title: Unusual C24, C25, C26 and C27 polyunsaturated fatty acids of the marine sponge Microciona prolifera.
abstract: (1) Complete characterization of the fatty acids of the marine sponge Microciona prolifera, including double bond positional isomers, has identified 95 different acids in amounts of 0.1% or more. Trace amounts of 23 other acids were found. (2) 48% of the fatty acids present have C24--C28 chain lengths. These are all saturates, monoenes, dienes and trienes; the tetraene, pentaene and hexaene acids possess the usual C18--C22 carbon chains. The numerous C24--C28 acids present apparently originate within the sponge itself, indicating a highly active chain elongation system. (3) A new family of C24, C25, C26 and C27 polyunsaturated acids with isolated double bonds has been discovered. All contain delta 5,9 unsaturation. Specific acids identified were 5,9-24:2; 5,9-25:2; 5,9-26:2; 5,9,17-26:3; 5,9,19-26:3; 5,9,19-27:3 and 5,9,20-27:3. Biosynthetic pathways for such acids are proposed, based on intermediates found in our fatty acid analyses.
mesh_terms: D000818:Animals; D002849:Chromatography, Gas; D002855:Chromatography, Thin Layer; D005231:Fatty Acids, Unsaturated / Q000032:analysis*; D007536:Isomerism; D011161:Porifera / Q000032:analysis*
chemical_list: D005231:Fatty Acids, Unsaturated