横断山区伞形科4种7个居群植物的核型研究

对横断山区伞形科棱子芹属2种植物(松潘棱子芹Pleurospermum franchetianumHemsl.和西藏棱子芹Pleurospermum hookeriC.B.Clarke var.thomsoniiC.B.Clarke)和茴芹属2种植物(异叶茴芹Pimpinella diversi-foliaDC.和锐叶茴芹Pimpinella argutaDiels)共7个居群进行体细胞染色体数目观察和核型比较分析,结果表明,棱子芹属和茴芹属植物属内种间染色体基数存在差异,其中松潘棱子芹为2n=2x=18=16sm 2st,西藏棱子芹为2n=2x=22=16m 6sm;茴芹属光果组中锐叶茴芹为2n=2x=22=22m,毛果组中异叶茴芹为2n=18=18st或2n=18=2sm 16st.松潘棱子芹、西藏棱子芹、锐叶茴芹的染色体数目和核型均为首次报道,从而为棱子芹属和茴芹属的分类和演化研究提供细胞学依据.     

伞形科棱子芹属部分种类果实结构的比较解剖学研究

采用石蜡切片法对伞形科(Apiaceae)棱子芹属(PleurospermumHoffm.)的宝兴棱子芹〔P.benthamii(Wall.ex DC.)Clarke〕和松潘棱子芹(P.franchetianumHemsl.)、西藏棱子芹(P.hookeriClarke var.thomsoniiClarke)和太白棱子芹(P.giraldiiDiels)、康定棱子芹(P.prattiiWolff)和瘤果棱子芹(P.wrightianumde Boiss.)的果实横切面的解剖结构特征进行了详细观察和比较分析。结果表明:6种植物虽然在外部形态上两两相似,但彼此间的果实解剖结构特征却存在一定的差异。共同特征是果棱均比较发达,且外果皮与中果皮分离,常形成空腔,每个果棱有1个明显的维管束,中果皮高度退化,果壁均很薄,棱槽和合生面均有油管,其中合生面油管数为棱槽油管数的2倍;差异主要表现在果实横切面外形、果体的压扁程度、果棱的发达程度、外果皮拱起程度及角质层的有无和厚度、维管束大小和着生位置、棱槽油管数以及合生面与侧棱的关系等方面。根据观察结果认为康定棱子芹与瘤果棱子芹不宜合并,建议将西藏棱子芹与太白棱子芹予以合并。     

中国伞形科棱子芹属植物果实表面微形态特征及其分类学意义

采用扫描电镜方法对中国18种棱子芹属植物的果实表面微形态进行了首次研究,结果表明:所研究的棱子芹属植物果实微形态在外果皮细胞轮廓、表面纹饰和表皮分泌物表现出丰富的多样性和一定的规律性,可作为棱子芹属下分组及种间鉴定的重要参考性状.根据外果皮细胞轮廓及果实表面纹饰类型等微形态特征将所研究的棱子芹属植物分成了3种类型,该结论与形态学和分子系统学研究结果基本一致,说明果实微形态对研究棱子芹属属下分类和鉴别有重要意义,并据此对该属属下个别存疑种及一些种的亲缘关系进行了探讨.综合前人研究,我们支持喜马拉雅地区不仅是棱子属的分布中心,也是其分化变异中心.     

中国棱子芹属16种1变种的果实特征及其分类学意义

采用石蜡切片法对中国棱子芹属植物16种1变种进行了果实外部形态和解剖特征观察,研究了分生果大小、果棱形状、油管数目、胚乳形状等特征,文中探讨了部分棱子芹属植物的分类地位,为该属的系统分类研究及分类问题的解决提供了佐证。主要结论如下:(1)棱子芹属植物果实解剖特征在种间存在明显差异,在种内性状比较稳定。(2)所研究的棱子芹属植物果实在外部形态和解剖结构表现出较高的多态性和一定的规律性,可以为棱子芹属近缘种的鉴定提供重要的参考性状。(3)结合果棱性状、油管数目等解剖结构和前人分子系统学研究证据,研究认为真正的棱子芹属植物其成熟果实外果皮膨胀,果棱远端具空囊,中果皮和维管束形成的内棱较不显著。     

中国棱子芹属植物叶表皮微形态特征及其系统学研究

采用光学显微镜和扫描电镜对棱子芹属(Pleurospermum)11种植物的叶表皮微形态特征进行了观察研究.结果表明:(1)显微观察显示,气孔器普遍存在于叶的下表皮.少数种的上表皮也有分布,多为无规则型;叶表皮细胞形状为多边型或不规则形.垂周壁式样可区分为近平直、平直-弓形、浅波状和波状.(2)扫描电镜观察显示,叶表皮气孔器外拱盖内缘为近平滑、浅波状或波状;角质膜条纹状,有的条纹隆起,有的条纹上附有颗粒和晶簇.(3)气孔器的分布、气孔器外拱盖内缘形态以及角质膜等特征对该属部分种的区分有一定的参考价值.(4)结合外部形态特征,推测康定棱子芹应作为种一级分类群.松潘棱子芹与宝兴棱子芹的亲缘关系比较近.     

