首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
三唑酮对绿豆幼苗叶片衰老的延缓作用   总被引:26,自引:0,他引:26  
三唑酮处理可提高离体绿豆(PhaseolusradiatusL.)幼苗叶片叶绿素和蛋白质含量。叶片衰老过程中超氧物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(AsAPOD)活性及抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量降低。20mg/L三唑酮可提高POD、AsAPOD活性和AsA、GSH含量,对SOD、CAT活性无影响。丙二醛(MDA)含量在叶片衰老过程中提高,并与POD、AsAPOD活性和AsA、GSH含量呈显著负相关,三唑酮可降低MDA含量。表明三唑酮有提高植物对膜脂过氧化作用的保护能力,延缓叶片的衰老作用。  相似文献   

2.
低温胁迫下红松幼苗活性氧的产生及保护酶的变化   总被引:80,自引:0,他引:80  
在不同低温胁迫时间下,对红松(Pinus koraiensis Sieb.et.Zucc)幼苗针叶中H2O2、O^-.2、膜脂过氧化产物丙二醛(MDA)、组织自动化氧化速率及保护酶超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(ASP)的动态变化过程进行了测定。结果表明,随着低温胁迫时间的延长,O^-.2产生速率和H2O2含量先上升后下降;MDA的含量呈波  相似文献   

3.
水稻幼苗冷锻炼过程中钙的效应   总被引:29,自引:0,他引:29  
冷锻炼处理提高了水稻(Oryza sativa L.)幼苗叶片中抗氧化剂(还原型谷胱甘肽,GSH;抗坏血酸,AsA)含量和膜保护酶(超氧化物歧化酶,SOD)的活性,同时也提高了可溶性蛋白质中热稳定蛋白的含量。CaCl2 浸种处理对上述冷锻炼的作用有加强的效果,且明显地提高了过氧化氢酶(CAT)和过氧化物酶(POD)的活性。有无CaCl2 处理的冷锻炼处理均减轻冷胁迫引起的GSH 及AsA 含量、SOD 活性及热稳定蛋白质含量的下降程度,有利于幼苗在恢复过程中GSH、AsA、CAT、SOD、POD及热稳定蛋白质水平迅速回升。结合CaCl2 处理的冷锻炼苗在冷胁迫恢复生长时增长迅速,且苗健壮浓绿,说明CaCl2浸种对冷锻炼处理提高水稻幼苗的抗冷力有明显的促进作用,这与CaCl2 浸种结合冷锻炼能更有效的提高细胞膜保护能力有关  相似文献   

4.
动脉平滑肌细胞(sm ooth m uscle cell,SMC)是动脉粥样硬化(atherosclerosis,AS)斑块中的主要细胞,它的增殖在AS形成过程中极其重要.利用体外培养的人主动脉SMC,观察了天然高密度脂蛋白(native high density lipoprotein,N-HDL)及氧化修饰HDL(oxidized HDL,OX-HDL)对培养人主动脉SMC cyclin D1(细胞周期蛋白D1)基因转录表达的影响.结果表明:(1)N-HDL对SMCcyclin D1基因表达无影响(P> 0.05);(2)OX-HDL使SMCcyclin D1基因表达显著增强(P<0.01),其表达量随时间(2、12、24 h)延长而增加.上述结果表明,OX-HDL的致AS作用可能与其刺激SMCcyclin D1基因表达增加有关.  相似文献   

5.
钙对水稻幼苗抗冷性的影响   总被引:3,自引:0,他引:3  
CaCl2浸种提高水稻幼苗叶片中结合态钙、内源抗氧化剂(GSH、AsA)含量和膜保护酶(CAT、SOD和POD)活性,也增加可溶性蛋白质中煮沸稳定蛋白质(boiling-stableprotein)的含量。冷胁迫期间,CaCl2并能减少因冷胁迫引起的GSH、AsA含量,CAT、SOD和POD活性以及煮沸稳定蛋白质下降的程度。在恢复期间,经CaCl2处理的幼苗其GSH、ASA、CAT、SOD和POD以及煮沸稳定蛋白质水平均有回升。  相似文献   

6.
两个品种的大豆叶圆片经10-4mol/L和10-3mol/L的H2O2处理12h后,超氧物歧化酶(SOD)、过氧化氢酶(CAT)与谷胱甘肽还原酶(GR)活性明显增加,但10-2mol/L的H2O2处理却使这些酶活性降低。抗旱性较强的大豆品种小粒豆1号较抗旱性较弱的鲁豆4号能维持较高的叶绿素含量和较高的SOD、CAT及GR活性,对H2O2的抗性较强。50μmol/L的亚胺环已酮(CHM)能消除H2O2对SOD、CAT与GR活性的刺激作用,而同样浓度的放线菌素D(AMD)则不能。  相似文献   

7.
用酶组织化学方法探讨经支气管纤维镜(简称纤支镜)活检组织,对肺癌的早期诊断。包括一氧化氮合酶(NOS)、细胞色素氧化酶(CCO)、乳酸脱氢酶(LDH)、琥珀酸脱氢酶(SDH)、酸性磷酸酶(ACP)等。酶组织化学反应结果显示为肺癌组病人NOS、LDH、CCO、ACP的活性显著增高,分别为强阳性(),少数呈最强阳性();而SOH活性为弱阳性(+),较正常人组显著下降。可疑组病人SDH活性增高呈强阳性()或最强阳性(),但NOS、LDH、ACP的活性较肺癌组下降,分别为弱阳性(+)或中等阳性()。上述结果提示:NOS等活性的变化,可作为提高肺癌早期诊断的重要指标之一。  相似文献   

