白菜核雄性不育系可育和不育花药中Ca2+的分布

研究了白菜(Brassica campestris L. ssp.chinensis Makino)细胞核雄性不育系花药中Ca2 的分布特征.在可育花药发育过程中,减数分裂后花药壁细胞中钙颗粒明显增加.早期小孢子开始积累钙颗粒并特异性地附在小液泡膜上.小孢子分裂后,大液泡消失过程中又伴随着许多钙颗粒附在小液泡膜上,显示出Ca2 与花粉中液泡的形成和分解有关.在不育花药中,最早出现的钙颗粒异常分布是在小孢子母细胞的胼胝质壁中积累了较多的钙颗粒.然而,在小孢子细胞质中钙颗粒一直很少,也不形成大液泡,最后通过细胞质收缩的方式败育.这是首次发现Ca2 参与调控花药发育过程,其异常分布与花粉败育密切相关.     

白菜核雄性不育两用系可育和不育花药ATPase的分布

对白菜核雄性不育两用系可育花药和不育花药的ATPase做了定位分析。可育花药的花粉母细胞核中积累了大量的ATPase反应颗粒,而细胞质中ATPase反应颗粒较少,但在线粒体中特异地聚集了一些大的ATPase反应颗粒。减数分裂后,小孢子细胞质中ATPase反应颗粒明显增加。随着小孢子发育,其细胞质中ATPase反应颗粒逐渐减少,但在线粒体中又特异性地聚集了较多的AT-Pase反应颗粒。当花药发育到二胞花粉时期,花粉和绒毡层细胞中的ATPase反应颗粒已很少了。不育花药的花粉母细胞中呈现较多的ATPase,然而在线粒体中很少。异常四分体小孢子细胞质中虽然有较多的ATPase反应颗粒,但还是通过细胞质收缩和质壁分离方式退化。对可育花药的花粉母细胞线粒体中特异出现的簇状ATPase分布现象进行了分析,讨论了不育花药中花粉母细胞线粒体ATPase的异常与花粉败育的可能关系。     

甘蓝型油菜隐性上位互作核不育材料1665花药败育的细胞学研究

采用石蜡切片方法,对甘蓝型油菜隐性上位互作核不育材料1665的可育株与不育株花药进行细胞学观察.结果显示:(1)不育株花药在花粉母细胞减数分裂时期出现异常,部分花粉母细胞细胞分裂相不均等分裂或分裂异常.导致部分四分体形状异常.(2)不育株绒毡层细胞在四分体时期开始生长膨大,单核花粉时期出现液泡化和巨型化,侵占药室,使得小孢子不能正常释放或无法继续发育;部分释放出的小孢子未及时形成花粉壁,阻碍花粉继续发育.不能发育形成二核期和三核期花粉,导致花药败育.     

枸杞花药发育过程中钙的分布

在枸杞花药发育过程中,用焦锑酸钾沉淀的钙颗粒显示出了一个与花药发育事件有关的分布特征：在孢原细胞时期的花药中钙颗粒很少。在造孢细胞到小孢子母细胞时期,花药中钙颗粒增加。当花粉母细胞进行减数分裂时,花药中的钙颗粒进一步增加,尤其是在小孢子母细胞的胼胝质壁中。在小孢子发育早期,花药药隔部位的绒毡层细胞质中钙颗粒也明显增加并特异性地分布在其内切向壁上。当小孢子被释放出后,钙颗粒开始特异性积累在正在形成的花粉外壁中,尤其在萌发孔的部位聚集了大量的钙颗粒。当小孢子形成大液泡时,其细胞质中的钙颗粒明显减少。在小孢子分裂形成二胞花粉后,在二胞花粉的大液泡中又特异性地出现许多细小钙颗粒。随着二胞花粉的大液泡完全消失,其细胞质中又出现了许多钙颗粒。接近开花时的成熟花粉粒细胞质中,细小的钙颗粒主要分布在营养细胞和生殖细胞中。枸杞花药发育过程中钙的分布特征反映了其参与调控花粉发育过程。     

羽叶薰衣草雄性不育的细胞学研究

用光镜和电镜观察羽叶薰衣草(Lavandula pinnata L.)雄性不育小孢子发育过程的细胞形态学特征.结果表明:羽叶薰衣草花药4枚,每枚花药通常具4个小孢子囊.花药壁发育为双子叶型,从外向内分为表皮、药室内壁、中层和绒毡层4层细胞.减数分裂形成的四分体为四面体及十字交叉型.小孢子的发育过程可分为造孢细胞期、减数分裂时期、小孢子发育早期、小孢子发育晚期.未观察到二胞花粉期和成熟花粉期.羽叶薰衣草花粉败育主要发生在单核花粉时期,细胞内物质解体并逐渐消失变成空壳花粉或花粉皱缩变形成为各种畸形的败育花粉.在此之前小孢子的发育正常.羽叶薰衣草小孢子不育机制体现在绒毡层过早解体、四分体时期以后各细胞中线粒体结构不正常、胼胝质壁与小孢子母细胞脱离、花药壁细胞中淀粉出现时间异常等. 壁发育为双子叶型,从外向内分为表皮、药室内壁、中层和绒毡层4层细胞.减数分裂形成的四分体为四面体及十字交叉型.小孢子的发育过程可分为造孢细胞期、减数分裂时期、小孢子发育早期、小孢子发育晚期.未观察到二胞花粉期和成熟花粉期.羽叶薰衣草花粉败育主要发生在单核花粉时期,细胞内物质解体并逐渐消失变成空壳花粉或花粉皱缩变形成为各种畸形的败育花粉.在此 前小孢子的发育正常.羽叶薰衣草小孢子不育机制体现在绒毡层过早解体、四分体时期以后各细胞中线粒体结构不正常、胼胝质壁与小孢子母细胞脱离、花药壁细胞中淀粉出现时间异常等. 壁发育为双子叶型,从外向内分为表皮、药室内壁、中层和绒毡层4层细胞.减数分裂形成的四分体为四     

