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    Home > Biochemistry News > Microbiology News > Culture base preparation techniques

    Culture base preparation techniques

    • Last Update: 2021-01-24
    • Source: Internet
    • Author: User
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    , the cleaning of glassware
    in the preparation of
    culture
    -base process, first of all, the use of some glassware, such as test tubes, triangular bottles, petri dishes, beers and straws. These utensils should be used in accordance with different circumstances, after a certain treatment, wash clean. Some also have to be packaged, sterilized and so on ready to use.
    1, newly purchased glassware
    after removing the dirt contaminated with packaging, first with hot soapy water brushing, water flushing, and then soaked in 1 to 2% of industrial hydrochloric acid for several hours, so that free alkaline substances removed, and then washed with running water. For larger containers, such as large cans, tubes, etc., after washing into a little hydrochloric acid, turn the container so that its internal surface is contaminated with hydrochloric acid, after a few minutes to dump hydrochloric acid, and then washed with running water, poured on the washing rack to dry water, can be used.
    2, used glassware
    Where there are no pathogens or utensils not contaminated with bacteria, after use can be flushed at any time, absorbed
    chemical reagents
    straw, can be soaked in clean water, until a certain number of then concentrated cleaning. Utensils that may be contaminated with pathogens must be properly disinfected, the dirt removed, washed with soap, and then rinsed with running water. If the utensils are not washed with soap, wash them with washing liquid for the appropriate time before washing with water. The main components of the lotion are potassium heavy chromate and thick fluid acid, which oxidize organic matter into soluble substances for flushing. Lotion has a strong corrosive effect and should be used with special care to avoid spilling on clothing, body and other items.
    II, type

    of
    bicides
    any nutritional substate suitable for
    microorganisms
    growth, reproduction or accumulation of metabolites, which is suitable for laboratory preparation, is called media. Because all kinds of microorganisms have different nutritional requirements, different culture purposes and testing needs, so there are many kinds of culture. We can class divide a wide variety of cultures into several types according to certain criteria.
    1, according to whether the chemical composition of the culture base material is fully understood to distinguish, the culture base can be divided into natural culture, synthetic culture and semi-synthetic culture base.
    1) Natural culture base Natural culture base refers to the use of a variety of animal, plant or microbial raw materials, its composition is difficult to know exactly. The main raw materials used as this type of culture are: beef paste, malt juice, protein ,
    yeast
    paste, cornmeal, bran, a variety of pie powder, potatoes, milk,
    serum
    and so on. Although the preparation of these substances of the media can not know its chemical composition, but in general, nutrition is relatively rich, microbial growth, and a wide range of sources, easy preparation, so more commonly used, especially suitable for the preparation of laboratory commonly used media. The stability of this culture base is often influenced by factors such as production plant or lot number.
    2) Synthetic culture base Synthetic culture is a class of chemical composition and quantity of well-known culture base, it is made of known chemical composition of chemicals. The culture's chemical composition is precise, repetitive, but expensive, and microorganisms grow slowly, so it is only suitable for scientific research, such as nutrition, metabolism.
    3) Semi-synthetic medium Add one or more natural ingredients to a synthetic medium, or in a natural medium, a chemical with one or more known ingredients is a semi-synthetic medium. For example, potato sucrose culture base. This type of culture is most used in production practices and laboratories.
    2, according to the physical state of the culture base, can be divided into solid culture, liquid culture base and semi-solid culture base.
    1) The culture base made of liquid culture base is liquid, the composition of which is basically soluble in water, there is no obvious solids, liquid culture base nutrients are evenly distributed, easy to control the growth metabolic state of microorganisms.
    2) Solid medium Add a suitable amount of coagulant to the liquid medium to form a solid medium. Substances commonly used as gels are
    agar
    gelatin, silicone, etc., with agar most commonly used. Solid media are widely used in practice. In the laboratory, it is used for microbial isolation, identification, testing of clutter, counting, preservation, biometrics, etc.
    3) Semi-solid medium if a small amount of solidizer is added to the liquid medium, a semi-solid medium is made. Agar, for example, is used between 0.2 and 1%. This culture can sometimes be used to observe the dynamics of microorganisms and sometimes to preserve species.
    3, according to the use of the culture base to distinguish, can be divided into the selection of culture base, proliferation of culture base, identification of culture base and so on.
    1) Choose a medium to add a substance to the medium to kill or inhibit the growth of unwanted strains, called a selection medium. Such as streptomycin, chloramphenicocin and other inhibit the growth of primary nuclear microorganisms, while moldycin, gray aflatoxin, etc. can inhibit the growth of eugenic microorganisms, crystalline amethyst can inhibit the growth of Grinch-positive bacteria.
    2) Proliferative media In nature, different kinds of microorganisms often live together, in order to isolate the microorganisms we need, in the ordinary medium to add some microorganisms particularly like nutrients, to increase the rate of reproduction of this microorganism, gradually eliminate other microorganisms, this medium is called proliferation medium, this medium is often used in species screening and selection of proliferative bacteria. To some extent, the proliferation of cultures is also a choice of cultures.
    3) Identification medium Adds a
    reagent
    or chemical to the medium, making it difficult to distinguish microorganisms that show significant differences after culture, thus helping to quickly identify a microorganism. Such a media is called a identification media. For example, the Ir red melanie blue medium used to check whether intestinal pathogenic bacteria are found in drinking water and dairy products is a commonly used identifying medium.
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