The aim of this research was to detect the N-acyl homoserine lactones (AHLs) production and QseB/C gene of Aeromonas hydrophila. We analyzed the potentials of these isolates of Aeromonas hydrophila in causing biofilm ...The aim of this research was to detect the N-acyl homoserine lactones (AHLs) production and QseB/C gene of Aeromonas hydrophila. We analyzed the potentials of these isolates of Aeromonas hydrophila in causing biofilm formation, hemolysis, protease, and lipase. The antibiotic susceptibility of the 15 Aeromonas hydrophila isolates was also investigated. The detection of AHLs was carried out using the Chromobacterium violaceum strain CV026 as biosensors. The isolated strains were tested for the reaction of C. violaceum CV026 by cross-streaking on an agar plate. Production of AHLs was determined by the diffusing via the agar plates and the tinge of the biosensor strains. All isolated strains produced AHLs. A polymerase chain reaction (PCR) showed the isolated strains had qseB and qseC genes. Susceptibility tests of A. hydrophila isolates were administered against 25 different antibiotic disks representing 12 classes of antibiotics. The strains were highly resistant to β-Lactam with 96.7% showing resistibility, whereas 97.7% susceptibility was found towards Aminoglycoside class of the antibiotic used. 60% showed intermediate resistant to Polypeptide. 100% of the strains showed no resistant to Aminoglycoside, Polypeptide, Monobactam, and Carbapenems class of antibiotics. Each of the isolates was found to be associated with at least one virulent factor. Our results clearly demonstrated that there is a presence of QseB/C genes in A. hydrophila and also produces AHLs molecule and virulence factors. The investigated isolates showed the pathogenic potential of Aeromonas hydrophila which makes it a serious threat to public health.展开更多
The aim of this work was to inhibit biofilm formation by taking advantages of bacterial surface display technology in combination with cell membrane chromatography.A recombinant protein INPAidH was constructed by fusi...The aim of this work was to inhibit biofilm formation by taking advantages of bacterial surface display technology in combination with cell membrane chromatography.A recombinant protein INPAidH was constructed by fusing a quorum signal hydrolase AidH to the C-terminus of the ice nucleation protein(INP).Expression of INP-AidH was achieved on E.coli cell surface at an expression level of 30%of total membrane proteins.Activity of INP-AidH on cell membranes was confirmed in degrading the quorum signal C6-HSL as well as inhibiting bacterial biofilm.Immobilization of INP-AidH anchored cell membranes on silica gel particles was facilitated by taking advantages of cell membrane chromatography.The functionalized silica gel particles also exhibit activities in degrading C6-HSL and inhibiting bacterial biofilm.This article presents a new approach to prevent biofilm formation of silica-based materials.展开更多
The slow growth rate of autotrophic bacteria and regulation of biofilm thickness are critical factors that limit the development of a hydrogen-based membrane biofilm reactor(H_(2)-MBfR).The acylhomoserine lactone(AHL)...The slow growth rate of autotrophic bacteria and regulation of biofilm thickness are critical factors that limit the development of a hydrogen-based membrane biofilm reactor(H_(2)-MBfR).The acylhomoserine lactone(AHL)mediated quorum sensing(QS)system is a crucial mechanism regulating biofilm behavior.However,the AHLs that promote biofilm formation in autotrophic denitrification systems and their underlying mechanisms,remain unclear.This study explored the impact of AHLmediated QS signaling molecules on biofilm development in H_(2)-MBfR.This study revealed that C_(14)-HSL and C_(4)-HSL are potential signaling molecules that enhanced biofilm formation in long-term stable operating H_(2)-MBfR.Subsequent short-term experiments with C_(14)-HSL and C_(4)-HSL confirmed their ability to increase bacterial adhesion to carrier surfaces by promoting the production of extracellular polymeric substances(EPS).Functional gene annotation indicated that exogenous C_(14)-HSL and C_(4)-HSL increased the abundance of signal transduction(increased by 0.250%–0.375%),strengthening the inter bacterial QS response while enhancing cell motility(increased by 0.24%and 0.21%,respectively)and biological adhesion(increased by 0.044%and 0.020%,respectively),thereby accelerating the initial bacterial attachment to hollow fiber membranes and facilitating biofilm development.These findings contribute to the understanding of microbial community interactions in H_(2)-MBfRs and provide novel approaches for biofilm management in wastewater treatment systems.展开更多
The effects of different species and concentrations’signal molecules on aerobic activated sludge system were investigated through batch experiments.Results showed that the fastest NH^(+)_(4)-N oxidization rate and th...The effects of different species and concentrations’signal molecules on aerobic activated sludge system were investigated through batch experiments.Results showed that the fastest NH^(+)_(4)-N oxidization rate and the most extracellular polymeric substances(EPS)secretion were obtained by adding 5 nmol/L N-hexanoyl-l-homoserine lactone(C_(6)-HSL)into the aerobic activated sludge.Further study investigated the correlation among N-acyl-homoserine lactones-mediated quorum sensing(AHLs-mediated QS),nutrient removal performances and microbial communities with the long-term addition of 5 nmol/L C_(6)-HSL.It was found that C_(6)-HSL-manipulation could enhance the stability and optimize the decontamination performance of aerobic granular sludge(AGS)system.Microbial compositions considerably shifted with long-term C_(6)-HSL-manipulation.Exogenous C_(6)-HSL-manipulation inhibited quorum quenching-related(QQ-related)activities and enhanced QS-related activities during the stable period.The proposed C_(6)-HSL-manipulation might be a potential technology to inhibit the growth of harmful bacteria in AGS,which could provide a theoretical foundation for the realization of more stable biological wastewater treatments.展开更多
