Axial chirality in biaryl N,N-dialkylaminopyridine derivatives bearing an internal carboxy group

Axial chirality in N,N-dimethylaminopyridines as well as N,N-dipropylaminopyridines bearing an internal carboxy group were evaluated based on their racemization barriers and circular dichroism spectra. The half-life of racemization of N,N-dipropylaminopyridine derivative 2 was estimated to be 19.7 days at 20°C. Its enantiomers isolated as optically active forms showed positive-negative and negative-positive Cotton effects for (+)- 2 and (−)- 2 , respectively, from 310 to 210 nm. Furthermore, (−)- 2 was applied as a chiral nucleophilic catalyst and exhibited asymmetric induction in acylative kinetic resolution of 1-(1-naphthyl)ethane-1-ol.     

Enhanced skeletal muscle glycogen repletion after endurance exercise is associated with higher plasma insulin and skeletal muscle hexokinase 2 protein levels in mice: comparison of level running and downhill running model

Journal of Physiology and Biochemistry - To identify factors that influence post-exercise muscle glycogen repletion, we compared the glycogen recovery after level running with downhill running, an...     

Comparison of Barium and Arsenic Concentrations in Well Drinking Water and in Human Body Samples and a Novel Remediation System for These Elements in Well Drinking Water

Health risk for well drinking water is a worldwide problem. Our recent studies showed increased toxicity by exposure to barium alone (≤700 µg/L) and coexposure to barium (137 µg/L) and arsenic (225 µg/L). The present edition of WHO health-based guidelines for drinking water revised in 2011 has maintained the values of arsenic (10 µg/L) and barium (700 µg/L), but not elements such as manganese, iron and zinc. Nevertheless, there have been very few studies on barium in drinking water and human samples. This study showed significant correlations between levels of arsenic and barium, but not its homologous elements (magnesium, calcium and strontium), in urine, toenail and hair samples obtained from residents of Jessore, Bangladesh. Significant correlation between levels of arsenic and barium in well drinking water and levels in human urine, toenail and hair samples were also observed. Based on these results, a high-performance and low-cost adsorbent composed of a hydrotalcite-like compound for barium and arsenic was developed. The adsorbent reduced levels of barium and arsenic from well water in Bangladesh and Vietnam to <7 µg/L within 1 min. Thus, we have showed levels of arsenic and barium in humans and propose a novel remediation system.     

RNAi suppression of β-N-acetylglucosaminidase (BmFDL) for complex-type N-linked glycan synthesis in cultured silkworm cells

Glycoproteins have various biological functions including enzymatic activity, protein stability and others. Due to the presence of paucimannosidic N-linked glycans, recombinant proteins from an insect cell expression system may not be suitable for therapeutic use. Because baculovirus expression systems (BESs) are used to produce recombinant proteins, it is of interest to modify the endogenous N-glycosylation pathway in insects to mimic that of mammals. Using a soaking RNAi sensitive cell line, BmN4-SID1, has enabled us to suppress Bombyx mori FDL (BmFDL), an N-linked glycan-specific β-N-acetylglucosaminidase. Western blotting and MALDI-TOF MS demonstrated that the BmFDL depletion almost completely converted the paucimannosidic structures of the recombinant proteins produced by BES into a complex-type structure. This highly efficient, simple and low-cost method can be used for mass production of secretion proteins with complex-type N-linked glycans.     

Colorimetric/fluorogenic detection of thiols by N-fused porphyrin in water

A water-soluble derivative of N-fused porphyrin (NFP) possessing four cationic side-arms (pPyNFP) serves as a unique class of colorimetric/fluorogenic reporters that selectively react with biothiols in aquaous media to afford N-confused porphyrin (NCP) derivatives, while other nucleophilic amino acids were inert under a wide range of pH conditions. Owing to the large difference of the optical properties between NCP and NFP, the transformation enabled selective detection of biothiols in colorimetric/fluorogenic manner, especially in the near-infrared region. To the best our knowledge, this is the first example of porphyrin-based thiol detection systems that use the direct attack of thiol group on the optical reporter.     

