What is the medium? species of medium
mediumIt also contains antibiotics and pigments. According to the different raw materials used, it can be divided into two categories: those prepared with natural ingredients such as broth and potato juice are called natural media; those prepared with chemicals and marked with ingredients are called synthetic media or comprehensive media. The media in chemical reagents are mostly synthetic media. Since liquid media is not easy to store for a long time, they are now converted into powder. The media is prepared with different raw materials, and the use requirements are different, and the storage and storage are also slightly different. Generally, the media is easily contaminated by bacteria or decomposed and deteriorated after being heated and moisture-absorbing, so the general medium must be kept in a moisture-proof, dark and cool place. For some media that require strict sterilization (such as tissue culture media), long-term storage must be placed at 2 to 6. In the refrigerator of C.
Type of medium:
Chemical classification:
① Natural medium
It refers to a medium made of natural substances with unclear chemical composition, such as chicken liver grinds and human plasma.
② Combination medium
Also known as synthetic medium or comprehensive medium, it is a kind of medium formulated with a variety of high-purity chemical reagents after precise design according to the nutritional requirements of microorganisms. Such as glucose ammonium salt medium, starch nitrate medium, etc.
③ Semi-combination medium
Refers to a class of media mainly prepared with chemical reagents, but also with some or some natural ingredients. For example, potato cane sugar medium.
Physical classification:
① Liquid medium
80% to 90% is water, which contains a medium containing soluble or insoluble nutrients.
② Solid medium
A kind of prepared solid state substrate. According to the nature, it can be divided into solidified medium, non-reversible solidified medium, natural solid medium and filter membrane.
③ Semi-solid medium
Refers to a semi-solid medium prepared by adding a small amount of coagulant to the liquid medium.
④ Dehydrated medium
Also known as prefabricated dry medium, it refers to a commercial medium containing all ingredients except moisture.
Classification of microorganisms:
① Selective medium: a type of medium designed according to the special nutritional requirements of a microorganism or its resistance to certain chemical and physical factors, which has the function of turning the inferior bacteria in the mixed bacteria into the dominant bacteria. It is widely used in ② Identification medium: a kind of medium that adds an indicator that can react with the colorless metabolites of the target bacteria in color, so that the target bacteria can be easily identified from the similar colonies by only using the naked eye to distinguish the color. For example, eosin blue lactose medium (EMB).
Media precautions:
Confirm whether the working cell bank is contaminated, confirm whether the working seed batch of poison seeds is contaminated, and confirm whether the medium used and its added ingredients (such as calf serum, NaHCO3, etc.) are contaminated. Bacteria, fungi and mycoplasma sterility tests can be used to confirm and rule out. At the same time, the sensitivity of the sterile test medium should be verified. In actual production, a small amount of nutrient agar can be taken from the prepared medium and cultured in a constant temperature incubator, and pollution can be observed within 48 hours.
Other: Autoclaving equipment and filtration sterilization equipment should be verified to ensure sterilization and sterilization effects; the former should be verified before and every 6 months after production, and the latter should be verified before and after each sterilization (at least once after sterilization).
In addition, the toxic area should be strictly separated from the non-toxic area, and have their own independent air purification system and incubator. The toxic area should maintain a relatively negative pressure on the non-toxic area to prevent virus contamination of cultured cells (especially cell banks).
