水母雪莲愈伤组织和悬浮培养细胞的抗冻性研究

水母雪莲（Saussurea meduasaMaxim）是典型的高山雪线植物。本文研究了其愈伤组织及悬浮细胞的培养过程,并对其抗寒性做了初步研究。 研究结果表明,水母雪莲愈伤组织和悬浮培养细胞分别可抵抗-6.5 ℃、-7.5 ℃的冰冻低温胁迫。水母雪莲愈伤组织细胞内丰富的蛋白质和淀粉粒多糖构成其较强抗冻能力的物质基础。低温锻炼后,悬浮细胞分泌蛋白中有新的多肽（76,48,27.5,19.5 kD）合成,而33,51 kD两条多肽合成增强。悬浮细胞抗冻能力的提高同蛋白质合成的增强是一致的。     

光照对水母雪莲愈伤组织合成生物碱的影响

以水母雪莲（Saussurea medusa Maxin.)无菌幼苗的根作外植体,诱导获得的愈伤组织为材料,研究光照对生物碱合成的影响。结果表明：尽管在水母雪莲的愈伤组织培养物中,总生物碱的含量比原植株中的含量低,但其组成成分比原植物丰富。并且秋水仙碱的含量也比原植物高,尤其是在光照培养的愈伤组织中秋水仙碱大大增加。     

低温诱导唐古特红景天细胞分泌抗冻蛋白

选择青海高原海拔4000m高山上生长的唐古特红景天为实验材料,以叶片为外植体,在MS+BA₂+NAA_0.2固体培养基上诱导出黄绿色、松脆愈伤组织.愈伤组织细胞在同样成分的液体培养基中培养获得成功.在悬浮培养液中可检测到分泌蛋白的存在.经SDS-聚丙烯酰胺凝胶电泳分析表明,低温锻炼或脱落酸（ABA）诱导后,细胞分泌蛋白的多肽谱带数增加.与此相对应的是,细胞的抗冻能力也明显提高.PAS染色揭示多肽中均含有糖基.通过测定热滞值,确信细胞分泌蛋白是具有抗冻活性的糖蛋白.     

红豆杉细胞培养的研究

从红豆杉（Ｔａｘｕｓｃｈｉｎｅｎｓｉｓ（Ｐｉｌｇ）Ｒｅｈｄ）的嫩茎及针叶诱导的出愈伤组织,对愈伤组织培养及细胞悬浮培养进行了研究,利用ＨＰＬＣ方法测定它们合成紫杉醇的能力,发现了能够提高培养细胞生长速率及紫杉醇含量的一些因子,红豆杉愈伤组织及悬浮培养细胞的生长速率已分别达到０．２５ｇ／Ｌ．ｄ和０．２８ｇ／Ｌ．ｄ。而他们的紫杉醇含量分别是０．００２６％和０．０１２％。     

不同理化因子对雪莲培养细胞中黄酮类形成的影响

研究了不同理化因子对水母雪莲(Saussurea medusa Maxim)愈伤组织生长及黄酮类化合物生物合成的影响。结果表明,有利于细胞生长及黄酮形成的合适温度为25℃。白光对愈伤组织生长无促进作用,但有利于黄酮的形成。培养基中添加1mg／L NAA和O．2mg／L的KT组合对细胞的生长较有促进作用。5％蔗糖和1％葡萄糖的组合有利于细胞的生长和黄酮的形成。用⁶⁰C0-γ射线辐照愈伤组织,在剂量为4000Gy的条件下,获得一个合成黄酮能力高于原愈伤组织70％的细胞系。用高效液相和紫外分光光度法,测定离体培养光照条件下干细胞总黄酮的含量为3．2％,是暗培养的4．4倍。培养温度25℃时干细胞黄酮的含量为2．02％,分别为20℃,35℃时的5倍和3．2倍。     

凹叶厚朴愈伤组织的超低温保存

采用单因子比较和均匀设计法。研究凹叶厚朴愈伤组织超低温的影响因素。结果表明：超低温保存的适宜材料是４周龄的愈伤组织。经４－６℃低温下预培养１２天的愈伤组织抗冻能力最强。     

