Lipid class
distribution of highly unsaturated long chain fatty acids in marine
dinoflagellates
J.D. Leblond, P.J. Chapman-2000
Journal of Phycology, 36 (6) : 1103-1108
(from Current Contents)
Abstract :
The very long chain highly unsaturated C-28 fatty
acids, octacosaheptaenoic [28:7(11-6)] and octacosaoctaenoic acid
[28:8(n-3)], were found to be associated with phospholipids, obtained by
fractionation of total lipid extracts into distinct lipid classes, in 4 and
6, respectively, of 16 examined dinoflagellates, An inter-fraction
comparison of fatty acids associated with phospholipids and glycolipids has
also shown that the phospholipid fractions contained the majority (over 75%
in 12 of 16 strains) of docosahexaenoic acid [22:6(n-3)] and traces of
tetracosanoic acid (24:0), By contrast, the highly unsaturated C-18 fatty
acids octa-decatetraenoic [18:4(n-3)] and octadecapentaenoic acid
[18:5(n-3)] were primarily recovered from a chloroplast-associated
glycolipid fraction comprised of monogalactosyldiacylglycerol,
digalactosyldiacylglycerol, and sulfoquinovosyldiacylglycerol. In 12 of 16
strains, an interfraction comparison showed that over 90% of 18:5(n-3) was
found to be associated with glycolipids, These findings indicate that the
C-28 fatty acids are located and probably synthesized in the cytoplasm or in
an organelle other than the chloroplast, possibly with 22:6(n-3) and 24:0 as
precursors, whereas the C-18 fatty acids 18:4(n-3) and 18:5(n-3) are
glycolipid constituents apparently synthesized within the chloroplast, The
function(s) of these C-28 fatty acids as components of phospholipids in
cellular membranes is currently unknown.
(Middle Tennessee State Univ, Dept Biol, POB 60,
Murfreesboro, TN 37132, USA, e-mail: jleblond@mtsu.edu)