ABSTRACT
Objective:To determine the optimal condition for mouse embryonic stem cells (mESC) culture with stirred bioreactor,and to develop a method for mass production of embryoid bodies (EB). Methods:The different initial cell concentrations of mESC and the initial stirring speed of bioreactor were investigated to determine the optimal condition for EB formation. Induced by ascorbic acid,the differentiation of EBs formed in stirred bioreactor into cardiomyocytes was compared with EBs formed in Petri dish. Immunofluorescence staining and RT-PCR were used to identify the cardiomyocytes derived from mESC. Results:The formation of a large number of uniform relatively EBs was achieved in stirred bioreactor when mESC were seeded initially with 1?105~3?105 cells/ml and stirring speed was set to 15~30r/min. Most of cells in the EBs formed in bioreactor were viable. EBs produced in bioreactor differentiated into cardiomyocytes more efficiently compared with EBs from Petri dish. The cardiac specific genes were expressed in ESC-derived cardiomyocytes. Conclusions:Stirred bioreactor culture could enhance the efficiency of EB formation and differentiation into cardiomyocytes,which may be a more ideal culture system for EB formation.
ABSTRACT
In MAST (mRNA accessible site tagging),the DNA tags from synthesized library were employed for identifying mRNA accessible sites. A large number of tags were amplified and subcloned for sequencing to verify mRNA binding profiles. A PCR was designed by using one primer which bridges over the tag terminal sequences. In PCR reaction DNA tag fragments were concatemerized by a bridge primer in reaction cycles. The concatemerized tag fragments were subcloned and sequenced. Dozens of the concatemerized sequences contained thousands tags. The PCR was a simple,effective way which for sequencing tags in a high through put manner.