共查询到20条相似文献，搜索用时 281 毫秒
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李玲 《湖南科技学院学报》2012,(9):173-175
在非生物逆境胁迫下,植物体内通过合成与积累渗透调节物质、抗逆相关蛋白质和活性氧的清除酶等来增强植物的抗逆性,这些物质在植物体内通过信号传导和基因表达调控途径构成了一个复杂的调控网络。文章对植物抗非生物逆境的分子机理进行了简要综述。 相似文献
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生物反应的最大特征之一是具有高度的识别能力,一百年前E.Fisher曾以“锁与钥匙”的配合来描述这一现象。生物反应的识别可理解为底物与给定受体选择性的键合。这一过程主要表现在生物分子之间相互作用的高度专一性。专一性在化学及生命过程中起着非常重要的作用,诸如,酶与底物间的专一性使复杂的细胞内代谢井然有序地进行;DNA碱基之间的专一性是构成遗传现象的基础;抗原与抗体反应的专一性使生物体具有识别非自身的异物,并加以排除的免疫功能,特别是信息转录过程中DNA和mRNA间, 相似文献
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陈龙 《周口师范学院学报》1994,(1)
钙调素是在生物体内广泛分布的一种钙结合蛋白,它在不同的生物和组织中分布有较大的变化,在细胞组分内的分布上与它在细胞内的多种调节功能密切相关。钙调素作为Ca~(2 )的细胞内受体影响Ca~(2 )浓度,从而影响依赖Ca~(2 )的多种生理生化过程。它对细胞内多种酶的活性,肌肉收缩,神经递质的合成、释放和传递,细胞的多种运动,卵的受精与细胞分裂,前列腺素和胰岛素的合成与释放等具有调节作用。一些疾病的发生与钙调素代谢失调有关。 相似文献
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人教版高中《生物》第五章第二节“微生物的代谢”内容包括三部分：微生物的代谢产物,微生物代谢的调节,微生物代谢的人工控制。微生物在代谢的基础上才能生长,因此这节内容在本章中是非常关键的,其中涉及了微生物细胞内的两种代谢产物和两种调节方式,阐述了环境中的物质成分是酶合成调节的物质基础,而微生物的代谢产物是酶活性调节的物质基础。学习“微生物的代谢”对进一步理解第一册第三章中植物和动物体内的新陈代谢过程以及本章中微生物营养物质的种类、培养基的配置原则和将要学习的微生物的生长等知识也具有十分重要的作用。 相似文献
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真核细胞内有数万种行使各种功能的蛋白质，在正常代谢条件下，蛋白质的合成和降解有精确的调节而处于动态平衡。内源性的蛋白质都有一定寿命，或长或短，最终命运是被降解。如果蛋白质的降解速率和位点出现异常，就会影响细胞的多种功能，如细胞分裂、信号传递等。目前发现真核细胞内有多条蛋白质降解途径，主要包括溶酶体途径、泛素一蛋白水解酶复合体通路、以及胱天蛋白酶(easpase)水解途径等。现简要介绍这几条途径。 相似文献
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植物体内过氧化氢的产生及其生理作用 总被引：1，自引：0，他引：1
文章概述了过氧化氢(H2O2)在植物体内的产生及其作用机制的研究进展.H2O2作为活性氧之一在许多生命活动中有着广泛的影响,许多生物和非生物胁迫均能导致植物体产生H2O2.多年来,研究一直注重H2O2对植物生长发育方面的影响,它作为信号分子的重要作用直到近几年才越来越多地受到关注. 相似文献
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任雪平 《商丘师范学院学报》2011,27(3):85-88
雌激素是一种多效应激素,对生殖,心血管,骨骼及神经系统的生理功能发挥调节作用.近年研究表明,雌激素还是神经系统中一种重要的信号分子,可改善葡萄糖代谢,保护线粒体ATP合成功能并抑制自由基生成,维持线粒体膜电位以及细胞内钙稳态,从而抑制或减轻氧化应激诱导的神经细胞凋亡或坏死,有效保护神经细胞和组织.线粒体有可能是雌激素神经保护作用的重要靶标,与雌激素神经保护作用有着密切联系. 相似文献
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Abdul Hamid HAFIZAH Zakaria ZAITON Amom ZULKHAIRI Adenan MOHD ILHAM Megat Mohd Nordin NOR ANITA Abdullah Mahdy ZALEHA 《Journal of Zhejiang University. Science. B》2010,11(5):357-365
Endothelial cell death due to increased reactive oxygen species(ROS) may contribute to the initial endothelial injury,which promotes atherosclerotic lesion formation.Piper sarmentosum(PS),a natural product,has been shown to have an antioxidant property,which is hypothesized to inhibit production of ROS and prevent cell injury.Thus,the present study was designed to determine the effects of PS on the hydrogen peroxide(H2O2)-induced oxidative cell damage in cultured human umbilical vein endothelial cells(HUVECs).In this experiment,HUVECs were obtained by collagenase perfusion of the large vein in the umbilical cord and cultured in medium M200 supplemented