Humidity-Induced Switching between Two Magnetic and Structural Phases in a CoII-[WV(CN)8] Molecular Magnet

The self-assembly of cobalt(II) with purine and octacyanidotungstate(V) results in the formation of the three-dimensional Co₃[W(CN)₈]₂(purine)₂ ⋅ 8.5H₂O ( 1 ) coordination polymer. This compound exhibits humidity-induced variation of the number of water molecules of crystallisation leading to a reversible structural phase transition and the alternation of the long-range ferromagnetic ordering temperature from T_C=29 K for the pristine assembly ( 1 ) to T_C=49 K for the sample stored in a low-humidity atmosphere ( 1-deh ). This phenomenon can be attributed to a reversible change in the hydrogen-bonding network resulting in the modification of the local geometries of cobalt(II) as well as the cyanido bridges.     

2-Naphthol Moiety of Neocarzinostatin Chromophore as a Novel Protein-Photodegrading Agent and Its Application as a H2O2-Activatable Photosensitizer

A 2-naphthol derivative 2 corresponding to the aromatic ring moiety of neocarzinostatin chromophore was found to degrade proteins under photo-irradiation with long-wavelength UV light without any additives under neutral conditions. Structure–activity relationship studies of the derivative revealed that methylation of the hydroxyl group at the C2 position of 2 significantly suppressed its photodegradation ability. Furthermore, a purpose-designed synthetic tumor-related biomarker, a H₂O₂-activatable photosensitizer 8 possessing a H₂O₂-responsive arylboronic ester moiety conjugated to the hydroxyl group at the C2 position of 2 , showed significantly lower photodegradation ability compared to 2 . However, release of the 2 from 8 by reaction with H₂O₂ regenerated the photodegradation ability. Compound 8 exhibited selective photo-cytotoxicity against high H₂O₂-expressing cancer cells upon irradiation with long-wavelength UV light.     

Palladium-free zinc-mediated hydroamination of alkynes: efficient synthesis of indoles from 2-akynylaniline derivatives

Reaction of 2-phenylethynyl N-tosylanilide prepared by Pd-free procedure with ZnBr₂ (3 equiv) in refluxing toluene gave N-tosyl-2-phenylindole in 93% yield. Treatment of 2-phenylethynylaniline with ZnBr₂ (1 equiv) in refluxing toluene resulted in the formation of 2-phenylindole in 91% yield. Catalytic ZnBr₂ (0.05 equiv) effectively reacted with 2-alkynylanilines to afford 2-substituted indoles in high yields. Thus, complete Pd-free zinc catalyzed hydroamination of 2-alkynylanilines was achieved.     

Arsenic accumulation by arsenic-tolerant freshwater blue-green alga (Phormidium sp.)

Accumulation, biomethylation and excretion of arsenic by the arsenic-tolerant freshwater blue–green alga, Phormidium sp., which had been isolated from an arsenic-polluted environment, were investigated. The cellular growth curves were in fair agreement with a ‘logistic curve’ equation. The growth increased with an increase in the surrounding arsenic concentration up to 100 m?g g^?1. The cells survived even at 7000 m?g g^?1. The arsenic concentration of the cells increased with an increase of the surrounding arsenic concentration up to 7000 m?g g^?1. Phosphorus concentrations in the medium affected the growth and arsenic accumulation. No arsenic was accumulated by cells killed by ethanol. The arsenic was methylated to the extent of 3.2% of the total arsenic accumulated. When the cells were transferred into an arsenic-free medium, 85% of the arsenic accumulated was excreted; 58% of the excreted arsenic was in methylated form implying extensive methylation in the arsenic-free medium.     

Direct measurement of isotopomer of intracellular metabolites using capillary electrophoresis time-of-flight mass spectrometry for efficient metabolic flux analysis

We have developed a metabolic flux analysis method that is based on (13)C-labeling patterns of the intracellular metabolites directly measured by capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). The flux distribution of the central carbon metabolism in Escherichia coli was determined by this new approach and the results were compared with findings obtained by conventional GC-MS analysis based on isotopomer of the proteinogenic amino acids. There were some differences in estimation results between new approach using CE-TOFMS and conventional approach using GC-MS. These were thought to be attributable to variations in measured mass distributions between amino acids and the corresponding precursors and to differences in the sensitivity of the exchange coefficients to mass distributions. However, our CE-TOFMS method facilitates high-throughput flux analysis without requiring complicated sample preparation such as hydrolysis of proteins and derivatization of amino acids.     

Effect of high hydrostatic pressure on enzyme activity in unpasteurized draft sake

ABSTRACT

Unpasteurized draft sake has a potentially high market value, due to its fresh flavor and fruity taste, compared with conventional thermal-pasteurized sake. However, the shelf life of draft sake is limited. To increase the shelf life of draft sake, it is necessary to suppress flavor and taste deterioration resulting from inactivation of enzymes produced by koji-mold. Draft sake was treated with high hydrostatic pressure (HHP) of 200 to 500?MPa at ?7 to 50°C to analyze the inactivation of α-amylases, glucose-forming enzymes, and acid carboxypeptidases. We found significant inactivation of enzymes produced by koji-mold in draft sake subjected to HHP treatment at both high and low temperature. However, HHP treatment at low temperature effectively inactivated enzymes while retaining the fresh flavor and fruity taste of draft sake.     

High hydrostatic pressure pasteurization of a draft sake brewed using a Niigata-sake yeast

ABSTRACT

Draft (non-pasteurized) sake typically has a fresh flavor, but usually has to be consumed as soon as possible because of its short shelf life due to the potential for over-fermentation by residual yeast. In contrast, thermally pasteurized sake has a long shelf life, but the fresh flavor is lost during heat sterilization. High hydrostatic pressure (HHP) treatment can be used as a non-thermal pasteurization process while maintaining the characteristics of a draft sake. We evaluated the HHP inactivation behavior of sake yeast for the application of HHP pasteurization as an alternative to thermal pasteurization. The results showed complete pasteurization of sake yeast in the draft sake by HHP treatment at 400?MPa for 10?min. The viable cell count in HHP-pasteurized sake was below the detection limit during storage at 10°C for 3 months. Thus, we have established a HHP pasteurization technology to prevent over-fermentation and succeeded in producing a prototype of HHP-sparkling-cloudy sake, which we have designated AWANAMA.     

Novel protection of 1,2-diol for trans-dihydroxycyclopentene ring construction by the CH insertion of alkylidene carbene: Formal total synthesis of (+)-trehazolin

The chiral vicinal diol was protected as 6-methylene-1,4-dioxepane to construct a cyclopentene ring by the CH insertion of alkylidene carbene. The removal of the protecting group was achieved in a few steps, affording the corresponding diol in a reasonable yield. Using these reactions, the known synthetic intermediate for (+)-trehazolin was synthesized from d-diethyl tartrate. In addition, a short route to the intermediate from a d-mannitol derivative was described.