黄河鲤谷胱甘肽对氨氮胁迫的生理响应

[目的]研究氨氮对鲤幼鱼肝组织谷胱甘肽及其酶系的影响,阐析谷胱甘肽对环境胁迫的抗氧化防御机理.[方法]将黄河鲤在对照组(0 mg/L)和低(10 mg/L)、中(20 mg/L)、高(30 mg/L)3个氨氮处理组中染毒,研究氨氮胁迫6、24和48h后对肝组织中谷胱甘肽(GSH)含量、谷胱甘肽过氧化物酶(GSH-Px)和谷胱甘肽转移酶(GST)活性的影响.[结果]氨氮胁迫诱导黄河鲤幼鱼肝组织中GSH含量、GSH-Px和GST活性迅速升高,并在氨氮胁迫24h达到最大值,从而抵御氨氮造成的氧化胁迫.随着氨氮胁迫时间的延长,肝组织中GSH含量、GSH-Px和GST活性降低,抗氧化能力减弱.[结论]氨氮胁迫诱导黄河鲤幼鱼肝组织中谷胱甘肽含量及其酶系活性改变,以有效清除细胞中的活性氧和有毒代谢物,提高鱼类对环境的适应性.     

BTH-mediated antioxidant system responses in apple leaf tissues

BTH (S-methylbenzo-1,2,3-thiadiazole-7-carbothiate), an active compound of the commercial preparation Bion, has been studied as an elicitor of resistance to fire blight (Erwinia amylovora) in apple. However, the biochemical mechanisms of its action are not fully elucidated. Our study indicated that BTH at the best time of its protection activity (2–14 days after application) induced changes in prooxidant–antioxidant balance in the leaves of apple trees, but in different ways in the enzymatic and nonenzymatic antioxidants. Glutathione as low molecular antioxidant as well as superoxide anion radical and lipid peroxides as oxidants exhibited changes at the early phase of BTH action. Glutathione-dependent enzymes were strongly affected by the elicitor used. On the 2nd day glutathione transferase (GST) and glutathione peroxidase (GSH-Px) activities increased by about 70% and 30% above the control, respectively. GST activity normalized about the 14th day but GSH-Px at the same time showed 27% of the control value. Among enzymes utilising hydrogen peroxide only catalase showed increase (37%) at the early phase of experiment. Compared with the control, BTH-treated plants did not show changes in ascorbate peroxidase and phenylalanine ammonia-lyase activities. Tocopherol (TOC) level diminished starting from the 7th day after BTH treatment and on the 14th day it was only 28% of the control. It is proposed that extinguishing of BTH-mediated signal resulted from TOC and glutathione action. The diminished ascorbate level at all examined times may play a crucial role in BTH-mediated cell growth regulation. The direct influence of BTH on lipid metabolism should be also taken into consideration.     

BDE-47胁迫对双齿围沙蚕抗氧化防御系统的影响

将双齿围沙蚕Perinereis aibuhitensis暴露在BDE-47下进行急性毒性试验,测定96h-LC_(50)。在此基础上,研究了暴露在0、2、4、8mg·L~(-1)的BDE-47污染物下,双齿围沙蚕的谷胱甘肽(GSH)含量、谷胱甘肽过氧化物酶(GPx)活力、超氧化物歧化酶(SOD)活力、过氧化氢酶(CAT)活力以及丙二醛(MDA)含量、谷胱甘肽硫转移酶(GST)活力的变化情况。结果表明BDE-47对双齿围沙蚕的96h-LC_(50)为31.24mg·L~(-1)。在暴露期间,与对照组比较,各处理组的GSH含量、GST活力、CAT活力总体上无显著变化,仅8mg·L~(-1)组的GST活力在14d极显著性升高(P0.01)。暴露1d时,4mg·L~(-1)处理组GPx活力显著升高(P0.05),在第7~14d时,2mg·L~(-1)处理组的GPx活性呈上升趋势;在暴露1d时,4 mg·L~(-1)、8 mg·L~(-1)两组的SOD活力显著下降(P0.05),整体上看,在1~7d时,SOD活力被诱导升高。14d时,与对照组的比较,4、8mg·L~(-1)处理组的SOD活力分别被显著(P0.05)和极显著(P0.01)抑制。在暴露1d时,MDA含量被诱导升高(P0.05),且4mg·L~(-1)极显著升高(P0.01)。在暴露4~14dMDA含量总体上无明显变化,仅第7d的8mg·L~(-1)处理组显著升高(P0.05)。结论:在双齿围沙蚕抗氧化防御系统中,MDA含量和SOD活力均在胁迫初期有显著变化,因此MDA含量和SOD活力可以作为潜在的生物标志物。     

