Bacteria (English: germs; ; Scientific name: bacteria is a kind of prokaryotic organism in a broad sense, which refers to a large class of primitive single-celled organisms, wrapped in the nuclear membrane of the nucleus, and only the bare DNA is called the nuclear region (or pseudonucleus), including eubacteria and archaea. Except for a few archaea, most prokaryotes are true bacteria. It can be roughly divided into six kinds, namely bacteria (in a narrow sense), actinomycetes, spirochetes, mycoplasma, rickettsia and chlamydia. What people usually call bacteria in a narrow sense is a kind of prokaryote, which is a kind of prokaryote with short body and simple structure, and often reproduces in a binary way. It is the most widely distributed creature with the largest number of individuals in nature, and it is the main participant in the natural material cycle. Bacteria are mainly composed of cell wall, cell membrane, cytoplasm and nucleosome, and some bacteria also have special structures such as capsule, flagella and fimbriae. Most bacteria are between 0.5 and 5 μ m in diameter, and can be divided into three categories according to their shapes, namely cocci, bacilli and spirillus (including vibrio, spirillus and spirillus). There is also a classification based on the life style of bacteria, which is divided into autotrophic bacteria and heterotrophic bacteria, among which heterotrophic bacteria include saprophytic bacteria and parasitic bacteria. 2009-10-211:37 With the gradual improvement of living standards, people's awareness of health and disease prevention is also constantly strengthening. Most people know that bacteria can cause diseases, and they are used to using "bacteria" or "bacteria" to describe a dirty environment or object. So, what about fungi? Is it a kind of bacteria? It is true that fungi are small and can make people sick, but they are essentially different from bacteria.

As we know, plants and animals are made up of cells with nuclei. Among microorganisms, only fungi have real nuclei and complete organelles, so they are also called eukaryotic microorganisms. Bacteria only have the original nuclear structure, no seed membrane and nucleoli, and few organelles, belonging to prokaryotic cell microorganisms; The virus has no cell structure and belongs to protozoa.

Fungi are widely distributed in nature, with more than100000 species, of which only a small part, about 300 species, can cause human or animal infections. Many fungi are beneficial to human beings, such as flour fermentation, soy sauce, vinegar, wine and moldy tofu. Many enzyme preparations in industry and feed fermentation in agriculture are inseparable from fungi. Many fungi can also be eaten, such as mushrooms, tremella, mushrooms, fungus and so on. Fungi are also valuable resources in medicine, some of which can be used to produce antibiotics, vitamins and enzymes; Some of them can be used as medicine to treat diseases, such as puffball, poria cocos and cordyceps sinensis.

Fungi can also cause many diseases of animals, plants and human beings. There are three main kinds of human beings: ① fungal infection; ② Allergic diseases; ③ Toxic diseases.

mould

Also known as "filamentous bacteria". This is a fungus. The body is filamentous and tufted, and can produce various forms of spores. More rotten. There are many kinds, such as Rhizopus, Mucor, Aspergillus and Penicillium. Mold can be used to produce industrial raw materials (citric acid, methylene succinic acid, etc. ), food processing (brewing soy sauce, etc. ), antibiotics (such as penicillin and griseofulvin) and pesticides (such as "920" and Beauveria bassiana). However, it will also lead to mildew and deterioration of industrial raw materials and products, as well as agricultural and forestry products. Another small number of molds can cause diseases of people, animals and plants, such as tinea capitis, tinea pedis and sweet potato rot.

yeast

This is a fungus. The body is round, oval or ovoid, and there are nuclei, vacuoles and granular substances inside. Usually propagated by budding; Some can be split in half; Some species can produce ascospores. Widely distributed in nature, especially in grapes and other fruits and vegetables. It is an important starter, which can decompose carbohydrates to produce alcohol and carbon dioxide. Bread yeast, feed yeast, alcohol yeast and wine yeast are commonly used in production. Some can synthesize medical cellulose, and some can be used for petroleum fermentation.

brewer's yeast

It belongs to the genus Saccharomyces. Cells are round, oval or oval. Bud grafting can form ascospores. In the fermentation industry, it can be used to produce alcohol or medicinal yeast, and products such as clots, ergosterol, lecithin, coenzyme A and cytochrome C can be extracted through comprehensive utilization of bacteria.

Monascuspurpureus belongs to Ascomycetes, Aspergillus. The mycelium is purplish red. In the process of asexual reproduction, one or a small cluster of spherical or pear-shaped meristems is formed at the top of the mycelium branches. During sexual reproduction, spherical and orange-red fruit is produced, and an ascospore containing 8 ascospores is endogenous. Monascus can make Monascus, brew red lactobacillus and produce glucoamylase.

mycotoruloides

Yeast that can form pseudohyphae without producing ascospores. Many candida species can use n-alkanes as carbon sources for petroleum fermentation and dewaxing, and produce valuable products. Among them, Candida lipolytica or Candida tropicalis is a Candida species with strong ability to oxidize n-alkanes. Some species can be used as feed yeast; Individual species can cause human or animal diseases.

