海洋尾丝虫无性生殖期间口器发生的再研究

利用蛋白银技术研究了海洋纤毛虫—海洋尾丝虫无性生殖期间的口器发生过程。结果显示其口器发生与已知的同属种类具相似的过程和形式。其口器发生及演化的基本模式可表示如下 :后仔虫的小膜 1、小膜 2来源于老口侧膜后段的增殖 ;后仔虫的口侧膜及盾片来源于老口侧膜前段的增殖 ;后仔虫的小膜 3来自于老口区盾片的增殖 ;前仔虫的口侧膜及盾片来源于老口侧膜 ,三片小膜在口器发生过程中被保留。文中根据现有的形态发生资料对尾丝虫科的系统关系进行了探讨     

海洋纤毛虫--水滴伪康纤虫的口器发生及形态学重描述

利用蛋白银法对采自山东胶州育虾池的一种海洋盾纤类纤毛虫,水滴伪康纤虫(Pseudocohnilembus persalinus Evans&Thompson,1964)的口器发生过程进行了详细的观察和研究,并对其形态学做了补足性描述。文章通过对该青岛种群发生过程的研究,认为前人所报道的种群(Evans&Thompson,1964;Pomp&Wilbert,1988)缺乏对某个发生关键时期的观察而存在着错误,即:后仔虫的小膜2明确来自老的口侧膜,而不是前人报道的盾片。此外,文章还发现该种的发生与本属另一哈氏伪康纤虫的发生过程几乎完全相同。主要细胞发生过程为:盾片最先增殖,形成初级原基区,然后分裂成前后两部分,前部分最终消失,而后部分最终形成后仔虫的小膜3。继盾片增殖之后口侧膜的锯齿状结构沿细胞纵轴方向分裂成两列,右侧的一列增殖形成次级原基区,之后分裂成前后两部分,前部分迁移形成后仔虫的口侧膜和盾片,后部分形成后仔虫的小膜1和小膜2;老口侧膜的残余部分形成前仔虫的口侧膜及盾片。老的小膜1、小膜2和小膜3则完全为前仔虫所继承。     

海洋纤毛虫--冠帆口虫的口器发生

对海洋盾纤目纤毛虫,冠帆口虫(Pleuronema coronatum)无性分裂期间口器的发生过程做了跟踪观察。结果显示其口器发生与已知的同属种普氏帆口虫具相似的过程。其口器发生及演化的基本模式可简述如下：老口区的三片小膜经历一个分化和移行过程;前仔虫的口侧膜来源于老口区的口侧膜;后仔虫的小膜1～3与口侧膜均来源于老的口侧膜;在口器发生过程中,前、后仔虫口侧膜的后端均形成一个相应的盾片区,其内的毛基粒在进入营养期之前被完全吸收[动物学报49(6)：829～834,2003]。     

尖前口虫的口器发生研究(纤毛门, 膜口目)

研究了咽膜类纤毛虫尖前口虫无性生殖期的核器及口器的演化.其发生特征为;1)新的口原基形成于原前庭动基列与口侧膜间,表观为原口侧膜分裂而致;2)随着形态发生的进行,由口原基依次演化出后仔虫的三片咽膜、口侧膜和三条前庭动基列;3)原口器完全被前仔虫所继承;4)体纤毛器在整个形态发生过程中一直保持双动基列结构.       

毛尾刺虫无性生殖周期中的形态和形态发生

利用蛋白银染色法研究了毛尾刺虫的形态及无性生殖周期中的形态发生,其过程为：（１）后仔虫口原基出现在左缘棘毛内侧深层,其内的毛基体组装成整齐排列的小膜并分化成新ＡＺＭ１,ＡＺＭ２和口侧膜,（２）前仔虫口原基出现在老仔虫ＡＺＭ２之前方深处,其随后发育成前仔虫的ＡＺＭ２口侧膜及ＡＺＭ１的一部分,并更新老结构的ＡＺＭ１中第７－１１片小膜,（３）额腹横棘毛原基为５列,分别以３：３：２：２：３方式分化最终产出     

伍氏游仆虫二分裂和接合生殖期间的形态发生

用改进的银浸法和黑色素法研究了伍氏游仆虫在二分裂和接合期间的形态发生。在二分裂期间前仔虫继承亲体的口围带和口侧小膜。新伸缩泡开口起源于两组额腹横棘毛原基中的第5棘毛场。看清了接合期间两次形态发生的细节。在营养期口围带上见到的小膜第三排动体的骤然变换,已被证明起源于接合时第一次形态发生的不完整的口围带后端的保留。讨论了游仆虫与其它腹毛类在形态发生上的同源问题。     

