morphology
In different bacteria, the position of the spores is different, some in the middle, some in the bias, some at the top. The spores are generally circular, elliptical, and cylindrical. In some bacteria, the diameter of the spores is smaller than the diameter of the bacteria, which is called Bacillus, which is a good oxygen bacteria; in the other bacteria, the diameter of the spores is greater than the diameter of the bacteria, so that the entire bacteria is a shuttle or a drum shape. These bacteria are called closses of Bacillus, which is anaerobic bacteria, spores of clossed Bacillus, in the middle of the bacterium. The spores of Trepid Bacillus are located at one end of the bacterium, so that the bacteria is drummed. All bacteria of Bacillus and anaerobic clostridium have spores. In the Susperans and Spirals, there is only a small number of spores, sporosarcina is baked in spores. There is only a spore spore spore.
formation of
spores is an extremely complex process, including variations such as morphological structures, chemical components. . Optical microscope and electron microscope observation research results showed that the formation of spores mainly experienced the following stages: 1 nuclear substance fusion into shaft cylinders (rod). 2 In the center or one end of the cell, the cell membrane is inserted into the diaphragm to enclose the nuclear material, producing a small cell. 3 Small cells were surrounded by the original cell membrane, produced primary spores. The primary spore is essentially a protoplast surrounded by two concentric membranes. Unsubstated live bacteria were observed under optical microscope, and it was possible to see that the probiotic was clear and the other parts of the bacteria were significantly different. 4 The prigrant is surrounded by a plurality of membranes, such as cortex, spore coat, etc., and finally a mature spore, released due to the collating of the cell wall.
During the chemical composition during spore formation, there is a large change in chemical components. Birth of the buddy cells absorb calcium ions and synthesize a pyridine dicarboxylic acid in nutrient cells. In mature spores, the sporelactomers contain extremely high pyridine dicarboxylic acid calcium, and have such a substance in the newly synthetic, external (cortex and spore coat, sometimes with spores). The walls of the spores contain a particular peptidin, all of which are basically the same, but the cell wall peptides with nutrient cells are different. At the same time, spores also contain some special proteins.
Features
Because the spores are different from nutrient cells on the structure and chemical composition, the spores have a number different from the characteristics of nutrient cells. The main characteristics of spores are strong resistance, high temperatures, ultraviolet, dry, ionizing radiation, and many-toxic chemicals have strong resistance. At the same time, there is also a strong refractive property in spores. When the staining sporeral smear is observed under the microscope, the spores can be easily distinguished, because the nutrient cells have colors, while the spores are anti-dye and high refractive property, exhibiting transparent and colorless appearance . Studies have shown that the resistance of bud binder defective environmental factors is mainly due to low water content (40%). It contains heat-resistant small alkases, rich in a large amount of special pyridine dicarboxylate and protein with disulfide bonds, and spore walls having a multi-layer thick and dense. Freely existing spores have no obvious metabolism, only maintained potential germination, called hidden life. Once the environmental conditions are suitable, spores can germinate into a nutrient cell.
The characteristics of bacteria spores Overview
The strongest life in the entire biological industry can eliminate spores to measure the most important indicators of various disinfection methods.
Spore is a bacteria sleeping body, which can be re-converted into nutrient cells under suitable conditions;
Bacterial deposits are used to use their spores. Most bacteria produced by spores, there are some sputum.
Bithosporic, morphology, size and life position are important indicators in bacteria classification and identification.
spores have a large difference in chemical composition compared to nutrient cells, and it is easy to observe under optical microscope. (Direct observation of phase difference microscopy; spore staining)
"Environmental Engineering Microbiology" One Book: Description of Its Characteristics:
The moisture content of spores is low, 38% ~ 40%.
⒉ spores thickness and dense, divided into three layers: outer layer is a spore housing for protein properties. The medium layer is a skin layer, consisting of peptidin, containing a large amount of 2,6-pyridine dicarboxylic acid. The inner layer is a spore wall, composed of peptidin, surrounding spore cytoplasmic and nucleus. The spore wall is changed to the cell wall of the spore wall after spores.
The 2,6-pyridine dicarboxylic acid in the spores is high, which is 5% to 15% of the binder weight. Pyridinicarboxylic acid
Existing in the form of calcium salt, high calcium content. 2,6-pyridine dicarboxylic acid was found in the cells and non-spore bacteria. During spore formation, 2,6-pyridine dicarboxylic acid is synthesized, and the spores have heat resistance. When spores forming nutrient cells, the 2,6-pyridine dicarboxylic acid disappears, and heat resistance is lost.
⒋ contain heat resistance.
Bithdia is the above four characteristics, it is a spore for adverse environments such as high temperature, low temperature, dry, light and chemical drugs have strong resistance. Bacterial nutrient cells die at 70 to 80 degrees Celsius, while spores can survive in 120 to 140 degrees Celsius, nutrient cells will die quickly in 5% phenol solutions, spores can survive 15 days, spores Most enzymes are inactive, metabolic vitality is extremely low, so spores are dormant in a bad environment.
spores are not easy to color, but can be stained with peacock green.
Heating mechanism
osmotic regulatory cortex expansion: spybrosis has a high ionic intensity of the permeability of multi-valent cations and moisture, producing extremely high osmotic pressure The moisture of the spores, resulting in sufficient expansion of the cortex. The cytoplasm of the core portion becomes high, and therefore, with extremely strong heat resistance.
germination
The spores formed by the just formed are always in a sleep state. Heat treatment (such as at 65 ° C for dozens of minutes) can activate spores accelerate. Low temperature storage is also activated, just slow.
