Inducing expression and the reaction characteristic of nitrile hydratase （NHase） from Rhodococcus sp. SHZ-1 were investigated. The results showed that the expression of NHase was greatly enhanced with the cooperatio...Inducing expression and the reaction characteristic of nitrile hydratase （NHase） from Rhodococcus sp. SHZ-1 were investigated. The results showed that the expression of NHase was greatly enhanced with the cooperation of acrylonitrile and ammonium chloride as inducer in the medium and the specific activity of NHase was increased of 44%. Then the temperature, pH, concentration of acrylonitrile and acrylamide were evaluated, which affected the activity and reaction characteristic of NHase. It was found that the temperature and concentration of acrylarnide were the most important factors for the catalyzation of NHase. The optimal catalysis temperature of NHase from Rhodococcus sp. SHZ-1 was 30℃, and the activation energy of the hydration of NHase was 90.2kJ·mol^-1 in the temperature range from 5℃ to 30℃. Kmof NHase was 0.095mol·L^-1 using acrylonitrile（AN） as substrate, and NHase activity was inhibited seriously when acrylonitrile concentration was up to 40g·L^-1, the substrate inhibition constant Ki is 0.283mol·L^-1. Moreover, the NHase from Rhodococcus sp. SHZ-1 had very strong tolerance to acrylamide, in which the final concentration of acrylamide reached to 642g·L^-1 and the residual activity of NHase still maintained 8.6% of the initial enzyme activity.展开更多
为了进一步研究烯脂酰辅酶A水解酶1(enoyl CoA hydratase,ECH1)基因的生物学功能,研究采用克隆测序结合PCR-RFLP的方法分析了民猪ECH1基因的部分DNA序列,并对其中的1个点突变进行了3个猪种内的基因型频率和基因频率计算。结果表明:研究...为了进一步研究烯脂酰辅酶A水解酶1(enoyl CoA hydratase,ECH1)基因的生物学功能,研究采用克隆测序结合PCR-RFLP的方法分析了民猪ECH1基因的部分DNA序列,并对其中的1个点突变进行了3个猪种内的基因型频率和基因频率计算。结果表明:研究所检测的ECH1基因序列与网上已有序列相比存在8个单核苷酸多态性(SNPs)位点,其中有2个造成酶切位点的改变;民猪和大白猪在PCR-RFLP-BamHⅠ位点的A、B基因频率均接近0.5,而长白猪B为优势等位基因。展开更多
目的:观察烯脂酰辅酶A水合酶短链1(enoyl-coenzyme A hydratase,short chain1,ECHS1)对肝癌HepG2细胞增殖的影响。方法:将干扰ECHS1基因的重组质粒pGPU6/GFP/siRNA-ECHS1转染至HepG2细胞,通过嘌呤霉素筛选稳定干扰ECHS1基因表达的HepG2...目的:观察烯脂酰辅酶A水合酶短链1(enoyl-coenzyme A hydratase,short chain1,ECHS1)对肝癌HepG2细胞增殖的影响。方法:将干扰ECHS1基因的重组质粒pGPU6/GFP/siRNA-ECHS1转染至HepG2细胞,通过嘌呤霉素筛选稳定干扰ECHS1基因表达的HepG2细胞,蛋白质印迹法检测细胞中ECHS1蛋白的表达水平。pGPU6/GFP/siRNA-ECHS1转染HepG2细胞后,CCK-8(cellcountingkit-8)和5-溴脱氧尿嘧啶核苷(5-bromo-2’-deoxyuridine,BrdU)法检测细胞的增殖情况,蛋白质印迹法检测细胞中细胞外信号调节激酶(extracellular signal regulated kinase,ERK)、磷酸化ERK(phosphorylated-ERK,p-ERK)、cyclinD3和cyclinD1蛋白的表达水平。结果:成功建立稳定干扰ECHS1基因表达的HepG2细胞,pGPU6/GFP/siRNA-ECHS1转染后HepG2细胞中ECHS1蛋白的表达水平明显低于空白对照组(未转染质粒的HepG2细胞)和阴性对照组(转染空载体pGPU6的HepG2细胞)(P<0.05)。与阴性对照组比较,pGPU6/GFP/siRNA-ECHS1转染后HepG2细胞的增殖能力受到明显抑制(P<0.05),p-ERK、cyclinD3和cyclinD1蛋白的表达水平均明显降低(P<0.05)。结论:ECHS1可能通过上调p-ERK、cyclinD3和cyclinD1的表达而促进肝癌HepG2细胞的增殖。展开更多
基金Supported by the National Natural Science Foundation of China （No.20466002）, the Program for New Century Excellent Talents in University （NCET-04-089） and the Key Research Projects in the Uygur Autonomous Region of Xinjiang （No.200332109）.
文摘Inducing expression and the reaction characteristic of nitrile hydratase （NHase） from Rhodococcus sp. SHZ-1 were investigated. The results showed that the expression of NHase was greatly enhanced with the cooperation of acrylonitrile and ammonium chloride as inducer in the medium and the specific activity of NHase was increased of 44%. Then the temperature, pH, concentration of acrylonitrile and acrylamide were evaluated, which affected the activity and reaction characteristic of NHase. It was found that the temperature and concentration of acrylarnide were the most important factors for the catalyzation of NHase. The optimal catalysis temperature of NHase from Rhodococcus sp. SHZ-1 was 30℃, and the activation energy of the hydration of NHase was 90.2kJ·mol^-1 in the temperature range from 5℃ to 30℃. Kmof NHase was 0.095mol·L^-1 using acrylonitrile（AN） as substrate, and NHase activity was inhibited seriously when acrylonitrile concentration was up to 40g·L^-1, the substrate inhibition constant Ki is 0.283mol·L^-1. Moreover, the NHase from Rhodococcus sp. SHZ-1 had very strong tolerance to acrylamide, in which the final concentration of acrylamide reached to 642g·L^-1 and the residual activity of NHase still maintained 8.6% of the initial enzyme activity.
