Three-Dimensional Image of Cleavage Bodies in Nuclei Is Configured Using Gas Cluster Ion Beam with Time-of-Flight Secondary Ion Mass Spectrometry.

Structural variations of DNA in nuclei are deeply related with development, aging, and diseases through transcriptional regulation. In order to bare cross sections of samples maintaining sub-micron structures, an Ar2500(+)-gas cluster ion beam (GCIB) sputter was recently engineered. By introducing GCIB sputter to time-of-flight secondary ion mass spectrometry (TOF-SIMS), we analyzed the 3D configuration and chemical composition of subnuclear structures of pyramidal cells in the CA2 region in mouse brain hippocampus.

Palmitic acid, verified by lipid profiling using secondary ion mass spectrometry, demonstrates anti-multiple myeloma activity.

Recent studies indicate that lipid metabolic changes affect the survival of multiple myeloma (MM) cells. Time-of-flight secondary ion mass spectrometry (TOF-SIMS), an imaging mass spectrometry technique, is used to visualize the subcellular distribution of biomolecules including lipids. We therefore applied this method to human clinical specimens to analyze the membrane fatty acid composition and determine candidate molecules for MM therapies.

Single-cell time-of-flight secondary ion mass spectrometry reveals that human breast cancer stem cells have significantly lower content of palmitoleic acid compared to their counterpart non-stem cancer cells.

Lipids comprise the primary component of cell membranes. Imaging mass spectrometry is increasingly being used to visualize membranous lipids in clinical specimens, and it has revealed that abnormal lipid metabolism is related to the development of diseases. To characterize cell populations which are rare and sparsely localized in tissues, we conducted time-of-flight secondary ion mass spectrometry (TOF-SIMS) analyses of individual cells sorted by fluorescence activated cell sorting (FACS) and applied the method to analyze breast cancer stem cells (CSCs).

The stratum corneum comprises three layers with distinct metal-ion barrier properties.

The stratum corneum (SC), the outermost barrier of mammalian bodies, consists of layers of cornified keratinocytes with intercellular spaces sealed with lipids. The insolubility of the SC has hampered in-depth analysis, and the SC has been considered a homogeneous barrier. Here, we applied time-of-flight secondary ion mass spectrometry to demonstrate that the SC consists of three layers with distinct properties.

TOF-SIMS imaging of halide/thiocyanate anions and hydrogen sulfide in mouse kidney sections using silver-deposited plates.

In vivo imaging of reactive small molecule metabolites with high spatial resolution and specificity could give clues to understanding pathophysiology of various diseases. We herein applied time of flight-secondary ion mass spectrometry (TOF-SIMS) to newly developed silver-deposited plates that were stamped on mouse tissues, and succeeded in visualization of halide (Cl(-), Br(-), and I(-)) and pseudohalide thiocyanate (SCN(-)) anions, a class of substrates for neutrophils/eosinophil peroxidases to produce hypohalous acids (HOX/OX(-) mixture; X: (pseudo)halides), as well as hydrogen sulfide (H(2)S). Forty-micrometer frozen mouse kidney sections on cover glasses were attached to 37 °C preheated silver-deposited plates and incubated at -10 °C for 1 h.

Detection of characteristic distributions of phospholipid head groups and fatty acids on neurite surface by time-of-flight secondary ion mass spectrometry.

Neurons have a large surface because of their long and thin neurites. This surface is composed of a lipid bilayer. Lipids have not been actively investigated so far because of some technical difficulties, although evidence from cell biology is emerging that lipids contain valuable information about their roles in the central nervous system.

Studies of DNA recognition mechanism of transcription factor IRF-4.

Transcription factor IFN regulatory factor-4 (IRF-4) prefers a DNA sequence including CCGAAA, though the consensus DNA-binding sequence of the IRF family proteins is NNGAAA, and the crystal structure of PU.1/IRF-4/DNA (GTGAAA) ternary complex indicates the NN region of DNA does not interact with IRF-4 directly. This suggests that there is an indirect DNA recognition mechanism in IRF-4.

Solution NMR study of DNA recognition mechanism of IRF4 protein.

Transcription factor IRF-4 prefers the DNA sequence including CCGAAA. The consensus sequence of the IRF family proteins is NNGAAA, and all crystal structures indicate the NN region does not interact with IRF proteins directly. Here the sequence preference of IRF-4 was investigated by NMR and fluorescence antisotropy as an example of the indirect sequence recognition.

Paramagnetic NMR study of Cu(2+)-IDA complex localization on a protein surface and its application to elucidate long distance information.

The paramagnetic metal chelate complex Cu(2+)-iminodiacetic acid (Cu(2+)-IDA) was mixed with ubiquitin, a small globular protein. Quantitative analyses of (1)H and (15)N chemical shift changes and line broadenings induced by the paramagnetic effects indicated that Cu(2+)-IDA was localized to a histidine residue (His68) on the ubiquitin surface. The distances between the backbone amide proton and the Cu(2+) relaxation center were evaluated from the proton transverse relaxation rates enhanced by the paramagnetic effect.