Molecular identification and biochemical characteristics of a delta class glutathione S-transferase gene(FcδGST)from Chinese shrimp Fenneropenaeus chinensis

Glutathione S-transferases(GSTs)are a superfamily of multifunction enzymes involved in the regulation of redox homeostasis and innate immune responses against various pathogenic infections in marine invertebrates.In the present study,a delta class GST gene(designated as FcδGST)was cloned from Fenneropenaeus chinensis using rapid amplification of c DNA ends(RACE)technology.The complete cDNA sequence of FcδGST was 780 bp in length,which includes a 27-bp 5′non-coding region(UTR),a 117-bp 3′UTR,a 636-bp open reading frame(ORF),and a polyadenylate signal site(AATAAA)presented at the upstream of poly A tail.The FcδGST gene encoded 211 amino acids peptide,including a GST_N domain and a GST_C domain,and exhibited high similarity with previously reported delta GSTs.The predicted molecular mass of FcδGST protein was 23.39 kDa,and its theoretical isoelectric point(pI)was 5.34.The FcδGST mRNA transcripts were ubiquitously expressed in all the tested tissues,with the highest expression level in hemocytes and hepatopancreas.During the stimulation of Vibrio anguillarum or white spot syndrome virus(WSSV),the m RNA expression of FcδGST in hemocytes and hepatopancreas revealed significant up-regulation.The purified recombinant FcδGST protein(designated as rFcδGST)exhibited specific catalytic activity against 1-chloro-2,4-dinitrobenzene(CDNB)substrate with relatively low stable enzymatic activities.These results indicated that FcδGST was a fragile but typical novel delta class GST member and potentially involved in the innate immune responses of F.chinensis.

Glutathione S-Transferase(GST)Identified from Giant Kelp Macrocystis pyrifera Increases the Copper Tolerance of Synechococcus elongatus PCC 7942

The glutathione S-transferases gene family plays an important regulatory role in growth and development,and responses to environmental change.In this study,six complete GST genes(Mp GST1,Mp GST2,Mp GST3,MpGST4,Mp GST5,and Mp GST6)were cloned from the gametophytes of brown alga Macrocystis pyrifera.Subsequent bioinformatics analysis showed that these six genes encoded proteins with 202,216,288,201,205,and 201 aa,respectively.Moreover,Mp GST3 differs from the other GST genes.Phylogenetic analysis suggested that MpGST3 belongs to the Ure2p type GST.Domain analysis suggested that the other GSTs from M.pyrifera belong to the soluble GST family and form an independent branch with the GSTs found in the other macroalgae,suggesting that a new GST type was formed during macroalgal evolution.GST genes were upregulated in M.pyrifera when 2.5 mg L^(-1)Cu ions were added to the medium.Six GST genes were integrated into the genome of Synechococcus elongatus PCC 7942,and their functions were verified by measuring light absorbance,photosynthetic pigment content,and photosynthetic parameters of the transformed strains under 0.3 mg L^(-1)Cu ion stress.The results showed much higher levels of various parameters in the transformed strains than in the wild strain.The transformed strains(with the MpGST genes)showed significantly enhanced resistance to Cu ion stress,while the wild strain almost died.The results of this study lay a theoretical foundation for further research on the Cu ion stress resistance function of GSTs in M.pyrifera.

芥菜BjGSTF12基因克隆及表达分析

为了探究谷胱甘肽转移酶编码基因(GST)在芥菜花青素积累中的作用,该文以紫薹-绿薹芥菜近等位基因系为材料,克隆到1个花青素积累相关的GST基因,命名为BjGSTF12。该文对BjGSTF12编码蛋白及其启动子进行生物信息学分析,并分析其在绿薹、紫薹芥菜中的表达水平及其与花青素含量的关系。结果表明:(1)BjGSTF12的基因组和cDNA全长分别为808、651 bp,编码216个氨基酸,具有GST_N端和GST_C端保守结构域。然而,绿薹、紫薹芥菜BjGSTF12序列无区别。(2)BjGSTF12与拟南芥AtGSTF12亲缘关系最近,同属于φ亚家族。(3)2个芥菜品系BjGSTF12启动子序列存在4处碱基突变/插入,但二者顺式作用元件种类与数目相同,均含9个MYB结合位点、1个赤霉素响应元件、3个非生物胁迫响应元件。(4)紫薹芥菜花青素含量显著高于绿薹芥菜,BjGSTF12表达水平与花青素含量表现出类似变化规律。(5)互作蛋白网络分析表明,BjGSTF12与花青素合成关键酶、糖基化修饰、转运蛋白等蛋白存在互作。综上认为,BjGSTF12在芥菜薹茎花青素积累中可能发挥重要作用,BjGSTF12可能通过互作蛋白调控芥菜花青素合成、修饰、转运从而影响花青素积累。该文对深入研究GST在芥菜薹茎花青素积累的功能及作用机制奠定了一定理论基础。

