为探索大肠杆菌Nissle 1917株(EcN)鞭毛展示的应用,本研究以重组质粒p UC18-fli C为模板,反向PCR产物经DpnⅠ、Exnase^(TM)Ⅱ重组环化,将6His标签基因分别插入无质粒大肠杆菌Nissle 1917(EcNcured of its two cryptic plasmids p MUT1和...为探索大肠杆菌Nissle 1917株(EcN)鞭毛展示的应用,本研究以重组质粒p UC18-fli C为模板,反向PCR产物经DpnⅠ、Exnase^(TM)Ⅱ重组环化,将6His标签基因分别插入无质粒大肠杆菌Nissle 1917(EcNcured of its two cryptic plasmids p MUT1和p MUT2;EcNc)fli C高变区774 bp^775 bp和792 bp^811 bp之间,构建嵌合鞭毛基因片段fliC01和fliC02。分别将其克隆于自杀性载体pRE112中,构建重组质粒pRE112-fliC01和pRE112-fliC02,并分别转化至EcNc中。通过一次重组和二次重组将嵌合鞭毛基因整合于EcNc基因组中,构建无抗性筛选的重组菌株EcNc fliC01和EcNc fliC02。对重组菌株进行生长状况、鞭毛形成以及体外细胞黏附试验和小鼠体内定植试验检测,结果表明EcNc fliC01和EcNc fliC02的生长未受影响,表达的嵌合鞭毛能够被H1多抗或His-Tag单克隆抗体识别并组装形成鞭毛丝;重组菌对IPEC-J2细胞的黏附能力及小鼠肠道定植能力与亲本株EcNc相比无显著性差异。本实验结果为进一步研究EcNc鞭毛展示技术应用于活疫苗研制奠定了基础。展开更多
BACKGROUND Hepatic encephalopathy(HE)can be considered a result of dysregulated gutliver-brain axis function,where cognitive impairment can be reversed or prevented by the beneficial effects induced by"gut-centri...BACKGROUND Hepatic encephalopathy(HE)can be considered a result of dysregulated gutliver-brain axis function,where cognitive impairment can be reversed or prevented by the beneficial effects induced by"gut-centric"therapies,such as the administration of nonabsorbable disaccharides,nonabsorbable antibiotics,probiotics and prebiotics.AIM To assess the short-term efficacy and safety of the probiotic Escherichia coli Nissle(EcN)1917 strain compared to lactulose and rifaximin in patients with minimal/mild HE.METHODS From January 2017 to March 2020,a total of 45 patients with HE were enrolled in this prospective,single-centre,open-label,randomized study.Participants were randomly assigned at a ratio of 1:1:1 to one of the treatment groups:The EcN group(n=15),lactulose group(n=15)or rifaximin group(n=15)for a 1 mo intervention period.The main primary outcomes of the study were changes in serum ammonia and Stroop test score.The secondary outcomes were markers of a chronic systemic inflammatory response(ІL-6,ІL-8,and IFN-γ)and bacteriology of the stool flora evaluated by specialized nonculture techniques after a 1 mo intervention period.RESULTS Patients who were given rifaximin or EcN showed a more significant reduction in serum ammonia and normalization of Bifidobacteria and Lactobacilli abundance compared to the lactulose group.However,the most pronounced restoration of the symbiotic microflora was associated with EcN administration and characterized by the absence of E.coli with altered properties and pathogenic enterobacteria in patient faeces.In the primary outcome analysis,improvements in the Stroop test parameters in all intervention groups were observed.Moreover,EcN-treated patients performed 15%faster on the Stroop test than the lactulose group patients(P=0.017).Both EcN and rifaximin produced similar significant reductions in the proinflammatory cytokines INF-γ,IL-6 and IL-8.EcN was more efficient than lactulose in reducing proinflammatory cytokine levels.CONCLUSION The use of the probiotic EcN strain was safe and quite efficient for HE treatment.The probiotic reduced the ammonia content and the level of serum proinflammatory cytokines,normalized the gut microbiota composition and improved the cognitive function of patients with HE.The application of the EcN strain was more effective than lactulose treatment.展开更多
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
文摘BACKGROUND Hepatic encephalopathy(HE)can be considered a result of dysregulated gutliver-brain axis function,where cognitive impairment can be reversed or prevented by the beneficial effects induced by"gut-centric"therapies,such as the administration of nonabsorbable disaccharides,nonabsorbable antibiotics,probiotics and prebiotics.AIM To assess the short-term efficacy and safety of the probiotic Escherichia coli Nissle(EcN)1917 strain compared to lactulose and rifaximin in patients with minimal/mild HE.METHODS From January 2017 to March 2020,a total of 45 patients with HE were enrolled in this prospective,single-centre,open-label,randomized study.Participants were randomly assigned at a ratio of 1:1:1 to one of the treatment groups:The EcN group(n=15),lactulose group(n=15)or rifaximin group(n=15)for a 1 mo intervention period.The main primary outcomes of the study were changes in serum ammonia and Stroop test score.The secondary outcomes were markers of a chronic systemic inflammatory response(ІL-6,ІL-8,and IFN-γ)and bacteriology of the stool flora evaluated by specialized nonculture techniques after a 1 mo intervention period.RESULTS Patients who were given rifaximin or EcN showed a more significant reduction in serum ammonia and normalization of Bifidobacteria and Lactobacilli abundance compared to the lactulose group.However,the most pronounced restoration of the symbiotic microflora was associated with EcN administration and characterized by the absence of E.coli with altered properties and pathogenic enterobacteria in patient faeces.In the primary outcome analysis,improvements in the Stroop test parameters in all intervention groups were observed.Moreover,EcN-treated patients performed 15%faster on the Stroop test than the lactulose group patients(P=0.017).Both EcN and rifaximin produced similar significant reductions in the proinflammatory cytokines INF-γ,IL-6 and IL-8.EcN was more efficient than lactulose in reducing proinflammatory cytokine levels.CONCLUSION The use of the probiotic EcN strain was safe and quite efficient for HE treatment.The probiotic reduced the ammonia content and the level of serum proinflammatory cytokines,normalized the gut microbiota composition and improved the cognitive function of patients with HE.The application of the EcN strain was more effective than lactulose treatment.
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.
