知母绒毡层和乌氏体细微结构的研究

从个体发育来看,知母绒毡层具有3个明显的特点;（1）在小孢子母细胞阶段,绒毡层细胞中有丰富的细胞器,如粗糙内质网,脂体,造粉体和小泡等,粗糙内质网－脂体－小泡常常联系在一起,形成细胞器复合体。（2）在单核花粉阶段,绒毡层细胞质中出现大量小泡,它们可以融合成小泡,而且在小泡或大泡中开始沉积与脂体电子密度相似的亲锇物质,这些物质或者充满整个小泡,或者沉积在小泡周缘,此刻,也是乌氏体形成并达到高峰的阶段。（3）在成熟花粉阶段,绒毯层细胞几乎被具膜束缚的小型脂粒和巨型脂体所占据,这些亲锇物质是质体起源的,也许它们是花粉鞘的先质。     

白皮松绒毡层细胞超微结构的研究

白皮松绒毡层细胞的细胞器是十分丰富的,其中粗糙内质网、核糖体和造粉体在减数分裂过程中达到高峰。小孢子形成时,绒毡层细胞开始解体,内质网和线粒体是最后衰老的细胞器。在单核花粉形成时,处于绒毡层细胞外切向壁上的周绒毡层膜特别明显。但是,孢粉素体却主要分布在内切向壁和径向壁上。有趣的是,绒毡层细胞中的造粉体结构与壁层细胞不同。而且,脂体在二分体阶段基本消失,相反,此刻孢粉素体却在质膜外大量聚集。推测脂体的消长可能与原乌氏体和孢粉素体的形成有关。     

棉花花粉水合和萌发时超微结构的变化：着重论述内质网和被膜小泡

棉花(Gossypium hirsutum L.)花粉在授粉后水合至萌发时期的营养细胞中贮藏的大量淀粉粒和脂体被动用。超微结构的观察表明,首先是造粉质体中的淀粉粒降解,尔后是脂体。在花粉水合至萌发时期,营养细胞中内质网和高尔基体十分活跃,并含丰富的被膜小泡。内质网的构型发生明显的变化:花粉刚水合时内质网潴泡高度扩张,不同程度扩张的内质网潴泡连续成网状并折迭形成许多囊袋状结构单位,其中包含造粉质体、脂体和被膜小泡群;其后,内质网潴泡形成的囊袋状结构消失,变为分支互通的网状结构;至萌发时,内质网潴泡略为扩张,有些连续成简单的网状,有些呈游离的囊泡状。被膜小泡始终是成群地分布,并与脂体联结,当脂体降解时一些被膜小泡与之融合。根据棉花花粉在水合至萌发时期,营养细胞质中存在独特形态的内质网系统和含丰富的被膜小泡,它们的动态行为及与淀粉和脂体的转化和降解之间的密切关系,讨论了这两种细胞器可能的功能。     

巴戟天花药发育过程中多糖和脂滴分布特征

巴戟天花药发育中多糖和脂滴类物质的分布呈现一定的规律：减数分裂之前,花药壁的绒毡层细胞中有少量脂滴,其他细胞中脂滴和淀粉粒都很少。四分体时期,四分体小孢子中开始出现脂滴,绒毡层细胞中的脂滴较以前增加,其他细胞中的脂滴和淀粉粒仍然很少。小孢子早期,游离小孢子在其表面形成了花粉外壁,靠外壁下方有一层周缘分布的多糖物质。绒毡层细胞中的脂滴明显减少。发育晚期的小孢子中形成一个大液泡,细胞质中出现淀粉粒;同时在药壁和药隔组织中也出现了淀粉粒。此时绒毡层退化。在二胞花粉早期,花粉中积累了大量淀粉粒和一些脂滴。但在成熟的花粉中（二胞花粉晚期）,淀粉粒消失,只有一定数量的脂滴保留。巴戟天成熟花粉中积累的营养物质主要为脂滴。     

云南松小孢子发生及发育的超微结构研究

造孢细胞具有丰富的细胞器,胞间连丝明显。花粉母细胞中除有大量的细胞器外,还观察到由粗糙内质网环绕成的结构——同心圆内质网。它们形态各异,单独或成群分布,有的中央还环绕着淀粉粒。这在松属植物花粉母细胞中还未见有报导。此时期的绒毡层细胞内具大量成束聚集平行排列的内质网。四分体时期,绒毡层细胞通过质膜和内平周壁向药囊内分泌前乌氏体和孢粉素颗粒。生殖细胞与管细胞由一月牙形薄壁分隔,此两细胞在位置,形态以及内含物上均存在着差异。这决定了它们在雄配子体进一步发育中;有着不同的发育途径和功能。 本世纪六十年以后,对松属植物小孢子发生及花粉形态结构等方面的电子显微镜研究已积累了一些资料。有关云南松胚胎学方面的超微结构研究除刘成运等(1986)对云南松小孢子发生的超微结构进行了研究外,对其小孢子整个发生发育过程的超微结构变化的研究,至今未见有详细报道。因此,对这方面的系统研究是具有一定的理论意义。     

