Structure and Complexation Studies on 2,2′-Bipyridyl and Trivalent Lanthanides

Separation of trivalent lanthanides (Ln) and trivalent actinides (An) is important task in reprocessing high-level liquid waste. In this study, the relationship between structures of complexes of 2,2′-bipyridyl (Bpy) and Ln (Nd, Er) and coordination strengths were investigated by X-ray diffraction and UV titration. With the decrease in ionic radius from Nd to Er, the N(Bpy)-Ln distance and N(Bpy)-Ln-N(Bpy) angle decreased, the dihedral angle of the Bpy pyridines increased, and the stability constant increased. This information about structure and coordination strength is important for designing better ligands for separating Ln and An ions.     

The effects of free amino acids,nucleic compounds,and volatile constituents of funazushi (fermented sushi of crucian carp (Cyprinus auratus)) on preference

BACKGROUND: Funazushi is a fermented sushi containing n3 polyunsaturated fatty acids. Moreover, the functionality of lactic acid fermentation foods has come to be expected. Funazushi is therefore worthy of study. Funazushi has a specific flavor which is either strongly liked or strongly disliked. We examined the components of funazushi and investigated their relation to preference. RESULTS: Many free amino acids with sweetness and/or umami were present in funazushi, but nucleic compounds were scarce as taste elements. Twelve kinds of volatile elements were detected in all samples, which were thought to form the basis of the flavor of funazushi, although a total of 30 or more kinds of volatile elements were detected from each sample. The smell greatly influenced the overall evaluation. Panelists who had not eaten funazushi before, or only rarely, showed a tendency to prefer the same sample, from which ketones, aldehydes, or acids did not volatilize so much. On the other hand, individual variation was large among panels who commonly ate funazushi. CONCLUSION: The smell and sourness of funazushi greatly influenced preference, especially in persons who had little experience of eating funazushi. Funazushi containing low ketone, aldehyde, or acid levels is suitable for the first eating experience. Copyright © 2008 Society of Chemical Industry     

Carbon Stable Isotope Analysis for Glucose in Sake: Simple Freeze-Dried Sake Can Substitute for Glucose Following HPLC Isolation

Carbon stable isotope analysis of ethanol is an established method for determining the authenticity of alcoholic beverages, but there is no accepted method for measurements of glucose carbon stable isotopic composition (δ ¹³C). This study aims to establish two methods to determine accurately the δ ¹³C value of glucose isolated from sake by high-performance liquid chromatography (HPLC) after three clean-up steps using ion exchange chromatography and in simple freeze-dried sake (total nonvolatile matter) and to examine two methods that yield different δ ¹³C values. In the glucose isolation procedure, the δ ¹³C values of glucose were not significantly affected by the glucose concentration, solvent (water or aqueous acetonitrile), drying method (freeze-dry or nitrogen-spraying), the clean-up step using ion exchange chromatography (weakly acidic cation-exchange, strongly acidic cation-exchange, and weakly basic anion-exchange resins), or HPLC isolation. Glucose nitrogen spray-dried after isolation by ion exchange chromatography and HPLC showed a carbon isotope discrimination value of <0.1 ‰. The glucose δ ¹³C values ranged from ?26.8 to ?25.5 ‰ in authentic sake and from ?27.0 to ?11.0 ‰ in commercial sake samples. This HPLC isolation approach may provide a first step toward visualizing the brewing process via isotopic carbon flow during fermentation. Additionally, there was no significant difference between the δ ¹³C values of glucose and total nonvolatile matter from sake. The δ ¹³C measurement of simple freeze-dried sake can substitute for glucose δ ¹³C measurement using HPLC isolation, thus aiding high-throughput detection of carbon derived from C₄ plants in sake.     

Uromodulin Regulates Murine Aquaporin−2 Activity via Thick Ascending Limb–Collecting Duct Cross−Talk during Water Deprivation

Uromodulin, a urinary protein synthesized and secreted from the thick ascending limb (TAL) of the loop of Henle, is associated with hypertension through the activation of sodium reabsorption in the TAL. Uromodulin is a potential target for hypertension treatment via natriuresis. However, its biological function in epithelial cells of the distal nephron segment, particularly the collecting duct, remains unknown. Herein, we examined the regulation of uromodulin production during water deprivation in vivo as well as the effect of uromodulin on the activity of the water channel aquaporin−2 (AQP2) in vitro and in vivo using transgenic mice. Water deprivation upregulated uromodulin production; immunofluorescence experiments revealed uromodulin adhesion on the apical surface of the collecting duct. Furthermore, the activation of AQP2 was attenuated in mice lacking uromodulin. Uromodulin enhanced the phosphorylation and apical trafficking of AQP2 in mouse collecting duct cells treated with the vasopressin analog dDAVP. The uromodulin-induced apical trafficking of AQP2 was attenuated via endocytosis inhibitor treatment, suggesting that uromodulin activates AQP2 through the suppression of endocytosis. This study provides novel insights into the cross−talk between TAL and the collecting duct, and indicates that the modulation of uromodulin is a promising approach for diuresis and hypertension treatment.     

