Silent information regulator sirtuin 1 ameliorates acute liver failure via the p53/glutathione peroxidase 4/gasdermin D axis

BACKGROUND Acute liver failure(ALF)has a high mortality with widespread hepatocyte death involving ferroptosis and pyroptosis.The silent information regulator sirtuin 1(SIRT1)-mediated deacetylation affects multiple biological processes,including cellular senescence,apoptosis,sugar and lipid metabolism,oxidative stress,and inflammation.AIM To investigate the association between ferroptosis and pyroptosis and the upstream regulatory mechanisms.METHODS This study included 30 patients with ALF and 30 healthy individuals who underwent serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)testing.C57BL/6 mice were also intraperitoneally pretreated with SIRT1,p53,or glutathione peroxidase 4(GPX4)inducers and inhibitors and injected with lipopolysaccharide(LPS)/D-galactosamine(D-GalN)to induce ALF.Gasdermin D(GSDMD)^(-/-)mice were used as an experimental group.Histological changes in liver tissue were monitored by hematoxylin and eosin staining.ALT,AST,glutathione,reactive oxygen species,and iron levels were measured using commercial kits.Ferroptosis-and pyroptosis-related protein and mRNA expression was detected by western blot and quantitative real-time polymerase chain reaction.SIRT1,p53,and GSDMD were assessed by immunofluorescence analysis.RESULTS Serum AST and ALT levels were elevated in patients with ALF.SIRT1,solute carrier family 7a member 11(SLC7A11),and GPX4 protein expression was decreased and acetylated p5,p53,GSDMD,and acyl-CoA synthetase long-chain family member 4(ACSL4)protein levels were elevated in human ALF liver tissue.In the p53 and ferroptosis inhibitor-treated and GSDMD^(-/-)groups,serum interleukin(IL)-1β,tumour necrosis factor alpha,IL-6,IL-2 and C-C motif ligand 2 levels were decreased and hepatic impairment was mitigated.In mice with GSDMD knockout,p53 was reduced,GPX4 was increased,and ferroptotic events(depletion of SLC7A11,elevation of ACSL4,and iron accumulation)were detected.In vitro,knockdown of p53 and overexpression of GPX4 reduced AST and ALT levels,the cytostatic rate,and GSDMD expression,restoring SLC7A11 depletion.Moreover,SIRT1 agonist and overexpression of SIRT1 alleviated acute liver injury and decreased iron deposition compared with results in the model group,accompanied by reduced p53,GSDMD,and ACSL4,and increased SLC7A11 and GPX4.Inactivation of SIRT1 exacerbated ferroptotic and pyroptotic cell death and aggravated liver injury in LPS/D-GalNinduced in vitro and in vivo models.CONCLUSION SIRT1 activation attenuates LPS/D-GalN-induced ferroptosis and pyroptosis by inhibiting the p53/GPX4/GSDMD signaling pathway in ALF.

The effect of glutathione on glucosinolate biosynthesis through the sulfur assimilation pathway in pakchoi associated with the growth conditions

Glucosinolates(GSLs) are a group of nitrogen-and sulfur-containing secondary metabolites, synthesized primarily in members of the Brassicaceae family, that play an important role in food flavor, plant antimicrobial activity, resistance to insect attack, stress tolerance, and human anti-cancer effects. As a sulfur-containing compound, glutathione has a strong connection with GSLs biosynthesis as a sulfur donor or redox system, and exists in reduced(glutathione;GSH) and oxidized(glutathione disulfide;GSSG) forms. However, the mechanism of GSH regulating GSLs biosynthesis remainds unclear. Hence, the exogenous therapy to pakchoi under normal growth condition and sulfur deficiency condition were conducted in this work to explore the relevant mechanism. The results showed that exogenous application of buthionine sulfoximine, an inhibitor of GSH synthesis, decreased the transcript levels of GSLs synthesis-related genes and transcription factors, as well as sulfur assimilation-related genes under the normal growth condition. Application of exogenous GSH inhibited the expression of GSLs synthesis-and sulfur assimilation-related genes under the normal condition, while the GSLs biosynthesis and the sulfur assimilation pathway were activated by exogenous application of GSH when the content of GSH in vivo of plants decreased owing to sulfur deficiency. Moreover,exogenous application of GSSG increased the transcript levels of GSLs synthesis-and sulfur assimilation-related genes under the normal growth condition and under sulfur deficiency. The present work provides new insights into the molecular mechanisms of GSLs biosynthesis underlying glutathione regulation.

