308 results about "Genetic stability" patented technology

The invention relates to the technical field of stem cell biology, and discloses a stem cell quality evaluation system and method, and the system comprises a data collection module which collects local environment data and image data of stem cells in a preset range; the morphological recognition module is used for obtaining cellular morphological data of all stem cells in a preset range through a cellular morphological recognition model; the graph structure data construction module is used for constructing graph structure data; the score marking module is used for measuring the multiplication capacity, the genetic stability capacity and the surface marker expression capacity of the stem cells after the preset duration, and obtaining the quality score of the stem cells through manual marking; the model training module is used for training a stem cell quality scoring model through an optimization algorithm; according to the method, the cellular morphology data of the stem cells are extracted through the multi-branch network of the cellular morphology recognition model, and the interaction among the stem cells is comprehensively considered through the stem cell quality scoring model, so that the accuracy of stem cell quality evaluation is improved.

The invention provides a uracil production strain and a construction method and application thereof.According to the strain, on an E.coli UR14 genome by means of a CRIPSR / Cas9 gene editing technology, firstly, psuG genes, preTA genes, rutA genes and upp genes are knocked out, so that decomposition of uracil is blocked; then, a uridine phosphorylase gene udp and a pyrimidine-5 '-nucleotide nucleotidase gene ppnN are subjected to overexpression, and synthesis and accumulation of uracil are synergistically enhanced; and finally, overexpression of the ribose phosphate mutase gene pgm further enhances the conversion of a by-product ribose phosphate 1-precursor 5-ribose phosphate 1-pyrophosphate and improves the carbon utilization rate, and the obtained strain has good genetic stability and high fermentation yield, can stably produce uracil, and has wide application prospects.

The invention belongs to the technical field of food microorganisms, and particularly discloses a ganoderma lucidum mutant strain capable of producing polysaccharides and triterpenoids at high yield. The strain is named as Ganoderma lucidum in Latin, the preservation number is CGMCC NO: 41680, the preservation unit is China General Microbiological Culture Collection Center, and the preservation date is December 4, 2024. The strain is named as Ganoderma lucidum, the preservation number is CGMCC NO: 41680, and the preservation number is CGMCC NO: 41680. The polysaccharide content in the ganoderma lucidum spore powder produced by the ganoderma lucidum mutant strain is more than or equal to 8%, and the total triterpenoid content is more than or equal to 12%; a culture medium formula of the ganoderma lucidum mutant strain comprises potato leachate, glucose and monopotassium phosphate, the culture temperature is 25-28 DEG C, and the pH value is 5.5-6.5. The ganoderma lucidum mutant strain is high in genetic stability, the content of active ingredients is remarkably higher than that of parent strains, and the ganoderma lucidum mutant strain is suitable for large-scale fermentation production.

The invention provides a nicotinamide nucleotide transhydrogenase mutant and application thereof, valine at the 169th site of the nicotinamide nucleotide transhydrogenase mutant is designed to be mutated into isoleucine, the isoleucine is used for constructing a lysine production strain, and the new strain does not contain plasmids, does not have growth defects, does not need induction, and has the advantages of good genetic stability, high fermentation yield and the like. The lysine can be efficiently and stably produced from the beginning by taking glucose as a substrate.

A Schizochytrium algae strain rich in n-3 fatty acid and a screening and culture method therefor. Compared with a conventional strain, the content of EPA and the content of n-3 DPA in the provided strain are greatly improved, and the strain has good genetic stability, fast growth rate and good industrialization prospects. Also provided are a culture medium for mutagenesis of Schizochytrium sp., a culture medium for screening Schizochytrium sp., and a suitable mutagenesis method and screening method.

The invention provides a valine production strain and a construction method and application thereof, a designed acetohydroxy acid synthase mutant is that the 88th basic group of an ilvB gene is changed from a to c, the 382nd basic group is changed from a to g, the 413th basic group is changed from c to t, the gene sequence of a designed artificial operon comprises a promoter, an ilvB (A138V) gene or ilvB (Q30K, S128G, A138V) gene of coding mutated acetohydroxy acid synthase, and an ilvN (G20D, I21D, I21D, I21D, I21D, I21D, I21D, I21D) gene. I22F) gene, a pyk gene for coding pyruvate kinase, and a terminator; by designing a specific acetohydroxyacid synthase mutant and related biological materials and artificial operon, the strain constructed by directional modification of the strain by using a pK18mobsacB system gene editing technology based on allele exchange has the advantages of good genetic stability, high fermentation yield and the like, and valine can be stably produced.

