Auricularia auricula; Fungi
Heterotrophs with eukaryotes and cell walls. There are many species and genera, with 654.38+100,000 reported genera and 654.38+100,000 species. Except for a few lower types of single cells, most of its vegetative bodies are composed of slender tubular mycelium. The hyphae of lower fungi have no septa, while those of higher fungi have septa. The former is called partition, and the latter is called partition. In the cell walls of most fungi, chitin is the most characteristic, followed by cellulose. Common fungal organelles are: nucleus, mitochondria, microbodies, ribosomes, vacuoles, lysosomes, vesicles, endoplasmic reticulum, microtubules, flagella and so on. Common inclusion bodies are glycogen, crystals, liposomes and so on.
The vegetative hyphae of fungi often undergo a variety of metamorphosis, so as to obtain nutrients more effectively and meet the needs of growth and development. Common metamorphic hyphae include haustorium, pressure cells, bacterial nets and bacterial sheaths. The former two are mostly formed in plant parasitic fungi, while the latter two are mostly formed in fungi that prey on nematodes. When the mycelium of some fungi develops to a certain stage, it becomes loose or closely interwoven tissue, which is different from the loose mycelium that usually constitutes the thallus and is called dense silk tissue. This tissue constitutes different types of structures of many fungi, such as funiculus, sclerotia and matrix.
The organic matter needed by fungi in life depends on other organisms in nature. Fungi that absorb nutrients from dead organisms are called saprophytes. Fungi that can invade living organisms but cannot survive on dead organisms are called absolute parasites. Parasitism and saprophy are not absolute. Under certain conditions, some fungi can invade living organisms and feed on dead organisms. This fungus is called facultative parasite or facultative saprophyte. Many fungi, on the one hand, absorb nutrients from other organisms, on the other hand, provide nutrients or benefits for the same organism. This is a * * * phenomenon, and fungi related to * * * are called * * * bacteria.
The propagation modes of fungi include asexual reproduction, sexual reproduction and quasi-sexual reproduction. Asexual reproduction refers to the generation of new individuals without the combination of bisexual cells. The propagation methods include: ① somatic cell (mycelium) rupture; ② Somatic cells divide into daughter cells; ③ Germination of somatic cells or spores; ④ The production of various asexual spores (such as zoospores [/url, sporangium spores, conidia, chlamydospores, etc.). ), each spore can germinate the germinating tube and then form mycelium. Asexual reproduction plays an important role in the propagation and spread of fungi. Sexual reproduction includes swimming gamete mating, gametophyte contact mating, gametophyte mating, spore mating and somatic cell mating. Some fungi perform nuclear matching immediately after quality matching. Other fungi don't match nuclei immediately, so they have a binucleate phase, that is, there are two unbound nuclei in each cell. When cells grow or divide, they divide at the same time, which is a unique phenomenon of fungi. The two nuclei will not cooperate until very late. After nuclear matching, meiosis will occur sooner or later, which will reduce the number of chromosomes to haploid again. The sexual reproduction of fungi eventually forms various sexual spores, such as dormant sporangium, oospore, zygospore, ascospore and basidiospore.
In 1952, Americans C. Pontecorvo and Roper discovered the mechanism leading to gene recombination in filamentous fungi. In this mechanism, gene recombination does not depend on meiosis of sexual reproduction, but on mitosis of quasi-sexual reproduction. The process of quasi-sexual reproduction can be summarized into several stages: cytoplasmic matching, nuclear matching and haploid. Quasi-sexual reproduction plays a certain role in evolution. Sexual reproduction and quasi-sexual reproduction are not mutually exclusive. Some fungi, such as Aspergillus nidulans, have both sexual reproduction and quasi-sexual reproduction. Some live in water, others live on land; Some grow in the tropics, and some grow in the cold zone; Some can grow all year round, and some only grow in a certain season; Some are parasitic on other creatures, some are born with other creatures, and some can only grow on the decaying remains of other creatures. Each fungus has special requirements on nutrition, temperature, humidity, pH value, oxygen and light.
