Microbial infections are typically initiated by the colonization of tissues by a specific mechanism that promotes adherence to host cells or tissues. In this work, we characterized the ability of Gallibacterium anatis...Microbial infections are typically initiated by the colonization of tissues by a specific mechanism that promotes adherence to host cells or tissues. In this work, we characterized the ability of Gallibacterium anatis F149T to express fimbriae that may be involved in mucosal attachment. Using transmission electron microscopy, the fimbriae-like structures could be observed on the surface of negatively stained G. anatis F149T, and these structures were further visualized after being released by physical shaking. When the fimbriae-like structures were separated by SDS-PAGE, the proteins comprising them were isolated and sized at 13 and 25 kDa. G. anatis F149T was able to adhere to chicken oropharyngeal epithelial cells. Adhesion could be completely inhibited by pretreatment of the bacterial cells with trypsin, whereas 25% inhibition was attained after pretreatment with an antiserum against the 13 kDa protein. We demonstrated by immuno-gold electron microscopy that the antibodies from the antiserum were specifically associated with the fimbria-like structures on G. anatis. These results indicated that G. anatis F149T expresses fimbriae that contribute to its adhesion to chicken oropharyngeal epithelial cells and may be important for colonization of the upper respiratory tract.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
Photodynamic therapy(PDT)holds great promise for treating periodontitis,yet its clinical efficacy is limited by the lack of specificity of conventional photosensitizers toward pathogenic bacteria.Herein,we developed a...Photodynamic therapy(PDT)holds great promise for treating periodontitis,yet its clinical efficacy is limited by the lack of specificity of conventional photosensitizers toward pathogenic bacteria.Herein,we developed a targeted photosensitizer system using a host–vip supramolecular strategy to address this challenge.The design features a selenoviologen cyclophane(SeVB)host molecule that encapsulates a Porphyromonas gingivalis(P.gingivalis)-specific binding peptide(PQGPPQF,abbreviated PQ),forming the supramolecular complex SeVB⊃PQ.Leveraging the high affinity of PQ for P.gingivalis fimbriae,SeVB⊃PQ demonstrates exceptional bacterial targeting capability,achieving a colocalization coefficient of 0.669.Upon light activation,SeVB⊃PQ generates elevated intracellular reactive oxygen species while disrupting adenosine triphosphate synthesis in P.gingivalis,resulting in a 33.12%enhancement in antimicrobial activity compared to SeVB alone at 0.1μM.Beyond its direct bactericidal effects,SeVB⊃PQ-mediated PDT effectively restores subgingival microbiome homeostasis and attenuates microbial pathogenicity through metabolic modulation.In comparative studies with both SeVB and clinical-grade methylene blue(MB),SeVB⊃PQ demonstrated superior performance in mitigating inflammatory tissue damage and promoting periodontal regeneration.This targeted supramolecular platform not only advances PDT for periodontitis treatment but also provides a novel paradigm for the rational design of pathogen-selective photosensitizers.展开更多
Escherichia coli contains 12 chaperone-usher operons,including 64 genes,used for biosynthesis and assembly of various fimbriae which consume a lot of energy and material.In this study,each of the 12 operons was delete...Escherichia coli contains 12 chaperone-usher operons,including 64 genes,used for biosynthesis and assembly of various fimbriae which consume a lot of energy and material.In this study,each of the 12 operons was deleted in an L-threonine-producing E.coli strain TWF001,and the resulting 12 deletion mutants produced more L-threonine than TWF001 after 16 or 24 h cultivation.Therefore,the 12 chaperone-usher operons were deleted in different combinations,resulting in 11 strain mutants which lack at least 2 operons.The cell growth and L-threonine production of these 11 mutants were determined.Among these 11 mutants,TWK021 in which 10 chaperone-usher operons were deleted,showed the highest L-threonine production.TWK021 produced 15.75 g L-threonine from 40 g glucose after 36 h cultivation.The conversion rate of glucose to L-threonine reached 0.394 g/g in TWK021,which is 32.2%higher than the control strain TWF001.These results suggest that the fimbria lacking E.coli TWK021 is a good host for efficient production of L-threonine.展开更多
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
文摘Microbial infections are typically initiated by the colonization of tissues by a specific mechanism that promotes adherence to host cells or tissues. In this work, we characterized the ability of Gallibacterium anatis F149T to express fimbriae that may be involved in mucosal attachment. Using transmission electron microscopy, the fimbriae-like structures could be observed on the surface of negatively stained G. anatis F149T, and these structures were further visualized after being released by physical shaking. When the fimbriae-like structures were separated by SDS-PAGE, the proteins comprising them were isolated and sized at 13 and 25 kDa. G. anatis F149T was able to adhere to chicken oropharyngeal epithelial cells. Adhesion could be completely inhibited by pretreatment of the bacterial cells with trypsin, whereas 25% inhibition was attained after pretreatment with an antiserum against the 13 kDa protein. We demonstrated by immuno-gold electron microscopy that the antibodies from the antiserum were specifically associated with the fimbria-like structures on G. anatis. These results indicated that G. anatis F149T expresses fimbriae that contribute to its adhesion to chicken oropharyngeal epithelial cells and may be important for colonization of the upper respiratory tract.
