The first part of academic papers on genetic engineering
Genetic engineering is a brand-new biotechnology science born on the basis of the comprehensive development of molecular biology and molecular genetics in 1970s. Genetic engineering is a complex biotechnology. The genes of one organism can be transferred to another cell, and even the genes of bacteria, animals and plants can be exchanged. When a gene enters another cell, it will change some functions of this cell. This project has created a recombinant gene that does not exist in nature. It not only brings new hope to the pharmaceutical industry, improves the crop yield in agriculture, but also provides solutions to environmental pollution and energy crisis, and can even be used for criminal case investigation. What is the present situation and prospect of genetic engineering, and what are its advantages and disadvantages?
Key words: genetic engineering; Development status; Development prospect; Advantages and disadvantages of genetic engineering
First, genetic engineering.
(A) the concept and development of genetic engineering
1. concept
Genetic engineering, also known as gene splicing technology and DNA recombination technology, is based on molecular genetics, using modern methods of molecular biology and microbiology, constructing hybrid DNA molecules in vitro according to pre-designed blueprints, and then introducing living cells to change the original genetic characteristics of organisms, obtaining new varieties and producing new products.
2. Development
Biologists discovered the double helix structure of DNA in 1950s, and further understood the material carrier of human and other biological inheritance from the microscopic level, which was a major breakthrough in human biological research. After the 1960s, scientists began to decipher the genetic code of biological genetic genes, in short, to find out the nucleotide sequence of each gene that controls biological genetic characteristics. On the basis of understanding the nucleotide sequence of some single genes, all gene maps of important organisms such as human beings and rice were sequenced and interpreted in a planned and large scale.
(B) the development status and prospects of genetic engineering
1. Development status
(1) Genetic engineering is applied to agriculture. Using genetic engineering method to transfer specific genes into crops to construct transgenic plants has the advantages of pest resistance, stress resistance, preservation, high yield and high quality.
Here are several representative methods.
① Improve the nutritional value of crop products, such as increasing the protein content of seeds and tubers and changing the proportion of essential amino acids in plant protein.
② Improve the stress resistance of crops, such as insect resistance, drought resistance, waterlogging resistance and herbicide resistance.
③ Genetic engineering of biological nitrogen fixation. If non-leguminous plants such as cereals can be transformed into rhizobia or have nitrogen fixation ability, they will replace countless nitrogen-fertilizer plants. ④ Increase the yield of plant secondary metabolites. Plant secondary metabolites constitute 25% of the world's pharmaceutical raw materials, such as quinine for malaria, vincristine for leukemia, scopolamine for hypertension, morphine as an anesthetic and so on.
⑤ Using transgenic animal technology to cultivate new animal husbandry varieties.
Second, the application of genetic engineering in medicine
At present, the genetic engineering application industry led by genetic engineering drugs has become one of the fastest growing industries in the world, with broad prospects. Genetic engineering drugs mainly include cytokines, antibodies, vaccines, hormones and oligonucleotides. It plays an important role in preventing human tumors, cardiovascular diseases, hereditary diseases, diabetes, and various infectious diseases including AIDS and rheumatoid diseases. Interferon (IFN), which we are most familiar with, is a multifunctional cytokine developed by genetic engineering technology. Clinically, it has been used to treat leukemia, hepatitis B, hepatitis C, multiple sclerosis and rheumatoid arthritis. And the AIDS vaccine developed by genetic engineering has completed the pilot test and entered the clinical verification stage; Specially used to treat tumors? Tumor gene missile? It will also be developed in the near future. It can purposefully find and kill tumors and make it possible to cure cancer.
Thirdly, the application of genetic engineering in environmental protection
The environmental pollution caused by industrial development and other human factors has far exceeded the purification ability of natural microorganisms. Genetic engineering technology can improve the ability of microorganisms to purify the environment. By using DNA recombination technology, the genes of four strains degrading aromatic hydrocarbons, terpenoids, polycyclic aromatic hydrocarbons and aliphatic hydrocarbons were connected and transferred to a certain strain, and a strain capable of degrading four kinds of organic compounds at the same time was constructed. Super bacteria? It can completely degrade 2/3 hydrocarbons in the oil slick in a few hours, while natural strains need 1 year. DNA recombination technology, which came out in the late 1990s, can innovate genes, endow expression products with new functions and create brand-new microorganisms. For example, all genes of different bacteria that degrade a pollutant can be cloned by PCR technology, then treated and recombined in vitro by gene recombination technology, and finally introduced into a suitable vector, so that it is possible to produce one or several super strains with extraordinary degradation ability, thus greatly improving the degradation efficiency.