The invention discloses a method for improving biocontrol photosynthetic bacteria through a far-source hybridization and genome rearrangement technology. The method comprises the following steps: inoculating a rhodopseudomonas palustris GJ-22 seed into a photosynthetic bacteria liquid culture medium for culturing; inoculating the bacillus subtilis KY-2 into an LB liquid culture medium for culturing; the cultured GJ-22 is taken and subjected to treatment and centrifugation, and then a GJ-22 protoplast is obtained; kY-2 is taken to be treated, and KY-2 protoplast is obtained after centrifugation; fusing the obtained GJ-22 protoplast and KY-2 protoplast, diluting a photosynthetic bacterium hypertonic liquid culture medium, and regenerating on a photosynthetic bacterium soft agar culture medium to obtain a fused strain; a fusion strain is screened out through an induced tobacco core leaf anti-TMV test to serve as a starting strain for genome rearrangement. Preparing protoplast from the original strain; dividing the prepared protoplast into two groups, and respectively carrying out ultraviolet inactivation and thermal inactivation; respectively fusing the inactivated protoplasts, and regenerating to obtain fusant strains; finally, a target strain with genetic stability is screened through a fusant strain induced tobacco core leaf anti-TMV test.

The invention belongs to the technical field of synthetic biology, and particularly relates to recombinant escherichia coli for efficiently producing O-acetyl-L-homoserine as well as a construction method and application of the recombinant escherichia coli. According to the invention, CRISPR-Cas9 gene editing is combined with metabolic modification, so as to precisely integrate OAH biosynthesis key nodes: introducing and overexpressing a mutant metX gene at a genome pseudogene site to enhance the expression of homoserine acetyltransferase, knocking out byproducts such as poxB and mgsA to synthesize genes, and carrying out high-yield synthesis of OAH. Corynebacterium glutamicum thrA (anti-feedback inhibition), aspB and bacillus subtilis acsA-acuA genes (construction of an acetic acid switch) are introduced, gene expression of gltA, tpiA and the like is optimized to increase supply of precursors such as acetyl CoA and the like, and finally a stable strain without plasmids, antibiotics and inducers is obtained. The production cost is effectively reduced, and the method has the advantage of high genetic stability and shows a good application prospect in OAH industrial production.

The invention belongs to the technical field of genetic engineering, and discloses a schizochytrium limacinum genetic engineering strain for enhancing supply of acetyl coenzyme A and efficiently producing astaxanthin, a method and application of the schizochytrium limacinum genetic engineering strain. By heterologous expression of a beta-carotene ketolase CrtO gene and a beta-carotene hydroxylase CrtZ gene from haematococcus pluvialis, synthesis of astaxanthin from beta-carotene in schizochytrium limacinum is promoted, so that the content of astaxanthin in schizochytrium limacinum HX-308 is increased. According to the invention, the endogenous AACT gene and heterologous CrtO, CrtZ, PK and PTA genes of schizochytrium limacinum are integrated into an original strain through homologous recombination, and the obtained strain still keeps genetic stability after multiple subculture, has the capability of efficiently synthesizing astaxanthin, effectively improves the yield of astaxanthin, and lays a foundation for large-scale industrial production.

The invention relates to the technical field of biology, in particular to an SNP (Single Nucleotide Polymorphism) marker combination for identifying tilapia streptococcus agalactiae disease resistance and application thereof. The invention discloses 11 SNP loci significantly related to streptococcus agalactiae resistance in a tilapia UTRN gene, and constructs 18 SNP marker combinations for streptococcus agalactiae resistance phenotype identification, so that the resistance phenotype identification accuracy and hereditary stability can be effectively improved. Besides, according to the SNP typing primer and method based on the # imgabs0 # MALDI-TOF mass spectrum platform, high-throughput and high-precision genetic typing can be achieved, and the SNP typing primer and method have important application value in resistance phenotype identification and assistant selective breeding.

