94 BACTERIA AS ANTAGONISTS 



lated from other strains of B. subtiUs and named bacitracin (469). Still 

 another strain of B. sub tills isolated from soil enriched with M. tuber- 

 culosis yielded an antibiotic designated bacillin (284). This substance 

 is produced in manganese-containing media and is mostly found in the 

 cell-free filtrate of the culture. It is adsorbed on norite and eluted with 

 90 per cent ethyl alcohol, concentrated in vacuo and taken up in water. 

 It is active against both gram-positive and gram-negative bacteria. 

 Blood and certain other complex organic materials reduce or destroy 

 its activity. This is due to the presence of a substance which was desig- 

 nated antibacillin and which was found to be a peptide (1030). 



B. Ucheniformisy related to B. subtilis, was found (107) to produce 

 an effect against M. tuberculosis. The active substance was present in 

 the cells of the organism when grown on a synthetic medium. The cul- 

 ture was acidified to f¥L 2.5 and treated with 3 volumes of 95 per cent 

 ethanol. The coagulum was autoclaved and extracted on boiling with 

 0.5 volume of 0.4 per cent acetic acid for 45 minutes. The substance 

 had an activity against M. fhlei and S. aureus in i : 80,000 dilution, but 

 not against E. coU. M. tuberculosis hominis was inhibited in i : 20,000 

 dilution. Preparations of greater purity had an activity of i : 80,000/ 

 gm. The preparation, which was not very toxic to mice, was considered 

 as a mixture of several substances. 



Various other antibiotics have been reported for aerobic spore-form- 

 ing bacteria. Some of these substances are active against both gram- 

 positive and gram-negative bacteria. This is true, for example, of colis- 

 tatin (323a). 



Spore-forming bacteria are also able to produce antibiotics antago- 

 nistic to fungi. B. simplex was found (154) to be antagonistic to 

 Rhizoctonia solaniy an important plant pathogen. It produced a 

 thermostable agent that inhibited the growth and even caused the 

 death of the fungus. When the active substance was added to the soil 

 it controlled to some extent seed decay and damping-off disease of 

 cucumbers and peas. It was also active against bacteria (491). It is ad- 

 sorbed on norite and eluted with methyl alcohol 5 the latter is evapo- 

 rated in vacuo and the residue is taken up in water. This preparation 

 was designated as simplexin (287). 



B. mesentericus produced on artificial media an antibiotic that sup- 



