Subject influence
Microbiology is an important basic course or specialized basic course for biology majors in colleges and universities, and it is also the theoretical and technical basis of modern high-tech biotechnology. Genetic engineering, cell engineering, enzyme engineering and fermentation engineering are formed and developed on the basis of microbiology principles and technologies. Microbiology is also one of the important cornerstones of the development of biology specialty and the modernization of agriculture and forestry in agricultural and forestry universities. With the wide application of biotechnology, microbiology will have a great impact on modern and future human production activities and life.
2, more absorption, fast transformation 1, small size, large specific surface area in um, but large specific surface area (surface area/volume), (insert table), there must be a huge surface for nutrient absorption, metabolic waste excretion and environmental information reception. This feature is also the key to distinguish microorganisms from all macro-organisms. For example: lactic acid bacteria:120000; Eggs:1.5; Person (200 kg): 0.3 2. The characteristics of high absorption and rapid transformation provide sufficient material basis for rapid growth and reproduction and the production of a large number of metabolites. For example: 3 grams of hamsters consume the same weight of food as their body weight every day; 1 g flashing green hummingbirds consume twice their body weight every day; Escherichia coli consumes 2000 times the weight of sugar per hour; Lactose-fermenting bacteria can decompose lactose 1 0,000 ~ 1 10,000 times its own weight within1hour, and produce lactic acid. 1 kg yeast can ferment thousands of kilograms of sugar to produce alcohol a day; 3, vigorous growth, rapid reproduction, extremely high growth and reproduction speed, for example, Escherichia coli 20-30 divides every 20-30 minutes. If the division is not stopped, the number of bacteria will increase by 2.2× 1043 within 48 hours, which will limit the growth rate. This feature can transform a large number of substrates into useful products in a short time and shorten the scientific research cycle. There are also disadvantages, such as disease and grain mildew. For example, Escherichia coli can divide once every 12.5~20 minutes under the optimum growth conditions; In liquid culture medium, the concentration of bacterial cells is generally 108~ 109 cells/ml; Brevibacterium glutamicum: shake flask seed →50 ton fermentor: the cell number can be increased by 3.2 billion times within 52 hours. Using this characteristic of microorganisms, short-term and efficient production of fermentation industry can be realized. For example, the production of fresh yeast can be harvested once every 12 hour, hundreds of times a year. Table Generation and Daily Proliferation Rate of Some Microorganisms Name of Microorganisms Generation Daily Division Times Temperature Daily Proliferation Rate
Lactic acid bacteria 38 points 38 25 2.7×1011
The score of Escherichia coli 18 was 80 37 1.2× 1024.
Rhizobia 1 10 13 25 8.2× 103.
Bacillus subtilis 3 1 score 46 30 7.0×10/3
Photosynthetic bacteria 14410301.0×103.
Saccharomyces cerevisiae 120 points12304.1×103.
Chlorella 7 hours 3.4 25 10.6
Nostoc commune * 23 hours 1.04 25 2. 1
Diatoms 17 hours 1.4 20 2.64
Paramecium 10.4 hour 2.3 26 4.92
* is the old name of Nostoc commune, which belongs to prokaryote with bacteria. 4. Strong adaptability, easy variation, extremely flexible adaptability, amazing adaptability to extreme environment, and easy variation of genetic material. More importantly, there are many kinds of physiological metabolism and metabolites of microorganisms. For example, there are microorganisms in the sedimentary rocks at a depth of 10,000 meters, an altitude of 85 kilometers, 128 meters, and 427 meters below the stratum. Number of species of microorganisms, according to 1972: low species, high species.
Viruses and rickettsia121712171217.
Mycoplasma 42 42 42
Bacteria and actinomycetes >:100015001500
Cyanobacteria122715001500
Algae150512310023100
Fungi 37 175 47300 68939
protozoan
Total 79780 98727 127298
5. Wide distribution, many kinds, wide distribution area and wide distribution environment. There are many types of physiological metabolism, and there are many kinds of metabolites. What is more important is the physiological metabolism of penicillin by microorganisms.