There are two main schools of thought about the origin and evolution of fungi. One school thinks that fungi evolved from algae. Due to the loss of pigment, these algae changed from autotrophic to heterotrophic, and the physiological changes caused morphological changes. Another school thinks that except oomycetes from algae, other fungi come from primitive flagellates.
Fungi is a rich natural resource. People and animals consume a lot of fungi and fruiting bodies every year; Fungi are also important medicinal materials. Some metabolites of fungi are widely used in industry, such as ethanol, citric acid, glycerol, enzyme preparations, sterols, fats, plastics, growth promoters, vitamins and so on. And these things can be produced on a large scale. In agriculture, forestry and animal husbandry, fungi have both harmful and beneficial aspects. Fungi can cause a variety of plant diseases and cause huge economic losses. For example, in 1845, 5/6 of potatoes were destroyed in Europe due to the epidemic of potato late blight, and in China, due to 1950 wheat rust and 1974 rice blast, the output of wheat and rice decreased by 6 billion kilograms each. However, mycorrhiza can provide essential nutrients for many woody and herbaceous plants. During the decomposition of fungi, it recovered many important chemical elements. Fungi directly or indirectly affect the material circulation and energy conversion of the earth's biosphere.
yeast
Unicellular fungi. Generally oval, round, cylindrical or lemon-shaped. Colony morphology is similar to that of bacteria, but it is bigger and thicker, milky white or red, and its surface is wet and sticky, so it is easy to be irritated. Reproductive modes are divided into asexual reproduction and sexual reproduction. There are two kinds of asexual reproduction: budding and fission. When the environmental conditions are suitable and Candida lipolytica grows and reproduces rapidly, the daughter cells formed by budding have not been separated from the mother cells, and new buds have grown to form a series of cells similar to pseudofilaments, so it is called Candida. Sexual reproduction produces ascospores. Yeast is widely distributed, more on the surface of vegetables and fruits with high sugar content, and less in air and soil.
Yeast plays an important role in brewing, food and medicine industries. As early as 4,000 years ago in Shang Dynasty, China used yeast to make wine. Yeast is rich in vitamins and protein, which can be used in food, medicine and feed. It is also the raw material for extracting various biochemical products such as nucleotide, coenzyme A, cytochrome C, glutathione and adenosine triphosphate, and can also be used for producing vitamins, amino acids and organic acids. Candida lipolytica for petroleum dewaxing. A few kinds of yeasts will lead to instrument corruption, such as honey yeast, which will spoil honey and jam. Hansen yeast often pollutes alcoholic beverages and is also a harmful fungus in alcohol fermentation industry. Candida albicans can cause many diseases such as skin, mucosa, respiratory tract, digestive tract and urinary system.
Yeast is a fungal organism, and its classification is chaotic, mainly in different forms. According to J. Lodder's yeast taxonomy, Saccha romycetaceae, which can form ascospores, is also called real yeast, such as S. Debaryomyces. There are also some yeasts that do not form spores, belonging to Hemiptera, Cladosporium, Cryptococcidae, such as Candida.
Some people may not be familiar with the name yeast, but in fact people enjoy the benefits of yeast almost every day. The bread and steamed bread we eat every day are all made by yeast. The beer we drink is also inseparable from the contribution of yeast. Yeast is a microorganism used earlier in human practice. Working people in ancient China used yeast to make wine. Yeast cells are rich in protein and vitamins, so they can also be made into advanced nutrients to be added to food or used as advanced feed for raising animals.
Yeast is widely distributed in nature, especially in acidic and sugary environments. For example, it is most common on the surface of fruits, vegetables and nectar and in orchard soil.
Yeast generally has high nutritional value, especially contains more protein, a variety of B vitamins, nucleic acids and minerals, and can also produce some health-care functional active substances. Vitamin B group can control the metabolic function of human body and maintain normal nerve function. Vitamin B2 and vitamin B6 are very important vitamins for the skin. Vitamin B 12 can prevent anemia and promote the synthesis of vitamins in the intestine, so it can enhance the physical strength of people with weak intestine or liver function. In addition, it has been reported that yeast SH2 fermentation culture was analyzed by gel chromatography column G-75 and separated by protein elution at the wavelength of 280nm, and it was found that two protein elution peaks enhanced the titer of interferon, which further proved that it was a nuclear protein (protein-sugar ratio was 3: 1), but it was not DNA or RNA. If this experimental information is further confirmed, it can be explained that yeast fermentation culture can enhance the titer of interferon, thus enhancing the immune function of the body.
