Major Chemical Forms Research Articles

Combustion related ammonia promotes PM2.5 accumulation in autumn in Tianjin, China

Ammonium (NH4+) is one of the most important inorganic components in PM2.5, and plays key roles in increasing the concentration of PM2.5. Understanding the sources and formation processes of NH4+ is an effective way to control PM2.5. In this study, daily PM2.5 samples were collected from September 01 to November 30, 2017 in Tianjin, and water-soluble ion concentrations and δ15N-NH4+ in PM2.5 were analyzed. The results showed that (NH4)2SO4 and NH4NO3 were the major chemical forms of NH4+. In particular, NH4NO3 dominated the liquid water content (ALWC) increase on haze days, leading to more NH3 partitioning into the particle phase, and this formation mechanism of NH4NO3 might be self-amplified with an increase in ALWC concentrations. The mean values of δ15N-NH4+ were 14.7 ± 5.2‰, and the estimated initial ambient δ15N-NH3 was −15.6 ± 9.3‰. The mean fractional contributions of volatilization sources, fossil fuel-related sources and biomass burning were 31.9 ± 15.8%, 45.9 ± 12.6% and 22.2 ± 18.3%, respectively, which were estimated by the stable isotope mixing model. Obviously, the NH3 related to combustion emissions (68.1 ± 15.9%) dominated the source of aerosol NH4+ during autumn in Tianjin in this study. We also found that the fractional contributions of these sources have varied during different pollution periods, and the contributions of biomass burning emissions increased to 60% on haze days in November. Our results highlight that fossil fuel related source emissions of NH3 dominate the formation of NH4NO3 in autumn, leading to the occurrence of haze in autumn in Tianjin. Nevertheless, the biomass burning emissions were non-ignorable.

Intracellular processing of vitamin B12 by MMACHC (CblC).

Vitamin B12 (cobalamin, Cbl, B12) is a water-soluble micronutrient synthesized exclusively by a group of microorganisms. Human beings are unable to make B12 and thus obtain the vitamin via intake of animal products, fermented plant-based foods or supplements. Vitamin B12 obtained from the diet comprises three major chemical forms, namely hydroxocobalamin (HOCbl), methylcobalamin (MeCbl) and adenosylcobalamin (AdoCbl). The most common form of B12 present in supplements is cyanocobalamin (CNCbl). Yet, these chemical forms cannot be utilized directly as they come, but instead, they undergo chemical processing by the MMACHC protein, also known as CblC. Processing of dietary B12 by CblC involves removal of the upper-axial ligand (beta-ligand) yielding the one-electron reduced intermediate cob(II)alamin. Newly formed cob(II)alamin undergoes trafficking and delivery to the two B12-dependent enzymes, cytosolic methionine synthase (MS) and mitochondrial methylmalonyl-CoA mutase (MUT). The catalytic cycles of MS and MUT incorporate cob(II)alamin as a precursor to regenerate the coenzyme forms MeCbl and AdoCbl, respectively. Mutations and epimutations in the MMACHC gene result in cblC disease, the most common inborn error of B12 metabolism, which manifests with combined homocystinuria and methylmalonic aciduria. Elevation of metabolites homocysteine and methylmalonic acid occurs because the lack of an active CblC blocks formation of the indispensable precursor cob(II)alamin that is necessary to activate MS and MUT. Thus, in patients with cblC disease, vitamin B12 is absorbed and present in circulation in normal to high concentrations, yet, cells are unable to make use of it. Mutations in seemingly unrelated genes that modify MMACHC gene expression also result in clinical phenotypes that resemble cblC disease. We review current knowledge on structural and functional aspects of intracellular processing of vitamin B12 by the versatile protein CblC, its partners and possible regulators.