Synthesis and properties of superabsorbent hydrogels based on guar gum and succinic anhydride

Synthesis of novel superabsorbent hydrogels has been investigated with the reaction of guar gum and succinic anhydride (SA), using of 4‐dimethylaminopyridine as esterification promoter and water or dimethylsulfoxide (DMSO) as reaction solvent, followed by NaOH neutralization. Hydrogels prepared in water exhibited somewhat higher water absorbency than those prepared in DMSO; its maximum water absorbency in pure water and aqueous 0.9% NaCl solution was ca. 200 g/g and 80 g/g, respectively. These values were considerably higher than those of hydrogels obtained from starch in a similar way. The products in this study biologically degraded up to 70–80% after 10 days in activated sludge, which shows their excellent biodegradability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Two-dimensional spin-exchange solid-state NMR study of the crystal structure of cellulose II

A two-dimensional (2D) ¹³C-¹³C spin-exchange NMR experiment was applied to the uniformly ¹³C-enriched cellulose II in order to obtain interatomic distance information in the cellulose II crystal. A radio frequency-driven recoupling (RFDR) rotor-synchronized π pulse sequence was incorporated during the mixing time of the 2D experiment. The 2D spin-exchange NMR recorded with a short mixing time (0.80-2.58 ms) provided the correlations between a pair of strongly coupled ¹³C spins such as neighbor carbon nuclei. This spectrum enabled us to assign all ¹³C resonance lines of two kinds of anhydroglucose residues A and B in the structure of cellulose II. On the basis of the ¹³C resonance assignment of residues A and B, the interatomic distances from each C1 to the other carbon nuclei were compared by measuring the 2D spectra recorded with longer mixing times (5.12-20.48 ms). As a result, it was revealed that the respective residues A and B are composed of independent chains (-A-A- and -B-B- repeating units) and that there are no -A-B- repeating units in the chain. This experimental technique is expected to be applicable to conformation analysis of polysaccharides as well as the other cellulose polymorphs.     

Hidden Markov model-based prediction of antigenic peptides that interact with MHC class II molecules

Elucidating the interaction between major histocompatibility complex (MHC) molecules and antigenic peptides is fundamental to better understanding of the processes involved in immune responses and for the development of innovative immunotherapies. In the present study, hidden Markov models (HMM) were combined with the successive state splitting (SSS) algorithm for optimization of the HMM structure, to predict peptide binders to the human MHC class II molecule HLA-DRB1*0101. The predictive performance of our model (S-HMM) was compared with fully connected HMM and artificial neural network (ANN) methods using the relative operating characteristic (ROC) analysis. The S-HMM predictions had values of ROC > or = 0.85 which was at least as good, or better than the comparison methods. In addition, S-HMM is trained on positive data only and does not require exhaustive data preprocessing, such as peptide alignment. Our results demonstrated that S-HMM combines the high accuracy of predictions with the simplicity of implementation and is therefore useful for analyzing MHC class II binding peptides. In particular the S-HMM may be trained using only positive data and, the preprocessing of training data, such as peptide alignment and the selection of binding cores, is not required in this method.     

Fabrication of high-power electric double-layer capacitors

The electrochemical behavior of activated carbon/carbon (AC/C) composite electrodes was investigated for high-power electric doublelayer capacitors (EDLCs). It was found that high-rate charge/discharge characteristics are affected by the resistance of the electrolyte phase in the pores of the electrode. The charge/discharge characteristics were improved by optimizing the pore-size distribution of the electrodes. The size and total volume of the macro-pores in the electrodes were controlled by mixing and burning out polymer spheres. A high-power EDLC (15V, 470 F), which can discharge as much as 500 A, was fabricated by using improved AC/C composite electrodes.     

Analysis of a 36·2 kb DNA sequence including the right telomere of chromosome VI from Saccharomyces cerevisiae

The nucleotide sequence of a 36·2-kb distal region containing the right telomere of chromosome VI was determined. Both strands of DNA cloned into cosmid clone 9965 and plasmid clone pEL174P2 were sequenced with an average redundancy of 7·9 per base pair, by both dye primer and dye terminator cycle sequencing methods. The G + C content of the sequence was found to be 37·9%. Eighteen open reading frames (ORFs) longer than 100 amino acids were detected. Four of these ORFs (9965orfR017, 9965orfF016, 9965orfR009 and 9965orfF003) were found to encode previously identified genes (YMR31, PRE4, NIN1 and HXK1, respectively). Six ORFs (9965orfR013, 9965orfF018, 9965orfF006, 9965orfR014, 9965orfF013 and 9965orfR020) were found to be homologous to hypothetical 121·4-kDa protein in the BCK 5′ region, Bacillus subtilis DnaJ protein, hypothetical Trp-Asp repeats containing protein in DBP3-MRPL27, putative mitochondrial carrier YBR291C protein, Salmonella typhimurium nicotinate-nucleotide pyrophosphorylase, and Escherichia coli cystathionine β-lyase, respectively. The putative proteins encoded by 9965orfF018, 9965orfR014 and 9965orfR020 were found to be, respectively, a new member of the family of DnaJ-like proteins, the mitochondrial carrier protein and cystathionine lyase. The nucleotide sequence reported here has been deposited in the DDBJ/GenBank/EMBL data library under Accession Number D44597.