(A) Development prospects
The application of genetic engineering recombinant DNA technology to cultivate grain crops with improved characters has achieved initial results. A remarkable feature of recombinant DNA technology is that it can make an organism acquire new functions completely unrelated to its inherent traits, thus causing revolutionary changes in biotechnology and enabling people to produce mammals in a large number of expanded cells, which is undoubtedly of great significance. A large number of useful drugs can be easily extracted by cloning the target genes that control the synthesis of these drugs and transferring them into Escherichia coli or other organisms for effective expression. At present, many successful cases have been achieved in this field, the most prominent of which is the production of recombinant insulin. Recombinant DNA technology has also strongly promoted the development of medical research. It affects many sciences, such as clinical diagnosis of diseases, gene therapy of genetic diseases, development of new vaccines and research on cancer and AIDS, and has made considerable achievements.
(B) the advantages and disadvantages of genetic engineering
1. The benefits of genetic engineering
Genetic diseases are caused by the wrong genes of the father or mother. Gene screening method can quickly diagnose the error of gene coding; The rule of gene therapy is to use genetic engineering technology to treat such diseases. Prenatal genetic screening can diagnose whether the fetus has genetic diseases. This screening method can even diagnose embryos fertilized in vitro, which are at least two days old and still in eight cell stages. The method is to take out one of the cells, extract DNA, test whether its gene is normal, and then decide whether to implant the embryo into the mother's uterus for development. Fetal sex can also be measured. Gene screening will not change people's genetic makeup, but gene therapy will. At present, the whole world is paying attention to the development of sustainable agriculture, hoping that agriculture will not only have economic benefits, but also be endless and will not destroy the ecological environment. Genetic engineering can help solve this kind of problem. Genetic engineering can improve the nutritional composition of crops or enhance the resistance to pests and diseases. It can improve the growth rate of livestock and poultry, the milk yield of cattle and sheep, and improve the meat quality and fat content.
2. Disadvantages of genetic engineering
Large-scale genetic screening will cause a series of social problems. Although genetic screening can help doctors treat patients earlier and more effectively, it may hinder their future life and employment. What will genetic engineering produce? Insecticide? Some crops may also be harmful to the environment. They may kill unexpected beneficial insects and affect the ecological balance of insects. Genetically modified foods are different from traditional foods of the same biological origin. The change of genetic traits may affect the composition of protein in cells, which may lead to the change of component concentration or the formation of new metabolites. Therefore, it may produce toxic substances or cause allergic symptoms. Some people even suspect that genes will be transferred in the human body, resulting in unimaginable consequences. The potential hazards of genetically modified food include: the production of new toxins and allergens in food; Other harmful health effects caused by unnatural foods; Chemicals used in crops increase the pollution of water and food; Will produce herbicide-resistant weeds; The spread of diseases transcends species barriers; Loss of crop biodiversity; Ecological balance is out of balance.
Four. Concluding remarks
With the progress of social science and technology, the development of genetic engineering will become inevitable. Although it will bring us some harm, it will still bring us many benefits. It not only provides us with new energy, but also promotes the economic development of all countries. Therefore, while developing genetic engineering, we should try our best to avoid some hazards and make the beneficial aspects be applied as much as possible.
References:
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In 20001year, the global sales of EPO reached 2 1. 1 billion dollars, 2.68 billion dollars in 2002 and 5 billion dollars in 2003. It is the most successful genetic engineering drug at present and the largest single variety of bioengineering drugs. Most patients who have used EPO feel good, and there are no obvious side effects or dysfunction during the treatment. Recombinant CHO cells can be scaled up to production scale to meet the demand for EPO.
2 insulin
Since 192 1 year Wanjin and others successfully extracted insulin and applied it in clinic, it has saved the lives of countless diabetic patients. In 2000 alone, insulin prolonged the life span of about 565,438+0 million patients with type I diabetes worldwide. In the early 1980s, human insulin once again became a commercial reality. In the late 1980s, human insulin was successfully synthesized by gene recombination technology, and insulin was expressed in Escherichia coli and yeast as host cells [7].