There are many kinds and metabolites. Microorganisms can be found in any environment where other organisms exist, and also in extreme environments where other organisms cannot survive. For example, the yield of Huang Qing mold (Huang Qing mold) is 1943, and each ml of fermentation broth contains 20 units of penicillin. Over the past 40 years, through the unremitting efforts of microbial genetic breeders all over the world, the variation of Huang Qing mold production has gradually accumulated and the fermentation conditions have been improved. At present, the fermentation level of advanced countries in the world has exceeded 50,000 units per milliliter, even close to 654.38+ 10,000 units. In animal and plant breeding, it is absolutely impossible to improve the yield through the variation and breeding of quantitative traits of microorganisms. Because of this, almost all microbial fermentation plants attach great importance to the selection of strains. Microorganism function: 1, function in natural material circulation 2, air and water purification, sewage treatment 3, industrial and agricultural production: bacteria, metabolites, metabolic activities 4, contribution to life science.
Edit the classification and naming of this paragraph.
Taxonomic units of microorganisms: phylum, class, order, family, genus and species are the most basic taxonomic units. After each taxon, there can be subphylum, subclass, suborder and subfamily ... Take beer yeast as an example. Its taxonomic status is as follows: Kindom: Phyllum: Class: ascomycetes: family: genus: yeast species: objective yeast species: it is a basic taxonomic unit. It is the general name of a large group of strains with highly similar phenotypic characteristics, extremely close genetic relationship and obvious differences from other species of the same genus. (1) strain refers to any purebred population propagated by an independent single cell and all its progeny (a group of purebred progeny flora that originated from the same ancestor of * * * and maintained its ancestral characteristics). Therefore, pure cultures of microorganisms from different sources can be called strains of this strain. This strain emphasizes genetic purity of pedigree. For example, the expression of two strains of Escherichia coli: Escherichia coli and Escherichia coli 12: If a species is the basic unit of taxonomy, then the strain is actually the basic unit of application, because different strains of the same species will have great differences in the production of enzymes or metabolites! (2) Subspecies or varieties: intra-species reclassification. When there are a few obvious and stable variation characteristics or genetic forms in different strains within a species, which are not enough to distinguish them into new species, these strains can be subdivided into two or more small taxonomic units-subspecies. Variety is synonymous with subspecies, because the word "variety" is easy to cause confusion in meaning. After 1976, the word "variant" is no longer used. Mutant strains obtained in the laboratory are usually called subspecies. For example, E.coli k 12 (wild type) does not need special aa, but after laboratory mutation, a deletion aa can be obtained from k 12, which is called a subspecies of E.coli k 12. (3) Form: often refers to the subdivision below subspecies. When the differences between different strains within the same species or subspecies are not enough to be divided into new subspecies, they can be subdivided into different types. For example, the names of different serotypes of microorganisms are divided according to the differences in antigen characteristics: there are two kinds of microbial names: common names and scientific names. Such as: red bread mold-Neurospora crassa; Pseudomonas aeruginosa-Pseudomonas aeruginosa. Scientific name-is the scientific name of microorganism, which is named according to the rules drawn up by the International Committee for Microbial Classification. Scientific names consist of Latin words or Latin loanwords. There are two kinds of naming of scientific names: two-name method and three-name method. (1) binomial method: scientific name = generic name+species name+(first time)+current person name+naming year generic name: Latin noun or adjective used as noun, singular, capitalized, indicating the main characteristics of microorganisms, constructed and stereotyped by microorganisms or named by scientists. Name: Latin adjective with lowercase prefix, which is a secondary feature of microorganism, such as pigment, shape, origin of microorganism or name of scientist. For example: Escherichia coli (migula) castellanietchalmers1919 Staphylococcus aureus 1884 When referring to a certain genus of microorganisms, rather than a certain species (or unspecified species) of the genus, sp. Or ssp. (representing respectively. For example, yeast. Represents a species in the genus Saccharomyces. Strain name: add numbers, place names or symbols after the plant name, for example: Bacillus subtilis 1.389As = Bacillus subtilis BF7658BF = Clostridium acetobutylicum 824.