Recently, some health foods and special nutritional foods with yeast as carrier and some micronutrients have appeared in China, such as iron-rich yeast, selenium-rich yeast and zinc-rich yeast. That is to say, in the culture medium used for yeast production, the concentrations of iron, zinc and selenium increase, so that yeast contains more of these substances for human consumption. Yeast rich in certain nutrients can also be mixed into livestock feed, and milk, eggs and meat rich in certain nutrients can be produced after further transformation. At present, the functional substance of this food transfer is limited to nutritional substances, and whether it can be extended to non-nutritional functional substances is of course an issue of interest to people.
Yeast can reproduce in many ways. Some people call asexual yeast "false yeast" and sexually propagated yeast "true yeast".
Asexual propagation of yeast
Bud propagation: The most common asexual propagation mode of yeast is bud propagation. Buds occur at predetermined points on the cell wall, which are called bud marks. Each yeast cell has one or more bud marks. Mature yeast cells sprout buds, and the nucleus of the mother cell splits into two sub-nuclei, one of which enters the bud with the cytoplasm of the mother cell, and when the bud approaches the size of the mother cell, it falls off from the mother cell and becomes a new individual, and so on. If the yeast grows vigorously, new buds can grow on the buds before they fall off from the mother cells, and finally form pseudohyphae.
Schizogenesis is a way of asexual reproduction of a few yeasts, which is similar to the fission of bacteria. The process is that the cell is elongated, the nucleus is split in two, and a diaphragm appears in the center of the cell, which divides the cell into two daughter cells with monocytes.
Sexual reproduction of yeast
Yeast reproduces sexually by forming ascospores and ascospores. Two adjacent yeast cells each extend a tubular protrusion, and then contact and fuse with each other to form a channel. Two nuclei combine in this channel to form a diploid nucleus, and then undergo meiosis to form four or eight nuclei. Each nucleolus and its surrounding protoplasm form spores, which are ascospores, and the cells that form ascospores are called ascospores.
lactobacillus
Refers to a class of gram-positive bacteria without spores, and the main product of fermented sugar is lactic acid. Most people don't exercise, and a few exercise with their hair. Bacteria are often arranged in chains. Homotypic lactic acid fermentation is called lactic acid fermentation, and heterotypic lactic acid fermentation is called lactic acid fermentation. Besides lactic acid, there are more substances such as acetic acid, ethanol and CO2. There are microaerobic bacteria and obligate anaerobic bacteria. According to spherical or rod-shaped cells, they can be divided into two categories, namely Streptococcus and Lactobacillus. Lactococcus family, the cells are spherical, usually in pairs or chains, with small colonies and slow growth on solid medium. Most of them are isoenzymes, such as streptococcus, which is an important flora closely related to human beings, and some bacteria are pathogenic bacteria of human beings and warm-blooded animals; Some are normal flora in human oral cavity and intestine; Some bacteria are commonly used in dairy products and plant fermented foods, and also in food industry, such as Streptococcus lactis. A few strains are heterotypic fermentation, such as Leuconostoc mesenteroides, which is an important strain for producing dextran (that is, plasma substitute) in pharmaceutical industry, but it is also a harmful bacteria in sugar industry, which often makes sugar juice sticky and cannot be processed. Lactobacillus family, rod-shaped, single-chain or chain-shaped, sometimes filamentous, producing false branches. According to the different products after using glucose, it can be divided into homotype fermentation group and heterotype fermentation group. Most kinds of lactose can be fermented without lactic acid, and the pH value can be reduced below 6.0 after fermentation. Lactobacillus is the most important species in this family, most of which are commonly used in industry, especially in food industry. It exists in dairy products, fermented plant foods such as pickles, sauerkraut, silage and human intestines, especially in infants. Thermofermentative bacteria are usually used in the industrial production of lactic acid. For example, the optimum growth temperature of Lactobacillus delbrueckii is 45℃, which is widely used in lactic acid manufacturing and calcium lactate manufacturing industries.
