不同浓度和梯度的SDS-PAGE胶对双向电泳中蛋白分离的影响

目的：探讨双向电泳中不同浓度和梯度的SDS-PAGE胶对肠道菌蛋白分离效果的影响。方法：制备弗氏2a志贺菌2457T野生株37℃晚期全菌蛋白质样品,进行不同浓度及梯度的SDS-PAGE,研究分离肠道菌蛋白最适宜的SDS-PAGE胶浓度。结果：获得了3个不同浓度（10%、12.5%和15%）的均一胶电泳图谱和3个不同梯度（4%～15%、10%～20%和12%～14%）的电泳图谱,并比较了这些图谱的分离效果;同时,为了分析肠道菌天然表达蛋白的相对分子质量范围,鉴定了8个极端相对分子质量蛋白。结论：对于肠道菌蛋白质的分离来说,12.5%的均一胶或12%～14%的梯度胶较为适宜。     

中国人血清中丙型肝炎病毒聚合酶全长基因的克隆表达及鉴定

构建中国人丙型肝炎病毒(HCV)复制的RNA聚合酶原核表达载体pET30aNS5b,并在大肠杆菌中获得NS5B聚合酶蛋白的高效表达,为建立HCV NS5b聚合酶细胞外分子复制模型的方法创造条件。使用高保真Pfu DNA聚合酶进行反转录及套式PCR扩增,从我国HCV RNA阳性血清中扩增出HCV NS5b RNA多聚酶全基因序列,经BamHI和SalI酶切,将其克隆至同样酶切的pET-30a载体中;转化大肠杆菌BL21,IPTG诱导表达。用抗HCV NS5b单克隆抗体做Western-Blot进行鉴定。结果表明构建了原核表达载体,pET30aNS5bpET30aNS5b明显表达出12-His-NS5b聚合酶蛋白。测序结果表明,与已发表的相关HCV NS5b RNA聚合酶序列比较,其核苷酸和氨基酸的同源性分别在69％-92．7％及88．8％-96．8％之间。在最佳表达条件下,可高效诱导表达融合蛋白(65kDa),最高表达量占菌体蛋白18．9％。Western-Blot结果显示表达蛋白为HCV NS5b酶。HCV聚合酶蛋白全长基因可以成功地克隆在pET-30a载体上并有效表达出目的蛋白,为研究建立HCV NS5b聚合酶细胞外分子复制模型奠定了基础。     

家蚕细胞凋亡相关基因BmICAD的克隆、序列和功能分析及其在精巢中特异表达的初步研究

DREP-1基因在果蝇的细胞凋亡过程中对DNA的降解有重要调控作用。本研究将该基因序 列在家蚕EST数据库中进行同源性检索,把检索到的EST序列进行电子延伸和克隆重叠群拼接,根据拼接结果设计引物进行PCR扩增并克隆测序验证,首次成功克隆了家蚕第一个ICAD基因BmICAD的cDNA： 该cDNA全长844 bp,ORF长522 bp, 编码含有174个氨基酸的蛋白;预测分子量为19.6kD,等电点为4.23,所编码蛋白与果蝇DREP-1的一致性(identity)为36%;虽然Northern印记杂交未检测到信号,但是RT-PCR结果显示,该基因在精巢中特异表达。     

The efficacy of a novel insecticidal protein, Allium sativum leaf lectin (ASAL), against homopteran insects monitored in transgenic tobacco

