| Popis: |
It is crucial to understand the effects caused by experimental parameters, such as temperature; light availability; and food type that can interfere when determining a dose-response relationship in toxicology exposure experiments. Limiting variability is especially important when developing metabolite biomarkers of contaminant exposure since metabolomics is very sensitive to any internal and external factors that affect organism health and metabolic status. Ecotoxicologists are well aware of the importance of experimental design but the type of substrate used in exposure experiments is generally assumed to have no effect and is not assessed. This may not always be correct. Here we investigate the different metabolic changes in the freshwater crustacean, Austrochiltonia subtenuis to the heavy metal copper caused using three common substrate types, gauze; toilet paper; and cellulose. Each substrate type elicited a different metabolic response over the course of the experiment indicating substrate type affected the final results of the exposure test. Metabolites were assessed using Gas Chromatography-Mass Spectrometry. Several groups were shown to change including disaccharides, monosaccharides, fatty acids and their conjugates, and TCA cycle intermediates. The results illustrate that different metabolomic responses can occur from experimental design decisions previously thought not to have a significant effect. This may in turn affect policy decisions based on the results of the experiment. We propose that metabolomics can play an important part in the design of ecotoxicity tests and that all experimental parameters should be assumed to potentially have an effect until proved otherwise. |
