Comparative lipidomic analysis of phospholipids of hydrocorals and corals from tropical and cold-water regions

Abstract

To expand our knowledge of lipid and fatty acid (FA) biosynthesis in marine cnidarians, polar lipidomes of hydrocorals were studied for the first time and then compared with those of soft corals from tropical and boreal regions. The structure and content of FAs and molecular species of ethanolamine, choline, serine, and inositol glycerophospholipids (PE, PC, PS, and PI, respectively), and ceramide aminoethylphosphonate (CAEP) in tropical hydrocorals ( Millepora platyphylla , M . dichotoma ) and the cold-water hydrocoral Allopora steinegeri were determined by chromatography and mass spectrometry. All soft corals and cold-water hydrocorals are characterized by a considerable amount of C 20 polyunsaturated FAs (PUFAs) elongated into C 22 PUFAs. In the Millepora species, the high level of 22:5n-6 and 22:6n-3 against the background of the extremely low level of C 20 PUFAs may be explained by a high activity of rare Δ4 desaturase. In contrast to hydrocorals, soft corals are able to elongate and further desaturate C 22 PUFAs into C 24 PUFAs. Allopora and soft corals use C 20 PUFAs mainly for the synthesis of PE and PC. The molecular species of PS of soft corals concentrate C 24 PUFAs, while in Allopora and Millepora the PS molecules are mainly based on 22:4n-6 and 22:5n-6 acyl groups, respectively. Short acyl groups (C 14 ) dominate the CAEP molecules of Allopora . In all the animals compared, most molecular species of PE and PC are ether lipids, but diacyl molecular species dominate PI. Hydrocorals and tropical soft corals contain diacyl and ether PS molecules, respectively, whereas cold-water soft corals contain a mixture of these PS forms. The high similarity of the alkyl/acyl compositions indicates a possible biosynthetic relationship between PS and PI in hydrocorals. The data obtained in our study will provide a resource to further investigate the lipid metabolism in marine invertebrates.

Lipidomic study of the influence of dietary fatty acids on structural lipids of cold-water nudibranch molluscs

“…The chemical structure of the PL molecular species was identified as described earlier (Supplementary Figs. S5–S9) 21,22,49 . Quantification of individual molecular species within each PL class was carried out by calculating the peak areas for the individual extracted ion chromatograms.…”

“…The analysis approach was recently described 22 . Briefly, significance of differences in mean contents of FAs, lipid classes, and lipid molecular species between nudibranch species was tested by one-way analysis of variance (ANOVA).…”

“…Nevertheless, an intensive “flux” of unusual dietary lipids and FAs seems to strongly modify the profile of polar lipid molecular species (polar lipidome) of nudibranchs with a specialized type of feeding (stenophagy) 15,21 . The first analysis of the polar lipidome of the nudibranch T. tetraquetra showed that unusual TPA, concentrated in serine glycerophospholipids (PS) of its prey 22,23 , are redistributed in the consumer to other polar lipid classes and accumulated in all tissues 21 . Does it mean that nudibranchs are what they eat?…”

Lipidomic profiling reveals biosynthetic relationships between phospholipids and diacylglycerol ethers in the deep-sea soft coral Paragorgia arborea

“…Marine invertebrates are a paraphyletic systematic group comprising more than 90% of all marine animal species, but data on their lipidomes are very limited to date 9 . These lipidomes have been partly described from some species of shrimp 10 – 12 , lobsters 13 , crabs 14 , 15 , jellyfish 16 , 17 , starfish 18 , sea urchins 18 , holothurians 18 , bivalves 19 – 25 , gastropods 26 , nudibranch molluscs 27 , 28 , sponges 29 , and hydrocorals 30 , 31 . Among coral polyps (the class Anthozoa), lipidome or its polar part has been analyzed in some species belonging to four orders: Scleractinia (reef-building corals) 32 – 34 , Alcyonacea (soft corals) 35 – 37 , Zoantharia 38 , and Actiniaria (sea anemones) 39 – 41 .…”

“…The influence of environmental parameters and pollutions on cell physiology was assessed by analyzing the lipidome of reef-building corals 32 – 34 , 43 . Different patterns of distribution of polyunsaturated FA (PUFA) among structural lipid classes were demonstrated for different taxa of soft corals and hydrocorals from tropical and cold-water regions 30 . A lipidome analysis allowed simultaneous monitoring of lipid dynamics of both symbiotic dinoflagellates and host tissues during coral bleaching 44 , 45 .…”