The invention discloses recombinant yarrowia lipolytica with high yield of 3-fucosyllactose as well as a construction method and application of the recombinant yarrowia lipolytica. According to the invention, a reinforced lactose transporter lac12 gene, a reinforced GDP-mannose-4, 6-dehydratase gmd gene, a reinforced GDP-L-fucose synthase gmer gene and a 3-fucosyltransferase SUMO-fut3Bc gene with a reinforced SUMO tag are subjected to integrated expression on a recombinant yarrowia lipolytica chromosome, and a 6-phosphogluconolactonase pgl gene is subjected to overexpression, so that a recombinant yarrowia lipolytica strain is obtained. The constructed recombinant yarrowia lipolytica can maintain the genetic stability of a target gene, the yield and production efficiency of 3-fucosyllactose are remarkably improved, and the requirements of industrial production can be met.

The present invention discloses an enterovirus infectious clone with a novel HiBiT reporter gene and a construction method and application thereof, including enterovirus EVA71, CVA16, CVA10 and CVA7 infectious clones with a novel HiBiT reporter gene, using HiBiT as a reporter gene for the first time on the basis of EVA71, CVA16, CVA7 and CVA10 infectious clones, preparing EVA71-HiBiT, CVA16-HiBiT, CVA7-HiBiT and CVA10-HiBiT infectious clones, further rescuing the reporter virus by the infectious clone, and verifying the biological activity and genetic stability of the reporter virus by cytopathic effect, plaque, WB and flow cytometry in vitro. The virus clone or reporter virus involved in the present invention has a wide range of application value in the field of anti-enterovirus drugs and high-throughput screening of neutralizing antibodies.

The invention belongs to the technical field of biology and new medicine, and discloses a method for constructing a myxobacteria expression chassis with genetic stability and application of the myxobacteria expression chassis. Through gene deletion and overexpression analysis, it is verified that the spontaneous mutation rate of a strain can be reduced by deletion of a TLS pathway and overexpression of RecA, and a myxobacteria strain 2K7 with genetic stability is further constructed on the basis. The spontaneous mutation rate of the new strain is reduced by 11.5 times, and the transformation capability of growth plasmids of the strain is obviously improved. According to the research, the genetic stability of the myxobacteria is improved for the first time through a repair way after modification and replication, and the research method and the research result are innovative.

The invention relates to the technical field of molecular biology or agriculture, in particular to an SNP (Single Nucleotide Polymorphism) molecular marker related to a southern rust gene RPPK and application. The SNP loci, the primers and the detection method capable of resisting southern rust gene RPPK typing are successfully developed, the southern rust gene RPPK can be accurately subjected to genetic typing, and the SNP molecular marker has the characteristics of high throughput, low average cost, high genetic stability, accurate and reliable genetic typing data, easiness in automatic detection and the like; and the method has an extremely high value in commercial breeding.

The invention provides a valine production strain as well as a construction method and application thereof, the strain is constructed by utilizing a CRIPSR / Cas9 system gene editing technology based on allele exchange, an artificial operon is designed and constructed, the artificial operon is constructed at a ygaY site, a strong promoter Ptrc is used for controlling ilvIH (G14N S17F)-pykF to carry out synchronous multi-copy expression, and the valine production strain can be used for producing valine. On the basis of the strain, an artificial operon is constructed at an ycgH site, a strong promoter Ptrc is used for controlling ilvC-ilvD to carry out synchronous multi-copy expression, meanwhile, feedback inhibition of valine on ilvIH is relieved, and an ilvIH natural promoter is replaced by the strong promoter Ptrc, so that more pyruvic acid flows to valine; the constructed strain does not contain plasmids, has no defects, does not need induction, has the advantages of good genetic stability, high fermentation yield and the like, and can be used for efficiently synthesizing valine from the beginning by taking glucose as a substrate.

