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Objective To explore the effect of different factors on strengthening the tissue culture seedlings and roots of Dendranthema morifolium ( Ramat) Tzvel. cv. Gongju, so as to provide experimental basis for establishing an in-vitro rapid propagation system of Dendranthema morifolium. Methods The experiment took Dendranthema morifolium ( Ramat) Tzvel. cv. Gongju tissue culture seedling as the studying object. By using tissue culture technology, different additives were added into the MS medium. Results In the seedling-strengthening culture medium, 150 mL/L of macro-element was beneficial to the growth of tissue culture seedlings of Dendranthema morifolium ( Ramat) Tzvel. cv. Gongju. The culture medium with 100 g/L of coconut milk added could obviously promote the growth of Dendranthema morifolium ( Ramat) Tzvel. cv. Gongju tissue culture seedlings. And activated carbon added to the rooting culture medium could induce the formation of tissue culture root system of Dendranthema morifolium ( Ramat) Tzvel. cv. The addition of α-naphthaleneacetic acid ( NAA) and indolebutyric acid ( IBA) at certain concentrations could promote the amount and the growth of the roots. Conclusion The tissue culture seedlings of Dendranthema morifolium ( Ramat) Tzvel. cv. Gongju are boosted by increasing the amount of macro-element, reducing the concentration of agar in the culture medium and adding coconut milk and growth hormones to the culture medium. The optimal rooting culture medium is a compound of 1/2MS, NAA 0.05 mg/L and IBA 0.05 mg/L.
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BACKGROUND:Notch singling pathway is very important for cellproliferation and differentiation, but its role is stil unknown during chondrogenesis of human umbilical cord mesenchymal stem cells. OBJECTIVE:To investigate the effect of N-[N-(3,5-difluorophenacetyl-L-alanyl)]-(S)-phenylglycinet-butyl ester (DAPT) on inducing human umbilical cord mesenchymal stem celldifferentiation into chondrocytes. METHODS:Human umbilical cord mesenchymal stem cells were isolated from human umbilical cord, then were induced to differentiate into chondrocytes. There were four experimental groups:non-induced group, high-glucose Dulbecco’s modified Eagle’s medium containing 5%fetal bovine serum and 1%double antibody;induced group, induced medium containing 6.25 mg/L insulin, 6.25 mg/L transferrin, 10μg/L transforming growth factor beta 1, 0.1μmol/L dexamethasone, 50 mg/L vitamin C, 5%fetal bovine serum and 1%double antibody;dimethyl sulfoxide group, induced medium containing 0.1%dimethyl sulfoxide;DAPT group, induced medium containing 5μmol/L DAPT. RESULTS AND CONCLUSION:After chondrogenic induction, the morphology of human umbilical cord mesenchymal stem cells became polygon and positive for toluidine blue and immunofluorescence staining;the expression of Jag-1, PS-1, Notch-1 and Hes-1 decreased significantly (P<0.01). After the addition of DAPT, compared with the induced group, the relative gene expression of Jag-1, PS-1 and Hes-1 decreased markedly (P<0.01), the relative gene expression of Notch-1 decreased obviously as wel (P<0.05), and the contents of proteoglycan and col agen type II proteins decreased significantly (P<0.01). At the same time, the relative gene expression of proteoglycan decreased obviously (P<0.05), and the relative gene expression of col agen type II decreased in part. Notch signaling pathway exists in human umbilical cord mesenchymal stem cells, once chondrogenesis begins, the signaling strength wil decline rapidly. DAPT may prevent human umbilical cord mesenchymal stem cells from differentiating into chondrocytes by Jag-1-Notch-1-Hes-1 pathway.