The probiotic bacterium Escherichia coli Nissle 1917(EcN)holds significant promise for use in clinical and biological industries.However,the reliance on antibiotics to maintain plasmid-borne genes has overshadowed its...The probiotic bacterium Escherichia coli Nissle 1917(EcN)holds significant promise for use in clinical and biological industries.However,the reliance on antibiotics to maintain plasmid-borne genes has overshadowed its benefits.In this study,we addressed this issue by engineering the endogenous cryptic plasmids pMUT1 and pMUT2.The non-essential elements were removed to create more stable derivatives pMUT1NR△and pMUT2HBC△.Synthetic promoters by integrating binding motifs on sigma factors were further constructed and applied for expression of Bacteroides thetaiotaomicron heparinaseⅢand the biosynthesis of ectoine.Compared to traditional antibiotic-dependent expression systems,our newly constructed antibiotic-free expression systems offer considerable advantages for clinical and synthetic biology applications.展开更多
目的分析沙眼衣原体隐匿质粒编码蛋白的相互作用。方法采用基因克隆的方法将沙眼衣原体质粒基因pgp1~4及pgp8分别克隆到pRAC和pRBR上,通过转录激活细菌双杂交系统分析蛋白相互作用。结果 Western blot结果显示Pgp1、Pgp3与大肠杆菌Rpo ...目的分析沙眼衣原体隐匿质粒编码蛋白的相互作用。方法采用基因克隆的方法将沙眼衣原体质粒基因pgp1~4及pgp8分别克隆到pRAC和pRBR上,通过转录激活细菌双杂交系统分析蛋白相互作用。结果 Western blot结果显示Pgp1、Pgp3与大肠杆菌Rpo A氨基末端功能区（α-NTD）融合蛋白及Pgp1、Pgp3、Pgp4与DNA结合蛋白λCI融合蛋白,能在大肠杆菌中表达。在报告菌株中,共表达与α-NTD融合的Pgp3蛋白（α-Pgp3）及与λCI融合的Pgp3蛋白（CI-Pgp3）,导致报告基因产物β-半乳糖苷酶的活性升高。而余无明显变化。结论 pgp3编码的Pgp3能与自身相互作用。展开更多
质粒消除旨在获得无质粒菌株,是对益生菌进行遗传改造所需的一项重要技术。本试验建立在质粒不相容性的基础上,引入自杀性载体pRE112作为辅助工具,使用分子生物学方法构建重组自杀质粒pMUT1-pRE112和pMUT2-pRE112,将其分别导入携带2个...质粒消除旨在获得无质粒菌株,是对益生菌进行遗传改造所需的一项重要技术。本试验建立在质粒不相容性的基础上,引入自杀性载体pRE112作为辅助工具,使用分子生物学方法构建重组自杀质粒pMUT1-pRE112和pMUT2-pRE112,将其分别导入携带2个大隐秘质粒pMUT1和pMUT2的益生菌大肠杆菌Nissle 1917(Escherichia coli Nissle 1917,EcN),利用重组自杀质粒去除EcN内原有隐秘质粒并在含有10%蔗糖的LB培养基上实施自杀质粒自身消除。结果试验成功获得EcN无质粒克隆菌株(Escherichia coli Nissle 1917cured of its two cryptic plasmids pMUT1and pMUT2,EcNc),为优质益生菌EcN更好的潜在应用研究奠定基础。展开更多
基金financially supported by the National Natural Science Foundation of China(32370066,32000058)the Fundamental Research Funds for the Central Universities(JUSRP622003)+1 种基金National First-class Discipline Program of Light Industry Technology and Engineering(QGJC20230202)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_2487).
文摘The probiotic bacterium Escherichia coli Nissle 1917(EcN)holds significant promise for use in clinical and biological industries.However,the reliance on antibiotics to maintain plasmid-borne genes has overshadowed its benefits.In this study,we addressed this issue by engineering the endogenous cryptic plasmids pMUT1 and pMUT2.The non-essential elements were removed to create more stable derivatives pMUT1NR△and pMUT2HBC△.Synthetic promoters by integrating binding motifs on sigma factors were further constructed and applied for expression of Bacteroides thetaiotaomicron heparinaseⅢand the biosynthesis of ectoine.Compared to traditional antibiotic-dependent expression systems,our newly constructed antibiotic-free expression systems offer considerable advantages for clinical and synthetic biology applications.
文摘目的分析沙眼衣原体隐匿质粒编码蛋白的相互作用。方法采用基因克隆的方法将沙眼衣原体质粒基因pgp1~4及pgp8分别克隆到pRAC和pRBR上,通过转录激活细菌双杂交系统分析蛋白相互作用。结果 Western blot结果显示Pgp1、Pgp3与大肠杆菌Rpo A氨基末端功能区（α-NTD）融合蛋白及Pgp1、Pgp3、Pgp4与DNA结合蛋白λCI融合蛋白,能在大肠杆菌中表达。在报告菌株中,共表达与α-NTD融合的Pgp3蛋白（α-Pgp3）及与λCI融合的Pgp3蛋白（CI-Pgp3）,导致报告基因产物β-半乳糖苷酶的活性升高。而余无明显变化。结论 pgp3编码的Pgp3能与自身相互作用。
文摘质粒消除旨在获得无质粒菌株,是对益生菌进行遗传改造所需的一项重要技术。本试验建立在质粒不相容性的基础上,引入自杀性载体pRE112作为辅助工具,使用分子生物学方法构建重组自杀质粒pMUT1-pRE112和pMUT2-pRE112,将其分别导入携带2个大隐秘质粒pMUT1和pMUT2的益生菌大肠杆菌Nissle 1917(Escherichia coli Nissle 1917,EcN),利用重组自杀质粒去除EcN内原有隐秘质粒并在含有10%蔗糖的LB培养基上实施自杀质粒自身消除。结果试验成功获得EcN无质粒克隆菌株(Escherichia coli Nissle 1917cured of its two cryptic plasmids pMUT1and pMUT2,EcNc),为优质益生菌EcN更好的潜在应用研究奠定基础。
