ACTINOPHAGE

From Big Medical Encyclopedia

ACTINOPHAGE (Greek aktis, aktinos — a beam + phagos — devouring; synonym streptomikofag) — the virus causing a lysis of actinomycetes. For the first time a lysis of culture of an actinomyce under influence And. S.F. Dmitriyev in 1934, and Vibols and Viringa observed (G. L. W. Wiebols, K. T. of Wieringa) in 1936 allocated And. from natural substrates. Reproduction And. is the reason of a lysis and falling of antibiotic activity of actinomycetes at industrial cultivation.

And. are widespread in the nature everywhere where conditions of dwelling are favorable for reproduction of actinomycetes (the soil, composts, plants and so forth). Big role in distribution and survival And. play lysogenic actinomycetes which are the main source of emergence of a phage by industrial production of antibiotics. The lysogenic condition of actinomycetes can be supported by a genome And., built in a chromosome of an actinomyce. The main properties of truly lysogenic culture is immunity to new infection with it And. and the hereditary ability which is implemented regarding population to allocate a phage as a result of spontaneous induction. Among actinomycetes defective and lysogenic, polylysigenic and pseudo-lysogenic cultures have a wide spread occurance.

Almost everything investigated And. consist of the hexagonal head and a tail shoot varying in a form and the sizes and contain double-helix DNA. Different And. have hereditary distinctions in morphology of negative colonies, a range of lytic action, antigenic properties, in reaction to influences physical. and chemical factors.

U A. the following types of mutations are found: on morphology of negative colonies, a range of lytic action, virulent, with the broken ability to lysogenization, thermoinduced, temperaturo-sensitive. Ability is known And. to genetic transduction and a recombination.

Infectious cycle A. has stages, similar to a bacteriophage: adsorptions, intracellular development and an exit of posterity of a phage at a lysis of an actinomyce. Parameters of an infectious cycle (an absorption rate, a harvest of a phage etc.) hardly give in to the quantitative account because of more difficult, than at bacteria, a structure of actinomycetes and existence at them a konidialny stage.

Bibliography: Rautenstein Ya. I. A lysogeny and its biological value, in book: Usp. mikrobiol., under the editorship of A. A. Imshenetsky, century 7, page 223, M., 1971; Tikhonenko A. S. Ultrastructure of viruses of a bacterium, M., 1968.

N. D. Lomovskaya.

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