SUBSTANCES PRODUCED BY ACTINOMYCETES 171 



and other microorganisms still remains to be determined. Toxoflavin, 

 formed by Bacterium cocovenenanSy 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 (908, 909). 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 



The antibacterial substances produced by actinomycetes can be di- 

 vided into three groups : 



Water-soluble and alcohol-insoluble compounds of the protein type, in- 

 cluding actinomycetin (346, 347, 971-973), micromonosporin, and 

 the compounds of the lysozyme type (507) 



Ether-soluble and alcohol-soluble pigmented compounds, including ac- 

 tinomycin 



Basic substances, soluble or insoluble in ether and soluble in aqueous or al- 

 cohol acid solution, including streptothricin, streptomycin, and pro- 

 actinomycin 



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

 stance produced by only a few organisms, notably S. antibiotkus. The 

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

 The residue is evaporated and separated (946) into two fractions: 

 A, soluble in ether and in alcohol but not in petrol ether, giving a clear 

 yellow-colored solution when diluted with water j B, soluble in ether 

 and petrol ether, soluble with difficulty in alcohol, and giving a turbid 

 suspension with water. Actinomycin A is bright redj it possesses ex- 

 tremely high bacteriostatic properties but is rather slowly bactericidal. 

 Actinomycin B is colorless j it has comparatively little bacteriostatic 

 action but possesses strong bactericidal properties. Despite the fact that 

 the organism produces a dark-brown pigment on organic media, actino- 

 mycin does not possess the enzymatic properties of a tyrosinase. 



The purification of actinomycin A 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, 



