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Objective:To study the difference in the extraction efficiency of the novel coronavirus (2019-nCoV) nucleic acid by using magnetic beads method, centrifugal column method and one-step method.Methods:On March 5, 2021, 10 throat swabs were collected from the staff working in the nucleic acid sampling room in Department of Clinical Laboratory, Affiliated Taikang Xianlin Drum Tower Hospital, Medical School of Nanjing University. The positive quality control samples were mixed into the swabs and used as mock positive samples. The RNA was extracted from simulated positive samples and their diluted samples by using magnetic beads method, centrifugation column method and one-step method. The purity ( A260/ A280 ratio) and concentration of the nucleic acid obtained were measured by micro-uv photometry, and fluorescence quantitative PCR was performed to compare the CT value and extraction efficiency. The three methods were used to extract the simulated weak positive specimens and to compare the difference of CT values after amplification. The measurement data that followed normal distribution were expressed by xˉ±s, the t test was used for comparing in the same group, and single factor analysis of variance was used for comparing among multiple groups. A P value smaller than 0.05 indicated a significant difference. Results:2019-nCoV nucleic acid extracted by magnetic bead method, centrifugal column method and one-step method could amplify positive results. There was no significant difference between the CT value of RNA amplification extracted by magnetic bead method and one-step method ( t=? 0.995 , P=0.376). The CT values of orf1ab gene amplified by centrifugal column method, magnetic bead method and one-step method were 29.28±0.06, 30.82±0.14 and 29.79±0.01 respectively ( F=11.196 , P=0.041). The CT values of E gene were 28.52±0.40, 27.33±0.78 and 27.38±0.13 respectively ( F=3.407, P=0.169). The CT values of N gene were 28.61±1.02, 27.24±0.20 and 27.25±0.47, respectively ( F=2.880 , P=0.020). The CT values of human genes extracted by centrifugal column method, magnetic bead method and one-step method were 19.68±0.36, 20.14±0.06 and 20.58±0.49 respectively, which was statistically significant ( F=4.904, P=0.048). The CT value of amplified human gene was affected by the dilution of human samples twice. The CT value of undiluted samples was smaller than that of diluted samples twice, with a difference of 2.95±0.22, which was statistically significant ( t=?3.025, P=0.039). The extraction time of one-step method, magnetic bead method and centrifugal column method were (15.00±1.50), (20.00±1.50) and (40.00±5.5) min respectively, and the difference was statistically significant ( F=688 , P=0.027). Conclusions:Magnetic bead method, centrifugal column method and one-step method can be used to extract 2019-nCoV nucleic acid, for the centrifugal column method has a higher extraction efficiency than the magnetic bead method and the one-step method. The one-step method is the fastest, followed by the magnetic bead method and the centrifugal column method. A large number of clinical samples can be processed using the magnetic bead method and one-step method. One-step rapid nucleic acid test can also be performed on samples from emergency and fever clinics. It is not recommended to dilute specimens for testing. In order to improve the detection rate, extracting RNA from highly suspected samples with negative initial nucleic acid test by centrifugal column method is suggested.
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Aim To explore the mechanism of E.coli heat-labile enterotoxin B subunit(LTB)as adjuvant by analysis of cellular proteins interacting with LTB. Methods Whole cell proteins were purified from RAW 264.7 cell after treated with LTB or NaCl 12 h, respectively.The cellular proteins were interacted with LTB and the interacting proteins were purified by pull-down assay and identified by mass spectrography.The LTB interaction proteins were conformed with Western blot and immunofluorescence assay.Results 25 LTB interaction proteins were found,and their interaction network was mapped;four proteins (Jup,Dsp,Ddx5 and Vimentin)were indicated to be related with LTB adjuvant activity;immunofluorescence assay indicated that GM130 interacted with LTB,however,Vimentin had no interaction with LTB in vivo.After treated by LTB,the expression of β-actin was upregulated obvi-ously in RAW 264.7 cell,whereras,Hspd1 did not show any change.Conclusions LTB exerts adjuvant activity through binding to GM1 of immune cells,cau-sing endocytosis and transporting to the Golgi apparatus by vesicles.Then LTB might bind to Jup and affect TCF/LEF activity,regulating the expression of Bcl 2, IL-6,and Runx3.The result is promoted T cell and B cell proliferation,differentiation and activation by se-cretion of cytokines and immunoglobulins.
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[ ABSTRACT] AIM:To investigate the effect of DEK downregulation on the apoptosis of gastric carcinoma SGC-7901 cells, and to explore its associations with NF-κB signaling pathway and apoptosis related proteins.METHODS:SGC-7901 cells with different treatments were divided into 3 groups including untreated group, control siRNA group and DEK siRNA group.The expression of DEK at mRNA and protein levels in the SGC-7901 cells was detected by real-time PCR and Western blot.The cell apoptosis was examined by flow cytometry.Furthermore, the activities of caspase-3 and caspase-9 in the SGC-7901 cells were investigated by Caspase-Glo?-3/9 kit.Finally, the expression of key regulatory pro-tein p65 of NF-κB signaling pathway and apoptosis-related proteins Bcl-2 and Bax in the SGC-7901 cells was investigated by Western blot.RESULTS:Compared with untreated group and control siRNA group, the expression of DEK at mRNA and protein levels was significantly downregulated in DEK siRNA group (P<0.05).In addition, the ratios of early phase apoptosis and total apoptosis in DEK siRNA group were markedly higher than those in untreated group and control siRNA group (P<0.05).Most notably, the decrease in p65 and Bcl-2 proteins, increase in Bax protein and the increases of caspase-3 and caspase-9 activities were observed in DEK siRNA group.CONCLUSION:Downregulation of DEK mediates cell apoptosis of gastric carcinoma may be tightly associated with NF-κB signaling pathway.
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BACKGROUND:Classical drug for Parkinson’s disease is levodopa, but long-term application of levodopa can induce complications such as dyskinesias. OBJECTIVE:To observe the effects of levodopa on learning and memory capacities of Parkinson’s disease rats and to study its mechanisms. METHODS:The rat models of Parkinson’s disease were established using 6-hydroxydopamine. The 228 model rats were randomly divided into control group and experimental group. Rats in the experimental group were intraperitoneal y injected with 10, 20 and 30 mg/(kg?d) levodopa for 28 consecutive days. At 1, 3, 5, 7, 14 and 28 days after intraperitoneal injection, we observed the rats’ learning and memory capacities and tested plasma concentration of homocysteine and folic acid. Acetylcholinesterase activities in the rat hippocampus were measured. Hippocampal neurofibril ary tangles were observed using Bielschowsky staining. RESULTS AND CONCLUSION:Increased dose of levodopa and prolonged application time obviously decreased learning and memory capacities in rats (P<0.001), increased plasma homocysteine levels, reduced folic acid levels (P<0.001), diminished acetylcholine esterase activities in the rat hippocampus (P<0.001), and increased neurofibril ary tangles in the rat hippocampus (P=0.000). Results suggested that a large dose of levodopa could significantly decrease the learning and memory capacities, and disease acetylcholine esterase activities, and increase neurofibril ary tangles in hippocampus. Its mechanism possibly associated with the increased plasma concentration of homocysteine.