12 results about "Phagemid" patented technology

The present invention relates to a phage-based gene delivery system targeting human cells or animal cells, including immune cells, other human cells and cancer cells. In particular, the present invention relates to novel phage particles and associated phagemid expression systems and their production for the delivery of transgenes, comprising DNA encoding pathogen antigens, to human immune cells, suitable for use in vaccines and vaccine development against infectious diseases and cancers.

The invention discloses a fermentation medium for efficiently producing single-stranded DNA and a DNA nanostructure by a phagocytosis method and application of the fermentation medium, and relates to the technical field of biology. The fermentation culture medium is obtained by using ammonium chloride as a single inorganic nitrogen source to replace a nitrogen source (NH4) 2HPO4 in a Riesenberg culture medium. The invention also provides a method for efficiently producing single-stranded DNA (ssDNA) and a DNA nanostructure by a phagocytic grain method, high yield of the ssDNA can be promoted by adopting the fermentation culture medium, a nitrogen source is optimized and screened through the culture medium, and the invention finds that the yield of the single-stranded DNA can be increased by using ammonium chloride as a unique inorganic nitrogen source in the fermentation culture medium for production, and the yield of the single-stranded DNA can be increased by using the ammonium chloride as the unique inorganic nitrogen source in the fermentation culture medium. The yield of single-stranded DNA with triangular, hairpin rectangular, rod-like and quadrilateral DNA structures is increased to different extents by the fermentation culture medium, and a theoretical basis is provided for large-scale production of different types of ssDNA and DNA structures.

This invention discloses a shark-derived nanobody targeting the SARS-CoV-2 RBD protein and its applications. The nanobody's nucleotide sequence is shown in SEQ ID NO: 1, and its amino acid sequence is shown in SEQ ID NO: 5. Preparation involves immunizing a striped bamboo shark with the RBD protein, extracting total RNA from peripheral blood lymphocytes and reverse transcribing it into cDNA. The amplified VNAR fragment is then seamlessly ligated with amplified pR2 phage particles, transformed into TG1 competent cells, and a phage antibody library is constructed. SARS-CoV-2 RBD protein-specific nanobody sequences are screened from the library and recombinantly expressed to obtain the targeted shark-derived nanobody. The nanobody of this invention has a small molecular weight, allowing for the detection of the SARS-CoV-2 RBD antigen using paired nanobodies. It can be applied to immunoblotting, enzyme-linked immunosorbent assays (ELISA), and COVID-19 pharmaceutical applications related to the SARS-CoV-2 RBD protein.

The invention relates to the methods for modifying the methylation pattern of bacteriophage DNA and phagemid DNA and to methods for selective killing of bacteria using lysogenic bacteriophages comprising bacteriophage DNA or phagemid DNA comprising components of an engineered CRISPR-Cas system.

This invention provides a nanobody targeting carp herpesvirus type II and its application. The amino acid sequence of the nanobody is shown in SEQ ID NO. 1-6. The method includes immunizing alpacas with inactivated carp herpesvirus type II, collecting peripheral blood from the immunized alpacas and separating lymphocytes, and extracting total RNA; synthesizing cDNA by reverse transcription, and amplifying the gene fragment encoding the nanobody; ligating it into the pComb3xss vector, and then transforming it into competent cells to construct a nanobody phage display library; enriching and panning the inactivated virus as a coating antigen to obtain specifically binding phage particles; transforming the selected positive clones into host bacteria for induced expression; and obtaining the anti-carp herpesvirus type II nanobody after separation and purification. This invention aims to provide a carp herpesvirus type II nanobody that is low in expression cost and difficulty, has a stable source, can effectively bind to carp herpesvirus type II, and specifically achieves immunoassay of carp herpesvirus type II.

