A New Taxane Diterpenoid from the Seeds of Taxus yunnanensis

Plant from the genus of Taxus are a rich source of biologically active diterpennodsbelonging to the unique structural family of taxoids'. Although more than 300 taxoidswere isolated from yew tree', new taxoids still were isolated. In our continuing studieson the yew tree, we have previously isolated several new taxoids from seeds of theChinese yew, Taxus chinensiS var mairei. T yunnanensiS, and Japanese yew, TCuspidata'-'. Further investigation on the extract of the seeds of T yunnanensis …     

Synthesis of novel thiol taxoids based on the 7,10-di-(2,2,2-trichloroethyloxycarbonyl)-10-deacetylbaccatin III: both the syn and anti 10-deacetyl-2′-deoxy-2′-mercaptopaclitaxels

Two new kinds of docetaxel compound, with a mercapto group instead of the hydroxyl on the C13 side chain (both syn and anti), via the 7,10-di-(2,2,2-trichloroethyloxycarbonyl)-10-deacetylbaccatin III route, were synthesized. The uses of trans and cis oxazoline compounds, and their stereoselective ring-opening reactions with thiolacetic acid, were proved to be key steps.     

美国赭纤虫纤毛器微管胞器的形态和形态发生

应用荧光紫衫醇(FLUTAX)标记异毛类纤毛虫美国赭纤虫(Blepharisma americanum)纤毛器微管胞器,结果显示：细胞形态发生中,后仔虫口器微管在皮层口围带后第一列体纤毛位置发生,前仔虫口器微管在老口围带位置形成;新的体纤毛在各个老体纤毛列中部两纤毛基体之间发生,此后新、老体纤毛共同组成为新仔虫的体纤毛...     

一种新型的紫杉烷生物素共轭物的制备

生物素与肿瘤细胞表面的生物素受体结合,通过受体介导的内吞作用将共轭物摄入细胞内,二硫键在肿瘤细胞中能够开链,释放出活性物质,实现靶向性给药,从而大大降低传统化疗药物因缺乏对肿瘤细胞的选择性而引起的毒副作用。用巯基置换的方式,合成含有二硫键的连接链;用将羧酸基团转化为酰肼基团的方法,将生物素转化为生物素酰肼;选用具有抗多药耐药性的含氟紫杉烷SB-T-12854作为细胞毒分子;通过含有二硫键的连接链将含氟紫杉烷化合物SB-T-12854与生物素酰肼进行偶连,形成一种新型的紫杉烷生物素共轭物。     

南方红豆杉紫杉烷7β-羟基化酶基因全长序列的克隆和进化分析

 从南方红豆杉Taxus wallichiana var.mairei的新鲜嫩叶中提取基因组DNA作为模板,利用三组特异引物进行PCR扩增,然后克隆测序得到紫杉烷7β-羟基化酶的基因全长。该基因编码区起始密码子为ATG,终止密码子为TGA,全长1 692 bp;碱基组成为490 A (29.0%),351 C (20.7%),362 G (21.4%)和489 T (28.9%)。将紫杉烷7β-羟基化酶基因全长序列与细胞色素P450基因家族的其它三个成员进行比对,发现它与紫杉烷2α-羟基化酶基因、紫杉烷10β-羟基化酶基因及紫杉烷13α-羟基化酶基因的一致性分别为74%、68%及76%。它们的外显子和内含子的连接区均具保守的GT-AG结构,内含子区的变异性明显高于外显子区。进一步以红豆杉属的13个紫杉烷羟基化酶基因家族成员为对象,利用位点间可变ω(非同义替换率dN和同义替换率dS的比值) 模型对该基因家族的适应性进化进行分析。分支模型、位点模型以及分支－位点模型的分析表明：紫杉烷羟基化酶基因家族的少数分支处于正选择压力下(ω>1),但未检测到正选择位点;而绝大部分位点受强烈的负选择作用(ω<1)。