SERIES AND SPECIES OF GENUS STREPTOMl CES 



135 



ignated as .1. griseus Krainsky, although 



certain marked differences were observed 

 between the 1 WO isolates. 



Since no type culture of Krainsky's organ- 

 ism was available for comparison to any 

 investigator, all the subsequent descriptions 

 were based upon the Waksman and Curtis 

 culture, which was distributed to all collec- 

 tions in the world. 



In 1919, Waksman amended the descrip- 

 tion of Krainsky, as follows: "This organism 

 was isolated numerous times from the soil. 

 The name .1. griseus was used before by 

 Krainsky so that the description of the latter 

 is itself an amendment. Although this or- 

 ganism was originally identified with the 

 organism described by Krainsky under the 

 same name (from description only, wiihont 

 any actual comparison of cultures), this 

 identification should be, therefore, corrected. 

 The culture described here possesses a very 

 strong proteolytic power, while Krainsky 

 stated that his culture was not strong pro- 

 teolytically." 



The differences between the two cultures 

 can be briefly summarized as follows: .1. 

 griseus Krainsky produced a greenish-gray 

 to dark gray aerial mycelium, with a green- 

 ish-yellow soluble pigment in older cultures; 

 growth on potato was grayish, with white- 

 gray aerial mycelium; Krainsky never stud- 

 ied the morphology of his organism, except 

 for the shape (oval) and size of the spores. 

 .1. griseus Waksman and Curtis produced a 

 water-green to yellowish-green aerial myce- 

 lium; the sporophores were straight and were 

 formed in tuft-like masses; growth on potato 

 was yellowish, wrinkled, and without any 

 soluble pigment. 



■n spite i >f these differences, Waksman 

 hesitated at first to change the name of the 

 culture which he and Curtis first isolated. 

 This hesitation was due partly to the faci 

 that the organism was found to undergo 

 considerable variation upon continued cul- 

 tivation on artificial media. The substrate. 



the temperature of incubation, the length of 

 the incubation period, the amount and na- 

 ture of inoculum, all tended to exert an in- 

 fluence upon the morphological and cultural 

 characteristics of the organism. At one time 

 milk was clotted at 37°C in 2 days and then 

 peptonized; at another time, under the same 

 conditions, clotting of the milk required ."> 

 to (I days; at still another time, the milk 

 in some tubes was not clotted at all but was 

 rapidly peptonized. There were other recog- 

 nizable changes or variations. Drechsler, 

 studying the morphology of the Waksman 

 and Curtis cult tire, found that the aerial 

 mycelium showed proliferation of fertile 

 branches at moderately close intervals along 

 the axial hyphae, thus suggesting tuft for- 

 mation. This phenomenon alone would have 

 definitely indicated that the culture should 

 have been identified as a distinct species. 



In August 1943, in the laboratories of the 

 Department of Microbiology of the New 

 Jersey Agricultural Experiment Station, a 

 culture was isolated which produced the 

 highly important antibiotic designated as 

 streptomycin. Upon careful examination, 

 this culture was found to be similar to the 

 Actinomyces griseus described by Waksman 

 and Curtis in 1916. Since, in the meantime, 

 Waksman and Henrici had proposed thai the 

 generic name for the sporulating forms of 

 actinomycetes be changed from Actinomyces 

 to Streptomyces, the organism was named 

 Streptomyces griseus. This name has been 

 universally recognized, since 1944, as the 

 official one for the streptomycin-producing 

 organism, and has been so designated in nu- 

 merous oilier collections throughout the 

 world. A detailed description of this species 

 was published in 1948 (Waksman, Reilly 

 and Harris). 



Baldacci et al. ( 1954 I subjected the Grisi us 



series to a detailed study. They recognized 

 that this representative species had come to 

 the fore as a result of the important role 

 that it played in the production of antibi- 



