RNA原位杂交技术及其在植物基因表达研究中的应用

原位杂交 ( In situ Hybridization)是一种在细胞水平上研究基因表达调控的最直接有效的分子生物学技术。这一技术最初应用于动物染色体上的基因物理定位 〔1〕和特定 m RNA在组织中的空间定位〔2〕,后来又作为诊断工具检测感染病毒的细胞 〔3〕。到 80年代后期 ,原位杂交技术开始应用于植物基因表达调控的研究 〔4～ 6〕。植物基因的时空表达研究是探讨植物生长发育机制的重要手段。由于 RNA原位杂交技术能够精确确定基因表达的时空分布 ,而得到了越来越广泛的应用 ;从营养器官生长发育〔7～ 9〕、生殖器官生长发育〔10～ 13〕、自交不…     

中国榆科植物系统分类研究综述

榆科 (Ulmaceae)植物 1 6属近 2 30种 〔1〕,广布于世界温带及热带地区 ,主产北温带 〔2～ 4〕。榆科具高度稳定性和适应性 ,现存的各属、组及主要种早于新世即已存在。据化石孢粉学分析 ,第三纪时 ,我国东北、华北及西北就有榆科分布。我国现共有榆科植物 8属 ,分别为榆属 (Ulmus) ,朴属 (Celtis) ,糙叶树属(Aphananthe) ,山黄麻属 (Trema) ,白颜树属 (Gironniera) ,榉属 (Zelkova) ,刺榆属 (H emiptelea)和青檀属(Pteroceltis) ,46种 1 0变种 ,分布遍及全国 〔1〕。Mirbel最初描述榆科时 ,只有榆属和朴属 〔5〕,以后逐渐增多。但自此…     

淹涝胁迫对水稻叶鞘和叶片中淀粉粒分布的影响

淹涝是世界上当前所面临的最严重自然灾害之一,尤其是近几年来,淹涝给我国的农业生产带来了巨大损失,全国平均每年受涝面积814万hm2,其中成灾面积448万hm2,损失粮食约28亿kg〔1〕。水稻是我国的主要粮食作物,并且分布于淹涝易发生的南方多雨潮湿地区和北方低洼地带,淹涝对水稻产量影响极大,因此,研究淹涝胁迫对水稻的伤害及水稻的耐淹机制越来越受到人们的重视〔2〕。淹涝对植物的伤害并非是因为水分过多而造成的直接伤害,而是由于淹涝造成的次生胁迫,其中最严重的是缺氧。在缺氧条件下,细胞中的碳水化合物代谢途径改变,对植物的生长和发育…     

植物叶片衰老过程中的基因表达与调控

衰老是一种器官或组织逐步走向功能衰退和死亡的变化过程〔１〕。它除了代表器官或组织生命周期的终结之外,在发育生物学上也有着重要的意义。叶片的衰老是植物的一个重要发育阶段。在这段时期内,植物在成熟叶片内积累的物质,包括大量的氮、碳有机化合物和矿物质,将被分解并运送至植物其它生长旺盛的部分,其中大部分被转移到种子内,为下一代的生长做好准备〔１１〕。对于产生种子的作物,包括绝大多数农作物,这种转移使营养重新分配,对植株保持正常的生长发育与繁殖是十分必要的〔３〕。衰老过程中,叶片细胞在组成成分上有很大的变…     

世界著名观赏树种——珙桐

珙桐(Davidia involucrata Baill.),英文称为“Dove-tree”(鸽子树),是特产于我国的单型属(Monotypic genus)植物;属于种子植物,珙桐科(Davidiaceae),珙桐属(Davidia)的落叶乔木。原属紫树科(Nyssaceae),珙桐属,因与紫树科另外两属特征上有显著的不同,现已独立成珙桐科。珙桐只一种,并有一变种:光叶珙桐[Davidia involucrata Baill. vat. vilmoriniana(Dode)Hemsl.],特产于湖北省神农架山地。     

土壤氮素与光照对盆栽珙桐幼苗光合参数的影响

珙桐是我国特有珍稀保护物种,在植物系统发育和地史变迁研究上有很高的学术地位,国内外学者进行了大量的研究。以濒危植物珙桐(Davidia involucrate)一年生幼苗为试验材料,通过控制土壤氮素含量与光照的方法,研究了不同土壤氮素含量(0mg、200mg、400mg、600mg、800mg)及是否遮光对珙桐幼苗生长和光合参数的影响,探讨土壤氮素及光照对珙桐幼苗生长的影响。结果表明:1)高氮素水平可以减缓在非适生环境下生长的珙桐幼苗光合速率的降低;2)适宜的直射光照可能对珙桐等喜阴植物的幼苗的生长是有利的;3)氮素对由遮光引起的光合参数的降低有补偿作用,但仍无法完全抵消由于遮光所引起的净光合速率的降低。     

活化石——珙桐

珙桐,也叫鸽子树,是我国特有的稀珍植物,也是世界著名的观尝树种。因为它开花时,两个洁白的大苞片象鸽子栖息于枝头,所以得此美名。珙桐是植物中的“活化石”之一。大约在数百万年     

荷叶铁线蕨等位酶分析初步研究

荷叶铁线蕨 ( Adiantum reniforme var.sinense)是铁线蕨科铁线蕨属肾叶铁线蕨的一个变种〔1〕,分布于重庆市万县、石柱等县的沿江近 1 0 0 km长的狭长地段 ,分布高度局限于海拔 80～ 430 m之间 〔2〕。受其自身生物学、生态学习性的局限和人为的破坏 ,该物种正濒于灭绝的边缘。三峡工程修建后 ,库区内1 75m线以下的地区将被淹没 ,将更加剧该物种的濒危程度。为了挽救这一物种已经采取了许多措施 ,迁地保护是其中的重要措施之一 ,中国科学院武汉植物研究所在这一方面已经做了一些工作 〔3～ 5〕。为了有效地实施迁地保护 ,保存该物种的大部…     

珙桐生物学研究进展

珙桐是我国特有的珍稀濒危植物,国内外学者对其进行了大量研究。目前对珙桐的研究主要集中在珙桐的形态描述、地理分布、种群和群落生态以及引种繁殖等方面。而对其发育生物学,特别生殖过程等研究较少。即便是研究较多的生态学方面也仅仅局限在宏观描述方面,未形成一个完整的系统。今后有必要对这些方面进行研究以更好的保护这一物种资源。     

珙桐幼苗生理生化指标对重金属铅、镉胁迫的响应

铅和镉在土壤中表现出很强的毒性,严重危害植物的生长发育.该研究着眼于中国特有濒危珍稀植物珙桐,探究盆栽实验条件下其抗氧化酶活性、丙二醛(MDA)以及游离脯氨酸、可溶性蛋白对不同浓度重金属铅、镉胁迫的响应规律.结果表明:(1)不同浓度铅处理下,珙桐幼苗MDA浓度均显著高于对照组,而镉胁迫条件下除10 mg·kg-1浓度外...     

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.