文摘The aim of this research was to detect the N-acyl homoserine lactones (AHLs) production and QseB/C gene of Aeromonas hydrophila. We analyzed the potentials of these isolates of Aeromonas hydrophila in causing biofilm formation, hemolysis, protease, and lipase. The antibiotic susceptibility of the 15 Aeromonas hydrophila isolates was also investigated. The detection of AHLs was carried out using the Chromobacterium violaceum strain CV026 as biosensors. The isolated strains were tested for the reaction of C. violaceum CV026 by cross-streaking on an agar plate. Production of AHLs was determined by the diffusing via the agar plates and the tinge of the biosensor strains. All isolated strains produced AHLs. A polymerase chain reaction (PCR) showed the isolated strains had qseB and qseC genes. Susceptibility tests of A. hydrophila isolates were administered against 25 different antibiotic disks representing 12 classes of antibiotics. The strains were highly resistant to β-Lactam with 96.7% showing resistibility, whereas 97.7% susceptibility was found towards Aminoglycoside class of the antibiotic used. 60% showed intermediate resistant to Polypeptide. 100% of the strains showed no resistant to Aminoglycoside, Polypeptide, Monobactam, and Carbapenems class of antibiotics. Each of the isolates was found to be associated with at least one virulent factor. Our results clearly demonstrated that there is a presence of QseB/C genes in A. hydrophila and also produces AHLs molecule and virulence factors. The investigated isolates showed the pathogenic potential of Aeromonas hydrophila which makes it a serious threat to public health.
基金Funded by the National Natural Science Foundation of China(No.31771032)。
文摘The aim of this work was to inhibit biofilm formation by taking advantages of bacterial surface display technology in combination with cell membrane chromatography.A recombinant protein INPAidH was constructed by fusing a quorum signal hydrolase AidH to the C-terminus of the ice nucleation protein(INP).Expression of INP-AidH was achieved on E.coli cell surface at an expression level of 30%of total membrane proteins.Activity of INP-AidH on cell membranes was confirmed in degrading the quorum signal C6-HSL as well as inhibiting bacterial biofilm.Immobilization of INP-AidH anchored cell membranes on silica gel particles was facilitated by taking advantages of cell membrane chromatography.The functionalized silica gel particles also exhibit activities in degrading C6-HSL and inhibiting bacterial biofilm.This article presents a new approach to prevent biofilm formation of silica-based materials.
基金support of this work by the Guangxi Natural Science Foundation(China)(No.2022GXNSFFA035033)the National Natural Science Foundation of China(Grant No.51878197)the Research funds of the Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control(China)(No.2301Z003).
文摘The slow growth rate of autotrophic bacteria and regulation of biofilm thickness are critical factors that limit the development of a hydrogen-based membrane biofilm reactor(H_(2)-MBfR).The acylhomoserine lactone(AHL)mediated quorum sensing(QS)system is a crucial mechanism regulating biofilm behavior.However,the AHLs that promote biofilm formation in autotrophic denitrification systems and their underlying mechanisms,remain unclear.This study explored the impact of AHLmediated QS signaling molecules on biofilm development in H_(2)-MBfR.This study revealed that C_(14)-HSL and C_(4)-HSL are potential signaling molecules that enhanced biofilm formation in long-term stable operating H_(2)-MBfR.Subsequent short-term experiments with C_(14)-HSL and C_(4)-HSL confirmed their ability to increase bacterial adhesion to carrier surfaces by promoting the production of extracellular polymeric substances(EPS).Functional gene annotation indicated that exogenous C_(14)-HSL and C_(4)-HSL increased the abundance of signal transduction(increased by 0.250%–0.375%),strengthening the inter bacterial QS response while enhancing cell motility(increased by 0.24%and 0.21%,respectively)and biological adhesion(increased by 0.044%and 0.020%,respectively),thereby accelerating the initial bacterial attachment to hollow fiber membranes and facilitating biofilm development.These findings contribute to the understanding of microbial community interactions in H_(2)-MBfRs and provide novel approaches for biofilm management in wastewater treatment systems.
文摘The effects of different species and concentrations’signal molecules on aerobic activated sludge system were investigated through batch experiments.Results showed that the fastest NH^(+)_(4)-N oxidization rate and the most extracellular polymeric substances(EPS)secretion were obtained by adding 5 nmol/L N-hexanoyl-l-homoserine lactone(C_(6)-HSL)into the aerobic activated sludge.Further study investigated the correlation among N-acyl-homoserine lactones-mediated quorum sensing(AHLs-mediated QS),nutrient removal performances and microbial communities with the long-term addition of 5 nmol/L C_(6)-HSL.It was found that C_(6)-HSL-manipulation could enhance the stability and optimize the decontamination performance of aerobic granular sludge(AGS)system.Microbial compositions considerably shifted with long-term C_(6)-HSL-manipulation.Exogenous C_(6)-HSL-manipulation inhibited quorum quenching-related(QQ-related)activities and enhanced QS-related activities during the stable period.The proposed C_(6)-HSL-manipulation might be a potential technology to inhibit the growth of harmful bacteria in AGS,which could provide a theoretical foundation for the realization of more stable biological wastewater treatments.
