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.

The invention discloses a preparation method of oxalate decarboxylase. The method comprises the following steps: constructing a recombinant expression plasmid vector comprising Bacillus-containing acid induced promoter, a secretion signal peptide, and a fungus-derived oxalate decarboxylase gene prepared under the control of the secretion signal peptide, transforming bacilli normally growing in a pH value being not more than 4.5 by the vector to prepare oxalate decarboxylase recombinant bacteria; and carrying out culture and acid feeding on the recombinant bacteria in a fermentation medium, inducing the recombinant bacteria, and carrying out simple purification to recover generated extracellular oxalate decarboxylase. The extracellular oxalate decarboxylase prepared through the method is used in diagnosis reagent raw materials, medicinal compositions, healthcare foods or formulated foods with special medical uses. The mutated acid induced promoter is adopted to substitute an original acid induced promoter in the recombinant expression vector, so the transformed bacilli have a high expression level.

The invention discloses a grouper feed additive and a method for using the same. It is composed of photosynthetic bacteria liquid, Bacillus pumilus powder and Lactobacillus acidophilus liquid. First, the Bacillus pumilus powder is mixed with the Lactobacillus acidophilus liquid and then mix the obtained mixed bacteria with the photosynthetic bacteria liquid; the mass percent content ranges of the three components are: the photosynthetic bacteria liquid is 18% to 22%, the Bacillus pumilus powder is 1% to 3%, and the acidophilic The lactobacillus liquid is 75-81%; add 10g-50g of additives to 1kg of basic feed, mix well with the basic feed and wrap it with emulsified fish oil. The invention is applicable to the healthy cultivation of the grouper, can obviously improve the activity of SOD, AKP and lysozyme in the fish body, thereby effectively promoting the growth of the grouper.