烟草属花粉—叶肉原生质体的融合及杂种植株再生

用饥饿预处理分离烟草（Ｎｉｃｏｔｉａｎａ ｔａｂａｃｕｍ Ｌ．）品系Ｎ３６４ Ｋｍ ＋ 二核早中期的花粉原生质体,用ＰＥＧ－高钙高ｐＨ 法诱导其与黄花烟草（Ｎ．ｒｕｓｔｉｃａ Ｌ．）叶肉原生质体融合。通过抗性筛选再生的４ 株小植株,经过氧化物酶同工酶、根尖染色体计数鉴定均为配子－体细胞三倍体杂种。未经筛选处理再生的２１株小植株,经鉴定有６ 株为配子－体细胞杂种。     

芸苔属花粉—下胚轴原生质体融合再生杂种小植株

从青菜（Ｂｒａｓｓｉｃａ ｃｈｉｎｅｎｓｉｓＬ．）单胞中后期至二胞早期花粉分离出原生质体,用聚乙二醇法诱导其与甘蓝型油菜（Ｂ．ｎａｐｕｓＬ．）下胚轴原生质体融合。通过控制双亲原生质体的数量与比率,提高了异源融合率。融合体在离体条件下发生细胞分裂,形成愈伤组织,再生了小植株。染色体计数与酯酶同工酶酶谱分析初步证明获得了１ 株异源三倍体,２ 株异源四倍体。这是以游离花粉时期的原生质体与体细胞原生质体融合,取得“配子－体细胞杂交”成功的首次报道     

粉兰烟草原生质体再生植株

原生质体培养成再生植株是植物休细胞杂 交的关键环节。烟草是原生质体培养和体细胞 杂交的常用材料。烟草属的几个种已能成功地 由原生质体培养成再生植株。野生的粉兰烟草 (N. glazsca)由于具有染色体数目（2n一24）比 普通烟草（2n=48）少的优点,并已成功地被 用车体细胞杂交的亲木之一^[3,4]。本文介绍粉兰 烟草从原生质体游离到植株再生的实验结果。     

脐橙与柠檬种间细胞电融合再生杂种植株

‘纽荷尔’脐橙（Ｃｉｔｒｕｓｓｉｎｅｎｓｉｓ（Ｌ．）Ｏｓｂｅｃｋ）胚性细胞悬浮原生质体与‘尤力克’柠檬（Ｃｉｔｒｕｓｌｉｍｏｎ（Ｌ．）Ｂｕｒｍ．ｆ）叶肉原生质体经电场诱导融合,培养８个月,首批再生了１棵植株,形态学观察,染色体计数及ＲＡＰＤ分析证明异源四倍体体细胞杂种,该杂种的获得为三倍体无籽柠檬品种培育提供了杂交亲本。     

烟草试管

几德明等闭曾用嫁接方法获得茄子品种间 无忆绮扮种,Car'.son[61首次用原生质体融合方法 获得粉蓝烟草与郎氏烟草种间体细胞杂种。我 们试rw一种简易获得体细胞杂种（即无性杂种） 方法,即将不同品种烟草茎段进行无菌操作嫁 接,然后取嫁接愈合具有两种组织的茎段离体 培养再生植株,从中获得了具有两亲本特性的 无忆杂种再生植株。我们暂称此方法为“植物 试管无性杂交”。     

普通烟草和黄花烟草及体细胞杂种过氧化物酶同工酶等电聚焦电泳

日本学者长尾照义(1978)用原生质体融合获得普通烟草与黄花烟草的体细胞杂种植株。1980年陈家玉等在国内首先获得普通烟草(Copus Yeusuku No.4)和黄花烟草(Yellow Flower)的体细胞杂种植株。之后,中国农科院烟草所(1981)也得到相同的结果。陈家玉等(1983)对上述杂种进行了形态学、细胞学和同工酶的分析并取得一定的结果。Dlineee等(1975)分析比较了用等电聚焦技术分离的过氧     

普通烟草和粉蓝烟草体细胞杂种植株后代的育性研究

普通烟草(Nicotiana.tabacum)和粉蓝烟草（N.glauca）叶肉原生质体融合获得种间体细胞杂种植株,其当代育性很低,但株系间稍有差异。杂种植株自交系（SC）随着自交世代的增加,染色体数目变化不大,正常花粉粒的比率增加,育性提高。体细胞杂种植株的回交系(BC)随着回交世代的递增,染色体数目减少,直至接近回交亲本的染色体数,育性趋向正常。高度雄性不育的植株染色体数目稳定,回交仍保持高度的不育。其育性低的主要原因之一是雄性器官退化。     

对粉蓝烟草与矮牵牛体细胞杂种植株的进一步观察

以亲本为对照,观察了粉蓝烟草和矮牵牛的体细胞杂种植株的叶片、气孔和花粉,发现杂种植株的叶片形态及其气孔大小、分布密度都与双亲有显著的差异。同时发现了杂种植株花粉的不育性。进一步证实了我们用原生质体融合的方法得到的植株是远缘杂种植株。     

LpDH活性作为一种遗传标记在体细胞融合中的转移

用具有LpDH活性,但不能分化植株的烟草冠瘿瘤B 6 S 3为亲本的原生质体,和与之有相反特点的正常烟草xanthi品科叶肉原生质体间融合,由融合处理的原生质体形成了愈伤组织并再生了植株。对56株叶片的LpDH活性电脉分析表明,有75％植株含有不同程度的LpDH活性,即能合成章鱼碱。随植株发育成长,一些植株的LpDH活性有减弱或丢失现象。但叶片形态具有双亲部分特征,表明烟草冠瘿瘤的LpDHT活性标记可通过原生质体融合转移 到烟草xanthi细胞中。     

单个原生质体融合系中变异体的不断形成

亲缘品种间原生质体的融合可产生有用的体细胞杂种植株。然而,远缘品种间原生质体的融合常常导致遗传不亲和性,这可能引起亲本之一染色体的快速消失。日本京都大学和京都医科大学的T.Endo等人发现,单个族间融合产物产生的愈伤组织系可能是连续遗传不稳定性的一个来源。他们分离出了由Duboisia hopwoodii细胞悬浮培养原生质体与烟草叶肉原生质体之间融合产生的单个杂种细胞。从融合产物长出了愈伤组织,从这些愈伤组织产生了10个     

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.