Nontargeted lipidomics in nesting females of three sea turtle species in Florida by ultra-high-pressure liquid chromatography–high-resolution tandem mass spectrometry (UHPLC–HRMS/MS) reveals distinct species-specific lipid signatures

In recent years, the utility of lipidomics has been recognized in environmental toxicology and biomonitoring efforts due to the ubiquitous nature and importance of lipids in many cellular processes including signal transduction, energy storage, and cellular compartmentalization. Additionally, technological advances in high-resolution mass spectrometry have enabled the rapid expansion of the field, creating a surge in interest in comparative studies of lipid metabolism from a Systems Biology standpoint. Here, we adapted a nontargeted lipidomic approach for the study of plasma samples from nesting female leatherback ( Dermochelys coriacea ), loggerhead ( Caretta caretta ), and green ( Chelonia mydas ) sea turtles in Florida using ultra-high-performance liquid chromatography/high-resolution tandem mass spectrometry. We identified 877 lipids in common between the three species, of which the concentrations for 467 lipids were statistically different between two or more group comparisons. Principal component analysis revealed unique lipidomic signatures associated with each species of turtle, including various glycerophosphatidylcholines, glycerophosphatidylethanolamines, triacylglycerols, and oxidized triacylglycerols that were higher in leatherback sea turtles, diacylglycerols and select glycerophosphatidylinositols which were higher in loggerhead sea turtles, and specific plasmanyl-phosphatidylcholines that were higher in green sea turtles. Our results indicate that lipidomic profiling can be a useful tool for studying lipid metabolism and physiology of different species of sea turtles, while establishing baseline data that may be used as reference in future studies for observation of differences in life stages, for following spatial and temporal trends in nesting turtles, and for investigating population dynamics in response to various stressors.