The invention discloses an ILTV gD protein antigen epitope expression cassette, a recombinant virus and application, and relates to the field of gene and protein engineering. The ILTV gD protein antigen epitope expression cassette provided by the invention comprises T and B cell epitopes of gD protein derived from an infectious laryngotracheitis virus WG strain. The recombinant virus rH120-gD-T / B is obtained by replacing a 5ab gene of an infectious bronchitis virus H120 strain with a gene for coding an ILTV gD protein antigen epitope expression cassette. The recombinant virus has good genetic stability, can be used for developing a safe and effective IB-ILT bivalent live vector vaccine, and solves the problem of poor stability of the current recombinant IBV.

The application relates to the technical field of gene chips, in particular to a SNP molecular marker combination of Pinus massoniana and application thereof. The SNP molecular marker combination is composed of 113,709 SNP molecular markers, wherein the physical position of the SNP molecular markers is determined by sequence alignment based on a reference genome Pinus.tabuliformis V1.0 of Pinus tabulaeformis. The application provides a whole genome chip of Pinus massoniana containing 113,709 SNP sites for the first time, and the chip has the advantages of high efficiency, low cost, good genetic stability and the like, and can be widely applied to different application scenarios such as identification of Pinus massoniana germplasm resources, genetic background analysis of breeding materials, gene positioning, whole genome association analysis, whole genome selection breeding and intelligent design breeding.

The invention relates to recombinant bacillus subtilis for displaying PRRSV ER protein on spore surfaces, a construction method and application. The recombinant bacillus subtilis is obtained by constructing a recombinant vector which takes spore capsid protein CotB as anchoring protein and displays PRRSV ER protein on the surface by using a genetic engineering method on the basis of an integrated plasmid pDG364, and transforming the recombinant vector into wild bacillus subtilis 168 by using a chemical transformation method, and has genetic stability; and loss in the passage process is avoided. According to the strain, antigen protein is directly displayed on the surfaces of spores, crushing is not needed, animals can be immunized through direct material mixing or water drinking, and the tedious process of large-scale injection is avoided. And due to the good stress resistance of the spores, the strain is easy to store and transport, and the cost is remarkably reduced. The strain can induce specific immune response, provides a new way for prevention and treatment of PRRSV, and is suitable for development of commercial vaccines.

The invention provides a truncated insulator and an expression system comprising the insulator and applied to eukaryotic cells, the truncated insulator breaks the setting of an original core area, shortens the effective sequence of the insulator, and is more beneficial to the integration of the insulator and other elements of a carrier. The insulator can obviously improve the yield of protein in an expression system with transposon (such as PiggyBac) and obtain a recombinant cell strain with good hereditary stability.

The invention relates to the technical field of environmental microorganisms and resource fermentation, and discloses a Kluyveromyces marxianus BMK7 for protein production and biogas slurry purification and application of the Kluyveromyces marxianus BMK7, the BMK7 is Kluyveromyces marxianus and is obtained through ultraviolet mutagenesis and hygromycin B adaptive evolution, the preservation number is CCTCC NO: M 20251050, and the Kluyveromyces marxianus BMK7 has good growth performance and genetic stability. The strain can be efficiently fermented under the condition that biogas slurry serves as a main substrate, ammonia nitrogen and chemical oxygen demand (COD) in the biogas slurry are remarkably reduced, and meanwhile high-proportion mycoprotein is synthesized. The thalli have strong flocculability and good sedimentation characteristics, and are beneficial to protein recovery. The method can be widely applied to treatment and resource utilization of sewage such as breeding wastewater, kitchen fermentation liquor and anaerobic effluent, and has a good industrialization prospect.

The invention discloses a preparation method and application of a 5k liquid phase chip for cattle variety and paternity test. Based on original genome data of cattle varieties in the target cattle variety set and the amplified cattle variety set, position information of genome SNP sites of all the varieties is obtained, and then sites with variety specificity or high genetic stability are screened through Delta and FST value methods; and classifying varieties by combining a machine learning classification model to obtain a specific site combination meeting requirements as a target SNP site combination. The obtained SNP site combination can achieve 100% identification accuracy when variety identification is carried out on a target variety, and efficient, low-cost, large-scale and automatic variety and paternity identification is realized; the production type of the detected cattle can be effectively judged, a pasture can be better assisted to select the cattle for both dairy and meat, the overall milk yield and the milk quality are increased, and the income is increased.

