SPECIES OF STREPTOMYCES 77 



Antagonistic properties: Certain strains of this organism produce an 

 antibiotic, designated as strep tin. 

 Remarks: Soluble dark brown pigment formed in organic media. 



66. Streptomyces flavus (Krainsky) Waksman and Henrici. (Krain- 

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



Aerial mycelium: Coarse filaments with branching hyphae. Conidia 

 formed by budding and breaking up of hyphae into oval forms. 



Synthetic agar: Colonies circular, yellow or sulfur-yellow. Aerial myce- 

 lium straw-yellow. 



Nutrient agar: Growth gray, spreading, folded. 



Glucose agar: Growth restricted, raised, folded, sulfur-yellow, center 

 shading to brown. 



Potato: Growth elevated, much wrinkled, greenish olive. 



Gelatin: Small, yellowish masses on surface of liquefied medium. 



Milk: Coagulation and peptonization. 



Starch: Growth spreading, cream-colored with pink tinge. Hydrolysis 

 marked. 



Glucose broth: Colonies in bottom of tube small, white. 



Nitrate: Reduction to nitrite slight. 



Temperature: Optimum 25°C. 



Antagonistic properties: Weakly antagonistic. Some strains produce acti- 

 nomycin. 



Remarks: Represents a large group of closely related forms. 



67. Streptomyces ruber (Krainsky) Waksman and Henrici. (Krain- 

 sky, A., Centrbl. Bakt. II, 41, 1914, 639-688.) 



Aerial mycelium: Straight, branching, radiating. A few spirals may be 

 formed. 



Synthetic agar: Growth abundant, spreading, red. Aerial mycelium abun- 

 dant, cottony, chrome-orange. 



Nutrient agar: Growth restricted, elevated, wrinkled, olive-green. 



Glucose agar: Growth restricted, abundant, entire, coral-red. 



Potato: Growth elevated, wrinkled, greenish. 



Gelatin: Liquefaction, with yellow flakes. 



Milk: Dark ring with red tinge; coagulation; peptonization, with alkaline 

 reaction. 



Starch: Growth abundant, spreading, red. Hydrolysis. 



Glucose broth: Red ring, with spongy colonies on the surface. 