Definition of microorganism
Modern definition: Microorganisms are the general name of all tiny organisms that are invisible or unclear to the naked eye. Organisms with small body and simple structure that can be clearly seen by optical microscope and electron microscope are collectively called microorganisms. But you can see some microorganisms, such as mushrooms and ganoderma lucidum, belonging to fungi. )
trait
Generally speaking, individuals are very small.
classify
Prokaryotes: three bacteria, three bodies. Three bacteria: bacteria, cyanobacteria and actinomycetes: mycoplasma, chlamydia and rickettsia; Eukaryotes: fungi, protozoa and microalgae. Cell-free class: virus, sub-virus (viroid, pseudovirus, prion).
Five * * * sex:
Small size and large area; High absorption and rapid transformation microorganism
; Prosperous growth and rapid reproduction; Strong adaptability and easy variation; Widely distributed and varied.
Edit this group
Prokaryotes: bacteria, actinomycetes, spirochetes, mycoplasma, rickettsia, chlamydia. Eukaryotes; fungus
, algae, protozoa. Cell-free classes: viruses and subviruses. Generally speaking, in Chinese mainland's textbooks, microorganisms are divided into the following eight categories: bacteria, viruses, fungi, actinomycetes, rickettsia, mycoplasma, chlamydia and spirochetes.
gemmule
(1) Definition: a kind of prokaryote, with short cells, simple structure, tough cell wall, dichotomous reproduction and strong aquatic property. (2) Distribution: warm and humid, rich in organic matter. (3) Structure: mainly unicellular prokaryote, with spherical and rod-shaped and spiral basic structures: cell membrane, cell wall, cytoplasm and nucleoplasm, and special structure: When a single bacterium or a few bacteria multiply in large quantities on solid medium, a daughter cell community with a certain morphological structure will be formed. Colony is an important basis for strain identification. Different kinds of bacteria.
actinomyces
(1) Definition: A kind of terrestrial prokaryote that mainly grows in hyphae and reproduces by spores.
(2) Distribution: Weak alkaline soil with low water content and rich organic matter; (3) Morphological structure: mainly composed of hyphae, including matrix hyphae and aerial hyphae (some aerial hyphae can mature and differentiate into sporophytes to produce spores); (4) reproduction: asexual reproduction is carried out by forming asexual spores; (5) Colony: dry, opaque and sexually propagated on solid culture medium.
virus
(1) Definition: An "acellular organism" composed of nucleic acid and protein, but its survival must depend on living cells. (2) structure: [font class = "apple-style-span" style = "font-family:-Webkit-monospace; font-size: 13px； Line height: normal; Blank: newline; " Protein capsid and nucleic acid (nucleic acid is DNA or RNA)[/font] (3) Size: generally about 100nm in diameter, with the maximum virus diameter of 200nm and the minimum virus diameter of 28nm. (4) Proliferation: A remarkable feature of virus life activity is parasitism. Viruses can only live in some living cells. And use the environment and raw materials in the host cell to quickly replicate and increase value. In the non-parasitic state, it is crystalline and cannot carry out independent metabolic activities. Take phage as an example: adsorption →DNA injection → replication, synthesis → assembly → release of phage-infected bacteria.
Edit the characteristics of microorganisms in this paragraph.
Chemical composition of microorganisms
Carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur and other elements.
microbial nutrition
1 water and inorganic salts 2 carbon source: any nutrient source that can provide carbon for the growth and reproduction of microorganisms 3 nitrogen source: any nutrient source that can provide necessary nitrogen for microorganisms: mainly used for synthesizing protein, nucleic acids and nitrogen-containing metabolites 4 energy source: nutrients or radiant energy that can provide initial energy for microbial life activities.
