The structure of ceramide aminoethylphosphonate from the sea anemone, Metridium senile

Abstract 1. 1. Ceramide aminoethylphosphonate has been isolated from the sea anemone, Metridium senile (10 mg/g dry tissue weight or about 10% of the total lipids). 2. 2. The polar part after phospholipase hydrolysis was shown by gas chromatography and mass spectrometry to be exclusively phosphonoethylamine. 3. 3. The major fatty acid was palmitic acid (52 %), and 35 % were branched-chain acids. 21% had the methyl branch in position 14 and 13% the branch in position 15. From the methyl end the positions were 2, 3 and 4. 6% of the acids were mono-unsaturated. 4. 4. The long-chain bases were dominated (95%) by D - erythro -1,3-dihydroxy-2-amino- trans -4, trans -8-octadecadiene. The remaining part was sphingosine. 5. 5. The ceramide obtained by phospholipase hydrolysis was analyzed by gas chromatography and mass spectrometry for molecular species. No evidence for preferential combinations of long-chain base and fatty acid was obtained. 6. 6. Evidence is presented that the long-chain base composition was different for animals captured in April (absence of sphingosine) and animals captured in August (presence of sphingosine).