谷胱甘肽对切花月季‘Samantha’失水胁迫耐性的影响

采用外源谷胱甘肽（GSH）及其生物合成关键酶γ–谷氨酰半胱氨肽合成酶（γ-ECS）的专一抑制剂丁胱亚磺酰胺（BSO）分别处理切花月季‘Samantha’花枝基部,以提高或降低花瓣中的GSH含量,研究GSH对月季切花失水胁迫耐性的影响,以及花瓣中抗坏血酸–谷胱甘肽（AsA-GSH）循环对失水胁迫的响应。结果表明：提高花瓣中GSH的含量,明显提高了失水胁迫24 h后切花的复水率,延长了瓶插寿命;相反,BSO预处理降低了花瓣中的GSH含量,从而降低了切花的失水胁迫耐性。GSH预处理在明显提高失水胁迫和复水期间花瓣中GSH总含量和还原型GSH含量的同时也提高了抗坏血酸（AsA）的含量;AsA-GSH循环中两个关键酶抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）的活性也明显高于胁迫对照,并且MDA的含量明显降低。BSO预处理则产生相反的效果。这些结果表明,GSH能够通过提高AsA-GSH循环的抗氧化能力来增强月季切花的失水胁迫耐性。     

谷胱甘肽对小麦幼苗铜毒害的缓解作用及其与氮、硫、磷积累的相关性

采用水培法,对外源谷胱甘肽(GSH)缓解小麦幼苗铜毒害及其与氮、硫、磷等元素积累的相关性进行了研究。结果表明,Cu处理(T0组)显著抑制小麦幼苗的生长发育,导致根长、茎叶长、生物量、叶绿素和类胡萝卜素含量以及氮元素积累量下降,诱导了植株蛋白质、内源GSH含量以及硫、磷元素积累量上升。随施用外源GSH浓度的升高,GSH处理(T1、T2、T3组)的小麦幼苗茎叶长、根长、生物量,叶绿素a、b和类胡萝卜素含量、蛋白质含量先上升后下降,内源GSH含量以及氮、硫、磷等营养元素积累量持续上升;其中,T2组小麦幼苗的各项指标与T0组差异均达到显著水平(P<0.05),与对照组(CK)无显著差异。外源GSH促进了植株对铜离子的吸收、转运和积累,而外源和内源GSH均与铜胁迫下小麦幼苗氮、硫、磷等营养元素的积累呈极显著正相关(P<0.01),其中以T2处理组缓解小麦幼苗铜毒害的作用最显著。     

Effect of methyl parathion and chlorpyrifos on certain biomarkers in various tissues of guppy fish, Poecilia reticulata

Tests of acute toxicity were performed on the most common species of aquarium fish, Poecilia reticulata. Guppies (P. reticulata) were exposed to progressive concentrations of methyl parathion (MP) and chlorpyrifos (CPF); a semi-static method according to guidelines of OECD was used. Tests of acute toxicity were conducted using 10 fish for each separate concentration and for the control group. The results were subjected to probit analysis to determine the 96 h LC₅₀ values. The 96 h LC₅₀ values of MP and CPF to P. reticulata were 8.48 ppm/L (5.98–10.89) and 0.176 ppm/L (0.313–0.224) respectively. In addition, behavioral changes at each concentration were observed for the individual fish. Fish were exposed for 96 h to different sublethal concentrations of MP and CPF (¼ LC₅₀, 1/8 LC₅₀ and 1/10 LC₅₀) and their oxidative stress-induction potential was estimated in brain, liver and gills of fish. MDA content is induced in all tissues but maximum rise was observed in gills (161% and 153% for MP and CPF respectively). With regard to antioxidant defense system (ADS), GSH level decreased in the brain, liver and gills of tissues of MP treated fishes (22%, 6% and 13% respectively) and showed increase in brain and gills CPF treated (23% and 21% respectively). CAT, GST, GR and SOD levels fluctuated in all treatment groups relative to the control. Brain AChE showed dose-dependent inhibition in fish exposed to the higher concentrations reached 45% and 66% for MP and CPF respectively. Collective findings demonstrated that pesticide exposure of fish induced an increase in MDA and fluctuated ADS along with inhibited AChE. These findings may be used as valuable biomarkers for evaluation of water pollution.     

