Introduction to common model organisms in life science research

Model organisms play an important role in biomedical fields due to their simple structure, short life cycle, simple culture and small genome. As a material, model organisms can not only answer the most basic biological problems in life science research, but also have reference to the treatment of some human diseases. Common model organisms are yeast in fungi, Escherichia coli in prokaryotes, nematodes in lower invertebrates, Drosophila in insects, zebrafish in fish, mammals in mammals, and pseudo-southeres in plants. mustard.

1 Research history of model organisms

In early life science research, people always used some common creatures as materials. The organisms used were the purpose of research, and there was no concept of model organisms. With the development of science, more and more knowledge about life is urgently needed to systematically organize these messy knowledge and comprehensively understand the overall process of life. At the same time, people's energy is limited. It is impossible to study all the creatures one by one. This is the representative organism that has been selected for research. This is the driving force behind the emergence of model organisms. At the same time, in the medical field, because of ethical issues, some experiments are impossible to use humans as test materials, and have to find reliable alternatives, which is another driving force for the emergence of model organisms.

1.1 Arabidopsis research history

Arabidopsis thaliana belongs to the cruciferous family, like cabbage, rapeseed, and cabbage, and has no obvious economic value. Historically, the tobacco and alcohol of Arabidopsis was deliberately traced back to the 16th century. In 1943, Laibach elaborated on the advantages of Arabidopsis as a model organism and contributed to an international Arabidopsis meeting in Germany in 1965. But it has been nearly 20 years since I actually studied as a model organism. In 1986, the Meyerowitz laboratory first reported the cloning of a gene in Arabidopsis (Chang C, 1986). In 1988, the first RFLP map of the Arabidopsis genome was published. In the following years, T was reported. - cloning of a DNA insertion mutant gene, gene cloning based on a gene map, and the like. The complete sequencing of the genome (The Arabidopsis Genome Initiative. 2000) was completed in 2000, becoming the first fully sequenced plant.

1.2 Research history of C. elegans

Caenorhabditis elegans plays a pivotal role in today's life science research. In the 1960s, after establishing the central rule of molecular genetics, Brenner chose the beauty nematode, a simpler organism than Drosophila, to explore the genetic mechanisms of individual and neural development. In 1974, he published an article on Genetics, in which the genetic manipulation methods such as mutant screening and gene mapping of C. elegans were described in detail (Brenner S. 1974). It laid the foundation for the genetic research of the humanoid nematode as a model organism for individual development.

1.3 Research History of Drosophila

Drosophila melanogaster belongs to the Diptera of the Insecta. In the early 20th century, Morgan chose Drosophila melanogaster as the research object, established the genetic chromosome theory, laid the foundation of classical genetics and pioneered the use of fruit flies as a model. The first of the creatures. Significant progress has been made in the genome manipulation of Drosophila since the 1980s and a series of effective techniques have been developed. In 2000, whole-genome sequencing of Drosophila was completed, with a genome-wide genome of approximately 165 Mb (Wan YQ, 2006).

1.4 Research progress of zebrafish

The zebrafish (Danio rerio) is a kind of bony fish belonging to the genus Pteropodidae. In the 1970s, American geneticist George Streisinger noticed the advantages of zebrafish and began to study its breeding methods, embryo development, etc., and developed some related genetic techniques. A paper on the in vitro fertilization and haploid induction techniques of zebrafish was published in Nature (Streisinger G, 1981). By the early 1990s, German developmental biologist Christine Nusslein-Volhard and Dr. Wolfgang Driever of Harvard University in the United States began a large-scale chemical mutagenesis study on zebrafish (Driever W, 1996).

1.5 Research history of mice

The mouse belongs to the genus of the genus Rodentidae, and is currently widely used in the field of biomedical research, Mus musculus. In 1902, Harvard University's Castle began the genetic study of mice under the influence of Mendelian genetics research, and systematically analyzed the genetic and genetic changes of mice. In 1982, the transgenic mouse carrying the foreign gene was first reported. In 1998, one year after the birth of the cloned goat Dolly sheep, the cloned mouse was born in Hawaii. In 2002, the whole sequence of the mouse genome was sequenced. Since 2005, large-scale Gene deletion studies began in the United States, the European Union, and Canada (Lin ZY, 2006).