Dietary glycine supplementation enhances syntheses of creatine and glutathione by tissues of hybrid striped bass(Morone saxatilis ♀ × Morone chrysops ♂) fed soybean meal-based diets

Background We recently reported that supplementing glycine to soybean meal-based diets is necessary for the optimum growth of 5-to 40-g(Phase-I)and 110-to 240-g(Phase-II)hybrid striped bass(HSB),as well as their intestinal health.Although glycine serves as an essential substrate for syntheses of creatine and glutathione(GSH)in mammals(e.g.,pigs),little is known about these metabolic pathways or their nutritional regulation in fish.This study tested the hypothesis that glycine supplementation enhances the activities of creatine-and GSH-forming enzymes as well as creatine and GSH availabilities in tissues of hybrid striped bass(HSB;Morone saxatilis♀×Morone chrysops♂).Methods Phase-I and Phase-II HSB were fed a soybean meal-based diet supplemented with 0%,1%,or 2%glycine for 8 weeks.At the end of the 56-d feeding,tissues(liver,intestine,skeletal muscle,kidneys,and pancreas)were collected for biochemical analyses.Results In contrast to terrestrial mammals and birds,creatine synthesis occurred primarily in skeletal muscle from all HSB.The liver was most active in GSH synthesis among the HSB tissues studied.In Phase-I HSB,supplementation with 1%or 2%glycine increased(P<0.05)concentrations of intramuscular creatine(15%–19%)and hepatic GSH(8%–11%),while reducing(P<0.05)hepatic GSH sulfide(GSSG)/GSH ratios by 14%–15%,compared with the 0-glycine group;there were no differences(P>0.05)in these variables between the 1%and 2%glycine groups.In Phase-II HSB,supplementation with 1%and 2%glycine increased(P<0.05)concentrations of creatine and GSH in the muscle(15%–27%)and liver(11%–20%)in a dose-dependent manner,with reduced ratios of hepatic GSSG/GSH in the 1%or 2%glycine group.In all HSB,supplementation with 1%and 2%glycine dose-dependently increased(P<0.05)activities of intramuscular arginine:glycine amidinotransferase(22%–41%)and hepaticγ-glutamylcysteine synthetase(17%–37%),with elevated activities of intramuscular guanidinoacetate methyltransferase and hepatic GSH synthetase and GSH reductase in the 1%or 2%glycine group.Glycine supplementation also increased(P<0.05)concentrations of creatine and activities of its synthetic enzymes in tail kidneys and pancreas,and concentrations of GSH and activities of its synthetic enzymes in the proximal intestine.Conclusions Skeletal muscle and liver are the major organs for creatine and GSH syntheses in HSB,respectively.Dietary glycine intake regulates creatine and GSH syntheses by both Phase-I and Phase-II HSB in a tissue-specific manner.Based on the metabolic data,glycine is a conditionally essential amino acid for the growing fish.

Characterization of the dissociation pathways of dichloromethane and glutathione in dichloromethane dehalogenase

Dichloromethane(DCM)dehalogenase stands as a crucial enzyme implicated in the degradation of methylene chloride across diverse environmental and biological contexts.However,the unbinding pathways of ligands from DCM dehalogenase remain unexplored.In order to gain a deeper understanding of the binding sites and dissociation pathways of dichloromethane(DCM)and glutathione(GSH)from the DCM dehalogenase,random accelerated molecular dynamics(RAMD)simulations were performed,in which DCM and GSH were forced to leave the active site.The protein structure was predicted using Alphafold2,and the conformations of GSH and DCM in the binding pocket were predicted by docking.A long equilibrium simulation was conducted to validate the structure of the complex.The results show that GSH is most commonly observed in three main pathways,one of which is more important than the other two.In addition,DCM was observed to escape along a unique pathway.The key residues and protein helices of each pathway were identified.The results can provide a theoretical foundation for the subsequent dissociation mechanism of DCM dehalogenase.

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.

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.

