DESCRIPTION OF SPIX'IKS OF STREPTOMYCES 



247 



cream to huff. Aerial mycelium white. No 

 soluble pigment. 



Nutrient agar: Growth moderate i<> good, 

 light brown. Aerial mycelium white. Solu- 

 ble pigment light brown. 



Starch agar: Growth moderate, thin; pale 

 olive-buff reverse. Aerial mycelium white. 

 No soluble pigment. Strong hydrolysis. 



Potato: Growth poor, waxy, wrinkled, 

 brown. Xo aerial mycelium. Soluble pig- 

 ment dark brown. 



Gelatin: Moderate surface growth. Aerial 

 mycelium white. Soluble pigment dark 

 brown. Xo liquefaction. 



Milk: Growth poor. Xo peptonization. 



Nitrate reduction: Negative. 



Production of H.S: Variable. 



Antagonistic properties: Produces a basic 

 antibiotic, netropsin. 



Remarks: Ettlinger et al. (1958) report 

 this organism to be melanin-negative. They 

 also consider S. cinnamomeus as closely re- 

 lated. 



102. Streptomyces niger (Rossi-Doria, 

 1891; emend. Krassilnikov, 1949) Waksman 

 (Rossi-Doria, E. Ann. igiene, 1: 399-438, 

 L891; Krassilnikov, X. A. Antinomy cetales. 

 [zvest. Akad. Nauk. SSSR, Moskau, p. 53, 

 1941). 



Morphology: Substrate growth of soft 

 consistency. Aerial mycelium produced only 

 on potato and synthetic agar. Sporophores 

 formed only seldom; open spirals, with 3 to 

 5 turns. Spores oval. 



Synthetic agar: Growth black. Aerial 

 mycelium dark gray. Xo soluble pigment. 



Nutrient agar: Growth black. Soluble 

 pigment brown. 



Gelatin: Slow liquefaction, in 30 days. 

 Melanin-negative (?). 



Milk: Xo change. 



Starch: No growth. 



Cellulose: No growth. 



Nitrate reduction: Negative. 



Sucrose: Xo inversion. 



Temperature: Optimum 25-30°C. 



Antagonistic properties: None. 



Remarks: This is a very unstable species 

 which dies out rapidly. It easily mutate.-, 

 giving rise to colorless cultures, producing 

 no aerial mycelium. It appears to be a 

 transition form, if not a true Nocardia. .1. 

 nigi r aromaticus Beresl new and .1 . nigrificans 

 (Kriiger) Wollenweber are listed by Krassil- 

 nikov as varieties of .1. niger. In view of the 

 formation of a soluble brown substance on 

 certain protein media, this organism may 

 belong to one of the chromogenic groups. 



163. Streptomyces nigrifaciens Waksman, 

 H)l 9 (Waksman, S. A. Soil Sci. 8: 107-168, 

 1919). 



Morphology: Sporophores branching with 

 tendency to curl; no true spirals. Spores 

 oval-shaped to elliptical. 



Sucrose nitrate agar: Growth colorless. 

 Aerial mycelium thin, gray. No soluble pig- 

 ment . 



Glucose-asparagine agar: Growth cream- 

 colored. Aerial mycelium mouse-gray with 

 white patches. 



Nutrient agar: Growth thin, cream-col- 

 ored. Aerial mycelium gray. Soluble pigment 

 brown. 



Starch agar: Growth cream-colored to 

 yellow. Aerial mycelium light buff-gray. 

 Hydrolysis imperfect. 



Egg media: Growth abundant, dark 

 brown. Xo aerial mycelium. Purplish zone 

 around growth. 



Potato: Growth gray becoming dark. 

 Aerial mycelium white, appearing late. 

 Soluble pigment black. 



Gelatin: Growth cream-colored to brown- 

 ish. Aerial mycelium white. Soluble pigment 

 brown. Liquefaction slow. 



Milk: Surface growth dark brown. Aerial 

 mycelium white. Coagulation and slow pep- 

 tonization. 



Nitrate reduction : Positive. 



Sucrose: No inversion. 



( Jellulose: Xo growth. 



Habitat: Pineapple soil in Hawaii. 



