0CAI 



LIST nf ILLUSTRATIONS 



Figure l.—Streptothrix of Ferdinand Cohn xx 



Figure 2.— First photograph of a species of Micromonospora (1899) . . 8 



Figure 3.— Structure of actinomyces mycehum 11 



Figure 4.— Typical growth of aerobic actinomycetes upon agar slants . . 16 



Figure 5 a-d.— Different types of branching of aerial mycelium of species 



of Streptomyces 18/21 



Figure 6.—Nocardia asteroides, grown on potato dextrose-beef extract agar 25 

 Figure 7.—Nocardia asteroides, grown on potato dextrose-beef extract agar 27 

 Figure 8.— Branching and sporulation of different strains of Nocardia . 29 

 Figure 9.— Sporulation of straight aerial hyphae of species of Streptomyces 39 

 Figure 10.— Streptomyces venezuelae, grown on potato dextrose-beef ex- 

 tract agar 44 



Figure 11.— Streptomyces sp., grown on potato dextrose-beef agar . . . 47 



Figure 12 a-d.— Different forms of sporulation of Micromonospora growing 



in composts, as shown by contact slide preparations 52/55 



Figure 13.— Details of sporulation and of spore germination by S. griseus 



as shown by electron microscope 56 



Figure 14.— Aerial mycelium of a Streptomyces, showing zonation or 



"fairy ring" formation 58 



Figure 15.— Electron micrograph of actinophage 61 



Figure 16.— Method of measuring actinophage concentration .... 64 

 Figure 17.— Variants of Streptomyces griseus growing on yeast extract- 

 glucose agar 70 



Figure 18.— Metabolic changes produced by S. lavendulae in aerated and 



stationary cultures 85 



Figure 19.— Metabolic changes produced by S. antibioticus in aerated and 



stationary cultures 88 



Figure 20.— Influence of temperature upon growth and carbon dioxide 



production by actinomycetes 92 



Figure 21.— Decomposition of hemicelluloses by actinomycetes, as meas- 

 ured by CO:; evolution 93 



Figure 22.— The use of the agar cross-streak method for testing the ability 



of actinomycetes to produce antibiotic substances 106 



Figure 23 a.— The use of M. tuherctdosis for testing production of anti- 

 biotic substances by actinomycetes 110 



Figure 23 b.— Inhibition of streptomycin-sensitive but not of streptomycin- 

 resistant strain Ill 



Figure 24.— Method of measuring antibacterial or antifungal potency of 



an antibiotic, by the agar streak method 113 



Figure 25. -Streptomycin-producing strain of S. griseus, showing vegeta- 

 tive and aerial mycelium 122 



Figure 26.— Method of isolation of streptomycin from metabolite solution 125 

 Figure 27.— Crystals of the calcium chloride double salt of streptomycin 127 

 Figure 28.— Metabolic changes produced in the medium by Streptomyces 



sp. 



128 



Figure 29.— The course of development of S. alhus and bacteriolytic activ- 

 ity of the culture filtrate, actinomycetin 130 