弱光及干旱条件下AMF对切花月季光合和AsA-GSH循环的影响

旨在探究弱光及干旱条件下丛枝菌根真菌(AMF)对切花月季光合、AsA-GSH循环以及渗透调节物质的影响。盆栽条件下设置100%全光照(L1)、50%全光照(L2)2个光照处理组,80%土壤持水量(W1)和40%土壤持水量(W2)2个水分处理组,接种AMF[变形球囊霉(Glomus versiforme)+异形根孢囊霉(Rhizophagus irregularis)]及不接种对照(CK)共8个处理。结果表明,AMF能够侵染切花月季根系,显著提高切花月季生长品质。弱光和/或干旱胁迫下,与不接种对照相比,接种AMF能有效地促进切花月季叶片的净光合速率(P_(n))、蒸腾速率(T_(r))、气孔导度(G_(s))和水分利用效率(WUE)增加,降低细胞间隙CO_(2)浓度(C_(i));在L2W2处理条件下,与不接种对照相比,接种AMF使切花月季叶片中的抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)、单脱氢抗坏血酸还原酶(MDAR)和脱氢抗坏血酸还原酶(DHAR)活性分别提高5.2%、15.4%、21.7%和35.9%;接种AMF的抗坏血酸(AsA)含量与对照处理无显著差异,还原型谷胱甘肽(GSH)含量提高8.1%,GSH/GSSG比值增加7.9%;接种AMF后切花月季丙二醛(MDA)含量显著降低,可溶性糖、可溶性蛋白和脯氨酸(Pro)含量明显增加。结论认为AMF通过维持AsA/DHA和GSH/GSSG的稳定,提高AsA-GSH循环中相关酶活性,增加切花月季叶片可溶性糖、可溶性蛋白和脯氨酸含量而降低MDA含量来适应水分和光照的变化,形成适应光照和水分条件变化的生理生态对策来改善切花月季生长品质。

干旱胁迫下外源褪黑素对王族海棠光合作用、ASA-GSH循环以及激素变化的影响

为探究干旱胁迫下外源褪黑素(MT)对王族海棠(Malus‘Royalty’)生长状况、光合作用、激素代谢以及抗坏血酸-谷胱甘肽(ASA-GSH)循环生理的影响,盆栽条件下设置正常水分(CK)、干旱胁迫(DS)以及干旱胁迫下叶片喷施6个质量分数(50、100、150、200、250、300 mg/kg,分别记为MT1、MT2、MT3、MT4、MT5、MT6)的褪黑素,共8个处理,分析干旱胁迫下不同质量分数褪黑素处理对王族海棠生长量、叶绿素含量、光合参数、激素代谢以及ASA-GSH循环中相关酶活性和抗氧化物质含量的影响。结果表明,与DS处理相比,DS+MT3处理下的株高、基径、总干质量、根系总体积以及根系平均直径分别增加54.7%、20.0%、143.2%、33.5%、6.9%;叶绿素a、叶绿素b以及类胡萝卜素含量分别增加20.5%、115.7%和83.0%;光合参数中净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)以及水分利用效率(WUE)分别增加51.8%、110.9%、55.5%和96.6%,且Pn恢复至CK水平,胞间CO_(2)浓度(Ci)和气孔限制值(Ls)则分别下降43.3%和57.0%;PSⅡ最大光化学量子效率(Fv/Fm)、PSⅡ潜在活性(Fv/Fo)、PSⅡ实际光化学量子效率(ΦPSⅡ)以及PSⅡ有效光化学量子效率(Fv′/Fm′)分别增加5.4%、61.8%、171.6%和168.7%。王族海棠AsA-GSH循环中抗坏血酸过氧化物酶(APX)、脱氢抗坏血酸还原酶(DHAR)、单脱氢抗坏血酸还原酶(MDHAR)以及谷胱甘肽还原酶(GR)活性分别增加168.3%、90.4%、167.2%和126.0%;抗坏血酸(ASA)含量、谷胱甘肽(GSH)含量、抗坏血酸/脱氢抗坏血酸(ASA/DHA)、还原型/氧化型谷胱甘肽(GSH/GSSG)分别增加102.5%、67.5%、129.8%和342.1%;生长素(IAA)、赤霉素(GA)、玉米素核苷(ZR)含量分别增加26.2%、24.6%和89.3%,脱落酸(ABA)含量降低49.0%。干旱胁迫下,王族海棠的生长参数、光合作用以及ASA-GSH循环过程受到抑制,激素平衡遭到破坏。叶片喷施不同质量分数的褪黑素能够调节内源激素的代谢水平,提高光合作用,增强ASA-GSH循环中相关酶活性以及抗氧化物质含量,促进光合色素的合成和积累,改善叶绿素荧光参数,进而提高植物的生物量,增强王族海棠的抗旱能力,其中以叶片喷施150 mg/kg的褪黑素提高王族海棠的抗旱性效果最好。

