Predictive liver lipid biomarker signature of Acetyl-coenzyme A carboxylase inhibitor related developmental toxicity in non-pregnant female Han Wistar rats - Lipidomics biomarker discovery and validation.

INTRODUCTION: Acetyl-coenzyme A carboxylase (ACCase) inhibition is an attractive herbicide target. However, issues with fetal developmental toxicity identified at the late stages of the development process can halt progression of previously promising candidates. OBJECTIVES: To select and verify predictive lipid biomarkers of ACCase inhibition activity in vivo using liver samples obtained from early stage 7 day repeat dose studies in non-pregnant female Han Wistar rats that could be translated to developmental toxicity endpoints discovered during late-stage studies to provide an early screening tool. METHODS: Liver samples from eight rat repeat dose studies, exposed to six ACCase inhibitors from three different chemistries and one alternative mode of action (MoA) that also perturbs lipid biochemistry, were analysed using liquid chromatography - high resolution accurate mass - mass spectrometry. Multivariate and univariate data analysis methods were used for biomarker discovery and validation. RESULTS: A biomarker signature consisting of sixteen lipids biomarkers were selected. Verification of the signature as indicative of ACCase inhibition was established by demonstrating consistent perturbations in the biomarkers using two different ACCase inhibitor chemistries and the lack thereof with an alternate MoA. The fold change profile pattern was predictive of which test substance doses would or would not cause developmental toxicity. CONCLUSION: A strategy for selecting and verifying a robust signature of lipid biomarkers for predicting a toxicological end point has been described and demonstrated. Differences in lipidomic profiles correlated with developmental toxicity suggesting that indicators of a molecular initiation event resulting in pup developmental toxicity can be predicted from short term, toxicity studies conducted in non-pregnant adult female Han Wistar rats.

High throughput quantitative volatile profiling of melons with silicone rod extraction - thermal desorption - GC-MS for plant breeding line selection.

Volatile compounds determine the aroma of fruits, giving their unique flavor characteristics. The aim of many plant breeding projects is to improve the consumers' flavor experience when eating fresh produce. Large scale breeding trials produce thousands of samples which need volatile profiling amongst other phenotypes. Despite this interest, current methods have limitations: sampling unsuitable for field conditions, high cost and the inherent issue of highly variable data, which can hinder interpretation. We introduced a simple and robust sampling methodology based on silicone rod extraction, thermal desorption gas chromatography - mass spectrometry (GC-MS) to address these issues. We used differentiated calibration standards to generate quantitative data for metabolites of varying abundance. The method was used to profile 327 melons with high sensitivity (0.05-10 ng/mL, compound dependent), good reproducibility (7%) and differentiate melon varieties based on their volatile profile. The data were then used for line selection for a desired flavor profile.