60 



FATTY ACID METABOLISM IN MICROORGANISMS 



300 



0.1 0.2 0.3 0.4 0.5 0.6 



Fig. 3.3. Fatty acid growth curves for L. casei. Abscissa, ^moles of 

 fatty acid per tube. Ordinate, Klett readings. 



functionally for c/^-vaccenic acid without undergoing chain 

 elongation. C/5-vaccenic and palmitoleic acids exhibit ap- 

 proximately equal growth-promoting activity in all three or- 

 ganisms. The ciW-tetradecenoic acid is somewhat less 

 effective than the Cie and Cis acids. The c/5-5-dodecenoic 

 acid exhibits a low order of activity, and the c/5-3-decenoic 

 acid is inactive. In view of Wakil's demonstration of the 

 role of biotin in saturated fatty acid biosynthesis (3), it is 

 of interest to note that aV7-tetradecenoic and cw-5-dodecen- 

 oic acids lose their ability to support growth for L. arabino- 

 sus when the bacteria used to inoculate the assay tubes are 

 subjected to extensive washing with 0.85% sodium chloride. 

 Biotin in amounts which failed to stimulate growth in ab- 



