In the teaching reform of genetics,we took the exploration of teaching reform mode in association with constructivism theory."One-center,both-balance,four-strategy combined"and combination of popularized education with elite education were the traits.The effects were favorable through the reform carried out both in theory teaching and experimental teaching.

Focusing on the individual ability and the current domestic higher education,we were trying to set up a new learning pathway,experiential learning.Under performing a"SHU TU TONG GUI"activity series,undergraduates were encouraged to develop their cooperative skill and creativity quality.This exploration was helpful for us to carry out a new higher education mode in the future.

AIM: To get high biological activity of recombinant human bone morphogenetic protein -2 (rhBMP-2) expressed in Escherichia coli by the methods of refolding. METHODS: The rhBMP-2,expressed in Escherichia coli, was washed by Triton X- 100 and further purified by DEAE chromatography.The inclusion bodies were resolved in 8 mol/L urea, and were refolded and dimerized in the redox systems (reduced and oxidized glutathione). Finally, a one - step purification procedure based on the heparin affinity chromatography was implemented. The biological activity of purified rhBMP - 2 were tested by induction of the alkaline phosphatase activity in C2C12 cells. RESULTS: The rhBMP - 2 was expressed in Escherichia coli in a non - active aggregated form of inclusion bodies using a temperature - inducible expression system. The high - purified rhBMP - 2 was obtained in the form of inclusion bodies by several purification courses. The rhBMP - 2 was refolded and dimerized in the redox systems (reduced and oxidized glutathione) and a one - step purification procedure based on the heparin affinity chromatography was implemented to isolate the rhBMP - 2 dimers and monomers. The purified rhBMP - 2 dimers showed the higher biological activity than the commercial rhBMP - 2. CONCLUSIONS: The method achieved the refolding of rhBMP - 2 would be applied to the whole TGF - β superfamily because the BMP - 2 belongs to the superfamily. Meanwhile, the inexpensive,high yield rhBMP - 2 is suitable for clinic application.

AIM: To screen the cytotoxicity of degradable calcium metaphosphate (dCMP) compared with hydroxyapatite (HA). The proliferation and differentiation abilities of human marrow mesenchymal stem cells (MSC) were used to exhibit the cytotoxicity. METHODS: The cell morphology of MSC was analysed after direct contact with dCMP at different time points by scanning electron microscopy analysis. The degradation products of dCMP and HA were analysed with inductively coupled plasma torch and ion chromatography. The cytotoxic effect of degradation products of dCMP was evaluated by FACS, quantitative assay of ALP and ARS, respectively. RESULTS: dCMP enhanced the proliferation of MSC, but didn't interfere the osteogenic differentiation process of MSC and its mineralization. HA inhibited the proliferation of MSC and the mineralization of osteogenic differentiated MSC, while it did not interfere the osteogenic differentiation process of MSC. CONCLUSION: dCMP had a better cytocompatibility with MSC than HA, which might allow for its use as skeleton scaffolds.

AIM: To get high biological activity of recombinant human bone morphogenetic protein-2 (rhBMP-2) expressed in Escherichia coli by the methods of refolding. METHODS: The rhBMP-2, expressed in Escherichia coli, was washed by Triton X-100 and further purified by DEAE chromatography. The inclusion bodies were resolved in 8 mol/L urea,and were refolded and dimerized in the redox systems (reduced and oxidized glutathione). Finally, a one-step purification procedure based on the heparin affinity chromatography was implemented. The biological activity of purified rhBMP-2 were tested by induction of the alkaline phosphatase activity in C2C12 cells. RESULTS: The rhBMP-2 was expressed in Escherichia coli in a non-active aggregated form of inclusion bodies using a temperature-inducible expression system. The high-purified rhBMP-2 was obtained in the form of inclusion bodies by several purification courses. The rhBMP-2 was refolded and dimerized in the redox systems (reduced and oxidized glutathione) and a one-step purification procedure based on the heparin affinity chromatography was implemented to isolate the rhBMP-2 dimers and monomers. The purified rhBMP-2 dimers showed the higher biological activity than the commercial rhBMP-2. CONCLUSIONS: The method achieved the refolding of rhBMP-2 would be applied to the whole TGF-? superfamily because the BMP-2 belongs to the superfamily. Meanwhile, the inexpensive, high yield rhBMP-2 is suitable for clinic application.