This invention describes a bacterial production strain containing a produced phagemide for the efficient production of high-quality circular single-stranded DNA (cssDNA). DNA molecules that can be used to efficiently produce high-quality cssDNA are also described herein. Therefore, a method for producing high-quality cssDNA is also described. The present invention provides, for example, a production strain comprising a phagemide and at least two phage protein coding sequences incorporated into the genome of the production strain, wherein the phagemide can produce cssDNA upon introduction.

The invention belongs to the technical field of polypeptide library construction, and particularly relates to a method for constructing a thiazole polypeptide library based on a phage display technology. The method comprises the following steps: firstly, introducing a thiazole group on a polypeptide chain by using thiazole synthetase, and determining the sequence preference of the enzyme through a model peptide so as to guide library design; and integrating a gene for coding the enzyme into a host bacterium genome by utilizing CRISPR-Cas9, and constructing a stably expressed chassis cell. Carrying out PCR (Polymerase Chain Reaction) amplification on a phage vector, carrying out NotI enzyme digestion and T4 connection to construct a DNA (Deoxyribose Nucleic Acid) library, and electrically transforming the DNA library to a chassis cell to obtain a phage library for displaying the thiazole modified polypeptide. The phage display of the skeleton modified polypeptide is realized for the first time, the structural diversity of the phage display polypeptide is obviously expanded by introducing the thiazole group with unique physicochemical properties, the polypeptide stability and membrane permeability are improved, and a new technical platform is provided for screening of high-affinity polypeptide and development of druggability lead compounds.

The application relates to a pyroglutamate A beta-targeted single-domain antibody and a preparation method and application thereof, the amino acid sequence of the single-domain antibody is shown in SEQ ID NO. 1 or SEQ ID NO. 2 or SEQ ID NO. 3 or SEQ ID NO. 4 or SEQ ID NO. 5 or SEQ ID NO. 6 or SEQ ID NO. 7 or SEQ ID NO. 8; a striped banded dogfish is taken as an immunization object, PE-A beta is taken as an antigen for immunization, total RNA of peripheral blood cells of the immunized dogfish is extracted, reverse transcription is carried out to obtain cDNA, amplification is carried out by taking the cDNA as a template, a phagemid carrier is constructed by taking the amplification as a template, the phagemid carrier is transferred into a competent cell, the competent cell is cultured, positive clones are screened, and the single-domain antibody is obtained. The single-domain antibody provided by the application can specifically recognize PEA beta, has good binding activity, has a small molecular weight, solves the technical problem that no shark nanobody targeting PEA beta has been found at present, lays an important foundation for subsequent research on the application of the antibody in the detection of PEA beta, and has application prospects in the development of a reagent for detecting PEA beta or a drug for treating PEA beta-related diseases.

Described herein are engineered bacterial producing strains comprising engineered bacteriophages for effective production of high quality circular single stranded DNA (cssDNA). In addition, DNA molecules that can be used to efficiently produce high quality cssDNA are described herein. Accordingly, a method of producing high quality cssDNA is also described.

The invention discloses a targeted monopterus albus rhabdovirus nano antibody as well as a preparation method and application thereof. The amino acid sequence of the nano antibody is SEQ ID NO.1-4; the method comprises the following steps: immunizing alpaca by adopting inactivated ricefield eel rhabdovirus, collecting mRNA after immunization, extracting, synthesizing and amplifying to obtain a DNA fragment for coding the nano antibody; connecting with a pComb3xss vector, and then transforming into a competent cell to construct and enlarge the culture to obtain a nano antibody library; the monopterus albus rhabdovirus is used as a coating antigen for enrichment panning screening to obtain monopterus albus rhabdovirus-resistant nano-antibody phagocytids, and finally the monopterus albus rhabdovirus-resistant nano-antibody phagocytids are converted into host expression bacteria for inducing expression of the nano-antibody and The nanometer antibody targeting the ricefield eel rhabdovirus is low in expression cost, low in difficulty and stable in source, can be produced on a large scale compared with a traditional monoclonal antibody, and has a wide application prospect in the field of ricefield eel rhabdovirus detection.