小鼠溃疡性结肠炎模型的建立与评价

本试验旨在通过筛选葡聚糖硫酸钠盐(DSS)最佳浓度建立小鼠溃疡性结肠炎模型。将30只BALB/c小鼠随机分为对照组、3.5% DSS组、5% DSS组,每组10只。小鼠自由饮水5 d,每天记录小鼠体重,观察粪便性状,测便潜血。试验结束后测血清TNF-α、结肠组织髓过氧化物酶(MPO)、丙二醛(MDA)、还原性谷胱甘肽(GSH)活性变化等指标,计算结肠重量/长度比值。与对照组相比,两试验组结肠组织中MPO活性显著升高(P<0.05),MDA含量显著升高(P<0.05),GSH含量显著降低(P<0.05)。结果表明,两种浓度葡聚糖硫酸钠盐均可造模成功,5% DSS组小鼠精神状态很差,表现嗜睡、萎靡状态,而3.5% DSS组小鼠精神状态良好,且组织中MPO、MDA、GSH与对照组相比均差异显著(P<0.05),与5% DSS组相比差异不显著(P>0.05),因此,选用浓度为3.5% DSS造模更合适。     

水稻谷胱甘肽过氧化物酶的测定法

以水稻幼苗的叶片为材料,用０．２ｍｏｌ／ＬｐＨ６．２的磷酸缓冲液（含１ｍｍｏｌ／Ｌ,ＥＤＴＡ－２Ｎａ５％的水溶性ＰＶＰ）作为谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）的提取介质,偏磷酸为酶促反应的蛋白质沉淀剂,二硫代对二硝基苯甲酸（ＤＴＮＢ）与ＧＳＨ显色反应３ｍｉｎ,在４１２ｎｍ测定酶管和非酶管的ＯＤ值,以测定谷胱甘肽过氧化物酶的活性。     

谷胱甘肽对自毒作用下辣椒叶片光合特性的影响

以当地辣椒(Capsicum annuum L.)主栽品种"陇椒5号"和"七寸红"为试材,研究自毒作用下不同浓度外源谷胱甘肽(GSH)对辣椒幼苗叶绿素含量、光合参数和叶绿素荧光参数的影响,以探讨GSH对辣椒自毒作用的缓解效果和生理作用机制。结果表明:单一叶浸提液处理(CK2)后,2个品种辣椒叶片的叶绿素含量、净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、PSII最大光化学效率(Fv/Fm)、PSII有效光能转化效率(Fv’/Fm’)和实际光化学效率(ФPSII)均较清水处理(CK1)降低,初始荧光(Fo)升高,胞间CO2浓度(Ci)则先升后降。说明辣椒叶浸提液引起的自毒作用导致光合作用的下降主要是由于非气孔因素引起的。含有不同浓度GSH的叶浸提液处理后,叶绿素含量、Pn、Gs、Tr、Fv/Fm、Fv’/Fm’和ФPSII与单一辣椒叶浸提液处理相比均有一定程度的回升,Ci和Fo均较叶浸提液处理的降低。说明外源GSH能够提高自毒作用下辣椒幼苗叶片CO2的利用率,降低非气孔因素的伤害,进而缓解自毒物质对辣椒幼苗的毒害。研究表明,适合缓解陇椒5号和七寸红自毒作用的GSH浓度分别为50和30mg.L-1。     

安全剂R-28725保护玉米免受咪唑乙烟酸药害的机理研究

研究了安全剂R-28725对玉米的保护作用及对咪唑乙烟酸的解毒机理。当咪唑乙烟酸的使用量为20、40、60 g/hm2时,R-28725能够明显提高玉米株高、株鲜重和产量,直接增加植株体内谷胱甘肽(GSH)活性,增加咪唑乙烟酸与谷胱甘肽的轭合,从而达到解毒的目的。