Putting the Oxylipidome to Work: A Novel Lipidomics Pipeline Reveals Candidate Biomarkers for Photooxidative Stress in Phytoplankton

The lipids of marine plankton encompass a diversity of biochemical functions and chemotaxonomic specificities that make them ideal molecular biomarkers in living biomass. While core, nonpolar lipids such as free fatty acids (FFA) have formed the basis for many biomarker studies in fresh biomass, methods that enable the simultaneous profiling of core lipids and intact polar lipids (IPL) have opened new avenues for characterization of environmental stressors. We demonstrate the application of a novel, rules-based lipidomics data analysis pipeline to putatively identify a broad range of intact polar lipids, intact oxidized lipids (ox-lipids) and oxylipins in accurate-mass HPLC-ESI-MS data. Using mass spectra from a lipid peroxidation experiment conducted under the natural, ultraviolet-enriched light field in West Antarctica, we use the pipeline to identify ox-lipid and oxylipin biomarkers that might serve as indicators of photooxidative stress in phytoplankton. The lipidomics pipeline derives much of its functionality from two boutique lipid-oxylipin databases, which together contain entries for more than 60,000 candidate lipid biomarkers. These databases and all scripts required by the pipeline will be publicly available online to other users.