Microbiology

Microbiology is a branch of biology. It studies the morphology, structure, life activities and laws of microorganisms under certain conditions, and studies the evolution, classification and interactions with humans, animals, plants and nature. A science. The task of microbiology workers is to use microbes that are beneficial to humans for production practices, while at the same time transforming, controlling or eliminating microbes that are harmful to humans, and making microbiology in the direction of human needs. Microorganisms are tiny organisms that exist in nature and are small in shape, simple in structure, and invisible to the naked eye. They must be magnified several hundred times, thousands of times, or even tens of thousands of times by optical microscopes or electron microscopes. Although they are small in size, they have certain morphological structure, rapid reproduction, easy mutation, many types of nutrition, and strong environmental adaptability. It is widely distributed in nature, and there are a large number of microorganisms in rivers, rivers, lakes, oceans, soils, air, and mineral deposits. There are also a variety of microbial parasites in humans, the surface of animals and plants, and the channels of the respiratory tract, digestive tract, etc. that communicate with the outside world. Microbial species are very complex, including bacteria, viruses, chlamydia, rickettsia, mycoplasma, spirochetes, actinomycetes and fungi. Except for non-cell type viruses, they belong to the primitive world. According to the difference in cell structure and composition, it can be divided into two major categories: prokaryotic cell type and eukaryotic cell type. Therefore, microorganisms include: 1 Non-cell type microorganisms: Viruses are non-cell type microorganisms, which are composed of nucleic acid (DNA or RNA) and protein shells, and some have a lipid envelope. It is small in size and can pass through a sterilizing filter. Generally, it cannot be observed under an optical microscope. It must be magnified thousands of times to tens of thousands of times by an electron microscope; it is a microorganism that is strictly parasitic in a susceptible cell and replicates in a replicating manner. In recent years, it has been found that there is no protein shell, only the virus of naked nucleic acid. 2 prokaryotic microbes: only the original nucleus, no nuclear membrane and nucleoli, no mitosis, lack of organelles. Prokaryotic microorganisms include bacteria, chlamydia, rickettsia, mycoplasma, spirochetes and actinomycetes. 3 eukaryotic cell type microorganisms: The nuclear nucleus is highly differentiated, with nuclear membrane and nucleolus, capable of mitosis, and complete organelles in the cytoplasm. For example, the fungus is a eukaryotic microorganism. Microorganisms in nature are not only diverse but also numerous in number and function. Most are beneficial to people, animals and plants, and are necessary. Many substances are cycled by the action of microorganisms. For example, ammoniated bacteria in the soil decompose organic nitrides to produce ammonia, promote the growth of nitrite bacteria, nitrite bacteria oxidize ammonia to form nitrite, provide metabolic materials for nitrate bacteria, and nitrate bacteria. Oxidizing nitrite produces nitrate, which is needed for plant growth and development. Plants are used by humans and animals. It can be seen that without microorganisms, plants cannot be metabolized, and humans and animals will not survive. In agriculture, in addition to the application of 5406 actinomycetes and nitrogen-fixing bacteria that have the functions of disease resistance, growth promotion and fertilizer efficiency, we also use the natural phenomenon of microbial insecticide to fight pests. For example, Bacillus thuringiensis can grow and reproduce in the intestines of some pests, secreting toxins and killing pests. This kind of bacteria has a good killing effect on pine caterpillars, apple nest moths, corn borers and other pests. For example, Beauveria bassiana, Penicillium, and Acaricidal bacteria are used to kill pests such as soybean borer, cabbage caterpillar, and rice borer. Use insect viruses to control forest pests and crop pests. Since these microbial pesticides are safe for humans, livestock and crops, they have become an active research field in biological control and are currently being widely used. In short, a new way to increase production by microbial fertilization, growth, disease prevention, and treatment has been opened. In the industrial sector, in the food, leather, textile, petroleum, chemical, metallurgical and other sectors, the application of microorganisms is also more and more extensive. For example, the use of microorganisms for petroleum dewaxing provides a variety of low freezing point petroleum products to meet the needs of industry and national defense. For example, in the production of MSG, the microbial fermentation method is used instead of the hydrochloric acid hydrolysis method. The original production of 1 ton of MSG requires 30 tons of wheat, and now only 3 tons of hawthorn powder is needed, which not only improves production efficiency, reduces costs, but also saves grain. In terms of sewage treatment, the use of microorganisms to treat phenol, organic phosphorus and printing and dyeing wastewater has received good results. Some progress has also been made in the treatment of cyanide-containing wastewater. How to use the function of microorganisms to transform harmful substances, turn harm into profit, turn waste into treasure, protect and control the natural environment, has been increasingly valued by people. In the pharmaceutical industry, almost all antibiotics are metabolites of microorganisms. After liberation, China has successfully produced more than 50 kinds of antibiotics such as gentamicin, chunremycin, wangguangmycin, and found new antibiotics such as innovativemycin in China. In recent years, the development of bacterial fermentation to produce ATP and other drugs has played an important role in safeguarding people's health. Microorganisms that are parasitic in the mouth, nose, throat, and digestive tract of humans and animals. They are harmless, and some are resistant to certain pathogenic microorganisms; microorganisms living in the intestines can synthesize nutrients that are indispensable to humans— - thiamine, riboflavin, niacin, vitamin B12, vitamin K and other vitamins and a variety of amino acids. The stomach of ruminants such as cows and sheep can be digested by cellulose-decomposing microorganisms to digest cellulose in the forage. Leguminous plants are symbiotic with Rhizobium, so that free N2 in the air can be utilized as a nitrogen source. In addition, some microorganisms can cause human or animal and plant diseases. These pathogenic microorganisms are called pathogenic microorganisms, which can cause diseases of crops such as rice blast, wheat scab and the like. The diseases caused by livestock and poultry include chicken cholera, duck plague, bovine anthrax, and swine fever. Certain pathogenic microorganisms can cause human infectious diseases such as typhoid fever, bacillary dysentery and influenza. Some microorganisms, under normal conditions, do not cause disease, and under certain conditions, can cause diseases called conditional pathogenic microorganisms. In addition, the destructive nature of microorganisms is also caused by corrosion, mildew, etc. of industrial products, agricultural and sideline products, and daily necessities. The simple structure of microorganisms, rapid growth and reproduction, easy cultivation and the convenience of application of mutants make them a good material for many basic problems in research biology, and play an important role in exploring the nature of life, the origin and evolution of life. And often associated with branch biology, so it is not only an applied science, but also a very important basic science. Microorganisms are closely related to humans, and the scope of research is increasingly broad and deep. Therefore, microbiology has formed some sub-disciplines. Emphasis is placed on the basic issues of microbiology, such as general microbiology, microbial taxonomy, microbial physiology, microbial ecology, microbial genetics, and the like. According to the type of research object, it can be divided into bacteriology, virology, mycology, and the like. In the application of microorganisms, there are agricultural microbiology, industrial microbiology, medical microbiology, veterinary microbiology, food microbiology, petroleum microbiology, marine microbiology, soil microbiology. The mutual cooperation of each branch discipline promotes each other and is conducive to the comprehensive and in-depth development of microbiology. References: Edited by the Chinese Medical Encyclopedia Editorial Board; Yu (He) Editor-in-Chief. Chinese Medical Encyclopedia·19 Microbiology. Shanghai: Shanghai Science and Technology Press, 1992. 1-2.