高山特有植物丽江棱子芹的叶绿体基因组结构和系统发育关系

本文基于高通量技术对丽江棱子芹(Pleurospermum foetens)的叶绿体基因组进行测序,并对丽江棱子芹的叶绿体基因组结构特征及其系统进化关系进行了分析。结果表明,丽江棱子芹的叶绿体基因组具备典型的四分体结构,基因组全长155 057 bp,包含87个蛋白编码基因、 8个核糖体RNA基因和39个转运RNA基因。生物信息学分析结果显示,叶绿体基因组共编码26 075个密码子,编码异亮氨酸Ile的ATT数量最多,除终止子外编码半胱氨酸Cys的TGC数量最少,相对同义密码子使用度最高的为UUA,最少的是AGC; SSR位点共预测到了34个,包括单核苷酸重复序列27个,双核苷酸重复序列4个,以及复合型重复序列3个。丽江棱子芹与棱子芹属(Pleurospermum)其他植物相比较,其基因组大小、基因类型及GC含量相近。利用IQ-TREE软件构建最大似然树,结果表明丽江棱子芹与线裂棱子芹(P.linearilobum)的亲缘关系最近,棱子芹属为多系类群。该研究丰富了丽江棱子芹叶绿体基因组的遗传信息,为丽江棱子芹的分子标记的开发、遗传多样性和谱系地理研究等奠定了理论基础,同时也为构建伞形科...     

用气相色谱/质谱联用技术分析瘤果棱子芹挥发性化学成分

利用气相色谱／质谱联用仪对采自青海的瘤果棱子芹经二氧化碳超临界萃取(SFE-CO2)及水蒸汽蒸馏(SD)得到的精油化学成分进行分析,分别从不同提取样品中分析鉴定了49种和41种化学成分,其中主要的化学成分是E-9-十八烯酸(9．54％)和1,3,5,7-环辛四烯(15．26％)。     

山药化学成分的研究

从胡椒科植物山蒟中分得两个新木脂素类成分(Ia)和(Ⅱ),以及巴豆环氧素(Crorepoxide)(Ⅲ)和β-谷甾醇(Ⅳ)。经光谱分析及化学鉴定,(Ia)、(Ⅱ)为新结构,分别命名为山蒟素 B(hancinone)、山蒟素 C(hancinone C)。     

伞形科棱子芹属花粉形态特征及其演化意义

采用光学显微镜及扫描电子显微镜观察了国产棱子芹属（Pleurospermum Hoffm．）13个种类的花粉形态特征。结果显示：供试13个种类的花粉粒可分为近菱形、近圆形、椭圆形、近长方形和超长方形5种类型。极轴长度（P）17．1—27．1μm,多为20～25μm;赤道轴长度（E）12．5—19．3μm,多为13．6～18．6μm;PIE值为1．2—2．0,多为1．2—1．5。极面观通常为三角形或近卵状三角形,少数种类为近圆形,仅1种（太白棱子芹Pgiraldii Diels）为三裂圆形;赤道面观多为近菱形、近圆形或椭圆形,少数种类为近长方形,仅1种（太白棱子芹）为超长方形。萌发孔为三沟孔,大多数种类为角萌发孔,仅云南棱子芹（P．yunnanense Franch．）和太白棱子芹为边萌发孔;沟长达两极或几达两极。赤道区的纹饰密集且多样,大体可分为短皱脑纹、颗粒状纹和细网纹3类,其中仅岩生棱子芹[Prupestre（Popov）K．T．FuetY．C．Ho]具细网纹;极区纹饰与赤道区常不一致,多为穴状网纹或纹饰不清晰。依据观察结果,讨论了棱子芹属在伞形科中的演化地位以及属内各种类间的演化关系,并结合宏观形态特征及果实解剖特征探讨了棱子芹（PcamtschaticumHoffm．）、太白棱子芹和矮棱子芹（P．nanumFranch．）的分类问题。     

雪兔子的成分研究

从雪兔子(Saussurea gossypiphora D.Don)中首次分得6种结晶物,经红外光谱、紫外光谱、质谱和核磁共振谱等方法鉴定为:伞形花内酯(umbelliterone)(Ⅰ)东莨菪素(scopole-tin)(Ⅱ),β-谷甾醇(β-sitosterol)(Ⅲ),芹菜素(apigenin)(Ⅳ),芹菜素7-葡萄糖甙(api-genin 7-O-β-D-glucoside)(Ⅴ),伞形花内酯甙(umbelliteione 7-O-β-D-glucoside)(Ⅵ)。     

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.