苦绳的甾体成分

从苦绳(Dregea sinensis var.corrugata)的茎叶中分得一个新的C_(21)-甾体甙元,命名为苦绳甙元(drevogenin)(Ⅰ),经光谱分析和化学反应证明,其结构为:C/D顺式5α—H、3β、8β、14β、17β四羟基-12β-O-异戊酰基-20-O-乙酰基娠烷(C/D 5α-H、3β、8β、14β17β tetrahydroxyl-12β-O-isovaletyl-20-acetyl-pregnane);另外分得一个β-谷甾醇-β-D-葡萄糖甙(β-sitosterol-β-D-glucoside)。     

苦绳甙乙的结构

从苦绳〔Dregea sinensis var. Corrugata (Sohneid.) TsiangP.T. Li〕的根茎中分到一个新的C_(21)-甾体酯甙成分,命名为苦绳甙乙 (DregeosideB),经光谱分析和化学反应证明,其结构为:苦绳甙元乙 3-0-β-D-夹竹桃吡喃糖(1→4)-β-D-磁麻吡喃糖 (1→4)-β-D-磁麻吡喃糖甙〔DrevogeninB 3-0-β-D-oleandropyra nosy1(1→4)-β-D-cymaropyranosy1(1→4)-β-D-cymaropyranoside〕。     

苦绳甙甲的结构

从苦绳(Dregea sinensis var. corrugata)的根茎中分得一个新的C_(21)-甾体甙成分,命名为苦绳甙甲(dregeoside A)。经光谱分析和化学反应证明,其结构为:苦绳甙元甲3-O-3-O-甲基-6-去氧-β-D-阿洛吡喃糖(1→4)-β-D-夹竹桃吡喃糖(1→4)-β-D-磁麻吡喃糖,(1→4)-β-D-磁麻吡喃糖甙(drevogenin A 3-O-3-O-methyl-6-deoxy-β-1)-allopyranosyl-(1→4)-β-D-oleandropyranosyl-(1→4)-β-D-cymaropyranosyl-(1→4)-β-D-cymaropyranoside).     

云南苦绳化学成分的研究

采用硅胶柱色谱、Sephadex LH-20凝胶柱色谱、半制备型HPLC等方法从云南苦绳中分离纯化了6种化学成分。通过红外光谱、一维核磁共振波谱、二维核磁共振波谱、质谱等方法确定其化学结构为二十烷酸(1)、α,γ-二棕榈酸甘油脂(2)、β-谷甾醇(3)、4ɑ-甲基-胆甾-7-烯-3-β-醇(4)、3,4’-二甲氧基-4,9,9’-三羟基-苯并呋喃木脂素-7’-烯(5)、松脂素(6)。化合物1～6均为首次从云南苦绳根茎中分离得到。     

滇藏杜英化学成分研究

通过有机溶剂提取、色谱等手段从滇藏杜英(Elaeocarpus braceanus)分离到17个化合物,根据氢谱(1H NMR)、碳谱(13C NMR)、质谱(MS)等波谱解鉴定分别为3-氨基4-羟基-苯甲酸-1-O-β-D-吡喃木糖甙(1)、3,5,7-三羟基-4'-甲氧基黄酮(2)、杨梅素(3)、5-O-甲基-杨梅素(4)、4'-O-甲基-杨梅素(5)、二氢山奈酚(6)、二氢杨梅素(7)、杨梅素3-O-α-L-鼠李糖甙(8)、山奈酚-3-O-α-L-鼠李糖甙(9)、4'-O甲基-杨梅素3-O-α-L-鼠李糖甙(10)、7,4'-O–二甲基杨梅素3-O-α-L-鼠李糖甙(11)、4'-O–甲基杨梅素3-O-β-D-葡萄糖甙(12)、山奈酚-3-O-β-D-葡萄糖甙(13)、(3β,9β,10α,16α,23R)-16,23-epoxy-3-(β-D-glucopyranosyloxy)-20-hydroxy-9-methyl-19-norlanosta-5,24-dien-11-one(14)、β-谷甾醇(15)、β-胡萝卜甙(16)和3,5-二羟基4-甲氧基苯甲酸(17),其中1为新化合物,其它16个化合物是首次从滇藏杜英中发现。     

