Origin of Marine Fatty Acids. I. Analyses of the Fatty Acids Produced by the DiatomSkeletonema costatum

1964 ◽  
Vol 21 (4) ◽  
pp. 747-756 ◽  
Author(s):  
R. G. Ackman ◽  
P. M. Jangaard ◽  
R. J. Hoyle ◽  
H. Brockerhoff
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Laboratory Experiments ◽  
Unsaturated Fatty Acids ◽  
Skeletonema Costatum ◽  
Marine Diatom ◽  
Highly Unsaturated Fatty Acids ◽  
Diatom Skeletonema Costatum

Analysis of the fatty acid composition of a marine diatom, Skeletonema costatum, shows that the longer-chain highly unsaturated fatty acids characteristic of fish lipids can be produced by some phytoplankton as well as through intermediary zooplankton. Comparison of cultures of various degrees of maturity indicates that the fatty acid composition of mature cultures in laboratory experiments is not necessarily typical of pelagic diatoms. The origin of atypical C16-polyunsaturated fatty acids is discussed.

A membrane-bound glycerol-3-phosphate acyltransferase from Thalassiosira pseudonana regulates acyl composition of glycerolipidsThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽  
2009 ◽  
Vol 87 (6) ◽  
pp. 544-551 ◽  
Author(s):  
Jingyu Xu ◽  
Zhifu Zheng ◽  
Jitao Zou
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Unsaturated Fatty Acids ◽  
Thalassiosira Pseudonana ◽  
Marine Diatom ◽  
Dihydroxyacetone Phosphate ◽  
Lipid Species ◽  
Membrane Bound

To what extent fatty acyltransferases control fatty acid composition in glycerolipids is largely unknown. To gain some insight into this process, we characterized a membrane-bound glycerol-3-phosphate acyltransferase (GPAT), designated TpGPAT, from the marine diatom Thalassiosira pseudonana Hasle & Heim. The glycerolipids from T. pseudonana consist predominantly of 16:0, 16:1ω7, and 20:5ω3 fatty acids. Heterologous expression of TpGPAT in a yeast GPAT-deficient mutant (gat1) demonstrated that TpGPAT could effectively use glycerol-3-phosphate, but not dihydroxyacetone phosphate, as fatty acyl acceptor. This enzyme highly preferred 16:0 in an in vitro enzyme assay, and discriminated against the monounsaturated 16-carbon fatty acid. Accordingly, expression of TpGPAT in gat1 resulted in approximately 18% and 12% increases of 16:0 in triacylglycerols and phospholipids, respectively. The unsaturated fatty acids, 16:1 and 18:1, on the other hand, were reduced by 15% and 21% in these two lipid species. Collectively, the results demonstrate that TpGPAT possesses a high substrate preference for 16:0-CoA and it exerts a large effect on the fatty-acid composition of glycerolipids.

Description of Oncholaimus moanae sp. nov. (Nematoda: Oncholaimidae), with notes on feeding ecology based on isotopic and fatty acid composition

2008 ◽  
Vol 89 (2) ◽  
pp. 337-344 ◽  
Author(s):  
Daniel Leduc
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Unsaturated Fatty Acids ◽  
Feeding Habits ◽  
Nematode Species ◽  
Trophic Levels ◽  
Sediment Surface ◽  
Highly Unsaturated Fatty Acids

A new free-living marine nematode species, Oncholaimus moanae sp. nov., is described from intertidal fine sand in southern New Zealand. Oncholaimus moanae sp. nov. can be distinguished from other species of the genus by the presence of a pre-cloacal papilla bearing four pairs of short, stout spines, a post-cloacal papilla, long (>70 μm) spicules, and a demanian system with two openings situated laterally at level of uvette. The δ13C signature of O. moanae sp. nov. suggests that benthic microalgae are the main carbon source for this species, but an elevated δ15N signature suggests predatory feeding habits. The fatty acid composition of O. moanae sp. nov. is rich in highly unsaturated fatty acids, which are likely to originate from heterotrophic protists (e.g. ciliates). The data obtained in this study suggest, for the first time, that marine nematodes can be a high quality food source (i.e. rich in highly unsaturated fatty acids) to predators. Large nematodes living near or at the sediment surface, in particular, may represent an important trophic link between heterotrophic protists and higher trophic levels in marine sediments.

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