Tracing of lipid markers of soft corals in a polar lipidome of the nudibranch mollusk Tritonia tetraquetra from the Sea of Okhotsk

• Published in: Polar biology 2019-02, Vol.42 (2), p.245-256
• Main Authors: Imbs, Andrey B., Chernyshev, Alexei V.
• Format: Article
• Language: English
• Subjects: Analysis; Animal species; Biomedical and Life Sciences; Choline; Corals; Ecology; Ecosystems; Esterification; Ethanolamine; Fatty acids; Gersemia fruticosa; High performance liquid chromatography; HPLC; Interactions; Invertebrates; Life Sciences; Lipids; Liquid chromatography; Marine ecosystems; Marine environment; Marine invertebrates; Markers; Mass spectrometry; Mass spectroscopy; Microbiology; Molecular structure; Mollusks; Oceanography; Offshore structures; Original Paper; Phospholipids; Plant Sciences; Predators; Prey; Serine; Shellfish; Tritonia tetraquetra; Trophic levels; Uptake; Zoology
• ISSN: 0722-4060; 1432-2056
• DOI: 10.1007/s00300-018-2418-y

To trace predator‒prey interactions in the marine environment, fatty acids (FAs) were widely applied as qualitative markers. Recently, two tetracosapolyenoic acids (TPA), which are specific markers of soft corals, have been found in the nudibranch mollusk Tritonia tetraquetra collected in the deep waters of the Sea of Okhotsk. This mollusk does not synthesize TPA but preys mostly on the soft coral Gersemia fruticosa . Both invertebrates are common species in Arctic and boreal regions and may be a simple model for the investigation of FA marker transfer from one trophic level to another. A lipidomic approach was applied to study the transfer of the FA markers in this predator–prey system. The structure and content of the molecular species of polar lipids (polar lipidome) of both animal species were analyzed by high-performance liquid chromatography with high-resolution tandem mass spectrometry. The distribution of several principal FA markers in lipid molecular species was determined. C 20 monoenoic FAs of the coral were not integrated in the most of nudibranch lipids. Arachidonic and eicosapentaenoic acids mainly esterified ethanolamine and choline glycerophospholipids (PE and PC) in both invertebrates. In the coral polar lipidome, TPA concentrated in serine glycerophospholipids (PS). The nudibranch decomposed coral lipids and reallocated TPA to PS, PE, and PC. We suppose that this reallocation is responsible for the accumulation of TPA in the nudibranch. The nudibranch differed from the coral in biosynthetic relationships of phospholipid classes. The lipidomic approach explains the rearrangement of dietary FAs in the predator lipids. This rearrangement can be important for the trophic uptake and transfer of lipids in polar marine ecosystems.