SERIES AND SPECIES OF GENUS STREPT0M1 ( SI 



i:;;; 



ture appear to be related to the Fradicu 

 series. Baldacci ei al. I L953) at firsl did nol 

 recognize this organism as representing a 

 distincl series, and apparently considered i1 

 as a member within the "roseus" series. 

 Later, however, Baldacci and Comaschi 

 ( 1956) gave it scries characteristics. 



Gause ei al. (1957) divided the Fradicu 

 series, on the t>asis of spiral formation, into 

 two subgroups: one, spiral-forming, com- 

 prising .1. roseoflavus; the other, nonspiral- 

 forming, comprising .1 . fradiat proper; other 

 species and varieties were included in both 

 subgroups. Most of the members of a new 

 series, designated as "fuscus," could also he 

 considered as members of the Fradiae series. 



Waksman and Scotti (1958) divided the 

 Fradiae series into three subgroups. These 

 were described briefly as follows: 



i. Substrate growth on synthetic media 

 thin, smooth, colorless, almost entirely lim- 

 ited to the surface of the medium; occasion- 

 ally colored orange-yellow. Aerial mycelium 

 light pink, seashell-pink, or salmon-colored. 

 Some strains produced little if any growth 

 on synthetic media. Bes1 sporulat ion took 

 place on potato agar and on glucose-aspara- 

 gine agar. On organic media, growth was 

 smooth to wrinkled, yellowish or orange- 

 yellow to orange-brown; aerial mycelium, if 

 present, was white to seashell-pink. On cer- 

 tain media, a soluble, pink to salmon-colored 

 pigment was produced. Morphologically, all 

 strains formed a straight aerial mycelium; 

 some cultures, however, were able to form 

 hooks and loops, and even occasional spirals, 

 on certain media. These strains were con- 

 sidered as representing typical S. fradiae 

 proper. 



I la. On synthetic media, substrate growth 

 thin, colorless, limited almost entirely to the 

 surface of the medium; aerial mycelium 

 white. On organic media, growth cream- 

 colored to yellowish; aerial mycelium thin, 

 white to grayish-white. On yeast-glucose 

 agar, growth orange to brownish to greenish; 



aerial mycelium white. Abundant spirals 

 were found in the aerial mycelium. 



tlb. < >n synthetic media, growth very 

 poor. < >n organic media, growth generally 

 pool'; growth best on yeast-glucose agar. 

 Xo aerial mycelium was formed. 



A detailed characterizati if subgroup I 



is given in Table is. Among the other species 

 apparently closely related to this section is 

 S. kanamyceticus (Okami and Qme- 

 zawa l. 



The following species may lie included in 

 the Fradiae series: S. fradiae, S. luridus, S. 

 albosporeus, perhaps also S. roseus and S. 

 fuscus. 



A III. Series Griseus 



< 'haracteristic I 'mix rtu s 



a. Sporophores straight, produced in tufts. 

 Spores oval; surface smooth. 



b. Growth colorless to olive-buff. Aerial 

 mycelium water-green to grass-green to gray. 



c. Melanin-negative. 



d. Strong proteolytic activities. Produce :i 

 variety of antibiotics. 



An organism, under the name of A . grist us, 

 was first isolated and described by Krainsky 

 iu 1914. Its substrate growth on artificial 

 media was colorless; only a small amount of 

 yellowish soluble pigment was produced. The 

 aerial mycelium was of a green-gray color 

 on both organic and synthetic media. When 

 the concentration of nitrogen in the medium 

 was increased to 0.005 per cent, the aerial 

 mycelium became white. The culture was 

 only weakly proteolytic. 



Soon afterward, in 1915, Waksman and 

 Curtis isolated several cultures of what ap- 

 peared to be the same organism, the com- 

 parison with krainsky'- description being 

 based primarily on the color of the aerial 

 mycelium. Since this work was done during 

 the years of World War I, Krainsky's 

 original strain could not be obtained for com- 

 parative studies. The new culture was des- 



