杜仲愈伤组织超低温保存的研究

采用单因子比较、正交设计和均匀设计法,分别考察影响杜仲愈伤组织诱导、生长及其超低温保存的因素。试验表明：Ｂ５＋ＮＡＡ０．５ｍｇ／Ｌ＋６—ＢＡ１ｍｇ／Ｌ有利于意伤组织诱导。ＭＳ＋２．４—Ｄ３ｍｇ／Ｌ＋６—ＢＡ０．５ｍｇ／Ｌ则有利于愈伤组织快速生长。超低温保存的最佳材料是２周龄的愈伤组织。愈伤组织超低温保存的较好冷冻保护剂是１２．５％Ｇｌｙ＋７．５％ＰＥＧ＋２．５ｇ／ＬＬＨ。     

防风愈伤组织的玻璃化法超低温保存及再生

为避免连续继代造成的愈伤组织变异,探索新的种质资源保存方法,对防风愈伤组织进行了超低温冷冻保存及植株再生研究。以关防风3周龄的愈伤组织为材料,单一变量法研究适宜的玻璃化法超低温保存程序。结果显示:(1)防风愈伤组织超低温保存的最佳方案为:4℃条件下于MS+1.0mg/L 6-BA+1.0mg/L NAA+5%DMSO的继代培养基中预培养3d,60%PVS2常温装载20min,100%PVS2于2℃脱水45min后直接投入液氮。(2)防风愈伤组织经超低温保存后的相对存活率最高为79.24%,其中预培养和脱水是实现超低温冻存的关键环节,且1.0mol/L蔗糖的MS溶液洗涤、暗培养14d以上有助于冻后愈伤组织恢复生长。研究表明,玻璃化超低温冻存可以作为防风愈伤组织的保存方法,冻后愈伤可以恢复生长并再生成完整植株。     

草莓愈伤组织超低温贮藏及植株再生研究

本文介绍了草莓愈伤组织的诱导,超低温贮藏及不同解融方法对其细胞存活率和芽分化的影响。     

疣粒野生稻体细胞超低温保藏与原生质体培养体系的确立

疣粒野生稻是原产于我国的 3种野生稻之一 .疣粒野生稻具有优异特性但极难培养 .从疣粒野生稻的幼穗诱导出无再生能力的愈伤组织 ,经过继代培养和超低温保藏后获得了胚性愈伤组织 ,建立了悬浮细胞系 ,分离出原生质体并再生出植株 .人工接种鉴定表明 ,再生植株的强抗病性没有改变 ,但获得了培养力高的特性 .研究结果证明了植物愈伤组织的超低温保藏可能是获得胚性细胞系的一种新途径 .原生质体再生体系的确立是应用原生质体融合技术转移疣粒野生稻有用基因的重要一步 .     

仙客来愈伤组织的超低温保存

为了避免连续继代造成仙客来愈伤组织的变异, 对仙客来愈伤组织进行了超低温冷冻保存研究。以继代后处于对数生长期的愈伤组织为实验材料, 首先在含有不同蔗糖浓度的培养基上预培养不同时间, 转至不同的冰冻保护剂中直接液氮冷冻或-20oC预冷冻2 h, 然后液氮超冷冻保存, 37oC水浴迅速解冻, 并用相应蔗糖浓度的液体培养基洗涤, 以中性红染色测定细胞的存活率, SPSS13.0软件进行统计学分析。结果表明: 预培养基中蔗糖浓度、预培养时间、降温方式、冷冻保护剂等对解冻后材料相对存活率存在不同程度的影响, 筛选出4%蔗糖浓度预培养3 d、9号保护剂、0oC停留30 min后直接冷冻为超低温保存的最佳方案, 通过简单的方法获得了较好的愈伤组织保存效果。     

仙客来愈伤组织的超低温保存

为了避免连续继代造成仙客来愈伤组织的变异, 对仙客来愈伤组织进行了超低温冷冻保存研究。以继代后处于对数生长期的愈伤组织为实验材料, 首先在含有不同蔗糖浓度的培养基上预培养不同时间, 转至不同的冰冻保护剂中直接液氮冷冻或-20oC预冷冻2 h, 然后液氮超冷冻保存, 37oC水浴迅速解冻, 并用相应蔗糖浓度的液体培养基洗涤, 以中性红染色测定细胞的存活率, SPSS13.0软件进行统计学分析。结果表明: 预培养基中蔗糖浓度、预培养时间、降温方式、冷冻保护剂等对解冻后材料相对存活率存在不同程度的影响, 筛选出4%蔗糖浓度预培养3 d、9号保护剂、0oC停留30 min后直接冷冻为超低温保存的最佳方案, 通过简单的方法获得了较好的愈伤组织保存效果。     

玉米愈伤组织对草丁膦的抗性及氨基酸对这种抗性的影响

将玉米（ＺｅａｍａｙｓＬ．）（Ｐ９１０×Ｚ３１）愈伤组织接种于含不同浓度草丁膦及不同氨基酸的Ｎ６培养基上,测定愈伤组织重量增长及ＮＨ＋４积累水平。统计结果表明,当培养基中草丁膦浓度为４ｍｇ／Ｌ时,愈伤组织重量增长最低;浓度为８ｍｇ／Ｌ时,ＮＨ＋４积累水平达最高。综合考虑这两种因素,在培养基上选择转化体的草丁膦浓度以６ｍｇ／Ｌ为宜。在含有草丁膦的选择培养基上,Ｌ精氨酸和Ｌ谷氨酸能通过代谢调节显著降低玉米愈伤组织中的ＮＨ＋４浓度;而Ｌ脯氨酸虽明显促进玉米愈伤组织在选择培养基上的重量增长,但并不降低玉米愈伤组织中的ＮＨ＋４浓度     

荞麦愈伤组织分化与过氧化物酶活性及其同工酶关系的研究

在附加不同外源激素的培养基中,龙山荞的子叶愈伤组织表现出不同的分化状态：（１）不分化;（２）分化根;（３）分化芽;（４）分化全苗。四种愈伤组织的过氧化物酶活性的相对幽会为１：１．４７：５．９５：７．７８,并且过氧化物酶同工酶谱也存在明显差异。酶带４’为分化愈伤组织所特有;酶带２’为未分化和分化愈伤组织所共有;在分化根和未分化愈伤组织中缺少酶带１’;未分化愈伤组织比分化愈伤组织多出酶带３’。     

植物离体培养产生草珊瑚有效成分

报道了以草珊瑚外植体诱导愈伤组织的适宜培养基和各种植物激素在诱导及其生长培养中的调节作用。应用薄层层析（ＴＬＣ）和紫外光鉴定，证明所获得的愈伤组织具有合成与原植物材料相同的黄酮类、异嗪上以啶类、延胡索酸等有机酸的能力。亦通过愈伤组织无性系筛选过程，得到一个增长率和代谢物产量比愈伤组织母系高４倍左右的优良愈伤组织系。     

苦丁茶愈伤组织的诱导与褐变抑制

以叶片为材料,对苦丁茶愈伤组织的诱导,继代培养及褐变调控的研究表明：（１）苦丁茶愈伤组织的诱导及继代培养均以ＭＳ附加ＢＡ ２．０ｍｇＬ＾－１和ＮＡＡ ４．０ｍｇＬ＾－１的培养基效果最好;（２）０．１％的植酸可明显促进愈伤组织生长、抑制褐变,而硫代硫酸钠效果最差;（３）连续培养４０－５０ｄ愈伤组织增长倍数达到最大值;（４）继代２７次以后愈伤组织生长速度开始下降。这些条件为下一步细胞培养生产苦丁茶甙等     

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.