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The term "omics" refers to the study of the entirety of molecular mechanisms that happen inside an organism. With the advent of omics technologies like transcriptomics, proteomics, metabolomics, and lipidomics, our understanding of molecular pathways of toxic environmental pollutants has deepened.

But most environmental toxicology studies are still dependent on single-omics analyses, leading to gaps in our understanding of integrated toxicity pathways of pollutants. Researchers from all over the world have been trying to build reliable biomolecule analyses by designing multi-omics studies from a single biological sample.

Although such advances have been reported from various model systems like mammalian cells, Caenorhabditis elegans, etc., toxicology studies on zebrafish are still based on single-omics analyses using individually prepared biological samples. However, selection of appropriate extraction solvents and pooling size for accurate omics analyses is still a challenge in zebrafish toxicology studies.

To address this gap, a research team led by Professor Ki-Tae Kim has now proposed a novel approach for simultaneous extraction of metabolites and lipids for multi-omics analyses from a single sample using zebrafish embryos. Their study is in the Journal of Hazardous Materials.

For this, the researchers used a methyl tert-butyl ether (MTBE)-based extraction strategy using a single biological sample from zebrafish embryos for simultaneous metabolomics and lipidomics analyses.

Prof. Kim states, "To increase the applicability of our findings to environmental toxicology, we elucidated the biomolecular mechanisms underlying PFOS-induced neurobehavioral changes and evaluated the analytical performance of the MTBE-based strategy by comparing it with previous findings of PFOS-induced metabolomic dysregulation."

In their study, Prof. Kim and his team determined the optimal embryo pooling size for the application of MTBE-based extraction. The inter-sample variation was the least when 30 or more larvae were used. They thus suggest using 30 larvae as the optimum pooling size for the simultaneous analysis of metabolomics and lipidomics.

Their novel extraction strategy also revealed many lipids and metabolites compared to the conventionally used extraction solvents. Application of the MTBE-based strategy helped record the changes in metabolites and lipids linked to energy metabolism in PFOS-exposed zebrafish larvae.

"The disruption of metabolites and lipids revealed the biomolecular mechanism underlying the alteration of larval behavior by affecting biological processes like energy metabolism including disrupted amino acids and fatty acid metabolism," says Prof. Kim. In addition, the comprehensive profiling of biomolecular dysregulations in this study helped identify sphingolipids as a reliable biomarker of PFOS-induced neurotoxicity.

This approach of using a single sample for multi-omics study can be expanded to a variety of biomolecules, leading to the management of toxicity at the biomolecular level. Furthermore, the proposed approach can help in developing a safer and healthier environment in future by facilitating research on the measure of exposure to environmental pollutants.

As is well known, PFOS is one of the most prevalent environmental pollutants commonly found in aquatic ecosystems. Biomonitoring studies have reported high concentrations of it in water, human blood and even human cerebrospinal fluid. Reliable analysis of biomolecules in a single sample is indispensable for multi- and integrative omics, with wide applications in understanding molecular dysregulations by such toxic chemicals.

Highlighting the potential of this strategy for expediting such analysis, Prof. Kim says, "The developed method will trigger mechanism-based classification studies of per- and polyfluoroalkyl substances and contribute to the advancement of multi-omics analysis technologies in environmental toxicology."