首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
“最大持续产量”及其确定方法的探讨   总被引:1,自引:0,他引:1  
我国《中药材生产质量管理规范》(GAP)的起草工作已正式启动 ,其目的是通过规范中药材生产过程 ,以保证药材达到规定的质量标准。由于药材生产在我国品种繁多 ,且 80 %左右为野生药材 ,因此在规范中药材生产的同时 ,必须保护和发展野生中药材资源。为此 ,在草拟的《中药材生产质量管理规范 (GAP)指导原则 (A)植物药材》的文件中 ,明确提出“调控野生药材的采集强度 ,坚持最大持续产量 (maximumsustainedyield ,MSY)原则 ,以保护野生药材资源 ,并进一步促进药用植物种植业和动物养殖业的发展 ,保证中药资源的…  相似文献   

2.
巴戟天自古用为强壮药 ,系茜草科植物巴戟天MorindaofficinalisHow .的干燥根。历年版《中国药典》均有收载 ,具有补肾阳 ,强筋骨 ,祛风湿等功效。因其临床需求量大 ,来源紧缺 ,近些年来常见其它品种混充入药 ,本文采用薄层色谱法对其进行了鉴定。1 药材来源巴戟天MorindaofficinalisHow来自苏州市药材站 ,越南巴戟天 (来源不详 )来自安徽亳州 ,虎刺Damnacanthusindicus (L .)Gaertn .、羊角藤MouindaumbellataL .、假巴戟Morindashung…  相似文献   

3.
紫杉醇 (Taxol)是一种新型的抗癌药物。由于紫杉醇在红豆杉属 (TaxusL .)植物中的含量很低 ,而且运用植物细胞培养技术生产紫杉醇仍处实验阶段 ,因此 ,对于紫杉醇含量甚微的样品 ,寻找一种精确、灵敏、快速的检测方法就显得尤为重要。本实验采用改进的HPLC法对南方红豆杉〔Taxuschinensisvar.mairei (Leme啨etL啨vl.)ChengetL .K .Fu〕枝和叶 ,以及中国红豆杉〔Taxuschinensis (Pilger)Rehd .〕细胞培养物中的紫杉醇含量进行了测定。1 实验方法1 1 实…  相似文献   

4.
齿裂蒲儿根 新种 图 1SinoseneciodenticulatusJ.Q .Liu ,sp .nov .Fig.1HabituS .euosmo (Hand . Mazz.)B .Nord .etS .cortusifolio (Hand . Mazz.)B .Nord .sim ilis,  相似文献   

5.
濒危植物矮牡丹的生态位研究   总被引:26,自引:2,他引:24       下载免费PDF全文
矮牡丹 (PaenoniasuffruticosaAndr .var .spontaneaRehd .)属毛茛科 (Ranunculaceae)芍药属植物[1] ,为我国特有种 ,仅分布于山西稷山马家沟、永济水峪口 ,陕西延安万花山、华阴二仙桥等地 ,其花具有一定的观赏价值 ,根作“丹皮”入药 ,既是宝贵的花卉种质资源 ,又是优良的药材资源 ;且为栽培牡丹的原始种之一[2 ] 。由于自然植被的破坏和 2 0世纪 60年代的大量采掘 ,致使矮牡丹分布范围日益缩小。目前已被列为国家三级保护植物。生态位的概念自Grinell的“生物在栖息地所占…  相似文献   

6.
小麦醇溶蛋白盒结合因子基因启动子序列   总被引:2,自引:0,他引:2  
1 Source Thesequencewasdeterminedfromare versePCRproduct,whichwasligatedtopMD1 8 Tvector(TaKaRaBiotechnologyCo .) ,fromnucleargenomicD  相似文献   

7.
保护生物学是近15年来随着人们对生物多样性认识的提高而迅速发展起来的一门多学科交叉学科。保护生物学有3大目标:第1是研究并描述生物多样性;第2是了解人类活动对物种、群落及生态系统的影响;第3是发展实际可行的多学科协调,以达到保护及恢复生物多样性的目的。《保护生物学入门》(第2版)由美国波士顿大学生物系教授RichardB.Primack编著,由SinauerAssociates,Inc于2000年在美国麻省出版。该书全方位地及时向读者简明介绍保护生物学领域中的许多重要问题,比如可持续性发展,保护区的设计,以及濒危物种…  相似文献   

8.
在总结中国植物园发展历史及当前国际植物园发展趋势的基础上,论述了中国植物园面对对世纪所必须重视的5个方面。(1)植物园整体质量和特征化,作者列举了10个方面的差距。(2)药用植物的栽培、利用和保护。从药用植物分类学研究,有效成分的分析及动态研究,药用植物栽培化和“地道药材”问题4个方面论述植物园的优势和潜力。阐明了“栽培化”的涵义。(3)引种和物种保护,指出广泛引种的重要性和重点种类迁地保护的必要性,并首次提出了“濒危生境”这个术语及其概念。指出了未来引种理论研究的方向及其对农业生产的意义。(4)活植物收集圃信息系统。(5)科普教育。作者认为,虽然不少植物园目前还面临着或多或少的困难,但就整体而言,未来的10年将是植物园继续较大发展的10年。  相似文献   

9.
云南东南部秋海棠属侧膜组一新种   总被引:2,自引:0,他引:2       下载免费PDF全文
吴氏秋海棠 新种 (侧膜组 ) 图 1BegoniazhengyianaY .M .Shui,sp .nov .(sect.ColoecentrumIrmsch .) ,Fig .1SpeciessimilisB .luzhaiensiKu ,quaefoliorumlaminisi  相似文献   

