小叶旱烟(Nicotiana rustica)茎愈伤组织的原生质体再生成完整植株的研究

用纤维素酶成功地从小叶旱烟茎愈伤组织中分离出了大量具有活力的原生质体。在所确定的培养条件下,由原生质体培养出了愈伤组织,并发育成完整植株。同时,对IAA、α-NAA和激动素在原生质体再生成完整植株中的作用进行了研究。     

大麦叶肉原生质体培养中核酸酶活性的研究

在利用原生质体技术来改良谷类作物的工作中,掌握其分离的原生质体再生完整植株的技术是非常重要的一环。由一些禾谷类作物愈伤组织来源的原生质体,已能连续产生细胞分裂,并进而形成愈伤组织或小植株;然而由叶肉来源的原生质体,在培     

美国植物遗传工程取得新进展

据《生物工程新闻》一九八五年五卷二期报道,美国孟山都(Monsanto)公司科学家建立了利用根癌土壤杆菌(Agrobacteriom tumefaciens)的遗传物质直接插入完整植物细胞(而不是原生质体)中的方法,认为用完整细胞比其原生质体有它的优点,因为原生质体再生植株可能遇到再生产的困难,另外,许多植物种不能从原生质体再生植 。     

从胡萝卜愈伤组织分离的原生质体获得再生植株

植物原生质体培养技术广泛地应用于体细胞杂交、遗传物质转移、核及细胞器的移植及其他的研究工作。目前几种植物的原生质体培养已经能够再生成完整植株。我们研究了用自己制备的纤维素酶分离固体培养的胡萝卜愈伤组织原生质体的条件和再生细胞分裂、植株分化的条件。     

从原生质体再生水稻

<正> 据国家农业生物资源研究所宣称,从原生质体已首次再生出水稻植株。该所(农林水产省的一个研究单位)的研究人员分别培养出60种原生质体。其中中,有4种能生根和发芽,有一种可长成10厘米高的完整植株。20种原生质体来自种子细胞,而其它40种是由某些花粉细胞中分离的细胞壁,这些花粉细胞是从单个花粉细胞繁殖来的。     

我国水稻原生质体再生完整植株取得重要突破

水稻细胞成株一直是生物技术中一个难题,国内外生命科学科工作者多年以来试图攻克这一难关,最近中国科学院遗传研究所科学工作者继日本(BN.17/V,85)利用 水稻原生质体再生完整植株取得成功以后终于成功地实现了中国水稻原生质体(去壁的细胞)再生葱缘茁壮的完整植株,这是在我国植物细胞工程研究的一次重要突破,有其重要意义:①通过水稻原生质体成株的事实证明,这项技术路线用于研究其他有经济价     

从龙葵叶肉细胞原生质体再生植株

用自制的纤维素酶从龙葵(Solanum nigrum L.)叶肉细胞制备了大量有活力的原生质体。用悬滴和浅层培养法,龙葵原生质体生长、分裂、形成愈伤组织,并再生成完整的植株。比较了在 NT 培养基中不同肌醇含量对原生质体的影响;每升培养基中加250毫克的肌醇能促进龙葵叶肉原生质体的生长和分裂。     

大白菜无菌苗叶肉原生质体植株再生

商用大白菜叶肉原生质体,经液体培养基浅层培养,再生细胞分裂．并获得愈伤组织。愈伤组织转到分化培养基上诱导分化,已从城青2号大白菜叶肉原生质体得到再生的完整植株。再生细胞的分裂额率与培养基中的激素种类和浓度有关,受原生质体培养浓度的影响。多胺类物质[亚精胺(SPD)]的加入,可促进细胞分裂,井有益于以后植株的再生。通过提高新鲜培养液的pH值(6．5)可使细胞团的褐化得到明显的控制。在植株分化过程中,培养基中低浓度(1．1％)的蔗糖与植株分化有关。     

超甜玉米原生质体培养和植株再生

以商用超甜玉米(SS7700)的单倍性悬浮细胞培养物为材料游离的原生质体,经培养再生成完整植株并移栽成活。用悬浮细胞作为滋养物比对照提高植板率130倍以上。有机附加物丰富的培养基比简单培养基植板率要高。孔径在0.22—8.0μm 的硝酸纤维素或醋酸纤维素滤膜作为支持膜,对原生质体培养都是合适的。和原生质体亲缘关系越近的物种作为滋养细胞的效果越好。在检查过的11植由原生质体再生的植株中,10株为单倍体,1株为二倍体。     

PEG法介导转化诸葛菜下胚轴原生质体获得转基因植株

采用诸葛菜无菌苗的下胚轴组织为材料,分离原生质体,在原生质体培养基中作液体浅层暗培养,植板率为５％,植株再生频率为１００％。作者进而开展了遗传转化研究。为研究ＰＥＧ介导转化诸葛菜原生质体的影响因素,通过瞬间表达,实验了ＰＥＧ法转化子叶原生质体的过程,在此基础上将分离纯化后的原生质体与带ＨＰＴ基因的质粒ＤＮＡ（ｐＢＩ２２２）混合,ＨＰＴ基因作选择标记,ＰＥＧ介导转化;重新收集转化后的原生质体,以５×１０４／ｍｌ的密度在原生质体培养基中作浅层培养;培养１０—１５天后用２５ｍｇ／Ｌ的潮霉素（ｈｙｇｒｏｍｙｃｉｎ）进行筛选,一月后出现少量细胞团,转入含潮霉素５０ｍｇ／Ｌ的扩增培养基扩增愈伤组织,进而转入含５０—１００ｍｇ／Ｌ潮霉素的分化培养基诱导分化成苗,分化率为１００％,转入生根培养基中生根成完整植株。抗性植株再生率为４×１０（－５）。在获得再生转基因植株后,以再生植株叶片为材料,进行Ｓｏｕｔｈｅｒｎｂｌｏｔ分子杂交,证实外源基因已稳定整合到植物基因组中并表达,再生转基因植株频率为１０（－５）。国内外首次转化诸葛菜属植物原生质体获得成功。     

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.