Experimental and Theoretical Study for Core Excitation of Firefly Luciferin in Carbon K-Edge Spectra.

Carbon (C) K-edge X-ray absorption spectra for firefly luciferin were measured and assigned using time-dependent density functional theoretical calculations for luciferin anion and dianion to elucidate the effect of hydroxy-group deprotonation. It was found that the C K-edge spectra for luciferin had four characteristic peaks. The effect of deprotonation of the hydroxy group appears in the energy difference of the first and second peaks of these spectra. This energy difference is 1.0 eV at pH 7 and 2.3 eV at pH 10. The deprotonation of the hydroxy group can be distinguished based on the soft X-ray absorption spectra.

Crucial role of iron in epigenetic rewriting during adipocyte differentiation mediated by JMJD1A and TET2 activity.

Iron metabolism is closely associated with the pathogenesis of obesity. However, the mechanism of the iron-dependent regulation of adipocyte differentiation remains unclear. Here, we show that iron is essential for rewriting of epigenetic marks during adipocyte differentiation. Iron supply through lysosome-mediated ferritinophagy was found to be crucial during the early stage of adipocyte differentiation, and iron deficiency during this period suppressed subsequent terminal differentiation. This was associated with demethylation of both repressive histone marks and DNA in the genomic regions of adipocyte differentiation-associated genes, 　including Pparg, which encodes PPARγ, the master regulator of adipocyte differentiation. In addition, we identified several epigenetic demethylases to be responsible for iron-dependent adipocyte differentiation, with the histone demethylase jumonji domain-containing 1A and the DNA demethylase ten-eleven translocation 2 as the major enzymes. The interrelationship between repressive histone marks and DNA methylation was indicated by an integrated genome-wide association analysis, and was also supported by the findings that both histone and DNA demethylation were suppressed by either the inhibition of lysosomal ferritin flux or the knockdown of iron chaperone poly(rC)-binding protein 2. In summary, epigenetic regulations through iron-dependent control of epigenetic enzyme activities play an important role in the organized gene expression mechanisms of adipogenesis.

Absorption Spectra for Firefly Bioluminescence Substrate Analog: TokeOni in Various pH Solutions.

AkaLumine hydrochloride, named TokeOni, is one of the firefly luciferin analogs, and its reaction with firefly luciferase produces near-infrared (NIR) bioluminescence. Prior to studying the bioluminescence mechanism, basic knowledge about the chemical structures, electronic states, and absorption properties of TokeOni at various pH values of solution has to be acquired. In this paper, the absorption spectra for TokeOni and AkaLumine at pH 2-10 were measured. Density functional theory (DFT) calculations, time-dependent DFT calculations, and the vibrational analyses were carried out. The absorption spectra indicate that the chemical forms of TokeOni in solutions are same as those of AkaLumine. The peaks at pH 7-10 in the absorption spectra correspond to the excitation from the ground state of a carboxylate anion of AkaLumine, the peak at pH 2 corresponds to the excitation from the ground state of a carboxylate anion with an N-protonated thiazoline ring and N-protonated dimethylamino group of AkaLumine, and the peak at pH 4 corresponds to the excitation from the ground state of a carboxylate anion with an N-protonated thiazoline ring of AkaLumine.

Direct conversion of lignin to high-quality graphene-based materials via catalytic carbonization.

Methods for effectively utilizing lignin are necessary for the realization of a sustainable society. Herein, we report a method for directly converting lignin to graphene-based materials. Fe-supported lignin is prepared by dissolving lignin in an aqueous FeCl2 solution, followed by freeze drying. Graphene is then produced by catalytically carbonizing this Fe-supported lignin at 1200 °C. The characteristics of both the Fe catalyst and lignin are crucial for the production of high-quality graphene. Specifically, the lignin should disperse well in water, freeze dry, and carbonize via solid-state carbonization. The obtained graphene-based material is highly resistant to electrochemical oxidation, as observed in other graphene-based materials. The direct conversion of lignin to graphene described herein is an unprecedented method for synthesizing large amounts of graphene-based material at low cost, as well as being an excellent use for lignin.

Simultaneous capillary electrophoresis of anions and cations in a single injection using an anion exchanger-modified capillary for determination of salivary ions in combination with statistical analyses.

