模拟微重力条件下几种植物的过氧化物酶同工酶谱分析

对模拟微重力条件下的人参果、马铃著和草莓处理后进行了过氧化物酮同工酶谱分析实验。结果表明,在模拟微重力条件下过氧化物同工酶的活性明显增强。     

模拟微重力对拟南芥幼苗的影响

对正常条件和模拟微重力条件下拟南芥幼苗的生长状况进行了研究,发现拟南芥幼苗的生长发育、生理生化特性、酶活性等均发生一系列的变化.并利用qRT-PCR技术深入研究了经模拟微重力处理的幼苗过氧化物酶的基因表达量的变化.这些结果为植物在受控生态生保系统中的生长提供了试验支持.     

模拟微重力诱导PC12细胞衰老的初步探讨

目的：构建模拟微重力条件下PC12细胞的培养体系,探讨模拟微重力对PC12细胞衰老的影响。方法：用Cytodex-3型微载体作为PC12细胞的贴附载体,旋转细胞培养系统所提供10-2g的微重力环境进行模拟微重力条件下的细胞培养。在倒置显微镜下观察PC12细胞的生长情况;用扫描电镜观察PC12细胞超微结构的变化;衰老相关β半乳糖苷酶（SA-β-gal）特异性染色对衰老的PC12细胞进行评估。结果：光镜下模拟微重力培养的PC12细胞表现出类衰老细胞的形态,扫描电子显微镜下观察发现其微绒毛增多。SA-β-gal染色的结果显示在模拟微重力的作用下,PC12细胞SA-β-gal的活性升高。结论：模拟微重力可以引起PC12细胞衰老样的形态变化,以及SA-β-gal的活性升高。     

模拟微重力诱导PC12 细胞衰老的初步探讨

目的:构建模拟微重力条件下PC12细胞的培养体系,探讨模拟微重力对PC12细胞衰老的影响。方法:用Cytodex-3型微载体作为PC12细胞的贴附载体,旋转细胞培养系统所提供10-2g的微重力环境进行模拟微重力条件下的细胞培养。在倒置显微镜下观察PC12细胞的生长情况;用扫描电镜观察PC12细胞超微结构的变化;衰老相关β半乳糖苷酶(SA-β-gal)特异性染色对衰老的PC12细胞进行评估。结果:光镜下模拟微重力培养的PC12细胞表现出类衰老细胞的形态,扫描电子显微镜下观察发现其微绒毛增多。SA-β-gal染色的结果显示在模拟微重力的作用下,PC12细胞SA-β-gal的活性升高。结论:模拟微重力可以引起PC12细胞衰老样的形态变化,以及SA-β-gal的活性升高。     

二萜醌类成分与过氧化物酶同工酶关系的初步研究

本文以聚丙酰胺凝胶柱电泳,分析了唇形科18种植物的过氧化物酶同工酶。实验表明含二萜醌类成分的种,它们的过氧化物酶同工酶的酶谱在中部偏正极处明显。二萜醌类化合物的含量与其过氧化物酶同工酶的酶谱表现常一致。含挥发油成分的种在上述条件下,过氧化物酶同工酶几乎不出现谱带。     

模拟微重力对拟南芥幼苗的生物学效应

对正常条件和模拟微重力条件下生长的拟南芥幼苗进行比较试验,结果表明模拟微重力会产生如下影响:(1)影响拟南芥幼苗的生长发育;(2)影响拟南芥光合特性;(3)影响拟南芥的生理特性;(4)影响拟南芥植株的钙离子分布。此外,运用基因芯片技术探讨模拟微重力对拟南芥基因表达的影响。     

谷子耐盐系的几种同工酶的变化及外源ABA对它们的影响

对谷子细胞变异系的过氧化物酶,细胞色素氧化酶和脂酶同工酶的分析表明：耐盐系在无盐胁迫条件下过氧化物酶同工酶的总酶活性高于对照系,其各同工酶带的强度也与对照有明显差异;在ＮａＣｌ迫条件焉耐盐系中个别原有的酶带消失。细胞色素氧化活性与过氧化物酶同工酶的活性变化情况类似,均与对照有明显差异。     

在不同营养条件下铜绿微囊藻对模拟微重力胁迫的响应

通过测定在不同重力水平和营养条件下培养的铜绿微囊藻(Microcystis aeruginosa)的各项生理生化指标,研究了培养基的营养物质浓度对微囊藻细胞响应模拟微重力胁迫的影响。结果表明,在正常浓度的BG-11(富营养)和营养盐浓度减为1/10的BG-11(贫营养)培养基中培养的微囊藻对模拟微重力胁迫都很敏感,培养2d后多项生理生化指标显著改变;但是在富营养和贫营养条件下,模拟微重力的作用效果是截然不同的。对培养在BG-11中的微囊藻细胞来说,模拟微重力抑制其生长和光合活性,导致细胞内色素(叶绿素a和类胡萝卜素)、蛋白(藻蓝蛋白和可溶性蛋白)和毒素含量显著升高,向外分泌的毒素含量降低;而对培养在1/10BG-11中的藻细胞来说,模拟微重力促进其生长和光合活性,导致细胞内色素、蛋白和毒素含量降低,并使得毒素分泌增强。模拟微重力或营养限制单独作用所造成的影响相似,且后者的作用效果强于前者。当二者同时存在时,模拟微重力可以部分抵消营养限制对微囊藻生长和代谢的影响,这可能是由于模拟微重力下藻细胞的生长受到抑制而导致营养需求降低,也可能是由于模拟微重力提高了藻细胞利用营养物质的效率。总之,微囊藻对模拟微重力胁迫的响应与培养基的营养条件有关。     

槲皮素对模拟微重力条件下体外培养大鼠心肌细胞骨架的影响

采用细胞免疫双荧光染色观察离体培养的大鼠心肌细胞微丝和微管分布 ,探讨模拟微重力条件下槲皮素对心肌细胞骨架分布的影响。结果表明 :模拟微重力条件下心肌细胞微丝、微管在近胞核区的分布增多 ;模拟微重力处理的同时加入槲皮素 ,则使近胞核处微丝、微管分布明显减少 ,微丝束的粗细与对照组无异。提示模拟微重力可显著影响心肌细胞微丝、微管的分布 ,槲皮素可对抗该效应而发挥其心肌细胞保护作用 [动物学报49(1) :98～ 10 3 ,2 0 0 3]。     

模拟微重力效应对心肌细胞一氧化氮水平的影响及其相关机制的研究

空间微重力导致的心肌收缩功能下降是航天医学的重要问题, 其发生机制尚不清楚. 采用电子自旋共振(ESR)、免疫细胞化学和核酸原位杂交等技术研究了模拟微重力效应对心肌细胞一氧化氮(NO)水平、诱导型一氧化氮合成酶(iNOS)表达的影响及其调控的信号转导途径, 以探讨模拟微重力影响心肌细胞收缩功能的可能机制. 结果表明, 模拟微重力导致心肌细胞NO水平增高, iNOS蛋白及其mRNA表达上调; 非选择性的蛋白激酶抑制剂staurosporine和选择性的蛋白激酶C ( PKC )抑制剂calphostin C均可显著抑制模拟微重力下心肌细胞NO水平增高, 说明模拟微重力对iNOS表达的调节至少是部分地依赖于PKC途径. 结果提示, 心肌细胞NO途径对模拟微重力条件敏感, 该途径可能在模拟微重力影响心肌细胞收缩功能的机制中发挥重要作用.     

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.