Habitat: Found in wheat soil so far as known. 66. Streptoniyces circulatus (Krassil- nikov, 1941) Waksman, 1953. {Actinomyces circulatus Krassilnikov, Guide to the Acti- nomycetes, Izd. Akad. Nauk, U.S.S.R., Moskau, 1941, 60; Waksman, in Waksman and Lechevalier, Actinomycetes and Their Antibiotics, Baltimore, 1953, 76.) cir.cu.la'tus. L. part. adj. circulatus curled. Vegetative growth: Better on synthetic media than on organic media. Aerial mycelium: Spiral-producing sporo- phores formed in whorls. Spores cylindrical, oblong, 0.7 by 1.5 microns, some rounding up as culture ages. Gelatin: Weak liquefaction. Agar: Poor growth. No aerial mycelium. Synthetic agar: Good growth, producing abundant, white aerial mycelium. Milk: Not coagulated; slowly peptonized. Sucrose not inverted. Starch is weakly hydrolyzed. No growth on cellulose. Nitrites weaklj^ produced from nitrates. Antagonistic properties : Limited. Source: Isolated from soil. Habitat: Soil. 67. Streptomyces rubrireticuli Waks- man and Henrici, 1948. {Actinomyces reticu- lus-ruber Waksman, Soil Sci., 8, 1919, 146; Actinomyces reticulus Bergey et al.. Manual, 2nd ed., 1925, 373; Waksman and Henrici, in Manual, 6th ed., 1948, 945.) ru.bri.re.ti'cu.li. L. adj. ruber red; L. noun reticulum a small net; M.L. gen. noun rubrireticxdi of a small red net. Aerial mycelium: Branching filaments with both primary and secondary whorl formation. Spirals formed on glucose agar. Conidia ellipsoidal. Gelatin stab: Surface growth yellowish red to dragon -pink. Liquefaction. Agar: Red growth, with yellowish margin becoming red. Synthetic agar: Abundant, spreading growth, usually pink. Aerial mycelium thin, rose to pink. Starch agar: White growth with red tinge. Glucose agar: Abundant, spreading, rose -red, entire growth. Glucose broth: Thin, flaky sediment. Litmus milk: Abundant, red pellicle; coagulated; peptonized. Reaction un- changed. Potato: Cream-colored growth, later pink to dark red. Soluble dark brown pigment formed. Starch is hydrolyzed. Good growth on cellulose. Nitrites produced from nitrates. Aerobic. Optimum temperature, 37° C. Antagonistic properties: Certain strains of this organism produce an antibiotic, designated as streptin. Source: Isolated from a New Jersey orchard and from California upland soils. Habitat: Soil. 68. Streptomyces flavus (Krainsky, 1914) Waksman and Henrici, 1948. {Actino- myces flavus Krainsky, Cent. f. Bakt., II Abt., 41, 1914, 662; also see Waksman and Curtis, Soil Sci., 1, 1916, 118; not Actino- myces flavus Sanfelice, Cent. f. Bakt., I Abt., Orig., 36, 1905, 359; Waksman and Henrici, in Manual, 6th ed., 1948, 945.) fla'vus. L. a,d]. flavus yellow. Aerial mycelium: Coarse filaments with branching hyphae. Conidia formed by bud- ding and breaking up of hyphae into ellip- soidal forms. Gelatin stab: Small, yellowish masses on surface of liquefied medium. Agar: Gray, spreading, folded growth. Synthetic agar: Circular, yellow or sulfur- yellow colonies. Aerial mycelium straw- yellow. Starch agar: Spreading, cream-colored growth, with pink tinge. Glucose agar: Restricted, raised, folded, sulfur-yellow growth, center shading to brown. Glucose broth: Small, white colonies in bottom of tube. Litmus milk: Coagulated; peptonized, becoming distinctly alkaline. Potato: Elevated, much wrinkled, green- ish olive growth. Soluble brown pigment formed. Starch is hydrolyzed.
