88 ACTINOMYCETES 



Vegetative growth: Colonies pigmented bright orange or golden red. 

 Pigment not dissolved in medium. 



Aerial mycelium: Weakly developed; totally absent on some media. 

 Sporophores straight, short, single or branched. Spores elongated 1.0-1.3 

 by 0.7/i, cylindrical. 



Synthetic agar: Aerial mycelium well developed, velvety, white-yellow. 



Potato: Aerial mycelium well developed, of characteristic color. 



Gelatin: Liquefaction rapid. 



Starch: Hydrolysis rapid. 



Cellulose: Growth good. 



Paraffin and waxes: Growth good. 



Antagonistic properties: Weakly antagonistic. 



Remarks: Similar to Streptomyces fradiae. 



85. Streptomyces olivaceus (Waksman) Waksman and Henrici. (Waks- 

 man, S. A., Soil Sci., 7, 1919, 117.) 



Aerial mycelium: Clumps small, with straight and branching hyphae. 

 No spirals on most media. Conidia spherical and oval, 0.9-1.1 by 0.9-2.0 n. 



Synthetic agar: Growth abundant, spreading, developing deep into me- 

 dium, yellow to olive-ocher, reverse yellow to almost black. Aerial mycelium 

 mouse-gray to light drab. 



Nutrient agar: Growth white, glistening. 



Glucose agar: Growth abundant, restricted, entire, center raised. 



Potato: Growth abundant, much- wrinkled, elevated, gray, turning sulfur- 

 yellow on edge. 



Gelatin : Liquefaction ; sediment cream-colored, flaky, yellow. 



Milk: Growth faint, pinkish; coagulation; peptonization, becoming alka- 

 line. 



Starch: Growth thin, spreading, yellowish green. Hydrolysis. 



Glucose broth : Ring sulfur-yellow. 



Nitrate: Reduction to nitrite. 



Temperature: Optimum 25°C. 



Antagonistic properties: Positive. 



Remarks: The pigment formed is not soluble. 



86. Streptomyces microflavus (Krainsky) Waksman and Henrici. 

 (Krainsky, A., Centrbl. Bakt. II, U, 1914, 639-688.) 



Aerial mycelium: Well-developed, cottony, white. Spores spherical to 

 rod-shaped, often in pairs or chains, 2.0 by 2.0-5.0 ju. 



Nutrient agar: Colonies yellow; aerial mycelium in 3 to 4 weeks, yellowish 



