69results about How to "High conversion frequency" patented technology

This invention relates to improved methods for the production of transgenic cotton plants, comprising cocultivating Agrobacterium cells comprising a DNA fragment of interest operably linked to at least one T-DNA border with cotton embryogenic callus in the presence of a plant phenolic compound.

Methods and compositions to increase Agrobacterium transformation efficiency (frequencies) in both dicot and monocot host plants include adding histones to the host plant at most transiently, and using histones and L-cysteine at certain stages in monocot transformation.

The invention discloses a hydrotalcite-loaded palladium catalyst for preparing styrene through selective hydrogenation of phenylacetylene and a preparation method thereof and application. According tothe catalyst, hydrotalcite is used as a carrier, and palladium is dispersed on the surface of the carrier in a nanoparticle form. The carrier is any one of ZnAl, NiAl, CoAl and NiFe hydrotalcite. Theactive component is palladium, and the mass fraction of palladium is 0.5-1.5%. The preparation method comprises the following steps of: dispersing hydrotalcite in mixed alcohol, adding a noble metalsalt solution, stirring for several hours, centrifuging and drying to obtain the hydrotalcite-loaded palladium nano-catalyst. The preparation method of the catalyst is simple and suitable for large-scale production. The obtained catalyst has extremely high activity and styrene selectivity in a selective hydrogenation reaction of phenylacetylene, and also has good stability and substrate universality.

The invention discloses a method for preparing polyether based on a three-component metal-free catalytic initiation system. The method comprises the steps of adding an epoxy monomer into a three-component metal-free catalytic initiation system containing hydroxy compounds, organic alkali and boron alkyl to react to obtain the polyether. The method is a currently known ethylene oxide room-temperature open-ring polymerization method with highest catalytic activity since the usage of organic alkali can be reduced to 40ppm and the conversion frequency can be 6000h/l. The polyether has the advantages of no metal residue and no cytotoxicity. The three-component catalytic initiation system adopts ethylene oxide open-ring polymerization, the chain transfer reaction toward the monomer and solvent can be completely avoided while the conversion frequency of 2720h/l can be obtained, and the polyether has the molecular weight of 0.1-400kg/mol, which can be accurately controlled. Furthermore, by utilizing the catalytic initiation system, the (poly) block polyether with controllable molecular weight, block sequence, block proportion and side base combination can be conveniently prepared by continuously adding materials.

Compositions and methods are provided for the production and selection of transgenic plants and plant parts, for increasing the transformation frequency of a plant or plant part, and for regulating the expression of a transgene, such as a herbicide tolerance polynucleotide. The methods and compositions allow for the delay in the expression of herbicide tolerance polynucleotides until a point in development during which herbicide selection is more efficient. Compositions comprise polynucleotide constructs comprising an excision cassette that separates a transgene, such as a herbicide tolerance polynucleotide, from its promoter and host cells comprising the same. The excision cassette comprises a polynucleotide encoding a site-specific recombinase operably linked to an inducible promoter and expression of the recombinase leads to excision of the excision cassette and expression of the transgene.

The invention provides improved plant transformation methods. In particular the method provides increased transformation frequency, especially in recalcitrant plants. The method includes various transformation protocols for monocots, such as maize and sorghum, using a combination of media and light conditions to achieve increased efficiency of monocot transformation and increased callus initiation frequencies.

The invention relates to the field of plant genetic engineering. Specifically, the invention relates to an efficient watermelon genetic transformation system and application. Growth regulation genes such as AtGRF5, TaGRF4, OsGIF1, ZmWUS and ZmBBM are included in watermelon genetic transformation. It is found for the first time that expression of AtGRF5, TaGRF4, OsGIF1, ZmWUS or ZmBBM genes in the watermelon transformation and/or regeneration process can promote the genetic transformation efficiency of watermelon crops, AtGRF5 can significantly improve the genetic transformation efficiency of watermelons by about 80 times, and precious gene resources are provided for genetic breeding. The invention further provides a method for using a fluorescent protein DsRed2 as a genetic transformation screening marker, and genetic transformation screening operation is simplified. When the system is expressed and used in watermelons, the genetic transformation breeding efficiency of the watermelons can be effectively improved, and the breeding cost is reduced.

