烟草脱外壁花粉的电激基因转移

以 β-葡糖苷酸酶 GUS 基因作为报告基因 ,通过瞬间表达的检测 ,比较了烟草 Nicotianatabacum L . 脱外壁花粉、未萌发与萌发花粉的电激导入效果 ,探讨了不同电激条件及启动子对外源基因瞬间表达的影响 .结果表明 :当脉冲时间常数为 13 ms时 ,导致脱外壁花粉和萌发花粉生活力下降约50 %的电场强度分别为 750 V/ cm和 12 50 V/ cm,在此条件下电激 ,二者的导入效果最好 .脱外壁花粉的GUS基因表达水平约为萌发花粉的 5倍、花粉粒的 30倍 .玉米花粉特异启动子 Zm13- 2 60 能启动 GUS基因在脱外壁花粉和萌发花粉中高效表达 ,而 Ca MV 35S的启动活性很低     

细胞分裂素基因（T—cyt）启动子驱动下的GUS基因在烟草和马铃薯中的表达

构建了来自根癌农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍ ｔｕｍ ｅｆａｃｉｅｎｓ） Ｔ－ＤＮＡ 的细胞分裂素基因（Ｔ－ｃｙｔ）启动子驱动下的ＧＵＳ基因的表达质粒,并用以转化烟草（Ｎｉｃｏｔｉａｎａ ｔａｂａｃｕｍ ｃｖ． Ｗ ３８）和马铃薯（Ｓｏｌａｎｕｍ ｔｕｂｅｒｏ－ｓｕｍ Ｌ． ｃｖ． Ｄｅｓｉｒｅｅ）,研究其在转基因植物中表达的定位。结果表明,Ｔ－ｃｙｔ启动子在转基因植株的根、茎、叶、块茎和萌发的种子中均可表达。其中在茎和块茎中的表达是不均一的：在维管束部分表达较强,在侧芽或叶柄的生长点及块茎的芽生长点表达活性较高。此外,在培养基中加入０．１ ｍ ｇ／ＬＢＡＰ,转基因烟草茎中ＧＵＳ基因的表达活性增强,而对ＮＡＡ 没有明显的反应。看来某些外源植物激素对Ｔ－ｃｙｔ启动子的活性有一定的诱导作用     

小麦中外源基因瞬间表达调控研究及兔防御素（NP—1）基因的转化

将不同５上游调控序列驱动下的ＧＵＳ基因用基因枪法导入小麦幼胚和胚性愈伤组织,通过组织化学分析法和荧光分析法对ＧＵＳ基因的表达进行定量检测,比较了几种烟草花叶病毒（ＴＭＶ）Ω增强子序列对小麦中外源基因瞬间表达的调控作用;然后将其中效率最高的玉米Ｕｂｉｌ启动子与兔防御素（ＮＰ－１）连接起来,并加上Ｎｏｓ终止子,构民ＮＰ－１基因小麦表达载体,并转化小麦幼胚,经ＰＣＲ－Ｓｕｔｈｅｒｎ ｂｌｏｔ分析,初步确     

紫云英细胞转化条件的研究

研究了紫云英（ＡｓｔｒａｇａｌｕｓｓｉｎｉｃｕｓＬ．）细胞遗传转化的条件。根癌农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍｔｕｍ ｅｆａｃｉｅｎｓ）经含乙酰丁香酮的低ｐＨ／ＰＯ３－４ 诱导培养后,用来感染紫云英下胚轴原生质体,随后的细胞ＧＵＳ瞬间表达活性显著提高,间接证明了上述预培养诱导活化了细菌ｖｉｒ基因,促进了Ｔ－ＤＮＡ 向植物细胞转移。在ＰＥＧ介导的ＤＮＡ 转移中,较高的ｐＨ 和Ｃａ２＋ 浓度能够提高细胞ＧＵＳ活性。质粒ＤＮＡ 浓度及启动子类型对外源基因在植物细胞内表达也有一定影响。采用外植体－农杆菌共培养法,获得ＧＵＳ和ＮＰＴ Ⅱ基因稳定表达的紫云英转化植株     

芸苔属脱外壁花粉的分离与人工萌发

芸苔属青菜（Ｂｒａｓｓｉｃａ ｃｈｉｎｅｎｓｉｓ）与紫菜苔（Ｂ． ｃａｍ ｐｅｓｔｒｉｓｖａｒ． ｐｕｒｐｕｒｅａ）的花粉经低温水合、热激、渗激三步程序,分离出大量具萌发能力的脱外壁花粉,脱外壁率可高达６０％ 以上。在含有碳源与氮源及Ｒｏｂｅｒｔｓ培养基盐成分的碱性ＰＥＧ 培养基中,首次使芸苔属脱外壁花粉萌发,萌发率可达３３％ ～４１％ 。在扫描电镜下观察了花粉脱外壁与萌发的过程。讨论了不同植物花粉脱外壁的方法与花粉壁生物学特点的对应关系,以及外壁对花粉萌发的可能作用     