Specializing in binder, the inflation effect is first, and the refractive property and loss of resistance are lost, then the respiration begins, showing metabolic activity, and 30% of sporcosis (dry weight) becomes soluble. Out, the nutrient cell wall is rapidly synthesized, and finally, the newly formed nutrient cells are gentle from the spore clothes. Germination usually has three ways: the equatorial discharge, the end is discharged, oblique.
Essentially
Bucomy bacteria is equivalent to transverse, and one parent cell produces two subcamr. In the process of splitting, there is no production of spores; while giant, when a spore is produced, a bacterium only produces a spore, and there is no quantity increase.
Generally, the spores are formed at the late growth and nutrient lack of nutrients, and thus is a product that is adapted to the bad environment. But in fact, it may be not entirely. Some people have tracked observations when cultured by Bacillus Bacillus. As a result, there was found that there were spores after inoculation of 4 hours. Every 4 hours later, the number of spores increased proportion. By 24 hours, a spore was produced by about half; 48 hours, all become spores. This situation suggests that nutrient cell steering germination has a certain probability in this case. The beginning of spores does not have to wait until the late growth, it is not necessary to wait until the growth is completely stopped.
It is a positive generation of a new organ. The root cause of determining the formation of spores is in the bacterial interior, and there is a gene that controls spores formed on the bacterial chromosome. Bacteria In nutrient growth, these genes are often not expressed, they may be controlled by a repression system, and once this suppression is eliminated, spores can be caused.
Sometimes people collect spores, flavors, etc., collectively referred to as a special structure of bacteria, which is also worth discussing. Because the nutrient cells in normal growth have no spores, while the cells are not present when the spores are formed. Although some bacteria remains after some bacteria and spore formation, the bacteria has lost the role of nutrient cells, and no life is lifted like a bacterium at time without buds. The capsular and flagella are different, they do not affect the life activities of bacteria, accompanying the survival of nutrient cells. Therefore, the spores are regarded as an independent dormant body, which is a positive new life form or new organ, perhaps appropriate.
action
1. Classification identification of different characteristics of different characteristics, from shape, size, surface characteristics, until the relationship with the bacteria, etc., can therefore be used as a basis or reference for classification identification.
2. Scientific research materials have become a good material for studying morphological occurrence and genetic control due to the unique generation of spores.
3. The storage of the bacteria has a strong resistance to the bad environment, which maintains the vitality for decades. In the natural world, the bacteria will have a bad environment in nature, and the laboratory is a good material for the bacteria.
4. The heat resistance of spores spores in the strain contributes to the separation of spore bacteria. The bacterius suspension is heat-treated, killing all nutrient cells, and a bacterial species forming a spore can be screened.
5. Biological insecticides Some spore bacteria can produce a slycaded crystalline intrins while producing spores, referred to as a geospantine, which is a protein toxin, which can kill some insects (especially lepidoptera) The larvae. The toxicity of protein crystals is highly specialized, and other animals are completely non-toxic. Therefore, they become an ideal biological pesticide, the production of this insecticide does not need to be separated from the protein, and simply cultivate a large number of bacteria, which is harvested, dry and dry when they form spores and produce crystals. Powder can be.
Using
spores to spend adverse environments, there is very strong resistance to drought and high and low temperatures. When the conditions are toned, 1 spores form a bacterial cell. Some bacteria spores, under dry conditions, can still germinate more than 10 years or longer, some can endure -253 ° C low temperature, some after boiling water for 30 hours, but also Spores die at 80 to 90 ° C. Therefore, the disinfection of surgical or syringe must be sterilized with high pressure. All kinds of bispococcus genus and Bacillus bobacterium can be formed in bacteria in spores. In addition, there are a small number of spiral, laceuria, and organic bacteria. Study the formation and germination of spores, it has important theoretical and practical significance. Because some bacteria that can form spores are pathogenic bacteria. In food, medicine, and the fermentation industry must completely eliminate spores of bacteria. Some spike can be used to kill the pests, such as Su Yunnacterium, Chungfacials, Chippycellophytes, etc. In forming spores, there is also a protein divider crystal, which has a strong poisonous effect on the latexue insects. Thus, these spiral bacillus were made into an insecticide, and the bacterial pesticide was carried out in terms of bacteria.
Hazard
spores also have a harmful side of humans. One of the most common situations is that when saving food with heating, spores will cause preservation failure. This is because spores heat resistance, general heating method can not kill it, it gerves have become a large amount of breeding, which will lead to corruption of food. It is therefore necessary to use high temperature sterilization (121 ° C, 30 min) to kill the spores to make the food for a long time. Medical instruments also need to be sterilized after high temperature to ensure safety. The radiation sterilization method developed in recent years has the main killing objects and spores.
Partpore crystals
Prasporalcrystal minority Bacillus, for example, Bacillusthuringiensis, which forms a rhombic shape next to the spores while forming spores or Double cone alkali-soluble protein crystal-δ endotoxin, referred to as a bore crystal. Features: insoluble in water, insensitive to protease; easily soluble in alkaline solvent. Pelicospore crystals have a poisonous effect on more than 200 insects, especially the larvae, and thus make bacteria of such product with spore crystals into bio-pesticides-bacterial pesticides conducive to environmental protection.