Carboxylesterase and Glutathione-S-Transferase （GST＇s） Induced Resistance to Bacillus thuringiensis Toxin CrylAb in Rice Leaf Folder, Cnaphalocrocis medinalis （Guenee） Populations

The rice leaf folder （RLF）, Cnaphalocrocis medinalis （Guenee） （lnsecta： Lepidoptera： Pyralidae）, is an important pest, widely distributed in many rice growing areas of Asia. The over-use of broad-spectrum chemical insecticides has been cited as a major cause of outbreaks of C. medinalis as excessive spraying of insecticide disrupts natural biological control insecticides still remain the major control tactics against leaf folder. Carbofuran and fenthion, bendiocarb, acephate, carbosulfan, quinolphos, monocrotophos, phosphamidon and fenvalerate are the common ones used against rice leaf folder. Genetically, modified rice lines expressing B. thuringiensis insecticidal crystal proteins produced are highly tolerant to leidopteran pests. Though economic and environmental benefits of GM crops is well established, the matter of concern is the possibility of target insect pest developing resistance to this B. thuringiensis insecticidal toxins, evident from many laboratory and field experiments against many insect pests. The involvement of GSH S-transferase, carboxylesterase, and microsomal monooxygenase in insecticide resistance has been reported in insecticide-resistant strains of many insect species. Hence, the present study was taken up to monitor for cross resistance between B. thuringiensis cry toxins and synthetic insecticides in larvae of leaf folder as it is mediated by carboxylesterase titre and other enzymes by bioassay for two selected rice leaf folder field populations at the Entomology division of Directorate of Rice Research which showed 2-fold resistance ratio. Qualitative and quantitative changes of carboxylesterase （CarE） and glutathione-s-transferase （GST＇s） were worked out with midguts extracts of the two C. medinalis populations in the presence of a-napthyl acetate and chlorodi-nitro benzene substrates.

Modification of the Genetic Polymorphism of Glutathione-S-Transferase (GSTM1 and GSTT1) in Motorcycle Drivers Exposed to BTEX in Cotonou

The glutathione-S-transferase genes mainly the GSTM1 and GSTT1 alleles are responsible for the synthesis of detoxication enzymes that can remove toxic substances. The objective of this study is to seek changes in the genetic polymorphism of glutathione-S-transferase GSTM1 and GSTT1 in motorcycle drivers exposed to BTEX. Our study group consists of 60 motorcycle drivers including 30 professional and 30 non-professional. Blood samples were preleveled from the study population in the EDTA tubes and DNA was extracted by the phenol/chloroform method. The PCR technique was used to determine the presence or absence of genes. Our results showed that the percentage of GSTM1 null genotype has a statistically significant difference (P = 0.02), while the percentage of GSTT1 null genotype was non-significant (P = 0.76) between the two groups. The percentage of deletion of both genes is higher in professional than non-professional motorcycle drivers. Air pollution in Cotonou by BTEX seems to influence the deletion of the GSTM1 and GSTT1 genes at a higher percentage among professional than non-professional motorcycle drivers.

Pharmacogenetics of azathioprine in inflammatory bowel disease: A role for glutathione-S-transferase?

Azathioprine is a purine antimetabolite drug commonly used to treat inflammatory bowel disease (IBD). In vivo it is active after reaction with reduced glutathione (GSH) and conversion to mercaptopurine. Although this reaction may occur spontaneously, the presence of isoforms M and A of the enzyme glutathione-S-transferase (GST) may increase its speed. Indeed, in pediatric patients with IBD, deletion of GST-M1, which determines reduced enzymatic activity, was recently associated with reduced sensitivity to azathioprine and reduced production of azathioprine active metabolites. In addition to increase the activation of azathioprine to mercaptopurine, GSTs may contribute to azathioprine effects even by modulating GSH consumption, oxidative stress and apoptosis. Therefore, genetic polymorphisms in genes for GSTs may be useful to predict response to azathioprine even if more in vitro and clinical validation studies are needed.