actinomyces
Actinomycetes are a group of prokaryotes. Most of them have developed branched hyphae. The mycelium is slender, and its width is close to that of rod-shaped bacteria, about 0.5 ~ 1 micron. It can be divided into: vegetative hyphae, also known as matrix hyphae, whose main function is to absorb nutrients, and some can produce different pigments, which is an important basis for strain identification; Aerial hyphae, superimposed on vegetative hyphae, are also called secondary hyphae. Spore filaments that can produce spores are differentiated from aerial hyphae, and the shape and arrangement of spore filaments of different species are also different. Clusters of conidia are produced on mature sporangia. The surface structure, shape and color of spores are relatively stable under certain conditions, which is an important basis for identifying strains. Through asexual spores and bacterial division and reproduction. Most of them are heterotrophic aerobic bacteria. Some species can decompose complex organic matter such as cellulose at high temperature. It is widely distributed in nature, most of which are saprophytic and a few are parasitic. It produces a variety of antibiotics. It is estimated that 2/3 of the more than 4,000 antibiotics found are produced by actinomycetes. Has a close relationship with human beings. The important genera are Streptomyces, Micromonospora and Nocardia.
Actinomycetes are more complex than bacteria, but they still belong to single cells. Under the microscope, actinomycetes are branched and filamentous. We call these filamentous structures hyphae, and the diameter of hyphae is similar to that of bacteria, less than 1 micron. The structure of mycelium cells is basically the same as that of bacteria.
According to the different forms and functions of hyphae, actinomycetes hyphae can be divided into three types: matrix hyphae, aerial hyphae and sporophytes. Streptomyces is a group with the most species, the widest distribution and the most typical morphological characteristics among actinomycetes.
Substrate mycelium crawls on the surface of nutrient substrate or extends into the substrate. Like the roots of plants, they have the function of absorbing water and nutrients. Some can also produce all kinds of pigments and dye the culture medium into all kinds of beautiful colors. Most kinds of actinomycetes, such as Streptomyces and micromonospora, have no membrane and will not break. However, there is a kind of actinomycetes, such as Nocardia actinomycetes, whose substrate mycelium grows for a certain period of time and breaks into spheres or rods.
Aerial hyphae are hyphae that grow from the culture medium and extend into the space of matrix hyphae. When observed under a microscope, aerial hyphae are usually darker and thicker than matrix hyphae. Matrix mycelium is light and shiny. Some actinomycetes have developed aerial hyphae, some are sparse, and some species have no aerial hyphae.
Sporothrix is a spore-producing mycelium which is differentiated from aerial mycelium after it has developed to a certain extent. Spore filaments of actinomycetes are various in shape, including straight, wavy, hooked, spiral, primary whorl and secondary whorl, which is one of the important signs of actinomycetes colonization.
Spore filaments differentiate into conidia at a certain stage of development. Under the optical microscope, spores are round, oval, rod-shaped, cylindrical, melon-seed-shaped, spindle-shaped and half-moon-shaped, and the colors of spores are very rich. The ornamentation on the spore surface varies from species to species and can be clearly seen under the electron microscope. Some are smooth, some are folded, with warts, thorns, hairs or scales, and the thorns are divided into thickness, size, length and density.
Actinomycetes cysts are characterized by the formation of typical cysts, and the location of cysts varies from species to species. Some cysts grow on the air silk, while others grow on the bottom silk. The formation of sporangium can be divided into two forms: the sporangium of some genera is formed by the winding of sporophyte; The sporangium of some genera gradually expands from sporangium group. There are walls around the cyst, and those without walls are generally called pseudocysts. Cysts are round, rod-shaped, finger-shaped, bottle-shaped or irregular. Protoplasts in sporangium differentiate into sporangium spores, and those with flagella swim in water, such as actinomycetes; Not swimming without flagella, such as Alternaria.
