Chapter III 



63 — 



Morphology 



production of specific transmissible phages. Repeated additions of a 

 filtrate of S. roseus to the culture of the organism resulted in the 

 development of a phage which gave a large number of plaques on solid 

 media inoculated with the actinomyces and inhibited the growth of the 

 organism in liquid media. Phages were also obtained from the patho- 



Table 5 : Cultural and physiological characteristics of the streptomycin-producing strain of 

 S. griseus and its inactive variant (395) : — 



Active strain 



Inactive variant 



1. Antibiotic activity . Produces streptomy- 

 cin in both shaken and stationary cul- 

 tures. 



2. Growth. Surface growth always heavily 

 sporulated; grayish-green aerial myce- 

 lium. 



3- Reaction. Medium always changes to 

 alkaline; pYi 7.5-8.5. 



4. Glucose. Glucose completely consumed 

 in 6-8 days in stationary cultures and 

 in 3-4 days in shaken cultures. 



5. hy sis in shaken cultures. Shaken cultures 

 produce very fine flocculant growth, 

 tending to lyse slowly after about 15 

 days. 



6. Lysis in stationary cultures. Surface pel- 

 licles stable; any submerged, flocculant 

 growth tends to lyse as the surface pel- 

 licle develops. 



7. Viscosity. Culture filtrate not showing 

 any viscosity. 



8. Keinoculation . Inoculation of cultures 

 with lysed inactive culture induces no 

 lysis or reduction in activity. 



9. Variation. Sporulating strain gives rise 

 to non-sporulating variants. 



10. Sensitivity to streptomycin. Very resist- 

 ant to this antibiotic. 



1. No streptomycin formed either in 

 shaken or stationary cultures. 



2. No sporulating aerial mycelium; scant 

 development of aerial hyphae with 

 slight tendency to form spores in some 

 old cultures. 



3- Reaction of medium at first .icid, pH 



50-6. 5; later becoming alkaline. 

 4. Glucose utilized more slowly. 



5- Cultures produce at first balls of growth 

 which change into the turbid, floccu- 

 lant type; rapid and complete lysis in 

 7-10 days. 



6. Stationary cultures produce no surface 

 growth but flocculant, submerged my- 

 celial growth which lyses slowly, only 

 after a month or longer. 



7. Culture filtrate becomes viscous during 

 or after lysis. 



8. Inoculation of cultures with spores of 

 active strain produces growth and anti- 

 biotic activity if some glucose remains. 



9. Asporogenous variants may reconvert 

 to active, sporogenous forms. 



10. Very sensitive to this antibiotic. 



genie organisms A. hovis and N. farcinica. A polyvalent phage was 

 obtained from one of the actinomycetes which was also active upon S. 

 scabies, thvs suggesting possible methods of combating potato scab. 

 The phenomena of phage production by actinomycetes was referred to 

 as "microbiophagy." These investigators were thus the first to empha- 

 size the existence of filterable and transmissible agents comparable to 

 bacteriophages, which were active upon actinomycetes. 



Krassilnikov and Koreniako (237) emphasized the resemblance 

 of the process of autolysis among actinomycetes to the action of phage 