This paper describes the simultaneous capillary electrophoresis (CE) of anions and cations using an anion exchange-modified capillary, which was prepared by chemical coating with a cationic silylating reagent, and its application to saliva analysis. The CE method provides high-throughput (5 min for a single sample injection) analysis by generating a high-velocity electroosmotic flow at pH 3.0-3.5. The detection limits at a signal-to-noise ratio of 3 ranged from 1.2 to 18 µM for anions and 1.0 to 2.7 µM for cations. The relative standard deviations for the migration times and peak areas of analytes (n = 4) ranged from 0.05% to 0.40% and 0.94% to 4.7%, respectively. The CE system was used to analyze 11 common ions in saliva samples collected from long-distance runners and sedentary university students before and after running for a set distance or a set time. Interestingly, the SCN- concentrations decreased in the saliva samples of all 14 athletes and 16 sedentary students after running. Furthermore, when the concentrations of the analyzed ions were compared with that of cortisol as a typical stress marker by multiple regression analysis, SCN- and NO3- in saliva samples from the two subject groups strongly correlated with cortisol levels, as determined by an electrochemiluminescence immunoassay. This study improves our knowledge of both the analytical methodology for CE and statistical methods for identifying common ions that could be used as physical stress markers.

Variations in Cadmium Concentrations in Rice and Oxidation-Reduction Potential at the Soil Surface with Supplementation of Fermented Botanical Waste-based Amendment in Large-scale Farmland.

We monitored the relationship between the cadmium (Cd) concentration uptake of rice and the oxidation-reduction potential (ORP) at the soil surface with the supplementation of fermented botanical waste-based amendment (FBWA), an organic fertilizer prepared from woody and food wastes. This study was carried out for 3 years in the western part of Jiangsu Province, China. It was found that the Cd concentration taken up by rice was correlated to a decreased the ORP of the cultivated soil. The yield of rice was ∼1.20 times higher than that of the control plot. The effects of reducing the Cd content in rice and increasing the rice yield remained for 2 years after FBWA application. Finally, Cd was immobilized in the soil with adsorption to FBWA or the decomposed products. The ORP measurement during rice cultivation might be a key index to predict the suppression effect of Cd uptake into the rice or limitation of the sustainable effect by the FBWA.

Utilization of Anion-exchange Guard Column as an Ion Chromatographic Column of Anions Including Application to Simultaneous Separation of Anions and Cations.

This study demonstrated that a guard column containing anion-exchange resin has the potential for use as a separation column for acid eluent. Specifically, a 1-cm long anion-exchange guard column with a 4.6-mm internal diameter provided good separation of monovalent inorganic anions, by elution of 8 mM tartaric acid or 4 mM malic acid. Using the guard column with acid eluent could be applied to evaluation of nitrite and nitrate ions in mountain and urban river water samples. When the guard column was connected in front of a cation-exchange separation column (15 cm long × 4.6 mm internal diameter) in a series, the system provided simultaneous separation of anions and cations in eluent of 8 mM tartaric acid and 0.5 mM 18-crown-6 ether by a single injection.

Dynamic Four-step Sequential Extraction Procedure Using a Four-channel Circulating Flow System for Extracting Cd, Cu, Pb, and Zn from Solid Environmental Samples.

A method for extracting metals from solid samples was developed. The system had four flow channels (each containing a column packed with a solid sample), a single-flow peristaltic pump, and eight six-port valves. An extractant was passed into each channel for a specified period, then the valves were closed. We evaluated the system by performing a four-step sequential extraction procedure to extract heavy metals from a lake sediment sample. The four extractants were, in order of use, magnesium chloride, ammonium acetate, hydroxylamine hydrochloride, and hydrochloric acid. The concentrations of the analytes extracted agreed well with the concentrations determined using the batch method. The system was also successfully used to analyze heavy metals in a soil sample from a parking lot and fly ash from a domestic waste disposal facility. The total amount of extractant required per sample using the system was two-thirds of the amount required using the batch method.

Simultaneous suppression of magnetic nanoscale powder and fermented bark amendment for arsenic and cadmium uptake by radish sprouts grown in agar medium.

In this study, we effectively suppressed arsenic and cadmium uptake into a plant using magnetic nanoparticle powder (MNP) and fermented bark amendment (FBA) in agar medium. The MNP (which consists of FeO·Fe2O3) quantitatively adsorbed arsenite (As(III)) and the FBA (which mainly consists of bark waste) adsorbed cadmium, regardless of the pH. The properties of MNP and FBA in agar medium were compared based on the amounts of arsenic and cadmium in cultivated radish sprouts. While adding FBA selectively suppressed cadmium uptake by radishes, adding MNP suppressed the uptake of both arsenic and cadmium. Considering that the uptake of analytes was slightly reduced even in agar without any additives, the agar itself might also have contributed to the suppression of analyte uptake into plants. In addition, even when radish sprouts were cultivated in agar containing arsenic and cadmium (100 µg/L each) mixed with 25 g MNP and 1.25 g FBA per 25 mL agar, arsenic and cadmium absorption decreased by 90% and 82%, respectively, versus agar without additives. Furthermore, adding the mixed amendment to agar accelerated the growth of radishes, whereas MNP significantly inhibited radish growth even though it reduced analyte uptake. Our results indicated that mixing inorganic and organic adsorbents could simultaneously inhibit cadmium and arsenic uptake by plants and accelerate plant growth in the cadmium and arsenic-contaminated agar medium.

