118 



THE ACTINOMYCETES, Vol. I 



acids are utilized less readily, l^ut more 

 readily by some a&tinomycetes than by 

 others. Cellulose, chitin, sterols, and poly- 

 uronides can be utilized as sources of energy 

 and for cell synthesis by only certain or- 

 ganisms. Each one of these reactions is of 

 considerable biochemical interest. Some of 

 them have been utilized for identification of 

 specific organisms. The biochemical reac- 

 tions involved are discussed in detail in 

 Chapter 9. 



Salzmann (1901) found the following car- 

 bon sources most suitable for the growth of 

 actinomycetes {Streptothrix odorifera, prob- 

 ably a streptomyces) : various carbohydrates 

 and succinic, malic, tartaric, and citric 

 acids. Unsuitable sources were formic, ace- 



Table 20 



Carbon utilization by different actinomycetes 

 (Lieske) 



Carbon source 



Streptomyces Nocardia "^^[^Z".' 

 (No. 12) (No. 74) ^^y^%.^ 



* — = no growth; -|- = slight; -|-+ = nu)d- 

 erate; + + + = good; +-f--f-t- = oxcollent 

 growth. 



tic, propionic, butyric, htctic, benzoic, and 

 oxalic acids. 



Miinter (1913) demonstrated that various 

 carbohydrates, organic acids, and alcohols 

 are readily utilized as carbon sources by a 

 variety of aerobic long-hyphal organisms 

 now known to belong to the genus Strepto- 

 myces. 



Lieske (1921) compared the carbon uti- 

 lization of representatives of three groups: 

 (a) an aerobic, long-mycelial, sporulating 

 form (No. 12), probably a streptomyces; (b) 

 an aerobic, short-mycelial form (No. 74), 

 probably a nocardia, and (c) an anaerobic 

 form isolated from human actinomycosis 

 (Si), probably an actinomyces. One per cent 

 urea was used as a nitrogen source (only the 

 nocardia gave a trace of growth with urea 

 as the only carbon soiu'ce). The carbon 

 sources were used in 2 per cent concentra- 

 tion. The results are shown in Table 20. 

 Lieske used liquid media in his studies. He 

 fully recognized the fact that had other 

 media and additional cultures been used, 

 the results would no doubt have been dif- 

 ferent, especially on a quantitative basis. Li 

 agar media, for example, starch utilization 

 undoubtedly would have been different. 



In general, formic, oxalic, tartaric, ben- 

 zoic, and hippuric acids are unfavorable car- 

 bon sources for actinomycetes; under cer- 

 tain conditions of nutrition, however, some 

 of these can also be utilized by certain or- 

 ganisms. Acetic, lactic, citric, propionic, 

 pyruvic, succinic, and malic are good 

 sources. Ethyl alcohol and ethylene glycol, 

 as well as erythritol and dulcitol, are un- 

 favorable nutrients. Glycerol and mannitol 

 are, on the other hand, highly favorable 

 sources. Starch and certain hemicelluloses, 

 such as mannans, are excellent sources of 

 energy and carbon for a large number of 

 actinomycetes. Utilization of pentose and 

 hexosc phosphates has been studied by 

 Cochrane and Hawley. 



The significance of carl)()n utilization, in 



