NUTRITION OF MICRO-ORGANISMS 



aneurine content. A large proportion of the aneurine present in the 

 yeast cells was in the form of cocarboxylase. Thus about 75 % of 

 aneurine added to a press-yeast fermenting molasses was converted 

 into cocarboxylase ; only 6 to 8 % remained in solution and 15 to 

 30 % of the total vitamin in the washed cells was free aneurine. 

 After two hours, the amount of aneurine in the yeast (on a dry solids 

 basis) was 152 /xg. per g. of glucose fermented ; the maximum amount, 

 306 fig. , was formed after eight hours. Increasing amounts of aneurine 

 were obtained as the temperature was increased to 30° C. Galactose 

 and maltose, but not lactose or xylose, stimulated the synthesis of 

 aneurine. 



Torula utilis, like brewers' yeast, converts aneurine into the 

 pyrophosphate ; the yield was lower when the culture was aerated. 

 The pyrimidine and thiazole halves of aneurine (5-hydroxyethyl-4- 

 methyl-thiazole and 4-amino-5-hydroxymethyl-2-methyl-pyrimidine) 

 were quantitatively utilised and converted into cocarboxylase. With 

 only one component present, little or no S3rnthesis of aneurine occurred. 

 Bakers' yeast, Oidium lactis, Endomyces vernalis and Aspergillus oryzae 

 also synthesise aneurine from its components. T. utilis, bakers' yeast, 

 and top and bottom brewers' yeast did not produce aneurine from 

 5-hydroxyethyl-4-methyl-thiazole when 4-hydroxy-2-methyl-pyrimi- 

 dine-5-acetic ester, 4-chloro-2-methyl-pyrimidine-5-acetic ester, 4- 

 amino-2-methyl-pyrimidine-5-acetamide or 4-amino-5-cyano-2-methyl- 

 pyrimidine were used as the pyrimidine component. Bottom yeast 

 failed to synthesise aneurine from 4-amino-5-aminomethyl-pyrimidine 

 or 4-amino-5-hydroxymethyl-2-methyl-pyTimidine, but bakers' yeast 

 and top yeast, like T. utilis, were able to utilise both 4-amino-5- 

 hydroxym ethyl - 2 - methyl - pyrimidine and 4 - amino-5 - aminomethyl - 

 2-methyl-pyrimidine for the synthesis of aneurine. 



Similar results were reported by van Lanen et al.,^^ who found that 

 yeasts grown on a medium rich in aneurine might contain up to 6 mg. 

 per g. of the vitamin. Aneurine was sjmthesised from the pyrimidine 

 and thiazole halves, the yields being 70 to 100 %. Contrary to the 

 findings of Fink and Just, the yields were found to be increased by 

 aeration. Resting cells synthesised some pyrimidine, but not much 

 thiazole. 



A reduced yield on aeration, however, was obtained by Sperber 

 et al}^ and by E. N. Odintzova.^* The latter found that Saccharomyces 

 spp., T. utilis and Endomyces magnusii in anaerobic culture took up 

 to I mg. of aneurine per g. of dried cells from the culture liquid, but 

 much less when grown aerobically. Sperber observed two stages in 

 the uptake of aneurine by yeast. The first stage was rapid and 

 appeared to coincide with the adsorption of the vitamin on the cell. 

 It was sensitive to salts ; sodium chloride, potassium chloride, sodium 



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