Expression and Identification Truncated Glycoprotein G of Bovine Respiratory Syncytial Virus in Escherichia coli / 中国生物工程杂志

Two fragments G1 and G2 of the glycoprotein G gene of bovine respiratory syncytial virus(BRSV) were selected for expression in Escherichia coli based on the analysis of glycoprotein G by DNA Star software.Then the two fragments of glycoprotein G were amplified by PCR with synthesized G gene of BRSV as the template.The amplified fragments G1 and G2 are 570bp and 308bp in length,respectively.The PCR products were cloned into pET30a vector and expressed in soluble form in E.coli after induction of cultured E.coli with IPTG.Both of the recombinant proteins G1 and G2 were purified by immobilized Ni ion affinity chromatography under native conditions.Then the purified proteins were analysed by Western blotting.The results showed that the purified recombinant protein G1 retained good antigenicity and specificity.But the purified recombinant protein G2 didn't possess biological activity.Antibodies against BRSV were detected in suspected bovine serum samples in China by using indirect ELISA and Western blotting with the purified recombinant protein G1.The purified recombinant protein G1 might be used as antigen for establishing serological methods for diagnosis of BRSV infection.And the purified recombinant protein G1 might also be used for preparing polyclonal and monoclonal antibodies for research on biological functions of glycoprotein G of BRSV.

Cloning, Expression and Purification of Gene Encoding Human ?-NGF in E.coli / 中国生物工程杂志

Nerve growth factor is one of the most important factors playing an important role in regulating the growth, development and survival of the neuron. The purified NGF from human placenta has been reported, the tissue from which can be isolated the NGF is very limited. It is important for basic research and clinic application to expression hNGF by genetic engineering. By polymerase chain reaction,gene fragment encoding the mature part of ?-NGF was amplified using the DNA of human placenta as template. The fragment was sequenced and inserted into expression vector pET-15b, and the recombinant expression vector pET15b-NGF was transformed into E.coli BL21(DE3)pLysS. After inducing with IPTG the NGF was higher expressed up to 25% of the total cell proteins. The expression product was purified with metal chelate affinity chromatography on Ni-IDA agarose under denaturing condition. The purity of rNGF was higher than 90% and yield of rNGF was 4.56mg/L expressing bacteria. SDS-PAGE revealed the NGF expression product had a Mr 16kDa. Western-blot displayed the recombinant product had strong immunological activity with rabbit anti-human ?-NGF polyclonic antibodies. The expression products were dealed with solubilizing inclusion bodies and refolding protein. The test of nerve fiber growth of chicken embryo DRG neurons displayed rNGF had biological activity.

Cloning, Sequencing and Expression of Trichinella spiralis p49 Gene / 中国寄生虫学与寄生虫病杂志

Objective To conduct cloning, sequencing and expression of Trichinella spiralis ES antigen p49 gene. Methods RT-PCR was used to amplify the specific gene fragment from the total RNA of Trichinella spirais larvae. The PCR product was ligated to the T-vector and the recombinant plasmid was verified by sequencing. T-p49 and pGE-4T-3 were treated by both BamHI and XhoI. The ligation reaction was catalyzed by T4 DNA ligase. Results The p49 gene was cloned by using RT-PCR. Sequence analysis showed that the p49 gene obtained was consistent to the p49 sequence reported in the database. The expressed protein was shown as a new band at SDS-PAGE. BLAST analysis demonstrated that this p49 gene was 99% identical to the p49 gene reported and to the 43 kDa secreted glycoprotein gene in the database. Conclusion p49 gene from Trichinella spiralis larvae was cloned, sequenced and expressed.

Construction of an Eukaryotic Expression Vector pcDNA3-Glutathione-S-Transferase A1 Gene From Human Liver cDNA Library and Partial Sequence Determination / 环境与健康杂志

Objective To construct an eukaryotic expression vector carrying human glutathione-S-transferase(GST)A1gene and to provide study materials for toxicology and pharmacogenetic.Methods The GST A1cDNA was amplified and separated from human liver total RNAs by RT-PCR approach and recombined with eukaryotic expression vector pcDNA3.The recombined plasmid pcDNA3-hGSTA1was verified using PCR,restriction analysis and sequencing determination.Results Human GST A1gene was recombined correctly with pcDNA3,compared with Genbank,in code152T→C,amino acid Met→Thr.Conclusion The eukaryotic expression vector pcDNA3-hGSTA1was constructed for research on toxicology and pharmacogenetics.

Cloning, Sequence Analysis and Expression of Glutamate Dehydrogenase in Brevibacterium flavum GDK-9 / 微生物学通报

The glutamate dehydrogenase (EC.1.4.1.4) gene which amplified from the genome of Brevibacterium flavum GDK-9 by polymerase chain reaction was linked with pUCm-T for sequence alignment. Analysis of gdh sequences revealed that the whole sequence is 1927 bp, only one ORF existed, which used ATG as the initiation codon and coded a peptide of 448 amino acids with a calculated molecular weight of 48 kD. The comparability between the cloned gdh sequence to the reported sequence is high to 99.55%. Only the 1190th base mutation (C→A) lead to the change of amino acid sequence (Thr→Asn), the others are not. The recombinant plasmid pXG was then transformed into E. coli XL-Blue and Brevibacterium flavum GDK-9 which was induced by IPTG. SDS-PAGE analysis revealed that there was a clear induced protein band with molecular mass of 48.7 kD on expected position. Standard glutamate fermentations indicated that although the level of GDH increases the intracellular glutamate pool, the level of GDH has no influence on glutamate secretion.

CLONING OF NATTOKINASE GENE AND EXPRESSION IN E. COLI / 微生物学通报

In this study, nattokinase gene was amplified by PCR using bacillus subtilis chromosomal DNA as template and cloned into expressed vector pBV220. After transforming recombinant plasmid into E.coli HB101, the recombinant strain was yielded. It was proved that expression products was secretive and expression protein was 12% of total cell protein by SDS-PAGE. Optimum culture time and inducing time was determined as 6h and 5h respectively. The plasmid stability studies showed that recombinant plasmid has excellent segregational stability but the structural stability was not good in the host cell.