SPECIES OF STREPTOMYCES 103 



113. Streptomyces thermofuscus (Waksman, Umbreit, and Cordon) 

 Waksman and Henrici. (Waksman, S. A., Umbreit, W. W., and Cordon, 

 T. C, Soil Sci., 47, 1939, 49.) 



Aerial mycelium: Hyphae spiral-shaped; conidia produced. 



Potato: Growth abundant, dark-colored; no aerial mycelium, or few white 

 patches, soluble pigment dark. 



Gelatin: Liquefaction. At 50°C, a grayish ring is produced and soluble 

 pigment is formed. At 28°C, growth with no soluble pigment. 



Milk: Proteolysis. 



Starch: Hydrolysis. 



Czapek's agar: At 28°C, growth poor, deep gray, with but little aerial 

 mycelium. At 50°C, growth dark to violet, with gray to lavender aerial 

 mycelium and soluble brown pigment. 



Temperature: Good growth at 50° and 60°C. Will grow at 65°C. Faint 

 growth at 28°C. 



Remarks: This species is distinguished from Streptomyces thermophilus 

 by the brown-colored aerial mycelium on synthetic media, spiral-shaped 

 hyphae, and ability to grow readily at 65°C. 



114. Streptomyces casei (Bernstein and Morton) comb. nov. (Bernstein, 

 A., and Morton, H. E., J. Bacterid., 27, 1934, 625.) 



Vegetative growth: Colorless to white. 



Aerial mycelium: White, 0.5-0.7/x; no spirals. 



Gelatin: Liquefaction complete. 



Milk: Coagulation and peptonization. 



Starch: No hydrolysis. 



Nitrate: No reduction. 



Temperature: Optimum 40°-60°C. Highly resistant to higher tempera- 

 tures and to disinfectants. Thermal death point 100°C. 



Habitat: Pasteurized cheese. 



Remarks: Krassilnikov places this culture in the same group with Acti- 

 nomyces invulnerabilis of Acosta and Rossi, the latter being even more re- 

 sistant to high temperatures and to disinfectants. 



115. Streptomyces clavifer (Millard and Burr) comb. nov. (Millard, 

 W. A., and Burr, S., Ann. Appl. Biol., IS, 1926, 580.) 



Vegetative growth: Yellow to yellow-orange; soluble pigment yellow- 

 brown. 



Aerial mycelium: Sporophores long, straight, some terminating in club- 

 shaped structures. Spores cylindrical, 1.5 by 1.0 /x. 



