Transcriptome and metabolome analysis in tomato (Solanum lycopersicum) fruits cultivated under drought conditions showed that drought stress promoted fatty acid synthesis and increased the content of fatty acids in fruits. The accumulation of some phospholipids composed of palmitic acid and oleic acid also was significantly increased, especially in seeds. Moreover, inositol, which is a component of cell membranes and cell walls, was increased through the activity of the myoinositol monophosphatase 1-mediated pathway. In mature fruits, the levels of metabolic regulators such as β-alanine and 4-aminobutyric acid were elevated. These results showed that these compounds are drought-responsive and enhance drought tolerance and subsequently they could enhance the nutritional value and health benefits of tomato fruit.

We prepared functionalized magnetic nanoparticles (d = 3.5 nm) to serve as a laser desorption/ionization material for mass spectrometry. The obtained nanoparticles consisteds of a macaulayite core conjugated with hydroxyl and amino groups, and showed superparamagnetism at room temperature. The nanoparticles by themselves could ionize the sample peptide, drug and proteins (approx. 5000 Da) without causing background peaks. In the detection of biomolecules by mass spectrometry, the analytes are generally extracted from biological samples, and undergo futher purification and desaltation. However, these processing steps cause analyte loss. In the present study, we tried to detecting biomolecules in cultured cells without extraction or desaltation, but by using nanoparticles and a permanent magnet. The nanoparticles were introduced into living cells cultured on indium tin oxide-coated glass slides and accumulated on the surface of the cultured cells using an external magnetic field. The direct mass spectrometry of the cultured cells showed that we successfuly profiled the phospholipids of the cells. Our new nanoparticle-assisted laser desorption/ionization mass spectrometry technique is a quick and convenient way to profile biomolecules in cultured cells.

We analyzed the localization of ubiquinol, the reduced form of coenzyme Q10 (Re-CoQ10), in mouse brain sections using matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance imaging mass spectrometry (IMS) to evaluate the effect of dietary Re-CoQ10 in mouse brain. Mice were orally administered Re-CoQ10 for 14 days and brain Re-CoQ10 content was subsequently quantified using liquid chromatography-mass spectrometry. IMS was employed to visualize Re-CoQ10 at a resolution of 150 μm in the mouse brain. Increased Re-CoQ10 was observed in the corpus callosum, hippocampus, midbrain, cerebellum, brain stem, substantia nigra and striatum. These regions are related to movement, memory and vital life functions. Thus, we demonstrated the effect of Re-CoQ10 administration on the specific localization of Re-CoQ10 in the brain.