Glutathione-S-transferase M1 polymorphisms on the susceptibility to esophageal cancer among three Chinese minorities:Kazakh,Tajik and Uygur

AIM： To investigate the glutathione-S-transferase M1 （GSTM1） polymorphisms in three Chinese minorities, Kazakh, Uygur, and Tajik; and the pathological significance of GSTM1 polymorphisms in esophageal carcinogenesis in Kazakh.METHODS： A total of 1121 blood samples （442 males and 679 females） were obtained from healthy Kazakh （654）, Uygur （412） and Tajik （55）. Primary esophageal squamous cell cancer （ESCC） tissues from Kazakh were obtained from 116 patients who underwent surgery. GSTM1 polymorphisms were analyzed by a combined approach of PCR and electrophoresis techniques.RESULTS： GSTM1 null genotype was found in 62.63% Uygur, 50.91% Tajik and 47.40% Kazakh. A significantly higher frequency of GSTM1 null genotype in Uygur was observed compared with Kazakh （OR： 1.859, 95% CI： 1.445 -2.391, χ^2 = 23.71, P = 0.000）. In addition, GSTM1 null genotype was found in 23.53% of welldifferentiated ESCC in Kazakh, in 49.23% of poorly differentiated ESCC, with a significant difference （OR： 3.152, 95% CI： 1.403-7.080, χ^2 = 8.018, P = 0.007）.CONCLUSION： There is a marked difference in the frequency of common GSTM1 null genotype between Uygur and Kazakh. GSTM1 null genotype is associated with differentiation of ESCC in Kazakh.

Glutathione-S-transferases genes-promising predictors of hepatic dysfunction

diseases pathogenesis are genes that encodes the synthesis of glutathione-Stransferase(GST),known as the second phase enzyme detoxification system that protects against endogenous oxidative stress and exogenous toxins,through catalisation of glutathione sulfuric groups conjugation and decontamination of lipid and deoxyribonucleic acid oxidation products.The group of GST enzymes consists of cytosolic,mitochondrial and microsomal fractions.Recently,eight classes of soluble cytoplasmic isoforms of GST enzymes are widely known:α-,ζ-,θ-,κ-,μ-,π-,σ-,andω-.The GSTs gene family in the Human Gene Nomenclature Committee,online database recorded over 20 functional genes.The level of GSTs expression is considered to be a crucial factor in determining the sensitivity of cells to a broad spectrum of toxins.Nevertheless,human GSTs genes have multiple and frequent polymorphisms that include the complete absence of the GSTM1 or the GSTT1 gene.Current review supports the position that genetic polymorphism of GST genes is involved in the pathogenesis of various liver diseases,particularly non-alcoholic fatty liver disease,hepatitis and liver cirrhosis of different etiology and hepatocellular carcinoma.Certain GST allelic variants were proven to be associated with susceptibility to hepatological pathology,and correlations with the natural course of the diseases were subsequently postulated.

β-catenin accumulation in nuclei of hepatocellular carcinoma cells up-regulates glutathione-s-transferase M3 mRNA

AIM: To identify the differentially over-expressed genes associated with β-catenin accumulation in nuclei of hepatocellular carcinoma (HCC) cells. METHODS: Differentially expressed genes were identified in radiation-induced B6C3 F1 mouse HCC cells by mRNA differential display, Northern blot and RT-PCR, respectively. Total glutathione-s-transferase (GST) activity was measured by GST activity assay and β-catenin localization was detected with immunostaining in radiation-induced mouse HCC cells and in HepG2 cell lines.RESULTS: Two up-regulated genes, glutamine synthetase and glutathione-s-transferase M3 (GSTM3), were identified in radiation-induced mouse HCC cells. Influence of β-catenin accumulation in nuclei of HCC cells on upregulation of GSTM3 mRNA was investigated. The nearby upstream domain of GSTM3 contained the β-catenin/TcfLef consensus binding site sequences [5'-(A/T)(A/T) CAAAG-3'], and the total GST activity ratio was considerably higher in B6C3F1 mouse HCC cells with β-catenin accumulation in nuclei of HCC cells than in those without β-catenin accumulation (0.353 ± 0.117vs 0.071 ± 0.064, P < 0.001). The TWS119 (a distinct GSK-3β inhibitor)-induced total GST activity was significantly higher in HepG2 cells with β-catenin accumulation than in those without β-catenin accumulation in nuclei of HCC cells. Additionally, the GSTM3 mRNA level was significantly higher at 24 h than at 12 h in TWS119-treated HepG2 cells. CONCLUSION: β-catenin accumulation increases GST activity in nuclei of HCC cells, and GSTM3 may be a novel target gene of the β-catenin/Tcf-Lef complex.

