1. Development of genetically modified technology Since humans learned to store animals and cultivate plants, our ancestors have never stopped genetic improvement of species. The main ways to improve species over the past few thousand years: breeding and utilizing the genes and recombinant individuals produced by mutations or unintentional human factors caused by the natural environment to optimize genes through random and natural accumulation. However, this passive mode with very low probability and no human control greatly hinders the development of agriculture and urgently needs an emerging science. Since the establishment of genetics, this situation has been changed. Animal and plant breeding has been carried out by artificial hybridization to carry out the recombination of excellent genes and the introduction of foreign genes to achieve genetic improvement. Figure 1: Schematic diagram of changes in plasma membrane before (left) and after (right) electroporation Figure 2: Principle and application of electroporation 2. Transgenic Animals In 1981, the first successful introduction of foreign genes into animal embryos led to the creation of transgenic animal technology. In 1982, transgenic mice were transferred to rat growth hormone gene, which made mice weigh twice as much as normal individuals, and thus called "super mice", which opened up transgenic cloned animals - asexual reproduction technology. In 1997, I. Wilmut et al. of the United Kingdom transplanted the nucleus of sheep mammary gland cells into the nucleus of the nucleus, and successfully obtained the cloned sheep "Dolly", which confirmed that higher mammals can also break through the reproductive reproductive offspring. Dongsheng Innovation Company Li Qianqian Ginger Powder,Dehydrated Ginger Powder,Air Dried Ginger Powder,Dried Ginger Powder Xinghua Dongbao Foods Co.,Ltd , https://www.xhdongbaofoods.com
Therefore, both transgenic technology and traditional technology are genetically improved by obtaining excellent genes. However, in the scope and efficiency of gene transfer, transgenic technology is different from traditional breeding techniques in two ways: First, traditional techniques can only achieve gene transfer among individuals within a species, while genes transferred by transgenic technology are not affected by organisms. Second, traditional hybridization and selection techniques are generally carried out at the level of biological individuals. The target is the entire genome, and a large number of genes are transferred. It is impossible to accurately locate a gene for manipulation. And selection, the phenotypic predictability of future generations is poor. The transgenic technology operates and transfers a well-defined gene with clear functions and accurate prediction of future generations. Therefore, transgenic technology is the development and supplement of traditional technology, and the combination of the two can greatly improve the efficiency of animal and plant variety improvement.
In the process of GM development, from the early research and development of research to the current research and application, the intersection of biology and other fields has important functions, such as microscopy technology produced by biophysics, and electroporation technology. Greatly promoted the application of scientific research.
Electroporation technology is the most widely used in the field of transgenics. As early as 1982, Neumann.E introduced foreign DNA into mouse eukaryotic cells under electric field conditions [1], thus realizing genetic recombination and function of foreign genes. the study. This technology has been widely used, such as in vitro applications of bacteria, yeast, plant and animal cells such as Simon, J. R [2]; and organ implantation, electrochemical treatment of skin damage repair, vaccine injection, etc. In vitro and in vivo clinical applications, such as S. Tollefsen, et al [3]; functional studies of small molecules or macromolecules; development of transgenic animals, new varieties of transgenic plants, etc., the application of transgenic plants and animals will be specifically described below.
Electroporation mainly includes electrotransfection and electrofusion: electrotransfection uses pulsed electric field to introduce foreign DNA into cells. When the cells are in a high voltage electric field, transient electrical pulses can perforate the cell membrane to produce a reversible pore size, thereby allowing DNA to enter the cell. Integration with chromosomes; electrofusion is the use of high-intensity electric field pulses that cause adjacent cell fusion.
The simple principle and application of electroporation technology is shown below. 
Nuclear microinjection is the most common method used in early animal transgenic technology. It is to inject a foreign gene into the pronucleus of a fertilized egg cell under a microscope, and the injected foreign gene is fused with the embryonic genome, then cultured in vitro, and finally transplanted into the uterus of the recipient dam, so that each animal in the animal is born. Cells contain new DNA fragments. However, the shortcomings of this method are low efficiency, positional effect (random gene insertion site randomness), uncertainty of expression results, low animal utilization rate, etc., and there are still long reproductive cycles in ruminants. Strong time constraints, the need for a large number of donors and recipient animals.
Somatic cell nuclear transfer is a new transgenic technology that has emerged in recent years. The method firstly cultures the foreign gene and the donor cell in the culture medium, integrates the foreign gene into the donor cell, and then transplants the donor cell nucleus to the recipient cell, the enucleated oocyte, to form a reconstruction. The embryo is then transplanted to the pseudopregnant mother, and after the pregnancy and childbirth, the transgenic cloned animal can be obtained. In this technique, stable expression of foreign genes and good development of reconstructed embryos are key factors, and it is particularly important to select appropriate gene transfection methods and cell fusion methods.
