648 THE BIOCHEMISTRY OF B VITAMINS 



in antagonizing the inhibitory action of salicylic acid on Escherichia 

 coli. 105 Pantoyltaurine and certain pantoyltauramides have been found 

 to prevent the toxicity of salicylate but are only about 3 per cent as active 

 as pantoic acid. 106 It is suggested that the organism effects a partial 

 hydrolysis of the analogues forming pantoic acid which prevents the 

 toxicity of salicylic acid. 



DL-a-Amino-/?,/?-dimethyl-y-hydroxybutyric acid, which has been 

 termed pantonine, has been found to be as effective as DL-pantoic acid 

 in preventing the toxicity of salicylic acid for Escherichia coli, but was 

 inactive in replacing the pantoic acid or pantothenic acid requirement of 

 Acetobacter sub oxy dans. 107 



With Staphylococcus aureus, pantothenic acid prevented the toxicity 

 of low concentrations of salicylic acid in almost a competitive manner; 

 the anti-bacterial index varied only from 50,000 to 26,000 over a 16-fold 

 range of concentrations of pantothenic acid. 103 The vitamin was approxi- 

 mately 20,000 times as active as pantolactone. Ascorbic acid, pimelic acid, 

 and purine bases are reported to enhance the anti-salicylate action of 

 pantothenic acid and to permit ^-alanine, which is not otherwise effective, 

 to prevent the toxicity of the inhibitor. 108 The purine bases alone, particu- 

 larly guanine, prevent to some extent the bacteriostatic action of salicylic 

 acid. 



The toxicity of salicylic acid for a strain of Clostridium septicum is 

 reported to be related to the utilization of pantoic acid. 36 



A strain of Proteus morganii which required pantothenic acid or pantoic 

 acid for growth was unaffected by salicylic acid except at high concentra- 

 tions. 103 The toxicity of such high concentrations of the inhibitor was not 

 affected by pantothenic acid. 



The reproductive phase of Trypanosoma lewisi infection is prolonged 

 and the number of organisms is increased in rats by restricting panto- 

 thenic acid in the diet. Repeated administration of salicylic acid results 

 similarly in prolonging the reproduction phase and in an exalted para- 

 sitemia in the rats. 109 



Mandelic acid has an inhibitory action which is largely prevented by 

 pantothenic acid in some strains of Escherichia coli; 110 however, inhibi- 

 tion of growth of many strains is not obtained with mandelic acid except 

 at high concentrations, the effects of which are not prevented by panto- 

 thenic acid. 111 



Bibliography 



1. Williams, R. J., Truesdail, J. H.. Weinstock. H. H.. Jr., Rohrmann. E., Lyman, 



C. M., and McBurney, C. H., J. Am. Chem. Soc, 60, 2719 (1938). 



2. Mitchell, H. K., Weinstock, H. H., Jr., Snell, E. E., Stanberry, S. R., and Wil- 



liams, R. J., /. Am. Chem. Soc, 62, 1776 (1940). 



