ACTINOMYCETES

From Big Medical Encyclopedia

ACTINOMYCETES (Actinomycetes; Greek aktis — a beam + mykzs — a mushroom; radiant fungi) — the microorganisms relating to an order of Actinomycetales, the Actinomycetaceae family; are intermediate between bacteria and fungi.

Fig. 1. Actinomyces violaceus niger
Fig. 2. A. violaceus
Fig. 3. A. coelicolor
Fig. 4. A. aurantiacus
Fig. 5. A. aurantiacus sp
Fig. 6. A. iluorescens n. sp
Fig. 7. A. violaceo-chromogenes
Fig. 8. A. globisporus
Fig. 9. A. griseoglaucus
Fig. 10. A. lavendulae
Fig. 11. A. viridis
Fig. 12. A. griseus

Originally under this name combined microorganisms which basis of structure is the branched mycelium which is breaking up or not breaking up to rhabdoid or kokkovidny (diphtheroid) elements. Width of this mycelium does not exceed 1,5 microns, 0,7 — 0,8 microns are more often, kernels are not found.

On the basis of a radiant structure of these organisms found in the struck fabric of cattle, Harz (Harz, 1877) Actinomycetes called them and carried to mushrooms. N. A. Krasilnikov (1970) also finds that they are closer to mushrooms. Vaksman (S. A. Waksman, 1962), Avery, the Form (R. Avery, F. Blank, 1954), Pollemann (G. Pollemann, 1961) is considered that by the sizes, lack of the differentiated kernel, sensitivity to antibiotics and other signs And. closer to bacteria, and Lisk (R. Lieske, 1928) took them for those the initial forms from which there were mushrooms and bacteria.

Uncertainty of taxonomical situation A. in botanical classification led to emergence of a large number of synonyms: Oospora Wallroth (1831), Streptothrix Corda (1839), Leptothrix Kutzing (1843), Cladothrix Conn (1876), Discomyces Rivolta (1878), Micromyces Gruber (1891), Indiella Brumpt (1906), Streptomyces Waksman a. Henrici (1943), etc.



From numerous classifications And. two have practical value — H. A. Krasilnikova (1949, 1970) and Vaksman — Genritsi (1948, 1957). In both classifications the concept «actinomycetes» is narrowed to the name of one sort Actinomyces including types: Actinomyces bovis, Actinomyces israelii, Actinomyces baudetii (tab).

Fig. 1. A structure of a mycelium of actinomycetes (5-day culture on synthetic medium): 1 — Actinomyces albus Gasperini (the long, seldom branching threads); 2 — Actinomyces aurantiacus Gasperini (the short, strongly bent and often branching threads)

On Krasilnikov's classification constructed taking into account a morphological structure and phylogenetic bonds of radiant fungi, the sort Actinomyces combines organisms with well developed, neseptirovanny mycelium which does not break up to rhabdoid and kokkovidny elements. As in threads of a mycelium there are no partitions, they represent one cell (fig. 1). On agar mediums different types And. form various colonies: flat, wrinkled, smooth, hilly, filmy and so forth. The substrate mycelium growing on Wednesday departs from a lower surface of colonies; from a surface of colonies among an air mycelium sporonosets — direct or turbinal, with the number of curls to develop 10 and more (fig. 2). In sporonosets by fragmentation or segmentation disputes are formed. In the first case there is an isolation of separate lumps of protoplasm in thread of which then chains from a dispute are formed. In the second — this process is preceded by segmentation of threads of a mycelium. Disputes are spherical, oval, rhabdoid, with a smooth or acanthceous surface (fig. 3).

Pigments, different in chemical structure, cause different coloring of colonies (color silt. fig. 1 — 12). Various combinations of these pigments in the same colony create a set of various shades. Some pigments of a rastvorima in water, others (e.g., red-yellow lipoaktinokhroma) are dissolved only in alcohol or other solvents of fat. One pigments remain in cells, others diffuse on Wednesday.