遗传转化花粉长成单倍体植株

日本Ｈｉｒｏｓｈｉｍａ大学和Ｋａｇａｗａ大学的Ｍ．Ｎｉｓｈｉｈａｒａ和Ｈ．Ｍｏｒｉｋａｗａ及其同事报道,他们从用粒子轰击法转化的花粉第一次获得了稳定的转基因单倍体植株。Ｎｉｓｈｉｈａｒａ等人用含有新霉素转移酶Ⅱ（ＮＰＴⅡ）和β－葡糖苷酸酶（ＧＵＳ）基因的质粒ＤＮＡ包被的金粒,转化烟草属Ｎｉｃｏｔｉａｎａｒｕｓｔｉｃａｎａ的未成熟花粉。从被轰击的花粉再生了卡那霉素抗性花粉胚胎,并从总数为２×１０６个被轰击细胞中获得两个独立的转基因株系。一个同时具有ＮＰＴⅡ和ＧＵＳ活性,另一个只有ＮＰＴⅡ活性。两个…     

日本血吸虫26kD抗原基因在BCG中的表达

研究了外源基因日本血吸虫２６ｋＤ抗原（Ｓｊ２６ＧＳＴ）在卡介苗（ｂａｃｉｌｕｓＣａｌｍｅｔｅ－Ｇｕｅｒｉｎ,ＢＣＧ）、耻垢分枝杆菌（Ｍ．ｓｍｅｇｍａｔｉｓ）和大肠杆菌（Ｅ．ｃｏｌｉ）中的表达．运用重组ＤＮＡ和聚合酶链反应（ＰＣＲ）等分子生物学技术,以表达Ｓｊ２６ＧＳＴ的Ｅ．ｃｏｌｉｐＧＥＸ衍生质粒为模板,经ＰＣＲ得到编码Ｓｊ２６ＧＳＴ的全长ｃＤＮＡ片段．将其按正确的阅读框顺序,克隆到人结核杆菌热休克蛋白（ｈｅａｔｓｈｏｃｋｐｒｏｔｅｉｎ,ＨＳＰ）７０的启动子下游,再将ＨＳＰ７０启动子和Ｓｊ２６ＧＳＴ基因一起亚克隆到Ｅ．ｃｏｌｉ－分枝杆菌穿梭质粒ｐＢＣＧ－２０００中,得到Ｅ．ｃｏｌｉ－分枝杆菌穿梭表达质粒ｐＢＣＧ－Ｓｊ２６．ｐＢＣＧ－Ｓｊ２６电转化入ＢＣＧ和Ｍ．ｓｍｅｇｍａｔｉｓｍｃ２１５５中表达Ｓｊ２６ＧＳＴ抗原,所表达的天然重组Ｓｊ２６ＧＳＴ（ｒＳｊ２６ＧＳＴ）为可溶性蛋白,在ＳＤＳ－ＰＡＧＥ上分子量为２６ｋＤ处可见明显的表达蛋白带．其表达量分别占ＢＣＧ和Ｍ．ｓｍｅｇｍａｔｉｓ菌体总蛋白的１５％和１０％．可见,Ｓｊ２６ＧＳＴ基因能在ＢＣＧ中高效表达．     

马铃薯GBSS基因5‘侧翼区调控作用的研究

将０．４、０．８、１．６、２．９ｋｂＧＢＳＳ基因的５＇侧翼区与ＧＵＳ基因融合,构建了双元表达载体。０．８ｋｂＧＢＳＳ－ＧＵＳ通过基因枪介导在块茎切片中获得了瞬间表达。以上建构物通过农杆菌介导转入了马铃薯。Ｘ－Ｇｌｕｃ染色及ＰＣＲ结果证实已获得转基因植株。利用离体块茎诱导系统,ＧＵＳ表达用荧光进行定量检测,结果显示,２．９、１．６、０．４ｋｂＧＢＳＳ－ＧＵＳ的表达均以块茎明显高于茎段,达２￣１０倍。     

利用同源重组提高外源GUS基因在植物组织中表达

将１８Ｓ ｒＲＮＡ基因的部分片段,或烟草的核骨架结合序列（ＳＡＲｓ）作为同源序列与外源ＧＵＳ基因作为报告基因构建成用于基因打靶载体,以枪或农杆菌介导转化到拟南芥的根组织中,检测ＧＵＳ基因瞬间表达的结果显示,两种同源基因序列均可提外源ＧＵＳ基因的表达。     

异戊烯基转移酶基因在转基因烟草中的特异性表达

来自农杆菌（Ａｇｒｏｂａｃｔｅｒｉｕｍ ｔｕｍ ｅｆａｃｉｅｎｓ）的细胞分裂素生物合成基因——异戊烯基转移酶基因（ｉｐｔ）与矮牵牛（Ｐｅｔｕｎｉａ ｈｙｂｒｉｄａ Ｖｉｌｍ ．）中的磷酸核酮糖羧化酶小亚基启动子（ＳＳＵ）融合后转入烟草（Ｎｉｃｏｔｉａｎａ ｔａｂａｃｕｍ Ｌ．）。在转基因烟草中研究了这种嵌合基因的特异性表达,并且测定了内源细胞分裂素水平的变化。结果表明,矮牵牛的ＳＳＵ 启动子能够特异性地控制ｉｐｔ基因在烟草中的表达     

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.