温敏核不育小麦可育花药和败育花药发育观察

对温敏核不育小麦百农不育系（Bainong sterility,BNS）的可育和不育花药结构进行对比观察。在减数分裂期、小孢子早期和小孢子晚期,可育花药与不育花药的结构相同。小孢子分裂形成二胞花粉后,可育花粉中随着大液泡的分解,细胞质内含物增加,其中出现一些颗粒状物质。不育花药中,小孢子也可分裂形成二胞花粉,但营养细胞的大液泡不分解,细胞质也不增加,最终花粉中的细胞质消失,花粉败育。该种温敏核不育小麦的花粉败育时间发生在二胞花粉早期,可能和其大液泡没有适时分解有关。花粉败育时间的确定为进一步深入研究该种雄性不育小麦的败育机制打下了基础。     

灯盏花雄性不育种质鉴定与花药发育的细胞学研究

对云南泸西栽培灯盏花群体进行调查,发现了灯盏花雄性不育种质个体,其出现频率约为1.06×10-4.对所发现的灯盏花不育株形态特征及其花药发育过程进行了观察,并对花粉活力进行鉴定.结果显示:(1)灯盏花不育株根、茎、叶形态与正常可育植株基本相似,管状花小,花丝短,花药瘦小,无花粉粒散出或花粉无活力.(2)灯盏花在其花药发育的小孢子母细胞时期、四分体时期、小孢子时期和单核早期,由于绒毡层细胞液泡化、提前解体,不能为小孢子或花粉发育提供所需物质,导致小孢子母细胞和四分体解体,产生无花粉的花药;或小孢子和单核花粉胞内降解,形成不同形状和外壁纹饰的败育花粉.研究认为,灯盏花花药绒毡层异常是其花粉败育的主要原因.     

甘蓝型油菜几个雄性不育系花药发育的细胞形态学研究

选用甘蓝型油菜6个细胞质雄性不育系和1个细胞核雄性不育系为材料,与可育系比较,确定花药发育受阻的时期和方式。根据研究结果,将其雄性不育系分为三类:1.湘矮A,Po-aA,陕2A和7s-3A花药发育受阻于孢原细胞分化期,没有分化形成花粉囊。2.萝AⅠ和萝AⅡ花药发育受阻于四分体至单核花粉期。败育方式为小孢子难以从四分体中释放出来,或释放出来后细胞质液泡化,核不能分裂,花粉壁发育不良。此外,还见到绒毡层径向肥大、延迟消失和维管束分化不良等异常现象。3.宜3A为核不育系,花药发育受阻于花粉母细胞期。败育方式为花粉母细胞死亡,减数分裂异常,或不能进行减数分裂。绒毡层和维管束一般都能正常发育。     

水芹花药发育中Ca~(2+)分布特征研究

应用焦锑酸钾沉淀技术对水芹发育花药中的Ca~(2+)分布特征和生理功能进行分析。在小孢子母细胞的胼胝质壁中聚集了较多的钙沉淀颗粒,其他部位较少。小孢子母细胞减数分裂后,花药药壁和药隔组织中的钙沉淀颗粒明显增加。早期小孢子先在花粉外壁基柱层中聚集了较多的钙沉淀颗粒,在小孢子质膜与花粉外壁之间也特异性聚集了许多钙沉淀颗粒。在小孢子形成大液泡过程中,小孢子质膜内陷形成小液泡,钙沉淀颗粒被包裹到小液泡中,并被转移到大液泡中,显示Ca~(2+)参与了液泡的构建。小孢子不等分裂后,二胞花粉中的大液泡分解,细胞质内含物增加,积累营养储存物——淀粉和脂滴。花粉中的钙沉淀颗粒明显减少,而药壁的表皮和药室内壁细胞中的则增加。成熟花粉中钙沉淀颗粒很少,但在花粉外壁的基柱层空隙中仍有许多钙沉淀颗粒分布。水芹花粉中的Ca~(2+)分布的特点显示其在小孢子发育的液泡代谢过程具有重要的生理功能。     

辣椒细胞质雄性不育花药败育及淀粉粒分布的细胞学观察

用PAS反应对辣椒细胞质雄性不育系8214A和保持系8214B花药中的淀粉粒分布进行研究.在减数分裂前,保持系花药与不育系花药的结构和淀粉粒分布相似.保持系花药减数分裂后,药壁绒毡层细胞开始液泡化并体积增大,在药隔薄壁细胞中积累了许多较小的淀粉粒;在小孢子晚期,绒毡层细胞退化,在药隔薄壁细胞中淀粉粒体积增大;在二胞花粉时期,随着花粉大液泡的消失花粉中出现淀粉粒;花粉成熟时,其细胞质中积累了丰富的淀粉粒.不育系花药减数分裂后,由于药室腔的空间不能扩大,四分体被挤压在一起,最终四分体小孢子败育.不育花药的维管组织发育正常,但较多的淀粉粒积累在药隔薄壁细胞中.该种辣椒雄性不育系中.花粉的败育发生在四分体时期.绒毡层细胞结构异常可能影响糖类物质向药室的正常转运.该种辣椒雄性不育系的绒毡层异常与花粉败育有关.     

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.