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.
铈诱导东北红豆杉凋亡细胞蛋白质的双向凝胶电泳分析   总被引:5,自引:2,他引:3  
应用蛋白质双向凝胶电泳方法,研究了Ce^4 诱导悬浮培养红豆杉细胞凋亡过程中蛋白质的表达,分析了凋亡细胞与正常细胞的蛋白质组差异。发现在Ce^4 诱导4d后的凋亡样品中有13个新的蛋白质点出现,而在对照组细胞样品中未检测到,此外,还发现凋亡细胞中有一些蛋白质的含量明显高于对照组。表明Ce^4 诱导的红豆杉细胞凋亡过程中有新蛋白质的合成及原有某些蛋白质量的改变。说明Ce^4 诱导了某些功能蛋白的表达,红豆杉细胞凋亡的发生可能与这些新蛋白质的合成有关。  相似文献   

2.
为了探究培养生长不同时期的红豆杉细胞对Ce4 应答差异的机制,采用West-Blot免疫印迹法考察了1 mmol.L-1Ce4 对培养不同时期的红豆杉细胞的细胞外信号调节蛋白激酶磷酸化(p-ERK-like)的表达变化。结果发现,悬浮培养的红豆杉细胞基础p-ERK-like的表达在整个培养周期中呈"M"型变化,分别在培养第五天和第二十一天出现两个高峰,而培养第十一天达到低谷,仅为参比值的77%。在培养的不同时间点应用Ce4 诱导后,细胞的最大p-ERK-like表达量以及到达最大量所需的时间表现出显著的差异,培养第十一天的细胞经Ce4 诱导后其p-ERK-like表达速率达高峰。结果表明,处于不同培养时期的红豆杉细胞其p-ERK-like表达存在显著差异,这可能是导致不同培养时期细胞对Ce4 产生不同应答效应的一个因素。  相似文献   

3.
镧、铈对红豆杉细胞生长及紫杉醇合成与释放的影响   总被引:35,自引:6,他引:29  
研究镧、铈对东北红豆杉悬浮细胞生长及紫杉醇合成与释放的影响。结果表明,当发酵液中稀土浓度较高时,均能明显改变东北红豆杉细胞的生长模式,使细胞生长的延迟期与对数期缩短,平稳期消失,并于衰亡期出现生物量的周期性振荡;在细胞生长的对数期加入稀土化合物能显著提高东北红豆杉细胞合成与释放紫杉醇的量;在加入稀土化合物的同时,补加碳源,有利于细胞合成紫杉醇。  相似文献   

4.
高效液相色谱法测定红豆杉培养细胞中紫杉醇的含量   总被引:5,自引:0,他引:5  
甘烦远  郑光植  彭丽萍  罗建平 《色谱》1996,14(4):306-307
 采用Spherisorb C_6H_5柱,以甲醇:乙腈:水(2:3:8.5)为流动相,在228nm波长下检测,对3种红豆杉即云南红豆杉(Taxus yunnanensis)、红豆杉(T.chinensis)和欧洲红豆杉(T.baccata)培养细胞中紫杉醇(Taxol)的含量进行了测定。建立了一套简单、快速、准确的测定红豆杉培养细胞中紫杉醇的高效液相色谱方法,最低检出量可达0.5μg。  相似文献   

5.
为了探讨Ce^4+对过氧化氢酶(cAT)构象的影响,以离体的牛肝过氧化氢酶(CAT)为实验材料。用紫外.可见吸收光谱、荧光光谱、CD谱、红外光谱等方法分析Ce^4+作用后CAT构象的变化,发现CAT的构象与Ce^4+的浓度相关,Ce^4+的浓度较低时,CAT的α-螺旋含量增加。β-折叠含量减小;Ce^4+的浓度较高时,结果相反。结果表明,不同浓度的Ce^4+对CAT构象的影响不同。  相似文献   

6.
用高温固相法合成了NaLn(PO3)4:1.0%(原子分数)Ce^3+(Ln=La,Gd)两种粉末发光材料,在合肥国家同步辐射实验室(NSRL)测得两种样品中Ce^3+的真空紫外光谱。根据真空紫外光谱图,得到了两种稀土偏磷酸盐中所掺Ce^3+离子5d轨道的能级分裂图。结合NaLa(PO3)4和NaGd(PO3)4的单晶结构数据,发现随着Ln-O平均键长的减小,Ce^3+离子5d轨道的晶场劈裂(εcfs)、重心位移(εc)和总的红移(total redshilt,D)均增大。根据配体极化模型,计算了两种化合物中掺杂Ce^3+离子的有效平均键长(Reff)和光谱极化率(αsp),发现随着平均键长Rav(Ln—O)变短,Ce^3+离子的光谱极化率(αsp)也随之减小。  相似文献   

7.
用乙酸和葡萄糖作为诱导试剂,研究酿酒酵母(Saccharomyces cerevisiae)凋亡细胞的毛细管电泳特征及凋亡细胞DNA的荧光光谱特征。发现不同的诱导条件,凋亡细胞的形态、DNA片段化特征不同。荧光光谱证实:乙酸能与脱氧核糖核酸链上的特异位点相结合,形成一种新的加合物,从而断裂DNA;而葡萄糖诱导产生的凋亡过程是一种新陈代谢失调促凋过程,发现两者启动细胞凋亡程序的因素不同。  相似文献   

8.
研究Ce4 对悬浮培养南方红豆杉细胞可溶性蛋白和紫杉醇合成的动态影响,Ce4+对可溶性蛋白合成和细胞活力的影响存在“分区和分叉现象,低浓度Ce4 (0.010mmol.L^-1)可显著提高可溶性蛋白的合成强度和细胞活力,高浓度Ce4 (5.00mmol.L^-1)对细胞表现为强伤害作用,适宜浓度Ce4 (1.00mmol.L^-1)在短期内可大幅度提高紫杉醇的合成速度,达到最高积累。  相似文献   

9.
褐藻多糖铈配合物对质粒DNA及牛血清白蛋白的裂解作用   总被引:13,自引:3,他引:10  
以褐藻糖胶、褐藻酸及褐藻演粉为配体,分别与四价的铈(Ce^4 )结合,形成了水溶性的褐藻多糖铈配合物,在生理中性条件下,它们对牛血清白蛋白(BSA)均有一定的裂解作用,但对质粒DNA(Plasmide DNA)仅有褐藻淀粉铈配合物有非常明显的裂解作用。  相似文献   

10.
报道了铈离子及其配合物对人工设计合成的26个碱基的单链寡聚脱氧核糖核酸(ODN)的水解断裂作用,Ce^3 需要有氧气存在的条件下,氧化生成Ce^4 后才能切断ODN。研究了各种条件下Ce^4 与ODN的切断反应,在酸性和弱碱性条件下都能水解切断ODN,在近中性时切断作用最强,随着反应温度的升高,Ce^4 浓度的增大,反应时间的延长,切断反应越来越明显,Ce^4 与氮三乙酸生成配合物以后也能切断ODN,Ce^4 可作为切断ODN的分子剪刀。  相似文献   

11.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

12.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

13.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

14.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

15.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

16.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

17.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

18.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.  相似文献   

19.
20.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  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