Glutathione S-transferase(GST) gene expression profiles in two marine bivalves exposed to BDE-47 and their potential molecular mechanisms

Glutathione S-transferases(GSTs) are phase II enzymes that facilitate the detoxification of xenobiotics and play important roles in antioxidant defense. We investigated the expression patterns of seven Venerupis philippinarum GSTs( Vp GSTs) and four Mytilus galloprovincialis GSTs( Mg GSTs) following exposure to BDE-47. Differential expressions of the seven V p GSTs and four Mg GSTs transcripts were observed,with differences between the hepatopancreas and gills. Among these GSTs,the sigma classes( Vp GSTS1,Vp GSTS2,Vp GSTS3,Mg GST1,and Mg GST3) were highly expressed in response to BDE-47 exposure,demonstrating their potential as molecular biomarkers for environmental biomonitoring studies. We obtained the three-dimensional crystal structures of V p GSTs and Mg GSTs by homologous modeling. A model to elucidate the binding interactions between the ligands and receptors was defined by molecular docking. Hydrophobic and π were the most often observed interactions between BDE-47 and the GSTs.

Transcriptome-based identification and expression analysis of the glutathione S-transferase(GST)family in tree peony reveals a likely role in anthocyanin transport

For red-flowered cultivars of tree peony(Paeonia suffruticosa),anthocyanin content is a critical factor determining the different petal pigmentations.Glutathione S-transferases(GSTs)are ubiquitous and multifunctional conjugating proteins that may be responsible for the transport of anthocyanin pigments from the cytoplasm to vacuole.The underlying function of the GST family in tree peony,however,remains unclear.In this study,we systematically isolated and identified a total of 54 putative full-length Ps GST genes through a combination of bioinformatics approaches from transcriptome databases.Intraspecific phylogenetic analyses revealed extensive differentiation in their coding sequences and divided them into 10 of the 14 known classes of plant GSTs.The phylogenetic relationships,evolutionary characteristics,protein domain,and motif organization were clearly conserved among the different phylogenetic subclasses.The results of the RNA-seq and quantitative real-time polymerase chain reaction experiments exhibited extensive variation in gene expression profiles among different developmental stages and varieties.Furthermore,the phylogenetic relationships,expression profiles,protein interactions,weighted gene co-expression network analysis,and correlation analysis results suggested that PsGSTF3(Unigene 0064200)is a candidate participant in anthocyanin transport and the promotion of pigment accumulation,exhibiting a strong positive correlation with anthocyanin content among different tissues(r=0.908**)and an increasing rate of anthocyanin content during the flower developmental process(r=0.961*).These results furthered our understanding of the transport and accumulation functions of the GST family as well as the enhancement of tree peony breeding through molecular biology techniques.

GST family genes in jujube actively respond to phytoplasma infection

Jujube witches’broom(JWB)caused by phytoplasma has a severely negative effect on multiple metabolisms in jujube.The GST gene family in plants participates in the regulation of a variety of biotic and abiotic stresses.This study aims to identify and reveal the changes in the jujube GST gene family in response to phytoplasma infection.Here,70 ZjGSTs were identified in the jujube genome and divided into 8 classes.Among them,the Tau-class,including 44 genes,was the largest.Phylogenetic analysis indicated that Tau-class genes were highly conserved among species,such as Arabidopsis,cotton,chickpea,and rice.Through chromosome location analysis,37.1%of genes were clustered,and 8 of 9 gene clusters were composed of Tau class members.Through RT-PCR,qRT-PCR and enzyme activity detection,the results showed that the expression of half(20/40)of the tested ZjGSTs was inhibited by phytoplasma infection in field and tissue culture conditions,and GST activity was also significantly reduced.In the resistant and susceptible varieties under phytoplasma infection,ZjGSTU49-ZjGSTU54 in the cluster IV showed opposite expression patterns,which may be due to functional divergence during evolution.Some upregulated genes(ZjGSTU45,ZjGSTU49,ZjGSTU59,and ZjGSTU70)might be involved in the process of jujube against JWB.The yeast two-hybrid results showed that all 6 Tauclass proteins tested could form homodimers or heterodimers.Overall,the comprehensive analysis of the jujube GST gene family revealed that ZjGSTs responded actively to phytoplasma infection.Furthermore,some screened genes(ZjGSTU24,ZjGSTU49-52,ZjGSTU70,and ZjDHAR10)will contribute to further functional studies of jujube-phytoplasma interactions.

