Proteins in aquatic products satisfy the increasing demand of high-quality proteins of humans, resulting in a rapid development of freshwater aquaculture. However, bacterial diseases in aquatic animals often cause eco...Proteins in aquatic products satisfy the increasing demand of high-quality proteins of humans, resulting in a rapid development of freshwater aquaculture. However, bacterial diseases in aquatic animals often cause economic losses worldwide. Antibiotics are frequently used in aquaculture to deal with bacterial infections, but antibiotic resistance has restricted its application. Therefore, it is necessary to develop drugs on account of novel strategies. Here, aerolysin, the main virulence factor of Aeromonas hydrophila (A. hydrophila), was defined as a target to develop anti-virulence drugs. The results showed that Licochalcone A (LCA) with little bacteriostatic activity could decrease the hemolytic activity of aerolysin without affecting its production. The binding mode and potential binding sites were determined following molecular docking and dynamic simulation. Ser33 and Pro365 were confirmed to be the main binding sites according to the results of fluorescence quenching assay with mutated aerolysin. The mechanism by which LCA inhibited aerolysin was hindering its pore-forming activity. Moreover, cell viability assays and animal studies demonstrated that LCA could provide a significant protection to human alveolar epithelial cells from aerolysin-mediated cell damage and decrease the pathogenicity of A. hydrophila to channel catfish. These findings suggested that LCA might be a novel candidate for treating A. hydrophila infections and partly determined the mechanism of herbal medicine in dealing with bacterial infections.展开更多
Membrane protein molecules can self-assemble to form a single-biomolecule interface,which can accommodate one single molecule at a time and provide a suitable sensing environment for single-molecule measurements.To ac...Membrane protein molecules can self-assemble to form a single-biomolecule interface,which can accommodate one single molecule at a time and provide a suitable sensing environment for single-molecule measurements.To achieve the high temporal and spatial resolution for revealing the heterogenous of single molecules,one of the most important challenge is to construct a functional single-biomolecule interface.展开更多
Vaccines are one of the most practical means to stop the spreading of Aeromonas veronii in aquaculture.In this study,virulence factor aerolysin mutant NTaer which has lost its hemolytic activity was used as a target a...Vaccines are one of the most practical means to stop the spreading of Aeromonas veronii in aquaculture.In this study,virulence factor aerolysin mutant NTaer which has lost its hemolytic activity was used as a target antigen.Pichia pastoris constitutive secretory expression NTaer(GS115-NTaer)was used as a potential safe oral vaccine to evaluate its effectiveness on zebrafish immunity.The result shows that vaccination of GS115-NTaer for four weeks did not affect the growth performance of the host,while eliciting an effective immune protective response.Compared with the control group,the GS115-NTaer could significantly up-regulate the relative expression level of the intestinal tight junction protein 1α(TJP1α)gene,and significantly increased the contents of lysozyme(LYZ),complement C3 and C4 in the gut,indicating that the innate immune response of the fish was activated.The relative gene expression levels of macrophage-expressed gene 1(MPEG1)and T cell receptor(TCR-α)in the gut,and MPEG1,CD4,CD8,TCR-α,GATA3,and T-bet in the spleen were all increased significantly,indicating that the cellular immune response of the fish was activated.Furthermore,the contents of serum IgM and intestinal mucosa IgZ antibodies were significantly increased,which showed that humoral immunity was also activated.Moreover,inoculation with GS115-NTaer significantly changed the structure of gut microbiota.In particular,the relative ratio of(Firmicutes+Fusobacteriota+Bacteroidota)/Proteobacteria was significantly higher than that of the control and GS115 groups.Lastly,the vaccinated fish were challenged with A.veronii,and the relative percent survival of GS115 and the GS115-NTear groups was 14.28%and 33.43%.This improvement of immunity was not only due to the specific immune response but also attributed to the improvement of innate immunity and the gut microbiota which was demonstrated by the germ-free zebrafish model.Collectively,this study provides information on the effectiveness of GS115-NTear as an oral vaccine for the green prevention and control of A.veronii infection in fish aquaculture.展开更多
基金supported by the National Natural Science Foundation of China(No.32473208)China Agriculture Research System(CARS-46).