The homopteran group of polyphagous sucking insect pests causes severe damage to many economically important plants including tobacco. Allium sativum leaf lectin (ASAL), a mannose-binding 25-kDa homodimeric protein, has recently been found to be antagonistic to various sucking insects in the homopteran group through artificial diet bioassay experiments. The present study describes, for the first time, the expression of the ASAL coding sequence under the control of the cauliflower mosaic virus (CaMV) 35S promoter in tobacco by Agrobacterium-mediated transformation technology. Molecular analyses demonstrated the integration of the chimeric ASAL gene in tobacco and its inheritance in the progeny plants. Western blot analysis followed by enzyme-linked immunosorbent assay (ELISA) determined the level of ASAL expression in different lines to be in the range of approximately 0.68%-2% of total soluble plant protein. An in planta bioassay conducted with Myzus persicae, peach potato aphid (a devastating pest of tobacco and many other important plants), revealed that the percentage of insect survival decreased significantly to 16%-20% in T0 plants and T1 progeny, whilst approximately 75% of insects survived on untransformed tobacco plants after 144 h of incubation. Ligand analyses of insect brush border membrane vesicle receptors and expressed ASAL in transgenic tobacco showed that the expressed ASAL binds to the aphid gut receptor in the same manner as native ASAL, pointing to the fact that ASAL maintains the biochemical characteristics even in the transgenic situation. These findings in a model plant open up the possibility of expressing the novel ASAL gene in a wide range of crop plants susceptible to various sap-sucking insects.     

A novel polymorphic CAAT/enhancer-binding protein beta element in the FasL gene promoter alters Fas ligand expression: a candidate background gene in African American systemic lupus erythematosus patients

A single-nucleotide polymorphism (SNP), identified at nucleotide position -844 in the 5' promoter of the FasL gene, lies within a putative binding motif for CAAT/enhancer-binding protein beta (C/EBPbeta). Electrophoretic mobility shift and supershift assays confirmed that this element binds specifically to C/EBPbeta and demonstrated that the two alleles of this element have different affinities for C/EBPbeta. In luciferase reporter assays, the -844C genotype had twice the basal activity of the -844T construct, and basal expression of Fas ligand (FasL) on peripheral blood fibrocytes was also significantly higher in -844C than in -844T homozygous donors. FasL is located on human chromosome 1q23, a region that shows linkage to the systemic lupus autoimmune phenotype. Analysis of 211 African American systemic lupus erythematosus patients revealed enrichment of the -844C homozygous genotype in these systemic lupus erythematosus patients compared with 150 ethnically matched normal controls (p = 0.024). The -844C homozygous genotype may lead to the increased expression of FasL, to altered FasL-mediated signaling in lymphocytes, and to enhanced risk for autoimmunity. This functionally significant SNP demonstrates the potential importance of SNPs in regulatory regions and suggests that differences in the regulation of FasL expression may contribute to the development of the autoimmune phenotype.     

白细胞介素—2—绿脓杆菌外毒素融合蛋白的分高纯化及其复性研究

表达的白细胞介素－２－绿脓杆菌外毒素（ＩＬ－２－ＰＥ）融合蛋白以包含体形式存在于宿主菌中,为分离纯化表达产物提供了方便,但因需进行复性,也增加了后处理的难度．我们采用４ｍｏｌ／Ｌ尿素、０．５％ＴｒｉｔｏｎＸ－１００的１×ＰＢＳ洗涤包含体两遍,再经ＳｅｐｈａｃｒｙｌＳ－３００分子筛及ＤＥＡＥ－ＳｅｐｈａｒｏｓｅＦＦ阴离子交换柱层析后,获得的融合蛋白纯度可达９０％～９５％。此外,我们从ＧＳＳＧ浓度、Ｌ－精氨酸浓度、复性蛋白质的起始浓度、复性液的ｐＨ值、复性温度及复性时间等参数入手,系统地研究了融合蛋白的复性条件,探索到了ＩＬ－２－ＭＥ４０和ＩＬ－２－ＰＥ６６４Ｇｌｕ融合蛋白复性的最适条件。     