鲤斜管虫的形态及形态发生的研究

本文报道了鲤斜管虫的形态、纤毛下器、核器、银线系及形态发生过程。其腹面口区具二环围口纤毛列及一口前纤毛列;背面具一列背刚毛;腹面纤毛列的数目可发生较大变动。在其形态发生过程中,左纤毛列在右纤毛列发生断裂前同时断裂;短基粒列形成后仔虫的背刚毛;前仔虫保留原口管前端部分,后仔虫的口管重新形成。本文还对鲤斜管虫的形态学特征、口管形成机理及分类问题等进行了讨论。     

冠突伪尾柱虫的腹皮层纤毛器微管胞器及其形态发生

应用荧光紫杉醇直接荧光标记和抗α-微管蛋白抗体免疫荧光标记方法,显示冠突伪尾柱虫腹皮层纤毛器微管胞器由口围带、波动膜、额腹横棘毛和左右缘棘毛等纤毛器微管、纤毛器基部附属微管等组成。口围带基部含小膜托架及与托架相联系的肋壁微管,其中领部小膜托架间由"∧"形微管相联接;额腹横棘毛基部含前纵微管束、后纵微管束、横微管束和周围微管束,其微管在不同棘毛基部的发达程度不一,其中两列中腹棘毛基部微管紧密联系成一条粗绳索样结构,且左、右中腹棘毛基部的横微管束定向相反;左、右缘棘毛基部含前纵微管束、后纵微管束和横微管束,其中横微管束不发达。与目前已知的腹毛目纤毛虫例如贻贝棘尾虫、魏氏拟尾柱虫的纤毛器基部微管相比较,冠突伪尾柱虫腹皮层纤毛器基部微管除具有腹毛目纤毛虫纤毛器基部微管的基本特征外,也具有一些特殊的组成模式。皮层纤毛器微管形态发生中,前仔虫口围带并非全部是由老口围带更新而来的,其老口围带只有翻领部发生更新,且翻领部与领部接续处有一小段老的翻领部小膜保留,领部的小膜保留,结果其领部小膜、接续处保留的小膜与更新的翻领部小膜三部分共同组成前仔虫的新口围带。在后仔虫口原基发生的位置,其邻近的老横棘毛没有变化,此时老的横棘毛或许能起到"参照点"或定位作用;各类纤毛器发生、分化过程中,处于非原基区的老额棘毛、横棘毛及左右缘棘毛在较长时间内均未见明显的变化。它们可能是在新结构形成时仍然起到运动作用继而逐渐失去功能而退化瓦解的。     

无恒拟小胸虫的形态及形态发生

拟小胸虫属(Pseudomicrothorax)是一类稀见的淡水纤毛虫,至今只发现了两个种。1958年以前这个属归全毛类(Holotricha)毛口亚目(Trichostomata)(Kahl 1931;Kudo,1954)。Thompson及Corliss(1958)用银浸法研究了无恒拟小胸虫(P.dubius)的形态及形态发生,发现其口胞器的结构与原属的毛口亚目无任何共同之点,而与膜口目(Hymenostomatida),特别是四膜亚目(Tetrahymena)相似。因此他们将其归属于膜口目。早     

魏氏拟尾柱虫腹皮层纤毛器微管胞器的形态及形态发生

应用荧光紫杉醇直接荧光标记和抗α-微管蛋白抗体免疫荧光标记显示,魏氏拟尾柱虫(Paraurostyla weissei)腹面皮层纤毛器微管胞器由口围带、波动膜、额腹横棘毛和左右缘棘毛等纤毛器微管、纤毛器基部附属微管等组成。其中口围带基部微管包括小膜托架、小膜附属微管;额腹横棘毛和左右缘棘毛基部附属微管包括前纵微管束、后纵微管束和横微管束,它们由各自的纤毛器基部向皮层细胞质不同方向发射,形成腹皮层表面下微管网。结果表明,魏氏拟尾柱虫的纤毛器骨架、纤毛器附属结构也是一类以微管蛋白为基本成分的微管胞器,其中缘棘毛基部附属微管具有不同于其他纤毛虫(例如棘尾虫)中所观察到的同种微管胞器的建构特征。形态发生中,前仔虫口围带在老结构位置形成,其结构建成与部分老口围带的更新有关;老缘棘毛的结构物质对新的左、右缘棘毛的发生可能具有定位作用及物质贡献,但此后新的左、右缘棘毛列分别在老缘棘毛的右侧形成,而并非是在老缘棘毛位置分化的。在有些细胞中,新的左缘棘毛左侧另有一列棘毛,这可能是形态发生中老的左缘棘毛退化不完全产生的。     

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.