Skin lipids of the Florida indigo snake.

Abstract

AbstractCast skins of the Florida indigo snake (Drymarchon corais) yielded up to 8% chloroform: methanol‐extractable lipid, which was found to contain methyl ketones (20%), free secondary alcohols (15%), free primary alcohols (30%), free cholesterol (15%), free fatty acids (5%), and hydrocarbons (5%). The hydrocarbons appeared to be contaminants, because gas chromatography revealed a distribution characteristic of petroleum hydrocarbons. The methyl ketones were predominantly monounsaturated, with double bonds almost exclusively in the ω7 position. The structures of the secondary alcohols corresponded with the methyl ketones in regard to chain length distribution, location of the oxygen function in the 2 position, and the proportion and position of unsaturation. The primary alcohols were also predominantly straight, odd‐carbon, unsaturated compounds, with ω7 double bonds, but with chain lengths principally of 29 and 31 carbon atoms. The free fatty acids were mainly even‐carbon monounsaturated compounds of 16–20 carbon atoms with double bonds mainly in the Δ9‐position. Inspection of the lipid structures obtained from the Indigo snake suggest a biogenetic relationship whereby palmitic and palmitoleic acids are extended in chain length mainly to 32 and 34 carbonatom fatty acids. Retention or introduction of an oxygen function in the 3 position, followed by decarboxylation, could then yield structures corresponding with the methyl ketones and the related secondary alcohols. Insertion of an oxygen atom between carbons 2 and 3 of the methyl ketones, followed by loss of the two carbon atoms thereby isolated from the chain, would produce the series of odd‐carbon primary alcohols that were observed.