According to the classification of carbon sources and energy sources
5 growth factor: trace organic matter indispensable for microbial growth
Microorganisms that can cause human and animal diseases are called pathogenic microorganisms, and there are eight categories: 1. Fungi: cause skin diseases. Deep tissue infection. Actinomycetes: skin and wound infections. 3 spirochete: skin diseases, blood infections such as syphilis and leptospirosis. Bacteria: skin disease suppuration, upper respiratory tract infection, urinary tract infection, food poisoning, septicemia, acute infectious diseases, etc. Rickettsia: typhus, etc. Chlamydia: trachoma, urogenital infection. Viruses: hepatitis, Japanese encephalitis, measles, AIDS, etc. Mycoplasma: pneumonia, urinary tract infection. There are thousands of kinds of microorganisms in the biological world, most of which are beneficial to human beings, and only a few can cause diseases. Some microorganisms are usually not pathogenic, but can cause infection under certain circumstances, which is called conditional pathogenic bacteria. It can cause food deterioration and corruption, and it is precisely because they decompose natural objects that the material cycle of nature can be completed.
The role of microorganisms
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Some basic and important discoveries and theories of modern biology are obtained in the process of studying microorganisms or using microorganisms as experimental materials and tools. These theories include: proving that DNA (deoxyribonucleic acid) is the carrier of genetic information (three classic experiments: pneumococcal transformation experiment, phage experiment and plant virus recombination experiment). Semi-conservative replication mode of DNA (each strand of the double helix is a replication template). Interpretation of genetic code (64 codons correspond to 20 amino acids, which is the termination signal). Transcriptional regulation of genes (concept and regulation mode of opera, promoter, operon, replicon and activator). The terminator of messenger RNA and so on. Nowadays, many commonly used and universal biological research techniques rely on microorganisms, such as molecular cloning and expression of recombinant proteins in bacteria or yeast. Many medical technologies also rely on microorganisms, such as gene therapy with virus as the carrier.
Edit the position of microorganisms in the whole life world in this paragraph.
Before human beings discovered and studied microorganisms, all living things were divided into two completely different worlds-the animal kingdom and the plant kingdom. With the gradual deepening of people's understanding of microorganisms, they have experienced three-realm system, four-realm system, five-realm system and even six-realm system from the two-realm system. Until the end of 1970s, American Woese and others discovered the third life form on earth-archaea, which led to the birth of the theory of three realms of life. According to this theory, life is composed of archaea, bacteria and eukaryotes. In the illustrated phylogenetic tree, the yellow branch on the left is the bacterial domain; The brown and purple branches in the middle are archaea; The green branch on the right is the eukaryotic domain. Archaea includes Archaea, Archaea and Archaea. Bacterial domains include bacteria, actinomycetes, cyanobacteria and various other prokaryotes except archaea; Eukaryotic domain includes fungi, protozoa, animals and plants. Except for animals and plants, most other organisms belong to the category of microorganisms. It can be seen that microorganisms occupy a particularly important position in the classification of biology. Life evolution has always been the focus of attention. According to the evolutionary tree of "Cenancestor" constructed by parallel homologous genes, Brown thinks that Cenancestor, the ancestor of life, is a protozoan. Protozoa have produced two branches in the process of evolution, one is prokaryote (bacteria and archaea) and the other is prokaryote. In the subsequent evolution process, bacteria and archaea first evolved in different directions, and then prokaryotes swallowed an archaea and replaced the host RNA genome with archaea DNA, resulting in eukaryotes. From an evolutionary point of view, microorganisms are the old-timers of all living things. If the age of the earth is compared to one year, microbes will be born on March 20th, and humans will appear on the earth around 7 pm on February 3rd/kloc-0.
