54results about How to "Increase mutation frequency" patented technology

A method for DNA reassembly after random fragmentation, and its application to mutagenesis of nucleic acid sequences by in vitro or in vivo recombination is described. In particular, a method for the production of nucleic acid fragments or polynucleotides encoding mutant proteins is described. The present invention also relates to a method of repeated cycles of mutagenesis, shuffling and selection which allow for the directed molecular evolution in vitro or in vivo of proteins.

A minicell display method has been developed which has significant advantages for screening peptide libraries for candidates that can bind and effectively modulate a particular biological process. The method, based on the small, anucleate minicell, has increased versatility in generating unique sequences to screen as well as increasing the size of the peptides to be screened. In vivo mutagenesis, at the level of protein synthesis, as well as DNA replication, increases diversification of the library to be screened and therefore substantially increases the number of potential peptides that can modulate a particular biological response or mechanism.

The invention provides a polymorphic hansenula polymorpha mutant strain and application of the polymorphic hansenula polymorpha mutant strain in glutathione biosynthesis. Firstly, low-energy ions N+ serve as a mutagenesis source, mutagenesis treatment for Hansenula polymorpha DL-1 is achieved, a glutathione (GSH) high-producing strain (DL-18) is obtained, the temperature remains 37 DEG C, the speed remains 180 r/min, shake flask fermentation remains for 42 hours, the dry cell weight (DCW) in end products is 7.04 g/L, the total quantity of the GSH is 420.46 mg/L, and the DCW in the end products and the total quantity of the GSH are respectively improved by 1.73 times and 1.94 times compared with the original mutant strain. Hereditary stability of the DL-18 is detected through subculture, yatsushiro is cultivated, content changes of the GSH are not significant, and therefore, the hereditary stability of the mutant strain is high.

The present invention relates to the identification and isolation of a DNA polymerase and uses of this polymerase. In particular, the present invention describes the nucleotide sequence of the human gene for DNA polymerase lambda (Pol λ), the amino acid sequence of Pol λ, and the amino acid sequence of several isoforms derived from alternative splicing of its mRNA. The association of some of these isoforms with tumour samples makes Pol λ a marker for the diagnosis, prognosis and evolution of tumoral processes.

A process for modifying cotton variety by space induction includes such steps as hybridizing between the cotton as female parent with high specific strength and the early-mature, high-yield and a disease-resistant cotton as male parent, space induction treatment of hybridized seeds, then reproduction further, backcrossing for breeding, and choosing by multiple generations. Its advnatages are high mutation frequency, several variant types, broad various spectrum, high yield and high resistance to diseases.

The invention discloses a method for producing high-activity beta-galactosidase bacillus circulans strain and a breeding method of the strain. The produced high-activity beta-galactosidase bacillus circulans strain is bacillus circulans QHT-310-M481 is preserved in the China center for type culture collection on October 22nd, 2018. The preservation number is CCTCC NO:M 2018699, and the preservation address is Wuhan university, Wuhan, China. The produced high-activity beta-galactosidase bacillus circulans strain is obtained from a bacillus circulans original strain through mutagenizing by meansof 1-methyl-3-nitro-1-nitrosoguanidine, and a beta-galactosidase solution high in fermentation activity can be produced and used for an industrial catalytic galactosyl transfer reaction to produce galactooligosaccharide.

The invention relates to a DNA multiple directed mutation method in the gene engineering technique field. The invention acquires directed multiple high-frequency DNA discontinuity by applying unidirectional PCR reaction, augmenting the discontinuity sequence specifically, increasing the discontinuity formwork quantity and associating the superimposed extension PCR, which changes the designing method of the primer in favor of the formwork compound and the superimposed extension among the fragment, and improves the burst frequency. The invention provides a simple and effective method for mutagenizing DNA directionally in the external.

The invention relates to a 60Co-gamma ray radiation mutation breeding method for iris sanguinea tissue culture seedlings. The method comprises the following steps of 1, tissue culture seedling selection; 2, 60Co-gamma ray radiation treatment; 3, tissue culture seedling mutant primary selection; 4, enrichment subculture of primarily selected mutants; 5, rooting culture of primarily selected mutanttissue culture seedlings; 6, domestication transplanting; 7, field seedling mutant screening; 8, cutting propagation, tissue culture propagation and artificial selection. According to the method, theiris sanguinea tissue culture seedlings are adopted as materials, 60Co-gamma rays are utilized for mutation treatment, the mutagenic effect of different radiation dosages on the iris sanguinea tissueculture seedlings is observed, the proper radiation dosage is determined, and the iris sanguinea tissue culture seedling 60Co-gamma ray radiation mutation breeding technology is set up; by means of the method, rich heritable variations can be created, the breeding period of iris sanguinea is effectively shortened, a simple, convenient and efficient method is provided for new variety breeding, andthe hereditary basis of iris sanguine genetic resources is widened.