with low serum growth supplementation(LSGS).HUVECs were treated with various concentrations of H2O2(0-1000 μmol/L) and it was observed that 180 μmol/L H2O2 reduced cell viability by 50% as denoted by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay.Using the above concentration as the positive control,the H2O2-induced HUVECs were concomitantly treated with various concentrations(100,150,250 and 300 μg/ml) of three different extracts(aqueous,methanol and hexane) of PS.Malondialdehyde(MDA),superoxide dismutase(SOD),catalase(CAT) and glutathione peroxidase(GPX) levels showed a significant increase(P0.05) in HUVECs compared to the negative control.However,PS extracts showed a protective effect on HUVECs from H2O2-induced cell apoptosis with a significant reduction in MDA,SOD,CAT and GPX levels(P0.05).Furthermore,PS had exhibited ferric reducing antioxidant power with its high phenolic content.Hence,it was concluded that PS plays a beneficial role in reducing oxidative stress in H2O2-induced HUVECs. 相似文献
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题目：PGC-1α在CH1细胞中通过ATP和ROS调控细胞周期 总被引：2，自引：0，他引：2
Xu-feng Fu Kun Yao Xing Du Yan Li Xiu-yu Yang Min Yu Mei-zhang Li Qing-hua Cui 《Journal of Zhejiang University. Science. B》2016,17(2):136-146
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Evaluation of the antioxidant effects of four main theaflavin derivatives through chemiluminescence and DNA damage analyses 总被引：1，自引：0，他引：1
Theaflavins (TFs) are the dimers of a couple of epimerized catechins, which are specially formed during black tea fermentation.
To explore the differences among four main TF derivatives (theaflavin (TF1), theaflavin-3-gallate (TF2A), theaflavin-3′-gallate (TF2B), and theaflavin-3,3′-digallate (TF3)) in scavenging reactive oxygen species (ROS) in vitro, their properties of inhibiting superoxide, singlet oxygen, hydrogen
peroxide, and the hydroxyl radical, and their effects on hydroxyl radical-induced DNA oxidative damage were systematically
analyzed in the present study. The results show that, compared with (−)-epigallocatechin gallate (EGCG), TF derivatives were
good antioxidants for scavenging ROS and preventing the hydroxyl radical-induced DNA damage in vitro. TF3 was the most positive in scavenging hydrogen peroxide and hydroxyl radical, and TF1 suppressed superoxide. Positive antioxidant capacities of TF2B on singlet oxygen, hydrogen peroxide, hydroxyl radical, and the hydroxyl radical-induced DNA damage in vitro were found.
The differences between the antioxidant capacities of four main TF derivatives in relation to their chemical structures were
also discussed. We suggest that these activity differences among TF derivatives would be beneficial to scavenge different
ROS with therapeutic potential. 相似文献
14.