Enhanced radiocesium uptake by rice with fermented bark and ammonium salt amendments.

There are ongoing problems with radioactive cesium (Cs) contaminated agricultural soil after the Fukushima Daiichi Nuclear Power Plant accident. In this study, the behavior of Cs uptake by rice plants grown in soil sprayed with fermented bark amendment (FBA) was investigated. In rice cultivation by pot, the application of FBA resulted in the acceleration of Cs uptake by rice plants. This might be related to the reduction of oxidation reduction potential in the soil caused by spraying FBA. Also, when 0.1 wt% ammonium sulfate was used as a fertilizer in Cs-contaminated soil, the bioconcentration factor (BCF) of Cs taken up into rice straw was 1.4-times higher than that in soil sprayed with FBA. The Cs uptake effect was further enhanced by the combination of 1 wt% FBA with 0.1 wt% ammonium sulfate to soil where the BCF was enhanced to 1.8-times higher than that in soil sprayed with FBA alone. The enhanced uptake into rice was likely because of accelerated uptake of leachable forms of Cs based on the cation-exchange to NH4+ in soil; this was confirmed by the Cs fractionation by sequential extraction procedures. The phytoremediation capability of rice is considered to be lower than that of commonly used phytoremediation plants, but supplementation with FBA and ammonium salt could enhance Cs accumulation even for low-efficiency phytoremediation plants.

Evaluation of Photocatalytic Abilities by Variation of Conductivity and Dimethyl Sulfoxide: Photocatalytically Active TiO2-coated Wire Mesh Prepared via a Double-layer Coating Method.

Herein, we evaluated the quality of a double-layer coating method to stably immobilize photocatalysts by photodecomposition of dimethyl sulfoxide (DMSO) on a stainless-steel wire mesh using a flow analytical system, which included the reactor and conductimetric detector (FAS-CD). The prepared photocatalyst consisted of an amorphous titanium peroxide sol layer and a layer of a sol mixture containing TiO2 and amorphous titanium peroxide. Stable photocatalytic activity was demonstrated through successive photodecomposition tests of DMSO using FAS-CD/equipment.

Monitoring of the Palladium Concentration in River Water and Sediment at an Acidic Hot Spring Spa Area in Gunma Prefecture.

In an effort to elucidate the deposition pathway of Pd in river sediments, we analyzed the amount of Pd in the river water and sediments of the Yukawa and Yazawa rivers, as well as in the sediments of the Shinaki dam-lake of the Kusatsu hot-spring area, which is located northwest in Gunma Prefecture of Japan. The crystal structures and elemental compositions of the river sediment samples differed significantly before and after neutralization. This was attributed to the lime input, which also affected the Pd abundance ratio obtained by the sequential extraction procedure. Additionally, the low leachability of Pd in the sediment suggested possible difficulties in its recovery. Considering the analysis of the Pd variation in the environments, it was concluded that the Pd content in the sediment of the Shinaki dam-lake was mainly supplied by the Yukawa river water inflowing the surrounding tributary rivers and hot-spring waters before neutralization, rather than the lime input.

Use of capillary electrophoresis with dual-opposite end injection for simultaneous analysis of small ions in saliva samples from wrestlers undergoing a weight training program.

Capillary electrophoresis-capacitively coupled contactless conductivity detection (CE-C4D), conducted using an in-house-developed polyvinyl alcohol (PVA)-coated capillary system, was applied for the simultaneous analysis of small anions and cations in saliva samples from wrestlers undergoing a weight training program. Use of the PVA capillary for CE provided good reproducible ion separation with minimization of the electroosmotic flow and suppression of protein adsorption onto the capillary wall. Four cations and eight anions were separated in 12min, using a background electrolyte of 20mM MES/20mM histidine and 18-crown-6 ether (pH 6) at 20kV. The relative standard deviations (n=5) of the migration times and peak areas were <1% and <8%, respectively. The detection limit at a signal-to-noise ratio of 3 ranged from 1.6 to 10µM. Using the optimized CE-C4D system, we investigated the correlations between the concentrations of salivary ions and cortisol, which is commonly used as a stress marker. Analysis of saliva samples from ten wrestlers, who were attempting rapid weight loss before a competition, showed the following trends: (1) all ion concentrations, except for Ca(2+), Na(+), and Cl(-), increased between the first and last days of weight loss; (2) Mg(2+) increased to 166% (from 0.50mM to 1.4mM) between the first and last days of weight loss, being the highest increase of all the ions; and (3) K(+), Mg(2+), NO3(-), and SCN(-) levels were strongly correlated (P<0.05) with cortisol. The CE-C4D rapidly produced useful data on saliva ion contents, with good ion recovery as determined by the standard addition method (89-110%).

