PRMT2剪接体在乳腺癌细胞株中的表达

目的 检测并观察蛋白质精氨酸甲基转移酶2(protein arginine methyltransferase 2,PRMT2)及其新的剪接体PRMT2α、PRMT2β、PRMT2γ在雌激素受体α(estrogen receptor α,ERα)阳性和ERα阴性乳腺癌细胞株中的表达情况.方法 提取ERα阳性乳腺癌细胞株(ZR-75-1、BT474、T47D、MCF-7)和ERα阴性的乳腺癌细胞株(MDA-MB-453、SK-BR-3、MDA-MB-231)总RNA并用RT-PCR方法检测PRMT2及其新剪接体mRNA的表达,采用内对照甘油醛-3-磷酸脱氢酶(glyceraldehyde-3-phosphate dehydrogenase,GAPDH)同时进行相对定量以进行校正.结果 不同乳腺癌细胞株中均可检测到PRMT2及其新剪接体的表达,在ERα阳性乳腺癌细胞株(ZR-75-1、BT474、T47D、MCF-7)中表达均较高,而在ERα阴性的乳腺癌细胞株(MDA-MB-453、SK-BR-3、MDA-MB-231)中表达均较低.结论 PRMT2与PR MT2α 、PRMT2β、PRMT2γ基因在不同乳腺癌细胞株中存在差异表达,在ERα阴性乳腺癌细胞中低于ERα阳性乳腺癌细胞,PRMT2各剪接体有可能和PRMT2一样通过ERα信号途径影响乳腺癌的发生发展.     

重组 GST-β-GT 融合蛋白的原核表达、纯化及活性鉴定

目的：构建噬菌体β‐GT蛋白的原核重组体系,诱导表达、纯化GST‐β‐GT 融合蛋白并对其进行酶活性测定。方法利用PCR技术从T4噬菌体中扩增β‐GT基因;经T‐A克隆,获得β‐GT基因片段,经酶切连接,构建原核表达载体pGEX‐6P‐1‐β‐GT ;经测序鉴定序列正确后,将所构建的载体转化进入大肠埃希菌BL21（DE3）中进行表达。利用IPTG诱导,经10％ SDS‐PAGE鉴定目的蛋白表达后,采用GST柱纯化目的蛋白;通过酶切和qPCR鉴定其活性。结果成功扩增了噬菌体β‐GT基因;重组质粒在大肠埃希菌BL21（DE3）中诱导表达出GST‐β‐GT融合蛋白;通过GST柱纯化后获得了GST‐β‐GT融合蛋白,纯度达95％;通过酶切和qPCR验证,此GST‐β‐GT融合蛋白具有T4‐β‐GT酶的活性。结论。原核表达GST‐β‐GT融合蛋白具有糖基转移酶活性。     

耐两性霉素B的近平滑与热带假丝酵母菌的体外诱导及耐药分子机制研究

目的：体外诱导近平滑假丝酵母菌（ CP）、热带假丝酵母菌（ CT）对两性霉素B（ AMB）的耐药株,检测其中的耐药基因表达情况。方法 AMB体外构建耐药株,用实时荧光定量PCR法检测耐药基因的表达水平。结果 CP、CT 野生株经体外 AMB 浓度递增法诱导后,形成耐药株最低抑菌浓度（ MIC,≥8μg? mL－1）;CYP51A、CYP51B、CDR1、CDR2、MDR1及MDR2基因在野生株中低水平表达,在耐药株中表达水平明显升高,差别有统计学意义（ P ＜0．05）;CYP51A、CYP51B、CDR1、CDR2、MDR1及MDR2的表达量在CPAMB耐药株中分别是其野生株的136．92,16．33,2．07,14．84,4．07,2．38倍;在CT AMB耐药株中分别是其野生株的8．83,2．98,3．00,2．40,2．30,3．57倍。结论 CP、CT对AMB耐药与CYP51A、CYP51B、CDR1、CDR2、MDR1及MDR2基因过度表达有关。     

Effect of Bacillus subtilis,Enterococcus faecium,and Enterococcus faecalis supernatants on serotonin transporter expression in cells and tissues

