瘦尾虫的小核在无性繁殖周期中对细胞形态结构的影响

通过显微切割建立瘦尾虫无小核细胞系,并与原细胞系及切割后再生的有小核细胞系进行对照观察。结果表明,无小核细胞的形态结构,尤其是口器出现高比率的畸形。在生长静止期,无小核细胞系群体中约23 % (36/155)的细胞完全失去了波动膜。与此同时,这些细胞的口围带也显出异常。一些无小核细胞的大核也出现异常,有的细胞仅含有1枚大核,有的则含有4枚,而不是通常的2枚;还有少数细胞的大核在非细胞分裂期进行分裂。上述结果提示,在无性繁殖周期中,瘦尾虫的小核对于维持正常的细胞形态结构、尤其是保持胞口结构的稳定性和大核数的恒定起着重要的作用[动物学报52 (2) : 383 -388 , 2006]。     

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。     

阔口尖毛虫皮层纤毛器微管在不同生理条件下的分化

应用激光扫描共聚焦显微术,显示腹毛类纤毛虫阔口尖毛虫(Oxytricha platystoma)无性生殖过程中,新的口围带、波动膜、额腹横棘毛、左右缘棘毛微管先后分化,老纤毛器微管去分化,细胞分裂产生各含一套纤毛器微管的前、后两仔虫;生理改组过程中,口围带、波动膜、额腹横棘毛、左右缘棘毛微管发生去分化和再分化,细胞皮层微管胞器更新形成含一套纤毛器微管的新细胞。结果表明阔口尖毛虫在无性生殖和生理改组这两种不同的生理条件下,其纤毛器微管结构的形成或更新可能具有相同的细胞调控机制,形态发生中老纤毛器结构可能对新结构的发生和发育具有诱导定位和物质贡献的作用。     

卡龙游仆虫无性生殖期间的形态发生学研究：原生动物,纤毛虫

卡龙游仆虫为海洋中自由生纤毛虫,利用银染法对该种二分裂期间的形态发生学进行了初步的研究,其主要过程为：１．伴随大核改组带的出现和ＤＮＡ复制开始,口原基发生于老口围 方皮膜下一龛腔内,后由前至后组装成围口小膜而演化为后ＡＺＭ。老口围带及口侧膜在原位被被前仔虫继承;２．体棘毛场首先出现两组棘毛原基,其随后各自独立演化成９根前、后仔虫的额－腹－横棘毛;３．缘棘毛原基也为独立发生,初为单一,后断裂为二并分     

念珠伪角毛虫小核体功能初步研究

为了研究念珠伪角毛虫的小核是否具有及具有怎样的体功能,采用显微切割手术去小核并建立无小核细胞系。经蛋白银染色鉴定,无小核细胞系群体中大多数细胞的形态结构存在缺陷：口围带的部分小膜缺损或排列紊乱,大核的数目和形态也不正常。这表明,念珠伪角毛虫的小核对于保持口围带结构的完整性以及大核的数目和形态结构的稳定性起着明确的作用。     

红色角毛虫的形态学和形态发生过程的研究

观察并描述了上海采集到的红色角毛虫的形态结构和形态发生过程。发现形态发生时虫体分别于前、后两个区域发生前、后两个口围带原基,并且由同一个体分裂而成的前,后两个仔虫内,额、腹、横棘毛和缘棘毛的分化并不完全相同,以至造成两个仔虫上棘毛的数目和缘棘毛的列数有明显差异。根据红色角毛虫的形态结构及其形态发生中的一些不够稳定的特点,推测它可能是一种还处于分化中的腹毛类纤毛虫。     

阔口尖毛虫无性生殖和生理改组过程的比较

阔口尖毛虫无性生殖中先后发生后口围带原基,前、后的波动膜原基,额腹横棘毛原基和左、右缘棘毛原基,老口围带也在此期间更新,结果形成2套新纤毛结构,原老结构瓦解消失;生理改组时按同样顺序产生口围带原基等几类腹面纤毛原基,结果形成1套新纤毛结构,替换老结构。在这两个截然不同的过程中,新纤毛结构的分化和老纤毛结构退化时也表现出某些相似的特征。作者据此推测,这种纤毛虫无性生殖和生理改组中,纤毛原基的发生、发育和定位在细胞控制机理上可能是相同的。     

冠突伪尾柱虫生理改组中口器发生及口围带调节重建的研究

在冠突伪尾柱虫生理改组过程中,口器发生分波动膜形成和口围带重建两方面独立进行。前者发生包容了旧波动膜解聚、胞咽壁新产生和左列腹棘毛解体等三个部位的毛基粒;后者重建则由口围带原基新分化的小膜、经过裁剪修饰后的旧翻领部和邻部三者拼接整合而成。新小膜的添加与旧小膜的减少二者之间的所达致的平衡保证了生理改组后口围带结构的稳定性。     

悬游双眉虫(原生动物,纤毛门)无性生殖期间的形态发生

应用蛋白银染色技术研究了悬游双眉虫青岛种群无性生殖期间皮层结构和核器的演化过程,其主要特征为:后仔虫口原基独立地出现于紧靠虫体左侧第一根横棘毛的皮层下小龛,其中毛基粒不参与其它棘毛原基的形成;老的口围带发生后半部的局部重建而非整个的由前仔虫简单继承;在前仔虫中,波动膜原基来自老结构的反分化,而在后仔虫中则来自口原基;所有棘毛原基均为独立发生并与老结构没有任何关系;在前仔虫中,口棘毛(即左侧第一根额棘毛)来自于波动膜的反分化,而在后仔虫中则为独立发生;背触毛列于老的结构当中产生,并由最右一列原基演化出3根尾棘毛;两大核片段的改组带从一端向另一端移动 ,并随着两者的融合而消失.文中同时对前人有关该属发生模式的若干存疑问题做了探讨 [动物学报 54(3):517-524,2008].     

红色角毛虫生理改组过程的研究

红色角毛虫在生理改组时,随着老纤毛器的瓦解,先后出现新的口器,额、腹、横棘毛,左、右缘棘毛和背触毛四个原基区,并发生原基区的分化、新结构的形成和定位。这种新、老结构的更替过程相似于同种纤毛虫正常形态发生时期纤毛器的演化过程,口围带改组时,新口围带原基在左列中腹棘毛左侧的范围形成,后来,随着老口围带的瓦解,它向前方移动并处于老口围带的右侧,并继续朝老口围带位置移动、替换老口围带。这不同于其他常见的腹毛类纤毛虫,生理改组时新口围带原基在瓦解着的老口围带的位置逐渐移动替换老口围带的情况。     

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.