ABSTRACT
Objective:To purify H5N1 influenza virus concentrate prepared by MDCK cells with a new mixed-mode chromatography medium Capto Core700 and the traditional medium Sepharose 4FF, and to compare the separation and purification efficacy of the two media.Methods:Capto Core700 and Sepharose 4FF were used to purify inactivated H5N1 influenza virus concentrate. The morphology of virus particles in different samples was then observed under a transmission electron microscope. Single radial immunodiffusion (SRID), Folin-Phenol (Lowry) method, double-antibody sandwich ELISA and qPCR were used to detect hemagglutinin, total protein, host cell protein (HCP) and host cell DNA (HCD) before and after purification. The recovery rate of virus antigen and the removal rate of impurities were calculated. The immunogenicity of the viruses purified with different media was analyzed using animal experiments. Difference in the purification efficacy of the two chromatography media was analyzed by t-test. Results:H5N1 influenza viruses purified by Capto Core700 or Sepharose 4FF showed the typical influenza virus morphology under transmission electron microscope. There was no significant difference in the recovery rate of hemagglutinin between the two chromatography media ( P>0.05), but compared with Sepharose 4FF, Capto Core700 had a higher removal rate of impurities (total protein, HCP, HCD) and the difference was statistically significant ( P<0.05). Animal experiments showed that the viruses purified by the two chromatography media had good immunogenicity. Conclusions:Compared with Sepharose 4FF chromatography medium, Capto Core700 could more effectively remove process-related impurities such as HCP, HCD and total protein without affecting the recovery rate of viral antigen. This study provided reference for the development of purification technology in the production of H5N1 influenza virus vaccine in MDCK cells.
ABSTRACT
Objective CARD9 can activate several pathways involved in immunity, such as NF-ΚB, MAPK, etc. However the mechanism of this process has not yet been elucidated. For conducting relevant experiments in vitro, a prokaryotic expression vector of CARD9-MBP fusion protein has to been construct, and the fusion protein need to be expressed and purified. Methods The coding sequence of CARD9 and MBP genes were amplified by PCR and the recombinant plasmid was correctly inserted into the pET-30a(+) vector. The recombinant plasmid was transformed into E.coli DH5α competent cells and proceeded PCR identification, restriction analysis and gene sequencing. The correct recombinant plasmid was transformed into E.coli BL21(DE3) competent cells. The target protein was induced to express by IPTG under different conditions. Relative molecular weight of the target protein was detected by SDS-PAGE electrophoresis. The CARD9-MBP fusion protein was purified by MBP maltose chromatography column and gel filtration chromatography column, and identificated by MALDI-TOF mass spectrometry after MBP-tag to be removed by HRV3C enzyme. Results The CARD9-MBP fusion protein was successfully constructed and confirmed by PCR and restriction analysis. The result of gene sequencing was consistent with the target sequence. The SDS-PAGE electrophoresis showed that the target protein with molecular mass (MR) about 105 000 was successfully induced to express in E.coli BL21 (DE3). A quite pure CARD9-MBP fusion protein was obtained by purification of MBP maltose chromatography column. Identification by MALDI-TOF mass spectrometry demonstrated that the target protein after MBP-tag to be removed by HRV3C enzyme is CARD9 protein. In the later stage, gel filtration chromatography column was used to obtain further pure CARD9-MBP fusion protein. Conclusion The prokaryotic expression vector of CARD9-MBP fusion protein was successfully constructed and a large number of soluble protein expressed. The purified target protein can be obtained by purification with MBP maltose chromatography column and gel filtration chromatography column.
ABSTRACT
Objective@#To express the NS6 nonstructural protein of human norovirus (NoV) in Escherichia coli, and to detect its enzymatic activity after purification.@*Methods@#Human NoV NS6 gene was cloned into the prokaryotic expression vector pDE1 and then was transformed into E. coli BL21 for expression. NS6 protein was purified by Ni-NTA affinity chromatography and Superdex 200 pg column. The activity of NS6 protein was determined by digestion of fusion protein 15VP1-6P at 37 ℃.@*Results@#Human NoV NS6 protein was stably and highly expressed in E. coli. After purification, the expressed product reached a purity of more than 95%, and the relative molecular weight of NS6 protein was about 23×103 Da. NS6 protein could cleave the fusion protein containing rhinovirus 3C cleavage site.@*Conclusions@#The nonstructural protein NS6 of human NoV was successfully expressed in Escherichia coli, which laid a foundation for further study on the pathogenesis of human NoV.
ABSTRACT
A 65-year-old male presented with recurrent palpitation and fatigue over one year. Lab tests revealed him with hyperinsulinaemic hypoglycemia. Insulin autoimmune antibody was repeatedly negative. Imaging of the pancreas seemed to be normal. Insulin-insulin autoimmune antibody complexes were detected by polyethylene glycol precipitation and gel filtration chromatography, thus the diagnosis of insulin autoimmune syndrome was suggested. By adjusting diet and administration of acarbose, all the symptoms were evidently relieved.
