FAMILY STREPTOMYCETACEAE 



951 



Strongly diastatic. 



Scant growth on cellulose . 



Starch is hj^drolyzed. 



Aerobic. 



Optimum temperature 25°C. 



Habitat : Soil. 



41. Streptomyces cacaoi (Waksman) 

 comb. 710V. (Actinomyces cacaoi Waks- 

 man, in Bunting, Ann. Appl. Biol., 19, 

 1932, 515.) Named for the chocolate 

 tree {Theohroma cacao). 



Long aerial mycelium with considerable 

 spiral formation ; the spirals are long and 

 open, not compact. 



Gelatin : Flocculent growth. Xo aerial 

 mycelium. Rapid liquefaction. No pig- 

 ment production. 



Nutrient agar: Brown-colored growth 

 covered with tiny patches of ivory- 

 colored aerial mycelium. 



Glucose agar: Thin yellowish growth, 

 later turning reddish-brown; no soluble 

 pigment; light gray to mouse-gray myce- 

 lium, with white edge. Typical odor 

 of streptomyces. 



Czapek's agar : Same as on glucose agar. 



Potato : Abundant brownish growth 

 with white to mouse-gray aerial myce- 

 lium. 



Biochemical characteristics : Strong 

 proteolytic enzymes acting on casein and 

 gelatin ; strong diastatic action, no sugar 

 or dextrin left in 1 per cent starch solu- 

 tion after a few days. Limited reduction 

 of nitrate. 



Source : Three strains isolated from 

 cacao beans in Nigeria. There were 

 slight differences among the three strains ; 

 the above description is of Strain L 



42. Streptomyces novaecaesareae nom. 

 7tov. (Actinomyces violaceus-caeseri \Ya.ks- 

 man and Curtis, Soil Science, 1, 1916, 

 111.) From Nova Caesarea, Latin name 

 for the State of New Jersey. 



Filaments with both straight and spiral 

 aerial hyphae ; spirals dextrorse. Conidia 

 oval to elongate. 



Gelatin stab : Small, cream-colored sur- 

 face colonies with slow liquefaction. 



Synthetic agar : Growth gray, becoming 

 bluish, glossy, much wrinkled. Aerial 

 mycelium appears late; white. 



Starch agar: Restricted, circular, blue- 

 ish- violet colonies. 



Glucose agar : Restricted, gray growth, 

 becoming red. 



Plain agar: Thin, cream-colored 

 growth . 



Glucose broth: Fine, colorless, flakj- 

 sediment . 



Litmus milk: Gray ring; coagulated; 

 slow peptonization, becoming faintlj' 

 alkaline. 



Potato : Growth cream-colored, 

 wrinkled, turning yellowish. 



Nitrites produced from nitrates. 



Soluble purple pigment formed. 



Starch is hydrolyzed. 



Aerobic. 



Optimum temperature 37 °C. 



Source : Isolated once from upland 

 California soil. 



Habitat: Soil. 



43. Streptomyces exfoliatus (Waks- 

 man and Curtis) comb. nov. (Actino- 

 myces exfoliatus Waksman and Curtis, 

 Soil Science, 1, 1916, 116.) From Latin, 

 stripped of foliage. 



Slightly wavy filaments with tendency 

 to form spirals. Conidia oval, 1.0 to 

 1.5 by 1.2 to 1.8 microns. 



Gelatin stab : Cream-colored surface 

 growth. Liquefied. 



Synthetic agar : Growth colorless, be- 

 coming brown, smooth, glossy. Aerial 

 mycelium in white patches over surface. 



Starch agar: Restricted, gray growth, 

 becoming brown. 



Plain agar: Grows only in depth of 

 medium. 



Glucose broth: Small, grayish colonies 

 in depth. 



Litmus milk ; Cream-colored ring, soft 

 coagulum in 12 days ; slow peptonization, 

 becoming strongly alkaline. 



Potato : Growth somewhat wrinkled, 

 gray, becoming brown. 



Nitrites produced from nitrates. 



Brown, soluble pigment formed. 