The invention belongs to the field of microbial breeding and fermentation engineering, and particularly relates to a saccharomyces cerevisiae mutagenesis strain with high yield of S-adenosyl-L-methionine as well as a mutagenesis method and application of the saccharomyces cerevisiae mutagenesis strain. Saccharomyces cerevisiae is induced to generate genetic diversity through multiple rounds of ultraviolet mutagenesis, and high-throughput screening is performed in combination with strain color phenotypic difference; and the mutant strain HY2402-Z18 with high yield of S-adenosine-L-methionine and genetic stability is obtained. The SAM yield of the mutagenic strain is increased by 40.1% compared with that of an original strain, the SAM yield reaches 13.44 g / L when the mutagenic strain is fermented for 60 h in a 5 L fermentation tank system, the unit yield reaches 0.156 g / L / OD, and the methionine conversion rate is 75%. After thalli are collected through centrifugation of fermentation liquor, an S-adenosine-L-methionine product with the purity of 98%-100% can be obtained through purification of ion exchange resin, no by-products are accumulated, the yield, the substrate conversion rate and the production efficiency of the S-adenosine-L-methionine can be remarkably improved when the mutagenesis strain is used for fermentation production, and the production cost is reduced. The production cost is effectively reduced, the product purity and quality are improved, and the method is suitable for industrial large-scale production of SAM.

The invention discloses a marker screening and model building method for precise evaluation of parent genome breeding values, and belongs to the technical field of molecular breeding and genomics. The method comprises the following steps: acquiring genetic typing data and target character phenotype data of a reference group, and performing digital coding; calculating a secondary allele frequency (MAF) and a linkage imbalance score (LD score) of each marker site; based on the joint screening rule of the MAF and the LD score, screening to obtain a core marker subset with relatively high genetic stability and linkage structure representativeness; and constructing a differentially weighted genome prediction model based on the core marker subset to estimate the genome breeding value of the parent individual. According to the method, allele frequency information and linkage imbalance structure information are jointly utilized, interference of low-frequency or weak linkage sites on the prediction model is reduced, the prediction accuracy of parent breeding values in cross-generation predictor representative types is improved, and the method is suitable for genome prediction and molecular breeding of complex characters.

The invention provides an L-lysine production strain as well as a strain construction method and application. A hom (V59A) is introduced on a genome by utilizing a homologous recombination gene editing technology to weaken a competitive approach of lysine; the lysC (T311I) which is not inhibited by L-lysine is overexpressed; the method comprises the following steps of: overexpressing lysE, lysA, ddh, dapB and asd, knocking out a lysI gene and multi-copying the lysE, carrying out synchronous multi-copying on the dapA and EcdapB genes through a manual operon P1676-EcdapB-Pa12-dapA, and carrying out synchronous multi-copying on the dapB, ddh, lysA and lysO genes through a manual operon Psod-dapB-ddh-Ptuf-lysO-lysA; the constructed strain does not contain plasmids, has no defects, does not need induction, has the advantages of good genetic stability, high fermentation yield and the like, and can be used for stably producing L-lysine.

This invention discloses a method for directed evolution of antibiotic-resistant Escherichia coli strains based on cytidine deaminase, belonging to the field of microbial directed evolution and genetic engineering technology. This method uses E. coli as the host, introducing a recombinant plasmid expressing an optimized double-stranded cytidine deaminase mutant. Utilizing the low toxicity and high mutagenicity of this mutant, continuous passage evolution is carried out under gradient concentrations of aminoglycoside antibiotics (kanamycin and streptomycin). Combined with whole-genome sequencing, molecular docking, and reverse genetics verification, the A145T missense mutation in the wcaE gene is identified as the core functional site. This invention overcomes the shortcomings of traditional spontaneous and chemical mutagenesis, which suffer from low efficiency and significant strain damage. The mutation type is controllable, the evolutionary cycle is short, and the obtained engineered strains can tolerate up to 300 mg / L kanamycin while exhibiting streptomycin cross-resistance, and the genetic stability of the tolerance trait is strong. This method is simple, highly reproducible, and suitable for industrial breeding of stress-resistant E. coli, and can be widely applied in antibiotic fermentation, industrial microbial culture, and other scenarios.