宁夏枸杞器官发生和体细胞胚胎发生过程中DNA、RNA和蛋白质合成动态的比较研究

宁夏枸杞(Lycium barbarum L.)叶外植体来源的愈伤组织经筛选、繁殖后,将来源相同、状态较为一致的淡黄色愈伤组织转移至O型或E型培养基上,可以诱导出器官发生和体细胞胚胎发生。利用该体系,对两条离体再生途径进行了比较研究。结果表明:(1)在拟分生组织和胚性细胞形成之前,RNA合成首先被激活,随后DNA、蛋白质合成加速;而球形胚形成期间,先是DNA合成的加快,接着RNA、蛋白质的合成高峰出现,在不定芽形成期间却正好相反;(2)可溶性蛋白组分发生规律性变化;器官发生和体细胞胚胎发生的启动阶段都有-153.6kD多肽出现,一些多肽分子在分化早期逐渐消失,而随芽原基或球形胚的形成又重新合成;与形态发生相对应,两种再生体系都有作为各自分子标记的特异多肽(84.9kD、46.3kD和44kD、36.2kD)的表达。此外,还对两种离体再生体系之间的关系和发生机制进行了讨论。     

文摘

030 0 2 9搅拌式生物反应器悬浮培养水母雪莲细胞的研究〔中〕/黄艳… //生物工程学报 .- 2 0 0 1,17(5 ) .- 5 6 1～ 5 6 5应用 2L通气搅拌式生物反应器一步批式培养水母雪莲细胞。采用倾斜式搅拌桨代替透平桨 ,研究了搅拌转速、通气量和接种量对细胞生长和黄酮合成的影响 ,发现在 75r/min、70 0～ 10 0 0L/min和 4 .0～ 5 .0gDCW /L接种量下细胞生长和黄酮合成比较好。经过 12d培养细胞干重达 13.8gDCW /L ,黄酮产量 4 16mg/L ,黄酮含量占细胞干重的 3.0 %。水母雪莲细胞生长及黄酮合成的进程表明 ,黄酮积累与细胞生长呈正相关。对细…     

新疆雪莲DFR基因的分离及同源遗传转化

二氢黄酮醇4-还原酶（dihydroflavonol 4-reductase,DFR）是植物重要的次生代谢产物花青素生物合成途径中的关键酶。运用RT-PCR和RACE技术从新疆雪莲(Saussurea involucrata Kar.et Kir.)中克隆得到DFR基因(GenBank登录号为JN092126)。DFR基因的cDNA全长序列含有1个1 029 bp的开放阅读框(ORF),编码343个氨基酸,该基因推断的蛋白与水母雪莲DFR基因推断的蛋白高度同源,相似性达到92%;以不同物种中DFR氨基酸序列进行比对分析,推断的蛋白含有与NADPH特异结合的结构域。将该基因运用农杆菌介导的叶片转化法进行同源转化,将含有转DFR基因的愈伤组织进行悬浮培养,紫外分光光度法测定愈伤组织的总黄酮含量,结果表明转基因愈伤组织的总黄酮含量明显高于非转基因愈伤组织的含量。该研究为提高新疆雪莲药用化学成分黄酮类物质及实现新疆雪莲花青素的人工生物合成的研究奠定基础,对解决天山雪莲资源匮乏提供参考。     

水母雪莲细胞悬浮培养合成黄酮及抗氧化活性

对水母雪莲细胞悬浮培养过程中细胞生长、黄酮积累和底物消耗的动力学过程进行了研究.经15 d液体培养可获得最大生物量干重和黄酮产量分别为17.2 g·L-1和607.8 mg·L-1,通过调控基本培养基种类和有机添加物可提高雪莲细胞的生长和黄酮积累.获得的水母雪莲细胞培养物具有明显的抗氧化活性,其抗氧化活性与雪莲细胞中的黄酮含量相关.     

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.