NUTRITION OF MICRO-ORGANISMS 



Folic Acid Ck>ntent of Micro-organisms 



By microbiological assay with L. helveticus, Burkholder et al}^ 

 estimated the vitamin Be contents of autolysed and enzyme-digested 

 cultures of 82 strains of bacteria, 369 yeasts and 94 moulds. They 

 found chicken pancreas to be the best agent for releasing the vitamin 

 from its conjugate. No increase in the vitamin Be content of bacteria 

 and yeasts was obtained when xanthopterine was added to the culture 

 media. Many of the organisms produced considerable amounts of 

 vitamin Be conjugase. 



The amoimts of folic acid present in the five bacteria, Aerohacter 

 aerogenes, Serratia marcescens, Pseudomonas fluorescens, Proteus 

 vulgaris and Clostridium hutylicum ranged from 180 to 1200 molecules 

 per cell and the rate of synthesis from 0-25 to i-2 molecules per cell 

 per second. ^^ 



Folic Acid in Viruses 



The psittacosis virus can apparently synthesise pteroylglutamic 

 acid, since _/)-aminobenzoic acid and pteroic acid competitively antago- 

 nised the inhibition of growth of the virus by sulphadiazine and 

 pteroylglutamic acid antagonised the inhibition non-competitively.^^ 



References to Section 15 



1. J. H. Mueller and P. A. Miller, Proc. Soc. Exp. Biol. Med., 1942, 



49, 211, 648 ; /. Bact., 1942, 43, 763. 



2. G. W. Kidder and R. C. Fuller, Science, 1946, 104, 160. 



2.a. G. W. Kidder and V. C. Dewey, Proc. Nat. Acad. Sci., 1947, 33, 95. 



3. L. D. Wright and H. R. Skeggs, Proc. Soc. Exp. Biol. Med., 1944, 



55, 92. 



4. L. D. Wright, H. R. Skeggs and A. D. Welch, Fed. Proc, 1944, 3, 



88. 



5. A. K. Miller, Proc. Soc. Exp. Biol. Med., 1944, 57, 151. 

 5a. J. Greenberg, Proc. Soc. Exp. Biol. Med., 1949, 71, 306. 



6. B. L. Hutchings, E. L. R. Stokstad, N. Bohonos, N. H. Sloane 



and Y. SubbaRow, Ann. N. Y. Acad. Sci., 1946, 48, 265. 



7. A. K. Miller, /. Nutrition, 1945, 29, 143. 



8. H. P. Sarett, /. Biol. Chem., 1947, 171, 265. 



9. R. H. Nimmo-Smith, J. Lascelles and D. D. Woods, Brit. J. Exp. 



Path., 1948, 29, 264. 



10. L. Lemon, J. P. Sickels, B. L. Hutchings, M. E. Hultquist and 



J. M. Smith, Arch. Biochem., 1948, 19, 311. 



11. Merck & Co. Inc., B.P. 613992. 



12. P. R. Burkholder, I. McVeigh and K. Wilson, Arch. Biochem., 



1945. 7, 287. 



13. H. Mcllwain, Nature, 1946, 158, 898. 



14. H. P. Morgan, /. Exp. Med., 1948, 56, 285. 



511 



