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@#ObjectiveTo achieve efficient expression of human serum albumin(HSA)in Chinese hamster ovary(CHO)cells and optimize its culture technology,so as to lay a foundation of the large-scale production of HSA.MethodsThe eukaryotic expression vector of HSA was constructed by gene recombination technology,and then electrotransfected into fully suspended CHO cells. The monoclonal cell lines with stable and high expression of HSA were screened by G418 and limited dilution method. By adding glucose,sodium butyrate and supplementalmedium to the basal medium,the cell culture process was optimized to improve the expression of HSA. Finally,the scale-up culture verification was carried out in a 5 L bioreactor.ResultsThe recombinant expression vector pcDNA3.1-HSA was successfully constructed and expressed in fully suspended CHO cells. After two monoclonal screening,the secondary monoclonal cell lines CHO-rHSA-7H2A9 and CHOrHSA-7H2D12 were obtained with high HSA expression of 29. 37 mg/L and 25. 26 mg/L respectively. The HSA expression level reached about 100. 00 mg/L by optimizing the culture process and wasfinally increased to 166. 16 mg/L in the 5 L bioreactor,which was about 30 times higher than that in the supernatant of the first monoclonal cells.Conclusion The high level expression of HSA in CHO cells was achieved,which laid a foundation of the further large-scale production of HSA in the field of biological products and solving the market supply problems.
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OBJECTIVE: To explore the stability of recombinant human serum albumin and interferon alpha 2b fusion protein for injection. METHODS: According to the testing methods of Ch.P, influencing factors test [high temperature test at (42±2)℃, strong light test at (4 500±500)lx and humidity test at RH of 90%], accelerated test (37 and 25 ℃)and long-term test were carried out according to the technical guidelines of biological stability study. RESULTS: The results of influencing factors test, accelerated test and long-term test showed that temperature had influence on the purity of products. The protein purity decreased with the increase of temperature. Humidity also had influence on the moisture content of products, with little influence on other indicators. Long term stability investigation found that the sample was relatively stable within 24 months and the examined indexes accorded with the quality standard. CONCLUSION: This recombinant protein can be stored at 2-8 ℃ for 24 months.
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@#Objective To investigate whether recombinant human serum albumin (rHSA) can replace traditional B27 as a basic medium for differentiation of human pluripotent stem cells (hPSCs) into cardiomyocytes. Methods hPSCs were seeded at a cell density of 1.2×104/cm2; until up to 75% confluency hPSCs were induced by differentiation medium containing various concentration of rHSA (0, 50, 100, 200 g/L). Light microscope and fluorescence microscope recorded the whole process of stem cells differentiating into myocardium. Flow cytometry was used to detect the cardiac differentiation efficiency at different concentrations of rHSA. Immunofluorescence staining was used to detect the cardiac specific protein α-actinin and troponin T (cTnT) and electron microscope to observe the ultrastructure of human pluripotent stem cell-derived cardiomyocytes (hPSC-CM) and beating rates of hPSC-CMs response to drugs. Results A large number of spontaneous beating cardiomyocytes were observed 9 days after induction and differentition. The percentage of colonies showing beating cardiomyocytes was 60.4% at the concentration of 200 g/L of rice derived-rHSA. Beating cardiomyocytes were α-actinin and cTnT positive. Ultrastructural analysis showed scattered sarcomeres and mitochondrial. hPSC-CMs were dose-dependent on isopropyl adrenaline and verapamil. Conclusion Using such simple media to differentiate hPSCs into functional cardiomyocytes is cost-effective and highly efficient, and can be used in the clinical research.
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Recently the methylotrophic Pichia pastoris,with many advantages such as high expression,stable genetics and protein secretion,has been used extensively as a host expressing heterologous proteins.The optimal seed medium among seven media MM,MD,MGY,BMGY,YMPD,YMPGy and MGyB is BMGY with addition of 4mL/L PTM1 The high density synthesized medium in shake flask culture is as follows: Glycerol 4%(NH 4) 2SO 4 10g/L,CaSO 4 0.93g/L,K 2SO 4 18 2g/L,MgSO 4?7H 2O 14 9g/L,add 0.1mol/L PBS(pH=6 0) to 1 0 liter.The harvested yeast cell optical density (OD 600 ) reached 65 or more after 26 hours cultivation.By analysis of SDS\|PAGE,the results of Pichia pastoris culture by methanol inducement for 72 hours showed that the expression of recombinant human serum albumin had been achieved by methanol inducement after 12 hours,and the mount of targeted protein reached the summit after 24 hours inducement by methanol.The high density synthesized medium in shake flask culture in this experiment,which is similar to the mediums of batch fermentation and batch\|fed fermentation,is benefit to direct the P.pastoris fermentation in the fermentor.