Chromium and Zinc Speciation in Airborne Particulate Matter Collected in Ulaanbaatar, Mongolia, by X-Ray Absorption Near-edge Structure Spectroscopy

ABSTRACT This study examined the chemical speciation of atmospheric particulate matter (PM) samples collected in Ulaanbaatar, Mongolia. The health effects of atmospheric aerosol depend on the particles’ size distribution, elemental composition and chemical species as well as other factors, which vary according to the pollution sources and meteorological conditions. Employing the International Atomic Energy Agency (IAEA) supported X-ray fluorescence (XRF) beamline at Elettra Sincrotrone Trieste, Italy, we used a small incidence angle for the synchrotron emission radiation in this ultra-high-vacuum environment to analyze the fine and the coarse mode (PM2.5 and PM2.5-10, respectively) through X-ray absorption near-edge structure (XANES) spectroscopy, which was applied to the K-edges of the chromium (Cr) and zinc (Zn) in PM samples selected via energy-dispersive XRF (EDXRF) analysis for their high concentrations of these transition metals. The spectroscopic results identified trivalent chromium sulfate [Cr2(SO4)3] and chromium oxide (Cr2O3) compounds as the major chemical forms of Cr in both the coarse and the fine PM fraction. Furthermore, both fractions contained abundances of sulfate (ZnSO4) and silicate (Zn2SiO4) compounds, but only the fine mode contained Zn oxalate (ZnC2O4), whereas only the coarse mode contained Zn chloride (ZnCl2). These Cr and Zn species seemed to originate from local anthropogenic sources, e.g., combustion products or traffic-related resuspended road dust. Our findings, which are based on the first chemical speciation analysis from Ulaanbaatar, provide insight into the physiochemical characteristics of atmospheric aerosols as well as information on the potential sources of Cr and Zn species bound to fine and coarse PM.

Plant-induced insoluble Cd mobilization and Cd redistribution among different rice cultivars

Selecting rice varieties that adsorb less or more Cd from soil can be respectively applied to safety rice production and phytoremediation. Considering plant-induced Cd mobilization will contribute to the rice cultivar screening. We firstly executed a pot experiment to assess the effect of rice plants on soil Cd forms (BCR method). The results showed that the presence of rice significantly reduced residual-Cd (BCR4) concentrations, indicating the rice plant-induced insoluble Cd mobilization. Subsequent sand culture trial with four rice species (conventional and hybrid low-Cd rice, conventional and hybrid high-Cd rice) and four insoluble Cd compounds (CdS, [Cd3(PO3)2], CdCO3 and CdSe) were conducted to further discuss the interaction between insoluble Cd among different rice varieties. The results showed that rice plants do solubilize soil Cd especially insoluble Cd form due to the interaction among rhizosphere acidification, root secretion of organic matter ligand and other ligands, like phytosiderophore. High-Cd cultivar and hybrid rice cultivar had a greater ability to solubilize the insoluble Cd. Visual MINTEQ predicted that free Cd2+ (∼85.6%) were the dominant Cd speciation of mobilized Cd followed by Cd-DOM complexes (∼7.80%) and other ligand-complexes (∼6.51%) in the rhizosphere solution. Cd bound to protein and pectates and to undissolved phosphate were the major mobilized-Cd chemical forms in rice roots and shoots. In addition, the subcellular analysis suggested that half of mobilized-Cd precipitated in the cell wall of rice root and shoot and the other Cd entranced into the protoplast of rice cell. The fate of rice plant-induced insoluble Cd mobilization could be an indispensable factor in prospective phytoremediation and cleaner rice production.

Characterization and Source Analysis of Water-soluble Ions in Atmospheric Particles in Jinzhong, China

