Chemical characterization of ceramides isolated from a gliding marine bacterium Aureispira marina

Ceramides containing 2-hydroxy fatty acids were purified from a gliding marine bacterium Aureispira marina, and their chemical structure was investigated. The ceramide molecules contained 2-hydroxy-15-methyl-hexadecanoic acid and 2-hydroxy-15-methyl-hexadecenoic acid, and the double bond of the latter fatty acid was proved to be located between the positions C3 and C4. The major portion of these 2-hydroxy fatty acids was determined to have D-configuration (S-configuration) after diastereomeric derivatization. Three carbon skeletons were found in sphingosines from ceramides, ie (1) 1,3-dihydroxy-2-amino-4-octadecen, (2) 1,3-dihydroxy-2-amino-17-methyl-4-octadecen, and (3) 1,3-dihydroxy-2-amino-9-methyl-4-octadecen. Molecules with additional double bonds were found in sphingosines with structures 1 and 3. The presence of ceramides with these chemical characteristics would be a significant feature for the taxonomy of A. marina and related bacteria.