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。

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.

Evaluation of Glutathione-S-transferase and ceruloplasmin levels in gingival crevicular fluid and gingival tissue as diagnostic markers for chronic periodontitis

Periodontitis, is an infectious ailment of multifactorial origin, that brings about destruction of bone and surrounding tissues. There are various oral pathogens that may be responsible for the destruction. The host encounters these microbial invasions and their products by the production and release of inflammatory mediators from the cells within the body. Glutathione-S-transferase (GST) are a group of enzymes that utilize glutathione in conditions resulting in oxidative stress. These enzymes play a key role in the detoxifycation of such substance. It aids in preventing damage to important cellular components caused by release of free reactive oxygen species. Ceruloplasmin is a ferroxidase enzyme. It plays a role as an anti-inflammatory agent, by its ability to scavenge free radicals within the body. The present study was targeted at evaluating the levels of Glutathione-S-Transferase (GST) and Ceruloplasmin as diagnostic markers for patients with chronic periodontitis in gingival crevicular fluid (GCF) and the gingival tissues. Thirty patients were divided into two groups. Experimental group comprising of 15 subjects with chronic perio- dontitis and the control group was composed of 15 healthy individuals. Highly significant changes in GST between the diseased and normal patients (P = 0.001) were detected. There was a decrease in GST level in both gingival tissue & GCF in diseased patients when compared to the control patients. The ceruloplasmin levels in GCF and gingival tissues showed no difference between the control and diseased group. Hence,these results indicate a relationship suggesting that GST produced during chronic inflammation could be used as biomarker that indicate periodontal disease .

Immunoprophylactic potential of filarial glutathione-s-transferase in lymphatic filariaisis

Objective:To elucidates the immunoprophylactic potential of glutathion-s-transferase(GST) from cattle filarial parasite Setaria digitata(S.digitata) against lymphatic filariasis.Methods: GST was purified through affinity chromatography(SdGST) and chacterized by SDS-PAGE and Nano-LC MS/MS analysis.Antibody isotypes to SdGST were measured by ELISA.Antibody dependant cellular cytotoxicity(ADCC) was performed in vitro using sera from immunized animals and immune individuals.T-cell proliferation and cytokine response to SdGST in different groups of filariasis were measured.Immunoprophylactic potential of SdGST was evaluate in animal model.Results:SdGST exhibited 30-fold enhancement of enzyme activity over crude parasitic extract.It was found to be 26 kDa by SDS-PAGE.Nano LC-MS/MS analysis followed by blast search showed 100%homology with Dirqfilaria immitis(D.immitis) and only 43%with Homo sapiens(H.sapiens).Immunoblotting analysis showed putatively immune individuals carry significant level of antibodies to SdGST as compared with microfilaraemics.Immunized sera and sera endemic normal could neutralize the enzymatic activity of SdGST and inducing in vitro cytotoxicity of microfilariae.Peripheral blood mononuclear cells(PBMC) from endemic normals upon stimulation with SdGST showed a mixed type of Th1/Th2 response.SdGST immunization clear microfilariae from circulation in S.digitata implanted mastomys.Conclusions:The heterologous GST could be potentially developed as a vaccine candidate against lymphatic filarial parasite.

