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〕。     

云南匙羹藤的化学成分

从云南匙羹藤(Gymnema yunnanense Tsiang)的粗甙酸水解产物中分离得到6个C_(21)甾体甙元。其中一个新甙元,命名为吉马甙元(gymnemarsgenin),经光谱数据和化学反应证明其结构为12-β-氧-苯甲酰-20-氧-肉桂珊瑚甙元。     

白首乌的化学成分

白首乌(Cynanchum auriculatum Roylc ex Wight),又称耳叶牛皮消,飞来鹤等,系萝蘼科鹅绒藤属植物,是常用中药,具有养血益肝,固肾益精,乌须黑发和延年益寿等作用。据文献报道其含有较高的磷脂类成分和C_(21)甾体酯甙。对其临床药理研究表明白首乌总磷酯可以明显提高正常小鼠外周血T淋巴细胞的数量和促进淋巴细胞的转化,其C_(21)甾体酯甙对环磷酰胺引起的免疫受抑小鼠有一定的调整作用。但有关C_(21)甾体酯甙成分的化学结构未见报道,我们首次对白首乌进行了化学研究,从其粗甙的酸水解产物分离得到了四个C_(21)甾体酯基甙元,经光谱测定和化学反应确定其结构分别为加加明(gagamine 1),告达庭(caudatin 2),萝摩甙元(metaplexigenin 3),凯底甙元(kidjoranin 4)。有关其配糖体的研究工作将另文发表。     

牛奶菜属植物化学成分研究进展

萝藦科牛奶菜属植物全世界约100种,中国产22种5变种,化学成分主要包括C21甾体类、三萜类和环醇类等.本文综述了牛奶菜属植物化学成分的研究进展,为该属植物的进一步研究开发提供参考.     

苦绳甙元的结构

从苦绳[Dregea sinensis var.corrugeta(Schneid)Tsiang et P.T.Li]的根茎中分得一个新的 C_(21)-甾体甙元,命名为苦绳甙元(dersgenin)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-12-β-O-苯甲酰基-20-羟基娠烷(C/Dcis 5α-H、3β、8β、14β、17β tetrahydroxyl-12-β-O-benzoyl-20-hydroxyl-pregnane)。     

通光藤甙元甲的化学结构

通光藤[Marsdenia tenacissima(Roxb.)Wight et Arn.]为云南民间抗癌药用植物。从其藤茎提取的粗甙经水解、皂化后得到一个新的主要甙元,称通光藤甙元甲(tenacigenin A)。通光藤甙元甲分子式 C_(21)H_(32)O_5,熔点255—260℃,属 C_(21)-甾体化合物,能用常法制得二乙酰化合物(Ⅲ),三乙酰化物(Ⅳ)需在剧烈条件下才能得到。三个羟基中有两个可被氧化成六元环酮(Ⅵ)。另两个氧原子则以环氧的形式存在。通光藤甙元甲用醋酐和对甲苯磺酸于100℃加热30小时后得到3β、12β、14β-三乙酰-5α-甾烷-7(8)、9(11)-二烯-20-酮(Ⅸ),后者用铂黑在醋酸中氢化得(Ⅹ)。据上述化学反应和红外光谱、紫外光谱、核磁共振谱及质谱数据,作者提出通光藤甙元甲的结构为(Ⅰ)。     

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)。     

青叶胆植物中的红白金花内酯和青叶胆内酯的结构

本文报告龙胆科獐牙菜属植物青叶胆(Swertia mileensis T.N.Ho et W.L.Shih)中分到的两个微量内酯成分Ⅰ和Ⅱ。经UV.~1H NMR.~(13)C NMR.MS.证明Ⅰ是红白金花内酯(erythrocentaurin),Ⅱ是一新化合物,命名为青叶胆内酯(swermirin)。探讨了青叶胆内酯和獐牙菜甙(sweroside)以及红白金花内酯之间的关系。认为青叶胆内酯是獐牙菜甙,獐牙菜苦甙(swertiamarin)的酶解分子重排游离甙元。此外还讨论了青叶胆内酯部分结构C_7、C_8、C_(10)碳核及与其相连氢核和甲基偏向高场的原因。     

云南产萝藦科牛奶菜属一新种

裂冠牛奶菜新种图1裂冠牛奶菜组,新组Marsdenia incisa P.T.Li et Y.H.Li,sp.nov.Fig.1.Sect.Incisae P.T.Li et Y.H.Li,sect.nov.Specis M.yaungpienensi Tsiang et P.T.Li similis,sed bracteis bracteo-lisque majoribus foliiformibus,calycis segmentis corollis duplo longioribis,corollis flavidis extus hispidis intus glabris,lobis apice incisis,stigmatibusincludentibus differt.     

大理白前的化学成分

从大理白前(Cynanchum forrestii Schltr.)中分离得到2个C_(21)甾体甙,其中一个新甙,命名为大理白前甙A(cynaforroside—A,Ⅰ)。经光谱分析和化学反应,证明(Ⅰ)的结构为芫花白前甙元C 3-氧-α-L-加拿大麻吡喃基-(1→4)-β-L-加拿大麻吡喃基-(1→4)-β-D-夹竹桃吡喃甙(glaucogenin C 3-O-α-L-cymaropyranosyl-(1→4)-β-L-cymaropyranosyl-(1→4)-β-D-oleandropyranoside)     

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.