Suppression of cadmium uptake in rice using fermented bark as a soil amendment.

The contamination of rice paddies with heavy metals has become a serious concern due to their high toxicity to human health. In this study, we developed a chemical-free, fermented bark amendment (FBA) and used it for organic rice cultivation. The application of FBA resulted in the fixation of heavy metals, especially cadmium (Cd), in the soil and suppressed their uptake in brown rice. The suppression of Cd uptake was most effective, since its uptake in rice from FBA-supplemented soil was 10 times lower than that from untreated soil under ordinary water-filling conditions. These results could be explained by the rapid conversion of sulfate ions to sulfide ions, which subsequently react with Cd producing insoluble sulfide species, as well as Cd adsorption to the decomposed bark in soil. The FBA did not affect the uptake of metals, such as calcium and iron, which are necessary for the growth of rice. Thus, the FBA may suppress Cd uptake in rice, and its effectiveness is related to application time and water regime.

Simultaneous analysis of silicon and boron dissolved in water by combination of electrodialytic salt removal and ion-exclusion chromatography with corona charged aerosol detection.

Selective separation and sensitive detection of dissolved silicon and boron (DSi and DB) in aqueous solution was achieved by combining an electrodialytic ion isolation device (EID) as a salt remover, an ion-exclusion chromatography (IEC) column, and a corona charged aerosol detector (CCAD) in sequence. DSi and DB were separated by IEC on the H(+)-form of a cation exchange resin column using pure water eluent. DSi and DB were detected after IEC separation by the CCAD with much greater sensitivity than by conductimetric detection. The five-channel EID, which consisted of anion and cation acceptors, cathode and anode isolators, and a sample channel, removed salt from the sample prior to the IEC-CCAD. DSi and DB were scarcely attracted to the anion accepter in the EID and passed almost quantitatively through the sample channel. Thus, the coupled EID-IEC-CCAD device can isolate DSi and DB from artificial seawater and hot spring water by efficiently removing high concentrations of Cl(-) and SO4(2-) (e.g., 98% and 80% at 0.10molL(-1) each, respectively). The detection limits at a signal-to-noise ratio of 3 were 0.52µmolL(-1) for DSi and 7.1µmolL(-1) for DB. The relative standard deviations (RSD, n=5) of peak areas were 0.12% for DSi and 4.3% for DB.

Dynamic leaching and fractionation of trace elements from environmental solids exploiting a novel circulating-flow platform.

A dynamic flow-through microcolumn extraction system based on extractant re-circulation is herein proposed as a novel analytical approach for simplification of bioaccessibility tests of trace elements in sediments. On-line metal leaching is undertaken in the format of all injection (AI) analysis, which is a sequel of flow injection analysis, but involving extraction under steady-state conditions. The minimum circulation times and flow rates required to determine the maximum bioaccessible pools of target metals (viz., Cu, Zn, Cd, and Pb) from lake and river sediment samples were estimated using Tessier's sequential extraction scheme and an acid single extraction test. The on-line AIA method was successfully validated by mass balance studies of CRM and real sediment samples. Tessier's test in on-line AI format demonstrated to be carried out by one third of extraction time (6h against more than 17 h by the conventional method), with better analytical precision (<9.2% against >15% by the conventional method) and significant decrease in blank readouts as compared with the manual batch counterpart.

Evaluation of the water-treatment ability of silica-doped titanium dioxide-coated glass plates using a cationic coupling reagent based on a flow analytical system.