DMMIC derivatization-assisted liquid chromatography-mass spectrometry method for metabolite profiling of the glutathione anabolic pathway in esophageal cancer tissues and cells

In this work,a new pyrylium derivatization-assisted liquid chromatography-mass spectrometry(LC-MS)method was developed for metabolite profiling of the glutathione anabolic pathway(GAP)in cancer tissues and cells.The pyrylium salt of 6,7-dimethoxy-3-methyl isochromenylium tetrafluoroborate(DMMIC)was used to label the amino group of metabolites,and a reductant of dithiothreitol(DTT)was employed to stabilize the thiol group.By combining DMMIC derivatization with LC-MS,it was feasible to quantify the 13 main metabolites on the GAP in complex biological samples,which had good linearity(R^(2)=0.99810.9999),precision(interday precision of 1.6%e19.0%and intraday precision of 1.4%e19.8%)and accuracy(83.4%-115.7%).Moreover,the recovery assessments in tissues(82.5%e107.3%)and in cells(98.1%e118.9%)with GSH-^(13)C2,^(15)N,and Cys-^(15)N demonstrated the reliability of the method in detecting tissues and cells.Following a methodological evaluation,the method was applied successfully to investigate difference in the GAP between the carcinoma and para-carcinoma tissues of esophageal squamous cell carcinoma(ESCC)and the effect of p-hydroxycinnamaldehyde(CMSP)on the GAP in KYSE150 esophageal cancer cells.The results demonstrate that the developed method provides a promising new tool to elucidate the roles of GAP in physiological and pathological processes,which can contribute to research on drugs and diseases.

类风湿关节炎患者外周血单个核细胞System Xc-/GSH/GPX4铁死亡通路的表达及其对炎症因子分泌的影响

目的探讨类风湿关节炎(RA)患者外周血单个核细胞(PBMC)胱氨酸/谷氨酸逆转运体(System Xc-)/谷胱甘肽(GSH)/谷胱甘肽过氧化物酶4(GPX4)铁死亡通路中相关基因与蛋白的表达及其对炎症因子分泌的影响。方法纳入RA患者及同期健康体检者各30例,采用Ficoll-hypaque密度梯度离心法分离PBMC,将细胞分为健康对照、RA、铁死亡抑制剂、铁死亡诱导剂组。采用细胞计数试剂盒8(CCK-8)检测细胞活力,流式细胞术FerroOrange荧光探针检测细胞内Fe 2+相对荧光强度、DHE荧光探针检测细胞内活性氧(ROS)阳性细胞比例,蛋白免疫印迹及实时荧光定量PCR(qPCR)检测核转录因子红系2相关因子(Nrf2)、溶质载体家族7成员11(SLC7A11)、GPX4蛋白与mRNA的表达,流式细胞术检测细胞上清液中肿瘤坏死因子α(TNF-α)、白细胞介素(IL)-1、IL-6的含量。结果与健康对照组比较,RA组PBMC内Fe 2+浓度和ROS水平升高,Nrf2、SLC7A11、GPX4蛋白和mRNA的表达降低,PBMC上清液中TNF-α、IL-1、IL-6的含量升高,差异均有统计学意义。与RA组比较,铁死亡抑制剂组PBMC内Fe 2+浓度和ROS水平降低,SLC7A11、GPX4蛋白和mRNA的表达升高,Nrf2蛋白的表达升高,PBMC上清液中IL-6的含量降低、TNF-α的含量升高,差异均有统计学意义。与RA组比较,铁死亡诱导剂组PBMC内ROS水平升高,SLC7A11蛋白和mRNA的表达降低,Nrf2蛋白的表达降低、GPX4蛋白的表达升高,PBMC上清液中TNF-α、IL-1的含量升高,差异有统计学意义。与铁死亡诱导剂组比较,RA患者PBMC细胞活力降低,差异有统计学意义(P<0.0001)。结论RA患者PBMC中存在铁死亡,抑制或诱导RA患者PBMC铁死亡,将抑制或促进炎性因子分泌。抑制RA患者PBMC铁死亡可能有助于治疗RA。

