核仁小分子RNA的结构、功能与合成

九十年代以来,许多新的核仁小分子ＲＮＡ（ｓｎｏＲＮＡ）陆续被发现。它们的大小一般在几十到几百个核苷酸,能与特定的蛋白质如核纤蛋白（ｆｉｂｒｉｌａｒｉｎ）或Ｔｈ／Ｔｏ自身免疫抗原等相结合生成ｓｎｏＲＮＰ,在细胞中稳定地存在,并且富集于核仁区。ｓｎｏＲＮ...     

核仁小分子RNA

核仁小分子ＲＮＡ屈良鹄（中山大学生命科学学院生物工程研究中心广州５１０２７５）关键词核仁小分子ＲＮＡ（ｓｏｎＲＮＡ）;内含子（ｎｉｔｒｏｎ）;基因（ｇｅｎｅ）;核糖体（ｒｉｂｏｓｏｍｅ）真核生物（ｅｕｋａｒｙｏｔｅ）在真核生物细胞中,除了人们所熟悉的ｒＲＮＡ,ｍＲＮＡ和ｔＲＮＡ之外,还存在着许多小分子ＲＮＡ［１,２］,如核小分子ＲＮＡ（ｓｎＲＮＡ）,核仁小分子ＲＮＡ（ｓｎｏＲＮ）以及细胞过程中的调控活动,具有十分重要的生物学意义[3,4].     

水稻D1snoRNA及其基因的鉴定和功能分析

测定和比较了籼稻（ＯｒｙｚａｓａｔｉｖａＬ．ｓｐ．ｉｎｄｉｃａ）、粳稻（Ｏ．ｓａｔｉｖａＬ．ｓｐ．ｊａｐｏｎｉｃａ）和多年生野生稻（Ｏ．ｒｕｆｉｐｏｇｏｎＷ．Ｇｒｉｆｉｔｈ）ｈｓｐ７０基因第一个内含子中Ｄ１ＤＮＡ以及部分上游序列,并通过Ｎｏｒｔｈｅｒｎ杂交及ｃＤＮＡ序列分析对Ｄ１ＤＮＡ编码的Ｄ１ｓｎｏＲＮＡ进行了实验鉴定。Ｄ１ｓｎｏＲＮＡ属于反义ｓｎｏＲＮＡ家族,它与水稻２５ＳｒＲＮＡ互补序列为１４个核苷酸长。根据理论计算,Ｄ１ｓｎｏＲＮＡ具有指导水稻２５ＳｒＲＮＡ中第８０７位的核糖甲基化功能。Ｄ１ＤＮＡ与Ｃ１ＤＮＡ相隔仅１０５个核苷酸,在内含子中如此短的距离内连续编码两种ｓｎｏＲＮＡ是罕见的,这一结构为研究串联结构的ｓｎｏＲＮＡ转录后加工机制提供了一个良好的研究体系。     

光周期对光敏胞质不育小麦花药发育过程中Ca^2＋—ATPase分布的影响

应用铅沉淀法研究了不同光照条件下泖负质不育小麦Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ Ｌ．）可育花药和不育药药发育过程中Ｃａ＾２＋－ＡＴＰａｓｅ的分布。短日可育条件下,单核早期至成熟花粉,Ｃａ＾２＋－ＡＴＰａｓｅ在花粉表面,外壁内先增加后 和,在花粉内壁及质膜上逐渐增加,在南内分布较少,成熟花粉的营养细胞核仁内有大量Ｃａ＾２＋－ＡＴＰａｓｅ会面２。精细胞核仁内亦有Ｃａ＾２＋－ＡＴＰａｓｅ分布。乌氏体上     

达乌尔黄鼠染色体银染核仁组织者分析

达乌尔黄鼠染色体银染核仁组织者分析ＡＮＡＬＹＳＩＳＯＮＣＨＲＯＭＯＳＯＭＥＳＡｇ－ＮＯＲＳＯＦＣＩＴＥＬＬＵＳＤＡＵＲＩＣＵＳＫｅｙｗｏｒｄｓＣｉｌｅｌｌｕｓｄａｕｒｉｃｕｓ;Ｃｈｒｏｍｏｓｏｍｅ;Ａｇ－ＮＯＲ达乌尔黄鼠（ｃｉｌｅｌｌｕｓｄａｕｒｉｃ...     

豌豆间期细胞核内核仁组织者区排列的非放射性原位杂交定位

以异羟基洋地黄毒甙（ｄｉｇｏｘｉｇｅｎｉｎ）ｓｆｉ ｙｎ ｒ ｒＲＮＡ为探针与多聚甲醛固定的植物根振动切片原位杂交。结合免疫荧光检测分析了豌豆（Ｐｉｓｕｍ ｓａｔｉｖｕｍ）间期细胞核内核仁组织者区的数目、分布和排列。研究结果发现豌豆根尖分生组织间期细胞核内有１－６个被探针分子强烈标记的位点。这些位点呈大小不等（０．２４－１．９８μｍ＾３）的斑点状,分布在核仁的周边,并且与核仁相连。探针标记位点在核     

AgNORs染色在病原菌检测中的特殊应用

ＡｇＮＯＲｓ染色在病原菌检测中的特殊应用胥维勇,杨红,李科,杨群（四川省人民医院病理科．成都６１００７２）核仁组成区嗜银蛋白ＡｇＮＯＲｓ染色法是近年来广泛采用的银浸润染色技术,它在判断细胞增殖状态,区别良恶性肿瘤研究时有一定意义［１］。我们应用ＡｇＮ...     

Ames试验中各类不同样品处理方法的探讨

Ａｍｅｓ试验中各类不同样品处理方法的探讨韩惠娟,查捷（杭州市卫生防疫站,杭州３１０００６）８０年代以来,世界各国对人类肿瘤和遗传病与环境污染关系的认识逐渐加深,更加重视环境污染问题。环境污染为每一个工业国家必须解决的重大问题之一。Ａｍｅｓ试验是目前国...     

植物核仁小分子RNA的研究进展

20世纪60年代末Weinberg等在哺乳动物中发现了第一个核仁小分子RNA(small nucleolar RNA,snoRNA)U3,在这一领域的研究特别是在20世纪90年代以来,陆续发现许多新的核仁小分子RNA。近几年对动物、酵母和植物方面snoRNA的研究进展,使人们大大地加深了对于rRNA加工和转录以及一系列生物调控过程和机制的认识,正如Smith和Steitz所说的那样：“核仁中sno风暴”引起生物界极大的震动。本文重点介绍植物snoRNA的研究。     

石刁柏非胚性细胞与体细胞胚胚体细胞的超微结构研究

对石刁柏（Ａｓｐａｒａｇｕｓｏｆｆｉｃｉｎａｌｉｓ）体细胞胚发生过程中细胞的超微结构进行了观察,非胚性细胞内液泡大,大量的自体吞噬泡出现,胚性细胞内细胞核大,核移中,核仁结构明显,线粒体、质体、核糖体、高尔基体、内质网等细胞器增多,淀粉、脂滴积累,有较活跃的自体吞噬现象,梨形细胞内质体向叶绿体转变。     

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.