CS3 fimbriae, which are the strong immunogen, are produced by human enterotoxigenic Escherichia coli (ETEC). The possibility of using CS3 as a carrier of foreign antigenic determinants was investigated. A SacⅡ site s...CS3 fimbriae, which are the strong immunogen, are produced by human enterotoxigenic Escherichia coli (ETEC). The possibility of using CS3 as a carrier of foreign antigenic determinants was investigated. A SacⅡ site sequence was inserted into the structural gene of CS3 subunit by site-specific mutagenesis based on analyzing and predicting the properties of the proteins. A recombinant strain expressing CS3/CTP3 hybrid fimbriae was constructed by inserting the sequence encoding CTP3 into the SacII site created by directed mutagenesis in the structural gene of CS3 subunit and transforming the recombinant plasmid into the host of DH5α. The result of SDS-PAGE showed that the hybrid CS3/CTP3 molecules were the fusion proteins with molecular masses of about 18.5 ku. Inoculating mice orally and intraperitoneally showed that both antibodies against CS3 and CTP3 were elicited. These results indicate that CS3 pili could be an exposure vector for heterologous antigenic determinants and become a powerful tool for the development of oral vaccines directed against mucosal pathogens.展开更多
Uropathogenic Escherichia coli(UPEC)is the leading cause of urinary tract infections in women,causing significant morbidity and mortality in this population.Adherence to host epithelial cells is a pivotal step in the ...Uropathogenic Escherichia coli(UPEC)is the leading cause of urinary tract infections in women,causing significant morbidity and mortality in this population.Adherence to host epithelial cells is a pivotal step in the pathogenesis of UPEC.One of the most important virulence factors involved in mediating this attachment is the type 1 pilus(type 1 fimbria)encoded by a set of fim genes arranged in an operon.The expression of type 1 pili is controlled by a phenomenon known as phase variation,which reversibly switches between the expression of type 1 pili(Phase-ON)and loss of expression(Phase-OFF).Phase-ON cells have the promoter for the fimA structural gene on an invertible DNA element called fimS,which lines up to allow transcription,whereas transcription of the structural gene is silenced in Phase-OFF cells.The orientation of the fimS invertible element is controlled by two site-specific recombinases,FimB and FimE.Environmental conditions cause transcriptional and post-transcriptional changes in UPEC cells that affect the level of regulatory proteins,which in turn play vital roles in modulating this phase switching ability.The role of fim gene regulation in UPEC pathogenesis will be discussed.展开更多
[Objective] This paper aimed to study the mechanism of diarrhea of mink caused by Escherichia coil [Method] Through the detection of K88 fimbriae gene of E. coli, cloning of gene fragments and identification, then PCR...[Objective] This paper aimed to study the mechanism of diarrhea of mink caused by Escherichia coil [Method] Through the detection of K88 fimbriae gene of E. coli, cloning of gene fragments and identification, then PCR amplification was used to detect adhesion factor K88 gene, which was connected to T-vector and transformed into competent cells, and positive clones were selected. [ Results] E. coli 078, 029 and 038 were isolated from organs and feces of mink died of diarrhea in 3 mink farms, respectively, the 3 serotypes of E. coliwere detected in carrying K88 fimbriae gene and 3 positive clones were screened, respectively. [ Conclusion] The E. coli causing mink diarrhea carry K88 fimbriae gene.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 39570408)
文摘CS3 fimbriae, which are the strong immunogen, are produced by human enterotoxigenic Escherichia coli (ETEC). The possibility of using CS3 as a carrier of foreign antigenic determinants was investigated. A SacⅡ site sequence was inserted into the structural gene of CS3 subunit by site-specific mutagenesis based on analyzing and predicting the properties of the proteins. A recombinant strain expressing CS3/CTP3 hybrid fimbriae was constructed by inserting the sequence encoding CTP3 into the SacII site created by directed mutagenesis in the structural gene of CS3 subunit and transforming the recombinant plasmid into the host of DH5α. The result of SDS-PAGE showed that the hybrid CS3/CTP3 molecules were the fusion proteins with molecular masses of about 18.5 ku. Inoculating mice orally and intraperitoneally showed that both antibodies against CS3 and CTP3 were elicited. These results indicate that CS3 pili could be an exposure vector for heterologous antigenic determinants and become a powerful tool for the development of oral vaccines directed against mucosal pathogens.
文摘Uropathogenic Escherichia coli(UPEC)is the leading cause of urinary tract infections in women,causing significant morbidity and mortality in this population.Adherence to host epithelial cells is a pivotal step in the pathogenesis of UPEC.One of the most important virulence factors involved in mediating this attachment is the type 1 pilus(type 1 fimbria)encoded by a set of fim genes arranged in an operon.The expression of type 1 pili is controlled by a phenomenon known as phase variation,which reversibly switches between the expression of type 1 pili(Phase-ON)and loss of expression(Phase-OFF).Phase-ON cells have the promoter for the fimA structural gene on an invertible DNA element called fimS,which lines up to allow transcription,whereas transcription of the structural gene is silenced in Phase-OFF cells.The orientation of the fimS invertible element is controlled by two site-specific recombinases,FimB and FimE.Environmental conditions cause transcriptional and post-transcriptional changes in UPEC cells that affect the level of regulatory proteins,which in turn play vital roles in modulating this phase switching ability.The role of fim gene regulation in UPEC pathogenesis will be discussed.
基金China Postdoctoral Sustentation Fund(NO.20100470565)Hebei Sustain Program of Science and Technology(NO.10960408D)Qinhuangdao Scientific and Technological Development Program(NO.201101A182)
文摘[Objective] This paper aimed to study the mechanism of diarrhea of mink caused by Escherichia coil [Method] Through the detection of K88 fimbriae gene of E. coli, cloning of gene fragments and identification, then PCR amplification was used to detect adhesion factor K88 gene, which was connected to T-vector and transformed into competent cells, and positive clones were selected. [ Results] E. coli 078, 029 and 038 were isolated from organs and feces of mink died of diarrhea in 3 mink farms, respectively, the 3 serotypes of E. coliwere detected in carrying K88 fimbriae gene and 3 positive clones were screened, respectively. [ Conclusion] The E. coli causing mink diarrhea carry K88 fimbriae gene.
