CRYOPHILIC BACTERIUMS

From Big Medical Encyclopedia

CRYOPHILIC BACTERIUMS (cold + phileo to love Greek psychros; bacteria) — bacteria, formative at low temperatures. Item. make big group of saprophytic microorganisms — inhabitants of the soil, the seas, fresh reservoirs, drain waters. Some iron bacteria, pseudo-monads, clostridiums, bacilli concern to them (Bacillus globisporus, you. psychrophilus, etc.), vibrioes (Vibrio fischeri, etc.). Item. sometimes cause damage of food stuffs in refrigerating conditions. P.'s number. consider along with other microorganisms during the determination of the general level of microbic pollution of objects of the environment.

Some P. depending on temperature change the properties.

E.g., the activator of a pseudotuberculosis Yersinia pseudotuberculosis can breed at t ° 4 °, at t ° 22 ° it forms flagellums and is mobile, and at t ° 37 ° mobility loses. Depending on temperature of cultivation also other properties of bacteria change. So, synthesis of polysaccharides of bacteria, including capsular, is higher at lower temperatures of an incubation in those limits of temperatures at which growth is possible.

The interval of temperatures, at Krom is possible P.'s growth., strongly varies for various bacteria and fluctuates from — 10 to +40 °. Small part of P. it is formative at t ° — 10 ° if in the habitat there are salts in the concentration preventing freezing of the environment. For P. enough proliferation at t is characteristic ° 0 — 5 °. Bacteria for which the upper limit of temperature of growth is higher 20 ° are called optional psikhrofila; Item., growing at a temperature below 20 °, consider obligate psikhrofila.

Assume that delay and the termination of growth of P. at temperature increase above optimum it is connected with a denaturation of enzymes, in particular respiratory. Item. differ from the bacteria growing at more high temperatures (see. Thermophilic bacteria ), physical. - chemical properties of proteins and lipids. So, e.g., the bacteria allocated from the Antarctic waters contain many proteins, very heat-sensitive. It is shown that some bacteria which are grown up at low temperatures contain the increased quantity unsaturated fat to - t in lipids that, apparently, promotes preservation at low temperatures of the liquid state of lipidic components of membranes necessary for their functioning.

See also Bacteria .


Bibliography: Pole S. P. Adaptation of microorganisms to low temperatures, M., 1976, bibliogr.; P e r t of Page D. Bases of cultivation of microorganisms and cells, the lane with English, M., 1978, bibliogr.; G. P som. Far East scarlatiniform fever, M., 1979, bibliogr.; Steyniyer R., E d e l-berg E. and Ingram D. The world of microbes, the lane with English, t. 2, M., 1979.

A.S. Bykov.

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