Cell engineering can be divided into chromosome engineering, genome engineering, cytoplasm engineering and cell fusion engineering according to the design requirements and the different operation levels of genetic material to be transformed.
(1) Chromosome engineering Chromosome engineering is to add or delete chromosomes of one organism or replace them with chromosomes of other organisms according to people's needs. It can be divided into animal chromosome engineering and plant chromosome engineering. Animal chromosome engineering mainly uses micro-manipulation of cells (such as micro-cell transfer) to achieve the purpose of gene transfer. At present, plant cell engineering mainly uses traditional methods such as hybrid backcross to achieve the purpose of adding, eliminating or replacing chromosomes.
(2) Genome Engineering Bundle chromosome engineering is an overall technology to change the number of chromosomes. Since 1937 colchicine was used in biology, polyploid work has developed rapidly, such as obtaining tetraploid wheat and octoploid triticale.
(3) Cytoplasmic engineering, also known as cell disassembly engineering, is to separate cytoplasm from nucleus by physical or chemical methods, and then recombine cytoplasm between different cells to rebuild new cells, which can be used in basic research and breeding to study the relationship between nucleus and cytoplasm.
(4) Cell fusion engineering is a process of fusing two or several different cells into one cell by natural or artificial methods. It can be used to produce new species or strains (mostly used in plants, less used in animals) and monoclonal antibodies. Among them, monoclonal antibody technology uses cloned hybridoma cells to secrete high-purity monoclonal antibodies, which has high practical value and broad application prospects in the diagnosis and treatment of diseases.
Large-scale cell culture can be divided into three levels: single cell culture, tissue culture and organ culture Plant cell and protoplast culture technology can be used for breeding and rapid propagation of various plants, and plays an important role in cultivating non-toxic seedlings, long-term preservation of seeds and production of secondary metabolites. Animal cell culture technology can be used to prepare many valuable cell products, such as vaccines and growth factors. Drugs and drugs can be detected by cell culture system. Some cultured cells can be used for treatment.
Cell engineering has penetrated into many fields of human life, and achieved many research results, some of which have been popularized in production and received obvious economic and social benefits. With the deepening of cell engineering technology research, its prospect and influence will become increasingly apparent.
cell engineering
Open classification: science, scientific research, genetic engineering, cell engineering, cell biology.
Cell engineering refers to a comprehensive science and technology that uses the principles and methods of cell biology and molecular biology to change the genetic material in cells or obtain cell products at the level of whole cells or organelles according to people's wishes through some engineering means. According to different cell types, cell engineering can be divided into plant cell engineering and animal cell engineering.
Plant cell engineering
Common technical means: plant tissue culture and plant somatic hybridization.
Theoretical basis: totipotency of plant cells.
Plant tissue culture
The application scope of plant tissue culture technology: rapid propagation, virus-free plant culture and large-scale plant cell culture to produce drugs, food additives, spices, pigments and pesticides.
plant somatic hybridization
Plant somatic hybridization is a method to fuse two kinds of somatic cells from different plants into hybrid cells and culture the hybrid cells into new plants.
Animal cell engineering
Common technical means: animal cell culture, animal cell fusion, monoclonal antibody, embryo transfer, nuclear transfer, etc. Animal cell culture technology is the basis of other animal cell engineering technologies.
animal cell culture
Animal cells can secrete protein, such as antibodies. However, the amount of protein secreted by a single cell is very small, and a large number of secreted proteins can be obtained through large-scale animal cell culture.
Application of animal cell culture technology
Produce many valuable biological products in protein, such as virus vaccine, interferon and monoclonal antibody.
cell fusion
The most important application of animal cell fusion technology is to prepare monoclonal antibodies.
monoclonal antibody
In order to obtain a large number of monoclonal antibodies, it is necessary to use a single B lymphocyte for asexual reproduction, that is, to form a cell group through cloning, which may produce an antibody with single chemical properties and strong specificity-monoclonal antibody.
Application of monoclonal antibody
Biological missiles bring drugs to cancer cells, destroy cancer cells and do not harm healthy cells.
