Anabiosis(redirected from anabiotic)
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the condition of an organism in which the life processes, such as metabolism, are temporarily suspended or slowed down to such a degree that visible manifestations of life are absent. Anabiosis is observed when there is an abrupt deterioration of certain conditions—low temperature, the absence of moisture, and so forth—of existence of organisms in various stages of development. With the advent of favorable conditions there is a resumption of the normal level of life processes—this may be termed “revival.” Thus, anabiosis is the biological adaptation of an organism to unfavorable external conditions, worked out in the process of evolution.
Virus particles (virions) outside bacterial, plant, or animal cells are found in a state of anabiosis (virospores), in which they readily tolerate chilling, drying, and other unfavorable influences. Anabiosis is also widespread among microorganisms. Spore-forming bacteria and microscopic fungi are the most resistant to drying, chilling, and heating. The spores of the anthrax bacillus do not lose their viability for many years, either in the dry soil of the desert or in the frozen soil of the arctic tundra. Many bacteria that do not form spores are viable even after prolonged refrigeration, which permits the isolation of pure cultures from corpses, for example. (Under ordinary circumstances, other microflora hinder this.) In many organisms the depression and almost complete cessation of life activities have become a part of the normal cycle of development (seeds, spores, and cysts). The so-called latent life of the seeds of many plants which retain their germinating capacity under dry conditions for 50 years or longer is a typical example of anabiosis under desiccation (anhydrobiosis). Anabiosis in animals was discovered by A. Leeuwenhoek in 1701. Invertebrates (hydras, worms, barnacles, marine and terrestrial mollusks, and certain insects) and vertebrates (amphibians and reptiles) may lose one-half or even three-fourths of their tissue fluid. The winter hibernation of mammals has much in common with anabiosis under freezing, and their summer hibernation has much in common with anabiosis under desiccation. The Russian scientist P. I. Bakhmet’ev and a number of Soviet investigators have established the principles that characterize anabiosis on freezing in insects and mammals. As shown by experiments on exposing small animals to low temperatures of –90°C and –160°C, revival of animals that have lapsed into anabiosis occurs only when the tissue fluids remain at a supercooled, or liquid, state at a low temperature. This is possible when there is an instantaneous conversion of water into an amorphous vitreous mass. When there is formation of ice crystals which destroy the structures of cells and protein molecules, revival is impossible.
The phenomen of anabiosis under drying and cooling conditions is used in the manufacture of dry live vaccines; for prolonged preservation of bacteria cultures, viruses, and tumor cells; and for the conservation of various tissues and organs (blood, cartilage, bone, blood vessels, and so forth) necessary for transplants. The phenomenon of anabiosis is of special interest in connection with progress on heart, lung, and brain surgery, which frequently requires chilling of the patient’s body, and with the prospect of conquering cosmic space. Anabiosis increases body resistance to the influence of factors of cosmic flight. It is also useful in connection with the artificial insemination of farm animals; the sperm of valuable specimens is thus preserved at low temperatures.
REFERENCESShmidt, P. Iu. Anabioz, 4th ed. Moscow-Leningrad, 1955. (Bibliography.)
Kalabukhov, N. I. Spiachka zhivotnykh, 3rd ed. Kharkov, 1956. (Bibliography.)
Smith, O. Biologicheskoe deistvie zamorazhivaniia i pereokhlazh-deniia. Moscow, 1963. (Bibliography; translated from English.)
N. I. KALABUKHOV