Streptomyces is a higher actinomycete. There are well-developed branched hyphae without septa, which differentiate into vegetative hyphae, aerial hyphae and 65 sporophytes. Spore filaments re-form conidia. The shape and color of sporangium and spore vary from species to species, which is one of the main distinguishing characteristics of species. It is reported that there are more than 1000 species, mainly distributed in soil. It is known that 90% of antibiotics produced by actinomycetes are produced by this genus. The Institute of Microbiology of China Academy of Sciences divided the genus into 14 species groups according to the characteristics of the color of aerial mycelium (spore pile), the color of matrix mycelium, soluble pigment, the shape of sporophyte, the shape and surface structure of spores, and each species group included many different species, which served as the basis for identifying Streptomyces and searching for new antibiotic-producing bacteria. The main representative is streptomyces griseus, which produces streptomycin.
Micromonospora mycelium is slender, with a diameter of 0.3 ~ 0.6 micron, branched and unbroken. Only vegetative hyphae (matrix hyphae) are formed, which go deep into the culture medium and do not form aerial hyphae. Spores are solitary, sessile, or attached to long or short spore stalks, which are usually branched into clusters. Colonies are small, generally 2 ~ 3 microns in diameter, usually orange or red, with dark brown, black and blue edges and covered with a layer of powdery spores. Generally it is aerobic saprophyte. Most of them are distributed in soil or lake bottom soil, and there are also a lot of compost and manure. There are about 30 kinds. It is a genus that produces more antibiotics. Some species also accumulate vitamin B 12. Important representatives are micromonospora purpurea and micromonospora crimson, which produce gentamicin.
Ncardia is a protoactinomycete. Typical branched mycelium is formed on the culture medium, and most of them have no aerial mycelium. Culture/kloc-for 0/5 to 4 hours, no hyphae produced a diaphragm, and the diaphragm suddenly broke and grew into a rod, ring or fork-shaped rod. Each stem has at least one nucleus, so it can replicate and form a new multinucleated mycelium. Colonies are generally smaller than Streptomyces colonies, with wrinkles on the surface, dense and dry, and easy to break when touched. Most of them are aerobic saprophytes, and a few are anaerobic parasites. More than 100 species have been reported, mainly distributed in soil. Many kinds can produce antibiotics, such as rifamycin, and some are used in petroleum dewaxing, hydrocarbon fermentation and sewage treatment.
Nonspecific immunity is also called innate immunity and species immunity. It is a series of defense mechanisms gradually established by organisms in the process of long-term systematic development and evolution, in constant contact and action with pathogenic microorganisms and other antigenic foreign bodies invaded by the outside world. Its characteristics are: (1) It is congenital and determined by genetic factors, so it has relative stability. (2) wide range of action, no selectivity, and certain immunity to various pathogenic microorganisms and antigenic foreign bodies. (3) There are species differences. That is, people and animals can have natural insensitivity to some pathogenic microorganisms and their products. Such as: human to chicken cholera bacteria; Chickens are not sensitive to anthrax. (4) In anti-infective immunity, it appears early, acts quickly, and the reaction intensity is relatively stable, which does not change with the number of times of contact with an antigen. Nonspecific immunity consists of many components, including barrier structure, phagocyte system, complement system and other antibacterial substances in body fluids. Nonspecific immunity is the basis of specific immunity and the basic condition of artificial immunity. In anti-infection immunity, firstly, nonspecific immunity plays a role; With the formation of specific immunity, the two cooperate with each other and expand the immune function. Therefore, enhancing non-specific immunity is an important aspect of improving immunity.
