巨噬细胞、内皮细胞对高密度脂蛋白的氧化修饰

为了探讨高密度脂蛋白 (HDL)在体内发生氧化修饰的部位及机制 ,分别观察了培养人动脉平滑肌细胞 (SMC)、动脉内皮细胞 (EC)及巨噬细胞 (MΦ)与HDL共同温育过程中 ,HDL的琼脂糖电泳相对迁移率 (REM)、硫代巴比妥酸反应物质 (TBARS)以及溶血卵磷脂 卵磷脂 (LPC PC)值等氧化指标的变化 .结果发现 ,HDL与 3种细胞温育 12h时 ,HDL几乎不发生氧化修饰 ,而HDL与MΦ和EC温育 2 4h后 ,其REM、TBARS、LPC PC值均显著上升 (p <0 0 1) ;而HDL与SMC温育后 ,其REM、TBARS值无显著改变 ,LPC PC值增加 (p <0 0 1) .结果提示 ,活体内HDL可能主要在动脉壁的内皮细胞及巨噬细胞的作用下发生氧化修饰     

氧化修饰高密度脂蛋白的研究进展

血浆高密度脂蛋白(HDL)与低密度脂蛋白(LDL)一样可以在体内外发生氧化修饰,引起其理化性质发生一系列的改变,如多不饱和脂肪酸过氧化,卵磷脂水解,蛋白质发生聚合或分解等.活体内HDL可能在动脉壁巨噬细胞、内皮细胞及中性粒细胞、单核细胞的作用下发生氧化修饰.氧化修饰HDL可能通过清道夫受体途径代谢.氧化修饰HDL产生多种致动脉粥样硬化作用.维生素E、C的摄入可能有助于防止脂蛋白的氧化.     

动脉壁细胞氧化修饰极低密度脂蛋白

将正常极低密度脂蛋白（ｎ－ＶＬＤＬ）分别与动脉壁的三种主要细胞：巨噬细胞（Ｍφ）、内皮细胞（ＥＣ）、平滑肌细胞（ＳＭＣ）温育２４小时后,ＶＬＤＬ的ＴＢＡＴＳ值明显增高,琼脂糖电泳速度加快,溶血卵磷脂与卵磷脂（ＰＣ）的比值明显升高,载脂蛋白的Ｂ１００（ａｐｏＢ１００）发生降解,未见集中的降解区带,ａｐｏ遥相对含量在各组无明显变化,加入抗氧化剂２,６－叔丁基甲苯能抑制上述变化,这些结果表明：动脉壁的三     

载脂蛋白AI结构与功能研究进展

载脂蛋白AI（apoAI)是高密度脂蛋白（HDL）中主要的蛋白质,它是细胞胆固醇逆向转运（RCT）的特殊重要因素,ApoAI能与磷脂,多种血浆因子及细胞膜受体结合,可以激活卵磷脂胆固醇酰基转移酶（LCAT）,起着促进细胞内胆固醇的移出,酯化,转移,以及调节HDL代谢的作用。ApoAI在各种HDL亚类中其空间结构有较大差异。这与HDL成熟过程及运载胆固醇等生理功能密切相关。     

牛血清白蛋白对超氧化物歧化酶的化学修饰

目的：通过化学修饰提高超氧化歧化酶（SOD）的稳定性,考察金属离子在不同浓度下对SOD活性的影响。方法：用戊二醛作为交联剂,用牛血清白蛋白（BSA）将牛红细胞超氧化物歧化酶进行化学修饰,得到SOD的修饰酶。对比研究三种SOD：修饰酶,混合酶及天然酶的理化性质。结果：修饰酶等电点降低,对温度、pH的稳定性较天然酶有很大提高,对胰蛋白酶和胃蛋白酶也表现出很强的耐水解性。二价离子Mg^2 、Mn^2 对天种SOD活力均有不同程度的抵制作用,Ca^2 、Zn^2 、Cu^2 对修饰酶活力有激活作用,一价离子K^ 对三种OSD活力均无明显影响.结论:修饰酶较天然酶的稳定性有很大的提高,加入Ca^2 、Zn^2 、Cu^2 可提高修饰酶的活力。     