冷胁迫下甘蓝型冬油菜表达蛋白及BnGSTs基因家族的鉴定与分析

谷胱甘肽S-转移酶(glutathione S-transferases, GST)参与调节植物生长、发育和逆境胁迫反应的许多方面。本研究利用双向电泳和质谱技术分析‘16VHNTS309’在冷胁迫下差异表达的蛋白质,基于GO和KEGG分析鉴定出BE、APX、SOD、GST等参与冷胁迫反应的蛋白质。利用q RT-PCR和生理指标鉴定到响应冷胁迫的关键蛋白质GST,采用同源克隆法克隆到‘16VHNTS309’的GST基因。该基因CDS长度为642bp,编码213个氨基酸,是一个不稳定蛋白,属于GST_N_3谷胱甘肽S-转移酶家族,与甘蓝型油菜‘ZS11’序列相似性为99.22%,与‘ZS11’和‘Vision’两者的氨基酸序列相比较发现第127位亮氨酸(L)突变为脯氨酸(P)。基因家族分析表明,在甘蓝型油菜中共鉴定到153个Bn GSTs成员,按其功能主要分为Zeta、Phi、Theta、CHQ、DHAR、Lambda和Tau这七大类型,大部分的Bn GSTs属于Phi和Tau这2种类型。系统进化将Bn GSTs分为12个亚家族,亚家族Ⅰ和Ⅷ包含了较多的成员,Bn GSTs不均匀的分布在18条染色体上, C06染色体上分布Bn GSTs基因数量最多,含有10个保守的蛋白质基序。Bn GSTs基因家族中有99对基因存在共线性关系, 131个基因来自基因复制事件,片段重复事件在Bn GSTs基因的进化中起着重要作用。冷胁迫下Bna A02g35760D、Bna C06g20450D、Bna C06g35490D、Bna A02g03230D和Bna A02g35980D在强抗寒品种中的显著高表达,是弱抗寒品种的7~12倍,并且强抗寒品种具有较高的生理酶活性。另外,在冷冻胁迫下鉴定到一些瞬时和持续表达的关键候选基因。这些结果为进一步研究Bn GSTs基因在强抗寒甘蓝型冬油菜抗寒分子调控中的作用奠定基础。

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.

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.

食管胃交界部腺癌肿瘤浸润淋巴细胞中FoxM1、GST-π表达情况与分化程度、转移及预后的关系

目的 分析食管胃交界部腺癌(AEGJ)肿瘤浸润淋巴细胞(TILs)中叉头框蛋白M1(FoxM1)、谷胱甘肽-S-转移酶-Pi(GST-π)表达情况,探讨其与肿瘤分化程度、转移及患者预后之间的关系。方法 将60例行手术治疗的AEGJ患者纳为研究对象,术中留取癌灶组织与癌旁组织,机械法分离出癌灶组织及癌旁组织内TILs,流式技术检测TILs中FoxM1、GST-π表达量(以含有FoxM1、GST-π抗原细胞的百分率表示)。分析AEGJ癌灶组织及癌旁组织TILs中FoxM1、GST-π表达量与肿瘤临床特征之间的关系。随访3年,比较癌灶组织内TILs中FoxM1、GST-π不同表达量患者生存情况。结果 癌灶组织TILs内FoxM1、GST-π表达水平均高于癌旁组织TILs,差异具有统计学意义(P<0.05)。癌灶组织TILs内FoxM1表达水平与肿瘤TNM分期、浸润深度及淋巴转移相关(P<0.05),TILs内GST-π表达水平与肿瘤分化程度及浸润深度有关(P<0.05)。随访发现,FoxM1高表达组患者3年生存率及中位生存时间均低于低表达组(Rank=4.039,P=0.044),GST-π高表达组患者3年生存率及中位生存时间均低于低表达组(Rank=10.041,P=0.002)。结论 AEGJ组织TILs内FoxM1及GST-π表达水平明显高于癌旁TILs,且与AEGJ病理特点存在一定的关系。FoxM1及GST-π表达水平与AEGJ患者术后生存情况相关,是预测患者预后的潜在指标。

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.

