4results about How to "Lower immune response" patented technology

The invention provides a PEG / CaCl2 mediated Penicillium citrinum genetic transformation method, and belongs to the technical field of microbial genetic transformation, and the method comprises the following steps: adding a target gene segment into Penicillium citrinum protoplast suspension, and carrying out an ice bath reaction; the target gene segment is obtained by taking pJET-hph-02944 plasmid as a template and carrying out PCR (Polymerase Chain Reaction) amplification by adopting a hygromycin B resistance gene primer pair with gene sequences as shown in SEQ ID No. 1 and SEQ ID No. 2; adding a PTC (Positive Temperature Coefficient) buffer solution into the mixed system, uniformly mixing and standing; continuously adding a TB3 liquid culture medium containing ampicillin, and carrying out recovery culture; uniformly mixing the resuscitated protoplast with a molten TB3 solid culture medium, pouring a plate, and carrying out dark culture for the first time; then covering a TB3 solid culture medium containing hygromycin B and ampicillin, carrying out secondary dark culture to obtain a transformant, and transferring the transformant to a PDA plate containing hygromycin B for screening. According to the method, CaCl2-PEG is adopted for mediated transformation of Penicillium citrinum, the transformation efficiency is higher, and the transformation speed is higher.

The invention discloses a gamma-PGA synthetase gene cluster pgsBCA '. The gamma-PGA synthetase gene cluster pgsBCA' is formed by sequentially connecting genes pgsB, pgsC and pgsA 'in series, the genes pgsB and pgsC are derived from a gamma-PGA synthetase gene cluster BA-pgsBCA of the bacillus altitudinis; the gene pgsA'is derived from a gamma-PGA synthetase gene cluster BM-pgsB 'C' A 'of bacillus megatherium. Bacillus amyloliquefaciens CF of which a genome knockout polyglutamate synthetase gene cluster is used as a host, and a recombinant polyglutamate synthetase gene cluster pgsBCA'is subjected to free expression through plasmids, so that a gene engineering strain capable of synthesizing gamma-L-PGA is obtained. When the strain is used for producing gamma-L-PGA in a 5L fermentation tank through amplification fermentation, the maximum yield can reach 10.5 g / L. Besides, the gamma-poly-L-glutamic acid is free of cytotoxicity and low in immunogenicity, so that the gamma-poly-L-glutamic acid has a wide application prospect in the fields of preparation of wound dressings, in-vivo absorption materials and the like. The invention provides a new material basis and technical support for application and development of polyglutamic acid in the fields of medicine and related biomedicine.

This invention belongs to the field of genetic engineering technology, specifically relating to a modular tandem repeat recombinant type III collagen with high platelet adhesion and its applications. The amino acid sequence of the recombinant type III collagen includes repeating units, with ≥3 repeating units; functional modules are inserted within each repeating unit. This invention integrates multiple discrete platelet-binding sites in type III collagen, designs a tandem repeat structure of different modular sequences (≥3 repeating units), optimizes spatial synergy, optimizes the gene sequence using codon bias, efficiently expresses the gene through a Pichia pastoris expression system, and obtains a high-purity product after purification. The recombinant type III collagen prepared by this invention exhibits good biocompatibility and can significantly promote erythrocyte and platelet adhesion; it can be widely used in wound repair, hemostatic materials, and tissue engineering.

The invention provides a multifunctional composite neural electrode system and a preparation method, and belongs to the technical field of implanted electrodes, specifically, the multifunctional composite neural electrode system comprises an electrode main body, a circuit adapter plate, a fixed frame, a catheter structure and a replaceable inner core, the electrode main body comprises an insulating substrate, a metal wiring layer and an insulating layer which are stacked in sequence, the electrode main body is provided with an electrical detection site and a leading-out bonding pad, a metal wiring layer at the electrical detection site and the leading-out bonding pad is exposed, the replaceable inner core comprises an implantation guide needle, an optical fiber and an injection inner tube, and the replaceable inner core is inserted from one end, far away from the tip of the electrode main body, of the sleeve, enters the implantation tube through the insertion core and extends out of the far end of the implantation tube. By designing a universal catheter structure and a replaceable inner core, the neural electrode realizes multi-mode nerve detection or stimulation, multiple functions are selected according to actual requirements, and integration of all functional parts is avoided, so that the overall structural size is reduced, and the damage to the brain in a long-term experiment can be reduced.