基于PiggyBac转座系统的低溢漏诱导型Tet-On过表达体系的建立及应用

为避免诱导基因稳定表达的Tet-On诱导表达系统溢漏表达,实现简便且高效的外源基因稳定诱导表达, 本研究拟在Tet-On调控的转录水平基础上,将基于稳定配体Shield-1的不稳定结构域FK506结合蛋白引入目的基因的N端,从蛋白水平控制其本底表达水平.为验证该系统的效果,本研究以荧光蛋白TdTomato为报告基因,经流式分析结果证明优化后的体系较原体系的溢漏表达在蛋白水平上降低7倍左右.将该系统应用于基于小鼠胚胎干细胞的体外牙向分化模型,在诱导因子Dox和稳定配体Shield-1的协同作用下,诱导表达牙齿发育相关转录因子Hand2提高了牙向分化诱导的完成度.     

Morphological,biochemical and molecular changes during ectomycorrhiza development

Summary An ectomycorrhiza, a specialized root organ, is the result of a complex interaction leading to a finely-tuned symbiosis between a plant and a compatible ectomycorrhizal fungus. Ultrastructural observations combined with cytochemical and biochemical studies reveal that structural and metabolic changes in the symbiont cells lead to the final phenotype of the active ectomycorrhiza. In the present review these changes are interpreted as changes in gene expression and discussed within the context of ectomycorrhiza development. Recent genetic data indicate that the continued vegetative growth of the ectomycorrhizal hyphae and the root tissues, and their ability to switch to symbiotic organ formation, is basically controlled by developmentally critical genes. The activity of these symbiotic genes during the differentiation of ectomycorrhizas is associated with extensive changes in the concentration of particular polypeptides and protein biosynthesis. The present state of knowledge about the developmental biology of ectomycorrhizas allows only speculation about the events during their development.Puisant mes forces aux sources des galaxies En buvant la sève des arbres M. Jonasz     

论明清石湾陶艺的美学特色

明清是石湾陶艺创作风格、艺术特色的奠基时期。明清石湾陶艺注重表现,富有生活气息,简约质朴,豪放自然,尤其在人物眼神与衣纹的刻划、“素胎烧制”等艺术表现技巧方面所作出的探索,终经后来历代艺人的发扬光大,已成为今天石湾陶艺所特有的“有意味的形式”,并展示出强烈的艺术魅力。     

Cloning, construction of prokaryotic expression vector and expression ofEscherichia coli cytosine deaminase gene

Cytosine deaminase gene ofEscherichia coli strain H-30 was cloned, and its initiation codon of ‘GTG’ was mutated to ‘ATG’ by PCR. Prokaryotic recombinant expression vector pBV220-CD was constructed. Clone with high enzyme activity were selected by detecting their specific activity of cytosine deaminase. 5-FC(5-FC, 5-fluorocytosine) could induce the lethal toxicity to cells containing active CD gene. DNA sequence analysis indicated that there were 16 altered bases and 5 of them resulted in the alteration of amino acids in predicted peptide by comparing DNA sequence of the clone H-30-CD-11 with high enzyme activity with CD gene reported in Gene Bank.     

Cloning and expression of the vp39 gene ofBombyx mori nuclear polyhedrosis virus inE. coli

The nuclear capsid protein gene (vp39) ofBombyx mori nuclear polyhedrosis virus (BmNPV) was amplified successfully by PCR technique and inserted into pGEM 3zf(+). The 5′ and 3′ terminal area of the amplified vp39 gene were sequenced with silver-staining dideoxy method. Bmvp39 gene was sub-cloned into the expression vector pRSET-A, and transformed intoE. coli BL21. This gene was highly expressed by IPTG induction. SDS-PAGE analysis showed that the expressed protein is about 38 kd, and the expressed amount reached maxium in 4 h with IPTG induction. Supported by the National Natural science Foundation of China and the Doctoral Foundation of Edn carto Committee Liu Deli: born in 1954, Doctoral Candidate from Huazhong Normal University To whom correspondence should be addressed: (027-7882712-2938)     

Construction of High Level Expression Cell Lines of Erythropoietin *

Ｅｒｙｔｈｒｏｐｏｉｅｔｉｎ（ＥＰＯ）ｉｓｏｎｅｏｆｔｈｅｍｏｓｔｉｍｐｏｒｔａｎｔｒｅｇｕｌａｔｏｒｙｆａｃｔｏｒｓｄｕｒｉｎｇｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｍａｍｍａｌｉａｎｅｒｙｔｈｒｏｃｙｔｅ,ａｃｔｉｎｇｍａｉｎｌｙｏｎｔｈｅｅｒｙｔｈｒ...     

外源基因（bar）在转基因燕麦（AvenasativaL.）后代中的遗传与表达

通过微弹轰击获得的含有ｂａｒ基因的转基因燕麦植株自交产生转基因后代。利用ＰＣＲ方法检测ｂａｒ基因在后代中的传递情况。     

耐热碱性磷酸酯酶基因的亚克隆及其在大肠杆菌中的表达

根据耐热碱磷酸酯酶基因的酶切图谱和ＤＮＡ序列,分别在基因的起始密友子和终止密码子设计２个突变引物。引物的５‘端分别带有ＮｄｅⅠ和ＢａｍＨⅠ酶切全点。通过ＰＣＲ从质粒ｐＴＡＰ１１８Ｂ中扩增获得了ＦＤ－ＴＡＰ基因的全序列。经过酶切将基因亚克隆于高达载体ｐＪＬＡ５０３。     

大肠杆菌编码区5′端碱基的统计分析

统计了大肠杆菌１２８８个编码序列开始的３３个碱基位点（１１个密码子）上各碱基出现的概率,发现第２、第３密码子各位点上的碱基概率分布与其它密码子上的碱基分布概率不一样;碱基Ｇ和Ｔ出现的概率从第４个密码子后呈现明显的３周期分布．我们还研究了这些位点上的碱基概率分布与基因表达水平的关系,发现高表达基因和低表达基因在第２、第３密码子各位点上,其各种碱基的概率分布是有区别的;高表达基因碱基Ｇ和Ｔ的概率分布３周期性更明显．