensis. In addition, the inhibition in vitro （ethacrynic acid, and Cibacron Blue 3GA） of Oxya chinensis in the six tissues was also investigated. Glutathione S-transferase activity was detected in all the six tissues examined. The rank order of GST activities towards CDNB was fat body 〉 midgut 〉 hindgut 〉 muscle 〉 foregut 〉 hemolymph both in females and males. Glutathione S-transferase activities in the fat body in females and males were 1.3- to 10.4-fold and 1.1- to 10.0- fold higher than those in the other tissues. The rank order of GST activities towards the other substrates changed slightly. From these results, it was inferred that GSTs in the fat body and midgut played important roles in detoxifying xenobiotics including insecticides and plant allelochemicals in O. chinensis. In the three substrates examined, CDNB seemed to be the best substrate, followed by pNBC and DCNB. The kinetic parameters of GSTs were different among the six tissues. This suggested that GSTs in different tissues have various affinities and catalytic efficiency to substrates. In vitro inhibition study showed that the median inhibition concentration （IC50） values of the two inhibitors to GSTs from the six tissues were different. The results suggested that the two inhibitors have different inhibition potency to GSTs from the different tissues. The observed changes in kinetic parameters and inhibition in vitro among the six tissues of the insect might suggest that the number and structure of isoenzymes and their rate of expression varied for the different tissues.

Prognostic Significance of Comparison of Clinical Indicators with Manifestations of Genetic Polymorphism of Glutathione-S-Transferases in Non-Small Cell Lung Cancer

The article presented the results of comparison of polymorphic variants of the genes GSTM1, GSTT1, GSTP1 and clinical manifestations of non-small cell lung carcinoma. The association of the genotype GSTT1 (del) with the risk of developing squamous cell lung cancer has been revealed (OR = 2.54 CI: 1.13 - 5.72, p = 0.035). Analysis of patient survival rate (n = 173) in groups of various histological types of lung cancer showed that in the group of squamous cell lung cancer (n = 91) in patients with genotype GSTT1 (del), the survival rate median was significantly higher—84 months (95% CI 12.4 - 155.7) than in patients with the genotype GSTT1 (+)—36 months (95% CI 25.2 - 46.8, p = 0.045). In contrast, in the adenocarcinoma group (n = 82), the survival rate median in patients with the genotype GSTT1 (del) was 19 months. (95% CI 6.2 - 33.5), and in patients with genotype GSTT1 (+)—67 months (95% CI 50.1 - 84.0), which is the basis for continuing this comparison in an additional group of testees, as the sampling did not achieve the reliability of p = 0.12. Hypothetically, these differences may be due to differences in the gender composition of squamous cell lung cancer and adenocarcinoma and the involvement of GST enzymes in the metabolism of estrogens in adenocarcinoma in women and other hormonal background and reactivity of the male body with squamous cell carcinoma. Further research and subsequent analysis of the results will be aimed at confirming this hypothesis.

Comparative study on glutathione transferases of rat brain and testis under the stress of phenobarbitol and β-methylcholanthrene

A comparative study was made on the tissue specific expression of glutathione transferases (GST) in brain and testis after exposure of rat to phenobarbitol (PB) and β-methylcholanthrene (MC). Glutathione transferases, a family of multifunctional proteins are involved in intracellular transport processes and in detoxication of electrophilic xenobiotics by catalyzing reactions such as conjugation, isomerization, reduction and thiolysis. On purification, the yield of GST proteins by affinity chromatography was 39% in testis and 32% in brain. The affinity purified testis GSTs were resolved by chromatofocusing into six anionic and four cationic isozymes, and in brain glutathione transferases were resolved into four anionic and three cationic isozymes, suggesting the presence of multiple isozymes with Yc, Yb, Yβ and Yδ in both of them. In testis and brain, these isozymes at identical pI values showed variable functions with a battery of substrates and the cationic isozymes of brain and testis showed identical properties in CHP (cumene hydroperoxide) at pH values of above 7.0. Substrate specificity studies and immunoblot analysis of testis and brain proteins revealed that they play a predominant role in the detoxication of phenobarbitol or β-methylcholanthrene. Expression of the isozymes in testis and brain on exposure to PB and MC indicated elevated subunit variation. In both testis and brain, Yδ of π class was expressed on PB treatment and Yc of α class and Yβ of μ class was expressed in MC treated testis and only Yc was predominantly expressed in MC treated brain. Thus these subunits expression is considered as markers for carcinogenesis and specific to chemical toxicity under phenobarbitol and β-methylcholanthrene stress.

