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Lipid, fatty acid, and sterol composition of eight species of Kareniaceae (dinophyta): chemotaxonomy and putative lipid phycotoxins

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Mooney, B and Nichols, PD and de Salas, MF and Hallegraeff, GM (2007) Lipid, fatty acid, and sterol composition of eight species of Kareniaceae (dinophyta): chemotaxonomy and putative lipid phycotoxins. Journal of Phycology, 43 (1). pp. 101-111. ISSN 0022-3646

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Abstract

The lipid class, fatty acid, and sterol composition
of eight species of ichthyotoxic marine gymnodinioid
dinoflagellate (Karenia, Karlodinium,
and Takayama) species was examined. The major
lipid class in all species was phospholipid
(78%–95%), with low levels of triacylglycerol
(TAG; 0%–16%) and free fatty acid (FFA; 1%–
11%). The common dinoflagellate polyunsaturated
fatty acids (PUFA), octadecapentaenoic acid (OPA
18:5x3), and docosahexaenoic acid (DHA 22:6x3),
were present in all species in varying amounts
(14%–35% and 8%–23%, respectively). The verylong-
chain PUFA (VLC-PUFA) 28:7x6 and 28:8x3
were present at low levels (<1%), and the ratio of
these fatty acids may be a useful chemotaxonomic
marker at the species level. The typical dinoflagellate
sterol dinosterol was absent from all species
tested. A predominance of the 4-methyl and 4-desmethyl
D8(14) sterols in all dinoflagellate species included
23-methyl-27-norergosta-8(14),22-dien-3b-ol
(Karenia papilionacea A. J. Haywood et Steid, 59%–
66%); 27-nor-(24R)-4a-methyl-5a-ergosta-8(14),22-
dien-3b-ol, brevesterol, (Takayama tasmanica de
Salas, Bolch et Hallegraeff 84%, Takayama helix de
Salas, Bolch, Botes et Hallegraeff 71%, Karenia
brevis (C. C. Davis) G. Hansen et Moestrup 45%,
Karlodinium KDSB01 40%, Karenia mikimotoi
(Miyake et Kominami ex Oda) G. Hansen et
Moestrup 38%); and (24R)-4a-methyl-5a-ergosta-
8(14),22-dien-3b-ol, gymnodinosterol, (K. mikimotoi
48%, Karenia umbella de Salas, Bolch et Hallegraeff
59%, Karlodinium veneficum (D. L. Ballant.) J. Larsen
71%–83%). In Takayama species, five steroid
ketones were identified, including for the first time
the 3-keto form of brevesterol and gymnodinosterol.
These results indicate a biochemical link between
sterol and steroid ketone biosynthesis, suggesting
that selected dinoflagellates can make a significant
contribution to ketones in marine sediments. The
presence of steroid ketones, specific sterols, and
fatty acids, and the ratio of VLC-PUFA may prove to
be a useful chemotaxonomic tool for distinguishing
between morphologically similar species. The relative
levels of the PUFA, OPA, and DHA, coupled
with the potential inhibitory action of D8(14) sterols,
may provide an insight into the ichthyotoxicity of
these bloom-forming dinoflagellates.

Item Type: Article
Journal or Publication Title: Journal of Phycology
Publisher: Blackwell Publishing
Page Range: pp. 101-111
ISSN: 0022-3646
Identification Number - DOI: 10.1111/j.1529-8817.2006.00312.x
Date Deposited: 07 Apr 2008 14:41
Last Modified: 18 Nov 2014 03:36
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