Starch agar: Abundant growth. Aerial mycelium white, becoming gray. Glucose agar: Aerial mj^celium gray. Soluble deep brown pigment. Broth: Abundant, white surface pellicle. Soluble deep brown pigment. Milk: Patchy, white surface growth. Aerial mycelium gray. Gradual hydrolysis. Potato: Wrinkled, raised, pale ocherous buff growth. Soluble pigment brown to black. Starch is weakly hydrolyzed. Antagonistic properties: Strongly antago- nistic. Produces streptomycin. Source: Isolated from soil from Bikini atoll. Habitat: Soil. 47. Streptoniyces niirabilis Rusch- mann, 1952. (Die Pharmazie, 7, 1952, 542.) mi.ra'bi.lis. L. adj. mirahilis miracu- lous, extraordinary. Aerial mycelium: White fluff}- layer con- sisting of abundant aerial mycelium and spores. Hyphae straight, without spirals or curvature; sporulation takes place after 6 to 7 days. Gelatin: Good, flaky growth. Liquefac- tion rapid. Soluble dark brown to black pig- ment. Agar: Poor growth with slimy surface, resembling that of bacteria. No sporulation. Glucose agar: Grayish brown, slimy growth. No aerial mycelium even after 14 days. Soluble brown pigment. Carrot juice agar: Good growth in form of round colonies covered with white aerial mj^celium. Each colony produces 3 to 5 cracks or holes in center. Czapek's solution: Limited growth in the form of a few surface colonies, sinking rap- idly to the bottom. Milk: Surface growth with white, fluffy aerial mycelium. Milk coagulated and pep- tonized. Liquefied portion colored black. Reaction of medium unchanged. Potato: Good, lichenoid growth. Soluble dark brown to black pigment. Fats are readily utilized. Oxygen requirement: Quite considerable. Optimum temperature, 29° C. No growth at 37° C. Antagonistic properties: Produces mira- mycin. Antagonistic effect strongest in freshly isolated cultures. Property lost on cultivation; activity upon Gram-positive bacteria is lost first, then upon Gram-nega- tive rods; cocci remain most sensitive. Distinctive characters: Highly proteo- lytic and lipolytic. Grows best on complex organic media. Grows best at slightly acid reaction or pH 6.0 to 6.6. Source: Presumably isolated from soil. Habitat: Soil. 48. Streptoniyces antibioticus (Waks- man and Woodruff, 1941) Waksman and Henrici, 1948. {Actinomyces antibioticus Waksman and Woodruff, Jour. Bact., 4^, 1941, 232 and 246; Waksman and Henrici, in Manual, 6th ed., 1948, 942.) an.ti.bi.o'ti.cus. Gr. pref. anti against; Gr. noun bins life; M.L. adj. antibioticus against life, antibiotic. Aerial mj'celium: Spore-bearing hyphae produced in the form of straight aerial hyphae. The conidiophores are arranged in clusters; no spirals formed. The conidia are nearly spherical to somewhat ellipsoidal. Gelatin: Dark brown growth on surface with patches of gray aerial mycelium. Dark pigment produced which gradually diffuses into the unliquefied part of the gelatin. Liquefaction at first very slow, later be- coming rapid. Agar: Production of dark pigment at early stage of growth is very characteristic. Growth brownish, thin, with a yellowish gray to yellowish green aerial mycelium. Synthetic agar: Thin, whitish growth. Thin, gray aerial mycelium. Litmus milk: Thick, brownish ring on surface of milk. Mouse-gray aerial mycelium with greenish tinge; growth becomes brown, especially in drier portions adhering to glass. No reaction change, no coagulation of milk, no clearing; whitish sediment at bottom of tube. Old cultures: heavy growth ring on surface of milk, heavy precipitation on bottom; liquid brownish to black in upper portion. Potato plug: Folded, brown-colored growth with a thin black ring on plug, fad- ing into a bluish tinge. No aerial mycelium.