Mapping the Antigenic Peptides of Sm26/2 in Glutathione S-Transferases of Schistosoma Mansoni

Six antigenic peptides of Sm26/2 glutathione S-transferase of schistosoma mansoni have been predicted according to their hydrophilicity, flexibility, accessibility, charge distribution and beta-turn in the secondary structure by the determination of its primary structure, and synthesized by solid phase method. Two of them showed good antigenicity by Dot-ELISA. They would be candidate peptides of synthetic anti-schistosomal vaccine.

Expression of Presenilin-2 and Glutathione S Transferase π and Their Clinical Significance in Breast Infiltrating Ductal Carcinoma

To investigate the expressions of presenilin-2 (PS2) and glutathione Stransferase π (GSTπ) and their roles in prognosis and therapy of breast infiltrating ductalcarcinoma. Methods: The paraffin-embedded specimens of 210 patients with breast infiltrating ductalcarcinoma were examined by using LSAB immunohistochemistry for the expression of PS2 and GSTπ.Results: The expression rate of PS2 and GSTπ was 49.5% (104/210) and 48.1% (101/210) respectively.The 5-year and 10-year postoperative survival rates in 4 groups, from high to low, were group 1 (PS2positive expression/GSTπ negative expression), group 2 (PS2 positive expression/GSTπ positiveexpression), group 3 (PS2 negative expression/GSTπ negative expression) and group 4 (PS2 negativeexpression/GSTπ positive expression) in turn. Conclusion: The prognosis of the group 1 was thebest, followed by the group 2, group 3 and group 4 in turn. These results suggested that thereasonable use of endocrinotherapy and chemotherapy for patients with breast infiltrating ductalcarcinoma is necessary.

Gamma-glutamyl transferase 5 overexpression in cerebrovascular endothelial cells improves brain pathology,cognition,and behavior in APP/PS1 mice

In patients with Alzheimer’s disease,gamma-glutamyl transferase 5(GGT5)expression has been observed to be downregulated in cerebrovascular endothelial cells.However,the functional role of GGT5 in the development of Alzheimer’s disease remains unclear.This study aimed to explore the effect of GGT5 on cognitive function and brain pathology in an APP/PS1 mouse model of Alzheimer’s disease,as well as the underlying mechanism.We observed a significant reduction in GGT5 expression in two in vitro models of Alzheimer’s disease(Aβ_(1-42)-treated hCMEC/D3 and bEnd.3 cells),as well as in the APP/PS1 mouse model.Additionally,injection of APP/PS1 mice with an adeno-associated virus encoding GGT5 enhanced hippocampal synaptic plasticity and mitigated cognitive deficits.Interestingly,increasing GGT5 expression in cerebrovascular endothelial cells reduced levels of both soluble and insoluble amyloid-βin the brains of APP/PS1 mice.This effect may be attributable to inhibition of the expression ofβ-site APP cleaving enzyme 1,which is mediated by nuclear factor-kappa B.Our findings demonstrate that GGT5 expression in cerebrovascular endothelial cells is inversely associated with Alzheimer’s disease pathogenesis,and that GGT5 upregulation mitigates cognitive deficits in APP/PS1 mice.These findings suggest that GGT5 expression in cerebrovascular endothelial cells is a potential therapeutic target and biomarker for Alzheimer’s disease.

