SPECIES OF STREPTOMYCES 69 



Synthetic agar: Growth spreading, cream-colored with dark center, be- 

 coming dark green; reverse yellowish to light cadmium. Aerial mycelium 

 abundant, spreading, white, becoming light green. 



Nutrient agar: Growth abundant, restricted, gray, with greenish tinge. 



Glucose agar: Growth abundant, spreading, wrinkled, gray, becoming 

 black. 



Potato: Growth abundant, gray-brown. 



Gelatin: Surface growth cream-colored, becoming greenish. Liquefaction 

 slow. 



Milk: Surface growth dark brown; coagulation, peptonization. 



Starch: Colonies circular, spreading, yellowish. Hydrolysis positive. 



Glucose broth: Dense, solid ring, brownish, becoming dark green. 



Nitrate: Reduction to nitrite. 



Temperature: Optimum 37°C. 



Antagonistic properties: Active upon fungi. 



Remarks: Soluble brown pigment formed. 



52. Streptomyces purpeochromogenus (Waksman and Curtis) Waks- 

 man and Henrici. (Waksman, S. A., Soil Sci., 1, 1916, 113.) 



Aerial mycelium: Branching mycelium and hyphae with few imperfect 

 spirals. Conidia spherical, 0.75-1.0 \i in diameter. 



Synthetic agar: Growth slow, restricted, smooth, gray, becoming brown 

 with purplish tinge; center raised. Margin yellow. 



Nutrient agar: Growth gray to brownish, becoming dark brown, almost 

 black. 



Glucose agar: Growth abundant, restricted, gray, becoming brown to 

 dark brown. 



Potato: Growth restricted, orange to orange-red. 



Gelatin: Surface growth slow, brownish. Liquefaction slow. 



Milk: Ring dark brown; coagulation; peptonization slow, with faintly 

 alkaline reaction. 



Starch: Colonies small, dark brown. Hydrolysis slight. 



Glucose broth : Sediment slight, flaky. 



Nitrate: No reduction to nitrite. 



Temperature: Optimum 25°C. 



Antagonistic properties : Active against various bacteria. 



Remarks : Soluble dark brown pigment formed. 



53. Streptomyces phaeochromogenus (Conn) Waksman and Hen- 

 rici. (Conn, H. J., N. Y. Agr. Exp. Sta. Tech. Bull. 60, 1917, 60.) 



Aerial mycelium: Branching filaments and hyphae, spirals narrow, open, 

 elongated, sinistrorse. 