Majority And. — aerobes, anaerobic or mikroaerofilny types meet seldom. Growth And. occurs at wide value rn Wednesdays from 5 to 9. The temperature optimum for the majority of types 25 — 30 ° (mesophylls), but growth is possible in the range from 3 to 40 °. Available among And. thermophiles grow at t ° 45 — 50 °.

Existence at And. a large number of various enzymes — proteases, keratinaza, a chitinase, a lipase, amylase, invertases, etc. — are increased by ability And. to use the plant and animal residues, and also such substrates which do not use other microorganisms — paraffin, kerosene, wax, pitch and so forth. Some types And. fix molecular nitrogen. Enzymatic activity is shown also in inherent And. lytic processes, e.g. an autolysis which can be caused as well by lytic impact on other microorganisms.

Many metabolites And. treat biologically active compounds — antibiotics, hormones, vitamins, enzymes and so forth. From And. it is allocated apprx. 1000 antibiotic substances, active concerning bacteria, mushrooms, viruses, the elementary, and also tumors. Many of them received broad practical application — streptomycin, Aureomycinum, oxytetracycline, etc. Antimicrobic action also some toxins A possess., napr, gliotoxin which is highly toxic for animals and plants.

Almost everything And. are capable to synthesize polyneuramin 12 and its analogs. Some types synthesize vitamins of Vkh, B2, biotin, pantothenic and nicotinic acids, a pyridoxine, Riboflavinum and so forth. Some And. are producers of amino acids — glutaminic, asparaginic, valine, methionine, cysteine, cystine, etc. Some types form aromatic substances with smells of the earth (the most characteristic for And. sign), fruit, camphor, iodoform, hydrogen sulfide, ammonia and so forth. And. are eurysynusic on all surface of the globe: there is a lot of them on the plant and animal residues, in water of natural reservoirs and especially in the soil. From 1 g of the soil it is sowed from several hundred to millions and even billions of actinomycetes, and it is less from primary, it is more from cultural soils.

And. widely participate in cycle of matter in the nature, splitting many substrates unavailable to other microorganisms, promote formation of a humus and aeration of rocks.

Vaksman and Genritsi classify radiant fungi taking into account their pathogenicity, an anaerobiosis, acid resistance and other signs. The name of the sort Actinomyces is kept by them as historically developed for pathogenic types. Vaksman and Genritsp included in a sort A. such radiant fungi which body consists of the thin, but septirovanny mycelium which is breaking up over time to rhabdoid and kokkovidny elements. These organisms pathogens, nekislotoustoychiva, grampolozhitelna, anaerobna. Colonies are leathery, dense or pasty, are sometimes covered with a rare air mycelium. Representatives of this sort cause in people and animals an actinomycosis (see).

There are many types And., causing this disease, but the following types meet more often. Actinomyces Israeli Lachner — Sandoval (1898); synonym: A. hominis Wolff — Israel (1891), Streptothrix israeli Kruss (1896), Proactinomyces israeli (Kruse) Krassilnikov (1941). Colonies are colourless, pasty, smooth, sometimes hilly; the air mycelium is presented by rare branches, does not form pigments. On With synthetic environments grows badly, better on proteinaceous with blood serum, in mikroaerofilny conditions at t ° 37 °. Microscopically consists of the fine ends of a mycelium (3 — 10×0,6 mk) which are breaking up over time on polymorphic — rhabdoid, kokkovidiy, kolbovidny, spherical, spindle-shaped — elements. Assimilates glucose, a maltose, sucrose, a galactose, fructose, lactose, mannose, on raffinose and others of sugar. Does not liquefy gelatin, does not peptonize and does not curtail milk, does not recover nitrates, starch hydrolyzes poorly. Patogenen dn for the person and some animals.