当归黄芪超滤物通过调控ROS/GSH/GPx4轴抑制铁死亡改善放射性大鼠心肌纤维化

目的探讨ROS/GSH/GPx4轴介导的心肌铁死亡在放射性心肌纤维化中的作用机制及当归黄芪超滤物的干预作用。方法50只大鼠随机分为5组。除空白组外,其余各组大鼠均接受X射线单次局部胸部照射建立放射性心肌纤维化模型。辐射后,当归黄芪超滤物各组大鼠分别灌胃给药30 d后,用小动物超声评价心功能;比色法检测SOD、GSH、MDA及Fe^(2+)活性;免疫荧光检测ROS表达;HE、Masson染色观察病理变化及纤维化;透射电镜观察心肌超微结构;Western blot检测铁死亡及纤维化蛋白表达。结果与空白组比较,模型组LVEF和LVFS值降低;Fe^(2+)、MDA、ROS水平上升,SOD、GSH水平下降;HE及Masson显示有炎性细胞聚集及胶原纤维沉积;透射电镜显示受损线粒体数量增多、排列紊乱,形态不规则、变小、嵴紊乱;Western blot显示α-SMA、Collagen I、NOX1蛋白表达升高,GPx4、FTH1蛋白表达降低;与模型组比较,当归黄芪超滤物组大鼠心功能改善,ROS、抗氧化指标恢复,Fe^(2+)水平降低;线粒体结构及纤维化程度减轻;α-SMA、Collagen I、NOX1蛋白表达下降,GPx4、FTH1蛋白表达上升。结论当归黄芪超滤物对放射性心肌纤维化具有抑制作用,其机制可能是通过调控ROS/GSH/GPx4轴抑制心肌铁死亡发挥作用。

石榴果皮As A-GSH循环系统对日灼的响应

为探明石榴果皮日灼发生过程中抗坏血酸(AsA)-谷胱甘肽(GSH)循环系统的响应,以日灼高感品种‘红玉石籽’为材料,分析了不同程度日灼果皮中As A、GSH含量以及H_(2)O_(2)和O_(2)^(-)·含量的变化,以及日灼果实果皮中谷胱甘肽代谢途径中代谢物的变化和关键酶基因表达的变化。结果表明,日灼引起石榴果皮中H_(2)O_(2)和O_(2)^(-)·含量显著上升;日灼果皮中GSH含量显著升高,而As A含量只有在严重日灼发生时显著升高;日灼导致石榴果皮谷胱甘肽代谢通路中13种代谢物的含量发生变化,其中4种代谢物的含量显著上调,9种代谢物的含量显著下调;Pgr-GR-2的表达量随着日灼程度增加显著上升,但严重日灼(SB3)果皮的Pgr-GR-2表达量比中度日灼(SB2)时略有降低;在受到轻微日灼(SB1)时,Pgr-APX-3和Pgr-DHAR-1的表达量显著升高,但是随着日灼程度的加深,其表达量呈下降趋势。Pgr-MDHAR-1的表达量随着日灼程度的加重呈现下降趋势,在日灼程度达到SB3时,Pgr-MDHAR-1的表达量显著低于无日灼果实。研究表明日灼激活了石榴果皮As A-GSH循环中Pgr-GR-2、Pgr-APX-3和Pgr-DHAR-1基因的表达,抑制Pgr-MDHAR-1基因的表达,进一步引起AsA和GSH含量的增加,以清除H_(2)O_(2)和O_(2)^(-)·增加带来的损伤。研究结果为石榴果实日灼机理的探究以及日灼的防治提供了理论依据。

N-acetylcysteine and reduced glutathione reverse flupirtine-induced liver injury and pro⁃duce other beneficial effects in combination with flupirtine