In this study, a photocatalytic plate bound to highly dispersible silica-doped titanium dioxide (SiT) on a trimethoxysilyl-propyldiethylenetriamine (dien)-coated glass plate (dien-plate) was newly synthesized, and was evaluated by a flow analytical (FA) system, which consists of a photocatalytic reactor and a spectrophotometer, to continuously monitor the absorbance of tested chemicals. The method was not required to collect any sample solution at a constant period. The SiT-dien-plate facilitated the photodecomposition of methylene blue (MB) and indigo carmine (InC) in aqueous solutions. Notably, MB was quantitatively photo-decomposed following 18 h of UV-light irradiation, related to the electrostatic adsorption of surface-bound particles. A water-treatment ability of visible-light-responsive vanadium-modified nitrogen/silica co-doped titanium dioxide fixed on the dien-plate was also evaluated by the FA system. It clarified to decompose MB and InC under visible-light irradiation. Finally, the decomposition of a humic substance dissolved from Middle West China peaty soils by the SiT-dien-plate under UV-irradiation was assessed as applying the FA system with a photocatalytic plate.

Intracellular and in vivo oxygen sensing using phosphorescent Ir(III) complexes with a modified acetylacetonato ligand.

Small luminescent molecular probes based on the iridium(III) complex BTP, (btp)2Ir(acac) (btp = benzothienylpyridine, acac = acetylacetone) have been developed for sensing intracellular and in vivo O2. These compounds are BTPSA (containing an anionic carboxyl group), BTPNH2 (containing a cationic amino group), and BTPDM1 (containing a cationic dimethylamino group); all substituents are incorporated into the ancillary acetylacetonato ligand of BTP. Introduction of the cationic dimethylamino group resulted in an almost 20-fold increase in cellular uptake efficiency of BTPDM1 by HeLa cells compared with BTP. The phosphorescence intensity of BTPDM1 internalized in living cells provided a visual representation of the O2 gradient produced by placing a coverslip over cultured monolayer cells. The intracellular O2 levels (pO2) inside and outside the edge of the coverslip could be evaluated by measuring the phosphorescence lifetime of BTPDM1. Furthermore, intravenous administration of 25 nmol BTPDM1 to tumor-bearing mice allowed the tumor region to be visualized by BTPDM1 phosphorescence. The lifetime of BTPDM1 phosphorescence from tumor regions was much longer than that from extratumor regions, thereby demonstrating tumor hypoxia (pO2 = 6.1 mmHg for tumor and 50 mmHg for extratumor epidermal tissue). Tissue distribution studies showed that 2 h after injection of BTPDM1 into a mouse, the highest distribution was in liver and kidney, while after 24 h, BTPDM1 was excreted in the feces. These results demonstrate that BTPDM1 can be used as a small molecular probe for measuring intracellular O2 levels in both cultured cells and specific tissues and organs.

Highly selective detection of trace copper(II) using bathocuproinesulfonate by flow-injection electrospray ionization mass spectrometry.

Trace Cu(2+) was detected with high selectivity using specific complexation with bathocuproinesulfonate (BCS) through flow-injection electrospray ionization mass spectrometry (FI-ESI-MS), which separates Cu(2+) from coexisting metal ions by forming a Cu-BCS complex with a high mass number. Here, only [Cu(I)(BCS)2](3-) was obtained with a high ion count. Its calibration curve was linear from 1.0 × 10(-8) to 1.0 × 10(-5) M. This method was applied to determine the Cu-complexing capacities of humic acid solution and river water samples by adding traces of Cu(2+).

Heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel and its application to a flow analytical system using flame atomic absorption spectrometry.

This study aimed to evaluate the heavy metal adsorptivity of calcium-alginate-modified diethylenetriamine-silica gel (CaAD) and incorporate this biosorbent into a flow analytical system for heavy metal ions using flame atomic absorption spectrometry (FAAS). The biosorbent was synthesized by electrostatically coating calcium alginate onto diethylenetriamine (dien)-silica gel. Copper ion adsorption tests by a batch method showed that CaAD exhibited a higher adsorption rate compared with other biosorbents despite its low maximum adsorption capacity. Next, CaAD was packed into a 1mL microcolumn, which was connected to a flow analytical system equipped with an FAAS instrument. The flow system quantitatively adsorbed heavy metals and enriched their concentrations. This quantitative adsorption was achieved for pH 3-4 solutions containing 1.0×10(-6) M of heavy metal ions at a flow rate of 5.0 mL min(-1). Furthermore, the metal ions were successfully desorbed from CaAD at low nitric acid concentrations (0.05-0.15 M) than from the polyaminecarboxylic acid chelating resin (Chelex 100). Therefore, CaAD may be considered as a biosorbent that quickly adsorbs and easily desorbs analyte metal ions. In addition, the flow system enhanced the concentrations of heavy metals such as Cu(2+), Zn(2+), and Pb(2+) by 50-fold. This new enrichment system successfully performed the separation and determination of Cu(2+) (5.0×10(-8)M) and Zn(2+) (5.7×10(-8) M) in a river water sample and Pb(2+) (3.8×10(-9) M) in a ground water sample.