FAMILY STREPTOMYCETACEAE 



953 



Litmus milk: Cream-colored ring; co- 

 agulated; peptonization with alkaline re- 

 action. 



Potato: Abundant, cream-colored, 

 wrinkled growth. 



Nitrites produced from nitrates. 



The pigment formed is not soluble. 



Starch is hydrolyzed. 



Aerobic. 



Optimum temperature 25°C. 



Source : Isolated many times from a 

 variety of soils. 



Habitat: Common in soil. 



47. Streptomyces halstedii (Waksman 

 and Curtis) comb. nov. (Actinonnjces 

 halstedii Waksman and Curtis, Soil 

 Science, 1, 1916, 124.) Named for a 

 person. 



Branching mycelium and hyphae with 

 close spirals. Conidia oval or rod- 

 shaped, 1.0 to 1.2 by 1.2 to 1.8 microns. 



Gelatin stab: Liquefied, with small, 

 cream-colored masses in bottom of tube. 



Synthetic agar: Growth abundant, 

 heavy, spreading, raised, light, becoming 

 dark, almost black. Aerial mycelium 

 white, turning dull-gray. 



Starch agar : Abundant, brownish, 

 glossy growth. 



Glucose agar : Growth spreading, color- 

 less, wrinkled, center elevated, edge 

 lichenoid, becoming brown. 



Plain agar: Restricted, wrinkled, 

 cream-colored growth. 



Glucose broth : Small, colorless colonies 

 in bottom of tube. 



Litmus milk: Cream-colored ring; co- 

 agulated; peptonized, becoming alkaline. 



Potato : Growth abundant, moist, 

 wrinkled, cream-colored with green tinge. 



Nitrites produced from nitrates. 



The pigment formed is not soluble. 



Starch is hydrolyzed. 



Optimum temperature 37 °C. 



Aerobic. 



Source : Isolated many times from the 

 deeper soil layers. 



Habitat: Common in subsoil. 



48. Streptomyces hygroscopicus (Jen- 



sen) comb. nov. (Actinomyces hygro- 

 scopicus Jensen, Proc. Linn. Soc. New 

 So. Wales, 56, 1931, 257.) From Greek, 

 hygroscopic. 



Hyphae of vegetative mycelium 0.6 to 

 0.8 micron in diameter. Aerial liyphae 

 long, tangled, branched, 0.8 to 1.0 micron 

 in diameter; spirals numerous, sinis- 

 trorse, narrow, usually short, only 1 or 2 

 turns, closed, typically situated as dense 

 clusters on the main stems of the aerial 

 hyphae. Conidia oval, 0.8 to 1.0 by 

 1.0 to 1.2 microns. 



Gelatin: Slow liquefaction. No pig- 

 ment produced. 



Nutrient agar: Good growth. Vegeta- 

 tive mycelium raised, wrinkled, glossy, 

 cream-colored; later yellowish-gray with 

 yellowish-brown reverse. Occasionally 

 a scant white aerial mycelium. 



Sucrose agar : Good to abundant 

 growth. Vegetative mycelium heavy, 

 superficially spreading, folded, glossy 

 surface, white to cream-colored, later 

 sulfur-yellow to yellowish-graj^ with 

 golden to light orange reverse. Soluble 

 pigment of the same color. Aerial myce- 

 lium scant, thin, white or absent. 



Glucose agar: Good growth. Vegeta- 

 tive mycelium superficially spreading, 

 surface granulated, cream-colored to 

 straw-yellow, later dull chrome-yellow to 

 brownish-orange. Aerial mycelium thin, 

 smooth, dusty, white to pale yellowish- 

 gray, after 1 or 2 weeks more or less 

 abundantly interspersed with small, 

 moist, dark violet-gray to brownish 

 patches which gradually spread over the 

 whole surface. Light yellow soluble 

 pigment. 



Potato : Fair growth. Vegetative my- 

 celium raised, wrinkled, cream-colored, 

 later yellowish-gray to dull brownish. 

 Aerial mycelium absent or trace of white. 



Milk: Completel}^ digested in 3 to 4 

 weeks at 30°C without any previous co- 

 agulation. The reaction' becomes faintly 

 acid (pH 6.0 or less) . 



Nitrates not reduced with sucrose as 

 source of energy. 



Sucrose is inverted. 