藜麦GST基因家族鉴定及冷胁迫下表达模式分析

冷胁迫会直接影响植物的生长和发育,并在植物体内不断累积有害物质。谷胱甘肽S-转移酶(glutathione S-transferase, GST)是一种对细胞保护至关重要的抗氧化酶,通过减少活性氧引起的生理性损伤,在生物和非生物应激反应中发挥重要作用。藜麦(Chenopodium quinoa Willd.)中富含蛋白质、氨基酸等对人体有益的物质,但藜麦苗期易受冷空气侵袭而导致减产。因此,鉴定藜麦耐寒相关基因是必要的,为此鉴定藜麦GST基因家族成员,并分析藜麦GST基因在冷胁迫下不同组织中的表达模式。结果表明,在藜麦基因组中共鉴定出59个藜麦GST基因成员,其氨基酸长度范围为199~416 aa,分子量在22.72~47.45 ku范围内,随机分布在14条染色体上,通过系统发育分析将其分为8个亚家族,在启动子区域中分析发现多个低温顺式作用元件(LTR)和多种生长发育及代谢相关的元件。在藜麦GST基因家族中共发现11对串联重复基因和11对片段重复基因,表明基因复制事件是该物种GST基因家族进化的主要驱动力。基因的组织特异性表达分析结果显示,大多数藜麦GST基因在不同持续时间的冷胁迫下可以作出响应,特别是在叶片上高表达。结果可为进一步研究藜麦GST基因功能提供基础,为藜麦耐寒品种选育提供候选基因。

Systematic analysis and functional verification of citrus glutathione S-transferases reveals that CsGSTF1 and CsGSTU18contribute negatively to citrus bacterial canker

Citrus bacterial canker(CBC) is resulted from Xanthomonas citri subsp. citri(Xcc) infection and poses a significant threat to citrus production.Glutathione S-transferases(GSTs) are critical in maintaining redox homeostasis in plants, especially in relation to abiotic and biotic stress responses. However, the function of GSTs in resisting CBC remains unclear. Here, citrus glutathione S-transferases were investigated applying a genome-wide approach. In total, 69 CsGSTs belonging to seven classes were identified, and the phylogeny, chromosomal distribution, gene structures and conserved motifs were analyzed. Several CsGSTs responded to Xcc infection, as observed in the upregulation of CsGSTF1 and CsGSTU18 in the CBC-sensitive ‘Wanjincheng' variety but not in the resistant ‘Kumquat' variety. CsGSTF1 and CsGSTU18 were localized at the cytoplasm. Transient overexpression of CsGSTF1 and CsGSTU18 mediated reactive oxygen species(ROS) scavenging, whereas the virus-induced gene silencing(VIGS) of CsGSTF1 and CsGSTU18 caused strong CBC resistance and ROS burst. The present study investigated the characterization of citrus GST gene family, and discovered that CsGSTF1 and CsGSTU18 negatively contributed to CBC through modulating ROS homeostasis. These findings emphasize the significance of GSTs in infection resistance in plants.

Genetic polymorphism of glutathione-S-transferase M1 and T1 in associated with carcinogenesis of hepatocellular carcinoma and nasopharyngeal carcinoma

Objective:The aim of our study was to investigate the distribution of glutathione-S-transferase M1 (GSTM1) and T1 (GSTT1) gene polymorphism in hepatocellular carcinoma (HCC) and nasopharyngeal carcinoma (NPC) patients in a high risk area in Guangxi Zhuang Autonomous Region,China.Methods:It was a case-control study.The genotypes of GSTM1 and GSTT1 in 181 HCC and 126 NPC patients were compared with 641 matched control.The GSTM1 and GSTT1 genotypes were detected using conventional multiplex PCR method.Results:The frequency of GSTM1 null genotype in HCC,NPC and control groups were 65.2%,61.9% and 47.6% respectively,significant difference between these two cancer groups and control was observed (P < 0.01).The frequency of GSTT1 null genotype in HCC,NPC and control groups were 57.5%,62.7% and 43.1% respectively,significant difference between these two cancer groups and control was observed (P < 0.01).Conclusion:The distributions of GSTM1 and T1 genes are polymorphic in HCC and NPC patients in a high risk area in Guangxi,individuals with GSTM1-null or GSTT1-null would have an increasing risk of developing HCC and NPC,especially when combination with virus infection (HBV or EBV) and absorbed chemical toxin (AFB1 or cigarette).