The invention relates to the technical field of mutation breeding of lactic acid bacteria, and provides a method for breeding weak post-acidification streptococcus thermophilus strains. The method comprises the following steps: S1, preparation of a bacterial suspension: culturing an original strain to obtain a bacterial solution, transferring and continuously culturing the bacterial solution to a logarithmic metaphase, centrifuging, washing and concentrating the bacterial solution to obtain the suspension, and placing the suspension in an empty plate for later use; S2, ultraviolet irradiation: placing the suspension under an ultraviolet lamp for irradiation; S3, rejuvenation culture: resuspending the bacteria obtained in S2 in a fresh culture medium for rejuvenation culture; S4, penicillin treatment: adding penicillin for treatment, performing dilution, and coating an MC culture medium with the solution for culture; and S5, screening weak post-acidification strains. According to the technical scheme, the problem that the weak post-acidification streptococcus thermophilus strain cannot be efficiently bred in the prior art is solved.

Described herein is a novel, mitochondrial encoded, open reading frame, that leads to the production of a new mitochondrial peptide. Residing within the ND-Two subunit, a specific small nucleotide polymorphism disrupts expression of this mitochondrial peptide, and is correlated with an increase in obesity and diabetes, particularly in certain ethnic populations. In vitro administration of the peptide increases insulin secretion, decreases fat accumulation and improves glucose uptake in muscle cell. Antibodies generated against the peptide can be used for detecting peptide deficiency, in addition to SNP detection, supporting diagnostic approaches. In vivo studies further revealed that administration of the peptide improves glucose tolerance, thereby providing a new therapeutic avenue for a novel diabetes therapy and decreases bodyweight, thus serving as a novel obesity therapy. Generation of synthetic analogs further enhance or abrogated activity relative to the natural peptide.

The invention relates to a method for changing patterns and colors of maidenhair. The breeding method of a new species of the maidenhair mainly contains natural variation, hybrid breeding, space breeding and induced mutation breeding by ion radiation, but the frequency of the natural variation is low, the hybrid breeding process is complicated, and the space breeding cost is high. Dry seeds of the maidenhair are vertically plugged onto flower mud of a culture dish, a germ faces upwards, and the germ part is exposed; the well-prepared sample is placed into an ion radiation vacuum system to face the radiation source; the vacuum system is vacuumized to 10 to 4Pa; the ion radiation source is started, and the ion radiation technical parameters are adjusted; and the ion radiation is carried out, the ion radiation source is closed after the ion radiation is completed, the vacuum system is inflated, and the maidenhair dry seeds are taken out to be bred. The method is low in cost, wide in variation frequency spectrum, high in variation rate, convenient to operate and wide in application prospect.

The invention discloses a method for widening tetraploid wheat genetic variation. The method comprises the following steps that parent tetraploid wheat AABB is utilized to hybridize with diploid aegilops tauschii DD, in-vitro culture is carried out on a hybrid young embryo ABD to obtain an ABD plant seedling, then chromosome doubling treatment is carried out to obtain low-generation artificially synthesized hexaploid wheat AABBDD, the low-generation artificially synthesized hexaploid wheat AABBDD is backcrossed with the same parent tetraploid wheat AABB to obtain a pentaploid wheat material AABBD, the pentaploid wheat material is used for selfing, chromosome behaviors such as chromosome exchange, translocation, inversion, deletion and insertion are generated through chromosome recombination in the selfing process, rich variation types are generated in genetic offspring, and a new tetraploid wheat material composed of different chromosomes is formed. According to the method, the chromosome of the tetraploid wheat can be induced to generate new structural variation in a relatively short time, and the method is high in beneficial mutation efficiency, rich in mutation type, environment-friendly, safe and low in cost.

