Photocatalytic disinfection has long been used to combat pathogenic bacteria.However,the specific mechanism underlying photocatalytic disinfection and its corresponding targets remain unclear.In this study,an analysis...Photocatalytic disinfection has long been used to combat pathogenic bacteria.However,the specific mechanism underlying photocatalytic disinfection and its corresponding targets remain unclear.In this study,an analysis of the potential mechanism underlying photocatalytic disinfection was performed based on integrated metabolic networks and transcriptional data.Two sets of RNA-seq data(wild type and a photocatalysis-resistant mutant mediated by titanium dioxide(TiO2))were processed to constrain the genome scale metabolic models(GSMM)of E.coli.By analyzing the metabolic network,the differential metabolic flux of every reaction was computed in constrained GSMM,and several significantly differential metabolic fluxes in reactions were extracted and analyzed.Most of these reactions were involved in the transmembrane transport of substances and occurred on the inner membrane or were an important component of the cell membrane.These results,which are consistent with the reported information,validated our analysis process.In addition,our work also identified other new and valuable metabolic pathways,such as the reaction ALCD2x,which has a great effect on the energy production process under bacterial anaerobic conditions.The DHAK reaction is also related to the metabolic process of ATP.These reactions with large differential metabolic fluxes merit further research.Additionally,to provide a strategy to address photocatalysis-resistant mutant bacteria,a metabolic compensation analysis was also performed.The metabolic compensation analysis results provided suggestions for a combined method that can effectively combat resistant bacteria.This method could also be used to explore the mechanisms of drug resistance in other microorganisms.展开更多
Titania (TiO2) induced photocatalysis has been widely investigated and applied as a disinfection strategy in many industrial and clinical applications. Reactive oxygen species (ROS), including hydroxyl radicals (&...Titania (TiO2) induced photocatalysis has been widely investigated and applied as a disinfection strategy in many industrial and clinical applications. Reactive oxygen species (ROS), including hydroxyl radicals (&8226OH), superoxide radicals () and hydrogen peroxide (H2O2), generated in the photocatalytic reaction process are considered to be the active components prompting the bactericidal effect. In the present work, the kinetics of photocatalytic inactivation of Staphylococcus epidermidis and specific contributions of •OH, and H2O2 to the bactericidal process were studied using two disinfection settings sutilizing photocatalytic resin-TiO2 nanocomposite surfaces and suspended TiO2 nanoparticles, respectively. In antibacterial tests against S. epidermidis with a layer of bacterial suspension on the resin-TiO2 surfaces, H2O2 was found to be the most efficient ROS component contributing to the antibacterial effect. Disinfection kinetics showed a two-step behavior with an initial region having a lower disinfection rate followed by a higher rate region after 10 min of UV irradiation. By contrast, in antibacterial tests with suspended bacteria and photocatalytic TiO2 nanoparticles, •OH and H2O2 showed equal significance in the bacterial inactivation having a typical Chick-Watson disinfection kinetics behavior with a steady disinfection rate. The results contribute to the understanding of the bactericidal mechanism and kinetics of photocatalytic disinfection that are essential for designing specific antibacterial applications of photocatalytic materials.展开更多
基金supported by the National Key R&D Project(No.2017YFD0200506)the Fundamental Research Funds for the Central Universities(No.2662018JC035)。
文摘Photocatalytic disinfection has long been used to combat pathogenic bacteria.However,the specific mechanism underlying photocatalytic disinfection and its corresponding targets remain unclear.In this study,an analysis of the potential mechanism underlying photocatalytic disinfection was performed based on integrated metabolic networks and transcriptional data.Two sets of RNA-seq data(wild type and a photocatalysis-resistant mutant mediated by titanium dioxide(TiO2))were processed to constrain the genome scale metabolic models(GSMM)of E.coli.By analyzing the metabolic network,the differential metabolic flux of every reaction was computed in constrained GSMM,and several significantly differential metabolic fluxes in reactions were extracted and analyzed.Most of these reactions were involved in the transmembrane transport of substances and occurred on the inner membrane or were an important component of the cell membrane.These results,which are consistent with the reported information,validated our analysis process.In addition,our work also identified other new and valuable metabolic pathways,such as the reaction ALCD2x,which has a great effect on the energy production process under bacterial anaerobic conditions.The DHAK reaction is also related to the metabolic process of ATP.These reactions with large differential metabolic fluxes merit further research.Additionally,to provide a strategy to address photocatalysis-resistant mutant bacteria,a metabolic compensation analysis was also performed.The metabolic compensation analysis results provided suggestions for a combined method that can effectively combat resistant bacteria.This method could also be used to explore the mechanisms of drug resistance in other microorganisms.
基金The Carl Trygger Foundation,The Goran Gustafsson Foundation,The Swedish Research Council,Vinnova and The Swedish Foundation for Strategic Research for financially supporting this work
文摘Titania (TiO2) induced photocatalysis has been widely investigated and applied as a disinfection strategy in many industrial and clinical applications. Reactive oxygen species (ROS), including hydroxyl radicals (&8226OH), superoxide radicals () and hydrogen peroxide (H2O2), generated in the photocatalytic reaction process are considered to be the active components prompting the bactericidal effect. In the present work, the kinetics of photocatalytic inactivation of Staphylococcus epidermidis and specific contributions of •OH, and H2O2 to the bactericidal process were studied using two disinfection settings sutilizing photocatalytic resin-TiO2 nanocomposite surfaces and suspended TiO2 nanoparticles, respectively. In antibacterial tests against S. epidermidis with a layer of bacterial suspension on the resin-TiO2 surfaces, H2O2 was found to be the most efficient ROS component contributing to the antibacterial effect. Disinfection kinetics showed a two-step behavior with an initial region having a lower disinfection rate followed by a higher rate region after 10 min of UV irradiation. By contrast, in antibacterial tests with suspended bacteria and photocatalytic TiO2 nanoparticles, •OH and H2O2 showed equal significance in the bacterial inactivation having a typical Chick-Watson disinfection kinetics behavior with a steady disinfection rate. The results contribute to the understanding of the bactericidal mechanism and kinetics of photocatalytic disinfection that are essential for designing specific antibacterial applications of photocatalytic materials.
