Brewing characteristics of piezosensitive sake yeasts

Application of high hydrostatic pressure (HHP) treatment to food processing is expected as a non-thermal fermentation regulation technology that supresses over fermentation. However, the yeast Saccharomyces cerevisiae used for Japanese rice wine (sake) brewing shows high tolerance to HHP. Therefore, we aimed to generate pressure-sensitive (piezosensitive) sake yeast strains by mating sake with piezosensitive yeast strains to establish an HHP fermentation regulation technology and extend the shelf life of fermented foods. The results of phenotypic analyses showed that the generated yeast strains were piezosensitive and exhibited similar fermentation ability compared with the original sake yeast strain. In addition, primary properties of sake brewed using these strains, such as ethanol concentration, sake meter value and sake flavor compounds, were almost equivalent to those obtained using the sake yeast strain. These results suggest that the piezosensitive strains exhibit brewing characteristics essentially equivalent to those of the sake yeast strain.     

Erratum: Release of enzyme strain during catalysis reduces the activation energy barrier

In the aforementioned article, the wrong version of the first paragraph in the section entitled “ Quantitative Analysis of the Relationship between the Torsion and pK_a of the PLP‐Lys258 Aldimine ” was printed. Please find the correct version printed below. We apologize to our readership and the authors for this regrettable error.     

New bronchodilators. II. 3H-imidazo[4,5-c]quinolin-4(5H)-ones.

A series of novel 3-substituted imidazo[4,5-c]quinolin-4(5H)-ones (2a-w) was prepared by the reaction of imidazo[4,5-c]quinolin-4(5H)-ones (6) with several electrophiles under basic conditions. The bronchodilatory activity of these compounds was evaluated on the basis of their protective effects against antigen-induced contraction (the Schultz-Dale reaction) of guinea-pig trachea (in vitro) and antigen inhalation-induced bronchospasm in passively sensitized guinea-pigs (in vivo). Although correlations between in vitro and in vivo activities were not clear, short alkyl chains such as the methyl and ethyl groups at the 3-position were important for potent activity, especially in vivo. Substituents at the 5-position were more tolerant of the activity than those at the 3-position. 5-Ethyl-3-methyl-3H-imidazo[4,5-c]quinolin-4(5H)-one (21) exhibits the most potent bronchodilatory activity among our tested compounds and is at least 5-fold more active than theophylline in vivo.     

Microwave spectrum of two top molecules in the excited states dimethyl ether, dimethyl sulfide, and dimethyl silane

Microwave spectra of dimethyl ether, dimethyl sulfide, and dimethyl silane in the torsionally excited states have been measured. The methyl internal rotations of these molecules were analyzed from the observed multiplets and from the reported multiplets of transitions. The method developed for ethyl silane in the previous paper was extended to equivalent two top molecules. For equivalent two top molecules, apparent barriers of methyl internal rotations obtained from the experiments were corrected by the kinetic and potential cross terms. They are V₃=2645.8±10.0, 2632.4 ± 42.9, 2146.0 ± 13.8, 1651.5 ± 10.1, 1648.0 ± 13.7, and 1649.9 ± 11.8 cal/mol for (CH₃)₂O, (CD₃)₂O, (CH₃)₂S, (CH₃)₂SiH₂, (CH₃)₂SiD₂, and (CH₃)₂SiHD, respectively. The potential cross terms, V₁₂(1−cos3α₁)(1−cos3α₂) terms are negligible for the three molecules, while V^′₁₂sin3α₁sin3α₂ terms are also very close to zero except those for (CH₃)₂O and (CD₃)₂O which are small but not negligible (V^′₁₂=−124.4,−158.0 cal/mol). The investigations were extended to those of non-equivalent two top species and the corrected barriers of the methyl tops, V₃, are obtained to be 2615.6 ± 8.6 and 2155.0 ± 15.2 cal/mol for CH₃OCD₃ and CH₃SCD₃. The corrected barrier, V₃(CD₃) of CH₃OCD₃, is obtained to be 2634.4 ± 7.1 cal/mol, while that of CH₃SCD₃ cannot be solved due to the lack of the data available.     

Syntheses and properties of 3-acylimino-1-alkylimidazolium and benzimidazolium betaines

3-Amino-1-alkylimidazolium and benzimidazolium mesitylenesulfonates were readily prepared in good to high yeilds by treating the parent heterocycles with O-mesitylenesulfonylhydroxylamine. Treatment of the 3-amine salts with acylating agents gave crystalline 3-acylimines, which showed the characteristic ir, uv, nmr, and mass spectral properties. Deuterium exchange of the 3-acylimines occurs at the 2-position. Thermolysis of neat 3-benzoylimino-1-rnethylbenzimidazolium betaine afforded 2-benzamido-1-methylbenzimidazole and products derived from N? N bond cleavage. Irradiation of 3-benzoylimino-1-alkylbenzimidazoliurn betaines resulted in N? N bond cleavage to give 1-alkylbenzimidazoles and benzamide, while the corresponding 3-ethoxycarbonylimines underwent rearrangement to afford ethyl 1-alkyl-2-benzimidazolecarbamates.     

Photoluminescence spectra of clusters of group IV elements embedded in SiO2 matrices

Using a rf co-sputtering technique, SiO₂ films containing C, Si and Ge atoms were prepared and their Raman and photoluminescence spectra were measured. Raman spectra obtained are very broad indicating that the group IV elements are embedded in the form of clusters. The samples containing C clusters showed a very strong photoluminescence peak at around 2.1～2.2eV (visible with naked eye). The films containing Ge and Si clusters showed luminescence peaks at around 1.6～1.8eV. Strong luminescence was not observed for the samples containing well grown microcrystals a few nanometers in diameter.