2 Research advantages of model organisms

In all model organisms, although they differ greatly in classification, they also share some common characteristics. First of all, these organisms have strong adaptability, easy to raise, strong fertility, and easy to obtain a large amount of test materials. Secondly, these biological environments and human health have no major harm, and will not cause damage to the experimental personnel and the ecological environment during the test.

2.1 The special advantages of C. elegans

Under natural conditions, the beauty nematode is male and female, and can produce about 300 fertilized eggs in a lifetime, which can be rapidly multiplied. At the same time, under natural conditions or induction, male individuals can be produced for hybridization experiments. This feature makes the beauty nematodes have unparalleled advantages in genetic research. In addition, of the total 1090 cells of C. elegans, 131 cells disappeared in a constant manner at fixed developmental times and fixed locations. The number of cells with a certain number of C. elegans and fixed cell apoptosis is the main reason for determining the status of C. elegans in studying apoptosis (Qin FS, 2006).

2.2 Special advantages of fruit fly

The advantages of Drosophila as a model organism research are mainly in the two aspects of biology and technology. In biology, long-term research has accumulated a lot of knowledge and information about fruit flies, and prepared a large number of mutants distributed in thousands of genes. Drosophila also has many characteristic chromosomes that carry phenotypic markers, molecular markers, or other markers that facilitate genetic manipulation. These tools allow large-scale genome screening to isolate a series of visible or lethal phenotypes, and even isolate those that are only in mutant individuals. The phenotype of the second or third generation. Technically, some effective techniques developed during Drosophila research are still only applicable to fruit flies, such as: enhancer trap technology, site-directed homologous recombination, two-component ectopic expression systems, chimera analysis. Technology and gene-based knockout techniques (Adams MD, 2002).

2.3 Special advantages of zebrafish

The zebrafish can become a model creature, and it has its own unique advantages. Biologically, zebrafish are fertilized in vitro, embryos are developed in vitro and are transparent, easy to observe and manipulate. The fertilized eggs are about 1 mm in diameter, which facilitates microinjection and cell transplantation. Technically, zebrafish can perform cell marker and cell lineage tracking like nematodes and fruit flies, and can also perform embryo cell transplantation like Xenopus. At the genetic level, transgenic technology, gene overexpression technology, random and target gene directed mutagenesis have been developed (Sun ZH, 2006).

2.4 The unique advantages of mice

Mice are mammals and are closely related to humans. This is the primary advantage of mice as a model of medical research. At the same time, the mice form a female suppository during mating, which can judge the mating time very well, which is very important for judging the development time in the study. Technically, long-term experimental research has trained a large number of experimental personnel and established extensive experimental systems such as gene traps, chemical mutagenesis, and gene-directed mutations (Lin ZY, 2006).

3 Main research areas of model organisms

3.1 Main research areas of Arabidopsis thaliana

3.1.1 Research in developmental biology

In the study of plant morphogenesis, the main results of Arabidopsis are shown in the ABC model of flower development, and A, B, and C refer to the three types of genes that control the development of different floral organs (Bowmen JL, 1991). The expression products of these three types of genes are distributed in the corresponding regions according to their respective flower organ positions. When one of the genes is mutated, the other regions of the flower will develop other types of flower organs. At the same time, in-depth research has been carried out on the development of plant roots, stems, leaves, embryos and seeds.

3.1.2 Research in Molecular Biology

miRNA is one of the most noteworthy hot spots in Arabidopsis research in recent years. A mature miRNA is a nucleotide containing only 19-23 bases. It can bind to the mRNA of some genes through base pairing, and destroy the mRNA bound to it or interfere with the translation of mRNA under the action of some enzymes (Bartel D P. 2004). In Arabidopsis, in addition to SCL1 and HYL1, there is an essential protein SERRATE (SE) involved in processing the initial transcript of miRNA. There is also an important protein HEN1 in the biosynthesis of miRNAs (Park W, 2002). These two studies provide valuable information for a complete understanding of miRNA biosynthesis processes in higher organisms.