ABSTRACT Size-segregated samples (< 2.5, 2.5–5, 5–10, and 10–100 µm) and PM2.5 samples were collected to analyze the water–soluble inorganic ions (WSIs, including F–, Cl–, NO3–, SO42–, Na+, NH4+, K+, Mg2+, and Ca2+), through ion chromatography from January to October in 2017 in Jinzhong. The median concentration of the total WSIs in PM2.5 was 37 µg m–3, thereby accounting for 31% of the PM2.5, with the lowest level in spring and the highest in autumn. SO42–, NO3–, and NH4+ were the most abundant substances and were primarily on the fine particles (0–2.5 µm), whereas Ca2+, Mg2+, and F– were concentrated on the coarse particles (2.5–100 µm). The results of the correlation analysis led to the conclusions that (NH4)2SO4, NH4Cl and K2SO4 were the primary compounds on the fine particles, MgSO4 and CaSO4 were the major chemical forms of WSIs on the coarse particles, thus indicating that the formation mechanisms of these compounds were different; however, NH4NO3 and KNO3 were present in both the types of particles. The particles that were observed in Jinzhong were alkaline during the study period, and their acidity was negligible. The ratio analysis showed that the highest ratio of Cl–/K+ was found in winter in both fine and coarse particles; however, no obvious distinction has been made between Mg2+/Ca2+ during the four seasons. The NO3–/SO42– ratio in coarse particles was observed to be significantly higher than that in fine particles, particularly in summer, thus indicating that the heterogeneous reaction on particles plays a vital role in the formation of NO3– in coarse particles. The PCA analysis showed that the primary factors of WSIs, which were secondary formation, coal combustion, biomass burning, dust particles, and industrial emission. The coal combustion and biomass burning have been considered as the leading emission sources to be controlled for improving air quality in Jinzhong.

Characterization and sources of dissolved and particulate phosphorus in 10 freshwater lakes with different trophic statuses in China by solution 31P nuclear magnetic resonance spectroscopy

AbstractInformation on dissolved phosphorus (DP) and particulate phosphorus (PP) is essential to evaluate the P dynamics and control eutrophication. In this work, DP and PP in 10 freshwater lakes representing various trophic statuses were analyzed by solution 31P nuclear magnetic resonance spectroscopy. The results indicated that the predominant forms of DP and PP were orthophosphate (Ortho‐P) and monoester phosphate (Mono‐P). There was a greater concentration of Ortho‐P and Mono‐P in the water and particulate matter of medium‐eutriphic lakes than in lightly eutriphic or mesotrophic lakes. α‐Glycerophophate (2.7–32.5%), β‐glycerophosphate (1.3–23.4%), guanosine 2′Mono‐P (20.2–29.3%), inositol hexakisphosphate (IHP) (8.3–36.4%) and nicotinamide adenine dinucleotide (NAD) (17.3–35.9%) were identified as the major chemical forms of Mono‐P in water and particulate matter, which originate mainly from the degradation of labile diesters, aquatic/microbial sources and a combination of terrestrial and aquatic/microbial sources. Diester phosphate (Di‐P) was dominated by teichoic acid (0.5–14.8%) and deoxyribonucleic acid (DNA) (0.6–17.7%), which originated from aquatic/microbial sources. Moreover, correlation analysis showed that dissolved Mono‐P in water and particulate matter had a positive correlation with chlorophyll‐a (Chl‐a), which indicated their potential bioavailability for algal activity. pH was a crucial parameter to control Di‐P, pyrophosphate (Pyro‐P) and polyphosphate (Poly‐P) in water. Mono‐P/PPs showed a positive correlation with Chl‐a (R2 = 0.459), total phosphorus (TP) (R2 = 0.586) and the trophic status index (R2 = 0.588), which suggested that particulate Mono‐P can potentially contribute to lake eutrophication. Both Ortho‐P and Mono‐P were major contributors of P nutrients for algae, and therefore source control and new techniques are needed for reducing eutrophication.

Effect of inoculation with arbuscular mycorrhizal fungi and blanching on the bioaccessibility of heavy metals in water spinach (Ipomoea aquatica Forsk.)

A plant's tolerance to heavy metals (HMs) and its detoxification mechanisms are associated with the subcellular distribution of HMs and their chemical forms. In this study, water spinach (Ipomoea aquatica Forsk.) was grown in two soils contaminated with a single HM (cadmium, Cd) or combined HMs (Cd and nickel, Ni). Inoculation of arbuscular mycorrizal fungi (AMF) was conducted to increase the accumulation of phosphorus (P) in plants. One major exception was to decrease the migration and accumulation of HMs in edible parts by the formation of P-HM complexes. The effects of blanching and simulated digestion on bioaccessibility were also assessed. The experimental results showed that the water spinach species used in this study had a high capacity to accumulate HMs. AMF treatment improved water spinach growth and decreased the accumulation of Ni but not that of Cd. Soluble and inorganic Cd and Ni were the major subcellular fractions and chemical forms in water spinach; these two HMs also exhibited higher migration capacities in comparison to chromium (Cr). Relative to raw tissues, 45–84% of Cd, Cr, and Ni were leached after blanching. Approximately 32–55%, 16–50%, and 27–40% of Cd, Cr, and Ni, respectively, were bioaccessible and could be metabolized by in vitro digestive fluids.

