FAMILY III. STREPTOMYCETACEAE 



807 



Streptomyces poolensis and Streptoinyces 

 tiunuli belong to this group. 



Source: Isolated from a small, unruptured 

 potato scab. 



Habitat: Found in potatoes so far as 

 known. 



123. Streptomyces praecox (Millard 

 and Burr, 1926) Waksman, 1953. (Actino- 

 myces praecox Millard and Burr, Ann. App. 

 Biol., 13, 1926, 601; Waksman, in Waksman 

 and Lechevalier, Actinomj-cetes and Their 

 Antibiotics, Baltimore, 1953, 107.) 



prae'cox. L. adj. praecox premature, pre- 

 cocious. 



Vegetative growth: Raised, colorless. 



Aerial mycelium: Well developed, gray 

 with greenish tinge. Sporophores produce 

 open spirals. Spores spherical or ellipsoidal, 

 0.8 micron in diameter. 



Gelatin: Good growth. Abundant, white 

 aerial mycelium. Liquefaction. 



Agar: Thin, colorless growth. Aerial 

 mycelium thin, white. 



Sjmthetic agar: Thin, powdery growth. 

 Aerial mycelium white to olive-buff. 



Synthetic glucose agar: Flat growth with 

 radiating margins. Aerial mycelium white 

 to olive-colored. On cultivation, aerial 

 mycelium is only white. 



Starch agar: Thin, cream-colored growth. 

 Aerial mycelium abundant, white with 

 greenish tinge. 



Broth: Cream-colored surface pellicle. 

 Aerial mycelium thin, white. No soluble 

 pigment. 



Glycerol synthetic solution: Heavy sur- 

 face growth. Aerial mycelium abundant, 

 powder}', white. Pale yellow soluble pig- 

 ment. 



Glucose broth: Flocculated growth at 

 bottom and heavy, wrinkled growth at sur- 

 face. Aerial mycelium abundant, white. 



Milk: Cream-colored surface growth in 

 form of a ring. Aerial mycelium white. Ac- 

 tively coagulated; rapidly peptonized. 



Potato: Good, cream-colored to light 

 brown growth. Aerial mycelium white to 

 olive-buff. Plug olive-buff to drab. On culti- 

 vation, no soluble pigment produced. 



Starch is hydrolyzed. 



Tyrosinase reaction: Negative. 



Nitrate reduction variable. 



Odor: Very strong. 



Grows well at 37.5° C. 



Antagonistic properties: Represses 

 growth of Streptomyces scabies. 



Relationship to other species: Krassil- 

 nikov regards this species as being related 

 to Streptomyces griseus Krainsky. 



Source: Isolated from a large, knob-like, 

 unruptured potato scab. 



Habitat: Found in potatoes so far as 

 known. 



124. Streptomyces setonii (Millard and 

 Burr, 1926) Waksman, 1953. (Actinomyces 

 setonii Millard and Burr, Ann. Appl. Biol., 

 18, 1926, 601; Waksman, in Waksman and 

 Lechevalier, Actinomycetes and Their 

 Antibiotics, Baltimore, 1953, 107.) 



.se.to'ni.i. M.L. gen. noun setonii of Seton; 

 named for a person, Seton. 



Vegetative growth: Golden yellow on 

 synthetic media. 



Aerial mycelium: Well developed, cot- 

 tony, dark gray to dark olive. Sporophores 

 straight, forming few spirals. Spores ellip- 

 soidal, 0.6 to 0.8 by 0.85 micron. 



Gelatin: Gray surface growth covered 

 with white aerial mycelium. Soluble brown- 

 ish pigment. Rapid liquefaction. 



Agar: Good, colorless growth covered 

 with white, smooth aerial mycelium. Soluble 

 brownish pigment. 



Sjmthetic agar: Abundant, smooth 

 growth. Aerial mycelium covering the whole 

 surface, gray to olive-buff. Soluble, faint 

 yellowish pigment. 



Starch agar: Cream-colored growth. 

 Aerial mycelium patch}', white. 



Glucose agar: Good, lichenoid, gray to 

 brown growth. Aerial mycelium abundant, 

 white to olive-buff. Soluble, golden brown 

 pigment. 



Glycerol synthetic solution: Flak}', white 

 growth. Aerial mycelium abundant, olive- 

 buff. Soluble greenish pigment. 



Glucose broth: Growth on surface and in 

 liquid good. Aerial mycelium abundant, 

 olive-buff. Soluble, light golden brown pig- 

 ment. 



Milk: Good surface growth covered with 

 ring of white aerial mycelium. Coagulated, 

 followed by rapid digestion. 



Potato: Heavy, wrinkled growth covered 



