Description of 



Species of Streptomyces 



To make this guide complete, detailed descriptions are included of the 

 more important and officially recognized species of the genera Streptomyces, 

 Nocardia, and Micromonospora. Most of these have been isolated from soils, 

 composts, peats, and water basins; some have come from dust and food 

 materials. Those forms which were isolated from plant disease lesions may- 

 or may not be the causative agents of such diseases; they certainly should 

 be considered on a par with the soil-inhabiting forms. 



The cultures of actinomycetes that were isolated from diseased animals 

 or from human infections, especially the species of Streptomyces, cannot be 

 considered as the causative agents of the diseases, since their pathogenic 

 nature has, in the great majority of cases, not been established experimen- 

 tally. 



No detailed data are presented concerning literature references, syno- 

 nyms, incompletely described species, and specific natural habits. For such 

 information, the reader is referred to the latest edition of Bergey's Manual. 



1. Streptomyces alb us (Rossi Doria emend. Krainsky) Waksman 

 and Henrici (Rossi-Doria, T., Ann. 1st. Ig. Sper. Roma N. S., 1, 1894, 

 399-438). 



Vegetative growth : Hyphae branched, 1 n in diameter. 



Aerial mycelium: Abundant, white. Hyphae 1.3-1.7 /x in diameter, form- 

 ing coiled chains on lateral branches. Spores ellipsoidal. 



Nutrient agar: No aerial mycelium; chalky white deposit on old colonies. 



Glucose agar: Aerial mycelium gray becoming brownish. 



Potato: Growth folded cream-colored. Aerial mycelium white. 



Gelatin: Colonies gray, no soluble pigment. Liquefaction strong. 



Milk: Cream-colored surface ring. Aerial mycelium white. Rapid pep- 

 tonization of milk. 



Starch: Aerial mycelium white, covering the whole surface. Rapid hy- 

 drolysis in some cultures; others show no hydrolysis. 



Nutrient broth: Flaky growth on bottom with surface pellicle in old 

 cultures; aerial mycelium white. 



Nitrate: Reduction to nitrite. 



Calcium malate agar: Colonies covered in center with white aerial my- 

 celium. 



Odor: Earthy or musty. 



