Chemistry: molecular biology and microbiology – Micro-organism – per se ; compositions thereof; proces of... – Bacteria or actinomycetales; media therefor
Patent
1988-09-30
1990-07-03
Wax, Robert A.
Chemistry: molecular biology and microbiology
Micro-organism, per se ; compositions thereof; proces of...
Bacteria or actinomycetales; media therefor
524377, 526306, 5263072, C12N 120
Patent
active
049391500
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE ART
The present invention relates to a method for preparing a dense nutrient medium based on a polyacrylamide gel for culturing microorganisms.
STATE OF THE ART
Known in the art is a method for preparing a dense nutrient medium for culturing microorganisms by way of copolymerization of acrylamide and N,N'-methylenebisacrylamide at a mass ratio thereof equal to 15-20:0.019-0.132 in the presence of an initiator in a physiological solution till the formation of a gel, its washing and swelling in a physiological solution for 16-20 hrs at a temperature within the range of from 50.degree. to 60.degree. C., followed by impregnation with a nutrient substrate.
This dense nutrient medium has a density approaching that of agar-agar media, it is elastic and transparent. It also ensures a good sliding of a bacteriological loop upon inoculation and removal of microorganisms without damaging its surface owing to a long-time operation of swelling (16-20 hrs), thus substantially extending the duration of the entire process.
Known in the art is a method for preparing a nutrient medium for culturing microorganisms comprising copolymerization of acrylamide and N,N'-methylenebisacrylamide at a mass ratio thereof equal to 0.5-40:2.5-12.0 in the presence of an initiator in a physiological solution. The resulting polyacrylamide gel is subjected to washing and impregnation with a nutrient substrate (SU, A, 977466). This dense nutrient medium has a greater sensitivity to damages during imprenation, sterilization and inoculation of microorganisms. The removal of individual species of microorganisms from the surface of such medium by means of a bacteriological loop is rather difficult.
In the above-discussed methods the process of copolymerization is effected in special moulding apparatus without access of air to exclude the formation of a rough surface on the produced polyacrylamide gel hindering its use for the preparation of a nutrient medium. This process, therefore, has but a limited application in the mass-scale preparation of nutrient media, for example in Petri dishes and in other laboratory ware.
DISCLOSURE OF THE INVENTION
The present invention is directed to the provision of a method for preparing a dense nutrient medium for culturing microorganisms by way of using, during copolymerization, a structurization agent which would impart, to the nutrient medium, the properties similar to those of agar-agar media while ensuring a good effect of sliding of a bacteriological loop in the process of inoculation of microorganisms.
This problem is solved by the provision of a method for preparing a dense nutrient medium for culturing microorganisms which comprises copolymerization of acrylamide and N,N'-methylenebisacrylamide in the presence of an initiator in a physiological solution till the formation of a gel, washing and impregnation thereof with a nutrient substrate, wherein, according to the present invention, the copolymerization of acrylamide and N,N'-methylenebisacrylamide is carried out in the presence of a branched polyacrylamide with a mean molecular mass of 7.2.times.10.sup.4 at a mass ratio thereof equal to 7-15.0:0.11-0.21:0.028-0.11 respectively.
The method, according to the present invention, provides for a good quality of the nutrient medium at a simplified process of its manufacture. The process of copolymerization, owing to the use of the structurization agent, is readily implementable in the air atmosphere without the necessity of using special equipment.
To accelerate the reaction of copolymerization, it is advisable to use an aqueous solution of the above-mentioned branched polyacrylamide. It is desirable to use, for the impregnation of the polyacrylamide gel, a nutrient substrate containing polyethylene oxide in an amount of 0.02 to 0.2 g/l. This contributes to the formation of such a superficial monolayer on the surface of the medium which ensures a clearly pronounced effect of sliding of a bacteriological loop in inoculation of microorganisms.
THE BEST WAY OF CARRYING THE INVENTION INTO
REFERENCES:
patent: 3061595 (1962-10-01), Dorion et al.
Gashinsky Vladimir V.
Krainjukova Tatyana I.
Marchenko Nikolai N.
Onischenko Vladimir V.
Shirobokov Vladimir P.
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