越南、老挝蕨类植物新记载 （3）——凤尾蕨属

通过野外调查和标本研究,报道越南、老挝两地凤尾蕨属Pteris 7个新记载的物种,它们分别是P.argyraea、四川凤尾蕨P.sichuanensis、两广凤尾蕨P.maclurei、 单叶凤尾蕨P.pseudopellucida、 有刺凤尾蕨P.setuloso-costulata、 琼南凤尾蕨P.morii、 栗轴凤尾蕨P.wangiana.     

凤尾蕨属配子体若干系统学特征新考

通过对凤尾蕨属(Pteris L.)8种,即半边旗(P.semipinnata L.)、傅氏凤尾蕨(P.fauriei Hieron.)、阔叶凤尾蕨(P.esquirolii Christ)、三叉凤尾蕨(P.tripartita Sw.)、蜈蚣草(P.vittata L.)、溪边凤尾蕨(P.excelsa Gaud.)、有刺凤尾蕨(P.setuloso-costulata Hayata)、西南凤尾蕨(P.wallichiana Agardh)孢子的人工培养,观察并总结了该属配子体发育各阶段形态特征,并与以往的观察结果进行比较.最终选取孢子萌发型与配子体发育类型等稳定特征作为判断依据,讨论该属与书带蕨科(Vittariaceae)、中国蕨科(Sinopteridaceae)、铁线蕨科(Adiantaceae)等科的亲缘关系.研究认为蕨类配子体生长点上方边缘细胞分布情况多变,不是稳定的系统学特征.而配子体特定部位边缘细胞的外侧壁形态则具有较高的系统学参考价值.     

基于rps4-trnS区序列的证据分析傅氏凤尾蕨和狭眼凤尾蕨的关系

对傅氏凤尾蕨(Pteris fauriei)和狭眼凤尾蕨(Pteris biaurita)的叶绿体rps4-trnS区序列进行PCR扩增和序列分析,再结合NCBI基因数据库中已发表的凤尾蕨科及其邻近类群的rps4-trnS区序列构建系统发育树来分析两者的亲缘关系。结果显示:傅氏凤尾蕨和狭眼凤尾蕨的rps4-trnS区序列未表现出明显差异。结合两者孢子体和配子体形态发育特征以及rps4-trnS区序列的证据,认为傅氏凤尾蕨和狭眼凤尾蕨为同种或为变种关系。     

越南、老挝蕨类植物新记载（3）——凤尾蕨属

通过野外调查和标本研究,报道越南、老挝两地凤尾蕨属Pteris 7个新记载的物种,它们分别是P.argyraea、四川凤尾蕨P.sichuanensis、两广凤尾蕨P.maclurei、 单叶凤尾蕨P.pseudopellucida、 有刺凤尾蕨P.setuloso-costulata、 琼南凤尾蕨P.morii、 栗轴凤尾蕨P.wangiana.     

凤尾蕨属植物在中国的分布新资料

凤尾蕨属植物具有较高的观赏价值和药用价值。弄清其在我国的分布状况,有利于资源的开发利用。本文报道了台湾凤尾蕨Pteris taiwanensis Ching ex Ching et S. H. Wu为中国大陆分布新记录,另外11种凤尾蕨属植物为省新记录,分别是海南凤尾蕨、指叶凤尾蕨、多羽凤尾蕨、大明凤尾蕨、细弱凤尾蕨、线羽凤尾蕨、栗柄凤尾蕨、单叶凤尾蕨、细羽凤尾蕨、三叉凤尾蕨和鸡冠凤尾蕨。并证实凤仪凤尾蕨Pteris dalhousiae Hook.没有分布至中国。     

广西蕨类植物孢子形态的研究Ⅲ.凤尾蕨科

利用光学显微镜和扫描电子显微镜对广西产凤尾蕨科及其近缘科蕨科、姬蕨科和碗蕨科5属9种植物的孢子形态进行了观察研究,详细描述了9种植物孢子的形态及表面纹饰特征.井栏边草、刺齿凤尾蕨、隆林凤尾蕨、剑叶凤尾蕨、林下凤尾蕨、蕨和碗蕨植物的孢子为三裂缝,辐射对称;极面观为钝三角形,赤道面观为半圆形或超半圆形;栗蕨和姬蕨植物孢子为...     