我国生物医药企业发展建议

近年来,国外生物医药产业发展迅速,在发达国家,生物医药产品在药品市场中已占有了重要地位,哺乳动物细胞表达的产品已经占据生物医药的主流地位。相比之下,我国生物医药品种主要采用简单的大肠杆菌、酵母表达技术,技术难度较高的哺乳动物细胞药品与国外差距显著,因此,哺乳动物表达的生物药品将成为国内生物医药企业的重要发展机会。多年来,鉴于我国从发达国家获得生物技术转让少,国内生物医药发展需立足于自主研发,建立高效的研发技术平台,选择合适的开发项目,促进企业的发展。     

东亚飞蝗UBX结构域包含蛋白基因 LmUBX2 的克隆和表达分析

【目的】UBX结构域包含蛋白是p97/CDC48的辅助因子。p97在泛素化相关的多种细胞过程中起着重要的作用,如依赖泛素 蛋白酶体系统的蛋白质降解和同型膜融合等。本研究旨在克隆东亚飞蝗 Locusta migratoria manilensis (Meyen)的UBX结构域包含蛋白基因,分析其组织和发育表达格局,为进一步研究UBX结构域包含蛋白基因的功能奠定基础。【方法】通过分析东亚飞蝗的转录组数据克隆UBX结构域包含蛋白基因,采用实时定量PCR技术分析该基因在不同发育时期和成虫不同组织中的表达水平。【结果】克隆到东亚飞蝗的一个UBX结构域包含蛋白基因,命名为 LmUBX2。 LmUBX2 开放阅读框长1 020 bp,编码399个氨基酸,预测分子量和等电点分别为37.8 kDa和6.03,与其他UBX结构域包含蛋白的氨基酸一致性为37%~64%,N端和C端分别有一个保守的UBA结构域和UBX结构域。序列比较和系统发育分析发现 LmUBX2 属于SAKS1亚家族。定量分析发现,LmUBX2 在整个生命周期中都有表达,但成虫期的表达水平最高;在检测的所有组织中都有表达,但在精巢和卵巢中表达水平最高。【结论】研究结果说明 LmUBX2 可能参与东亚飞蝗多种生理过程,尤其可能与东亚飞蝗的生殖有关,但还需深入研究。     

Mismatch Repair Gene MLH3 Pro844Leu and Thr942Ile Polymorphisms and the Susceptibility to Cervical Carcinoma and HPV Infection: A Case-Control Study in a Chinese Population

To investigate the association between MLH3 Pro844Leu, Thr942Ile polymorphisms and potential linkage with the risk of cervical carcinoma and potential effect on protein function, we carried out a case-control study with 400 cervical squamous cell carcinoma, 400 CIN3 and 1200 normal controls in a Chinese population. The results showed that there was an increased risk of cervical carcinoma and CIN3 associated with the genotype 844CT [OR 2.17 (1.61–2.94); P<0.001; OR 1.49 (1.08–2.07), P 0.017, respectively] and a decreased risk with the 942CT genotype [OR 0.56 (0.38–0.82); P<0.001; OR 0.37 (0.24–0.58), P<0.001, respectively]. Most 844CT genotypes were linkage CT(844)-CC(942), which increased the risk of cervical carcinoma and CIN3 [77/83, OR 2.04 (1.48–2.80), P<0.001; 55/61, OR 1.46 (1.03–2.06), P 0.035, respectively]. Most 942CT were linkage CC(844)-CT(942), which decreased the risk of cervical carcinoma [29/35, OR 0.60 (0.40–0.91); P 0.017; 18/24, OR 0.33 (0.20–0.55), P<0.001, respectively]. In some grouping, the 844CT and 942CT were further enriched; especially HR-HPV-positive subjects both in the CIN3 and the cervical carcinoma, the 844CT had greater enrichment. These results included that CT(844)-CC(942) was associated with a high risk of cervical carcinoma and CIN3, and the CC(844)-CT(942) decreased the risk. The 844CT had a higher level of enrichment in HR-HPV positive individuals, which is probably related to HR-HPV susceptibility. There was no significant difference of the MLH3 mRNA expression and these two amino acid substitutions did not impact on the protein function.