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THE ACTINOMYCETES, Vol. II 



strate mycelium was taken as the basis for 

 the primary subdivision into sections, and 

 the color of the aerial mycelium for the 

 secondary subdivision into series. In the 

 systems used by Flaig and Kutzner (1954) 

 and by Kutzner (1956), the color of the 

 aerial mycelium was used in connection with 

 that of the substrate mycelium. The system 

 proposed by Yamaguchi and Saburi (1955) 

 was based principally upon the structure of 

 the sporophores, the color of the aerial my- 

 celium being utilized in a secondary sub- 

 division; in the final characterization, ad- 

 vantage was taken of the production of 

 soluble pigments. A similar system was used 

 by Shinobu (1958). Krassilnikov (1941, 

 1949), Hesseltine et al. (1954), Pridham et al. 

 (1958), Ettlinger et al. (1958), Mayama 

 (1959), and Nomi (1959) used morphological 

 criteria for the primary subdivision of the 

 genus. 



Each one of the above systems has in it- 

 self certain serious limitations. It is neces- 

 sary, therefore, to combine several prop- 

 erties in order to bring out the characterist ics 

 of the group or series, and especially those of 

 the species. 



Proposal System of Classification of (he Genus 

 Streptomyces into Groups or Series 



In presenting the following system, full 

 cognizance is taken of the criticisms to be 

 directed against it, especially thai the for- 

 mation of the melanin pigmenl is given 

 leading consideration, and that the pro- 

 duction of other soluble pigments as well as 

 of antibiotics is also given important con- 

 sideration. I have felt that because of my 

 own previous proposals, especially those in- 

 corporated in the various edit ions of Bergey's 

 .Manual, and my own interest in antibiotics, 

 the best I could do would be to modify this 

 system slightly. I hope that it will serve its 

 purpose in the future as it has done in the 

 past. The suggested series further broaden 

 my earlier concept of species-groups. In 



view of the fact, however, that it is desirable 

 for each group to be designated by a repre- 

 sentative species, it has been found neces- 

 sary, in some cases, to use a more recent, 

 well defined species rather than one used long 

 ago, for which no well established species is 

 now recognized. This is true, for example, of 

 the "chromogenes" series, which has been 

 designated as Phaeochromogenes, for which a 

 well recognized type culture is available. 



I believe that the system of classification 

 of the genus Streptomyces into series proposed 

 here is simple and convenient. The use of 

 ecological properties as a basis for the major 

 subdivision of the genus, as in the last edi- 

 tion of Bergey's Manual, has been discarded. 

 The thermophilic forms have been, for the 

 most part, transferred to other genera 

 (Chapter 11). The animal and plant isolates, 

 including both pathogens and saprophytes, 

 have been distributed throughout the genus, 

 among the various series, where they logi- 

 cally belong on the basis of their morphologi- 

 cal, cultural, and biochemical properties. 



Both morphological (structure of sporo- 

 phores) and cultural (color of aerial myce- 

 lium, melanin formation) characters are 

 combined in the major subdivision of the 

 genus into subgenera and into series. Each 

 series is subdivided, on the basis of specific 

 cultural and biochemical properties, into 

 species. Formation of soluble pigments, 

 pigmentation, and antibiotic production are 

 also frequently taken advantage of in char- 

 acterizing species. To identify a new culture 

 properly, it is important to consider not only 

 the series subdivision and species classifi- 

 cation, but also the detailed description of 

 each organism. Before it can be decided 

 whether a newly isolated culture is different 

 from one already described, a study should 

 also be made of the varieties within the 

 species previously created, as well as possible 

 mutations and variations within the culture. 



The names given for the various series are 



