High density fermentation and activity of a recombinant lumbrokinase (PI239) from Pichia pastoris

A system for the expression of recombinant lumbrokinase (rPI239) was developed in the yeast Pichia pastoris. A total supernatant protein content of 0.174 g/L of high density fermentation broth was obtained. The rPI239 exhibited in vitro fibrinolytic activity. The in vivo activity of rPI239 was measured by prothrombin time, kaolin part thrombin time, thrombin time, and fibrinolytic activity. This work presents the high-density fermentation of rPI239 from P. pastoris and shows that the recombinant protein has similar fibrinolytic activity both in vivo and in vitro.     

A Bipartite Network-based Method for Prediction of Long Non-coding RNA–protein Interactions

As one large class of non-coding RNAs(nc RNAs), long nc RNAs(lncRNAs) have gained considerable attention in recent years. Mutations and dysfunction of lnc RNAs have been implicated in human disorders. Many lnc RNAs exert their effects through interactions with the corresponding RNA-binding proteins. Several computational approaches have been developed, but only few are able to perform the prediction of these interactions from a network-based point of view. Here,we introduce a computational method named lnc RNA–protein bipartite network inference(LPBNI). LPBNI aims to identify potential lnc RNA–interacting proteins, by making full use of the known lnc RNA–protein interactions. Leave-one-out cross validation(LOOCV) test shows that LPBNI significantly outperforms other network-based methods, including random walk(RWR)and protein-based collaborative filtering(Pro CF). Furthermore, a case study was performed to demonstrate the performance of LPBNI using real data in predicting potential lnc RNA–interacting proteins.     

hTRT反义基因转染对人结肠癌细胞生长的抑制作用

利用基因重组技术,hTRT基因反向插入真核表达载体pcDNA3．0,获得重组体pcDRTRT,通过脂质体法导入人结肠癌细胞株SW-111C,获得稳定转染细胞系,即反义细胞,该细胞易脱落,出现明显生长抑制现象;失去叠落生长能力;流式细胞仪(FCM)证实导入反义hTRT后,G0/1期细胞增加,G2M和S期细胞减少,增殖指数(PI)降低;且不能在软琼脂中形成集落;并发现反义细胞中hTRT表达水平明显下降。说明反义hTRT基因体外导入结肠在细胞株SW-111C可以明显降低端粒酶活性,抑制结肠癌细胞的生长、增殖且能使其恶性表型发生逆转。     

基因组数据库简介

本文以北京大学生物信息中心安装的3个国际著名基因组数据库GDB、GenoList和Ensembl为基础,介绍目前常用的基因组数据库,包括这些数据数据库的内容、数据格式、使用方法,以及用于构建上述数据库的数据库管理系统。 Abstract:A brief introduction to the genome databases GDB,GenoList and Ensembl is given.These databases,mirrored and maintained at the Centre of Bioinformatics,Peking University,provide useful information for genome research.     

T-DNA插入水稻群体中卷叶突变体R1-A2的遗传分析

在根癌农杆菌介导的T-DNA(携带有除草剂Basta抗性基因bar和Ds因子)转化中花11水稻群体中,获得了一个叶片发生明显内卷的突变体R1-A。经过连续三代的分离鉴定,获得突变体的纯合株(R1-A2),并与中花11号进行杂交,在调查的36个F_1植株中,全部表现为卷叶,并对Basta除草剂都表现为抗性。在852个F_2单株中,卷叶为645株,正常叶207株,卷叶和正常叶的比例为3:1,其中,卷叶株均对Basta表现抗性,正常叶株均对Basta表现敏感,表明卷叶性状和Basta抗性存在着共分离关系。用扩增Ds因子的引物,对F_2中45个卷叶抗性株进行PCR鉴定,都获得预期长度的Ds因子片段,进一步表明在这些卷叶的植株中都有T-DNA的插入;而30个正常叶敏感株都不能检测到Ds的特征片段。在以卷叶突变(R1-A2)为回交亲本的F_1B_1植株中,全部植株表现卷叶;在以中花11号为回交亲本的F_1B_1植株中,卷叶和正常叶植株的分离比为1:1。上述结果表明该卷叶突变是个显性突变,受一个基因所控制,且该基因的突变与T-DNA的插入有关。     

Superoxide anion burst and taxol production induced by Ce in suspension cultures of Taxus cuspidata