With the development of biotechnology today, cells have become a paradise for scientists to play their imaginations at will, and they can even assemble life like building blocks. Play a life combination game at the cellular level. Among them, the most representative life combination games are the masterpieces of Professor Klebert L. Maget and Professor Robert M. Peters of Yale University in the United States. When the fertilized eggs of black-haired mice, white-haired mice and yellow-haired mice divide into eight cells, they suck the embryos of eight cells out of the fallopian tubes with special straws, and then use an enzyme to dissolve the mucus wrapped in each embryo. Then put the 8-cell embryos of these three kinds of mice in the same solution and make them assemble into a 24-cell "assembled embryo". Maget and Peters transplanted the "assembled embryo" into the uterus of a mouse. Soon, a strange assembled mouse came out. It was covered with three different colors of fur: yellow, white and black. So far, in addition to assembling mice, Britain and the United States have also successfully assembled chimeras of sheep and goats.
Application of cell engineering
As a scientific research method, cell engineering has penetrated into all aspects of bioengineering and become an indispensable supporting technology. In the fields of agriculture, forestry, horticulture and medicine, cell engineering is making great contributions to mankind.
1. Food and vegetable production
Using cell engineering technology for crop breeding is one of the most beneficial aspects to human beings so far. China has reached the world advanced level in this field, and nearly 100 rice varieties or strains have been cultivated through anther haploid breeding, and about 30 wheat varieties have been cultivated. Among them, the new wheat varieties cultivated by Henan Academy of Agricultural Sciences have excellent characteristics such as lodging resistance, rust resistance and powdery mildew resistance.
In conventional cross breeding, it usually takes 8 ~ 10 years to breed a new variety, but culturing hybrid anthers in vitro with cell engineering technology can greatly shorten the breeding cycle, generally 2 ~ 3 years in advance, and is conducive to the screening of excellent characters. The micro-propagation technology introduced in the early stage is also widely used in agricultural production, with mature technology and great economic benefits. For example, it has been solved in China. Kirin Company of Japan has been able to cultivate a large number of virus-free mini-potatoes as seed potatoes in 1000 liter containers, realizing the automation of seed potato production. Through the genetic variation of plant somatic cells, various mutants with economic significance were screened out, which played an important role in creating germplasm resources and cultivating new varieties. Now, high-quality tomato, cold-resistant flax, rice, wheat, corn and other new strains have been cultivated. It is hoped that this technology can improve the quality of crops.
Vegetables are indispensable ingredients in human diet, providing essential vitamins and minerals. Vegetables are usually propagated by traditional methods such as seeds, tubers, cuttings or roots, and the cost is low. However, in some intermediate links such as introduction and breeding, variety purification and rejuvenation, and breeding, plant cell engineering technology still has great achievements. For example, the introduction of new vegetable varieties from abroad usually has only a few seeds or a few tubers and tubers at first. In order to carry out large-scale planting, a large number of breeding is needed, and micropropagation technology can be used to rapidly expand the population in a short time. In the process of conventional breeding, protoplast or haploid culture technology can also be used to rapidly propagate offspring and simplify seed production procedures. In addition, it can be combined with plant genetic engineering technology to improve vegetable varieties.
2. Garden flowers and plants
The application of cell engineering technology in fruit and forest production practice is mainly micropropagation and virus-free technology. Almost all fruit trees suffer from virus diseases, and most of them are passed down from generation to generation through asexual reproduction. Using virus-free test-tube seedling technology can effectively prevent the invasion of virus diseases, restore species and speed up reproduction. At present, the test-tube seedlings of more than ten kinds of fruit trees, such as bananas, oranges, hawthorn, grapes, peaches, pears, lychees, longan and walnuts, are virus-free. Basically mature. The micropropagation technology of banana virus-free seedlings has become one of the precedents of industrialization and commercialization. Because banana is a triploid plant, it must be propagated through asexual propagation. The traditional method generally adopts bud grafting propagation, which is seriously susceptible to diseases and has a low reproduction rate. Using virus-free micropropagation technology not only improves the quality, but also increases the yield per mu by about 30% ~ 50%, which is easy to be accepted by banana farmers.
In recent years, the research on tissue culture technology of economic trees has received great attention, which can be carried out several years earlier than the conventional methods.