ESMOND E. SNELL 



TABLE I {Continued) 



C. A^-Acctylglucosamine Lactobacillus bijidus 

 glycosides 



D. D-Lactic acid (or other Lactobacillus casei 

 a-hydroxy acids) (mutant) 



E. /)-Hydroxybenzoic acid Escherichia coli (mutant) 



F. Various peptides Lactic acid bacteria 



G. Thymidine and mis- 

 cellaneous nucleosides 

 and nucleotides 



H. Coprogen 



and 



Ferrichrome 

 L Biopterin 



Lactic acid bacteria 



Pilobolus sp. 



C< Cf 



Crithidia 

 fasciculata 



Gyorgy et al., 1954 



(19a) 



Kuhn, 1952 (31) 



Camien and Dunn, 



1953 (9a) 



Davis, 1950 (12) 



Sprince and Woolley, 



1945 (77) 



Snell, 1945 (63) 



Kihara and Snell, 1952, 



1955(28) 



Hesseltine, Pidacks, 

 Whitehill, Bohonos, 

 Hutchings, and 

 Williams, 1952 (21a) 

 Neilands, 1952 (37a) 



Patterson, Broquist, 

 Albrecht, von Saltza, 

 and Stokstad, 1955 

 (38a) 



derivatives were the active substances, and a variety of chemical 

 treatments combined with microbiological testing showed that 

 partial oxidation of pyridoxine to an aldehyde, or its amination 

 to an amine, yielded highly active substances (62). Synthesis 

 (20) of the limited number of possible structures (62) divulged 

 the structures of two active compounds (formulas I and II), which 

 were named pyridoxal and pyridoxamine (20,62,70). 



CHO 



(I) Pyridoxal 



CH2NH2 



(II) Pyridoxamine 



This was the first instance in which one of the B-vitamins 

 had been shown to exist in more than a single simple (i.e.. 



92 



