Dissection of flag leaf metabolic shifts and their relationship with those occurring simultaneously in developing seed by application of non-targeted metabolomics.

Rice flag leaves are major source organs providing more than half of the nutrition needed for rice seed development. The dynamic metabolic changes in rice flag leaves and the detailed metabolic relationship between source and sink organs in rice, however, remain largely unknown. In this study, the metabolic changes of flag leaves in two japonica and two indica rice cultivars were investigated using non-targeted metabolomics approach.

Diagnostic value of plasma tryptophan and symmetric dimethylarginine levels for acute kidney injury among tacrolimus-treated kidney transplant patients by targeted metabolomics analysis.

Few literatures have evaluated the exact role of metabolomics in the identification process of potential biomarkers for acute kidney injury among the patients receiving renal transplantation. On top of this, the success of metabolomics in biomarker translation seems to lie in the robust quantitative method. As such, a single-center retrospective observational study was conducted enrolling 42 patients underwent renal transplantation with/without acute kidney injury, as well as 24 healthy volunteers, in Shanghai Changzheng Hospital.

Occurrence and estrogenic activity of steroid hormones in Chinese streams: A nationwide study based on a combination of chemical and biological tools.

Steroid hormones (SHs) are continuously released into the aquatic environment through various pathways after being excreted by humans and animals, interfere with the normal function of the endocrine system and may affect the physiology and reproduction of exposed aquatic life. To conduct a nationwide investigation of the occurrence and biological effects of SHs in surface river/steam water in China, we quantitated 27 selected SHs in 217 surface water samples by solid-phase extraction (SPE) tandem LC-MS/MS and used a recombinant yeast estrogen assay to screen extracts of the water samples for estrogenic activities. SHs were commonly found in the surface water samples, and their levels were typically in the ng L range.

Targeted metabolomic analysis of 33 amino acids and biogenic amines in human urine by ion-pairing HPLC-MS/MS: Biomarkers for tacrolimus nephrotoxicity after renal transplantation.

Calcineurin inhibitor nephrotoxicity, especially for the widely used tacrolimus, has become a major concern in post-transplant immunosuppression. Multiparametric amino acid metabolomics is useful for biomarker identification of tacrolimus nephrotoxicity, for which specific quantitative methods are highlighted as a premise. This article presents a targeted metabolomic assay to quantify 33 amino acids and biogenic amines in human urine by high-performance liquid chromatography coupled with tandem mass spectrometry.

Photochemical Transformation of Nicotine in Wastewater Effluent.

Nicotine is a highly toxic tobacco alkaloid that is ubiquitous in wastewater effluent. For the first time, we report the identification of the products and the pathways for the photodegradation of nicotine in an effluent matrix under simulated solar irradiation. Nicotine was found to be degraded by triplet-state organic matter (OM*), thus indicating that electron transfer is a preferred reaction mechanism.

Determination of illicit drugs in aqueous environmental samples by online solid-phase extraction coupled to liquid chromatography-tandem mass spectrometry.

In this study, a fully automated analytical method, based on online solid phase extraction coupled to liquid chromatography-triple quadrupole tandem mass spectrometry (online SPE-LC-MS/MS), has been developed and optimized for the quantification of 10 illicit drugs and metabolites in environmentally aqueous samples collected from China. The particular attention was devoted to minimize the matrix effects through a washing step, which washed out the interferences effectively and helped to reduce the matrix effect significantly. The key advantages of the method are high sensitivity, selectivity and reliability of results, smaller sample manipulation, full automation, and fairly high throughput.

Identification of Conserved and Diverse Metabolic Shifts during Rice Grain Development.

Seed development dedicates to reserve synthesis and accumulation and uncovering its genetic and biochemical mechanisms has been a major research focus. Although proteomic and transcriptomic analyses revealed dynamic changes of genes and enzymes involved, the information regarding concomitant metabolic changes is missing. Here we investigated the dynamic metabolic changes along the rice grain development of two japonica and two indica cultivars using non-targeted metabolomics approach, in which we successfully identified 214 metabolites.

Characterization and evaluation of two-dimensional microfluidic chip-HPLC coupled to tandem mass spectrometry for quantitative analysis of 7-aminoflunitrazepam in human urine.

Microfluidic chip-based high-performance-liquid-chromatography coupled to mass spectrometry (chip-HPLC-MS) has been widely used in proteomic research due to its enhanced sensitivity. We employed a chip-HPLC-MS system for determining small molecules such as drug metabolites in biological fluids. This chip-HPLC-MS system integrates a microfluidic switch, a 2-dimensional column design including an enrichment column (160 nL) for sample pre-concentration and an analytical column for chromatographic separation, as well as a nanospray emitter on a single polyimide chip.