褪黑素在哮喘防治中的作用

褪黑素是由松果体分泌的一种神经内分泌激素,具有节律调节、应激反应和清除自由基等生物学功能。近年研究发现,在哮喘患者体内存在褪黑素分泌及代谢功能紊乱,褪黑素干预研究显现其在哮喘的抗炎、免疫调节等方面具有一定的作用。     

脯氨酸在植物非生物胁迫耐性形成中的作用

植物作为固着生活的有机体,经常暴露在多变且对其生长发育不利的环境条件中,这些生物或非生物的胁迫因子严重影响着植物的生长、发育、生存和分布。脯氨酸在植物抵抗逆境胁迫过程中起着重要的作用。根据国内外的最新研究进展,结合我们的研究成果,对植物体内脯氨酸的代谢途径、渗透调节、抗氧化、分子伴侣、生长发育信号和毒性等方面进行了综述,并对该研究领域作了展望。     

微生物源性抗氧化剂对小鼠抗氧化性能及免疫功能的影响

旨在探究不同剂量的微生物源性抗氧化剂对小鼠抗氧化性能及免疫功能的影响。将60只28日龄雌性昆明小鼠随机分为4组,每组15只。试验组分别以0.5 g/kg bw*d(低)、1.0 g/kg bw*d(中)、1.5 g/kg bw*d(高)的剂量灌喂微生物源性抗氧化剂,每天1次,连续30 d,灌胃容量为0.2 mL/10 g bw*d,对照组灌喂等容量的蒸馏水。30 d后,测定微生物源性抗氧化剂对小鼠抗氧化性能及免疫功能的影响。结果表明,1.0 g/kg bw*d的微生物源性抗氧化剂可以极显著地提高血清中GSH-Px的活力(P<0.01),显著提高T-SOD活力(P<0.05),降低MDA的含量(P>0.05)。而1.5g/kg bw*d的微生物源性抗氧化剂可以极显著地提高血清中IgA的含量(P<0.01)和IL-2水平,以及ConA刺激的脾淋巴细胞转化率(P<0.01),促进脾脏和胸腺的发育(P>0.05)。提示1.0g/kg bw*d的微生物源性抗氧化剂可以显著增强小鼠的抗氧化能力,1.5 g/kg bw*d的微生物源性抗氧化剂可以增强免疫功能。     

铁代谢紊乱与阿尔茨海默病

很多研究表明脑内铁代谢紊乱与阿尔茨海默病有关,但其机理尚需深入探讨。综述这方面近年来的研究进展,特别是结合本实验室的研究结果,对铁代谢紊乱和氧化应激、β-淀粉样蛋白和金属离子代谢紊乱、转铁蛋白和转铁蛋白受体、铁调节蛋白、二价金属离子转运体,及天然抗氧化剂通过调节金属代谢平衡缓解β-淀粉样蛋白的毒性对细胞损伤的保护作用进行了深入讨论,旨在对今后这方面的研究及预防和治疗阿尔茨海默病有所帮助。     

抗氧化剂对皮肤角质细胞体外寿命的影响

考察了抗氧化剂对鼠角质细胞体外培养寿命的影响。实验发现在角质细胞的体外培养过程中添加抗氧化剂有利于延长细胞的寿命,其中效果最好的是巯基乙醇,其次为过氧化氢酶和SOD,但在体外培养过程中,角质细胞生长速率仍然逐渐下降。实验还发现,添加抗氧化剂可在一定程度上提高角质细胞的克隆形成率,减缓细胞衰老速率。同时,通过考察鼠表皮角质细胞衰老动力学,获得了对应于不同抗氧化剂的细胞衰老动力学常数。      

Nitric oxide reduces hydrogen peroxide accumulation involved in water stress-induced subcellular anti-oxidant defense in maize plants

Nitric oxide （NO） is a bioactive molecule involved in many biological events, and has been reported as pro-oxidant as well as anti-oxidant in plants. In the present study, the sources of NO production under water stress, the role of NO in water stress-induced hydrogen peroxide （H2O2） accumulation and subcellular activities of anti-oxidant enzymes in leaves of maize （Zea mays L.） plants were investigated. Water stress induced defense increases in the generation of NO in maize mesphyll cells and the activity of nitric oxide synthase （NOS） in the cytosolic and microsomal fractions of maize leaves. Water stress-induced defense increases in the production of NO were blocked by pretreatments with inhibitors of NOS and nitrate reductase （NR）, suggesting that NO is produced from NOS and NR in leaves of maize plants exposed to water stress. Water stress also induced increases in the activities of the chloroplastic and cytosolic anti-oxidant enzymes superoxide dismutase （SOD）, ascorbate peroxidase （APX）, and glutathione reductase （GR）, and the increases in the activities of anti-oxidant enzymes were reduced by pretreatments with inhibitors of NOS and NR. Exogenous NO increases the activities of water stress-induced subcellular anti-oxidant enzymes, which decreases accumulation of H2O2. Our results suggest that NOS and NR are involved in water stress-induced NO production and NOS is the major source of NO. The potential ability of NO to scavenge H2O2 is, at least in part, due to the induction of a subcellular anti-oxidant defense.     