OBJECTIVE To assess whether N-acetylcysteine(NAC)and reduced glutathione(GSH)are effective in reversing flupirtine-induced hepatotoxicity and whether they have other beneficial effects when combined with flupirtine.METHODS The analgesic effects of NAC and flupirtine were first evaluated in carrageenaninduced inflammatory pain and paclitaxel-induced neuropathic pain.The combination subthreshold⁃ing approach was then used to determine whether the combination of NAC and flupirtine produced synergistic analgesic effects.Hepatotoxicity markers and histopathological examination of the liver were used to assess the efficacy of NAC and GSH in reversing flupirtine-induced hepato⁃toxicity.Finally,the effect of GSH on the safe range of flupirtine was assessed in an acute tox⁃icity assay.RESULTS Flupirtine and NAC pro⁃duced dose-dependent antiallodynic effects evoked by carrageenan and paclitaxel in mice.In the above model,the combination of NAC and flupirtine produced an unexpected synergistic analgesic effect.There were no significant differ⁃ences observed in the hepatotoxicity markers and liver histopathology between the experimen⁃tal group and the control group under NAC and GSH treatment.Finally,GSH(200 mg·kg^(-1))expanded the therapeutic index of flupirtine by 1.77 times.CONCLUSION NAC and GSH are effective in preventing liver damage caused by long-term flupirtine use,which provides a solu⁃tion for the safe and effective treatment of chronic pain with flupirtine.In addition,the other benefi⁃cial effects of NAC and GSH when combined with flupirtine may provide the basis for the devel⁃opment of a new therapy with minimal sideeffects and good efficacy.

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.

Evaluation of Glutathione Peroxidase Enzymatic Activity in Seminal Plasma of Patients Treated at the Institute Pasteur in Cote d’Ivoire

Glutathione peroxidase (GPx) is an antioxidant that plays an important role in the maintenance of male fertility. The aim of this study was to compare the profile of enzymatic activity of glutathione peroxidase in the seminal plasma of normozoosperm and those of pathological sperm. Thus, the activity of glutathione peroxidase was determined in the seminal plasma of 20 normozoosperms, 9 azoosperms and 31 oligoasthenoteratozoosperms. It was 37.58 ± 3.14 U/L in normozoosperms, 39.39 ± 2.27 U/L in oligoasthenoteratozoosperms, and 29.77 ± 2.62 U/L in azoosperms. The mean GPx enzyme activity of normozoosperms did not differ significantly from that of oligoasthenoteratozoosperms and azoosperms. In contrast, comparison of enzyme activity between abnormal sperms gave a significant difference. This study showed that glutathione peroxidase enzymatic activity is not related to sperm quality.

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.

Electronic Aspects of the Synergistic Antioxidant Interaction of Various Pairs “Phenolic Food Acid and Glutathione” in Their Reactions with the Stable Radical Cation ABTS+·

In the present work, for the first time, the main details of the electronic mechanism of the synergistic antioxidant interaction between different pairs: phenolic food acid and glutathione and the stable radical cation ABTS+· were revealed on the basis of a rigorous analysis of the DFT calculated data. It was shown that among all the studied food acids, only caffeic acid exhibits a clear-cut significant synergistic effect with glutathione. It established the electronic and structural factors underlying the mechanism of the synergistic interaction of the mixture caffeic acid and glutathione in its reaction with ABTS+·. The main causes of this considered synergistic effect are, firstly, the presence of the 3-OH and 4-OH hydroxyl groups in the structure of caffeic acid, secondly, the greater stability of its anion which contains the deprotonated 4-OH hydroxyl group. All other phenolic food acids under study do not possess the given structural particularity and therefore do not show such synergistic effects with glutathione.

Evaluation of combined detection of nuclear factor erythroid 2-related factor 2 and glutathione peroxidase 4 in primary hepatic carcinoma and preliminary exploration of pathogenesis