Earth Without Life: A Systems Model of a Global Abiotic Nitrogen Cycle.

Nitrogen is the major component of Earth's atmosphere and plays important roles in biochemistry. Biological systems have evolved a variety of mechanisms for fixing and recycling environmental nitrogen sources, which links them tightly with terrestrial nitrogen reservoirs. However, prior to the emergence of biology, all nitrogen cycling was abiological, and this cycling may have set the stage for the origin of life. It is of interest to understand how nitrogen cycling would proceed on terrestrial planets with comparable geodynamic activity to Earth, but on which life does not arise. We constructed a kinetic mass-flux model of nitrogen cycling in its various major chemical forms (e.g., N2, reduced (NHx) and oxidized (NOx) species) between major planetary reservoirs (the atmosphere, oceans, crust, and mantle) and included inputs from space. The total amount of nitrogen species that can be accommodated in each reservoir, and the ways in which fluxes and reservoir sizes may have changed over time in the absence of biology, are explored. Given a partition of volcanism between arc and hotspot types similar to the modern ones, our global nitrogen cycling model predicts a significant increase in oceanic nitrogen content over time, mostly as NHx, while atmospheric N2 content could be lower than today. The transport timescales between reservoirs are fast compared to the evolution of the environment; thus atmospheric composition is tightly linked to surface and interior processes.

Study on the simultaneous reduction of methylmercury by SnCl2 when analyzing inorganic Hg in aqueous samples

Mercury (Hg) is among the most concerned contaminants in the world. It has three major chemical forms in the environment, including Hg0, Hg2+, and methylmercury (MeHg). Due to their differences in toxicity, mobility, and bioavailability, speciation analysis is critical for understanding Hg cycling and fate in the environment. SnCl2 reduction-atomic fluorescence spectrometry detection is the most commonly used method for analyzing inorganic Hg. However, it should be noted that MeHg may also be reduced by SnCl2, which would result in the overestimation of inorganic Hg. In this study, the reduction of MeHg by SnCl2 in both de-ionized (DI) water and four natural waters was investigated. The results showed that MeHg could be reduced by SnCl2 in DI water whereas this reaction was hard to occur in tested natural waters. By investigating the effects of water chemical characteristics (dissolved organic matter, pH and common anions and cations) on this reaction, SO42− was identified to be the dominant factor prohibiting SnCl2 induced MeHg reduction in natural waters. SO42− in natural waters was evidenced to be reduced to S2− by SnCl2 and the generated S2− can complex with MeHg to form MeHgS− which is hard to be reduced by SnCl2. Findings of this study indicate that the effect of MeHg reduction by SnCl2 on inorganic Hg analysis is negligible in natural waters; however, at simulated experimental systems without SO42−, SO42− should be added as protecting agents to prevent MeHg reduction when analyzing inorganic Hg if it would not cause any other unwanted effects.

Comparison of Foliar and Root Application of Potassium Dihydrogen Phosphate in Regulating Cadmium Translocation and Accumulation in Tall Fescue (Festuca arundinacea)

The efficiency of phytoremediation is mainly dependent on the capacity of plants in absorption, translocation, and accumulation of Cd. This study was designed to investigate whether Cd translocation and accumulation in tall fescue plants was regulated by foliar application of KH2PO4. The results showed that the foliar application of KH2PO4 significantly increased Cd concentration and total Cd accumulated in leaves and the capacity of Cd extraction, compared to the root application. The water-soluble organic acid complexes and the pectate- and protein-integrated Cd were the two major Cd chemical forms deposited in leaves. The foliar application increased Cd in the pectate- and protein-integrated forms and decreased the water-soluble forms in leaves. Cd phosphates were not the major chemical forms deposited in leaves in both foliar and root applications. The results indicated that the foliar application of KH2PO4 enhanced Cd accumulation in leaves of tall fescue, which might be associated with the leaf deposit of the pectate- and protein-integrated Cd forms.