8.
水杨酸对黄瓜叶片抗氧化剂酶系的调节作用   总被引:27,自引:0,他引:27  
分析了水杨酸(SA)对黄瓜(CucumissativusL.)叶片抗氧化剂酶系活性及活性氧水平的调节作用。不同浓度的SA(0.5mmol/L、1mmol/L、2.5mmol/L、5mmol/L)均能显著地提高被处理叶片超氧化物歧化酶(SOD)和过氧化物酶(POD)活性,而且还能诱导同株的非处理叶片中SOD和POD活性增加。用1mmol/LSA处理第一片真叶,在处理后6~72h,POD活性增加了22%~67%,同株非处理的第二片真叶POD活性增加了14%~86%,但是,在SA处理后3h之前以及处理96h之后,POD活性没有变化。SA能够显著降低超氧物阴离子含量和提高过氧化氢水平,但它对过氧化氢酶(CAT)活性的抑制作用很弱,表明SA提高体内过氧化氢含量的原因主要是通过提高SOD活性而不是抑制CAT活性。同工酶分析表明,SA不能诱导新的SOD同工酶,但可以诱导新的POD同工酶。  相似文献   

9.
抗旱性不同的两个大豆品种对外源H2O2的响应   总被引:17,自引:0,他引:17  
两个品种的大豆叶圆片经10^-4mol/L和10^-3mol/L的H2O2处理12h后,超氧化岐化酶(SOD)、过氧化氢酶(CAT)与谷胱甘肽还原酶(GR)活性明显增加,但10^-2mol/L的H2O2处理却使这些酶活性降低。抗旱性较强的大豆品种小粒豆1号较抗旱性较弱的鲁豆4号能维持较高的叶绿素含量和较高的SOD、CAT及GR活性,对H2O2的抗性较强。50μmol/L的亚胺环已酮(CHM)能消除  相似文献   

10.
对从中国红豆杉的茎来源的愈伤组织经筛选而得的sinenxans高产细胞系Ts19的过氧化物酶(POD)、酯酶(EST)、细胞色素氧化酶(COD)、淀粉酶(AML)、多酚氧化酶(PPO)及超氧化物歧化酶(SOD)的同工酶,可溶性蛋白的含量及电泳谱带、超氧化物歧化酶、多酚氧化酶和苯丙氨酸解氨酶(PAL)的活性作了比较研究。并与培养过程中sinenxans含量的动态变化相比较,探索了这几种同工酶的酶谱和两种酶活性与sinenxans的生物合成的关系。旨在为建立紫杉醇生物合成的中间代谢模型奠定基础。  相似文献   

11.
12.
13.
14.
15.
In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.  相似文献   

16.
17.
18.
Shapes of curves of pH-dependence of reactions   总被引:14,自引:14,他引:0  
A simple case is considered in which the rate of a two-step reaction depends on pH because the intermediate formed in the first step has to gain (or lose) a proton before it can react in the second step, and in which the rate-determining step therefore changes with pH. The curves of reaction rate against pH are shown to be symmetrical, and the sharpest peak possible has a width at half its height of 1.53pH units, i.e. of 2log(3+2 radical2). Any particular curve for this situation proves to be identical with a curve that could be generated for the pH-dependence of a single-step reaction in which the rate is proportional to the concentration of a particular ionic form of a reactant. Curves for the latter situation, however, can have forms impossible for the former case in which the rate-determining step changes, but only if the protonations that activate and deactivate the reactant are co-operative. The peak can then become even sharper, and its width at half its height can fall to 1.14pH units, i.e. to 2log(2+ radical3).  相似文献   

19.
20.
Dietary intakes of tomatoes and tomato products containing lycopene have been shown to be associated with decreased risk of chronic diseases such as cancer and cardiovascular diseases in numerous studies. Serum and tissue lycopene levels have also been inversely related to the risk of lung and prostate cancers. Lycopene functions as a very potent antioxidant, and this is clearly a major important mechanism of lycopene action. In this regard, lycopene can trap singlet oxygen and reduce mutagenesis in the Ames test. However, evidence is accumulating for other mechanisms as well. Lycopene at physiological concentrations can inhibit human cancer cell growth by interfering with growth factor receptor signaling and cell cycle progression specifically in prostate cancer cells without evidence of toxic effects or apoptosis of cells. Studies using human and animal cells have identified a gene, connexin 43, whose expression is upregulated by lycopene and which allows direct intercellular gap junctional communication (GJC). GJC is deficient in many human tumors and its restoration or upregulation is associated with decreased proliferation. The combination of low concentrations of lycopene with 1,25-dihydroxyvitamin D3 exhibits a synergistic effect on cell proliferation and differentiation and an additive effect on cell cycle progression in the HL-60 promyelocytic leukemia cell line, suggesting some interaction at a nuclear or subcellular level. The combination of lycopene and lutein synergistically interact as antioxidants, and this may relate to specific positioning of different carotenoids in membranes. This review will focus on the growing body of evidence that carotenoids have unexpected biologic effects in experimental systems, some of which may contribute to their cancer preventive properties in models of carcinogenesis. Consideration of solubility in vitro, comparison with doses achieved in humans by dietary means, interactions with other phytochemicals, and other potential mechanisms such as stimulation of xenobiotic metabolism, inhibition of cholesterogenesis, modulation of cyclooxygenase pathways, and inhibition of inflammation will be considered. This review will point out areas for future research where more evidence is needed on the effects of lycopene on the etiology of chronic disease.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号