NUTRITION OF MICRO-ORGANISMS 



15. NICOTINIC ACID IN THE NUTRITION 

 OF MICRO-ORGANISMS 



Nicotinic acid, like aneurine and riboflavine, is necessary for the 

 growth of certain micro-organisms, and was identified as a component 

 of " bios " by Schultz et al.^ 



Yeasts 



Yeasts do not require nicotinic acid to the same extent as they 

 require biotin, aneurine or pantothenic acid and, of seventy-one 

 kinds of yeasts tested by P. R. Burkholder,^ only nine required nico- 

 tinic acid. These were : Candida pseudotropicalis , Mycoderma valida, 

 M. vini, Saccharomyces fragilis, S. macedoniensis , Saccharomy codes 

 ludwigii, Schizosaccharomyces pombe, Torulopsis sphaerica, Zygosac- 

 charomyces marxianus and Z. lactis. A. S. Schultz and L. Atkin ^ 

 found that in addition Kloeckera brevis, Saccharomyces carlsbergensis 

 and Torula cremoris also required nicotinic acid. According to M. 

 Rogosa,* yeasts that ferment lactose require nicotinic acid, but yeasts 

 that do not ferment lactose do not require nicotinic acid, but the 

 above list contains representatives of both types. 



Yeasts were found to take up nicotinic acid added to the medium 

 on which they were grown. ^ 



Other Fungi 



P. R. Burkholder ^ examined a number of moulds, but none of 

 them required nicotinic acid. 



By exposing Neurospora crassa to X-rays and ultra-violet light, 

 D. Bonner and G. W. Beadle ^ obtained five different mutants. One 

 of these, when grown on nicotinic acid or nicotinamide, produced 

 two substances which exhibited nicotinic acid activity for one of the 

 other mutants. The substances formed were believed to be a hydroxy- 

 pyridine-carboxylic acid and its methylation product. 



One mutant of N. crassa was obtained which required tr^^ptophan 

 for growth and could not utilise indole, and another which grew with 

 either anthranilic acid, indole or tryptophan.^" When the latter 

 mutant was grown on a medium containing anthranilic acid with C^^ 

 in the side-chain, the nicotinic acid and tryptophan isolated from the 

 mould tissue contained no C^^, most of which was lost in the carbon 

 dioxide formed during growth (see also page 250). 



Bacteria 



Reference has already been made (page 226) to the use of Lacto- 

 bacillus arabinosus, L. helveticus and Leuconostoc mesenteroides in 



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