第二届国际天然抗氧化剂会议在北京召开

第二届国际天然抗氧化剂会议于２００１年６月４ -８日在北京召开。与会代表２８０人,其中有来自美国、英国、法国、德国、意大利、瑞士、新西兰、奥地利、土耳其、俄罗斯、南斯拉夫、以色列、日本、韩国、新加坡、马来西亚、泰国、印度、菲律宾、印度尼西亚、香港、台湾等国家和地区的代表１０５人。会议收到论文１７５篇,其中口头报告１０９篇,墙报７８篇。我国学者提交论文９５篇。国际著名自由基专家ＰｒｏｆｅｓｓｏｒＬｅｓｔＰａｃｋｅｒ、ＣａｔｈｅｒｉｎｅＲｉｃｅ -Ｅｖａｎｓ、Ｈｅｌ ｍｕｔＳｉｅｓ、Ｂａｒｒｙ Ｈａｌｌｉ…     

Carbon Monoxide： A Novel Antioxidant Against Oxidative Stress in Wheat Seedling Leaves

Carbon monoxide （CO）, an endogenous signaling molecule in animals, also provides potent cytoprotective effects including attenuation of lung lipid peroxidation induced by oxidant in the mouse. Our recent work demonstrated that 0.01 μmol/L hematin （a CO donor） treatment of wheat plants alleviated salt-induced oxidative damage in seedling leaves. In this report, we further discovered that hematin pretreatment （≤ 0.1 μmol/L） could delay wheat leaf chlorophyll loss mediated by further treatment of H202 and paraquat, two reactive oxygen species （ROS） sources, in dose-and even time-dependent manners. Also, compared with the control samples, seedling leaves pretreated with 0.01 or 0.1 μmol/L hematin for 24 h exhibited lower levels of H2O2 and lipid peroxidation, as well as higher contents of chlorophyll and activities of antioxidant enzymes. Such beneficial effects exerted by hematin were mimicked by the pretreatment of antioxidant butylated hydroxytoluene （BHT）, and differentially reversed when CO scavenger hemoglobin （Hb）, or CO specific synthetic inhibitor ZnPPIX was added, respectively. Taken together, the results presented In this paper directly illustrate for the first time that CO is able to strongly protect plants from oxidative damage caused by the overproduction of ROS, and strengthens the evidence that CO is a potent antioxidant in various abiotic and biotic stresses, as similar results have been shown in animal tissues.     

水稻淡黄绿叶色突变体的光氧化特性研究

为了解水稻淡黄绿叶色突变体‘标810S’的光保护机制,在自然强光条件下对突变体‘标810S’及其野生型‘810S’连体剑叶经5mmol/L甲基紫精(MV)处理后的光氧化特性进行了比较研究。结果表明,在MV处理条件下,突变体‘标810S’剑叶净光合速率(Pn)、PSⅡ最大光化学量子产量(Fv/Fm)、PSⅡ实际光化学量子产量(ФPSⅡ)和光化学淬灭(qP)下降幅度明显低于野生型‘810S’,而非光化学淬灭(qN)上升幅度及PSⅠ和PSⅡ活性则明显高于‘810S’;同时,‘标810S’剑叶抗坏血酸(AsA)、还原型谷光甘肽(GSH)含量以及超氧物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)等抗氧化酶活性均明显高于‘810S’,而超氧阴离子(O-·2)产生速率、膜脂过氧化物丙二醛(MDA)含量则明显低于‘810S’。研究认为,在光氧化处理下淡黄绿叶色突变体‘标810S’是通过增加热耗散、提高抗氧化物质含量和保护酶活性、减少超氧阴离子和丙二醛的积累来维持较高的光系统活性和光合能力,从而表现出耐光抑制(光氧化)的生理特性。     

抗氧化系统在热激诱导的玉米幼苗耐热性形成中的作用

玉米幼苗经过42℃热激4h并恢复4h后,显著提高了玉米幼苗在高温处理下的存活率。热激并恢复4h后,不同程度地提高了抗氧化酶系统过氧化氢酶(CAT),超氧化物歧化酶(SOD),谷胱甘肽还原酶(GR),抗坏血酸过氧化物酶(APX)和过氧化物酶(GPX)的活性以及抗氧化剂还原型抗坏血酸(ASA)和谷胱甘肽(GSH)的含量,且经过热激的玉米幼苗在高温处理期间及其后的恢复过程中均能保持相对较高的抗氧化酶活性和抗氧化剂水平,说明保持较高的抗氧化酶活性和抗氧化剂水平是热激诱导的玉米幼苗耐热性形成的生理基础之一。