96 ACTIN0MYCETE8 



Milk: Growth rose-colored; peptonization slow. 



Coagulated serum: Growth cream-colored; aerial mycelium fine, white; 

 liquefaction slow. 



Glucose-asparagine agar: Colonies limited, cream-colored, hardly raised 

 above the surface of the medium; occasionally abundant growth produced 

 with white aerial mycelium, colorless on reverse side. 



Glucose-asparagine solution: Branching immersed filaments, 0.8 ju in di- 

 ameter; aerial mycelium 1.0 by 1.2 ju with numerous spores; flakes settle to 

 bottom of tube. 



Peptone solution : Surface colonies cream-colored. 



Tyrosine medium: Growth whitish; no pigment. 



101. Streptomyces sp. Leben, Stessel, and Keitt. (Leben, C, Stessel, 

 G. J., Keitt. G. W., Mycologia, U, 1952, 159-169.) 



Vegetative growth: On most media early growth at first white and later 

 gray; the color change appears to be associated with the development of 

 dense masses of spores. 



Aerial mycelium: Spirals situated typically in dense groups along the 

 main portions of aerial hyphae, especially toward the center of the colony. 

 In early formation of sporing hyphae, spirals tend to be open ; they become 

 closed and compact, however, prior to the formation of spores. In late 

 stages these fruiting structures tend to appear ball-like rather than spiral. 

 Spores oval, hyaline, and 0.6-1 .3 ju wide by 0.7-2.0 n long; diameter of spore 

 spirals 4-8 y.. 



Synthetic agar: Aerial mycelium abundant, pebbly, light neutral gray. 

 No diffusible pigment. 



Potato: Vegetative growth finely wrinkled, cream-colored with sparse, 

 white, aerial mycelium. Plug darkened slightly. 



Gelatin: Vegetative mycelium translucent, cream-colored; aerial myce- 

 lium sparse, white. Liquefaction slight at 15 days, moderate at 30 days. 

 No diffusible pigment. 



Milk: Growth ring cream-colored. Coagulation; peptonization in 15 to 

 30 days, becoming slightly alkaline. Serum yellowish orange, slightly turbid. 



Starch: Aerial mycelium abundant, pebbly white to neutral gray. No 

 diffusible pigment. Diastatic action weak to moderate. 



Glucose broth: Surface colonies coalescing, white, powdery. Liquid clear, 

 not pigmented. Small amount of flaky sediment present. 



Nitrate: Reduction to nitrite slight. 



Glucose-asparagine agar: Results the same as on synthetic agar. 



Glucose-peptone agar: Results the same as on synthetic agar. 



Malate-glycerin agar: Aerial mycelium abundant, pebbly, light neutral 

 gray. Diffusible pigment faint green. 