文摘为了进一步研究烯脂酰辅酶A水解酶1(enoyl CoA hydratase,ECH1)基因的生物学功能,研究采用克隆测序结合PCR-RFLP的方法分析了民猪ECH1基因的部分DNA序列,并对其中的1个点突变进行了3个猪种内的基因型频率和基因频率计算。结果表明:研究所检测的ECH1基因序列与网上已有序列相比存在8个单核苷酸多态性(SNPs)位点,其中有2个造成酶切位点的改变;民猪和大白猪在PCR-RFLP-BamHⅠ位点的A、B基因频率均接近0.5,而长白猪B为优势等位基因。
文摘【目的】在分子层面上研究家蚕微孢子虫Nosema bombycis与家蚕Bombyx mori蛋白的相互作用,初步探讨家蚕微孢子虫向家蚕细胞能量中心靠近的原因。【方法】采用Far-western blot分析与家蚕微孢子虫具有相互作用的家蚕中肠蛋白,质谱鉴定筛选出候选蛋白。PCR扩增候选蛋白的基因,连接到p ET30a载体并转入大肠杆菌Escherichia coli DH5α感受态细胞培养,测序选取正确的3个重组质粒,转化到大肠杆菌E.coli BL21感受态细胞中诱导表达候选蛋白,亲和层析柱纯化候选蛋白,制备多克隆抗体。用免疫共沉淀和间接免疫荧光技术验证候选蛋白与家蚕微孢子虫的相互作用。【结果】Far-western blot筛选到的anti-SWP9和anti-SWP5抗体与感染家蚕微孢子虫的家蚕中肠总蛋白的PVDF膜孵育,分别在26 k D和34 k D处检测到一条特异条带,说明家蚕微孢子虫与26 k D和34 k D的家蚕中肠蛋白发生了相互作用。对质谱鉴定结果进行蛋白质的分子量、肽段数以及功能的分析,筛选出与家蚕微孢子虫相互作用的候选家蚕蛋白烯酰辅酶A水合酶(ECH1)、甘油醛-3-磷酸脱氢酶(GAPDH)和3-羟酰辅酶A脱氢酶(HCDH)。利用制备的能够特异识别ECH1,GAPDH和HCDH 3种蛋白的多克隆抗体anti-ECH1,anti-GAPDH和anti-HCDH进行免疫共沉淀,证实了家蚕微孢子虫与家蚕中肠蛋白ECH1和GAPDH具有相互作用;间接免疫荧光分析结果进一步说明GAPDH能与家蚕微孢子虫特异性结合。【结论】家蚕微孢子虫可以和家蚕蛋白ECH1和GAPDH特异性结合。由于ECH1是定位于线粒体膜上的脂肪酸β-氧化的关键酶,GAPDH是糖酵解途径的关键酶,推测家蚕微孢子虫可能通过和家蚕ECH1和GAPDH的相互作用,在空间上靠近宿主细胞的线粒体和糖酵解途径,便于摄取宿主细胞脂肪酸β-氧化和糖酵解途径产生的中间产物和ATP,满足家蚕微孢子虫的物质和能量需求。
文摘目的:观察烯脂酰辅酶A水合酶短链1(enoyl-coenzyme A hydratase,short chain1,ECHS1)对肝癌HepG2细胞增殖的影响。方法:将干扰ECHS1基因的重组质粒pGPU6/GFP/siRNA-ECHS1转染至HepG2细胞,通过嘌呤霉素筛选稳定干扰ECHS1基因表达的HepG2细胞,蛋白质印迹法检测细胞中ECHS1蛋白的表达水平。pGPU6/GFP/siRNA-ECHS1转染HepG2细胞后,CCK-8(cellcountingkit-8)和5-溴脱氧尿嘧啶核苷(5-bromo-2’-deoxyuridine,BrdU)法检测细胞的增殖情况,蛋白质印迹法检测细胞中细胞外信号调节激酶(extracellular signal regulated kinase,ERK)、磷酸化ERK(phosphorylated-ERK,p-ERK)、cyclinD3和cyclinD1蛋白的表达水平。结果:成功建立稳定干扰ECHS1基因表达的HepG2细胞,pGPU6/GFP/siRNA-ECHS1转染后HepG2细胞中ECHS1蛋白的表达水平明显低于空白对照组(未转染质粒的HepG2细胞)和阴性对照组(转染空载体pGPU6的HepG2细胞)(P<0.05)。与阴性对照组比较,pGPU6/GFP/siRNA-ECHS1转染后HepG2细胞的增殖能力受到明显抑制(P<0.05),p-ERK、cyclinD3和cyclinD1蛋白的表达水平均明显降低(P<0.05)。结论:ECHS1可能通过上调p-ERK、cyclinD3和cyclinD1的表达而促进肝癌HepG2细胞的增殖。
