144 ACTINOMYCETES 



These grow into a mycelium on a fresh substrate. Cells are gram-positive, 

 non-acid-fast. Colonies usually rough. Some are smooth, dry, powdery, or 

 dough-like in consistency. Part of mycelium grows into substrate. Colonies 

 pigmented bright red. Pigment not dissolved into medium, weakly soluble 

 in ether, alcohol, and acetic acid; soluble in chloroform; belongs to the 

 carotinoids. 



Aerial mycelium: None produced. 



Synthetic agar: Good typical growth. 



Nutrient agar: Poor growth. 



Potato: Good typical growth. 



Gelatin: No liquefaction. 



Milk: No change. 



Starch: No hydrolysis. 



Cellulose: No growth. 



Nutrient broth: Sediment and surface ring; medium clear. 



Nitrate: No reduction. 



Sucrose: No inversion. 



Paraffin: Good growth. 



Fats : Well assimilated. 



Source: Soil. 



Remarks: Grows well in high salt concentrations (5-10 per cent NaCl). 

 Krassilnikov considers Nocardia corallina, Nocardia salmonicolor and No- 

 cardia opaca as forms of Nocardia rubra. 



18. Nocardia coeliaca (Gray and Thornton) Waksman and Henrici. 

 (Gray, P., and Thornton, H., Centrbl. Bakt. II, 73, 1928, 88.) 



Mycelium: Short, curved, uneven-sided rods 0.8 by 5 m with occasional 

 filaments up to 10-12 n long, frequently beaded, occasionally swollen or 

 branched. Coccoid forms 0.8-1.2 n in diameter are common, especially in 

 older cultures. Stain readily. Not acid-fast, or occasionally slightly acid-fast. 

 Gram-positive. 



Nutrient agar: After 11 days, colonies less than 1 mm in diameter, round 

 or irregular, raised, white, resinous, edge irregular, burred. Deep colonies: 

 irregularly round or oval, edge slightly broken. Slant: filiform, convex, 

 white, rugose, resinous, edge undulate. 



Gelatin: After 12 days, irregular, raised, white, rugose, dull colonies, 

 edge entire. Deep colonies: irregular, smooth or slightly broken. Stab: 

 convoluted, buff -white to yellowish, dull; below surface the growth forms 

 many irregular hollow lobes, giving a glistening appearance, to a depth of 

 3-4 mm. 



Milk: Slightly alkaline after 5 to 7 days. 



Nutrient broth: Turbid. 



