UC Riverside

Due to rising salinity of freshwater systems and the lack of information about contaminants in saltwater lakes, there is a need for new methods to identify stressors and their effects in saline environments. We propose the use of the saltwater aquatic crustacean, Artemia franciscana, as a model organism for environmental metabolomics analysis of stressors for saltwater ecosystems. Artemia is an ideal indicator species because it is well-studied, have short life-cycles, and are robust. Their hemolymph has a high concentration of small molecule metabolites in an open circulatory system that is susceptible to environmental conditions and amenable to metabolomics analysis. Environmental metabolomics methods use analytical techniques, such as nuclear magnetic resonance (NMR) and mass spectrometry (MS), with chemometric analysis to characterize the interactions of an organism with its environment. When exposed to a stressor, these methods are used to identify biomarkers of exposure and assess the biochemical pathways that are impacted.

The small molecule metabolite profile of Artemia was characterized using 1D and 2D NMR and GC-MS and 43 metabolites were identified. Environmental metabolomics methods were developed using untargeted 1H NMR and GC-MS analysis coupled with high-content imaging to assess Artemia exposed to established and emerging stressors, which included temperature stress, Roundup® herbicide, and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) flame retardant. Targeted metabolomics analysis with LC-MS/MS was introduced to study the effects of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), 118 metabolites were identified with this method. Multivariate and univariate statistical analysis was used to identify biomarkers of exposure for each stressor and pathway analysis identified biochemical pathways that were likely affected. Although each stressor had a unique effect, it was determined that sugars, which are important for energy pathways such as glycolysis, and osmolytes, such as betaine and gadusol, play an important role in Artemia stress response.