Effect of lignophenol on allergen mitigation

The deactivating of mite allergens was investigated using lignophenols, which are polymers with a light-beige appearance that were synthesized directly from lignocellulose with a phase-separation system. Various applications of lignophenols, instead of the photochemical solar cell dye-sensitized with lignophenol, have been reported. In the present study, lignophenols were applied for the deactivation of mite allergens.     

Novel peptides bearing pyrene and coumarin units with or without beta-cyclodextrin in their side chains exhibit intramolecular fluorescence resonance energy transfer

Novel peptides bearing the pyrene/coumarin FRET pair in their side chains have been designed and synthesized. Peptide 1 having endogenous beta-cyclodextrin (beta-CD) in the side chain exhibits FRET in aqueous solution, indicating that coumarin, being accommodated into the CD cavity, is separated from pyrene. Guest-induced quenching of the fluorophores in 1 indicates that coumarin, being excluded from the CD cavity, comes into close contact with pyrene. Peptide 2 shows FRET only after addition of external beta-CD that again reflects the idea that beta-CD surely caps the coumarin unit in its hydrophobic cavity, and, therefore, quenching of the fluorophores can be prevented in FRET peptide probes. With this strategy, various peptide-based FRET probes can be developed that would be useful for studying biological phenomena in living cells.     

Mononuclear and dinuclear monoperoxovanadium(v) complexes with a hetero ligand. 1.(1) Self-decomposition reaction, detection of reactive oxygen species, and oxidizing ability

A mononuclear peroxovanadium(V) complex with histamine-N,N-diacetate (histada), K[VO(O(2))(histada)], and a dinuclear peroxovanadium(V) complex with 2-oxo-1,3-diaminopropane-N,N,N',N'-tetraacetate (dpot), Cs(3)[(VO)(2)(O(2))(2)(dpot)], were prepared and characterized. The self-decomposition reaction was examined for these peroxovanadium(V) complexes as well as for K[VO(O(2))(cmhist)] (cmhist = N-carboxymethylhistidinate). The reaction profiles depicted by the absorbance change in the UV-vis spectrum show a sigmoid shape with an induction period. The induction period is reduced by the addition of acid, fluoride, thiocyanate, VO(2+), VO(2)(+), and trolox compared to the solution containing perchlorate. On the other hand, the induction period was elongated by the addition of chloride, bromide, and 2-tert-butyl-p-cresol. These behaviors are discussed on the basis of a radical chain mechanism. The self-decomposition reactions have also been followed by the (1)H and (51)V NMR and EPR spectra. These spectral studies as well as the UV-vis spectral study indicate that vanadium(V) is partly reduced to vanadium(IV) in the self-decomposition process. The histada complex yields a mixed-valence dinuclear complex in a concentrated solution, and the dpot complex yields a mixed-valence tetranuclear complex. The reduction of vanadium ion suggests that the peroxo ligand may act as a reducing agent. In order to know the fate of the peroxo ligand, we tried to detect superoxide anion and hydroxyl radical, which were anticipated to be produced in the self-decomposition process. The formation of superoxide anion was spectrophotometrically confirmed using two independent methods, including the reduction of cytochrome c and the reduction of sodium 4-[3-(iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate (WST-1). The formation of hydroxyl radical was confirmed by an EPR spin trapping technique. The oxidizing abilities of the peroxovanadium(V) complexes toward bovine serum albumin (BSA) were also evaluated. In the protein carbonyl assay, it was found that the total amount of protein carbonyl in BSA was increased by the reaction with the peroxovanadium complexes in the concentration-dependent manner. In addition, the oxidation of sulfhydryl group in BSA induced by the peroxovanadium complexes was confirmed.     

Catalytic Asymmetric Phase‐Transfer Michael Reaction and Mannich‐Type Reaction of Glycine Schiff Bases with Tartrate‐Derived Diammonium Salts

Catalytic asymmetric Michael and Mannich‐type reactions of glycine Schiff bases with chiral two‐center organocatalysts, tartrate‐derived diammonium salts (TaDiASs), are described. On the basis of conformational studies, optimized TaDiASs with a 2,6‐disubstituted cyclohexane spiroacetal were newly designed. These TaDiASs catalyzed the asymmetric Michael and Mannich‐type reactions of glycine Schiff bases with higher enantioselectivity than previous catalysts. In the Mannich‐type reaction, aromatic N‐Boc‐protected imines (Boc=tert‐butoxycarbonyl) as well as enolizable alkyl imines were applicable. As a synthetic application of the catalytic asymmetric Mannich‐type reaction with the optimized TaDiASs, we developed a catalytic asymmetric total synthesis of (+)‐nemonapride, which is an antipsychotic agent.     

