Molecular beacon probe was designed based on a specific DNA sequence of Nocardia to PCR detection of thisbacterium.The strains of Nocardia、Gordina and Rhodococcus were inoculated in Brain Heart Infusion Agar medium separately,then the growth condition was observed,DNA was extracted as a template;the molecular beacon probe was designed based on the partial secA 1 gene sequences of Nocardia strains,and the probe was added into the reaction system of real time fluorescence quantitative PCR (RT-PCR),and the fluorescence signal was tested at the end of PCR.Showed that the amplified secA1 gene of Nocardia could produce positive fluorescence signal in RT-PCR,but those of Gordonia and Rhodococcus with control groups showed negative results because of no fluorescence signal.In conclusion as a housekeeping gene,secA1 is an ideal target molecule to identify the actinomycetes strains on the species level in the systematic evolution research,and the technique of fluorescence molecular beacon probe is accurate,rapid and sensitive for detecting the Nocardia strains with secA1 gene.

OBJECTIVETo aimed at the establishment of mouse stably knockout of MYSM1 mesenchymal stem cell(MSC) line C3H10T1/2, and to investigate its immunological capacity of MSC in vitro.

METHODSTo establish the stably transfected MSC cell line by using CRISPR-Cas9 technology. Then the Flow cytometry, quantitative PCR and Western blot were employed to detect whether the MYSM1 have been knockout yet. Furthermore, the immune modulatory effect of MYSM1MSC was tested by addition of MYSM1MSC supernatant into spleen lymphocyte and Foxp3 culture. The mRNA expression of inflammatory cytokines such as interleukin-4, interferon-γ and interleukin-17 were detected by quatitatine PCR.

RESULTSThe expression of MYSM1 was steadily knock out in MSC. In addition, MYSM1MSC showed a stronger inhibitory effect on the expression of inflammatory cytokines. Therefore, the MYSM1 has been stably knocked out in C3H10T1/2.

CONCLUSIONThe mouse stably knockout of MYSM1 mesenchymal stem cells has been successfully established, the knock-out of MYSM1 in MSC can induce more potent immunosuppressive effects on cellular immune reaction in vitro. Our data laid a foundation for the further MSC-based applications in immune related diseases.