This study aims to analyze the clinical significance and mechanism of nuclear factor erythroid 2-related factor 2(NRF2)and glutathione peroxidase 4(GPX4)in primary hepatic carcinoma(PHC).Methods:The expression of NRF2 and GPX4 in peripheral blood of patients with PHC was determined to analyze the diagnostic value of the two combined for PHC.The prognostic significance of NRF2 and GPX4 was evaluated by 3-year followup.Human liver epithelial cells THLE-2 and human hepatocellular carcinoma cells HepG2 were purchased,and the expression of NRF2 and GPX4 in the cells was determined.NRF2 and GPX4 aberrant expression vectors were constructed and transfected into HepG2,and changes in cell proliferation and invasion capabilities were observed.Results:The expression of NRF2 and GPX4 in patients with PHC was higher than that in patients with LC or VH(p<0.05),and the two indicators combined was excellent in diagnosing PHC.Moreover,patients with high expression of NRF2 and GPX4 had a higher risk of death(p<0.05).In in vitro experiments,both NRF2 and GPX4 expression was elevated in HepG2(p<0.05).HepG2 activity was enhanced by increasing the expression of the two,vice versa(p<0.05).Conclusion:NRF2 and GPX4 combined is excellent in diagnosing PHC,and promotes the malignant development of PHC.

Glutathione peroxidase mimicry of diphenyl diselenide: Plausible contribution of proteins’ thiols

Organoseleniums are a class of compounds attracting attention across the globe owing to their Glutathione peroxidase(GPx)mimicry,which confers on them a strong antioxidant activity.Diphenyl diselenide(DPDS)is an Organoselenium whose GPx mimetic property has been suggested to rely on the oxidation of non-protein or protein thiols critical to the activities of some sulfhydryl enzymes.This study,therefore investigated the GPx mimic/antioxidant property of DPDS as well as the role of thiols of two key sulfhydryl enzymes,cerebral Na^(+)/K^(+)-ATPase(sodium pump)and hepatic delta-aminolevulinic acid dehydratase(δ-ALAD)in the GPx mimicry of DPDS.Albino Wistar rats were euthanized,and the liver and brain were removed and used to assay for the effect of DPDS on lipid peroxidation induced by two prooxidants[Fe2^(+)(10μM)and H2O2,(1 mM)]as well as the activities of the sulfhydryl enzymes.The results revealed that DPDS profoundly(P<0.05)counteracted Fe2^(+)and H2O2-induced lipid peroxidation in the rats’hepatic and cerebral tissues.Furthermore,the results of assay systems for lipid peroxidation and sodium pump revealed that DPDS inhibited Na^(+)/K^(+)-ATPase and lipid peroxidation in the brain tissue homogenates in the same reaction system.A similar result was obtained in the assay system for lipid peroxidation and hepaticδ-ALAD as DPDS simultaneously inhibited the enzyme’s activity and lipid peroxidation.This suggests that the GPx mimetic property of DPDS may be linked to the enzymes’loss of activity,which further validates the suggestions that the enzymes’inhibition,as well as the antioxidant action of DPDS,rely on the oxidation of critical thiols of the enzymes.However,the GPx mimicry of DPDS should be investigated in the presence of thiol-blocking or oxidizing agents in biological systems in order to further ascertain the role of protein thiols.

碱胁迫下内生真菌共生对布顿大麦抗氧化酶和ASA-GSH循环的影响

内生真菌能够提高宿主植物的抗逆性,而碱胁迫使植物体内积累大量的活性氧,加速植物衰老和死亡。为探究碱胁迫下内生真菌对宿主布顿大麦抗氧化酶和抗坏血酸-谷胱甘肽(ASA-GSH)循环系统的影响,本试验以带内生真菌(E+)和不带内生真菌(E-)的布顿大麦为材料,设置0、25、50、100、150、200 mmol/L混合碱(Na_(2)CO_(3)+NaHCO_(3))胁迫处理,研究碱胁迫下内生真菌对布顿大麦过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性及叶片ASA-GSH循环中抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)、谷胱甘肽过氧化物酶(GPX)活性和谷胱甘肽(GSH)含量变化的影响。结果表明,在碱胁迫下,抗氧化酶和ASA-GSH循环系统均受内生真菌影响,E+布顿大麦中的POD和GR活性低于E-布顿大麦,而CAT、SOD和APX活性及GSH含量显著高于E-布顿大麦;低浓度碱胁迫下,E+布顿大麦叶片的GPX活性高于E-布顿大麦,但当碱浓度大于100 mmol/L时,则表现为E-高于E+。说明碱胁迫下内生真菌能够提高布顿大麦的抗氧化性,改变ASA-GSH循环,增强植株的抗逆性。本研究结果可为合理利用内生真菌进行布顿大麦抗逆新种质创新和新品种选育提供理论基础。