868 results about "Genetic stability" patented technology

The teachings herein are generally directed to a method of enhancing the genetic stability of parvovirus vectors. The stability of conventional ss or dsAAV vector constructs can be enhanced, for example, to obtain a concurrent increase in vector titer and purity, as well as an improvement in vector safety, due at least in part to the elimination of stuffer DNA from the AAV vector. The method is broadly applicable to all gene transfer / therapy applications, such as those requiring delivery of foreign DNA containing recombinant gene expression cassettes. Such foreign DNA can range, for example, from about 0.2 up to about 5.2 kb in length. The enhanced vector constructs are highly flexible, user-friendly, and can be easily modified (via routine DNA cloning) and utilized (via standard AAV vector technology) by anyone skilled in the art.

The invention provides a method using a CRISPR-Cas system to perform GING2 gene editing on an epidermal stem cell and particularly relates to a method for building an epidermal stem cell line with theGING2 gene being knocked out. Two specific gRNAs are built and acquired, and the GINS2 gene editing efficiency of CRISPR / Cas9 in the epidermal stem cell can be increased evidently. An epidermal stemcell GINS2 knockout plasmid is good in hereditary stability and high in targeting efficiency.

The invention discloses a tea source eurotium cristatum strain which is named as eurotium cristatum XU08 and is preserved in the CGMCC (China General Microbiological Culture Collection Center) on March 13, 2012 with a preservation number of CGMCC No.5891. Researches on the morphological feature, the physiological property, the genetic stability and the growing conditions of the strain during the production of the Fuzhuan tea and industrial trial production of the strain prove that the strain is available as a special leavening agent for the production of the Fuzhuan tea, so that the production cycle can be shortened and the product quality can be improved, and therefore, the strain is very suitable for modern production needs of the Fuzhuan tea.

A vaccine comprising an immunologically effective amount of recombinant modified vaccinia Ankara (rMVA) virus which is genetically stable after serial passage and produced by a) constructing a transfer plasmid vector comprising a modified H5 (mH5) promoter operably linked to a DNA sequence encoding a heterologous foreign protein antigen, wherein the expression of said DNA sequence is under the control of the mH5 promoter; b) generating rMVA virus by transfecting one or more plasmid vectors obtained from step a) into wild type MVA virus; c) identifying rMVA virus expressing one or more heterologous foreign protein antigens using one or more selection methods for serial passage; d) conducting serial passage; e) expanding an rMVA virus strain identified by step d); and f) purifying the rMVA viruses from step e) to form the vaccine. One embodiment is directed to a fusion cytomegalovirus (CMV) protein antigen comprising a nucleotide sequence encoding two or more antigenic portions of Immediate-Early Gene-1 or Immediate-Early Gene-2 (IEfusion), wherein the antigenic portions elicit an immune response when expressed by a vaccine.

The invention relates to a method for conserving chrysanthemum in vitro through reducing major element in the medium, which is special for the in vitro conservation of the chrysanthemum germplasm resource. The invention comprises the steps of: taking the suckers of the chrysanthemum as the explants, and axillary buds for subculture, and conserving on the 1 / 2MS, 1 / 2MS (1 / 2NH4+) or 1 / 4MS medium containing 6-BA0.3mg / L and NAA0.1mg / L. The survival rate for a 12-month conservation is 100%, 8 months longer than that of conservation on the normal MS medium. After the conservation material recovers to normal growth, the descendant is proved to have no genetic variance through the detection of POD, EST and ISSR. The invention uses the method of conserving chrysanthemum test-tube plantlet through reducing major element in the medium and identifies the genetic stability of the descendant, which proves that the plants grow normally after one-year conservation and the descendant has no genetic variation.

The invention provides a mthod for propagating dendrobium candidum test-tube plantlets, which comprises the following steps: a. adopting dendrobium candidum stem sections or stem section axillary buds as explants, wherein chloroplasts of the stem sections or the stem section axillary buds have gene sequences with the GenBank login number of FJ530946; and b. carrying out the processes of axillary bud survival and growth, cespitose shoot inducement and multiplication, and plantlet formation, wherein the culture conditions include the culture room temperature of 26+ / -2 DEG C, the illumination intensity of 20001x, the pH value between 5.8 and 6.0, the light source of a fluorescent lamp or an LED light source, and the illumination time of 12 h per day. The method of the invention aims at the defects of the existing dendrobe tissue culture method, improves the existing dendrobe tissue culture method, and provides a fast propagation method of the dendrobium candidum germchits. The method can meet the requirements of germchits required by large-scale production in a short time, and has the characteristics of low cost, regular germchit growth, simplicity and easy implementation of a domestication method, good inheritance stability and the like.

