Listeriosis is caused by Listeria monocytogenes(LM) and is currently considered to be one of the leading food-borne diseases worldwide, with mortality rate of 20%~30%. Currently, detection methods for LM are time-cons...Listeriosis is caused by Listeria monocytogenes(LM) and is currently considered to be one of the leading food-borne diseases worldwide, with mortality rate of 20%~30%. Currently, detection methods for LM are time-consuming with low sensitivity, and delayed detection results. SYTO9 has a high affinity for DNA and exhibits enhanced fluorescence upon binding. Therefore, this study used SYTO9 staining and image processing to develop a rapid loop mediated isothermal amplification(LAMP) detection method for LM. Smartphone was successfully used for detecting the color change in different concentrations of LM. Besides, the optimized LAMP reaction temperature was 63 °C by color identification, and the limit of detection for LM was 6 copies/μL in the green channel. So, the developed method, based on image processing, is simple, sensitive and rapid, which provides a new idea and method for rapid detection of LM and other food-borne bacterial pathogens.展开更多
Flow cytometry （FCM） has been widely used in multi-parametric assessment of cells in various research fields, especially in environmental sciences. This study detected the metabolic activity of Escherichia coli and ...Flow cytometry （FCM） has been widely used in multi-parametric assessment of cells in various research fields, especially in environmental sciences. This study detected the metabolic activity of Escherichia coli and Staphylococcus aureus by using an FCM method based on 5-cyano-2,3-ditolyltetrazolium chloride （CTC）; the accuracy of this method was enhanced by adding SYTO 9 and 10% R2A broth. The disinfection effects of chlorine, chloramine, and UV were subsequently evaluated by FCM methods. Chlorine demonstrated stronger and faster destructive effects on cytomembrane than chloramine, and nucleic acids decomposed afterwards. The metabolic activity of the bacteria persisted after the cytomembmnewas damaged as detected using CTC. Low-pressure （LP） UV or medium-oressure （MP） UV treatments exerted no significant effects on membrane permeability. The metabolic activityof the bacteria decreased with increasing UV dosage, and MP-UV was a stronger inhibitor of metabolic activity than LP-UV. Furthermore, the membrane of Gram-positive S. aureus was more resistant to chlorine/chloramine than that of Gram-negative E. coil In addition, S. aureus showed higher resistance to UV irradiation than E. coli.展开更多
基金supported by the grant from the National Natural Science Foundation of China (Nos. 61901168, 8200240581902153)+1 种基金Zhuzhou Innovative City Construction Project(No. 2020–020)China Postdoctoral Science Foundation (No.2018M630498)。
文摘Listeriosis is caused by Listeria monocytogenes(LM) and is currently considered to be one of the leading food-borne diseases worldwide, with mortality rate of 20%~30%. Currently, detection methods for LM are time-consuming with low sensitivity, and delayed detection results. SYTO9 has a high affinity for DNA and exhibits enhanced fluorescence upon binding. Therefore, this study used SYTO9 staining and image processing to develop a rapid loop mediated isothermal amplification(LAMP) detection method for LM. Smartphone was successfully used for detecting the color change in different concentrations of LM. Besides, the optimized LAMP reaction temperature was 63 °C by color identification, and the limit of detection for LM was 6 copies/μL in the green channel. So, the developed method, based on image processing, is simple, sensitive and rapid, which provides a new idea and method for rapid detection of LM and other food-borne bacterial pathogens.
文摘Flow cytometry （FCM） has been widely used in multi-parametric assessment of cells in various research fields, especially in environmental sciences. This study detected the metabolic activity of Escherichia coli and Staphylococcus aureus by using an FCM method based on 5-cyano-2,3-ditolyltetrazolium chloride （CTC）; the accuracy of this method was enhanced by adding SYTO 9 and 10% R2A broth. The disinfection effects of chlorine, chloramine, and UV were subsequently evaluated by FCM methods. Chlorine demonstrated stronger and faster destructive effects on cytomembrane than chloramine, and nucleic acids decomposed afterwards. The metabolic activity of the bacteria persisted after the cytomembmnewas damaged as detected using CTC. Low-pressure （LP） UV or medium-oressure （MP） UV treatments exerted no significant effects on membrane permeability. The metabolic activityof the bacteria decreased with increasing UV dosage, and MP-UV was a stronger inhibitor of metabolic activity than LP-UV. Furthermore, the membrane of Gram-positive S. aureus was more resistant to chlorine/chloramine than that of Gram-negative E. coil In addition, S. aureus showed higher resistance to UV irradiation than E. coli.