Actinomyces bovis Harz (1877); synonym: Discomyces bovis Rivolta (1878), Cladothrix bovis Mace (1891), Nocardia actinomyces Trevisan (1889), Proactinomyces bovis (Wright) Krassilnikov (1941). Colonies are colourless, pasty, sometimes leathery, covered with a white air mycelium which breaks up to a game rhabdoid and kokkovidny elements. Sporonostsa on an air mycelium slightly wavy, but not spiral. Anaerobe. Well grows on proteinaceous environments at t ° 37 °. Does not liquefy gelatin, does not ferment milk, does not hydrolyze starch. Assimilates glucose, a galactose, fructose, mannose, glycerin; more weakly — a maltose, sucrose, inulin, a mannitol, dulcite, lactose. Under natural conditions strikes cattle, horses, pigs and other animals, occurs also at the person.

Organisms of the same structure, but growing in aerobic conditions and partially acid resisting Vaksman and Genritsi allocated in the special sort Nocardia which representatives cause in people and animals a disease — a nocardiosis (see).

Pathogenic types And. live in the surrounding nature, but hl meet as saprophytes in an organism of people and animals. obr. in an oral cavity (in a dental calculus, a dental plaque) therefore infection with an actinomycosis can be both exogenous, and endogenous.

The sort Proactinomyces, or Nocardia (across Krasilnikov), includes two sorts — Actinomyces and Nocardia Waksman a. Henrici, and also numerous saprophytic types of the same structure.

Among activators of an actinomycosis there are representatives of the sort Micromonospora which enters also an extensive class of radiant fungi Actinomycetes, this. Micromonosporaceae (across Krasilnikov) or Streptomycetaceae (across Vaksman and Genritsi). They cause a disease — a micromonosporosis (see). The structure of micromonospores is similar to that at Actinomyces and Proactinomyces. Difference consists in a way of formation a dispute (conidiums) which are formed on one on the end of sporonosets. In the nature meet less than And. From pathogenic types Micromonospora parva Jensen (1932) are most frequent. Colonies are flat, naked, with rare conidiophores on whose ends on a leg or directly on thread of a mycelium one oval a dispute; these disputes in weight have grayish-greenish coloring. The orange pigment of colonies does not diffuse on Wednesday. Mezofila. Aerobes. Chemically maloaktivna: to gelatin liquefy poorly, do not change milk, hydrolyze starch.

Micromonospora monospora (Lehmann, Schiitze) Jensen (1932); synonym: Actinomyces monosporus Lehmann, Schutze (1908), Thermoactinomyces monosporus Waksman (1961). Colonies are covered with an air mycelium, conidiophores bear on one oval a dispute. Color of colonies yellow or gray-green. A temperature optimum 37 °, maintain short-term heating to 55 — 75 ° above. To gelatin liquefy, do not change milk. Aerofila.

S.F. Dmitriyev described also eurysynusic among pathogenic And. phenomenon of a spontaneous lysis. This property A. use for receiving drug — an aktinolizat who in the USSR apply to treatment and diagnosis of an actinomycosis.

Bibliography: Vaksman S.A. About classification of actinomycetes, Microbiology, t. 33, century 6, page 1078, 1964, bibliogr.; Dmitriyev S. F. The phenomena of dissociation and a snap lysis in culture of an actinomyce, Zhurn. mikr., epid. and immun., t. 13, No. 2, S. 289, 1934, bibliogr.; it, About variability of the activator of an actinomycosis in connection with its stay in an organism of the patient, Medical parazitol., t. 9, century 1-2, page 128, 1940; Krasilnikov N. A. Determinant of bacteria and actinomycetes, M. — L., 1949, bibliogr.; it, About terminology of actinomycetes and pro-actinomycetes, Microbiology, t. 32, century 6, page 988, 1963, bibliogr.; it, Radiant fungi, M., 1970; Waksman S. A. The actinomycetes, N. Y., 1967, bibliogr.

Z. G. Stepanishcheva.

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