固体消毒剂过氧化尿素的制备 总被引：1，自引：0，他引：1
刘立华 《唐山师范学院学报》2013,(2):1-3
以尿素和过氧化氢为原料采用湿法合成固体消毒剂过氧化尿素,考察了反应物摩尔配比、反应温度、反应时间等因素对过氧化尿素的收率和活性氧含量的影响,确定了最佳的制备工艺条件：过氧化氢与尿素的反应摩尔配比为1．3：1,反应温度为30℃,反应时间为40min,此时过氧化尿素的收率可达到87．32％,过氧化尿素的活性氧含量可达18．81％。 相似文献
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Juliana FELGUEIRAS Joana Vieira SILVA Margarida FARDILHA 《Journal of Zhejiang University. Science. B》2014,15(1):16-42
Prostate cancer （PCa） incidence and mortality have decreased in recent years. Nonetheless, it remains one of the most prevalent cancers in men, being a disquieting cause of men＇s death worldwide. Changes in many cell signaling pathways have a predominant role in the onset, development, and progression of the disease. These include prominent pathways involved in the growth, apoptosis, and angiogenesis of the normal prostate gland, such as an- drogen and estrogen signaling, and other growth factor signaling pathways. Understanding the foundations of PCa is leading to the discovery of key molecules that could be used to improve patient management. The ideal scenario would be to have a panel of molecules, preferably detectable in body fluids, that are specific and sensitive biomarkers for PCa In the early stages, androgen deprivation is the gold standard therapy. However, as the cancer progresses, it even- tually becomes independent of androgens, and hormonal therapy fails. For this reason, androgen-independent PCa is still a major therapeutic challenge. By disrupting specific protein interactions or manipulating the expression of some key molecules, it might be possible to regulate tumor growth and metastasis formation, avoiding the systemic side effects of current therapies. Clinical trials are already underway to assess the efficacy of molecules specially designed to target key proteins or protein interactions. In this review, we address that recent progress made towards under- standing PCa development and the molecular pathways underlying this pathology. We also discuss relevant molecular markers for the management of PCa and new therapeutic challenges. 相似文献
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INTRODUCTION With the development of industry, more and more pollutants are discharged into environment, among them, phenolic wastes are typical contami-nants considered to be hazardous and top priority toxic pollutants listed by the USEPA. They are toxic even at low concentration. Due to their biorefractory, bioaccumulation and carcinogenic potential, the treatment of these contaminants is very important in environmental protection. Various technologies and processes have been tried … 相似文献
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A novel in-situ electrochemical oxidation method was applied to the degradation of wastewater containing chlorophenol. Under oxygen sparging, the strong oxidant, hydrogen dioxide, could be in-situ generated through the reduction of oxygen on the surface of the cathode. The removal rate ofchlorophenol could be increased 149% when oxygen was induced in the electrochemical cell. The promotion factor was estimated to be about 82.63% according to the pseudo-first-order reaction rate constant (min-1). Important operating parameters such as current density, sparged oxygen rate were investigated.Higher sparged oxygen rate could improve the degradation of chlorophenol. To make full use of oxygen, however, sparged oxygen rate of 0.05 m3/h was adopted in this work. Oxidation-reduction potential could remarkably affect the generation of hydrogen peroxide. It was found that the removal rate of chlorophenol was not in direct proportion to the applied current density. The optimum current density was 3.5 mA/cm2 when initial chlorophenol concentration was 100 mg/L and sparged oxygen rate was 0.05 m3/h. 相似文献
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己二酸的绿色合成探究——绿色化学实验在基础有机化学实验中的应用 总被引：1，自引：0，他引：1
以30%过氧化氢为氧化剂,用钨磷酸催化氧化环己醇合成己二酸,考察了催化剂用量,反应物配比和反应时间对己二酸产率的影响。当反应物物质的量比为钨磷酸：环己醇：过氧化氢=1：250：1125,在一定温度下回流反应4~6h,产率可达到50%;且催化剂可以重复使用。结果表明：本方法操作简单,无污染,符合绿色化学发展的要求,可用于基础有机合成实验。 相似文献
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过氧化氢酶能够催化植物光呼吸、线粒体电子传递及脂肪酸β-氧化等过程中产生的过氧化氢,生成氧气,从而消除其对植物细胞产生的危害．本研究采用钼酸铵法,以绿豆真叶过氧化氢酶粗提液为研究对象,用交变电场处理,研究过氧化氢酶在不同电场下的活性．实验过程中分别选用不同电场频率、不同峰值电压以及不同的电场处理时间。研究其对过氧化氢酶活性的影响．结果表明,电场处理过氧化氢酶能构不同程度的提高过氧化氢酶的活性,且在频率为5MHz,电压为600mV,处理时间为5min条件下酶活性达到理想值,酶活为1．99mmol／（min·g）． 相似文献