NUTRITION OF MICRO-ORGANISMS 



65. N. L. Edson, Biochem. J., 1947. 41, 145. 



66. F. H. Johnson and H. Eyring, /. Amer. Chem. Soc, 1944, 66, 



848. 



67. E. S. G. Barron and T. E. Friedemann, /. Biol. Chem., 1941, 137, 



593- 



68. F. Bernheim, M. L. C. Bernheim and M. D. Webster, ibid., 1935, 



110, 165. 



69. R. Kuhn and R. Strobele, Ber., 1937, '^^» 753- 



70. P. Karrer and H. Fritzsche, Helv. Chim. Acta, 1935, 18, 911. 



71. M. Heiman, Arch. Ophthal., 1942, 28, 493. 



72. A. Segalofi and A. Segaloff, Endocrin, 1944, 34, 346 ; K. Unna, 



H. O. Singher, C. J. Kensler, H. C. Taylor and C. P. Rhoads, 

 Proc. Soc. Exp. Biol. Med., 1944, 55, 254 ; H. O. Singher, C. J. 

 Kensler, H. C. Taylor, C. P. Rhoads and K. Unna, /. Biol. 

 Chem., 1944, 154, 79. 



73. W. Antopol and K. Unna, Cancer Res., 1942, 2, 694. 



16. RIBOFLAVINE IN THE NUTRITION OF 

 2VUCRO-ORGANISMS 



Yeasts and Other Fungi 



No yeast has been reported for which riboflavine is an essential 

 growth factor ^» "^^ ^ and, of seventeen moulds also examined, none 

 required riboflavine. Riboflavine is not, in fact, a constituent of 

 "bios " (see page 105). 



Yeasts and moulds appear to be capable of synthesising ribo- 

 flavine, some in astonishingly large amounts (see page 148). 



Bacteria 



Bacteria vary greatly in their requirements for riboflavine. Some, 

 such as Bacilhis proteus vulgaris, B. lactis aerogenes, B. mesentericus, 

 B. vulgatus, B. faecalis alcaligenes and Escherichia coli, are capable of 

 synthesising it,* and the significance of this synthesis in the animal 

 economy has already been discussed (see page 185). The tuberculosis 

 bacterium does not require riboflavine.*'^ Some bacteria, on the other 

 hand, are incapable of growth in the absence of riboflavine, but these 

 are very few in number. Lactobacillus helveticus (L. casei e) is the 

 best known of these and is the organism most commonly employed 

 for the microbiological assay of riboflavine (see page 157) ; the closely 

 related organism, L. arabinosus, does not require riboflavine. Other 

 bacteria for which riboflavine is essential are : Streptococcus mastiditis, 

 S. faecium, Bacterium bifidum, and Streptobacterium plantarum ; ^ 

 Bacillus Delbriickii, Streptobacterium casei, Leuconostoc Gayoni and 



203 