10.
小麦高分子量麦谷蛋白亚基5基因序列   总被引:1,自引:0,他引:1  
1 Source ThesequencewasdeterminedfromaPCRproduct,whichwasligatedtopMD1 8 Tvector(TaKaRaBiotechnologyCo.) ,fromnucleargenomicDNAof“che  相似文献   

11.
To extend the potential of 5′-noraristeromycin (and its enantiomer) as potential antiviral candidates, the enantiomers of the carbocyclic 5′-nor derivatives of 5′-methylthio-5′-deoxyadenosine and 5′-phenylthio-5′-deoxyadenosine have been synthesized and evaluated. None of the compounds showed meaningful antiviral activity.  相似文献   

12.
Abstract

First experimental evidence is herein reported supporting the earlier quantum chemical calculations that 5′-Punne-pyrimiidine-3′ 3′ -Pyrimidine-Punne-5 stack is more stable than 5′-Pyrimiidine-Punne-3′ 3′-Punne-Pyrimidine-5′.  相似文献   

13.
14.
Abstract

Phosphorylation of 2′-0-acetyl-3′-trifluoroacetamido-3′-deoxy-N2-palmitoylguanosine with N-morpholino-O, O-bis(1-benzotriazolyl)phos-phate gives a 5′-phosphotriester. Removal of the benzotriazolyl group and addition of pyrophosphoric acid gave, after deblocking all protecting groups, GTP(3′NH2).  相似文献   

15.
Abstract

In order to obtain a high degree of rigidity within the sugar moiety of nucleosides, some bicyclic pyrimidine nucleoside analogues where synthesized starting from cyclopentanone. The C-4′-substituent is fused to the C-3′-position via a propylene to give a [3.3.0]-bicyclic ring system.  相似文献   

16.
17.
Abstract

Two nucleoside analogs were synthesized to test the ribose conformational and electronic effects on phosphate hydrolysis at the 3′ position. It was found that under alkaline conditions, a 2′-fluoro-nucleoside (C3′-endo) resulted in a phosphate degradation that was ten times faster than the 2′-deoxynucleoside analog (C2′-endo). In addition to kinetic differences, product distributions will be presented.  相似文献   

18.
Abstract

A series of 3′-N-substituted 3′-amino-3′-deoxythymidine derivatives with alkyl, alkenyl and alkylaryl substituents was synthesized by two methods. The first method involved the reaction of 1-(2,3-dideoxy-3-0-mesyl-5-0-trityl-β-D-threo-pentofuranosyl)thymine with an appropriate amine. In the second method, 3′-amino-5′-0-trityl-3′-deoxy-thymidine served as a synthetic precursor which was reacted with an appropiate aldehyde or ketone followed by sodium borohydride reduction. An improved synthesis of 3′-amino-3′-deoxythymidine from 3′ -azido-5′-0-trityl-3′-deoxythymidine using sodium borohydride was also described.  相似文献   

19.
Abstract

Resistant variants were selected in vitro against two novel nucleoside analogues, (+) dOTC and (-) dOTFC using the HIV-1 molecular clone HXB2D. The variants obtained displayed 6.5-fold and 10-fold resistance to these compounds, respectively. Cloning and sequencing of the RT genes of the selected viruses identified two mutations, M184I for (+) dOTC and M184V for (-) dOTFC. Results with mutated recombinant clones of HXB2D confirmed the importance of these mutations in MT-4 cells. The resistance profiles of clinical samples with wild-type or 3TC-resistant phenotypes were also studied; low to moderate levels of cross-resistance were observed against the novel compounds.  相似文献   

20.
Abstract

The 5′-O-(4,4′-dimethoxytrityl) and 5′-O-(tert-butyldimethylsilyl) derivatives of 2′-,3′-O-thiocarbonyl-6-azauridine and 2′,3′-O-thiocarbonyl-5-chlorouridine were synthesized from the parent nucleosides by reaction with 4, 4′-dimethoxytrityl chloride and tert-butyldimethylsilyl chloride, respectively, followed by treatment with 1,1′-thiocarbonyldiimidazole. Introduction of a 2′-,3′-double bond into the sugar ring by reaction of the 5′-protected 2′-,3′-O-thionocarbonates with 1, 3-dimethyl-2-phenyl-1, 3, 2-diazaphospholidiine was unsuccessful, but could be accomplished satisfactorily with trimethyl phosphite. Reactions were generally more successful with the 5′-silylated than with the 5′-tritylated nucleosides. Formation of 2′-,3′-O-thiocarbonyl derivatives proceeded in higher yield with 5′-protected 6-azauridines than with the corresponding 5-chlorouridines because of the propensity of the latter to form 2,2′-anhydro derivatives. In the reaction of 5′-O-(tert-butyldimethylsilyl)-2′-,3′-O-thiocarbonyl-6-azauridine with trimethyl phosphite, introduction of the double bond was accompanied by N3-methylation. However this side reaction was not a problem with 5′-O-(tert-butyldimethylsilyl)-2′-, 3′-O-thioarbonyl-5-chlorouridine. Treatment of 5′-O-(tert-butyldimethylsilyl)-2′-, 3′-didehydro-2′-,3′-dideoxy-6-azauridine with tetrabutylammonium fluoride followed by hydrogenation afforded 2′-,3′-dideoxy-6-azauridine. Deprotection of 5′-O-(tert-butyldimethylsilyl)-2′-, 3′-didehydro-2′-,3′-dideoxy-5-chlorouridine yielded 2′-,3′-didehydro-2′-,3′-dide-oxy-5-chlorouridine.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号