VITAMINS 199 



species of Zygosaccharomyces (Lockhead andLanderkin, 1942). /S-Alanine 

 could be used in place of pantothenic acid for the deficient species of 

 Zygosaccharomyces. 



Growth of Penicillium digitatum is reported (Wooster and Cheldehn, 

 1945) to be stimulated by pantothenate, as well as by pyridoxine, biotin, 

 and thiamine. To our knowledge this is the only report of a filamentous 

 fungus isolated from nature being stimulated by the presence of this 

 vitamin. Tatum and Beadle (1945) reported a mutant of Neurospora 

 which was deficient for pantothenic acid. 



Specificity. As in the case of thiamine and inositol, the structure of 

 pantothenic acid is almost specific for activity. A hydroxypantothenic 

 acid synthesized by Mitchell et al. (1940) has a varying ability to replace 

 pantothenic acid for some organisms. The activity of this compound 

 for the Gebriide Mayer yeast was low as compared with pantothenic acid. 



Mode of action. Pantothenic acid was found to favor the accumula- 

 tion of glycogen by yeasts (Williams et al, 1936), and to increase markedly 

 the rate of carbon dioxide evolution by the pantothenic acid-deficient 

 Gebriide Mayer yeast (Pratt and Williams, 1939). More recent work 

 (Novelli and Lipmann, 1947) has show^n that pantothenic acid is phos- 

 phorylated and acts as a coenzyme. This enzyme system performs vari- 

 ous oxidations and acetylations in the cell. 



PYRIDOXINE 



Pyridoxine is also known as adermin or as vitamin Be. While inositol 

 and pantothenic acid were first investigated as growth factors for micro- 

 organisms, pyridoxine was discovered as a result of animal research. 

 This vitamin was isolated independently by five groups of workers in 

 1938 and was synthesized the next year. The structural formula is given 

 below : 



HO- 

 CHs- 



■^ n— CH2OH 



Pyridoxine 



Pyridoxine is quite soluble in water and is stable to acid and alkah but is 

 destroyed by light. 



Fungi deficient for pyridoxine. Partial or total deficiencies for this 

 vitamin have been reported for various species and strains of yeasts 

 (Eakin and Williams, 1939; Burkholder, 1943). Among these are Sac- 

 charomyces carlsbergensis var. mandshuricus Y-379, S. chodati Y-140, S. 

 oviformis, S. ludwigii, and Mycoderma valida Y-7. 



Leonian and Lilly (1942) found that the omission of either thiamine or 

 pyridoxine alone from the medium was without effect on 9 of the 10 strains 



