PERSPECTIVE pubs.acs.org/est
Introducing High-Throughput Environmental Metabolomics: ES&T’s Top Science Paper 2010 Jerald L. Schnoor*
etabolomics, the systematic study of unique “small molecule” metabolite profiles, has been around for a decade or so in biomedical literature. Its origins trace to metabolic profiling research performed in the early 1970s using GC-MS to examine urine and tissue extracts of humans exposed to disease. Driving the research in recent years have been interests in systems biology and identifying the human metabolome extracted from tissues, cells, or bodily fluids. But metabolomics has not found much application in environmental samples, ... until now. This year’s award for ES&T’s Top Paper in Environmental Science goes to Damian Helbling, Juliane Hollender, Hans-Peter Kohler, Heinz Singer, and Kathrin Fenner at Eawag, the Swiss Federal Institute of Aquatic Science and Technology, for their paper, “High-Throughput Identification of Microbial Transformation Products of Organic Micropollutants,” (Environ. Sci. Technol. DOI 10.1021/es100970m). Miriam Diamond, University of Toronto and ES&T Editorial Advisory Board member, was ecstatic, “Helbling and co-workers have developed a sophisticated but attainable high-throughput screening method borrowed from the field of metabolomics that conducts a broad scan and identifies potential transformation products”. Like much good science, there’s a story within the story of our Top Paper. It began when Kathrin Fenner, the project’s Principal Investigator, spent a sabbatical at the University of Minnesota working with Profs. Lynda Ellis and Larry Wackett on improving a computer-based system to predict biotransformation pathways (UM-PPS, http://umbbd.msi.umn.edu/predict/index.html). Inspired by that experience, Fenner returned to Switzerland and was “eager to carry-out targeted biotransformation experiments to fill data gaps to further train the system”. However, there was a big problem. She did not have any funding for the propitious idea. So she teamed with Kohler, a biochemist accomplished in experimental systems, and analytic chemists Hollender and Singer.
M
r 2011 American Chemical Society
They wrote a successful internal proposal to Eawag for funding explicitly reserved for promising interdepartmental, interdisciplinary research. The final piece of the puzzle fell into place with the hiring of Damian Helbling, postdoc and lead author on the paper (depicted in the accompanying photo), who was keenly interested “in developing an experimental approach to identify the intermediates of biotransformation reactions”. They made a fine team. By using high resolution mass spectrometric techniques, the authors developed an efficient procedure for high-throughput screening of biotransformation products from six pharmaceuticals and six pesticides simultaneously. In so doing, they identified 26 metabolites: 13 had been previously reported in the literature and an equal number of new ones. Perhaps more impressively, they utilized the UM-PPS predictive tool for targeted screening in parallel with nontargeted screening. This was accomplished by using high-resolution full scan MS data from two samples in time and several filters to derive molecular formulas and structures of the transformation products from the exact masses. Associate Editor Jennifer Field was most enthusiastic about the effort to improve modeling tools, “I think Helbling et al. is [an] important [article] because we have long recognized the need for predictive tools in order to move environmental chemistry forward and away from a position where the field only reacts to problems.” Lead author Helbling agreed that the nontarget approach is what makes the paper so exciting: The original idea called for only a targeted screening for biotransformation products based on the predictions of a biodegradation pathway prediction tool. Wariness related to the comprehensive nature of the predictions from this software led to some brainstorming that eventually resulted in the development of the nontarget approach. As detailed in the paper, the complementary use of these two techniques added an additional layer of validation to our results and ultimately made the technique much more exciting. Indeed, the nontargeted screening correctly identified all 26 of the transformation products. Thus, the paper covers new ground in environmental science and introduces a novel technique for metabolomics research in environmental samples like wastewater discharges, hydraulic fracturing fluids in groundwater, and pesticide runoff. That is why it is the Top Science Paper of 2010 in ES&T.
’ AUTHOR INFORMATION Corresponding Author
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[email protected]. Published: March 09, 2011 2520
dx.doi.org/10.1021/es200415t | Environ. Sci. Technol. 2011, 45, 2520–2520