剑叶凤尾蕨配子体发育的研究

剑叶凤尾蕨(Pteris ensiformis)是凤尾蕨科(Pteridaceae)凤尾蕨属(Pteris)多年生常绿草本植物,具有较高的观赏和药用价值.但是,目前对其繁殖过程还缺乏了解,限制了剑叶凤尾蕨资源的开发利用.本文报道了成功地采用混合土培养剑叶凤尾蕨的孢子,并系统地观察记录其孢子萌发及配子体发育过程.剑叶凤尾蕨的孢子呈褐色,赤道面观豆形,极面观三角形,单裂缝.播种1周左右孢子萌发,萌发类型为书带蕨型,配子体发育为水蕨型.播种3周左右发育为片状体.幼原叶体不对称,成熟原叶体裸露,无毛状体,呈心脏形.播种5周左右开始有性器官出现,精子器由3细胞组成,成熟颈卵器颈部由4列细胞组成,4层细胞高.原叶体受精后1个月内即可观察到从原叶体上生成的幼胚.该研究为园艺学研究提供了用孢子人工繁殖剑叶凤尾蕨的方法,也为分子生物学、遗传学和蕨类植物系统学研究提供了基础.     

贵州蕨类植物新资料

报道了贵州一新记录蕨类植物种--云南三叉蕨和一新变种--畸形岩凤尾蕨.     

凤尾蕨属5种植物孢子体形态研究

采用光学显微镜对凤尾蕨属5种植物孢子体形态特征进行观察和分析,以探讨该属植物的形态和亲缘关系,为凤尾蕨属的系统分类提供新的资料和依据.结果显示,该属5种植物的基本气孔类型为腋下细胞型和极细胞型;叶脉类型为无网眼的羽状分离型;副叶脉呈一回分叉平行分布;5种植物的维管束木质部多为单柱型管状中柱,也有部分双柱型网状中柱,管状分子中均有导管分子存在,仅在蜈蚣蕨和银脉凤尾蕨中发现管胞,其中井栏边草无纹孔膜残余.研究表明,蜈蚣蕨和银脉凤尾蕨较为原始,井栏边草、溪边凤尾蕨、紫轴凤尾蕨关系更近,也更为进化.     

狭眼凤尾蕨配子体发育及其成精子囊素对水蕨配子体发育的影响

对狭眼凤尾蕨（Pteris biaurita）配子体发育特征及其外源成精子囊素对模式植物水蕨（Ceratopteris thalictroides）在黑暗和光照条件下孢子萌发和配子体发育的影响进行了研究。结果表明：（1）狭眼凤尾蕨孢子深褐色,三裂缝,孢子萌发为书带蕨型,原叶体发育为水蕨型,无毛状体产生;培养发现,其配子体能产生精子器,但不产生颈卵器,当接种密度适中时,可进行无配子生殖。（2）在光照和黑暗条件下狭眼凤尾蕨成精子囊素有促进和抑制水蕨孢子萌发的作用,但效果均不显著。（3）在光照条件下,狭眼凤尾蕨成精子囊素可以延迟水蕨心脏形配子体分生组织缺刻的形成,但对其配子体形态和性别分化无明显影响;而在黑暗条件下狭眼凤尾蕨成精囊素对水蕨长条形配子体的形态发育具有一定影响,与对照组相比其顶端分生组织发达,整体呈长楔形,对性别分化影响不显著。可见,狭眼凤尾蕨和水蕨不具有同种成精子囊素系统。     

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.