Visualization of phosphatidylcholine,lysophosphatidylcholine and sphingomyelin in mouse tongue body by matrix-assisted laser desorption/ionization imaging mass spectrometry

The mammalian tongue is one of the most important organs during food uptake because it is helpful for mastication and swallowing. In addition, taste receptors are present on the surface of the tongue. Lipids are the second most abundant biomolecules after water in the tongue. Lipids such as phosphatidylcholine (PC), lysophosphatidylcholine (LPC) and sphingomyelin (SM) are considered to play fundamental roles in the mediation of cell signaling. Imaging mass spectrometry (IMS) is powerful tool for determining and visualizing the distribution of lipids across sections of dissected tissue. In this study, we identified and visualized the PC, LPC, and SM species in a mouse tongue body section with matrix-assisted laser desorption/ionization (MALDI)-IMS. The ion image constructed from the peaks revealed that docosahexaenoic acid (DHA)-containing PC, LPC, linoleic acid-containing PC and SM (d18:1/16:0), and oleic acid-containing PC were mainly distributed in muscle, connective tissue, stratified epithelium, and the peripheral nerve, respectively. Furthermore, the distribution of SM (d18:1/16:0) corresponded to the distribution of nerve tissue relating to taste in the stratified epithelium. This study represents the first visualization of PC, LPC and SM localization in the mouse tongue body.     

Abnormal phospholipids distribution in the prefrontal cortex from a patient with schizophrenia revealed by matrix-assisted laser desorption/ionization imaging mass spectrometry

Schizophrenia is one of the major psychiatric disorders, and lipids have focused on the important roles in this disorder. In fact, lipids related to various functions in the brain. Previous studies have indicated that phospholipids, particularly ones containing polyunsaturated fatty acyl residues, are deficient in postmortem brains from patients with schizophrenia. However, due to the difficulties in handling human postmortem brains, particularly the large size and complex structures of the human brain, there is little agreement regarding the qualitative and quantitative abnormalities of phospholipids in brains from patients with schizophrenia, particularly if corresponding brain regions are not used. In this study, to overcome these problems, we employed matrix-assisted laser desorption/ionization imaging mass spectrometry (IMS), enabling direct microregion analysis of phospholipids in the postmortem brain of a patient with schizophrenia via brain sections prepared on glass slides. With integration of traditional histochemical examination, we could analyze regions of interest in the brain at the micrometric level. We found abnormal phospholipid distributions within internal brain structures, namely, the frontal cortex and occipital cortex. IMS revealed abnormal distributions of phosphatidylcholine molecular species particularly in the cortical layer of frontal cortex region. In addition, the combined use of liquid chromatography/electrospray ionization tandem mass spectrometry strengthened the capability for identification of numerous lipid molecular species. Our results are expected to further elucidate various metabolic processes in the neural system.     

Monitoring the aggregation processes of amyloid-β using a spin-labeled, fluorescent nitroxyl radical

Amyloid nitroxyl radical (nitroxide) ligands were used to detect amyloid-β fibrils, the main constituents of senile plaques in Alzheimer's disease, using anisotropic ESR spectra, and were found to affect the aggregation process due to the radical functionality. These compounds have great potential as novel and multifunctional probes, combining spin labels, spin probes, and fluorescence probes.     

Family of symplectic implicit Runge-Kutta formulae

A family of formulae for the sympletic IRK method is investigated. Specifically, focus is given to general solutions for formula parameters of IRK under the symplectic and the order conditions. Examples of such formulae are constructed for up to three stages.     

Isolation and structures of euonymine and neoeuonymine,alkaloids from Euonymus Sieboldiana blume

Two new alkaloids, euonymine 5 and neoeuonymine 14 were isolated from Euonymus Sieboldiana Blume. The structures of euonymine and neoeuonymine were established to be 5 and 14, respectively, by chemical and spectral means: the structural features of euonymine 5 are that it is a polyhydroxyl sesquiterpene of eudesman type (euonyminol) which is esterified with evoninic acid 3 and six moles of acetic acid. Neoeuonymine 14 was converted to euonymine 5. Direct conversion of evonine 1 to euonymine 5 was also achieved.     

Kinetic study of transmembrane electron transport by the hinkle process

Trans-membrane redox reactions mediated by t-amylferrocene (one-electron carrier) were studied kinetically in a liposome system separating two redox pairs (ferricyanide/ferrocyanide and dehydroascorbate/ascorbate). In order to eliminate the membrane potential generated, which suppressed the rate of the reaction, the rate was measured in the presence of carbonylcyanide m-chlorophenylhydrazone. The reaction rate was independent of concentrations of ascorbate and dehydroascorbate. Ferricyanide also had virtually no effect on the rate, but addition of ferrocyanide decreased it. The results were analysed on the basis of rate equations derived from the possible reaction mechanism, and it was concluded that the rate-determining step of the trans-membrane redox reaction was the process of diffusion of the mediator in the membrane.     

Compression curve of BaBiO3

The compression curve of BaBiO₃ was measured by X-ray diffraction method using a diamond anvil cell apparatus up to about 8 GPa. The diffraction pattern did not change in this pressure range, but the bulk modulus suddenly decreased near 4 GPa. The initial value of the bulk modulus, 157 GPa was estimated from the data up to 4 GPa.     

Cyano-bridged Mn(III)3M(III) (M(III) = Fe, Cr) complexes: synthesis, structure, and magnetic properties

Two cyano-bridged tetranuclear complexes composed of Mn(III) salen (salen = N,N'-ethylene bis(salicylideneiminate)) and hexacyanometalate(III) (M = Fe, Cr) in a stoichiometry of 3:1 have been selectively synthesized using {NH2(n-C12H25)2}3[M(III)(CN)6] (M(III) = Fe, Cr) starting materials: [{Mn(salen)(EtOH)}3{M(CN)6}] (M = Fe, 1; Cr, 2). Compounds 1 and 2 are isostructural with a T-shaped structure, in which [M(CN)6]3- assumes a meridional-tridentate building block to bind three [Mn(salen)(EtOH)]+ units. The strong frequency dependence and observation of hysteresis on the field dependence of the magnetization indicate that 1 is a single-molecule magnet.