1.Rapid detection of Salmonella by enzymatic recombinase amplification combined with lateral flow chromatography
NIE Yanni ; YAN Meiying ; SONG Yanyan
Journal of Preventive Medicine 2023;35(12):1102-1104
Objective:
To establish a rapid detection method for Salmonella based on the combination of enzymatic recombinase amplification (ERA) and lateral flow chromatography (LF), so as to provide technical support for the on-site detection of Salmonella.
Methods:
Specific ERA primers and probes were designed based on the highly conserved flagella gene fimY in Salmonella. The primers were screened using capillary electrophoresis, and the probes were designed according to the amplification range of the screened primers. The amplification temperature and time were optimized to establish the amplification method, and the product was detected using LF strips. A standard strain of Salmonella was used to verify the sensitivity, 10 other gut bacteria were used to to verify the specificity and sensitivity, and the nucleic acid of the actual Salmonella strains was amplified to verify the detectability.
Results:
After screening for Salmonella-specific primers using capillary electrophoresis, the minimum detection concentration was 5 copies/μL under the amplification temperature of 37 ℃ and reaction time of 20 minutes. This method had a positive amplification result for Salmonella nucleic acid, and the amplification results of 10 other gut bacteria were all negative, with good specificity.
Conclusion
This method provides a possibility for on-site point of care testing of Salmonella infection.
2.Effects of naloxone at different doses on neurons of cerebral cortex in rats
Chaowu LI ; Mingyi TU ; Suming ZHANG ; Hailing NIE ; Yanni MA ; Yong CHENG ; Gaofeng MAO ; Huang FANG ; Jin ZHANG
Chinese Journal of Tissue Engineering Research 2005;9(13):204-205
BACKGROUND: Naloxone has a significant arousal effect on many types of comas. It is usually believed that this is because its inhibition on endogenous opioid peptides. But depth of coma is not necessarily positively correlated to endorphin (EP).OBJECTIVE: Based on existing findings on direct stimulating effect of naloxone on cerebral cortex, further studies need to be done to explore whether it is dose-dependent or not.DESIGN: Single-factor design based on cells.SETTING: Neurology department in a university hospital and the neurology department in a hospital of a military medical university of Chinese PLA.MATERIALS: This study was completed in the Laboratory Center of Tongji Medical College, Huazhong University of Science and Technology. Thirty healthy new born Wistar rats, regardless of their gender, aging 8 - 12 days and weighing 150 -250 g, were selected.METHODS: The experiment was performed at room temperature. The perfusion slot were placed on the microscope stage, and cells with smooth surfaces, triangle or pyramidal shapes, strong refraction and more than one neurites were selected for patch clamp experiment. Patch clamp whole-cell recording technique was used to measure the pyramidal cells of the frontal lobe immediately after separated from the Wistar rats, and to investigate the fluctuations of their membrane potential of cerebral cortex neurons and the frequencies of their spontaneous electric activities after administration of naloxone at different doses.MAIN OUTCOME MEASURES: The neural excitatory reaction rate, depolarization amplitude and increasing rate of spontaneous electric activities after administration of different doses of naloxone were selected as main outcome measurements.RESULTS: The excitatory reaction rates of cerebral cortex neurons immediately after separation to doses of naloxone(100, 50, 10, 1, 0. 1 μmol/L)were 83%, 67%, 86%, 71% and 33%; while the depolarization amplitude of them were 9. 8, 9.6, 8.4, 5.2 and 1. 3 mV respectively; and the corresponding spontaneous electric activity were increased by 587% , 375% ,291%, 125% and 69%.CONCLUSION: Naloxone can induce excitatory reactions in cerebral cortex neurons directly, and the reactions have proved to be dose-dependent.