Speciation of phosphorus in the continental shelf sediments in the Eastern Arabian Sea

The distributions of various forms of phosphorus (P) and their relation with sediment geochemistry in two core sediments near Karwar and Mangalore offshore have been studied through the modified SEDEX procedure (Ruttenberg et al., 2009) and bulk chemical analysis. The present study provides the first quantitative analysis of complete phosphorus speciation in the core sediments of the Eastern Arabian shelf. The chemical index of alteration (CIA), chemical Index of Weathering (CIW) and Al–Ti–Zr ternary diagram suggest low to moderate source area weathering of granodioritic to tonalitic source rock composition, despite the intense orographic rainfall in the source area. Due to the presence of same source rock and identical oxic depositional environment, the studied sediments show the same range of variation of total phosphorus (24 to 83µmol/g) with a down-depth depleting trend. Organic bound P and detrital P are the two major chemical forms followed by iron-bound P, exchangeable/loosely bound P and authigenic P. The authigenic P content in the sediments near Mangalore coast varies linearly with calcium (r=0.88) unlike that of Karwar coast. The different reactive-phosphorus pools exhibit identical depleting trend with depth. This indicates that the phosphorus released from the organic matter and Fe bound fractions are prevented from precipitating as authigenic phosphates in the deeper parts of the sediment column. The low concentration of total P, dominance of detrital non-reactive fraction of P and inhibition of formation of authigenic phosphate result in the absence of active phosphatization in the Eastern Arabian Shelf in the studied region. High sedimentation rate (35–58cm/kyr) and absence of winnowing effect appear to be the dominant factor controlling the P-speciation in the studied sediments.

Importance of reduced sulfur for the equilibrium chemistry and kinetics of Fe(II), Co(II) and Ni(II) supplemented to semi-continuous stirred tank biogas reactors fed with stillage

The objective of the present study was to assess major chemical reactions and chemical forms contributing to solubility and speciation of Fe(II), Co(II), and Ni(II) during anaerobic digestion of sulfur (S)-rich stillage in semi-continuous stirred tank biogas reactors (SCSTR). These metals are essential supplements for efficient and stable performance of stillage-fed SCSTR. In particular, the influence of reduced inorganic and organic S species on kinetics and thermodynamics of the metals and their partitioning between aqueous and solid phases were investigated. Solid phase S speciation was determined by use of S K-edge X-ray absorption near-edge spectroscopy. Results demonstrated that the solubility and speciation of supplemented Fe were controlled by precipitation of FeS(s) and formation of the aqueous complexes of Fe-sulfide and Fe-thiol. The relatively high solubility of Co (∼20% of total Co content) was attributed to the formation of compounds other than Co-sulfide and Co-thiol, presumably of microbial origin. Nickel had lower solubility than Co and its speciation was regulated by interactions with FeS(s) (e.g. co-precipitation, adsorption, and ion substitution) in addition to precipitation/dissolution of discrete NiS(s) phase and formation of aqueous Ni-sulfide complexes.

Characterization and Risk Assessment of Exposure to Volatile Organic Compounds in Apartment Buildings in Harbin, China

This study analyzed the risk of exposure to volatile organic compounds (VOCs) in the apartment buildings (including bedrooms, living rooms, kitchens and study rooms) in Harbin, China. The concentration of total VOCs in bedrooms showed the lowest value with an average of 482.6 mg/m(3). 32.33 % of total measured VOCs correspond to aromatic hydrocarbons. The major chemical forms of the identified VOCs in other 3 types of rooms were alcohols which contributed to 30.66 % (in living rooms), 36.55 % (in kitchens) and 35.43 % (in study rooms) separately. Formaldehyde was the pollutant of highest concern given its high chronic toxic and carcinogenic risk levels according to the health assessment. Other pollutants of concern for human heal risks were benzene and naphthalene. The non-cancer risk by the exposure to naphthalene ranged from 2.39 to 2.80 in 4 target groups, which is more than 1.0 considered as a hazarded level to human health.