Alterations of glutathione S-transferase and matrix metalloproteinase-9 expressions are early events in esophageal carcinogenesis

AIM: To investigate the role of glutathione S-transferase (GST) and matrix metalloproteinase-9 (MMP-9) expres-sions in the development and progression of reflux es-ophagitis-Barrett’s metaplasia-dysplasia-adenocarcinoma sequence in the esophagus.METHODS: GST and MMP-9 expressions were analyzed in 51 paraffin-embedded tissue samples by immunohisto-chemistry including patients with reflux esophagitis (n = 7), Barrett’s metaplasia (n = 14), Barrett and esophagi-tis (n = 8), Barrett and dysplasia (n = 7), esophageal adenocarcinoma (n = 8) and a control group without any histological changes (n = 7). Immunostaining was determined semiquantitatively. Statistical analysis with one-way ANOVA, LSD test and correlation analysis were performed. P value of < 0.05 was considered significant.RESULTS: GST expression was significantly higher while MMP-9 expression was significantly lower in control group compared to Barrett’s metaplasia and the other groups. No major changes were observed between Bar-rett, esophagitis, and Barrett and concomitant esophagi-tis. Barrett and concomitant dysplasia, and adenocarci-noma revealed a significant lower expression of GST and higher levels of MMP-9 compared to all other groups. Adenocarcinoma showed almost no expression of GST and significantly higher levels of MMP-9 than Barrett and concomitant dysplasia. Alterations of GST and MMP-9 were inversely correlated (r = - 0.82).CONCLUSION: Decreased GST and increased ex-pression of MMP-9 in Barrett’s metaplasia-dysplasia-adenocarcinoma sequence as compared to normal tissue suggest their association with esophageal tumorigenesis. Loss of GST and gain of MMP-9 in Barrett with dyspla-sia compared to non-dysplastic metaplasia indicate that these alterations may be early events in carcinogenesis. Quantification of these parameters in Barrett’s esopha-gus might be useful to identify patients at higher risk for progression to cancer.

Response of Glutathione and Glutathione S-transferase in Rice Seedlings Exposed to Cadmium Stress

A hydroponic culture experiment was done to investigate the effect of Cd stress on glutathione content （GSH） and glutathione S-transferase （GST, EC 2.5.1,18） activity in rice seedlings. The rice growth was severely inhibited when Cd level in the solution was higher than 10 mg/L. In rice shoots, GSH content and GST activity increased with the increasing Cd level, while in roots, GST was obviously inhibited by Cd treatments, Compared with shoots, the rice roots had higher GSH content and GST activity, indicating the ability of Cd detoxification was much higher in roots than in shoots. There was a significant correlation between Cd level and GSH content or GST activity, suggesting that both parameters may be used as biomarkers of Cd stress in rice.

STUDY OF THE DELETION MUTATION OF GLUTATHIONE S TRANSFERASE M1 GENE AND ITS ROLE IN SUSCEPTIBILITYTO HEPATOCELLULAR CARCINOMA

Objection: To investigate the glutathione S transferase M1 (GSTM1) gene inherent deletion and its relation to prevalence of hepatocellular carcinoma (HCC) in Guangxi, China. Methods: The GSTM1 gene polymorphism of 120 HCC patients and 100 healthy subjects both from the same high aflatoxin B1 (AFB1) contaminated area were detected using PCR technique with special primers. Another 40 patients from AFB1 low risk area were also tested. Results: In HCC high risk area, it was found that the frequencies of GSTM1 null genotype in HCC patients and healthy subjects were 59% and 51% respectively, with no significant difference. However, the frequency of GSTM1-null genotype in control group from AFB1 low risk area was lower than those from high risk area (P<0.01). Conclusion: Populations in this HCC endemic region show a higher rate of GSTM1-null genotype, which may be partially responsible for the susceptibility to AFB1 induced HCC. But the detoxification effect of GSTM1 alone is not sufficient to resist the genetic toxicity of AFB1, especially in those people who expose to excess AFB1. The GSTM1 gene deletion would not be suitable as an independent predictor of susceptibility to HCC.

