超氧阴离子自由基对大鼠脑皮层神经细胞的损伤作用

为了探讨超氧阴离子自由基对神经细胞的影响,以产生超氧阴离子自由基系统（XO/X）作用于原代培养的新生大鼠大脑皮层神经元,分析神经细胞的生长状态、蛋白质被氧化修饰的程度、脂质过氧化程度、核DNA损伤程度、亚细胞结构变化以及Cu/ZnSOD基因表达等变化。结果显示：超氧阴离子自由基可使神经细胞的生长状态不佳,ATP酶活性降低为4.223μmol/(mg.min^-1)(Pr)。细胞总羰基含量增加为295.40μmol/g湿重,LPO含量增加为4.87mol/g(Pr),膜脂流动性下降（P值为0.398),核DNA单链断裂增加（DNA在SCG中的迁移率为7.35mm),亚细胞结构变化（线粒体肿胀和变性等）以及SOD基因表达增强（SOD含量、SOD活性和SODmRNA丰度均增加）。结果说明超氧阴离子自由基可损伤神经细胞的蛋白质、核酸、脂质和亚细胞结构。     

植物超氧化物歧化酶（SOD）的研究进展

超氧化物歧化酶(superoxide dismutase,SOD)在需氧原核生物和真核生物中广泛存在,是活性氧清除系统中第一个发挥作用的抗氧化酶。植物正常代谢过程和在各种环境胁迫下均能产生活性氧和自由基,活性氧和自由基的积累引起细胞结构和功能的破坏。SOD岐化超氧物阴离子自由基生成过氧化氢和分子氧,在保护细胞免受氧化损伤过程中具有十分重要的作用。本文综述了SOD的功能、在细胞中的分布、表达调控和与植物抗逆性的关系。 Abstract:Superoxide Dismutases (SODs) are ubiquitously expressed antioxidant enzyme in aerobic organisms and catalyze dismutation of superoxide anion to hydrogen and molecular oxygen,the first step in active oxygen-scavenging systems.SODs play a central role in protecting cells against the toxic effects of reactive oxygen species generated during normal cellular metabolic activity or as a result of various environmental stresses.This paper reviews the expression and regulation of Sod genes and their functional role(s) during development and in response to stresses.     

超氧化物岐化酶在医学领域的研究现状

超氧化物歧化酶(SOD)是生物体内清除超氧阴离子自由基(O2-.)的一种重要金属酶,具有重要的生理功能,在医药、食品等方面有广泛的应用前景,是目前医学、分子生物学领域研究的热点之一。现对SOD的分类、分布、结构、性质、在相关疾病中的研究进展、临床应用等方面做一综述。     

红果参多糖的提取纯化及抗氧化活性研究

利用超声波辅助水提醇沉法提取并纯化红果参多糖.以抗坏血酸(VC)作参照物,考察了红果参多糖对羟基自由基、超氧阴离子自由基、亚硝基的清除效果及对油脂的抗氧化性能.结果表明:红果参多糖能很好的清除羟基自由基和超氧阴离子自由基,其清除能力与多糖浓度呈正相关性,对油脂的氧化有明显的抑制作用,对亚硝基的清除效果不明显.     

两株乳酸杆菌SY13和LJJ对活性氧的耐受性

【目的】从传统发酵乳制品中筛选具有抗氧化能力的乳酸菌菌株并对其抗氧化特性进行评价。【方法】分别利用乳酸杆菌SY13和LJJ完整细胞和无细胞提取物对亚油酸过氧化的抑制效果,对DPPH自由基、羟自由基、超氧阴离子自由基清除能力,对过氧化氢的耐受性以及对亚铁离子的螯合能力和还原活性进行了研究。【结果】结果表明,SY13和LJJ对亚油酸过氧化的最大抑制率分别达到了62.95%和66.16%;两菌株的无细胞提取物清除超氧阴离子和羟自由基的的效果较好,LJJ完整细胞对超氧阴离子和羟自由基没有清除能力;SY13和LJJ对DPPH自由基的清除能力及对亚铁离子的螯合能力都是完整细胞优于无细胞提取物,还原活性分别相当于305 μmol/L和294 μmol/L的L-cysteine。【结论】以上指标测定的结果说明,这两株乳酸杆菌具有较好的抗氧化能力,具有潜在的应用价值。     

