Effect of isomeric cis-octadecenoic acids on the growth of Leptospira interrogans serotype patoc.

Leptospira interrogans serotype patoc exhibited an increasing growth response when cultivated in media containing from 50 to 250 mug of sodium oleate per ml. Leptospiral growth in the presence of 250 mug of sodium oleate per ml was as good as that in the basal medium which contained 700 mug of oleic acid (in Tween 80) per ml. When positional isomers of oleic acid (9-octadecenoic acid) were present at a concentration of 200 mug/ml, the 2- and 8-isomers were not readily utilized, whereas the 3-, 4-, 6-, 11-, 15-, and 16-isomers gave a growth response equivalent to that of oleic acid, i.e., the 9-isomer. The 5-, 7-, 10-, 12-, 13-, 14-, and 17-isomers of octadecenoic acid induced growth responses which differed in magnitude but were intermediate to those of 2-18:1 and 3-18:1. When 200 mug of either 2- or 3-octadecenoic acid per ml was added in addition to 200 mug of 9-18:1 alone; 400 mug of 9-18:1 alone per ml inhibited growth of this organism. The growth response of leptospira to octadecenoic acids differed from that of mammalian cells, suggesting the presence of different enzymes in the two systems for the utilization of these substrates.