The invention discloses a vacuum-infiltration assisted exogenous gene transforming method of a soybean germinating embryo, which comprises the following steps of: 1. carrying out disinfection and pre-culture processing on seeds; 2. after the expansion and the germination of seed embryos, cutting, exposing or damaging germinating embryo parts; 3. infecting the germinating embryos by agrobacteria containing target genes; 4. carrying out co-culture; 5. regenerating and screening clustered buds as well as rooting and screening plantlets; and 6. regenerating and screening the clustered buds as well as rooting and screening the plantlets. The method is applicable to multiple genotypes, has high regenerating speed and is a reliable system for soybean transgenic breeding.

The invention provides a method of effectively introducing exogenous genes into rice cells by utilizing PMI (phosphomannose isomerase) selective marker, a transformation system, as well as a preparation method of genetically modified rice by utilizing the method.

The invention provides a method for carrying out genetic transformation of agrobacterium-mediated Chinese white poplar. The method is characterized in that: an agrobacterium-mediated method is adopted to carry out genetic transformation of Chinese white poplar twice so as to introduce two exogenous genes, wherein the primary transformation adopts a plant binary expression vector containing neomycin phosphotransferase gene NptII and beta-glucuronic acid carbohydrase gene, and takes kalamycin as antibiotic; and the secondary transformation adopts a plant binary expression vector containing hygromycin phosphotransferase gene, and takes hygromycin as antibiotic. The method can effectively introduce the two exogenous genes into Chinese white poplar so as to improve plant characters better.

A process for quickly culturing transgenic plant of potato includes such steps as agroinfecting the potato explant cultured in test tube, culturing to introduce the target gene to potato receptor, direct culturing in solid differential culture medium to induce resistant buds, culturing in selective rooting culture medium to induco normal root, and verifying by PCR, PCR-southern, or Northern hybridizing method.

An object of the present invention is to provide a method of efficiently constructing a gene delivery carrier having a favorable activity and expression efficiency of a protein expressed by a gene introduced by transformation. Moreover, an object of the present invention is to provide a pharmaceutical composition comprising a gene delivery carrier constructed by the construction method and a therapeutic agent for solid tumor comprising the resistant bacterium. The objects of the present invention have been attained by a gene delivery carrier consisting of an anaerobic microorganism capable of growing in a tumor tissue in an anaerobic environment and capable of expressing (A) a protein having an antitumor activity or (B) a protein having an activity of converting an antitumor substance precursor to an antitumor substance, wherein DNA encoding the protein of interest is allowed to further comprise, on the 5′-terminal side thereof, a DNA fragment comprising a nucleotide sequence encoding a peptide consisting of an amino acid sequence from the 1st to at least 4th amino acids at the N-terminus of a histone-like DNA-binding protein.

The invention discloses a cucumber Flamingo-bill explant transgene method. In the method, the cucumber Flamingo-bill explant is used as an acceptor for gene transformation, the reported gene GUS gene is transferred in the acceptor by mediating agricultural bacillus, the transformed plant is preliminarily screened by kanamycin to obtain the resistance plant, and the resistance plant is subjected to PCR molecular identification and GUS dyeing to obtain the transgene plant. The method has the following advantages 1. at home and abroad, the Flamingo-bill explant is used as the acceptor to perform the genetic transformation of the cucumber for the first time; 2. the gene transformation frequency is as high as more than 30 percent; 3. the regeneration time of the transgene plant is short, and only 40 to 45 days are needed from selection culture to rooting; 4. the survival rate of the transgene plant is as high as 95 percent; and 5. the method is applied to the genetic transformation of multiple genotypes of the cucumber.

