Objective To evaluate the osteocompatibility of poly(D,L lactic acid)/ hydroxyapatite/decalcified bone matrix (PDLLA/HA/DBM) and to compare the osteocompatibility with that of PDLLA and DBM. Methods The isolated human osteoblasts from the femoral head of patients were inoculated onto PDLLA/HA/DBM, PLA, and DBM. The interface between biomaterial and osteoblasts was investigated with phase contrast microscope and scanning electron microscope. Results Osteoblasts were attached tightly to the surface of biomaterial with an arched structure and had normal morphology. The extracellular collagenous matrix covered the surface of biomaterial and packed the granules of biomaterial completely. Conclusion PDLLA/HA/DBM can form osteointegrated interface at the early stage with good biocompability.

Objective To study the effects of PDLLA/HA/DBMV biomaterials on cell proliferation by comparison of polyactic acid (PDLLA) and decalcified bone matrix (DBM) so as to evaluate the biocompatibility of the biomaterials at the cell level. Methods The isolated third generation human fetal osteoblasts (suspension, 3.5?10 5/ml) were inoculated onto the biomaterials of PDLLAHA/DBM, PDLLA, and DBM for 1, 2, 3, 5, and 7 d. Proliferation rates of cells on different materials were determined by flow cytometry. Results The osteoblast proliferation rate on PDLLA/HA/DBM was higher than that on PLA and DBM. Conclusion PDLLA/HA/DBM is compatible for the growth of osteoblasts.

Objective To investigate the self-assembly and cellular localization patterns of fila-mentous temperature-sensitive protein Z (FtsZ) in Escherichia coli (E.coli) strains by using FtsZP74R, FtsZG77D and FtsZA81R mutants.Methods YFP or His labeled FtsZ proteins and the plasmids of FtsZ mu-tants were constructed by using molecular clone and site-directed mutagenesis methods.The targeted proteins were purified by affinity chromatography.FL37(△ftsZ-Cat) strains were constructed via linear DNA homol-ogous recombination.Living cell imaging was performed to observe the cellular localization patterns of FtsZ protein and its mutants in E.coli strains.The interactions between FtsZ-FtsZ/FtsZ mutants were examined by coi-mmunoprecipitation assay . The polymerization properties of FtsZ mutants were analyzed by light scattering.The activities of GTPase were monitored by using high performance liquid chromatography.Re-sults The P74, G77 and A81 amino acids were respectively replaced by different polar amino acids to change the amphipathicity of the helix within the domain of FtsZ ( 74-82 ) .The YFP-labeled FtsZP74R , FtsZG77D and FtsZA81R mutants failed to assemble into functional Z-ring structure in E.coli strains.The inter-actions between FtsZ protein and its mutants were weakened or completely disappeared.In addition, in vitro experiments showed that P74R, G77D and A81R mutations caused a decrease in the polymerization efficien-cy of FtsZ monomer.The activity of GTPase was significantly decreased in the FtsZA81R mutant. Conclusion The P74, G77 and A81 were critical amino acids in the function and assembly of FtsZ protein in E.coli strains.Moreover, A81 amino acid regulated the lateral interaction of FtsZ monomer and the activity of GTPase.