Increased oxidative damage of sperm and seminal plasma in men with idiopathic infertility is higher in patients with glutathione S-transferase Mu-1 null genotype

Aim： To examine whether a relationship exists between glutathione S-transferase Mu-1 （GSTM1） gene polymorphism and the susceptibility of sperm and seminal plasma from patients with idiopathic infertility to oxidative stress. Methods： Fifty-two men with idiopathic infertility and 60 healthy fertile men were recruited to this study. GSTM1 gene polymorphism was determined by polymerase chain reaction （PCR） and both the infertile and control individuals were divided into GSTM1 null and GSTM1 positive groups according to their GSTM1 gene structure. We compared reactive oxygen species （ROS） generation, malondialdehyde （MDA）, protein carbonyls and glutathione （GSH） concentrations, and glutathione S-transferase （GST） activity in seminal plasma and spermatozoa from infertile patients and controls with respect to GSTM1 genotype. Results： Significantly higher levels of oxidative stress and damage markers were found in idiopathic infertile men with the GSTM1 null genotype compared with those with the GSTM1 positive genotype. There was no significant difference in genotype distribution for theGSTM1 variant between the idiopathic infertile subjects and fertile subjects. Patients with the GSTM1 null genotype also had lower sperm concentrations than those with GSTM1 positive genotype. Conclusion： Our results suggest that the susceptibility of sperm and seminal plasma to oxidative stress is significantly greater in idiopathic infertile men with the GSTM1 null genotype compared with those possessing the gene. Therefore, in patients with idiopathic infertility, GSTM1 polymorphism might be an important source of variation in susceptibility of spermatozoa to oxidative damage.

Glutathione S-transferase M1 polymorphism and esophagealcancer risk:An updated meta-analysis based on 37 studies

AIM: To evaluate the relationship between glutathione S-transferase M1(GSTM1) polymorphism and susceptibility to esophageal cancer(EC).METHODS: A comprehensive search of the United States National Library of Medicine Pub Med database and the Elsevier, Springer, and China National Knowledge Infrastructure databases for all relevant studies was conducted using combinations of the following terms: "glutathione S-transferase M1", "GSTM1", "polymorphism", and "EC"(until November 1, 2014). The statistical analysis was performed using the SAS software(v.9.1.3; SAS Institute, Cary, NC, United States) and the Review Manager software(v.5.0; Oxford, England); crude odds ratios(ORs) with 95% confidence intervals(CIs) were used to assess the association between the GSTM1 null genotype and the risk of EC.RESULTS: A total of 37 studies involving 2236 EC cases and 3243 controls were included in this metaanalysis. We observed that the GSTM1 null genotype was a significant risk factor for EC in most populations(OR = 1.33, 95%CI: 1.12-1.57, P_(heterogeneity) < 0.000001, and I2 = 77.0%), particularly in the Asian population(OR = 1.53, 95%CI: 1.26-1.86, P_(heterogeneity)< 0.000001, and I2 = 77.0%), but not in the Caucasian population(OR = 1.02, 95%CI: 0.87-1.19, P_(heterogeneity) = 0.97, and I2 = 0%).CONCLUSION: The GSTM1 null polymorphism may be associated with an increased risk for EC in Asian but not Caucasian populations.

Genetic polymorphism of glutathione S-transferase T1 gene and susceptibility to idiopathic azoospermia or oligospermia in northwestern China

Aim： To investigate the association of glutathione S-transferase T1 （GSTT1） gene polymorphism in patients with idiopathic azoospermia or oligospermia in the northwestern China population. Methods： In the case-control study, GSTT1 genotypes were identified by multiplex polymerase chain reaction （PCR） with peripheral blood DNA samples from 78 patients with idiopathic azoospermia, 103 patients with idiopathic oligospermia and 156 age-matched controls with normal sperm concentration and motility, according to the criteria adapted from World Health Organization guidelines. All of the patients and controls were from northwestern China. Results： There is a significant association between GSTT1 null genotype with idiopathic azoospermia risk （odds ratio [OR]： 2.36, 95% confidence interval [CI]： 1.33-4.20, P = 0.003） or idiopathic oligospermia risk （OR： 2.00, 95% CI： 1.17-3.27, P = 0.010）. Conclusion： GSTT1 null genotype is a predisposing risk factor for sporadic idiopathic azoospermia or oligospermia in northwestern China. （Asian J Androl 2008 Mar; 10： 266-270）

Polymorphism of Glutathione S-transferase T1,M1 and P1 Genes in a Shanghai Population: Patients With Occupational or Non-occupational Bladder Cancer