The invention discloses an avermectin B1a high-yielding strain, which is classified and named streptomyces avermitilis AVE 07-N2-16515, and is preserved in a China type culture preservation centre (CCTCC) with the preservation number of CCTCC NO: M2012094. The avermectin B1a high-yielding strain disclosed by the invention is obtained by combining low-energy nitrogen ion implantation-lithium chloride (N<+>-LiCl) compound mutation with ultraviolet ray-lithium chloride (UV-LiCl) compound mutation, primarily screening, and performing shake-flask fermentation secondary screening, and is used as a starting strain for next mutation, so that the target strain AVE07-N2-16515 is finally screened. The obtained strain can greatly increase the avermectin B1a component and reduce other components in fermentation products, and is good in hereditary stability. The strain is fermented in a 5L fermentation tank to produce avermectin B1a by utilizing glucose as a quick-acting carbon source and cornstarch as a delayed-action carbon source, the titer can achieve 3048 mu g / m, which is improved by 23.4% as compared with the original starting strain AVE07; and the strain can be applied on industrial production, greatly improves a fermenting unit, and has great economic application value.

The invention provides a quick propagation seedling-breeding method for reducing vitrifaction in multiple times of subculture of a rosaceous plant. The method comprises disinfection of explants, induction of buds, sub propagation and rooting induction. The method is characterized in that: in the sub propagation process, test tube seedlings are subjected to rejuvenation culture alternately, and then vigorous test tube seedlings with height of 1 to 3 centimeters are selected and transferred into a rooting culture medium for induced rooting so as to obtain complete test tube plants, wherein a starting culture medium without containing any exogenous plant hormone for rejuvenation is adopted in the rejuvenation culture. The method is quick, efficient, low in cost and convenient for popularization, has good genetic stability and low vitrifaction ratio in the culture process, keeps the propagation coefficient in a high level, and is suitable for tissue culture and quick propagation of the rosaceous plant.

The invention discloses an induction and in-vitro culture method of plant stem cells derived from apical meristem of catharanthus roseus roots. The induction method comprises the following steps: cutting off a root cap from the root tip of the catharanthus roseus, performing inoculating to an induction culture medium, performing culturing in dark, and proliferating and growing a stem cell layer inan explant to form a cell cluster; transferring the layered stem cell layer to a subculture medium for culturing for 10-15 days, and performing complete culturing in dark; and performing transferringto a new subculture medium, and performing culturing for 10-15 days under the same condition to obtain a catharanthus roseus stem cell line with stable cell morphology. A catharanthus roseus stem cell culture system is established by inducing apical meristem of the catharanthus roseus roots, stable subculture can be performed under certain conditions, and epigenetic variation is avoided. The catharanthus roseus stem cell culture system established by the invention has the characteristics of being high in growth speed, high in genetic stability and the like, and culture with a 10L bioreactor is preliminarily realized.

The invention relates to an enterovirus type 71 (abbreviated as EV71) and use thereof, in particular to a monoclonal virus strain which is separated by a plaque assay method. The progeny viruses of the monoclonal virus strain show genetic stability. The monoclonal virus strain can be used in the production of a vaccine (particularly the production of a vaccine for infant). The virus strain or the vaccine produced by using the same can be used in the prevention of diseases (such as hand-foot-and-mouth diseases, particularly hand-foot-and-mouth diseases in children) caused by the EV71 and has the characteristics of stable titer, high immunogenicity and small immunizing dose.

The invention discloses a method for cultivating a subcultured bud of an upright crown tissue culture seedling of fir wood. The method comprises the following steps: an excellent clonal annual burgeon of the fir wood is used as an explant, a breeding bud is obtained through disinfection, sterilization and tissue culture, the breeding bud is innoculated in a proliferation culture medium comprising 1 / 2MS, 1.0mg / L of 6-BA and 0.5mg / L of IBA for inducing the cluster buds to sprout, the subcultured bud which is germinated at the base of the breeding bud and is healthy in growth is selected and is cut in a common rooting culture medium, seedlings are exercised and transplanted, and when the height of the seedlings of the fir wood is 15-30 cm, the seedlings are taken out of a garden for forestation. When the method is used, the proliferation rate of the subcultured bud of the fir wood is as high as 4-6, the breeding speed is high, the seedling culturing number is large, the tissue culture subcultured bud with high genetic stability, 100% of the upright crown rate of the tissue culture seedling and more than 96% of the rooting rate can be in batch production in a short period, and the requirements of the construction and the development of a fir wood reserving base of China for good seedlings can be met, so that the method has better economic benefits, social benefits and ecological benefits.

The invention provides a hansenula polymorpha expression system, a hansenula polymorpha construction method and application of hansenula polymorpha. The expression system contains uracil auxotroph hansenula polymorpha AU-0501, of which the preservation number is CGMCC NO.7013. The uracil auxotroph hansenula polymorpha AU-0501 provided by the invention has the advantages of definite mutation site, low reverse mutation frequency, good hereditary stability, high biological expression quantity and the like, plays a significant role in researching and producing gene engineering vaccine, has the advantages of higher yield and low cost as compared with other eukaryotic expression systems adopted at present. The invention further provides an expression vector applied to the hansenula polymorpha expression system and a construction method of the expression vector. Two or more genes can be expressed simultaneously through the expression vector. Two target genes can be expressed in a hansenula polymorpha auxotroph cell at a high level without interference.