Plasma catalase,glutathione-s-transferase and total antioxidant activity levels of children with attention deficit and hyperactivity disorder

Objective: In this study, we plan to measure plasma Catalase (CAT), Antioxidant Activity (AOA) and Glu- tathione-S-Transferase (GST) levels to understand whether oxidative stress develops or not and whether or not the detoxification mechanism properly functions in children with Attention Deficit and Hyperactivity Disorder (ADHD) with unknown etiology and pathogenesis. Method and Results: Plasma CAT, AOA, and GST activities were spectrophotometrically measured in forty patients (average age 10.27 ± 2.54) and thirty-five (average age, 9.97 ± 2.59) healthy individuals as the control group. While the CAT activity showed no difference in the patient group (P > 0.05) compared to the control group, AOA and GST levels were found significantly meaningful (P = 0.001). Conclusion: In this pilot study ,the study shows that no oxidative stress develops in individuals with ADHD in high AOA and stable CAT activity, and that the de- toxification mechanism functions extremely in high GST activity. These findings need to be supported by other studies.

Rapid discovery of a novel “green” and natural GST inhibitor for sensitizing hepatocellular carcinoma to Cisplatin by visual screening strategy

Over-expression of glutathione S-transferase(GST)can promote Cisplatin resistance in hepatocellular carcinoma(HCC)treatment.Hence,inhibiting GST is an attractive strategy to improve Cisplatin sensitivity in HCC therapy.Although several synthesized GST inhibitors have been developed,the side effects and narrow spectrum for anticancer seriously limit their clinical application.Considering the abundance of natural compounds with anticancer activity,this study developed a rapid fluorescence technique to screen“green”natural GST inhibitors with high specificity.The fluorescence assay demonstrated that schisanlactone B(hereafter abbreviated as C1)isolated from Xue tong significantly down-regulated GST levels in Cisplatin-resistant HCC cells in vitro and in vivo.Importantly,C1 can selectively kill HCC cells from normal liver cells,effectively improving the therapeutic effect of Cisplatin on HCC mice by downregulating GST expression.Considering the high GST levels in HCC patients,this compound demonstrated the high potential for sensitizing HCC therapy in clinical practice by down-regulating GST levels.

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.

Genome-Wide Identification of the GST Gene Family in Loquat (Eriobotrya japonica Lindl.) and Their Expression under Cold Stress with ALA Pretreatment

Loquat(Eriobotrya japonica Lindl.),a rare fruit native to China,has a long history of cultivation in China.Low temperature is the key factor restricting loquat growth and severely affects yield.Low temperature induces the regeneration and metabolism of reduced glutathione(GSH)to alleviate stress damage via the participation of glu-tathione S-transferases(GSTs)in plants.In this study,16 GSTs were identified from the loquat genome according to their protein sequence similarity with Arabidopsis GSTs.On the basis of domain characteristics and phyloge-netic analysis of AtGSTs,these EjGSTs can be divided into 4 subclasses:Phi,Theta,Tau and Zeta.The basic prop-erties,subcellular localization,structures,motifs,chromosomal distribution and collinearity of the EjGST proteins or genes were further analyzed.Tandem and segmental gene duplications play pivotal roles in EjGST expansion.Cis-elements that respond to various hormones and stresses,especially those associated with low-temperature responsiveness,were predicted to be present in the promoters of EjGSTs.Moreover,analysis of gene expression profiles revealed that 9 of 16 EjGSTs may be involved in the low-temperature responsiveness of loquat leaves.In agriculture,5-aminolevulinic acid(ALA),a potential multifunctional plant growth regulator,can improve the stress response of plants.Among the 9 low-temperature-responsive EjGSTs,the expression of EjGSTU1 and EjGSTF1 significantly differed under cold stress in response to exogenous 5-aminolevulinic acid(ALA)pretreat-ment.The remarkable increase in GST activity and GSH/GSSG ratio reflected the increase in the cold response ability of loquat plants caused by exogenous ALA,thereby alleviating H2O2 accumulation and membrane lipid preoxidation.Overall,this study provides an initial exploration of the cold tolerance function of GSTs in loquat,offering a theoretical foundation for the development of cold-resistant loquat cultivars and new antifreeze agents.