Candida albicans

Or Candida albicans. An oval candida, which can germinate and reproduce. It usually exists in the mouth, intestines and upper respiratory tract of normal people and can cause oral diseases, such as thrush or other diseases.

Aspergillus flavus

A little knowledge of fungi, Aspergillus flavus common saprophytic fungi. More common in moldy grains, grain products or other moldy organic matter. The colony grows rapidly, with loose structure, yellow-green surface and colorless or slightly brown back. The thallus is composed of many complicated branched hyphae. Vegetative hyphae are separated; Some aerial hyphae form a long and rough conidiophore, and a bottle-shaped or nearly spherical apical sac is produced at the top of the stem. There are many peduncles (usually double-layered) on the surface of the capsule, and spherical conidia with rough surface are formed on the peduncles. Conidiophore, apical sac, peduncle and conidia are in the ear of synthetic spores. It can be used to produce amylase, protease and phosphodiesterase, and it is also a common strain in wine-making industry. In recent years, it has been found that some of these strains can produce aflatoxin, causing cancer in human and livestock liver. As early as the 6th century AD, Qi Shu Yao Min recorded that soy sauce was made from yellow clothes and yellow steamed wheat koji. These two kinds of yellow wheat starter are mainly composed of a large number of spores produced by Aspergillus flavus, protease and amylase.

Geotrichum candidum

This is a fungus. Colony plane diffusion, tissue light and soft, milky white. When the mycelium grows to a certain stage, it will break into cylindrical fruit. The optimum temperature for cell growth is 28℃. Common in milk and various dairy products (such as yogurt and cheese); Geotrichum candidum is usually found in pickles and soy sauce. Can be used for making picric acid and yeast tablets.

Antibiotic bacteria

Also known as "antagonistic (antagonistic) antibacterial". It can inhibit the growth and development of other microorganisms and even kill some microorganisms of other microorganisms. Some of them can produce antibiotics, mainly actinomycetes and some fungi and bacteria. Such as streptomycin produced by Streptomyces, penicillin produced by Penicillium, polymyxin produced by Myxomycetes, etc.

pseudohypha

Some yeasts, such as Candida, germinate and reproduce, and their daughter cells form long chains and have branches, which are called pseudohyphae. The intercellular junction is narrow, such as lotus root node, and there is generally no diaphragm.

antibiotic

Also known as "antibiotics". Mainly refers to the chemical substances produced by microorganisms that can inhibit or kill other microorganisms, such as penicillin, streptomycin, chlortetracycline, kasugamycin, gentamicin and so on. Antibiotics can also be extracted from some higher plants and animal tissues. Some antibiotics, such as chloramphenicol and cycloserine, are mainly produced by chemical synthesis at present. By changing the chemical structure of antibiotics, new antibiotics with better performance can be obtained, such as semi-synthetic neopenicillin. In medicine, antibiotics are widely used to treat many microbial infectious diseases and some cancers. In animal husbandry and veterinary medicine, it is not only used to prevent some infectious diseases, but also used for some antibiotics to promote the growth of poultry and livestock. In agriculture and forestry, it can be used to control microbial diseases of plants. In the food industry, it can be used as a preservative for some foods.

Pathogenic bacteria

Fungi (fungi) are eukaryotic microorganisms, which belong to phycomycetes in biological classification. They are widely distributed in nature, and most of them are beneficial to people, such as wine making, sauce making, fermented feed, fattening farmland, making antibiotics, planting mushrooms, food processing and providing Chinese herbal medicine sources (such as Ganoderma lucidum, Poria cocos and Cordyceps sinensis). ), which are all products of fungi, are prepared by themselves or by fungi. Fungi that cause diseases to human beings can be divided into superficial fungi and deep fungi. The former is chronic and difficult to treat, but it has little effect on the body. The latter can invade the internal organs of the whole body and cause death in severe cases. In addition, some fungi are parasitic in grain, feed and food, which will produce toxins and cause toxic mycosis.

Bacteria are unicellular organisms, belonging to prokaryotic cells, with small volume and simple structure. No nucleus, nucleoli and nuclear membrane are formed, and there are no other organelles except ribosomes. It has a relatively stable shape and structure under suitable conditions. Generally, the morphological characteristics of various bacteria can be identified by observing them with an optical microscope, but the internal ultrastructure can only be seen with an electron microscope. The morphology of bacteria is of great theoretical and practical significance to the diagnosis and prevention of diseases and the study of bacteria.

Bacteria are generally spherical, rod-shaped or spiral prokaryotes, which usually reproduce in binary division. Bacteria are very small. Generally, the diameter of cocci is 0.5 ~ 1.0 micron, the width of bacilli is 1 micron, and the length is 2 microns. Bacteria are widely distributed in nature, which exists in soil, water, air, animal and plant surfaces and digestive tract. Soil is the main distribution place of bacteria, and each gram of dry soil contains about 10 to 10 times of bacteria. Most bacteria are heterotrophic, and a few are autotrophic, including chemoautotrophic and photoautotrophic. Most heterotrophic bacteria are saprophytic and a few are parasitic.