IERIES AND SPECIES OF GENUS STREPTOMYCES 



123 



dassonvillei, Str. foersteri, Str. graminearum, 

 Str. ieucea, Str. lathridii, and Str. pyogenes. 

 Such a large conglomeration defeats com- 

 pletely the purpose of grouping, since the 

 above forms vary greatly morphologically, 

 culturally, and physiologically. 



A number of species can, however, be in- 

 cluded in this series. It is sufficienl to men- 

 tion S. albus, S. calvus, and S. niv< us. 



II. Series Cinereus 



( 'haracteristic Properties 



a. Sporophores straighl or spiral-shaped. 



h. Color of aerial mycelium white to 

 gray; occasionally dark humid stains or 

 gu1 tation drops. 



c. Growth usually colorless, occasionally 

 yellow to tan. 



d. Melanin-negative. 



When members of tins series form an 

 aerial mycelium, the color is characteristi- 

 cally gray. Although it may be white at 

 first, it changes to various shades of gray, 

 ranging from lighl gray to mouse-gray to 

 bluish-gray or even vinaceous-gray or black- 

 ish-gray. Frequently white spots are pro- 

 duced in the aerial mycelium. The substrate 

 growth is often colorless or gray, occasion- 

 ally becoming yellowish to huff-colored; it 

 is either opaque or somewhat slimy; the 

 reverse is usually colorless, occasionally 

 turning yellow to tan. It is melanin-nega- 

 tive. Occasionally a yellowish or brownish 

 soluble pigment may be produced. The 

 sporophores are straight, often formed in 

 clusters or tufts; they may also produce 

 spirals that are either open or compact. 



This series is widely distributed in nature. 

 It comprises, in addition to well described 

 species given here, a greal number of incom- 

 pletely described forms, as shown in Chapter 

 12. 



A variety of antibiotics have been found 

 to he produced by members of this series. 



Som, ( 'haracU ristic Specii s 



The following species may he tentatively 

 included in this series: S. craterifer, S. inter- 

 medius, S, parvullus, and S. c< lluhscu . 



< )ne may also include in this series various 

 organisms described by Kxassilnikov I L949), 

 including his emendation of A. griseus 

 Krainsky (not S. griseus Waksman), .1. 

 griseus variabilis, and .1. griseus zonatus. 

 Tin- is also true of some of the forms de- 

 scribed by Cause et <il. (1957) under such 

 names as .1. rubiginosus, .1. griseomycini, 

 .1. iverini, A. acrimycini, A. acrimycini var. 

 globosus, .1. atroolivaceus, and .1. griseoru- 

 bens. 



II. Sei 



Flai 



Characteristic Propertit 'S 



a. Sporophores Long, spiral-shaped; spores 

 spherical to oval. 



1). Aerial mycelium white to .may to 

 mouse-gray ; color of growth yellow to golden 

 yellow. 



c Melanin-negative. 



d. Yellowish-green to golden soluble pig- 

 ment may he excreted into the medium. 



e. Strongly proteolytic and antagonistic. 

 The Flams series includes a large number 



of organisms, widely distributed in nature. 

 The members of the series vary greatly in 

 some of their cultural, biochemical, and 

 morphological properties when grown on 

 artificial media. This group has been recog- 

 nized since 1891, when Rossi-Doria de- 

 scribed a cult ure under the name of Sh; pto- 

 thrix albido-flava. Another similar culture 

 was soon described by Gasperini (1892) as 

 Actinomyces albido-flavus. Sanfelice (1904 

 designated the second of his three groups as 

 Str. flava, comprising organisms isolated 

 from the air. Caminiti (1907) was inclined 

 to include in this group various pigmented 

 forms, such as Str. citrea and Str. chromo- 

 iji /hi. 



Numerous organisms belonging to the 



