74 ACTINOMYCETES 



lium white, turning light grayish lavender when sporulation occurs. No 

 soluble pigment. 



Potato: Growth abundant, spreading, brownish; aerial mycelium gray- 

 ish lavender; browning of the potato. 



Gelatin: Surface pellicle gray to brownish; aerial mycelium thin, white. 

 Brown soluble pigment extending as far as liquefied zone. Liquefaction 

 slow. 



Milk: Growth brown. No coagulation; peptonization slow. Milk be- 

 comes dark gray -brown or black. 



Starch: Growth thin colorless; aerial mycelium rose to lavender-colored. 

 Hydrolysis. 



Nutrient broth: Ring on surface thin, cream-colored; a few flakes on 

 bottom. Soluble pigment brownish. 



Nitrate: Reduction none or limited. 



Glucose-asparagine agar : Growth sparse, cream-colored ; no aerial myce- 

 lium; no sporulation; no pigmentation. 



Calcium malate agar: Growth abundant, cream-colored; aerial mycelium 

 white, becoming tinged with grayish lavender; no soluble pigment. 



Oatmeal agar: Growth abundant, cream-colored, turning golden brown; 

 aerial mycelium abundant, light rose, turning lavender and gray. Soluble 

 pigment pale yellow, turning light brown. 



Temperature: Optimum 28°-30°C. 



Antagonistic properties: Produces actithiazic acid. 



Remarks: Utilizes glucose, mannose, galactose, maltose, starch, glycerol, 

 sodium acetate, sodium citrate; does not utilize xylose, lactose, sucrose, 

 mannitol, sorbitol, potassium sodium tartrate. 



61. Streptomyces reticuli (Waksman and Curtis) Waksman and 

 Henrici. (Waksman, S. A., and Curtis, R. E., Soil Sci., 1, 1916, 118.) 



Aerial mycelium: Whorls; spirals formed on glucose agar are sinistrorse. 

 Conidia spherical, 1.0-1.4 y. in diameter. 



Synthetic agar: Growth colorless, with yellowish tinge, becoming brown- 

 ish, spreading. Aerial mycelium thin, white, cottony. 



Nutrient agar: Growth wrinkled, gray, becoming brownish. 



Glucose agar: Growth restricted, brownish, center raised. 



Potato: Growth gray, with black center. 



Gelatin: Liquefaction with small, brown flakes. 



Milk: Reaction unchanged; coagulation; peptonization. 



Starch: Growth brownish gray. Hydrolysis positive. 



Glucose broth: Sediment consisting of large colonies. 



Nitrate: Reduction to nitrite. 



Temperature: Optimum 25°C. 



