108 ACTINOMYCETES AS ANTAGONISTS 



culture against living bacteria suggested that the same substance is con- 

 cerned in both cases. The bacteria were therefore divided (970), on 

 the basis of their relation to actinomycetin, into three groups: 



Bacteria that were lysed by the culture filtrate; these included pneumo- 

 cocci and hemolytic streptococci 



Bacteria that were not dissolved even by the most active soluble sub- 

 stance, but which were depressed by the mycelium of the living ac- 

 tinomyces; these comprised various sarcinae and fluorescens types 



Bacteria that were not acted upon by either the living culture or the 

 actinomycetin preparation ; these included the colon-typhoid and the 

 pyocyaneus groups, though when the latter were killed by heat or 

 inactivated by radium emanations, as in the case of E. colt, or were 

 placed under conditions unfavorable to multiplication, they were dis- 

 solved by the lytic substance. 



The first detailed survey of the distribution of antagonistic organisms 

 among actinomycetes was made by a group of Russian investigators. 

 According to Borodulina (80), actinomycetes are able to antagonize 

 various spore-forming bacteria and to bring about the lysis of their liv- 

 ing cells. A thermostable substance was produced on agar media. The 

 activity of this substance was greatly reduced at an alkaline reaction, 

 whereas an acid reaction favored it. When B. mycoides and an antago- 

 nist were inoculated simultaneously into peptone media, no inhibitive 

 effect was obtained, because the bacterium changed the reaction of the 

 medium to alkaline, thereby making conditions unfavorable for the 

 production of the antibiotic substance by the antagonist. When the an- 

 tagonist was first allowed to develop in the medium, before the bac- 

 terium was inoculated, a strong antagonistic effect resulted, which led 

 to the elongation of the vegetative cells of B. mycoides; this was due to 

 a delay in fission and was accompanied by the suppression of spore 

 formation. 



Krassilnikov and Koreniako (504) found that many species of actino- 

 mycetes belonging to the genus Streftomyces but not Nocardia pro- 

 duced a substance that possessed a strong bactericidal action against a 

 large number of microorganisms. This substance was particularly active 

 against nocardias, mycobacteria, and micrococci j it was less active upon 