The invention belongs to the technical field of fish genetic breeding, and relates to a method for screening hemorrhagic disease resistant grass carp and application of the method in hemorrhagic disease resistant breeding of grass carp. Based on a genomics rapid breeding technology, a batch of grass carps capable of resisting the hemorrhagic disease are accurately screened out through the steps of constructing a grass carp experimental group, identifying phenotypes through artificial infection of grass carp hemorrhagic disease viruses, analyzing and identifying genotypes through high-throughput sequencing, carrying out associated screening on SNP sites related to the hemorrhagic disease and the like. The method realizes efficient breeding in a breeding cycle of the grass carp, has the advantages of high efficiency, low cost, genetic stability and the like, can effectively solve the breeding loss caused by hemorrhagic disease of the grass carp, and assists high-quality and green development of aquaculture industry in China.

The invention provides a method for improving the genetic stability of PolyA tail of mRNA (messenger ribonucleic acid). The method for improving the genetic stability of the PolyA tail in the preparation process of the mRNA containing the PolyA tail comprises the steps that a plasmid vector containing three-segment PolyA polynucleotides A1-G-A2-G-A3 is transferred into a host cell to be cultured, A1, A2 and A3 are each independently composed of 30-45 continuous A, and the host cell is selected from DH5a, Stbl3 and JM109; and separating and recovering a plasmid vector containing PolyA polynucleotide, carrying out enzyme digestion linearization to obtain an mRNA transcription template, and carrying out transcription to prepare mRNA. According to the method, the high genetic stability of the plasmid PolyA tail sequence can be achieved, the stability of mRNA is not affected, the mRNA protein translation efficiency is not affected, and the Oligo-dT purification process is not affected.

The invention relates to the technical field of rotaviruses, in particular to a G8P [8] type group A rotavirus CZ-23 and application thereof. The invention relates to a G8P [8] type group A rotavirus CZ-23, which is preserved in China General Microbiological Culture Collection Center (CGMCC) on April 11, 2023, and the preservation address is No.3, Yard 1, Beichen West Road, Chaoyang District, Beijing; the preservation number is CGMCC (China General Microbiological Culture Collection Center) The invention provides a novel human rotavirus wild strain which is reported and separated for the first time in China, and the strain is strong in virus replication capability and good in hereditary stability, can be applied to development of vaccine strains of human rotavirus vaccines, and is suitable for attenuated rotavirus oral vaccines.

The invention discloses streptococcus equi subsp. Zooepidemicus, application of the streptococcus equi subsp. Zooepidemicus and a method for producing hyaluronic acid, and belongs to the technical field of microorganisms. The streptococcus equi subsp. Zooepidemicus disclosed by the invention is streptococcus equi subsp. Zooepidemicus SYMY-010, the strain is preserved in the general microbiological center of the China Committee for Culture Collection of Microorganisms on December 26, 2022, and the preservation number is CGMCC (China General Microbiological Culture Collection Center) NO.26282. The streptococcus equi subsp. Zooepidemicus SYMY-010 disclosed by the invention can be used for preparing the streptococcus equi subsp. Zooepidemicus SYMY-010. The streptococcus equi subsp. Zooepidemicus SYMY-010 is inoculated into a fermentation culture medium for fermentation to produce the hyaluronic acid, the yield of the hyaluronic acid is up to about 15g / L, the average molecular weight of the obtained hyaluronic acid is 0.47 * 10 < 6 > Da, and meanwhile, the hyaluronic acid has good hereditary stability and better acid resistance.

The invention discloses a recombinant genetically engineered bacterium for producing a micafungin precursor FR901379 and an application of the recombinant genetically engineered bacterium. The recombinant genetically engineered bacterium for producing the micafungin precursor FR901379 is obtained by performing overexpression on an epigenetic modification factor in a phomopsis sheathing genome and performing screening to obtain the recombinant genetically engineered bacterium for producing the micafungin precursor FR901379. The epigenetic modification factor comprises a histone methyltransferase (Dot 1), a histone methyltransferase (Set2) or a histone deacetylase (Rpd3). The yield of FR901379 produced by the engineering strain is increased by 40% compared with that of an original strain. The method disclosed by the invention has the characteristics of simplicity and convenience in operation, high transformation efficiency and good genetic stability.