61results about How to "Strong secretory ability" patented technology

The invention discloses a method for inducing human umbilical cord mesenchymal stem cells into testicular interstitial cells and application thereof. The method comprises the following steps: cloning mouse steroidogenic factor-1 (SF-1) gene into an adenovirus shuttle plasmid pAdtrack-CMV-EGFP to construct a recombinant vector pAdtrack-CMV-SF-1; recombining the recombinant vector pAdtrack-CMV-SF-1 and an adenovirus carrier plasmid pAdEasy-1 to obtain an adenovirus plasmid pAd-SF-1 carrying SF-1 gene; digesting and linearizing the adenovirus plasmid pAd-SF-1, and packaging with human embryonic kidney cells AD-293 to obtain adenovirus; adding the adenovirus into an induction culture medium to infect human umbilical cord mesenchymal stem cells, and carrying induced differentiation of the human umbilical cord mesenchymal stem cells to testicular interstitial cells. Through the induction using the method of the invention, human umbilical cord mesenchymal stem cells can in vitro differentiate into testicular interstitial cells only in one week, so as to provide an important cell source for treatment of testosterone deficiency using cell replacement or genetic method.

The invention discloses a preparation method and application of recombinant duck interleukin 2 protein. Duck interleukin-2 cDNA fragments amplified by RT-PCR, prokaryotic expression vector pBAD / his B vector and eukaryotic expression vector pMETαA were used to construct high-efficiency expression plasmids, and the recombinant expression vectors were transformed into Escherichia coli LMG194 and yeast strains PMAD11 and PMAD16 respectively induced expression. After induction of Escherichia coli, the crude product of duck interleukin-2 can be obtained by ultrasonic cracking and centrifugation to remove precipitation, and the pure product of duck interleukin-2 can be obtained by protein purification system. The crude or pure duck interleukin-2 can be used as immune adjuvant, disease resistance additive and disease treatment drug after adding protective agent. The preparation process of duck interleukin-2 monoclonal antibody and polyclonal antibody is simple and economical, and can be used as a good immunosuppressant. The recombinant duck interleukin-2 protein prepared by applying the genetic engineering technology in the invention has the characteristics of simple technological process, low production cost, good stability, high biological activity and the like.

The invention discloses a glutamine transaminase mutant with improved enzymatic activity, which belongs to the field of enzyme engineering. The site-specific mutagenesis is performed on glutamine transaminase, an amino acid residue close to an active site of the glutamine transaminase is changed, so that the catalytic efficiency of the glutamine transaminase is improved, and the enzymatic activityof the glutamine transaminase is further improved. Recombinant yarrowia lipolytica with improved enzymatic activity is established by the glutamine transaminase mutant, the enzymatic activity of theglutamine transaminase is improved by 1.45 times compared with an original strain, the enzymatic activity of the shake flask fermentation can reach 16.995U / mL, and the enzymatic activity of the fermenting tank fermentation can reach 59.85U / mL which is the highest fermentation value reported at present.