The present invention discloses a method for creating transgenic receptor system of corn and its application. The stem tip of corn is inoculated to the inducing culture medium added with combined hormones to induce the cultured stem tip to directly grow tussock uds or tissue block of tussock bud. Its next generation is cultured and its tussock buds or the tissue block of tussock bud are used as receptor. After the exogenous genes are transferred into cultured cells, such steps as recovery and screening are used to obtain transgenic plants. Its advantages are use of the most of gene-type cultured cells to regenerate transgenic plant, high frequency and less variation of characteristics.

The invention belongs to the technical field of plant cell engineering and molecular biology and relates to a method for establishing a ziziphus jujuba genetic transformation system for a receptor by leaves. The method includes: inoculating leaves of ziziphus jujuba into a WPM adventitious bud initial medium to perform dark culture induction for 2-4d to obtain explants; using agrobacterium liquor containing a plant expression vector to infect the explants to obtain infected explants; putting the infected explants on the WPM adventitious bud initial medium to perform dark culture for 2-4d; transferring the leaves subjected to dark culture into a WPM solid selection medium to perform dark culture for 14-16d, transferring to a position under light, performing elongation culture for leaf regeneration in a WPM medium containing 0.1mg/L of heteroauxin and 0.5mg/L of gibberellins to obtain adventitious buds, transferring the adventitious buds to an MS medium to perform propagation to obtain genetically transformed ziziphus jujuba plants. By the method, a proper regeneration system can be provided for ziziphus jujuba, high transformation frequency and high repeatability are realized, and genetic improvement of ziziphus jujuba is benefited.

A process for effectively introducing the exogenous genetic materials into living cell includes treating the living cell, tissue block, or organ of plant in hyperosmotic cultural liquid for a certaintime, putting it in the culture liquid containing exogenous genetic material, and stabbing by microbeam laser. The exogenous genetic material immediately comes in the cell via the stabbed hole which is then closed in 3 seconds. Its advantages are less damage to cell, the growth-promoting action of laser on cell, and correct location.

The invention provides a method for introducing a foreign gene into cleistogamy japonica rice by utilizing a PMI (phosphomannose isomerase) selection marker. Specifically, the method is characterized in that the foreign gene is introduced into the cleistogamy japonica rice variety 8m30 through mediation of an agrobacterium bacterial strain EHA 105 containing a pCAMBIA1381-PMI vector in the presence of mannose serving as a selection agent. PCR (polymerase chain reaction) detection and identification show that the foreign gene is introduced into the cleistogamy japonica rice variety 8m30. The method for introducing the foreign gene into the cleistogamy japonica rice by utilizing the PMI selection marker has the advantages that genetic transformation of the cleistogamy japonica rice variety is successfully realized, no antibiotics or herbicide is needed for selection, a character improvement process is sped up, gene drift caused by outward propagation of pollen is avoided, and further environment friendliness is improved.

The invention provides a muskmelon genetic transformation method based on glufosinate-ammonium as a selection marker. The method comprises the following steps of: 1) constructing a recombinant expression vector with a BlpR gene, and transferring into agrobacterium to obtain a recombinant strain; 2) infecting the melons cotyledon paraxial end segment by adopting the recombinant agrobacterium in a sterile environment, and placing the infected cotyledon segment on a co-culture medium to grow, so as to obtain an expanded cotyledon explant; 3) transferring the expanded explants to a differential screening culture medium for culture, and inducing cluster buds; 4) separating the elongated cluster buds into single plants, transferring, and further screening and culturing to obtain seedlings with melon overground parts; (5) transferring the seedlings with the melon overground parts into a rooting culture medium, and inducing root differentiation to obtain T0-generation muskmelon transgenic seedlings; and 6) doubly identifying the T0-generation muskmelon transgenic seedlings through glufosinate-ammonium test paper and PCR (Polymerase Chain Reaction) to obtain strains completing genetic transformation. By the method, stably-transformed muskmelon seedlings can be obtained.