A group of prokaryotes. Most of them have developed branched hyphae. The mycelium is slender, and its width is close to that of rod-shaped bacteria, about 0.5 ~ 1 micron. It can be divided into: vegetative mycelium, also known as matrix mycelium, whose main function is to absorb nutrients, and some can produce different pigments, which is an important basis for strain identification; Aerial hyphae, superimposed on vegetative hyphae, are also called secondary hyphae. Spore filaments that can produce spores are differentiated from aerial hyphae, and the shape and arrangement of spore filaments of different species are also different. Clusters of conidia are produced on mature sporangia. The surface structure, shape and color of spores are relatively stable under certain conditions, which is an important basis for identifying strains. Through asexual spores and bacterial division and reproduction. Most of them are heterotrophic aerobic bacteria. Some species can decompose complex organic matter such as cellulose at high temperature. It is widely distributed in nature, most of which are saprophytic and a few are parasitic. It produces a variety of antibiotics. It is estimated that 2/3 of the more than 4,000 antibiotics found are produced by actinomycetes. Has a close relationship with human beings. The important genera are Streptomyces, Micromonospora and Nocardia.
Streptomyces is a higher actinomycete. There are well-developed branched hyphae without septa, which differentiate into vegetative hyphae, aerial hyphae and 65 sporophytes. Spore filaments re-form conidia. The shape and color of sporangium and spore vary from species to species, which is one of the main distinguishing characteristics of species. It is reported that there are more than 1000 species, mainly distributed in soil. It is known that 90% of antibiotics produced by actinomycetes are produced by this genus. The Institute of Microbiology of China Academy of Sciences divided the genus into 14 species groups according to the characteristics of the color of aerial mycelium (spore pile), the color of matrix mycelium, soluble pigment, the shape of sporophyte, the shape and surface structure of spores, and each species group included many different species, which served as the basis for identifying Streptomyces and searching for new antibiotic-producing bacteria. The main representative is streptomyces griseus, which produces streptomycin.
Micromonospora mycelium is slender, with a diameter of 0.3 ~ 0.6 micron, branched and unbroken. Only vegetative hyphae (matrix hyphae) are formed, which go deep into the culture medium and do not form aerial hyphae. Spores are solitary, sessile, or attached to long or short spore stalks, which are usually branched into clusters. Colonies are small, generally 2 ~ 3 microns in diameter, usually orange or red, with dark brown, black and blue edges and covered with a layer of powdery spores. Generally it is aerobic saprophyte. Most of them are distributed in soil or lake bottom soil, and there are also a lot of compost and manure. There are about 30 kinds. It is a genus that produces more antibiotics. Some species also accumulate vitamin B 12. Important representatives are micromonospora purpurea and micromonospora crimson, which produce gentamicin.
Ncardia is a protoactinomycete. Typical branched mycelium is formed on the culture medium, and most of them have no aerial mycelium. Culture/kloc-for 0/5 to 4 hours, no hyphae produced a diaphragm, and the diaphragm suddenly broke and grew into a rod, ring or fork-shaped rod. Each stem has at least one nucleus, so it can replicate and form a new multinucleated mycelium. Colonies are generally smaller than Streptomyces colonies, with wrinkles on the surface, dense and dry, and easy to break when touched. Most of them are aerobic saprophytes, and a few are anaerobic parasites. More than 100 species have been reported, mainly distributed in soil. Many kinds can produce antibiotics, such as rifamycin, and some are used in petroleum dewaxing, hydrocarbon fermentation and sewage treatment.
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Most actinomycetes are composed of multicellular branched hyphae. Most hyphae have no septa, and the thickness is similar to that of coryneform bacteria, with a diameter of about 65438 0 microns. The cell has nucleoplasm but no eukaryote, and the cell wall contains muramic acid and diaminopimelic acid, but does not contain chitin and cellulose.
The hyphae of actinomycetes can be divided into three parts according to their shapes and functions: matrix hyphae, aerial hyphae and sporophytes. Matrix hyphae, also known as vegetative hyphae, grow in culture medium, whose main function is to absorb nutrients, with a diameter of 0.2 ~ 0.8 microns. The aerial mycelium is formed by the extension of the culture medium growing in the substrate mycelium to the outside of the space, which is thicker than that in the substrate mycelium, with a diameter of 1 ~ 1.4 micron, a straight or arc shape, and some of them produce pigments. Actinomycetes grow to a certain stage and differentiate into spores on aerial hyphae, which are called sporophytes. The shape of spore silk and its arrangement on aerial hyphae vary from species to species, some are straight, some are curved or spiral; Some alternate, some alternate or cluster.