SUBSTANCES PRODUCED BY ACTINOMYCETES 189 



cribed to the presence of a heat-stable substance designated as antidotic 



(759). 



Diplococcin Is produced by certain lactic acid streptococci. It is a pro- 

 tein synthesized in the bacterial cells from the amino acids in the me- 

 dium, and is extracted with cold dilute acetic acid. The active protein is 

 precipitated by 60 per cent saturation with ammonium sulphate (701 ). 

 It is active against gram-positive cocci and Lactobacillus species, but not 

 against gram-negative bacteria. 



A thermostable substance was obtained (154) from B. simplex, an 

 organism capable of bringing about the destruction of various patho- 

 genic fungi. This antibiotic was later designated as simplexin. It was 

 produced by the bacterium grown both on synthetic and on organic 

 media. It can be adsorbed on activated charcoal and recovered from the 

 latter by the use of hot alcohol. 



To what extent substances of bacterial origin that are toxic to brain 

 tissues, like toxoflavin (C6H6N4O2), are also effective against bacteria 

 and other microorganisms still remains to be determined. Toxoflavin, 

 formed by Bacterium cocovenenans , is extracted from the culture satu- 

 rated with salt by means of chloroform j from this it is recovered by an 

 aqueous solution and purified (931, 932). 



Other bacterial toxins, like botulinus toxin, various amines and 

 purine bases, and numerous toxins produced by bacteria in living plant 

 and animal systems, are beyond the scope of this treatise. 



SUBSTANCES PRODUCED BY ACTINOMYCETES 



Actinom^ycin 



Actinomycin is an ether-soluble and alcohol-soluble pigmented sub- 

 stance produced by certain actinomycetes, notably S. antibioticus. The 

 culture medium is treated with ether, giving an orange-colored extract. 

 The residue is evaporated and treated with petrol ether (975). 



The purification of actinomycin was effected by chromatographic 

 adsorption, followed by fractionation of eluate. The orange-brown resi- 

 due left after treatment with petroleum ether was dissolved in benzene, 

 filtered, and allowed to pass through a tower packed with aluminum 

 oxide. On washing the tower with large amounts of benzene, a chro- 



