230 



THE ACTINOMYCETES, Vol. II 



Calcium malate agar: Growth colorless, 

 becoming yellowish. Aerial mycelium white. 

 No soluble pigment. 



Starch agar: Growth colorless to cream- 

 colored. Aerial mycelium white to pale 

 smoke-gray. No soluble pigment. 



Potato: Growth colorless. Aerial mycelium 

 white to smoke-gray; black, moist speckles. 

 No soluble pigment. 



Gelatin: Growth colorless. No aerial my- 

 celium. Xo soluble pigment. Moderate lique- 

 faction. 



Milk: Growth colorless. Aerial mycelium 

 white. No soluble pigment. Slow peptoniza- 

 tion. 



Nitrate reduction: Positive. 



Carbon utilization: n-xvlose, L-arabinose, 



w 



imy 



ttt% 



o 



B 



L-rhamnose, D-fructose, galactose, maltose, 

 lactose, D-mannitol, salicin utilized. Sucrose, 

 n-raffinose, inulin, D-sorbitol, dulcitol, i-ino- 

 sitol, sodium acetate, sodium citrate not uti- 

 lized. 



Antagonistic properties: Produces an anti- 

 biotic, acidomycin, said to be dihydrostrep- 

 tomycin (see also Imamura el al., 1956). 



Remarks: S. humidus is closely related to 

 S. hygroscopicus; growth of the latter on 

 agar media and on potato is cream-colored 

 to yellow to brown. 



124. Streptomyces hygroscopicus (Jensen, 

 1931) Waksman and Henrici, 1948 (Jensen, 

 H. L. Proc. Linnean Soc. N. S. Wales 56: 

 357-358, 1931). 



Morphology: Sporophores monopodially 

 branched, with narrow compact, sinistrorse 

 spirals, situated as dense clusters on the 

 main stems of the sporophores (Fig. 42). 

 Spores oval, 0.8 to 1.0 by 1.0 to 1.2 M , 

 smooth (PI. II nf, PI. IV Gb). 



Sucrose nitrate agar: Growth folded, 

 white to cream-colored, later sulfur-yellow 

 to yellowish-gray, with golden to light orange 

 reverse. Aerial mycelium scant, white to ash- 

 gray. Soluble pigment golden to light orange. 



Glucose-asparagine agar: Growth cream- 

 colored to straw-yellow, later dull chrome- 

 yellow to brownish-orange. Aerial mycelium 

 dusty white to pale yellowish-gray; later 

 small, moist, dark violet-gray to brownish 

 patches produced, gradually spreading over 

 the whole surface. Soluble pigment light 

 yellow. 



Nutrient agar: Growth wrinkled, cream- 

 colored, later yellowish-gray with yellowish- 

 brown reverse. Aerial mycelium scant, white. 



Potato: Growth raised, wrinkled, cream- 

 colored, later yellowish-gray to dull brown- 

 ish. Aerial mycelium absent or trace of 

 white. Melanin-negative. 



Gelatin: Liquefaction slow. No soluble 

 pigment. 



Milk: Xo coagulation; positive peptoniza- 



