892 XIV. NUTRITIONAL VALUE OP FATS 



(expressed in ng. of biotin per mg. of fatty acid) were obtained : oleic acid, 

 6.0; methyl oleate, 3.2; oleic acid amide, 6.3; oleyl alcohol, less than 

 0.05; elaidic acid, 1.0; vaccenic acid, 1.2; dihydroxystearic acid (94°C.), 

 less than 0.05: and dihydroxystearic acid (130.7°C.), less than 0.05. 

 Linoleic acid (12-octadecadienoic acid) also possesses a high biotin-like 

 activity in promoting the growth of Clostridium hutyricum and of Strepto- 

 coccus faecalis,^^'' and CI. sporogenesr^^ However, some workers found 

 that its activity was lower than that of oleic acid, and that it was inhibitory 

 at high concentrations. -^^■-''^•-■*'''-^'''-^^ Linolenic acid (9,12,15-octade- 

 catrienoic acid) is likewise effective in stimulating bacterial 

 gro^vt.h,-^^■-^^•-•*^•2■'^ but its potency was found to be only a fraction of that of 

 oleic acid.^^^ 



The ability of unsaturated fatty acids to substitute for biotin is not 

 limited to the octadecenoic acid. Thus, palmitoleic acid (7-hexadecenoic 

 acid) was shown by Hassinen, Durbin, and Bernhart,-^- as well as by 

 Boughton and Pollock, -^^-^^ and by Pollock, Howard, and Boughton,-*^ 

 to have a stimulatory capacity approximating that of oleic acid. In the 

 case of L. arabinosus, hexadecenoic acid was able to stimulate the growth of 

 bacteria in a manner similar to that of oleic acid, while the growth stimula- 

 tion of Lactobacillus bifidus occurred only at a low concentration.^^- How- 

 ever, Boughton and Pollock alone-"** and with Howard-^^-^*'' were able to 

 demonstrate positive stimulation of an oleic acid-requiring diphtheroid 

 species of Corynehacterium ("Q") by cis- and irans-palmitoleic acid, as 

 well as by the odd-carbon acids cis- and trans- heptadec-9-enoic acids. -"^^ 



Not all unsaturated acids are active. Thus Boughton and Pollock^''* 

 reported negative results Avith the following acids: m-undec-9-enoic 

 acid; czs-undec-10-enoic acid; cis- and ^rans-myristoleic acid (9-tetrade- 

 cenoic acid); cis- and trans- gadoleic acid (9-eicosenoic acid).^*' Pollock, 

 Howard, and Boughton^"*® reported that erucic acid (m-13-docosenoic 

 acid), brassidic acid (<rans-l 2-docosenoic acid), Q:,i3-oleic acid and ricino- 

 leic acid (12-bydroxy-9-octadecenoic acid) were all quite inactive, although 

 Shull ft alr^'^ noted that ricinoleic acid exhibited activity in replacing biotin. 



d. The Effect of Saturated Acids upon Bacterial Growth. In contradis- 

 tinction to the activity of a number of unsaturated fatty acids which sub- 

 stitute for biotin as growth factors in bacterial cultures, the saturated fatty 

 acids have been found to be completely inactive when supplied alone. 

 This is true not only of the various even-chain carbon acids from Cs to 



261 F. W. Norris and K. J. Lynes, Biochem. J., 43, xlv-xlvi (1948). 

 ''"J. B. Hassinen, G. T. ]!)urbin, and F. W. Bernhart, Arch. Biochem., 25, 91-96 

 (1950). 



2" B. W. Boughton and M. R. Pollock. Biochem. J., 53, 261-265 (1953). 