BACKGROUND Bacillus subtilis(B.subtilis),Enterococcus faecium(E.faecium),and Enterococcus faecalis(E.faecalis)are probiotics that are widely used in the clinical treatment of irritable bowel syndrome(IBS).Whether the supernatants of these three probiotics can improve gastrointestinal sensation and movement by regulating the serotonin transporter(SERT)expression needs to be clarified.AIM To investigate whether B.subtilis,E.faecium,and E.faecalis supernatants can upregulate SERT expression in vitro and in vivo.METHODS Caco-2 and HT-29 cells were stimulated with probiotic culture supernatants for 12 and 24 h,respectively.A male Sprague-Dawley rat model of post-infectious irritable bowel syndrome(PI-IBS)was established and the rats were treated with phosphate-buffered saline(group A)and three probiotics culture supernatants(groups B,C,and D)for 4 wk.The levels of SERT were detected by quantitative PCR and western blotting.RESULTS The levels of SERT at post-treatment 12 and 24 h were significantly elevated in Caco-2 cells treated with B.subtilis supernatant compared with those in the control group(aP<0.05).Those levels were markedly upregulated in Caco-2 cells stimulated with E.faecium and E.faecalis supernatants at 24 h(aP<0.05).In addition,SERT expression in groups B,C,and D was significantly higher than that in group A in the 2nd wk(aP<0.05).Increased SERT expression was only found in group D in the 3rd wk(aP<0.05).However,there was no significant difference in SERT expression between the groups in the last week(P>0.05).CONCLUSION The supernatants of B.subtilis,E.faecium,and E.faecalis can upregulate SERT expression in intestinal epithelial cells and the intestinal tissues in the rat model of PI-IBS.     

弓形虫GRA6可溶性蛋白在大肠埃希菌中的表达及纯化

目的在大肠埃希菌中高效表达及纯化弓形虫GRA6抗原,为制作弓形虫感染基因工程诊断试剂盒奠定基础.方法将重组pGEX-GRA6表达载体转化大肠埃希菌BL21-Codon Plus（DE3）-RP菌株,在异丙基硫代-β-D半乳糖苷（IPTG）诱导下表达.超声破壁后,通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析表达产物的表达形式,并对表达产物以硫酸铵沉淀、Sephedax G50脱盐和GST亲和层析柱进行目的蛋白的纯化.通过Western blotting检测其纯化的重组抗原的免疫反应性.结果GRA6以融合蛋白（GST-GRA6）的形式在大肠埃希菌中得到了高效表达.对表达产物可溶性分析表明,表达蛋白在上清液中和包涵体中均有表达.在上清液中表达的可溶性蛋白经纯化后蛋白纯度可达90%以上.Western blotting分析表明纯化蛋白能被弓形虫感染的人血清所识别.结论GRA6在大肠埃希菌中得到了高效表达,重组抗原经纯化后能特异性地被弓形虫感染者血清所识别.     

严重急性呼吸综合征冠状病毒刺突蛋白在酿酒酵母中的表达和纯化

目的构建重组表达质粒pYES6-S，诱导SARS冠状病毒刺突蛋白（spikeprotein）在酿酒酵母中的表达并纯化。方法反转录获得SARS冠状病毒DNA片段，PCR法获得刺突蛋白基因互相重叠的四部分片段，酶切连接成全长，在大肠埃希菌E．coliJM109中构建重组表达克隆pYES6-S，在酿酒酵母巾诱导表达并纯化。结果重组克隆pYES6～S经酶切、测序鉴定确定，插入片段大小、方向、碱基匹配与预期一致，获得1个完整的刺突蛋白基因，表达产物纯化后，电泳鉴定，相对分子质量大小近110000。结论 成功克隆SARS冠状病毒刺突蛋白基因全长，并在酿酒酵母中诱导表达成功，有助于抗SARS分子疫苗的研究。     

重组人肝再生增强因子抑制实验性肝纤维化明胶酶A基因表达

目的　了解重组人肝再生增强因子 (hALR)对实验性肝纤维化明胶酶A(MMP2 )基因表达的影响。方法　建立CCl4中毒性及人血白蛋白免疫损伤性两种大鼠肝纤维化模型 ,在造模的同时给予不同剂量 (10 ,5 0 μg·kg-1·d-1)的hALR。在不同的时间点留取大鼠肝组织标本 ,提取总RNA ,用逆转录定量聚合酶链反应 (RT PCR)测定MMP2 的基因表达水平。结果　在两种模型中两个剂量hALR预防组大鼠肝组织MMP2 的基因表达水平在模型形成的不同阶段均明显低于模型组 ;高剂量hALR组大鼠肝组织MMP2 的基因表达水平均明显低于低剂量组。结论　重组人肝再生增强因子可能有抑制大鼠实验性肝纤维化MMP2 基因表达的作用     

Towards a molecular approach to gastric cancer management

Abstract
Gastric cancer is a leading cause of cancer death worldwide. Most patients with gastric cancer present with locally advanced and incurable disease, and overall survival is poor. Considerable research efforts towards the epidemiology and pathogenesis of gastric cancer have not been translated into treatment success. We discuss current concepts of the pathogenesis of gastric cancer and how recent research advances, in particular global gene expression strategies, may improve this understanding, and suggest a framework wherein these approaches may be used. (Intern Med J 2001; 31: 296–303)