creening of foodborne pathogens is important to prevent contaminated foods from their supply chains.n this study, a portable detection device was developed for rapid, sensitive and simple detection of viable almonella...creening of foodborne pathogens is important to prevent contaminated foods from their supply chains.n this study, a portable detection device was developed for rapid, sensitive and simple detection of viable almonella using a finger-actuated microfluidic chip and an improved recombinase aided amplification (RAA) assay. Improved propidium monoazide(PMAxx) was combined with RAA to enable this device to distinguish viable bacteria from dead ones. The modification of PMAxx into dead bacteria, the magnetic xtraction of nucleic acids from viable bacteria and the RAA detection of extracted nucleic acids were performed using the microfluidic chip on its supporting device by finger press-release operations. The fluorescent signal resulting from RAA amplification of the nucleic acids was collected using a USB camera nd analyzed using a self-developed smartphone App to quantitatively determine the bacterial concenration. This device could detect Salmonella typhimurium in spiked chicken meats from 1.3 × 10^(2) CFU/m L o 1.3 × 10^(7) CFU/m L in 2 h with a lower detection limit of 130 CFU/m L, and has shown its potential for on-site detection of foodborne pathogens.展开更多
Axonal tracing is useful for detecting optic nerve injury and regeneration,but many commonly used methods cannot be used to observe axoplasmic flow and synaptic transmission in vivo.Manganese（Mn^2＋）-enhanced magnet...Axonal tracing is useful for detecting optic nerve injury and regeneration,but many commonly used methods cannot be used to observe axoplasmic flow and synaptic transmission in vivo.Manganese（Mn^2＋）-enhanced magnetic resonance imaging（MEMRI） can be used for in vivo longitudinal tracing of the visual pathway.Here,we explored the dose response and time course of an intravitreal injection of Mn Cl2 for tracing the visual pathway in rabbits in vivo using MEMRI.We found that 2 m M Mn Cl2 enhanced images of the optic nerve but not the lateral geniculate body or superior colliculus,whereas at all other doses tested（5–40 m M）,images of the visual pathway from the retina to the contralateral superior colliculus were significantly enhanced.The images were brightest at 24 hours,and then decreased in brightness until the end of the experiment（7 days）.No signal enhancement was observed in the visual cortex at any concentration of Mn Cl2.These results suggest that MEMRI is a viable method for temporospatial tracing of the visual pathway in vivo.Signal enhancement in MEMRI depends on the dose of Mn Cl2,and the strongest signals appear 24 hours after intravitreal injection.展开更多
基金funded by National Natural Science Foundation of China (No. 32071899)Walmart Foundation (No. UA2020– 154)。
文摘creening of foodborne pathogens is important to prevent contaminated foods from their supply chains.n this study, a portable detection device was developed for rapid, sensitive and simple detection of viable almonella using a finger-actuated microfluidic chip and an improved recombinase aided amplification (RAA) assay. Improved propidium monoazide(PMAxx) was combined with RAA to enable this device to distinguish viable bacteria from dead ones. The modification of PMAxx into dead bacteria, the magnetic xtraction of nucleic acids from viable bacteria and the RAA detection of extracted nucleic acids were performed using the microfluidic chip on its supporting device by finger press-release operations. The fluorescent signal resulting from RAA amplification of the nucleic acids was collected using a USB camera nd analyzed using a self-developed smartphone App to quantitatively determine the bacterial concenration. This device could detect Salmonella typhimurium in spiked chicken meats from 1.3 × 10^(2) CFU/m L o 1.3 × 10^(7) CFU/m L in 2 h with a lower detection limit of 130 CFU/m L, and has shown its potential for on-site detection of foodborne pathogens.
基金supported by a grant from the National Basic Research Program of China(973 Program)No.2011CB707506+1 种基金the Seed Fund from the Peking University Third Hospital of China,No.YZZ08-9-13the Linghu Fund from the Peking University Third Hospital of China,No.64508-01
文摘Axonal tracing is useful for detecting optic nerve injury and regeneration,but many commonly used methods cannot be used to observe axoplasmic flow and synaptic transmission in vivo.Manganese（Mn^2＋）-enhanced magnetic resonance imaging（MEMRI） can be used for in vivo longitudinal tracing of the visual pathway.Here,we explored the dose response and time course of an intravitreal injection of Mn Cl2 for tracing the visual pathway in rabbits in vivo using MEMRI.We found that 2 m M Mn Cl2 enhanced images of the optic nerve but not the lateral geniculate body or superior colliculus,whereas at all other doses tested（5–40 m M）,images of the visual pathway from the retina to the contralateral superior colliculus were significantly enhanced.The images were brightest at 24 hours,and then decreased in brightness until the end of the experiment（7 days）.No signal enhancement was observed in the visual cortex at any concentration of Mn Cl2.These results suggest that MEMRI is a viable method for temporospatial tracing of the visual pathway in vivo.Signal enhancement in MEMRI depends on the dose of Mn Cl2,and the strongest signals appear 24 hours after intravitreal injection.
