r. II A r T K H 1 2 



Prodiiclioii of Vitamins and Other 

 Growth Factors 



\'ari()us actinomycetes and their meta- 

 bolic products exert a favorable effect upon 

 the growth of lower forms of life, including 

 fungi and other microorganisms, and upon 

 higher forms of animal and perhaps plant 

 life. This is due, partly at least, to their 

 ability to synthesize several vitamins. 



Herrick and Alexopoulos grew S. virido- 

 chromogenes in a liquid medium, then filtered 

 the culture and autoclaved it. The fungus 

 Sfereum gausapatum inoculated upon this 

 medium produced a heavier growth than 

 usually obtained on sterile media. Even more 

 striking results were obtained when Phyco- 

 myces blakesleeanus was used as the test 

 organism; since this culture is used in as- 

 saying for the presence of thiamine, the con- 

 clusion was reached that actinomycetes 

 produce this vitamin. In a further study of a 

 number of cultures of actinomycetes, it was 

 demonstrated that all were able to produce 

 thiamine or its intermediate or precursor. 



Mackinnon observed that various strains 

 of S. albus have a marked stimulating effect 

 upon the growth of Trichophyton discoides. 

 This effect was comparable to that exerted 

 by the presence of thiamine. The same effect 

 was obtained when P. blakesleeanus was 

 inoculated on a synthetic medium in which 

 the streptomyces had previously been grown. 

 Filtered cultures of *S. albiis added to syn- 

 thetic media had the same effect upon the 

 growth of thiamino-nMiuiring organisms. 



The formation by ^S. griseus of a growth 

 factor for Leuconostoc citrovorum was demon- 

 strated by Emery et al. (1950). This factor 

 was not identical with either B12 or B13 . 

 This factor had no activity upon pernicious 

 anaemia, but possessed leucocyte-stimulat- 

 ing activity. 



The production of carotenoids by actino- 

 mycetes has also been demonstrated. Pro- 

 tiva has shown that certain actinomycetes 

 are able to produce riboflavin and fiavopro- 

 tein in synthetic media. 



Formation of Vitamin B12 



The announcement, in 1948, by Rickes et 

 al. that certain actinomycetes are able to 

 produce vitamin B12 resulted in much in- 

 terest in the commercial possibilities of these 

 organisms as sources of this vitamin. It has 

 now been established that numerous actino- 

 mycetes are able to produce this \-itamin if 

 cobalt salts are added to the media to serve 

 as precursors. The production of B12 can 

 be measured by microbiological assays. Var- 

 ious strains of S. griseus, including the 

 streptomycin- and grisein-producing forms, 

 and \'arious Streptomyces species, such as 

 S. fradiae and *S'. aureofaciens, are able to 

 produce some vitamin B12 without affecting 

 the yields of the corresponding antibiotic 

 substance. Certain nonantibiotic-producing 

 actinomycetes, like S. olivaceus, were also 



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