Electroporation has many advantages over conventional methods. First, you don't have to use glass needles like microinjection, you don't need technical training and expensive equipment, you can inject millions of cells at a time. Second, electroporation has almost no biological or chemical side effects compared to chemical substances. Third, because electroporation is a physical method that relies less on cell types and is therefore widely used. In fact, for most cell types, the transfer efficiency of genes using electroporation is much higher than that of chemical methods. A number of scientific studies have confirmed the role of electroporation in transgenic research and clinical research. For example, Diego Laderach, et al [4] used BTX ECM830 to electroplate DC cells with square wave waveforms, and transfected siRNA to study the function of localized genes in vivo. Similar methods for studying a gene are quite mature; and Annelies EP, et al [5] used BTX ECM2001 alternating current array cells and direct current to achieve stable expression of the target gene and good fusion of embryonic cells, and finally obtained Genetically modified cows, etc. The BTX ECM2001 Cell Electrofusion & Electroporator has been included in the standard experimental procedure by the US authoritative laboratory Cold Spring Port.
Transgenic animals can establish animal models of various diseases to study the pathogenesis and treatment of these diseases, and the application of electroporation technology can specifically prepare resistant drugs; and through the intersection of chemistry and electrochemical therapy injection Anticancer drugs for the treatment of skin type tumor diseases. Transgenic animal technology combined with electroporation technology can also transform the animal's genome, so that the economic characteristics of livestock and poultry can be improved more effectively, such as increasing growth rate, increasing lean meat rate, improving meat quality, improving feed utilization rate, and enhancing disease resistance. The significance of the protection of animal genetic resources is more profound and essential to the rescue of endangered species.
3. Genetically modified plants In recent years, in the face of many agricultural problems caused by the drastic changes in the global environment, such as the reduction of cultivated land area and the decline of air quality, the methods for early improvement of varieties have become outdated, forcing GM technology to fully consider various factors to reach the population. Increasing demand for plants, including food and other foods. Genetic recombination, one of the genetic engineering application techniques, can be used for artificially shearing, combining, and splicing different biological genetic materials in vitro, so that the genetic material can be recombined, and then transferred into microorganisms or cells through carriers such as microorganisms and viruses. "Asexual reproduction" and the expression of the desired gene in the cell, producing the substances required by humans or creating new species.
In recent years, some "transgenic crops" have emerged abroad, such as anti-corrosive tomatoes, herbicide-resistant cotton, anti-viral cucumbers and potatoes, and insect-resistant corn. These are all using transgenic technology to transfer the target gene into the recipient plant, using electroporation methods, gene guns or traditional Agrobacterium infection. The gene gun method is more efficient but expensive; traditional Agrobacterium infection is easy to pollute and inefficient, and there are many external uncertainties. In comparison, most studies use electrotransfection to obtain transgenic plants, such as James Saunders. Transgenic soybeans were obtained using a BTX630 electrorotator [6].
Transgenic plants can be obtained by protoplast fusion, which may change some of the genetic characteristics of plants, not only improve crop characteristics, but also cultivate high yield, high quality, anti-virus, insect-resistant, cold-resistant, drought-resistant, anti-caries, anti-salt, New crop varieties resistant to herbicides. Moreover, transgenic plants or cells cultured in vitro can be used to produce expression products of foreign genes, such as human auxin, insulin, interferon, interleukin 2, epidermal growth factor, hepatitis B vaccine, etc., which have been expressed in transgenic plants. .
Conclusion:
The continuous development of transgenic technology has greatly promoted the theoretical research and practical application of the transgenic field, especially the promotion of new varieties of transgenic plants and animals. China has launched a major science and technology project for the cultivation of new varieties of genetically modified organisms. As these scientific research results are transformed into productive forces, China's social and economic development will be greatly promoted.
references:
[1] Neumann, E., Schaefer-Ridder, et al. Gene transfer into mouse lyoma cells by electroporation in high electric fields. EMBO J, 1982; 1:841–845.
[2] Simon, JR Transformation of intact yeast cells by electroporation. Methods Enzymol, 1993; 217: 478–483.
[3] S. Tollefsen, et al. DNA injection in combination with electroporation: a novel method for vaccination of farmed ruminants. Scandinavian journal of immunology, 2002; 57: 229-238.
[4] Diego Laderach, et al. RNA Interference Shows Critical Requirement for NF-kβ p50 in the production of IL-12 by Human Dendritic cells. The Journal of Immunolgy, 2003; 1750-1757.
[5] Annelies EP, et al. Nuclear Transfer and Electrofusion in Bovine In Vitro-Matured/In Vitro-Fertilized Embryos: Effect of Media and Electrical Fusion Parameters. Molecular Reproduction, 1993; 36: 307-312.
[6] James Saunders, et al. Rapid optimization of Electroporation Conditions for Plant Cells, Protoplasts and Pollen. Molecular Biotechnology, 1995; 3:181-190.