莼菜绒毡层细胞中核糖体的解体与花粉外壁蛋白的形成研究

莼菜（Ｂｒａｓｅｎｉａ ｓｃｈｒｅｂｅｒｉ Ｇｍｅｌ）的绒毡层属腺质绒毡层。四分体时期是绒毡层细胞发育的高峰期,大量膨胀的内质网互相连接,在切面网格构布满细胞,用三维空间结构分析,内质网从多的小室,每个小室中充满核糖体。四分体发育后期,内质网小室中的核糖体开始解体,形成高电子密度的球形体,内质网消失后,从金钱求证菜体游离于细胞基质中。花粉单核期,球形体通过质膜进入花粉囊。在花粉外壁形成 ,球形体不     

地黄绒毡层二型性的超微结构研究

地黄的花药绒毡层具二型性,来源于初生壁细胞的ｐ－绒毡层,细胞较小,为分泌型绒毡层,在小孢子阶段产生乌氏体,于两细胞花粉阶段解体,来源于药隔的ｃ－绒毡层细胞较大,解体的时间早于ｐ－绒毡层,不同药室的ｃ－绒毡层解体的起始时间不一致,可始于小孢母细胞减数分裂,四分体或小孢子阶段,其径向壁面向药室的壁也较早地开始解体,细胞质碎片与细胞器流入药室,分散在小孢子之间,较早解体的ｃ－绒毡层细胞不产生原乌氏体与乌     

水稻花药绒毡层及乌氏体的超微结构观察

在花粉母细胞期,水稻花药绒毡层细胞原生质浓,细胞器丰富,各轴向壁厚度较一致．随着药室腔扩大,绒毡层细胞体积迅速增大,且外切向壁增厚,径切向壁部分区域消失,细胞间形成原生质桥．在单胞花粉早期,乌氏前体排列于绒毡层内切向细胞膜内,随后移向膜外,且外侧增厚形成乌氏体．在花粉单核靠边期,绒毡层细胞的细胞器开始解体,到花粉充实期完全解体,但乌氏体结构直到花粉成熟保持不变．     

麻疯树小孢子发育的研究

用透射电镜观察了麻疯树(Jatropha curcas L.)小孢子发育的超微结构。小孢子母细胞时期内质网和质体较多;减数分裂和四分体时期,细胞处于明显的代谢活跃状态,细胞器丰富,主要有内质网、线粒体、质体、高尔基体和球状体;在小孢子发育早期和晚期,线粒体和内质网仍较丰富;小孢子经过高度的不对称分裂后,形成较大的营养细胞和较小的生殖细胞,营养细胞中细胞器数量明显减少,含大量的淀粉和脂类物质,生殖细胞中脂类物质丰富;表皮、药室内壁和中层细胞在小孢子母细胞和四分体时期淀粉粒丰富,小孢子时期明显减少,绒毡层从小孢子母细胞至小孢子发育晚期的细胞器都很丰富,主要为内质网、质体和线粒体,为二胞花粉发育奠定基础。     

大葱小孢子母细胞至二胞早期花粉发育的超微结构观察

用电镜观察了章丘大葱 (AlliumfistulosumL .)从小孢子母细胞至二胞早期花粉发育的超微结构。终变期的花粉母细胞 ,胼胝壁外方的相邻初生壁间及胞间隙内 ,存在胞间物质 ,四分体期 ,此物质尚部分存在。小孢子母细胞减数分裂前 ,细胞质内含有脂滴 ,小孢子有丝分裂以后 ,脂滴增多增大。小孢子分裂后期 ,质体已积累淀粉粒 1至多个。二胞早期花粉之营养细胞质内 ,有些含淀粉质体亦含脂滴。各发育期 ,核糖体及多聚合糖体丰富 ,并有很多的粗面内质网、高尔基体及小泡、线粒体 ,显示蛋白质、糖类及其它物质合成及运输作用的活跃。小孢子缺中央大液泡。有丝分裂后期 ,细胞器集中于未来的营养细胞极。小孢子胞质分裂期 ,有些内质网贴近或与花粉质膜相连 ,它们或有可能互相融合 ,扩大质膜面积而适应花粉的生长。还讨论了不同时期高尔基体小泡的作用。     

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.