3.2 Main research areas of nematodes

3.2.1 Cell biology

In the lifetime of Caenorhabditis elegans, 12% of cells disappear by the form of apoptosis, and 80% of them occur in the embryonic developmental stage. Now, by studying individual mutants, it has been shown that apoptotic genes control apoptosis by genetically constituting a linear regulatory pathway (Horvitz H R. 2002). By constructing double deletion mutants between these genes or performing transgenic analysis, it was found that the genetic regulatory pathways of their composition were: egl-1→ced-9→ced-4→ced-3, of which ced-9 and ced-3 The gene products correspond to the mammalian apoptosis inhibitor Bcl-2 and the caspase, a class of enzymes that perform apoptosis, respectively.

3.2.2 RNAi and its mechanism of action

The discovery of RNAi and its genetic mechanisms is another major contribution of C. elegans to the development of contemporary life sciences. The discovery of RNAi began 30 years ago when antisense RNA was found to inhibit the translation of endogenous mRNA (Fire A, 1998). The discovery of RNAi and miRNA provides a potentially new approach to disease treatment.

3.3 Main research areas of fruit flies

3.3.1 Research in biology

As a classical model organism of genetics research, Drosophila was mainly used to clarify the basic principles and concepts of eukaryotic genetics. After the 1970s, Drosophila was widely used in the study of developmental biology, such as embryonic development (Nusslein-Volhard C, 1980), the formation of various organs (Lengyel JA, 2002), the development of the nervous system, and advanced neural activity. Behavioral mechanisms, etc. (Guo JZ, 2005).

3.3.2 Research on Drosophila in Human Diseases

Among the human diseases studied using the Drosophila model, most of the current studies are neurodegenerative diseases, including Parkinson's disease (Feany MS, 2000), Alzheimer's disease (Ye YH, 1999), polyglutamine. Disease (Steffan JS, 2004) and Fragile X Syndrome (Zhang YQ, 2001). In addition, Drosophila can also be used as a research model for tumors, cardiovascular diseases, and mitochondrial diseases.

3.4 Main research areas of zebrafish

3.4.1 Research in biology

The life cycle involves the development of embryos, the growth of growth, physiological and psychological balance, and the production, senescence, and death of germ cells. Each process is very complex, that is, regulated by genes, and also affected by external factors. Embryonic development studies using zebrafish mainly include the effects of maternal-initiated factors on initiation of embryonic development, formation of body axis, induction and differentiation of germ layers, movement of cells in embryos, development of nervous systems, formation of organs, and Asymmetric development, origin and migration of primordial germ cells (Wilson SM, 2004).

3.4.2 Application in human diseases

Zebrafish belong to vertebrates, and their growth and development, tissue system structure and humans have high similarity. The two are also highly conserved in the structure and function of genes and proteins. Therefore, zebrafish is also studying the mechanism of human diseases. The fine model creature. Some mutants of Bama fish have been identified, and their phenotypes are human diseases. For example, the sau mutant is similar to the congenital iron granulocyte anemia caused by the mutation of the human ALAS-2 gene, the yqu mutant is similar to human erythrocyte porphyria, and the gridlock mutant is similar to human congenital arterial vasoconstriction. Etc. (Sun ZH, 2006).

3.5 main research areas of mice

As the only model organism in mammals, mice play an important role in human physiology and pathology research. According to classical genetics, more than 100 recombinant inbred lines are being established (Cox RD, 2003). By comparing the linkages between these inbred lines and their inbred lines in physiological and biochemical phenotypes and genotypes, we are expected to The regulation of complex traits allows for in-depth genetic analysis to discover the pathogenesis of complex diseases. At the same time, through the large-scale gene deletion research, the establishment of deletion gene mouse strains, analysis of gene function, is also a hot spot in mouse research.

16"13g Dip Paint Plain Caper Hanger /we Love Caper Hanger

Gold Dip Paint Plain,Accept Custom Design Cape Hanger,Wholesale Custom Cape Hanger,Not Easy Break Cape Hanger

SHAOXING DINGLI METAL CLOTHESHORSE CO., LTD , https://www.dingliclothrack.com