文摘Proteins in aquatic products satisfy the increasing demand of high-quality proteins of humans, resulting in a rapid development of freshwater aquaculture. However, bacterial diseases in aquatic animals often cause economic losses worldwide. Antibiotics are frequently used in aquaculture to deal with bacterial infections, but antibiotic resistance has restricted its application. Therefore, it is necessary to develop drugs on account of novel strategies. Here, aerolysin, the main virulence factor of Aeromonas hydrophila (A. hydrophila), was defined as a target to develop anti-virulence drugs. The results showed that Licochalcone A (LCA) with little bacteriostatic activity could decrease the hemolytic activity of aerolysin without affecting its production. The binding mode and potential binding sites were determined following molecular docking and dynamic simulation. Ser33 and Pro365 were confirmed to be the main binding sites according to the results of fluorescence quenching assay with mutated aerolysin. The mechanism by which LCA inhibited aerolysin was hindering its pore-forming activity. Moreover, cell viability assays and animal studies demonstrated that LCA could provide a significant protection to human alveolar epithelial cells from aerolysin-mediated cell damage and decrease the pathogenicity of A. hydrophila to channel catfish. These findings suggested that LCA might be a novel candidate for treating A. hydrophila infections and partly determined the mechanism of herbal medicine in dealing with bacterial infections.
基金supported by the National Natural Science Foundation of China(21834001 and 61871183)Innovation Program of Shanghai Municipal Education Commission(2017-01-07-00-02-E00023).
文摘Membrane protein molecules can self-assemble to form a single-biomolecule interface,which can accommodate one single molecule at a time and provide a suitable sensing environment for single-molecule measurements.To achieve the high temporal and spatial resolution for revealing the heterogenous of single molecules,one of the most important challenge is to construct a functional single-biomolecule interface.
基金funded by National Natural Sci-ence Foundation of China(NSFC 32303027)Agricultural Science and Technology Innovation Program(ASTIP)and Basal Research Fund(1610382023017)of the Chinese Academy of Agricultural Sciences+1 种基金Project Team of Foshan National Hi-tech Industrial Development Zone Industrialization Entrepreneurial Teams Program(2320197000012)Beijing Innovation Consortium of Agriculture Research System(BAIC07-2023-11).
文摘Vaccines are one of the most practical means to stop the spreading of Aeromonas veronii in aquaculture.In this study,virulence factor aerolysin mutant NTaer which has lost its hemolytic activity was used as a target antigen.Pichia pastoris constitutive secretory expression NTaer(GS115-NTaer)was used as a potential safe oral vaccine to evaluate its effectiveness on zebrafish immunity.The result shows that vaccination of GS115-NTaer for four weeks did not affect the growth performance of the host,while eliciting an effective immune protective response.Compared with the control group,the GS115-NTaer could significantly up-regulate the relative expression level of the intestinal tight junction protein 1α(TJP1α)gene,and significantly increased the contents of lysozyme(LYZ),complement C3 and C4 in the gut,indicating that the innate immune response of the fish was activated.The relative gene expression levels of macrophage-expressed gene 1(MPEG1)and T cell receptor(TCR-α)in the gut,and MPEG1,CD4,CD8,TCR-α,GATA3,and T-bet in the spleen were all increased significantly,indicating that the cellular immune response of the fish was activated.Furthermore,the contents of serum IgM and intestinal mucosa IgZ antibodies were significantly increased,which showed that humoral immunity was also activated.Moreover,inoculation with GS115-NTaer significantly changed the structure of gut microbiota.In particular,the relative ratio of(Firmicutes+Fusobacteriota+Bacteroidota)/Proteobacteria was significantly higher than that of the control and GS115 groups.Lastly,the vaccinated fish were challenged with A.veronii,and the relative percent survival of GS115 and the GS115-NTear groups was 14.28%and 33.43%.This improvement of immunity was not only due to the specific immune response but also attributed to the improvement of innate immunity and the gut microbiota which was demonstrated by the germ-free zebrafish model.Collectively,this study provides information on the effectiveness of GS115-NTear as an oral vaccine for the green prevention and control of A.veronii infection in fish aquaculture.