Cloning, characterization and expression analysis of a microsomal glutathione S-transferase gene from the seagrass Zostera marina

The response of glutathione S-transferase(GST)in Zostera marina to temperature variation was analyzed at molecular level by cloning the microsomal GST gene and texting the microsomal GST expression regularity under different temperature.Specific speaking,express ZmGST in Escherichia coli,then purify the recombinant protein and make the thermal stability analysis.Therefore,the experiments were carried out to provide a theoretical basis for the further elaboration to the population degradation mechanisms of Z.marina.In conclusion,the thermostability and the response of ZmGST gene to temperature changes can determine its temperature tolerance range,and affect its resilience in turn.

Characterization of the Purified Glutathione S-transferases from Two Psocids Liposcelis bostrychophila and L.entomophila

Glutathione S-transferases（GSTs） from Liposcelis bostrychophila Badonnel and L.entomophila（Enderlein）（Psocoptera：Liposcelididae） were purified by glutathione-agarose affinity chromatography,and characterized subsequently by their Michaelis-Menten kinetics toward the artificial substrates 1-chloro-2,4-dinitrobenzene（CDNB） and reduced glutathione（GSH）,respectively.The specific activity of the purified GST toward CDNB was 2.3-fold higher in L.bostrychophila than in L.entomophila.Though the specific activities of purified enzymes varied between the two species,the purification yields were similar.SDS-PAGE revealed one band at 23 kDa for both the species.GSTs of L.entomophila exhibited higher Michaelis-Menten constants（Km） but lower maximal velocity（Vmax） values than those of L.bostrychophila.The optimum pH for CDNB conjugation of L.bostrychophila and L.entomophila GSTs was 7.0 and 7.5,and optimum temperature was 35 and 40°C,respectively.Inhibition kinetics showed that cibacron blue,curcumin,bromosulfalein,ethacrynic acid,and carbosulfan had excellent inhibitory effects on GSTs in both species,but the inhibitory effects of beta-cypermethrin,fenpropathrin,tetraethylthiuram disulfide,and diethyl maleate were not significant.

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.

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.

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）

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.

Antioxidant Effect of Selenium-containing Glutathione S-Transferase in Rat Cardiomyocytes

As one of the most important antioxidant enzymes, glutathione peroxidase（GPX） protects cells and tissues from oxidative damage, and plays an important role in cardiovascular and cerebrovascular injuries induced by oxida- tive stress. The antioxidant effect of selenium-containing glutathione S-transferase（Se-GST）, a mimic of GPX was investigated on rat cardiomyocytes. To explore the protection function of Se-GST in hydrogen peroxide（H202） chal- lenged rat cardiomyocytes, we examined malondialdehyde（MDA）, lactate dehydrogenase（LDH）, superoxide dismu- tase（SOD） and cell apoptosis. The results demonstrate exposure of rat cardiomyocytes to H202 for 6 and 12 h induced the significant increases of MDA, LDH and apoptosis rate of cardiomyocytes, but pretreatment of rat cardiomyocytes with Se-GST at 0.0005 or 0.001 unit/mL prevents oxidative stress induced by H202 with the decreases of cell apopto- sis. All the results hint Se-GST has antioxidant activity for oxidative stress challenged rat cardiomyocvtes.

Alteration of glutathione S-transferase properties during the development of Micromelalopha troglodyta larvae (Lepidoptera: Notodontidae)

Micromelalopha troglodyta （Graeser） is an important pest of poplar in China. Glutathione S-transferases （GSTs） are known to be responsible for adaptation mechanisms of M. troglodyta. The activities and kinetic constants of glutathione S-transferases in M. troglodyta were studied. Significant differences in glutathione S-transferase activity and kinetic characteristics were observed among five instars of M. troglodyta larvae. Furthermore, the inhibition of glutathione S-transferase activity in five instars by 24 inhibitors was conducted. The results show the inhibition of GST activity of different instars by 24 inhibitors was different. For GST activity in the 1st instar, chlorpyrifos, lambda-cyhalothrin, endosulfan, abamectin, fipronil and pyridaben were the best inhibitors tested, and for GST activity in the 2nd instar, tannic acid and quercetin were the most potent inhibitors tested, and for GST activity in the 3rd instar, the inhibitory effects of quercetin, chlorpyrifos and lambda-cyhalothrin were the highest, and for GST activity in the 4th instar, quercetin and lambda-cyhalothrin were the best inhibitors, and the inhibitory effect of phoxim was the highest for GST activity in the 5th instar. Our results show that glutathione S-transferases in different instars are qualitatively different in isozyme composition and thus different in sensitivity to inhibitors.