summary
One of the most important effects of microorganisms on human beings is the prevalence of infectious diseases. 50% of human diseases are caused by viruses. According to the data published by the World Health Organization, the incidence and mortality of infectious diseases rank first among all diseases. The history of human diseases caused by microorganisms is also the history of human beings constantly fighting against it. Great progress has been made in the prevention and treatment of diseases, but new and reappearing microbial infections continue to occur, for example, a large number of viral diseases have been lacking effective therapeutic drugs. The pathogenesis of some diseases is still unclear. The abuse of a large number of broad-spectrum antibiotics has caused strong selection pressure, which has caused many strains to mutate and produce drug resistance, posing a new threat to human health. Some segmental viruses can mutate through recombination or rearrangement, and the most typical example is influenza virus. Every time an outbreak of influenza occurs, the influenza virus will mutate from the strain that caused the infection last time. This rapid mutation has caused great obstacles to the design and treatment of vaccines. The emergence of drug-resistant mycobacterium tuberculosis has made the tuberculosis infection that was almost controlled rampant in the world. There are many kinds of microorganisms, some of which are corrupt, that is, they cause bad changes in food odor and tissue structure. Of course, some microorganisms are beneficial. They can be used to produce cheese, bread, pickles, beer and wine. Microorganisms are so small that they must be magnified with a microscope to see them. For example, for medium-sized bacteria, 1000 is only as big as a period. Imagine a drop of milk, there are about 50 million bacteria in every milliliter of rotten milk, or the total number of bacteria in every quart of milk is about 5 billion. That is, a drop of milk can contain 5 billion bacteria. Microorganisms can cause diseases, which will cause food, cloth, leather and other moldy rot, but microorganisms also have a beneficial side. It was Fleming who first discovered penicillin from Penicillium which inhibited the growth of other bacteria, which was an epoch-making discovery in the medical field. Later, a large number of antibiotics were screened from the metabolites of actinomycetes. The use of antibiotics saved countless lives in World War II. Some microorganisms are widely used in industrial fermentation to produce ethanol, food and various enzyme preparations. Some microorganisms can degrade plastics and treat wastewater and waste gas. , and has great potential of renewable resources, known as environmental microorganisms; Some microorganisms can survive in extreme environments such as high temperature, low temperature, high salt, high alkali and high radiation, and some microorganisms still exist. It seems that many microorganisms have been discovered, but in fact, due to the limitation of technical means such as culture methods, the microorganisms discovered by human beings today only account for a small part of the existing microorganisms in nature. Microorganism is very small and its structure is very simple, so people fully understand it and develop into a discipline, which is still very late compared with other disciplines. Nevertheless, people have been widely using microorganisms. Our working people have long recognized the existence and function of microorganisms, and it is also one of the few countries that used microorganisms at the earliest. According to archaeological speculation, brewing with curved tillers appeared in China 8,000 years ago, and brewing was very common in China more than 4,000 years ago. At that time, Egyptians also learned to bake bread and brew fruit wine. 2500 years ago, people in China invented fermented sauce and vinegar, and they knew how to treat digestive tract diseases with Qu. In the 6th century A.D. (Northern Wei Dynasty), Jia Sixie's masterpiece The Book of Qi Yaomin recorded in detail the techniques of koji-making, wine-making and sauce vinegar. In agriculture, although the nitrogen fixation function of rhizobia is not known, leguminous plant rotation has been used to improve soil fertility. These facts show that although people don't know the existence of microorganisms, they are already dealing with microorganisms. While applying beneficial microorganisms, it also controls harmful microorganisms. In order to prevent food from spoilage, people adopt methods such as pickling, adding sugar, drying and acidification. Smallpox is prevented by human pox in Qin Long, China. Prevention of smallpox by human pox is a great contribution of China to world medicine. This method first spread to Russia, Japan, North Korea, Turkey and Britain. 1798, the British doctor Jenner proposed to prevent smallpox with vaccinia. Microbiology, as a discipline, began with microscope, and its development has gone through three periods: morphological period, physiological period and the development of modern microbiology. Morphological observation of microorganisms began with the microscope invented by Antony van Leeuwenhock1632-1732. He was the first person to really see and describe microorganisms. His microscope was regarded as the most exquisite and excellent monomer microscope at that time. He used a microscope with a magnification of 50 ~ 300 times to see bacteria and protozoa clearly. 1695 Anthony Levin Hook collected a lot of accumulated achievements in the book Natural Secrets Discovered by Anthony Levin Hook. His discovery and description revealed a brand-new biological world-microbial world for the first time. This is of epoch-making significance in the history of microbiology.