Objective Glutathione S-transferases are involved in the conjugation of xenobiotics. To explore whether GSTs polymorphisms are involved in the development of occupational or non-occupational bladder cancer, polymorphism frequencies of GSTT1, M1 and P1 were investigated in a normal population, which had been settled in a rural area in Shanghai suburb for at least 5 generations as well as in a group of patients with benzidine exposure related occupational bladder cancer in Shanghai dyestuff industry and a group of patients with non-occupational bladder cancer. Methods PCR based procedures were performed in the study populations to confirm the genotypes of GSTT1, M1 and P1. Results The polymorphisms at locus of GSTP1- A1578G in the normal population differed significantly from those in Caucasians or African Americans. All the subjects genotyped so far (n =118) bore only homogenous wild genotype (C2293/ C2293) at GSTP1 - C2293T locus. This locus seemed to be a monomorphic in Shanghai population. No significant difference in GSTT1 and GSTM1 polymorphic form frequencies could be confirmed among three groups of subjects. An overrepresentation of GSTP1 AG or GG genotype corresponding a less stable and less effective isozyme protein was detected in patients with benzidine related occupational bladder cancer, compared with that in the normal population though a statistical significance was not yet reached (P=0.09, OR=1.96, 95% CI 0.89-4.32,). Conclusion This study suggests that GSTM1 or GSTT1 homozygous deficiency genotypes and their combination do not have a clear impact on bladder cancer incidence in a Shanghai population. It seems that GSTP1 polymorphism is not associated with non-occupational bladder cancer. GSTP1 AG or GG genotype has a higher frequency in the patients with benzidine related occupational bladder cancer, and further work is needed to confirm if GSTP1 AG or GG genotype plays a role in the development of occupational bladder cancer.

Polymorphisms of the oxidant enzymes glutathione S-transferase and glutathione reductase and their association with resistance of Plasmodium falciparum isolates to antimalarial drugs

Objective:To investigate the association between amplification of the two regulatory genes controlling glutathione(GSH) levels,glutathione reductase(PfGR) and glutathione S-transferase (PfGST) genes and sensitivity of Plasmodium falciparum(P.falciparum) isolates collected from different malaria endemic areas of Thailand to standard antimalarial drugs.Methods:A total of 70 P.falciparum isolates were collected from endemic areas of multi-drug resistance (Tak,Chantaburi and Ranong Provinces) during the year 2008-2009.The in vitro assessment of antimalarial activity of P.falciparum clones(K1- and Dd2 chloroquine resistant and 3D7- chloroquine sensitive) and isolates to chloroquine,quinine,mefloquine and arteusnate was performed based on SYBR Green modified assay.Results:68(97.14%),11(15.71%) and 28(40%) isolates respectively were classified as chloroquine-,quinine- and mefloquine-resistant isolates. With this limited number of P.falciparum isolates included in the analysis,no significant association between amplification of PfGST gene and sensitivity of the parasite to chloroquine, quinine,mefloquine and quinine was found.Based on PCR analysis,Dd2,Kl and 3D7 clones all contained only one copy of the PfGST gene.All isolates(70) also carried only one copy number of PfGST gene.There appears to be an association between amplification of PfGR gene and chloroquine resistance.The 3D7 and Dd2 clones were found to carry only one PfGR gene copy, whereas the K1 clone carried two gene copies.Conclusions:Chloroquine resistance is likely to be a consequence of multi-factors and enzymes in the GSH system may be partly involved. Larger number of parasite isolates are required to increase power of the hypothesis testing in order to confirm the involvement of both genes as well as other genes implicated in glutathione metabolism in conferring chloroquine resistance.

Theoretical Study on GSH Activation Mechanism of a New Type of Glutathione Transferase Gtt2

Glutathione transferases（GSTs） play an important role in the detoxification of xenobiotic/endobiotic toxic compounds. The α-, π-, and/l-classes of cytosolic GSTs have been studied extensively, while Gtt2 from Saccharo- myces cerevisiae, a novel atypical GST, is still poorly understood. In the present study, we investigated the gluta- thione（GSH） activation mechanism of Gtt2 using the density functional theory（DFT） with the hybrid functional B3LYP. The computational results show that a water molecule could assist a proton transfer between the GSH thiol and the N atom of His133. The energy barrier of proton transfer is 46.0 kJ/mol. The GSH activation mechanism and the characteristics of active site are different from those of classic cytosolic GSTs.