氧化修饰在调控细胞凋亡信号转导中的作用

氧化修饰是细胞内的活性氧诱导生物大分子发生氧化反应引起的结构及构象改变,发挥调控信号转导和对应激作出反应的功能。氧化修饰发生在凋亡信号转导中的多个生物大分子,包括凋亡相关蛋白质的氧化,如caspase-9、线粒体通透性转变孔及电压依赖的阴离子通道(voltagedependent anion channel,VDAC),同时也包括膜磷脂的氧化修饰,如磷脂酰丝氨酸及线粒体特异的心磷脂。氧化修饰作用也涉及凋亡诱导因子、促凋亡的凋亡信号调控激酶1(apoptosis signalregulatin gkinasel,ASK1)信号转导途径及抗凋亡的转录因子NF—kB的激活和活性。所以氧化修饰可能是调控凋亡信号转导机制中除磷酸化、泛素化外的另一个新的分子机制。     

Cu2+作用下辣椒膜脂过氧化及倍半萜环化酶基因转录

分析了在CuCl2作用下辣椒叶片倍半萜环化酶活性,倍半萜环化酶mRNA表达,细胞GSH和GSSG代谢及膜脂过氧化,结果表明,Cu^2 能诱导辣椒叶片表达倍半萜环化酶活性,酶活性的表达与相应的基因转录有关,辣椒叶片在CuCl2作用下合成了含－SH的螯合肽,相应地GSH含量下降,GSSG的含量有所上升,细胞膜过氧化作用加剧,推测细胞膜脂过氧化产物或GSH氧化产物可能参与了CuCl2诱导辣椒倍半萜环化酶基因表达的信号传递作用。     

芦丁和槲皮素对低密度脂蛋白氧化修饰的抑制作用

以低密度脂蛋白（ＬＤＬ）氧化修饰为模型和以硫代巴比妥酸反应物质（ＴＢＡＳ）生成量以及ＬＤＬ的α－Ｔｏｃｏｐｈｅｒｏｌ和荧光物质含量为指标,以时间效应和浓度效应说明槲皮素和芦丁能明显地抑制Ｃａ＾２＋诱导的ＬＤＬ氧化修饰但其抗氧化修饰的程度无明显差异。它们对已受到Ｃｕ＾２＋氧化修饰的ＬＤＬ的过氧化无明显地终止作用。     

组蛋白去乙酰化酶抑制剂诱导肿瘤细胞凋亡的机制

组蛋白去乙酰化酶抑制剂（HDACi）是一类新的化疗药物,能够有效抑制组蛋白去乙酰化酶的活性,促进组蛋白及非组蛋白的乙酰化修饰,在转录和翻译后修饰水平调控肿瘤靶蛋白及凋亡相关蛋白的表达和降解,活化凋亡信号通路,诱导肿瘤细胞凋亡。HDACi抑制抗氧化蛋白的表达,提高细胞内活性氧的水平,引起细胞的氧化损伤。因此,氧化损伤诱导的细胞凋亡也是HDACi杀伤肿瘤细胞的重要机制。HDACi诱导细胞凋亡机制的发现将进一步促进HDACi在临床治疗中的应用。     

牛血清白蛋白对Cu^2＋与δ-MnO2间吸附平衡性质的影响

研究了溶液中牛血清白蛋白（BSA）的存在对Cu^2＋与δ-MnO2间吸附平衡性质的影响,旨在增进人们对Cu^2＋环境化学行为的认识。结果表明：BSA存在下,Cu^2＋在δ-MnO2表面的吸附率-pH曲线呈典型的“S”形,加入BSA使Cu^2＋的吸附突跃向高pH方向移动,影响程度与BSA的加入方式有关,其次序为Ⅳ（先加BSA后加Cu^2＋）〉Ⅲ（Cu^2＋和BSA同时加）≈Ⅱ（（先加Cu^2＋后加BSA）;BSA存在下,Cu^2＋的等温吸附线遵循Langmuir等温吸附方程,Cu^2＋的饱和吸附量随BSA浓度的增大而减小,并随BSA的加入方式而改变,其次序为I（不加BSA）〉Ⅱ≈Ⅲ〉Ⅳ;Cu^2＋在δ-MnO2上的饱和吸附量随温度的升高而增大。在pH=3．0条件下,Cu^2＋在δ-MnO2上的吸附是完全可逆的,但pH=5．0的条件下,吸附是不可逆的,BSA对Cu^2＋的吸附可逆性没有影响。     

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.