壬基酚对牙鲆肝脏EROD和GST酶活性的影响

乙氧基-异酚恶唑脱乙基酶(EROD)和谷胱甘肽转移酶(GST)是动物体内主要的解毒酶,在外源毒物的转化和代谢过程中具有重要作用。本文应用牙鲆肝脏组织中的EROD和GST酶活性作为生物标志物,研究了不同浓度的壬基酚(0,0.10,0.33和1.00 mg·L^(-1))活体暴露下2种酶的活性响应特征。结果表明,与对照组相比,暴露于低浓度(0.10和0.33 mg·L^(-1))的壬基酚中,EROD和GST酶活性均被诱导,暴露4 d后0.33 mg·L^(-1)的壬基酚处理组中EROD和GST活性的诱导率分别为99.2%和127.5%。暴露于高浓度(1.00 mg·L^(-1))的王基酚中。2种酶的活性均被抑制,4 d后EROD和GST酶活性的抑制率分别为62.0%和37.3%。该试验表明,EROD和GST酶活性的响应可用来评价环境中壬基酚的污染效应。

镉胁迫下两种水稻GSH和GST应答差异的研究

还原型谷胱甘肽(GSH)和谷胱甘肽转硫酶(GST)是水稻解毒系统中的重要组成部分。采用水培法研究了耐性不同的两种水稻(特优559和K优818)在不同程度镉(Cd)胁迫下GSH和GST的变化情况。结果表明,Cd处理导致两种水稻生物量减少、Cd吸收积累增加,水稻根部Cd含量和积累量均高于地上部,但Cd从水稻根部向地上部的转运存在明显的种间差异,耐性较弱的特优559的Cd转移率(S/R)随处理Cd浓度提高而上升,而耐性较强的K优818则恰好相反,将Cd更多地钝化在根部。两种水稻GSH和GST的变化趋势也有所不同,Cd胁迫使特优559的GSH含量和GST活性显著增加,而K优818的GSH在低浓度Cd处理时出现了小幅下降,但其GST活性变化与特优559相似,根部增幅更为显著。以上结果说明,水稻GSH和GST在Cd解毒和钝化过程中发挥了重要的作用,而且其应答机制存在着一定的基因型差异,这可能与两品种GST同功酶的组成、表达和功能不同有关。

GST-NAP融合蛋白可溶性表达及柱上切割GST标签

利用基因工程的方法,以实验室保存的p MAL-C2X-NAP质粒为模板,PCR扩增NAP基因,构建重组质粒p GEX-NAP.重组质粒通过酶切和测序鉴定后转化大肠杆菌表达菌株BL21(DE3),再经IPTG低温诱导获得可溶性GST-NAP融合蛋白,最后利用谷胱甘肽琼脂糖凝胶树脂进行纯化,Prescission蛋白酶进行柱上切割去除GST标签.结果表明,p GEX-NAP重组质粒构建正确,在大肠杆菌中经IPTG低温诱导表达,可获得大量可溶性GST-NAP融合蛋白.Prescission蛋白酶柱上切割去除GST标签后,经Western Blot验证NAP蛋白能被兔抗NAP多克隆抗体特异识别.