Nutrient media

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Nutrient substrates used in laboratory practice for the cultivation of microorganisms and other biological objects. Microbial growth depends on the availability in the medium sufficient amounts of organic and inorganic substances in the form of various salts, vitamins and other Nutritional environment should possess optimum physical and chemical properties: pH, viscosity, humidity, osmotic properties.
The most frequently as an organic component of nutrient media used products of the partial breakdown of proteins - gelatin or various meat tinctures and extracts. These components are used in the manufacture of many so-called normal nutrient media, used mostly for cultivation of microbial cultures, and which is the basis of more complex culture media. Among the regular media is meat-peptone broth and soup of Hottinger. Depending on the type of cultivated microorganism total nutrient medium containing additives of various bacterial growth factors. In some cases it may be pure vitamins, amino acids, in other - extracts all sorts of natural substrates. So, for example, for the cultivation of pathogens of brucellosis are used supplements prevara liver tissue, as the causative agent of whooping cough are cultivated on media containing blood.
For special nutritional environments include the following environment to be applied if necessary electoral identify in the investigated material of any kind of microorganism or its individual biochemical or physiological properties. Among the special culture media include the following.
Anectine, or election, and enrichment of the environment. In these environments, created favorable conditions for the development of any one type of microorganism, reproduction of all other kinds of microbes oppressed. To do this, add to the environment or nutrients that can only use the target microbe, or various factors oppression to which the germ insensitive. This type of nutrient media used for the selection and establishment of nature micro-organisms present in the tested material in a very small number compared with other forms. Examples of electoral environments are environments containing bile or bile salts and brilliant green and environment containing Selenite, which are used for separation of pathogenic intestinal bacteria. On these media suppressed the growth of Escherichia coli. For the primary crop pathogens diphtheria use a piece of horse serum, on which all other kinds of microbes grow significantly more slowly.
2. Differential diagnostic environment. These nutrient media used for the identification of bacterial cultures. The use of differential diagnostic growth media is based on the fact that the growth of bacteria occurring chemical changes of the components of the environment, which can be easily observed. As a variable component differential diagnostic growth media is most often used different protein, sugar and polyatomic alcohols, as a result of decomposition by microbes changes reaction of the environment that is considered by a colour change added to the environment indicators, the bubbles of gas, etc. are Examples of widely used differential diagnostic growth media can serve the environment so-called multicolors number used to determine the ability of microbes to brivati various sugars (environment gissa and others). Cm. also Differential diagnostic environment.