ABSTRACT
Objective To study the effects of pulsed electromagnetic fields(PEMFs)of 15Hz and lmT on osteoblast differentiation of bone marrow mesenchymal stem cells.Methods The bone marrow mesenchymal stem cells were isolated and cultured in vitro,the third passage cells were harvested and half of them was exposed to PEMFs,another half exposed to sham PEMFs served as the control.The activity of ALP was measured.And the ex- pression of osteoblast and adipogenesis was measured with the semi-quantitative RT-PCR,adipogenic differentiation was observed with the Oil Red O Staining.Results When compared with the control,PEMFs of 15 Hz and 1 mT significantly increased the activity of ALP(P
ABSTRACT
The regulation of foreign gene expression in Insect-Baculovirus Expression System is very complex. In this report, the effect of 5'-UTR in the expression of hGH gene in cultured Sf9 cells was examined. A 18 bp length in the end of 5'-UTR of hGH (human Growth Hormone, hGH) cDNA including a stem-loop structure was deleted by PCR. The truncated hGH cDNA, delta 1hGH was cloned in pFastBac1, named pFast-Bac-delta 1hGH. After transforming into E. coli. DH10Bac, which have a shuttle vetor-Bacmid, the delta 1hGH was integrated into Bacmid by site-specific transposition, and an expression vector, rBacmid-delta 1hGH DNA was acquired. By transfecting the cultured Sf9 cells with the recombinant expression vector DNA, pure recombinant virus, rAcV-Bac-delta 1hGH was obtained, and hGH gene was expressed. Immuno-blot and Chemiluminescent assay revealed that the expressed hGH had normal immunological activity, the amount of hGH expression level in Sf9 cell supernatant infected with rAcV-Bac-delta 1hGH containing the truncated 5'UTR was four to five times higher than that infected with rAcV-Bac-hGH.