灵芝液体发酵清除自由基活性产物发酵条件的优化

以红灵芝(Ganoderma.lucidum)为实验菌株,对其液体发酵活性产物清除自由基的发酵条件进行了研究。实验考察了培养基成分对灵芝液体发酵所产生的有效产物清除自由基能力的影响。结果表明,葡萄糖、酵母粉分别为灵芝发酵活性产物清除自由基效果较合适的碳源、氮源,最佳质量浓度分别为40 g.L-1和3 g.L-1,清除自由基的能力分别为55.7%、40.8%和66.5%、50.6%;铁离子对灵芝发酵产物清除超氧阴离子具有明显的效果,适宜质量分数为70×10-6;清除超氧阴离子的能力为54.6%,而硒离子对灵芝发酵产物抑制羟自由基有明显的促进作用,最适的质量分数为90×10-6清除羟自由基的能力为67.7%。油酸能促进灵芝发酵产物的清除超氧阴离子和羟自由基的能力,适宜的质量分数为0.1%,清除两种自由基的能力分别为:73.7%,53%。     

资木瓜总黄酮的体内外抗氧化活性研究

采用70%乙醇回流提取,大孔吸附树脂纯化得到资木瓜总黄酮,进一步研究其体内外抗氧化活性。检测资木瓜对Fe3+的还原力,分析资木瓜对羟自由基、DPPH·自由基以及超氧阴离子自由基的清除能力,检测对LPS诱导的氧化应激小鼠模型血液中SOD和MDA的影响。结果发现资木瓜总黄酮具有良好的还原能力,对·OH和DPPH·自由基的最大清除率分别是97.8%、69.8%,但对超氧阴离子的清除率较低仅为38.3%;在体内实验中资木瓜能增加小鼠血清中SOD活性、降低MDA浓度。说明资木瓜总黄酮通过直接清除自由基、增加机体抗氧化酶SOD的活性、减少脂质过氧化物的生成,产生抗氧化活性。     

黄伞胞外多糖抗自由基作用的研究

目的:以乙醇沉淀的黄伞发酵浓缩液得到的胞外多糖为研究对象,检验其对自由基的清除作用。方法:采用电子顺磁共振(EPR)波谱仪检测黄伞胞外多糖清除羟自由基OH.和超氧阴离子自由基O2-.的作用。结果:在样品浓度均为100mg/mL的条件下,利用Fenton反应体系,黄伞胞外多糖对羟自由基OH.的清除率仅为38.5%;而利用次黄嘌呤-黄嘌呤氧化酶体系,黄伞胞外多糖对超氧阴离子自由基O2-.的清除率可达到80.6%。结论:黄伞胞外多糖在体外对自由基有一定的清除作用且其对超氧阴离子自由基O2-.的清除作用明显优于对羟自由基OH.的清除作用。     

牛奶子树不同部位多糖抗氧化活性比较研究

从牛奶子(Elaeagnus umbellata Thunb.)的叶片、枝条、种子中提取多糖,并研究其抗氧化活性.采用热水提取、Savage法除蛋白、80％乙醇沉淀得其粗多糖.以Vc为对照,用番红花红光度法测定其对羟基自由基的清除作用;用邻苯三酚自氧化法测定其对超氧阴离子的清除作用;用Fe3+还原力法测定其还原能力.结果表明:3个部位所含多糖对羟基自由基、超氧阴离子自由基都可起到有效的清除或抑制作用,其中对羟基自由基清除活性依次为:种子＞叶片＞枝条＞Vc,对超氧阴离子自由基清除活性依次为:种子＞Vc＞叶片＞枝条,3个部位所含多糖都有还原性,但效果都不如硫脲.     

超氧阴离子的产生及其在植物体内作用的研究

超氧阴离子自由基不仅是生物体内重要的自由基之一,也是所有活性氧自由基的前体。近年来许多文献报道生物体的一些重大疾病与超氧阴离子自由基关系密切,因此对超氧阴离子的研究具有非常重要的意义。本文综述了有关超氧阴离子自由基在生物体内及体外的产生、超氧阴离子对生物体的作用、超氧阴离子的检测方法、重点总结了超氧阴离子的产生及其在植物体内的作用。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.