Studies on the Pungent Principle of Capsicum

The chemical constitutions of the pungent principle of Capsicum were investigated. These principles are assumed to consist of capsaicin, dihydrocapsaicin, nordihydrocapsaicin, homodihydrocapsaicin and two or more analogues of these materials. Thin-layer chromatography and open tubular gas chromatography showed that the natural pungent mixture contains no cis-isomer of capsaicin. The chemical structure of nordihydrocapsaicin was determined as N-(4-hydroxy-3-methoxybenzyl)-7-methyloctanamide by gas chromatography, infrared spectroscopy, mass spectrometry and nuclear magnetic resonance spectroscopy. In addition, homodihydrocapsaicin was identified as N-(4-hydroxy-3-methoxybenzyl)-9-methyl-decanamide. These identities were also proven by comparison with synthetic samples.     

4-Aryl-5-carbamoyl-3-isoxazolols as competitive antagonists of insect GABA receptors: Synthesis,biological activity,and molecular docking studies

Competitive antagonists (CAs) of ionotropic GABA receptors (GABARs) reportedly exhibit insecticidal activity and have potential for development as novel insecticides for overcoming emerging resistance to traditional GABAR-targeting insecticides. Our previous studies demonstrated that 4,5-disubstituted 3-isoxazolols or 3-isothiazolols are an important class of insect GABAR CAs. In the present study, we synthesized a series of 4-aryl-5-carbamoyl-3-isoxazolols and examined their antagonism of insect GABARs expressed in Xenopus oocytes. Several of these 3-isoxazolols exhibited potent antagonistic activities against housefly and common cutworm GABARs, with IC₅₀ values in the low-micromolar range in both receptors. 4-(3-Amino-4-methylphenyl)-5-carbamoyl-3-isoxazolol (3u) displayed the highest antagonism, with IC₅₀ values of 2.0 and 0.9?μM in housefly and common cutworm GABARs, respectively. Most of the synthesized 3-isoxazolols showed moderate larvicidal activities against common cutworms, with more than 50% mortality at 100?μg/g. These results indicate that 4-monocyclic aryl-5-carbamoyl-3-isoxazolol is a promising scaffold for insect GABAR CA discovery and provide important information for the design and development of GABAR-targeting insecticides with a novel mode of action.     

Possible adaptive and non-adaptive radiation in three plant genera in the Japanese archipelago

The adaptive radiation of flowering plants as manifested by the floral diversity has long been considered associated with the diversity of plant–pollinator interactions, because changes in plant–pollinator interactions are hypothesized as one of the major mechanisms driving plant ecological speciation. To understand the relative contributions of various mechanisms for plant radiation, including pollinator changes, it is useful to study a plant group for which comparative study of the species life history across the whole lineage is feasible. To this end, we will focus on the plant lineages that have presumably radiated in the Japanese archipelago, namely, the genera Asimitellaria, Asarum, and Arisaema. By comparing these three genera, we will comment on the possible modes of adaptive radiation and diversification among the endemic flora of Japan.     

Opposing pharmacological actions of cepharanthin on lipopolysaccharide-induced histidine decarboxylase activity in mice spleens

A biscoclaurin alkaloid preparation, cepharanthin (Ceph), is reported to have opposing pharmacological effects, enhancement or depression, on several cells and tissues, although detailed mechanisms remain unclear. Previously, we reported that Ceph enhanced lipopolysaccharide (LPS)-induced histidine decarboxylase (HDC) activity in mice spleens by consecutive pre-administration. In this study, we examined the pharmacological effects on HDC activity of a single Ceph pre-administration to test the influence of the administration method. Consequently, HDC activities were decreased by a single administration 15 minutes before LPS challenge in ddY and ICR mice spleens. Moreover, to further examine this suppressing effect, we employed genetically mast cell-deficient WBB6F1 W/Wv (W/Wv) mice to avoid the influence of mast cells. In W/Wv mice, HDC activity was enhanced, but not in the congenic WBB6F1 +/+ mice. These findings suggest that mast cells influence the depressant effect on HDC activity by a Ceph single administration in mast cell sufficient mice.