Objective To construct double expression retroviral vectors targeting chronic myeloid leukemia (CML) b3a2-type mRNA and investigate its effect on the phenotype of K562 cells. Methods The eGFP coding sequence was inserted into the retroviral vector pMSCV-neo to construct pMSCV/GFP, then H1-RNA pol III-based transcription cassettes was subcloned into it to form pMSCV/GFP-H1-BCR/ABL40AS. Two control vectors pMSCV/GFP-H1-BCR/ABL40S & pMSCV/GFP-H1-BCR/ABL80AS were constructed in addition. All these constructions were identified by restriction enzyme analysis and DNA sequencing. After that, the recombinant vectors were transferred into retrovirus packaging cell line PT67 by using lipofectamine2000, and G418 were used to select stable virus-producing cell lines. Viral titer was determined by infection of NIH3T3 cells sequentially. The cell-growth curve was assayed, cell apoptosis was checked with Annexin V-PE/7AAD double staining and flow cytometry analysis after 24-hour infection, the PKR phosphorylation was assayed by Western blotting. Results The plasmids were successfully constructed. Four cell lines, named as PT67-MSCV/GFP, PT67-40as, PT67-40s and PT67-80as were gained by G418 selection, and virus titers were 6.2?10~ 5 , 5.6?10~ 5 , 4.6?10~ 5 and 6.0?10~ 5 CFU/ml respectively. PT67-40as suspensions could induce K562 cell apoptosis by (22.54?3.19)%, significantly different from PT67-MSCV/GFP or PT67-40s (P

Polymerase chain reaction (PCR) is the gold standard for nucleic acid amplification in molecular diagnostics. The PCR includes multiple reaction stages (denaturation, annealing, and extension), and a complicated thermalcycler is required to repetitively provide different temperatures for different stages for 30-40 cycles within at least 1-2 hours. Due to the complicated devices and the long amplification time, it is difficult to adopt conventional PCR in point-of-care testing (POCT). Comparing to conventional PCR, isothermal amplification is able to provide a much faster and more convenient nucleic acid detection because of highly efficient amplification at a constant reaction temperature provided by a simple heating device. When isothermal amplification is combined with microfluidics, a more competent platform for POCT can be established. For example, various diagnosis devices based on isothermal amplification have been used to rapidly and conveniently detect SARS-CoV-2 viruses. This review summarized the recent development and applications of the microfluidics-based isothermal amplification. First, different typical isothermal amplification methods and related detection methods have been introduced. Subsequently, different types of microfluidic systems with isothermal amplification were discussed based on their characteristics, for example, functionality, system structure, flow control, and operation principles. Furthermore, detection of pathogens (e.g. SARS-CoV-2 viruses) based on isothermal amplification was introduced. Finally, the combination of isothermal amplification with other new technologies, e.g. CRISPR, has been introduced as well.
COVID-19/diagnosis* ; Humans ; Microfluidics ; Nucleic Acid Amplification Techniques ; Polymerase Chain Reaction ; SARS-CoV-2/genetics*