Studies on the Metabolism of Fatty Acids in Leptospira: The Biosynthesis of Δ⁹‐ and Δ¹¹‐Monounsaturated Acids

When Leptospira canicola was grown in a synthetic medium in the presence of ¹⁴C‐labeled acetate, the acetate was readily oxidized and incorporated into non‐lipid components of the cells. Only very small amounts of ¹⁴C‐acetate were incorporated into long chain fatty acids. The effect of the addition, to the growth medium, of different long chain fatty acids, on the fatty acid composition of phosphatidylethanolamine and triglycerides of L. canicola was studied. When grown on palmitate, palmitic acid, cis‐Δ⁹‐ and cis‐Δ¹¹‐hexadecenoic acid were isolated. When grown on stearate, stearic, palmitic, oleic and cis‐Δ¹¹‐hexadecenoic acid were found. When grown on oleate the later was the major component of the cell's lipids. Phosphatidylethanolamine isolated from L. canicola which was grown on Tween, contained oleic acid at the α position and palmitic, stearic and 11‐hexadecenoic acid at the β position. When L. canicola was grown in the presence of [1‐¹⁴C]palmitate or [1‐¹⁴C]stearate the corresponding monounsaturated acids were also labeled. Oxidative decarboxylation of ¹⁴C‐labeled 11‐hexadecenoic acid isolated from L. canicola which was grown on Tween plus [1‐¹⁴C]‐palmitate indicated that the monoenoic acid was labeled exclusively at the carboxy‐carbon.