LEVINTALYA OF THE ENVIRONMENT (W. Levinthal, is mute. bacteriologist, sort. in 1886) — special environments (broth, an agar and a blood agar) applied to cultivation of the bacteria which are not growing or badly growing on usual environments.
Preparation of broth. 100 g of the meat passed via the meat grinder fill in 300 ml of a sterile distilled water. Mix is placed in a large bottle, add 10 ml 1 N of solution of hydrosodium carbonate, well mixed and leave on 1 — 2 hour in the thermostat at t ° 37 — 60 °. Add 0,5 and Pancreatinum, 2 ml 1 and. solution of hydro-sodium carbonate and 10 ml of chloroform. The large bottle is tied parchment paper, leave for days at t ° 37 °, often stirred up.
In advance prepare and sterilize buffer solution in Koch's device (8: 1000) double-base sodium phosphate in distit. to the water acidified salt to - that to pH 5,6 — 6,6.
Mix of equal amounts of meat gruel and buffer solution boil 1 min., filter via the paper filter hot and after cooling lead up pH to 7,2 — 7,4, adding necessary quantity 1 and. salt to - you or 1 and. solution of hydro-sodium carbonate. After reboiling broth is spilled in sterile ware. The broth which is previously brought to boiling will be sterilized fractionally in Koch's device by 3 days in a row. Broth is applied to cultivation of cocci.
Preparation of an agar. On buffer solution prepare 3% an agar. The agar after swelling during 1 — 2 hour is melted in Koch's device. The melted buffer agar is cooled to t ° 70 — 80 ° and mixed with an equal volume of meat gruel. Mix is brought to boiling on strong fire and boiled 1 min. The agar is decanted in a flask and again allow to boil. Immediately filter via the paper filter. The first portion is filtered twice.
1 N solution of hydrosodium carbonate lead up pH to 7,5 — 7,8 and again boil. It is better to boil in the portions 250 ml. The agar is spilled in sterile test tubes and in Koch's device 3 days in a row 10 — 15 min. carry out fractional sterilization. Wednesday shall be transparent. The agar is applied to cultivation of cocci.
Preparation of a blood agar. Usual 2% melt an agar with pH 7,3 — 7,5 and cool to t ° 45 °. Slowly at constant stirring sterilely add 5 — 10% of the defibrinated horse, rabbit or human blood to the kindled agar. Mix is warmed up in Koch's device at t ° 100 °. Duration of warming up depends on quantity of the environment; 1 l warm up 5 min., 2 l — 8 — 10 min.; at preparation of trace amounts of the environment in thin-walled flasks warm up 2 min. The superheated agar is unsuitable since at the same time rough flakes of chocolate-brown color drop out. Warming up can be carried out on the water bath: 2 — 3 min. warm up, then for 2 min. leave on a table, repeating this procedure three times. For sedimentation Wednesday leave for 2 hours at t ° 60 °. The top transparent coat is spilled sterilely on cups. For receiving a transparent agar Wednesday can be filtered sterilely through not fat-free cotton wool. The filtered environment is spilled also sterilely in test tubes and cups. Store no more than 3 weeks. Before the use the agar is checked for sterility, maintaining days in the thermostat. Wednesday is applied to cultivation of bacteria — sticks of an influenza, pathogenic cocci, etc.
See also Mediums .
Bibliography: The reference book on microbiological and virologic methods of a research, under the editorship of M. O. Birger, page 75, M., 1973; T and m and to about in V. D. and Gold-f and r D. M. Fundamentals of experimental medical bacteriology, M., 1958; L e v i n t h and I W. Nahrbouillon und Nah-ragar mit verbesserter Fleischausnutzung, Zbl. Bakt., I. Abt. Orig., Bd 121, S. 513, 1931.
I. M. Goncharenko.