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.
基金supported by the National Natural Science Foundation of China(22175138,22201228,22205172,52203240,82170927)the Guangdong Basic and Applied Basic Research Foundation(2023A1515110346)We thank the Interdisciplinary Training Program for Doctoral Candidates of Xi’an Jiaotong University(IDT2026).
文摘Photodynamic therapy(PDT)holds great promise for treating periodontitis,yet its clinical efficacy is limited by the lack of specificity of conventional photosensitizers toward pathogenic bacteria.Herein,we developed a targeted photosensitizer system using a host–vip supramolecular strategy to address this challenge.The design features a selenoviologen cyclophane(SeVB)host molecule that encapsulates a Porphyromonas gingivalis(P.gingivalis)-specific binding peptide(PQGPPQF,abbreviated PQ),forming the supramolecular complex SeVB⊃PQ.Leveraging the high affinity of PQ for P.gingivalis fimbriae,SeVB⊃PQ demonstrates exceptional bacterial targeting capability,achieving a colocalization coefficient of 0.669.Upon light activation,SeVB⊃PQ generates elevated intracellular reactive oxygen species while disrupting adenosine triphosphate synthesis in P.gingivalis,resulting in a 33.12%enhancement in antimicrobial activity compared to SeVB alone at 0.1μM.Beyond its direct bactericidal effects,SeVB⊃PQ-mediated PDT effectively restores subgingival microbiome homeostasis and attenuates microbial pathogenicity through metabolic modulation.In comparative studies with both SeVB and clinical-grade methylene blue(MB),SeVB⊃PQ demonstrated superior performance in mitigating inflammatory tissue damage and promoting periodontal regeneration.This targeted supramolecular platform not only advances PDT for periodontitis treatment but also provides a novel paradigm for the rational design of pathogen-selective photosensitizers.
基金supported by the National Key Research and Development Program of China(2021YFC2100900).
文摘Escherichia coli contains 12 chaperone-usher operons,including 64 genes,used for biosynthesis and assembly of various fimbriae which consume a lot of energy and material.In this study,each of the 12 operons was deleted in an L-threonine-producing E.coli strain TWF001,and the resulting 12 deletion mutants produced more L-threonine than TWF001 after 16 or 24 h cultivation.Therefore,the 12 chaperone-usher operons were deleted in different combinations,resulting in 11 strain mutants which lack at least 2 operons.The cell growth and L-threonine production of these 11 mutants were determined.Among these 11 mutants,TWK021 in which 10 chaperone-usher operons were deleted,showed the highest L-threonine production.TWK021 produced 15.75 g L-threonine from 40 g glucose after 36 h cultivation.The conversion rate of glucose to L-threonine reached 0.394 g/g in TWK021,which is 32.2%higher than the control strain TWF001.These results suggest that the fimbria lacking E.coli TWK021 is a good host for efficient production of L-threonine.
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.