Isolation of new eremophilane-type sesquiterpenoids, subspicatins A-D and subspicatolide from Ligularia subspicata, and chemical and genetic diversity of the species

New C-1 oxidized eremophilane-type sesquiterpenoids, subspicatins A, B, C, and D, and subspicatolide, were isolated from the root of Ligularia subspicata and their structures were established by spectroscopic and X-ray analyses. Subspicatins A and B were the major components. The species were found to be diverse both in the composition of the root chemicals and in the nucleotide sequences of the internal transcribed spacers (ITS) of the ribosomal RNA gene and the atpB-rbcL intergenic region, but the difference among the samples was not distinct but continuous.     

Sign of the quadrupole moment of proton drip-line nucleus 8B

The sign of the quadrupole coupling constant eqQ of ⁸B in ZrB₂ is determined to be positive through the β-delayed α-ray anisotropy measurement combined with the spin manipulation technique by use of the β-NMR. According to the theoretical calculation of the electric field gradient in ZrB₂, the sign of the quadrupole moment of ⁸B is deduced to be positive. This revised version was published online in August 2006 with corrections to the Cover Date.     

Heck-type 5-endo-trig cyclization promoted by vinylic fluorines: synthesis of 5-fluoro-3H-pyrroles

A 5-endo-trig alkene insertion proceeds under palladium catalysis via aminopalladium species starting from 3,3-difluoroallyl ketone O-pentafluorobenzoyloximes, providing a facile access to 5-fluoro-3H-pyrroles.     

Peptide arrays with designed α-helical structures for characterization of proteins from FRET fingerprint patterns

A practical high-throughput protein detection system is described, based on synthetic peptide arrays consisting of designed alpha-helical peptides, detected by fluorescence resonance energy transfer (FRET). Initially a model alpha-helical peptide known to interact with a structured protein, calmodulin, was selected to establish the strategy for high-throughput detection. In comparison to peptides with a single probe, a much higher FRET response has been observed with two fluorescent probes (7-diethylaminocoumarin-3-carboxylic acid and 5(6)-carboxy-fluorescein) at both termini of the synthetic peptides. To establish a reproducible high-throughput detection system, peptides were also immobilized onto a solid surface for detection of the target proteins. A small library of 112 different peptides was constructed, based on a model of the alpha-helical peptide with systematic replacement of residues carrying specific charges and/or hydrophobicities. The library was used to effectively characterize various proteins, giving their own 'protein fingerprint' patterns. The resulting 'protein fingerprints' correlate with the recognition properties of the proteins. The present microarray with designed synthetic peptides as the capturing agents is promising for the development of protein detection chips.     

Nuclear Spin Orientation Created in Heavy Ion Collisions and the Sign of the Q Moment of 13B

The momentum dependences of the nuclear spin polarization P and alignment A of ¹³B(, T _1/2 = 17.36 ms) produced in the 100A MeV ¹⁵N + Be collisions have been measured by detecting β-ray asymmetry. Because both the P and A were significantly smaller than the prediction from a simple kinematical model, some relaxation mechanisms must be take into account. Comparing the signs of the observed alignment of ¹²B, the sign of the quadrupole coupling constant eqQ of ¹³B in TiO₂ was determined to be positive.     

Complementary nucleobase interaction enhances peptide-peptide recognition and self-replicating catalysis

The availability of the complementary interaction of nucleobases for influencing the formation of peptide architectures was explored. Nucleobases were incorporated as additional recognition elements in coiled-coil peptides by employing nucleobase amino acids (NBAs), which are artificial L-alpha-amino gamma-nucleobase-butyric acids. The effect of the base-pair interaction on intermolecular recognition between peptides was evaluated through a self-replication reaction. The self-replication reactions of the peptides with complementary base pairs such as thymine-adenine or guanine-cytosine at the g-g' heptad positions were accelerated in comparison with those of the peptides with mismatched base pairs or without nucleobases. However, thymine-adenine pairs at the e-e' positions did not enhance the self-replication. In the presence of a denaturant, the enhancement effects of complementary base pairs on the reaction disappeared. Thermal denaturation studies showed that the thymine-adenine pairs contributed to stabilization of the coiled-coil structure and that the pairs at the g-g' positions were more effective than those at the e-e' positions. The peptide-peptide interaction was reinforced by complementary nucleobase interactions appropriately arranged in the peptide structure; these led to acceleration of the self-replication reactions.