Generation of reactive oxygen species (ROS) induced by Ce⁴⁺ in suspension cultures of Taxus cuspidata was investigated. The burst of superoxide anions (O₂√⁻) occurred rapidly after the addition of Ce⁴⁺ and reached maximum at 4.3 h, while the total level of the cellular reactive oxygen species maintained unchanged. The intracellular superoxide dismutase (SOD) and catalase (CAT) were activated while the intra/extracellular peroxidases (PODs) were inhibited accompanying the O₂√⁻ burst. The pretreatment of the suspension cultures with diphenylene iodonium (DPI), a suicide inhibitor of the NADPH oxidase, blocked the O₂√⁻ burst, inhibiting the cell apoptosis and taxol production induced by Ce⁴⁺. These results show that NADPH oxidase played a key role in O₂√⁻ burst and O₂√⁻ served as a mediator of Ce⁴⁺ for cell apoptosis and taxol production. The pretreatments of the suspension cultures with anthracene-9-carboxylate, an ion-channel blocker, nifedipine, a Ca²⁺-channel blocker, neomycin, a phospholipase C (PLC) inhibitor, or suramin, a G-protein inhibitor, decreased O₂√⁻ burst induced by Ce⁴⁺. It is thus inferred that Ce⁴⁺-induced O₂√⁻ burst, which mediated cell apoptosis and taxol production by activating the ion-channels, PLC, G-proteins and NADPH oxidase.     

人慢性胃炎胃粘膜内胃泌素及其mRNA的表达和意义

目的　探讨慢性胃炎胃粘膜对细胞内胃泌素 (G)及其mRNA的表达和意义。方法　标本均来自活检的胃窦部粘膜组织 ,用免疫细胞化学和原位杂交技术。结果　对照组G细胞及GmRNA阳性细胞数 ,与浅表性胃炎组比较无显著性差异 (P >0 0 5 ) ,而与萎缩性胃炎组比较则有显著性差异 (P <0 0 1) ,不论对照组还是胃炎组的G细胞数量与GmRNA阳性细胞均有平行关系。结论　证明浅表性和萎缩性胃炎的胃泌素基因的转录和蛋白表达功能保存完好 ,因此检测G细胞的数量及GmRNA不仅可以帮助了解胃炎的萎缩程度 ,而且能判断临床疗效。     

Ethanol fermentation with Kluyveromyces marxianus from Jerusalem artichoke grown in salina and irrigated with a mixture of seawater and freshwater

Aims: To study fuel ethanol fermentation with Kluyveromyces marxianus ATCC8554 from Jerusalem artichoke (Helianthus tuberosus) grown in salina and irrigated with a mixture of seawater and freshwater. Methods and Results: The growth and ethanol fermentation of K. marxianus ATCC8554 were studied using inulin as substrate. The activity of inulinase, which attributes to the hydrolysis of inulin, the main carbohydrate in Jerusalem artichoke, was monitored. The optimum temperatures were 38°C for growth and inulinase production, and 35°C for ethanol fermentation. Aeration was not necessary for ethanol fermentation with the K. marxianus from inulin. Then, the fresh Jerusalem artichoke tubers grown in salina and irrigated with 25% and 50% seawater were further examined for ethanol fermentation with the K. marxianus, and a higher ethanol yield was achieved for the Jerusalem artichoke tuber irrigated with 25% seawater. Furthermore, the dry meal of the Jerusalem artichoke tubers irrigated with 25% seawater was examined for ethanol fermentation at three solid concentrations of 200, 225 and 250 g l^?1, and the highest ethanol yield of 0·467, or 91·5% of the theoretical value of 0·511, was achieved for the slurry with a solid concentration of 200 g l^?1. Conclusions: Halophilic Jerusalem artichoke can be used for fuel ethanol production. Significance and Impact of the Study: Halophilic Jerusalem artichoke, not competing with grain crops for arable land, is a sustainable feedstock for fuel ethanol production.     

黄色隐球酵母生产辅酶Q10发酵条件的优化

从黄色隐球酵母L3302提取辅酶Q10,经过氮源、碳源、初始pH、发酵温度等的研究分析,得到最佳的发酵条件。通过最优化实验确定培养基:蔗糖和葡萄糖各1.25g/L;酵母膏和玉米浆各0.3g/L;pH值6.5,温度28℃,接种量5%,装液量为50mL/500mL;生长因子以蛋白水解液为优。按此发酵条件上罐发酵,得到菌体生长量为12.8g/L发酵液,辅酶Q10的产量为1.82mg/100mL发酵液。     

甘蓝型油菜秦优10号杂交种纯度鉴定的SSR引物筛选

为了建立一套快速可靠的油菜杂交种纯度的鉴定方法,本文以秦优10号及其亲本、杂种ZZH2为试验材料,对前人开发的2对SSR引物(7号引物, 9号引物)进行了再次筛选.结果显示,7号引物不但能很好地区别出混入杂交种中的亲本,还能将杂交种子的同母异父组合种子从杂交种中分离出来,能够用于鉴别秦优10号杂交种子的真伪;9号引物能区分出杂交种和母本,但不能区分开杂交种和父本.同时,本试验利用人工制成的秦优10号杂交种标准样(纯度为100%)以及7份大田鉴定不同纯度梯度的杂交种子对7号引物鉴定结果的准确性进行了验证,鉴定结果与大田鉴定结果基本一致.本文结果将为鉴定秦优10号杂交种纯度提供更准确的技术资料.