Only Lilly Company, Novo Nordisk Company, Aventis Company and China Beijing Li Gan Biotechnology Co., Ltd. can industrially produce human insulin at home and abroad, and insulin analogues are only produced in the above four countries, and each company can only produce a powerful or quick-acting simulated towel, mainly because the industrialization of biosynthetic human insulin is extremely difficult to achieve, and it cannot be achieved without mature high-density fermentation technology, purification technology and industrial production experience [8].
3 vaccine
In human history, there have been many kinds of epidemics that have caused huge losses of life and property, and vaccines have played a very key role in the process of preventing and eliminating these epidemics. Therefore, the vaccine was rated as one of the most important discoveries in human history.
Vaccines can be divided into two categories: traditional vaccines (additional vaccines) and new vaccines (new generation vaccines) or high-tech vaccines (high-tech vaccines). Traditional vaccines mainly include attenuated live vaccines, inactivated vaccines and subunit vaccines, while new vaccines are mainly genetically engineered vaccines. The role of vaccines has also developed from simply preventing infectious diseases to preventing or treating diseases (including infectious diseases), and both prevention and treatment are equally important [2].
With the development of science and technology, great progress has been made in the research and development of vaccines against diseases that seriously threaten human life, such as AIDS, cancer and hepatitis, which also breeds great business opportunities [9]. In 2007, global vaccine sales reached $654.38+063 billion. According to the research report issued by Merrill Lynch, the global vaccine market is growing at a sustained growth rate of over 654.38+03%. China is an emerging market for vaccines, and the domestic vaccine market has great development potential, with an annual growth rate exceeding 15%.
Vero cells, BHK2 1 cells, CHO cells and Marc 145 cells are the most commonly used cells in the production of vaccines and antibody drugs based on cell culture, and the reactor large-scale culture technology of these cells supports the technical level of the industry. At present, it is the focus of international vaccine industry research to establish a technical platform for cell culture and protein expression and further improve the supporting technology of vaccine production under the background of bioreactor.
4 antibody
Functionally, antibodies can be divided into therapeutic antibodies and diagnostic antibodies; According to the structural characteristics, antibodies can be divided into monoclonal antibodies and polyclonal antibodies. Antibodies can effectively treat various diseases, such as autoimmune diseases, cardiovascular diseases, infectious diseases, cancer and inflammation [10,1]. A major feature of antibody drugs is their low toxicity, which can even be ignored. Another advantage is that antibodies themselves can be used as therapeutic weapons and drug delivery tools. Besides humanized antibody, conjugated antibodies related to small molecule drugs, toxins or radioactive payloads also show great potential in theory, especially in cancer treatment [12].
Therapeutic antibody is a kind of biotechnology drug with the highest sales volume in the world. In 2008, the sales of therapeutic antibodies exceeded $30 billion, accounting for 40% of the whole biopharmaceutical market. Among the 99 biotechnological drugs approved by the United States, 30 are antibody drugs; Among 633 biotechnological drugs in clinical research, 192 are antibody drugs, and therapeutic antibodies account for half of the research on anti-cancer and autoimmune diseases [2]. As of 2007, the antibody drugs approved by FDA in the United States are shown in Table 2 [13].
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Zhu Zulin, Zhu Yumei, Wang Xiaohong. Application of recombinant human erythropoietin in the treatment of uremia [J]. China Journal of Cancer Prevention, 2002. Blood,1997,89 (12): 4248-4267.
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Xu Weiliang. Research on Optimization of Biological Products Supply Chain and Shortening Supply Lead Time ―― Based on the Case Analysis of Vaccine Department of GlaxoSmithKline (China) (Master's Degree Thesis). Shanghai Jiaotong University, 2005.
[ 10] Presta LG。 Molecular Engineering and the Design of Therapeutic Antibodies [J].Curr Opin Immunol, 2008,20 (4): 460.
[1 1] Liu XY, Pop LM, Vitetta ES. Engineering therapeutic monoclonal antibody [J]. Immunology Review, 2008, 222: 9.
Chen Zhinan. Prospect of biopharmaceutical industrialization in China based on antibody. China pharmaceutical biotechnology [J]. 2007, 1( 1): 2.
Yu, Daming Chen, Present situation and development trend of antibody drugs [J]. Biotechnology. 2009, 1 (3): 49.
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