INTESTINAL SYNTHESIS 



It is possible that the results of intestinal synthesis have been 

 noted previously without the real explanation having been appreciated. 

 F. M. Meyers/^ for example, reported that healthy Javanese excreted 

 from o to 63 /xg. of aneurine per day compared with 40 to 3000 fig. for 

 the inhabitants of temperate climates. He concluded that a chronic 

 low vitamin B^ intake may produce an adaptation of the body. Might 

 it not rather be that the needs of the body were being met in such 

 instances by the bacteria of the gut ? 



A little information is available concerning the effect of certain 

 factors on faecal excretion. Increased amounts of aneurine, for 

 example, were excreted in the faeces of humans when large amounts 

 of plant fibre were ingested,^ ^ although no change occurred in the 

 faecal excretion on altering the carbohydrate : fat ratio. ^^ The nature 

 of the carbohydrate may also be a factor affecting the bacterial syn- 

 thesis of aneurine, for Schweigert et al.^^ observed that the amount of 

 aneurine excreted in the urine increased when the sucrose in the diet 

 was replaced by lactose. Feeding live yeast stimulated bacterial 

 synthesis, and Parsons et al}^ found that compressed bakers' yeast 

 increased the faecal excretion in humans ; at the same time the urinary 

 excretion was reduced, showing that the vitamin B^ in the yeast was 

 not being absorbed. Better absorption was obtained after the yeast 

 had been boiled with water. A similar result was obtained with 

 rats. 21 



Of considerable interest in relation to bacterial synthesis in the 

 intestine are the results obtained by R. C. Thompson, 22 who found 

 that the intestinal micro-organism B. proteus vulgaris synthesised inter 

 alia aneurine, and by P. R. Burkholder and I. McVeigh,^^ who found 

 that aneurine was also synthesised on S5mthetic media by the intestinal 

 organisms, Escherichia coli, Bacillus lactis aerogenes, B. mesentericus, 

 B. vulgatus and B. faecalis alcaligenes. 



Synthesis of Aneurine in the Rumen 



Closely related to the phenomenon of bacterial synthesis in the 

 intestine of man is that of bacterial synthesis in the rumen of rumin- 

 ants. As already noted, Theiler et al.,\ in 1915, observed that rumin- 

 ants could be maintained on diets low in certain vitamins, and their 

 results were confirmed by Bechdel et al.^ Several years later, Wegner 

 et al.^^ and Hunt et al^^ found that the rumen contents of a calf, 

 obtained by means of a fistula, had a higher vitamin B^ content than 

 the diet. L. W. McElroy and H. Goss ^s reported a value of 7 /xg. 

 per g. for the concentration of aneurine in the dried nmien and retic- 

 ulum contents of a sheep that had been fed on a diet containing 

 only 0-4 /Ltg. per g. of the vitamin. Xhey concluded that the vitamin 



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