Identification of novel n-4 series polyunsaturated fatty acids in a deep-sea clam, Calyptogena phaseoliformis

J Chromatogr A. 2007 Sep 7;1163(1-2):247-59. doi: 10.1016/j.chroma.2007.06.016. Epub 2007 Jun 16.


Novel fatty acids originated from the cold-seep clam Calyptogena phaseoliformis, collected from hydrothermal vents in the Japan Trench at a depth of 6354-6367 m, were determined by using gas chromatography-mass spectrometry analysis of the 4,4-dimethyloxazoline derivatives. The major fatty acids present in the C. phaseoliformis lipids belong to the n-4 family non-methylene interrupted polyunsaturated fatty acids (NMI-PUFA): 20:3n-4,7,15, 20:4n-1,4,7,15, and 21:3n-4,7,16, with significant levels of 20:2n-7,15 and 21:2n-7,16 as non-methylene interrupted n-7 dienes. Compared with the lipids of shallow-water clam Mactra chinensis, which contains photosynthetic n-3 PUFA, such as docosahexaenoic acid and icosapentaenoic acid, C. phaseoliformis might have an intrinsic mechanism in vivo so as to maintain the fluidity of the high-melting fatty acids in the membrane lipids by exogenous n-4 family PUFA adaptation as substitutes. Such special kinds of fatty acids are assimilated by the symbiotic chemosynthetic bacteria, which use geothermal energy and minerals from the cold-seep vents. Its unique fatty acid composition corresponding to the novel n-4 family NMI-PUFA markedly differs from those of the reported lipid compositions of other marine animals, which depend on the marine grazing food chain originating from phytoplankton. Thus, the present findings confirm a perfect and closed novel food chain in the cold-seep bivalve and in its symbionts, which is independent from the photosynthetic food chain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bivalvia / chemistry*
  • Chromatography, Thin Layer
  • Fatty Acids, Unsaturated / analysis*
  • Fatty Acids, Unsaturated / chemistry
  • Gas Chromatography-Mass Spectrometry
  • Magnetic Resonance Spectroscopy
  • Molecular Structure
  • Oxazoles / analysis
  • Oxazoles / chemistry


  • Fatty Acids, Unsaturated
  • Oxazoles
  • 4,4-dimethyloxazoline