METABOLISM OF ACTINOMYCETES 



19 



dark pigment on tyrosin. Only some cultures of A. scabies 

 and to some extent two to three other chromogenic strains are 

 able to produce this pigment, indicating that only these species 

 are able to form the two enzymes necessary to transform tyrosin 

 into melanin. A detailed study of this question will be taken 

 up in a paper on the "Enzymes of actinomycetes." At present, 

 the fact can only be pointed out that when the actinomycetes 

 were grown on gelatin plus 1 per cent starch, to which HC1 and 

 KI had been added only those species that are able to produce a 



TABLE 3 

 The growth of actinomycetes on tyrosin and the production of a soluble pigment 



ORGANISM 



Control 



A. violaceus-ruber . . . . 



A. exfoliatus 



A. aureus 



A. viridochromogenus . 



scabies I 



scabies II 



scabies III 



205 



pheochromogenus . . 



SOLUBLE PIGMENT 



Bluish 









 Trace of brown 

 Deep brown 

 Pinkish 





 Greenish brown 

 Brownish 



P H 



6.8 

 6.2-6. 

 6.6 

 6.6 

 6.6 

 5.4 

 7.0 

 6.7 

 6.6 

 6.7 



* The figures have the same designation as in table 1. 



brown pigment on the gelatin, produced a purplish color; this 

 indicates that an oxidase is produced by those species that color 

 the cultures containing gelatin and other proteins brown, while 

 they may not be able to convert tyrosin into melanin. 



A more detailed study of pigment production by actino- 

 mycetes will be published later. Attention may be here called 

 to the fact that A. violaceus-ruber which produced a beautiful 

 red brown pigment changing to violet blue is a very active nitrite 

 forming organism; the part played by the nitrites in the syn- 

 thesis of the pigment may be important. 



Attention was called, in connection with table 1, to the fact 

 that ammonium salts and amides form a rather poor source of 

 nitrogen for most actinomycetes. Whether this is true only 

 with glycerol as a source of energy or also with glucose, one can 