physiological period
For example, there are a large number of bacteria in the intestines of healthy people, which are called normal flora, including hundreds of bacteria. In the intestinal environment, these bacteria are interdependent and mutually beneficial. The decomposition and absorption of food, toxic substances and even drugs, the role of flora in these processes and the interaction mechanism between bacteria are still unknown. Once the flora is out of balance, it will cause diarrhea. With the medical research entering the molecular level, people are more and more familiar with the technical terms such as genes and genetic materials. It is recognized that genetic information determines the life characteristics of organisms, including external morphology and life activities, and the genome of organisms is the carrier of these genetic information. Therefore, understanding the genetic information carried by the genome of an organism will be of great help to reveal the origin and mystery of life. It is a revolution to study the variation, virulence and pathogenicity of microbial pathogens at the molecular level. Microbial genome research, represented by the Human Genome Project, has become the frontier of the whole life science research, and microbial genome research is one of the important branches. Science, an authoritative magazine in the world, once rated microbial genome research as one of the major scientific advances in the world. Revealing the genetic mechanism of microorganisms through genome research, discovering important functional genes, and developing vaccines and new antiviral, antibacterial and antifungal drugs on this basis will effectively control the epidemic of old and new infectious diseases and promote the rapid development and growth of medical and health undertakings! Studying the genome of microorganisms at the molecular level provides new clues and ideas for exploring the mystery of the interaction between individuals and groups of microorganisms. In order to fully develop microbial (especially bacterial) resources, the United States launched the Microbial Genome Research Program (MGP)65438-0994. By studying the complete genome information, we can not only deepen our understanding of the pathogenic mechanism, important metabolism and regulation mechanism of microorganisms, but also develop a series of genetic engineering products closely related to our lives, including vaccination vaccines, therapeutic drugs, diagnostic reagents and various enzyme preparations applied to industrial and agricultural production. Through the transformation of genetic engineering methods, we will promote the construction of new strains and the transformation of traditional strains, and comprehensively promote the era of microbial industry. Industrial microorganisms involve food, pharmacy, metallurgy, mining, petroleum, leather, light chemical industry and many other industries. Production of antibiotics, butanol, vitamin C and preparation of some flavor foods by microbial fermentation; Some special microbial enzymes are involved in leather depilation, metallurgy, oil extraction and mining, and even directly used as additives for washing powder. In addition, some microbial metabolites can be widely used in agricultural production as natural microbial pesticides. By studying the genome of Bacillus subtilis, a series of genes related to the production of antibiotics and important industrial enzymes were found. As an important microecological regulator, lactic acid bacteria participate in the food fermentation process.
Edit the world status of this paragraph.
Before human beings discovered and studied microorganisms, all living things were divided into two completely different worlds-the animal kingdom and the plant kingdom. With the gradual deepening of people's understanding of microorganisms, they have experienced three-realm system, four-realm system, five-realm system and even six-realm system from the two-realm system. Until the end of 1970s, American Woese and others discovered the third life form on earth-archaea, which led to the birth of the theory of three realms of life. According to this theory, life is composed of archaea, bacteria and eukaryotes. In the illustrated phylogenetic tree, the yellow branch on the left is the bacterial domain; The brown and purple branches in the middle are archaea; The green branch on the right is the eukaryotic domain. Archaea includes Archaea, Archaea and Archaea. Bacterial domains include bacteria, actinomycetes, cyanobacteria and various other prokaryotes except archaea; Eukaryotic domain includes fungi, protozoa, animals and plants. Except for animals and plants, most other organisms belong to the category of microorganisms. It can be seen that microorganisms occupy a particularly important position in the classification of biology. Life evolution has always been the focus of attention. According to the evolutionary tree of "Cenancestor" constructed by parallel homologous genes, Brown thinks that Cenancestor, the ancestor of life, is a protozoan. Protozoa have produced two branches in the process of evolution, one is prokaryote (bacteria and archaea) and the other is prokaryote. In the subsequent evolution process, bacteria and archaea first evolved in different directions, and then prokaryotes swallowed an archaea and replaced the host RNA genome with archaea DNA, resulting in eukaryotes. From an evolutionary point of view, microorganisms are the old-timers of all living things. If the age of the earth is compared to one year, microbes will be born on March 20th, and humans will appear on the earth at around 7: 00 pm on February 3rd/kloc-0! !
There are good and bad! !