CLASSIFICATION OF STREPTOMYCES SPECIES 



I .v. 



property 

 ither thai 



biotic as its major characterise 

 Hut this capacity is often a s1 fain 

 a specie.- characteristic. In view of the mu- 

 tational possibilities of such cultures and of 

 the marked effeet of composition of medium 

 and environmental factors upon the qualita- 

 tive nature and quantitative yield of the 

 antibiotic, one must consider such a prop- 

 erty, at best, as only a secondary character- 

 istic and avoid assigning to it an important 

 role in creating new species. 



Shinobu (1958b) emphasized again that 

 only synthetic media should he used for the 

 study of the sporulat ion of the aerial myce- 

 lium, notably spiral formation, in Strepto- 

 myces. In mosl species, the curvature of the 

 spiral is sinistrorse (counterclockwise); in a 

 few, dextrorse (clockwise). The diameter of 

 the spiral varies from 1.5 to 8.0 n and is not 

 a characteristic property, although it is fixed 

 for some species. As pointed out previously 

 (Chapter 4), three morphological groups 

 were recognized: (1) Those forming straight 

 or wavy aerial mycelium, (2) Spiral-forming 

 types, and (3) Verticil-forming types. 



Other criteria have been suggested. Some 

 of these may be utilized for supplementary 

 information in describing species and vari- 

 eties. A Subcommittee on Act inomycetes of 

 the Society of American Bacteriologists 

 (Gottlieb, L960) gave careful consideration 

 to the various criteria used in describing and 

 characterizing species of Streptomyces. They 

 came to the conclusion that morphology is 

 to be considered as one of the more impor- 

 tant criteria. Color of the aerial mycelium 

 and carbon utilization are also important. 

 Supplementary characteristics are provided 

 by the production of IIS, reduction of 

 nitrate, and gelatin liquefaction. Such cri- 

 teria as color of substrate growth and nitro- 

 gen utilization were not considered of suffi- 

 cient significance in describing new species. 



Many species, including a number of 

 newly isolated forms, have been placed in 

 Chapter b"» as incompletely described. ( Mhers 



have been listed as synonyms. Care ha- been 

 taken to avoid the creation of many new 

 varieties, unless it ha- been fully established 

 that such varieties have a sound morpho- 

 logical or cultural basis. Whether these 

 varieties should be raised to the status of 

 species remains to be determined by further 

 study. Any such attempt would automat- 

 ically lead to the temptation to create new 

 species out of mutants, which are unfortu- 

 nately altogether too common, whether 

 naturally occurring or artificially created. 

 for the time being, they may still be con- 

 sidered as varieties. 



Classification of (ienns Strt>i>(<ntiyces 



In proposing the present system of clas- 

 sification of the genus Streptomyces, the 

 following properties have been given the 

 greatest consideration: 



1. Morphology of sporulating bodies; size. 

 shape, and surface of spores. 



2. Color of aerial mycelium and of sub- 

 strate growth. 



3. Color of growth. 



4. Formation of soluble chromogenic or 

 melanoid pigments in proteinaceous media. 

 This property is used, together with micro- 

 morphology, for the major subdivisions of 

 the genus. 



o. Formation of soluble pigments in syn- 

 thetic media. 



('). Certain biochemical properties, notably 

 proteolysis, starch hydrolysis, nitrate reduc- 

 tion, formation of II_S, utilization of carbon 

 sources, and formation of specific anti- 

 biotics. 



This system is a modification of the one 

 originally used by Waksman and Curtis in 

 L916, variously changed in subsequent years 

 by Waksman and by Jensen, and used in 

 modified forms in the various edition- of 

 Bergey's Manual of Determinative Bac- 

 teriology. 



A. Sporophores straight, wavy, or spiral shaped; 

 no vert icils. 



