302 



THE ACTINOMYCETES, Vol. II 



\ 



Ago 



/ Agar 



^^: 



Figure 59. Four types of thermophilic actinomycetes (Reproduced from: Henssen, A. Arch. Mikro- 

 biol. 26:379, 1957). 



II. Long sterile aerial hyphae forming single 

 spores or chains of spores on side branches. 



1. Spores produced singly on simple or 

 branched sporophores. 



Thermomonospora Henssen 



2. Spores produced in two's or in longer 

 chains. 



Thermopolyspora Henssen 

 III. Single spores or chains of spores originate 

 directly from substrate mycelium, which 

 sometimes emerges from the agar surface 

 like an arch. 



Thermoactinomyces Tsiklinsky 

 B. Substrate mycelium septated. Spores formed 

 from both aerial and substrate mycelium. 

 Pseudonocardia Henssen 



Genus Streptotnyces 



XVI. Series Thermophilus 



Spores produced in chains, comparable 

 to the mesophilic species of Streptotnyces. 



I. Sporophores and chains of spores straight. 



a. Aerial mycelium white to light gray. 



2. Streptomyces rectus 



b. Aerial mycelium white; thermotolerant. 



1. Streptotnyces casei 

 II. Sporophores and chains of spores not si raight . 



1. Spore chains spiral -shaped. 



6. Streptomyces thermovulgaris 



2. Spore chains bent or curved. 



a. Aerial mycelium white to violet-gray. 



5. Streptomyces thermoviolaceus 



b. Aerial mycelium gray to lavender. 



4. Streptomyces thermofuscus 



c. Aerial mycelium white to light gray. 



3. Streptomyces thermodiastaticus 



1. Streptomyces casei (Bernstein and Mor- 

 ton, 1934) nov. comb. (Bernstein, A. and 

 Morton, H. E. J. Bacterid. 27: 625, 1934). 



Morphology: Sporophores straight, 0.5 to 

 0.7 p in diameter. 



Agar media: Growth colorless to white. 

 Aerial mycelium white. 



Gelatin: Liquefaction rapid. 



Milk: Positive coagulation and peptoniza- 

 tion. 



Starch: No hydrolysis. 



Nitrate reduction: None. 



Temperature: Optimum 40-60°C. Highly 

 resistant to higher temperatures and to dis- 

 infectants. Thermal death point 100°C. 



Habitat : Pasteurized cheese. 



Remarks: Krassilnikov (1949) placed this 



