52 



THE ACTINOMYCETES, Vol. II 



Figtjke 14. Orskov's motile Nocardia (Reproduced by courtesy of N. M. McClung] 



broth cultures, a thick, hard, orange to 

 brownish surface pellicle is formed. 

 Habitat: Soil. 



41. Nocardia petroleophila Hirsch and 

 Engel, 1950 (Hirsch, P. and Engel, H. Ber. 

 deut. bot. Gesell. 69: 441-454, 1956). 



Morphology: Grows slowly, but abun- 

 dantly on all mineral media, faster in a 

 petroleum atmosphere. It grows on certain 

 organic media, but does not produce any 

 aerial mycelium. Substrate mycelium breaks 

 up readily into rods; "involution cells" are 

 formed abundantly. Mycelial threads are 

 long, monopodially branched, 0.0 to 1.2 ju 

 in diameter, and contain "metachromatic 

 granules," readily stained with aqueous 

 methylene blue. Aerial hyphae have the 

 same diameter as the substrate hyphae, 

 little branched. Aerial mycelium wets with 

 difficulty. Xo aerial spores. Mycelial seg- 

 ments 1.2 to 5.0 by 1.2 to 12.5 m- Gram-posi- 

 tive; not acid-fast. 



Glucose-asparagine agar: Growth limited. 

 Colonies 0.3 mm, white, yellow reverse. 

 Aerial mycelium snow-white. Soluble pig- 

 ment none. 



Calcium malate agar: Growth limited. 



Nutrient agar: Growth limited. Colonies 

 whitish-yellow, 0.5 mm. Xo aerial mycelium. 



Starch agar: Growth limited. Aerial my- 

 celium snow-white; reverse yellowish. Starch 

 not hydrolyzed. 



Potato: Xo growth. 



Gelatin: Growth in form of microscopic 

 colonies. Xo liquefaction. Xo pigmentation. 



Milk: Growth limited, yellowish, dry. 

 Xo aerial mycelium. Xo coagulation; no pep- 

 tonization. 



Temperature: Optimum 25-28°C. Re- 

 sistant to drying. 



Salt concentration: Resistant to high 

 concentration. 



Habitat: Soil. 



42. Nocardia polychromogenes (Vallee, 

 1903) Waksman and Henrici, 1948 (Vallee, 

 H. Ann. inst. Pasteur 17: 288-292, 1903; 

 Jensen, II. Proc Linnean Soc. X.S. Wales 

 56: 79, 363, 1931). 



Morphology: Growth bright red, coral- 

 red to red-pink, of a doughy consistency, 

 later becoming leathery. Aerial mycelium 

 whitish with pink hue. Substrate growth 