ABSTRACT
A 65-year-old male presented with recurrent palpitation and fatigue over one year. Lab tests revealed him with hyperinsulinaemic hypoglycemia. Insulin autoimmune antibody was repeatedly negative. Imaging of the pancreas seemed to be normal. Insulin-insulin autoimmune antibody complexes were detected by polyethylene glycol precipitation and gel filtration chromatography, thus the diagnosis of insulin autoimmune syndrome was suggested. By adjusting diet and administration of acarbose, all the symptoms were evidently relieved.
ABSTRACT
Objective To separate human γ-tubulin ring complexes (γTuRC) .Methods Cell lysates prepared from 293FT cells were separated using gel filtration chromatography .Then, the eluate fractions containing γTuRC or γ-tubulin small complexes (γTuSC ) were determined by immunoblotting .Results As the constitutive components of γTuRC,γ-tubulin,γ-tubulin complex protein 2 (GCP2), GCP3 and GCP4 were eluted and enriched in the fourth fraction .The molecular mass of eluates in the fourth fraction was about 2000 ×10 3 .Following γTuRC, the constitutive components ofγTuSC including γ-tubulin, GCP2 and GCP3 were eluted and enriched in the fourteenth fraction .The molecular mass of eluates in the fourteenth fraction was about 310 ×10 3 .Unassembled free components were washed out in the eighteenth and subsequent fractions .γTuRC could be detected in the corresponding fractions by negative-PAGE separation .ConclusionγTuRC and γTuSC were successfully separated from the unassembled free components in the fourth ( 4#) and fourteenth (14#) eluted fraction, respectively.The eluates containing ofγTuRC orγTuSC can be used for microtubule assembly research.
ABSTRACT
α-Glucan phosphorylase is an important enzyme of carbohydrate metabolism. In spinach leaves, it has been reported in two multiple forms viz. Pho 2 (cytosolic) and Pho 1 (plastidial). Here, we extracted and purified Pho 2 form of α-glucan phosphorylase from spinach using salting out with ammonium sulfate, desalting using Sephadex G-25 chromatography, anion exchange chromatography using DEAE-Sepharose and gel filtration chromatography using Sepharose-4-B. The purified enzyme had a specific activity, 150 units/mg protein. There was 38% recovery and 652 fold purification after final Sepharose-4B chromatography. The purified enzyme showed a single protein band on SDS sodium dodecyl sulfate polyacrylamide gel electrophoresis having molecular weight 94,000±2000 daltons. The native molecular weight is found to be 188,000±3000 daltons as determined using gel filtration chromatography over Sephadex G-200. The Pho2 exhibited optimum pH at pH 6.0 with two half pH optima at pH 5.2 and pH 7.0. The optimum temperature of Pho2 is found to be 37ºC with two half temperature optima at 30ºC and 40ºC. The Km value of the enzyme for starch and glucose-1-phosphate is found to be 116 μg/mL and 0.55 mM, respectively.
ABSTRACT
Aim To prepare soluble human C1 q and tumor necrosis factor related protein-6 in Escherichia coli and analyze the bioactivity. Methods Recombi-nant plasmid was transformed into E. coli expression strain, and the recombinant protein Trx-hCTRP6 was expressed induced by IPTG and then purified. Results Trx-hCTRP6 was expressed efficiently and purified using Ni-NTA affinity chromatography and Superdex G-75 column. The purified Trx-hCTRP6 was shown to be active under in vivo and in vitro assay conditions. Con-clusion Active Trx-hCTRP6 is efficiently prepared from E. coli protein expression system.
ABSTRACT
Aim To prepare soluble global human C1 q and tumor necrosis factor related protein-2 in Escherichia coli. Methods Recombinant expression plasmid was transformed into strain BL21-codonplus (DE3),and the recombinant protein of Trx-gH2 was expressed by IPTG induction and then purified by Ni-NTA affinity and gel filtration chromatography.Results The purified recombinant Trx-gH2 was shown to be active under in vi-vo and in vitro assay conditions.Conclusion Active recombi-nant global hCTRP2 is efficiently prepared from Escherichia coli protein expression system.
ABSTRACT
A two-step method for the purification of blocking-type anti-human CD80 monoclonal antibody 4E5 from mouse ascites was developed using anion exchange and gel filtration in combination. The ascites was first purified by anion exchange after centrifugation and filtration. The experimental parameters of sample loading and elution were optimized. The optimized loading condition was pH 8.0,50 mmol/L Tris-HCl and satisfactory results were obtained using a 0~0.5mol/L NaCl step elution. The fraction containing the protein of interest was directly loaded on gel filtration column and eluted using a 20 mmol/L phosphate buffer at pH 7.2. The purity of the obtained monoclonal antibody was up to 95% with a recovery of 61%. The purity of mAb could efficiently inhibit the growth of Daudi cells. The amplification of the method was also studied using a Bio-Scale Q5 column and the result was satisfied.