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喙果绞股蓝黄酮类化合物的分离及结构测定 总被引:5,自引:0,他引:5
从喙果绞股蓝(Gynostemma yixingenseC.Y.WuetS.K.Chen.)的茎叶分离到7种化合物:喙果黄素(yixingensin)(I)、山奈酚(kaempferol)(I)、商陆素(ombuin)(Ⅲ)、商甙(om-buoside)(Ⅳ)、槲皮素(quercetin)(V)、异鼠李素(isorhamnetin)(Ⅵ)和硬脂酸(Ⅶ)。其中,喙果黄素为新的黄酮甙,通过光谱分析及化学反应鉴定为商陆素一3-O-β一D一葡萄糖成。 相似文献
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绞股蓝雌雄种群觅源行为和繁殖对策比较 总被引:6,自引:0,他引:6
绞股蓝(Gynostemma pentaphyllum)雌雄异株,种群性比偏雄。作者利用比较生态学方法,从行为生态学角度探讨相同生境中绞股蓝雌雄种群的觅源行为和繁殖对策,得到如下初步结果和结论:(1)绞股蓝雄性种群的主枝生物量比显著大于雌性种群,这意味着雄性种群的营养繁殖投资显著增加,而两性种群在其它结构中的生物量分配无显著差异;(2)雌性种群的叶面积比和单位叶面积比雄性种群显著增加,这与两性种群 相似文献
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四种风毛菊属植物的核型研究 总被引:14,自引:0,他引:14
本文首次报道产于我国华北地区风毛菊属(SaussureaDC.)4种植物的染色体数目和核型。四个种的染色体数目均是2n=26,都是2倍体。它们的核型是:糠风毛菊(S.Paleata)Zn=2x=26=18m+6sm+2st,属2B型,华北风毛菊(S.mongolica)Zn=2x=26=14m+4sm+8st,属2B型;狭苞凤毛菊(S.dielsiana)Zn=2x=26=8m+12sm+6st,属2C型;银背凤毛菊(S.nivea)2n=2x=26=18m+6sm+2st,属2A型。染色体中均未发现随体。 相似文献
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绞股蓝抗肿瘤的药理和临床研究进展潘扬,魏菁(南京中医药大学,南京210029)绞股蓝Gynostemmapentaphyllum(Thunb)Mak,为葫芦科多年生草质藤本,又名七叶胆。全世界绞股蓝属植物约有13种,中国有13种,其中7种为我国所特有... 相似文献
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青海南部太白韭4居群的核型研究 总被引:1,自引:0,他引:1
研究了葱属太白韭青海4个居群的染色体数目和核型。结果如下,居群1:2n=2x=16=12m+2sm+2st(2SAT),居群2:2n=2x=16=14m+2st(2SAT);居群3:2n=4x=32=24m+4sm+4st(4SAT),居群4:2n=2x=16=14m+2st(2SAT)+Bs(0-2)。并讨论了多倍体和B染色体形成与分析。 相似文献
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在华南,迄今只在泥盆纪地层中发现豆石介类(leperditiids)。由于它们均具有下垂“V”字型肌痕且此肌痕随时间的推移不断向下延伸,被考虑是豆石介类中一独立的演化支系,并归一新族:Sinoleperditiini。此族,在华南地区含2属和6亚属:Sinoleperditia(Sinoleperditia)Wang,1989,S.(Pseudobriartina)subgen.nov.,S.(Yaosuoleprditia)subgen.nov,Paramoelleritia(Paralaperditia)Sun,1978,P.(Paramoelleritia)Wang,1976和P.(Brevilaperditia)subgen.nov.。重点探讨了此族的起源,演化型式及趋势和绝灭。指出“V”字型或下垂“V”字型肌的功能与闭壳肌可能是异曲同功,起闭壳作用;放射和横向条纹可能是闭壳肌和下垂“V”字型肌频繁收缩所致而不是血管束的痕迹,并可能具有排泻作用;DalelinaSun,1978是ParaleperditiaSun,1978的同物异名;ParaeoloperditiaAdachietIgo,1980属 相似文献
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对2个八倍体C.S-Thinopyrum bessarabicum(AABBDDJJ,2n=8x=56)和Goshawk(GHK)-Thinopyrum elongatum(AABBDDEE,2n=8x=56)的根尖细胞染色体进行C-分带,从中分检出Th.bessarabicum和Th.elongatum的各自染色体进行核型分析,结果表明:Th.bessarabicum和Th.elongatum的 相似文献
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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. 相似文献
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RICHARD E. NORRIS 《Botanical journal of the Linnean Society. Linnean Society of London》1991,106(1):1-40
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. 相似文献
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JOAN VALUÈS MONTSERRAT TORRELL NÚRIA GARCIA JACAS 《Botanical journal of the Linnean Society. Linnean Society of London》2001,137(4):399-407
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. 相似文献
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肝癌中HBV和HCV基因和抗原的分布及意义 总被引:1,自引:0,他引:1
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 相似文献
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H.-R. GREGORIUS 《Biological journal of the Linnean Society. Linnean Society of London》1984,23(2-3):157-165
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. 相似文献
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. 相似文献