Nitrites produced in trace amounts from nitrates. Aerobic. Optimum temperature, 25° C. Antagonistic properties: Weakly antago- nistic. Some strains produce actinomycin. Comment: Represents a large group of closely related forms. Source: Isolated from soil. Habitat: Soil. 69. Streptomyces ruber (Krainsky, 1914) Waksman and Henrici, 1948. (Actino- myces ruber Krainsky, Cent. f. Bakt., II Abt., 41, 1914, 662; also see Waksman, Soil Sci., 8, 1919, 149; not Actinomyces ruber Sanfelice, Cent. f. Bakt., I Abt., Orig., 36, 1904, 355; Waksman and Henrici, in Manual, 6th ed., 1948, 946.) ru'ber. L. adj. ruber red. Aerial mycelium: Straight, branching, radiating. A few spirals may be formed. Gelatin stab: Liquefaction, with yellow flakes. Agar: Restricted, elevated, wrinkled, olive-green growth. Synthetic agar: Abundant, spreading, red growth. Aerial mycelium abundant, cottony, chrome-orange. Starch agar: Abundant, spreading, red growth. Glucose agar: Restricted, abundant, entire, coral-red growth. Glucose broth: Red ring, with spongy colonies on the surface. Litmus milk: Dark ring with red tinge; coagulated; peptonized, with alkaline re- action. Potato: Elevated, wrinkled, greenish growth. Soluble brown pigment formed. Starch is hydrolyzed. Nitrites produced from nitrates. Aerobic. Optimum temperature, 37° C. Antagonistic properties: Strongly effec- tive against various bacteria. Source: Isolated from soil. Habitat: Soil. 70. Streptomyces niger (Rossi-Doria, 1891, emend. Krassilnikov, 1941) Waksman, 1953. {Streptotrix (sic) nigra Rossi-Doria, Ann. d. 1st. d'Ig. sper. d. Univ. di Roma, 1, 1891, 419; Actinomyces niger Krassilnikov, Guide to the Actinomycetes, Izd. Akad. Nauk, U.S.S.R., Moskau, 1941, 53; Waks- man, in Waksman and Lechevalier, Actino- mycetes and Their Antibiotics, Baltimore, 1953, 78.) ni'ger. L. adj. niger black. Vegetative growth: Not compact, of soft consistency, lumpy, dark colored. In old cultures, the mycelium is readily disinte- grated into fine particles that can serve for reproduction. Aerial mycelium : Produced only on potato and synthetic agar. Sporophores produced only seldom; form open spiral with 3 to 5 turns. Spores ellipsoidal. Gelatin: No liquefaction in 30 days. Agar: Black growth. Soluble brown pig- ment. Synthetic agar: Black growth. Aerial mycelium dark gray. No soluble pigment. Starch agar: No growth. Sucrose not inverted. Milk: No change. No growth on cellulose. Nitrites not produced from nitrates. Optimum temperature, between 25° and 30° C. Antagonistic properties: None. Comment : This is a very unstable species and rapidly dies out. It easily mutates, giv- ing rise to colorless cultures, producing no aerial mj'celium. Source: Isolated from soil. Habitat: Soil. 71. Streptomyces alboniger Hesseltine et al., 1953. (Hesseltine, Porter, Deduck, Hauk, Bohonos and Williams, Mycologia, 1953; quoted from Waksman, in Waksman and Lechevalier, Actinomycetes and Their Antibiotics, Baltimore, 1953, 78.) al.bo'ni.ger. L. adj. albus white; L. adj. niger black; M.L. adj . alboniger white-black. Description prepared bj^ Hesseltine et al. for use in Waksman and Lechevalier, Ac- tinomycetes and Their Antibiotics, Balti- more, 1953. Vegetative growth: Moist, colorless to yellowish, to dark brown or black. Aerial mycelium: White to pale olive-buff. Irregularly branched sporophores, erect to