Induction of Glutathione and Glutathione S-transferase in Several Crops with the Treatment of Acetochlor

The response of glutathione(GSH) content and glutathione S-transferease(GST) activity to the acetochlor in roots and shoots of the maize 'Dongnong248',the sorghum 'Aoza No.2' and millet'Yugu' was evaluated.The concentrations of pre-emergence acetochlor causing a 50% inhibition of plant shoot height were 25 μmol·L^(-1) for the tolerant 'Dongnong248' maize,5 μmol·L^(-1) for the sensitive 'Aoza No.2' sorghum and 0.5 μmol·L^(-1) for the very sensitive 'Yugu'millet.Pre-treatment with 10 μmol·L^(-1) of acetochlor induced the root GST activities and nonprotein thiol content of all three cultivars.The induction of root GST activities and nonprotein thiol content compared to controls are observed on the fourth day after acetochlor treatment,The extents of activity and content increase from the higher to the lower were:tolerant maize cultivar 'Dongnong248'>sorghum cultivar'Aoza No.2'>millet cultivar 'Yugu'.The activities and contents induced in shoots were similar to that in roots,but the degrees of increase were less.Under different concentration treatment,the thiol content and GST activities increased with the herbicide concentration rising,then reached their peaks and began to decrease in all tested crop seedlings.The extent of induced GST activities and thiol content correlated well with differential cultivar resistance to acetochlor,so their protective mechanism appears to be strongly dependent on the endogenous levels of GSH and activities of GST.

Molecular evaluation of glutathione S transferase family genes in patients with sporadic colorectal cancer

AIM To evaluate the association between polymorphismsin glutathione S transferases(GSTs) and the risk of sporadic colorectal cancer(SCRC), tumor progression and the survival of patients.METHODS A case-control study of 970 individuals from the Brazilian population was conducted(232 individuals from the case group with colorectal cancer and 738 individuals from the control group without a history of cancer). PCR multiplex and PCR-RFLP techniques were used to genotype the GST polymorphisms. The tumors were categorized according to the TNM classification: tumor extension(T), affected lymph nodes(N), and presence of metastasis(M). Logistic regression, multiple logistic regression and survival analysis were used to analyze the data. The results are presented in terms of odds ratio(OR) and 95% confidence interval(CI). The level of significance was set at 5%(P ≤ 0.05).RESULTS Age equal to or over 62 years(OR = 8.79; 95%CI: 5.90-13.09, P < 0.01) and female gender(OR = 2.91; 95%CI: 1.74-4.37; P < 0.01) were associated with increased risk of SCRC. Analysis of the polymorphisms revealed an association between the GSTM1 polymorphisms and a risk of SCRC(OR = 1.45; 95%CI: 1.06-2.00; P = 0.02), as well as between GSTT1 and a reduced risk of the disease(OR = 0.65; 95%CI: 0.43-0.98; P = 0.04). An interaction between the presence of the wild-type allele of GSTP1 Ile105 Val polymorphism and tobacco consumption on risk of SCRC(OR = 2.33; 95%CI: 1.34-4.05; P = 0.05) was observed. There was an association between the GSTM1 null genotype and the presence of advanced tumors(OR = 2.33; 95%CI: 1.23-4.41; P = 0.009), as well as increased risk of SCRC in the presence of a combination of GSTT1 non-null/GSTM1 null genotypes(OR = 1.50; 95%CI: 1.03-2.19; P = 0.03) and GSTT1 non-null/GSTM1 null/GSTP1 Val~*(OR = 1.85; 95%CI: 1.01-3.36, P = 0.04). Combined GSTT1 non-null/GSTM1 null genotypes(OR = 2.40; 95%CI: 1.19-4.85; P = 0.01) and GSTT1 non-null/GSTM1 null/GSTP1 Val~*(OR = 2.92; 95%CI: 1.05-8.12; P = 0.04) were associated with tumor progression. Polymorphisms were not associated with the survival of patients with SCRC.CONCLUSION Females aged 62 years or older are more susceptible to SCRC. Polymorphisms of GSTT1 and GSTM1 null genotypes modulated the susceptibility to SCRC in the population studied.