The invention belongs to a breeding technique of agriculture and forestry industrial crops, and particularly relates to an induced-mutation breeding method for obtaining new mutant germplasm based on 60Co-gamma-ray irradiation for whole grafted seedlings of mangifera indica. The breeding method comprises the breeding steps of (1) collecting seeds of mellow mangifera indica, accelerating germination until plant height is 9-11cm, performing transplanting to a nutrition bag, and performing breeding as rootstock seedlings; (2) collecting branches of the mangifera indica of the selected variety and 0.5-1 aged old, and grafting the branched to the rootstock seedlings so as to obtain grafting seedlings; (3) performing grafting for about 1-3 weeks, and treating the grafted seedlings through 60Co-gamma-ray irradiation; and (4) screening out the grafted seedlings with obvious trait changes namely the new germplasm of the mangifera indica, performing field planting in land for growing field crops and preforming further breeding utilization. According to the breeding method disclosed by the invention, a great quantity of new good-quality germplasms of the mangifera indica, having individual gene variation and property mutation can be quickly and effectively created, besides, original heredity background and good properties are maintained, and the breeding method has positive significance in avoiding the present situation that excellent germplasm resources of the mangifera indica are in short, and improving the good variety breeding efficiency of the mangifera indica.

The invention discloses a multifunctional plasma mutation apparatus, and the mutation apparatus comprises a plasma generating system for generating plasma which mutates mutating objects; an ultraviolet mutation device for executing ultraviolet mutation to the mutating objects; a chemical mutation device for performing chemical mutation to the mutating objects; a multifunctional loading platform where appliances used for mutation experiment are placed; an automatic control system for automatically controlling the plasma generating system, the ultraviolet mutation device, the chemical mutation device and the multifunctional loading platform so as to realize multiple mutating modes. Through the multifunctional plasma mutation apparatus, single-factor mutation and compound mutation can be executed and there are wonderful mutating types, thus the microorganism is greatly improved in mutation frequency and mutation types.

The invention discloses a method for regulating saccharomyces cerevisiae oxygen stress through Y-family polymerase Rev1, and belongs to the technical field of bioengineering. A gene REV1 is knocked out through a homologous recombination method, a knock-out strain rev1 delta is constructed, thus the oxidation stress resisting ability of a yeast strain is lowered, specifically, under the stress condition, the biomass of the knout-out strain is decreased by 9%, the survival rate is decreased by 34.8%, the gene mutation frequency is decreased by 63.8%, and the yield of pyruvic acid is decreased by30.8%. The gene REV1 is over-expressed through pY26 plasmid, an overexpression strain rev1 delta/REV1 is constructed, thus the oxidation stress resisting ability of the strain is enhanced, specifically, the biomass is increased by 8.3%, the survival rate is increased by 11.5%, the gene mutation frequency is increased by 186.2%, and the yield of the pyruvic acid is increased by 57.7%. The resultsshow that Rev1 can improve the survival ability and fermentation performance of the yeast strain under the oxygen stress condition.

The invention provides a chemical mutagenesis method for increasing the mutation range of dwarf bananas through induction. The chemical mutagenesis method comprises the following steps of preparationof a proliferation culture medium, mutagenesis treatment of the bananas, washing treatment and proliferation culture. According to the chemical mutagenesis method, a lithium chloride solution is adopted to treat and inhibit the growth of seedlings, so that the growth vigor is obviously different, and single plants with special characters appear in form; through mutagenic agent treatment, the mutation frequency is increased, the variation range is expanded, and the mutation frequency can be increased to 8.89% at most and is 1000 times or above higher than the natural mutation frequency throughchemical mutagenic agent treatment; and the mutation types are intensively represented as leaf color mutation, leaf type mutation and plant type mutation, wherein 6.47% of plants are represented to have bright green leaves, 7.11% of the plants are represented to have yellow stripes, 1.96% of the plants are represented to have leaf edge curling, and 4.50% of the plants are represented to have shortleaves, so that the artificial mutation range is wide, and the mutation types are rich.

The invention relates to a method for the heavy ion irradiation mutagenesis of streptomyces avermitilis strains and the culture of irradiation strains, belonging to the field of microbe strain breeding. The fermentation titer of the streptomyces avermitilis strains achieves 4000 microgrammes/milliliter by the traditional mutagenesis method and is very difficult to enhance again. The method comprises the following steps of: carrying out mutagenesis by adopting 12C+6 heavy ion beam irradiation, wherein an irradiation dose is 40-70 Gy, and a preferred irradiation dose is 50 Gy; and screening direct mutation strains of a plating medium and a slant medium to obtain high-titer strains reaching the fermentation titer of 6000 microgrammes/milliliter. The invention has stable and fast mutation, easy mutation control and simple, convenient and easy operation of the method.