中华小苦荬萜类化学成分的研究(英文)

从中华小苦荬全草的乙酸乙酯提取物中分离得到8个萜类化合物,通过波谱方法及文献对照分别鉴定为β-香树脂素(1),3β-羟基-20(30)-蒲公英甾烯(2),熊果-12-烯-3β-醇(3),羽扇豆醇(4),10-羟基艾里莫芬-7(11)-烯-12,8α-内酯(5),乌苏-12,20(30)-二烯-3β,28-二醇(6),3β,8α-二羟基-6β-当归酰基艾里莫芬-7(11)-烯-12,8β-内酯(7)和乌苏酸(8),化合物1～8均首次从该植物中分离得到。     

川西獐牙菜甙类成分

对川西獐牙菜(Swertia mussotii Franch.)的水溶性成分进行了研究。应用层析方法,分离得到裂环烯醚萜甙,黄酮甙,(口山)酮甙,3类8种单体成分(Ⅰ—Ⅷ)。除先前报道过的芒果甙外(Ⅱ),又分离和鉴定了苦龙甙(Ⅲ),当药黄素(Ⅷ),8-O-β-D-吡喃葡萄糖-1,3,5-三羟基(口山)酮(Ⅶ),8-O-[β-D-吡喃木糖-(1→σ)-β-D-吡喃葡萄糖]-1,7-二羟基-3-甲氧基(口山)酮(Ⅵ)4种已知天然化合物。应用化学和光谱分析方法,测定另外3种新(口山)酮甙的结构为:7-O-[α-L-吡喃鼠李糖-(1→2)-β-D-吡喃木糖]-1,8-二羟基-3-甲氧基咄酮(Ⅰ),7-O-β-D-吡喃木糖-1,8-二羟基-3-甲氧基(口山)酮(Ⅳ),3-O-β-D-吡喃葡萄糖-1,8-二羟基-5-甲氧基(口山)酮(Ⅴ)。芒果甙,苦龙甙和7-O-[α-L-吡喃鼠李糖-(1→2)-β-D-吡喃木糖]-1,8-二羟基-3-甲氧基(口山)酮为川西獐牙菜主要甙类成分。有兴趣的是在已发现的龙胆科植物(口山)酮糖甙中,未见(口山)酮木糖甙,(口山)酮鼠李糖-木糖甙的报道。     

滇杠柳的化学成分

从滇杠柳(Periploca forrestii)根茎中分得一个新强心甙元8-羟基杠柳甙元(3β,5β,8β,14β-四羟基-强心甾-20(22)-烯内酯(1),同时还获得杠柳甙元(2),杠柳甙(3),北五加皮甙E(4),胡萝卜甙(5)和熊果酸(6)。它们的化学结构经光谱和化学方法得以确定。     

黑刺菝葜中的甾体皂苷

从黑刺菝葜(Smitax scobinicaulis C.H.Wringh)根茎中再次分离得到2个新的甾体皂苷化合物,经理化、光谱分析及与标准样品对照,鉴定化合物Ⅲ为(25D)螺甾-5-烯-3β,17α,27-三羟基-3-O-β-D-吡喃葡萄糖-(1→4)-O-[α-L-吡喃阿拉伯糖(1→6)]-β-D-吡喃葡萄糖甙。化合物Ⅳ为(25D)螺甾-3β,17α,27-三羟基-3-O-β-D-吡喃葡萄糖-(1→4)-O-[α-L-吡喃阿拉伯糖(1→6)]-β-D-吡喃葡萄糖甙。     

苦绳的一个新甾体成分

从苦绳(Dregea sinensis Hemsl.),和分出一新的甾体成分,Dresigenin A(I),经化学反应及光谱分析证明其结构为12-O-乙酰基-20-O-(2-甲基丁酰基)二氢肉珊瑚甙元[12-O-acetyl-20-O-(2-methylbutyryl)dihydrosarcostin]。     

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.