Characteristics of phosphorus species identified by 31P NMR in different trophic lake sediments from the Eastern Plain, China

Because phosphorus (P) is a vital biogenic element for aquatic ecosystems, a deeper understanding for the turnover of P in lake sediments is much needed. In this study, seven lakes representing major lake types in the Eastern Plain region of China were selected so to identify and quantify the characteristics and lability of sediment P. A relatively new approach called Phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMR) was adopted to detect the different P species in the lake sediments. The experimental results indicate that NaOH–EDTA extraction by 31P NMR analysis is a useful technique for determining and measuring each P compound in the studied shallow lake sediments. Orthophosphate, orthophosphate monoesters and orthophosphate diester are identified as the major chemical forms of phosphorus in the sediments. There is a greater content of these compounds in the sediments of the highly polluted lakes than the less-polluted lakes. Moreover, the content of orthophosphate, orthophosphate monoesters and orthophosphate diester (sediment) is in proportion to the total P and Chla (chlorophyll a) (overlying water) in the lakes of the Eastern Plain, indicating their potential bioavailability. This positive correlation also implies that the role organic P plays in lake eutrophication should be given more attention, particularly for the heavily polluted sediments. Finally, a significant correlation exists between APA and TP and IP in the Eastern Plain lake region. A possible hydrolytic pathway for the various organic phosphorus compounds by APA is also discussed.

The dinucleotide CG as a genomic signalling module

The DNA sequence 5’CG (CpG) is self-complementary and can exist in three major chemical forms depending on the modification status of its cytosine moiety. To understand the functional significance of the CpG dinucleotide, we study proteins that bind either its methylated or unmethylated form. These proteins are likely mediators of CpG signalling that influence chromatin modification and thereby genome activity. The local density of CpG varies dramatically within genomic DNA. In the bulk genome CpG is rare and highly methylated, but in so-called “CpG islands” (CGIs) it is dense and usually non-methylated. A signature histone mark at non-methylated CGIs and also at transcriptionally active genes is trimethylation of histone H3 lysine 4. We are exploring the mechanisms by which DNA sequence features that are shared by all CGIs influence this and other epigenetic marks. In contrast, proteins that interact with methyl-CpG are thought to promote gene silencing by recruiting transcriptional corepressors. In particular mutations in the gene for the methyl-CpG binding protein MeCP2 cause the autism spectrum disorder Rett Syndrome. By studying MeCP2 we are learning about its partner proteins that mediate effects on chromatin. These findings allow us to evaluate competing models for MeCP2 function and they illuminate the biology of DNA methylation and the molecular basis of this neurological condition.

The dinucleotide CG as a genomic signalling module

The DNA sequence 5’CG (CpG) is self-complementary and can exist in three major chemical forms depending on the modification status of its cytosine moiety. To understand the functional significance of the CpG dinucleotide, we study proteins that bind either its methylated or unmethylated form. These proteins are likely mediators of CpG signalling that influence chromatin modification and thereby genome activity. The local density of CpG varies dramatically within genomic DNA. In the bulk genome CpG is rare and highly methylated, but in so-called “CpG islands” (CGIs) it is dense and usually non-methylated. A signature histone mark at non-methylated CGIs and also at transcriptionally active genes is trimethylation of histone H3 lysine 4. We are exploring the mechanisms by which DNA sequence features that are shared by all CGIs influence this and other epigenetic marks. In contrast, proteins that interact with methyl-CpG are thought to promote gene silencing by recruiting transcriptional corepressors. In particular mutations in the gene for the methyl-CpG binding protein MeCP2 cause the autism spectrum disorder Rett Syndrome. By studying MeCP2 we are learning about its partner proteins that mediate effects on chromatin. These findings allow us to evaluate competing models for MeCP2 function and they illuminate the biology of DNA methylation and the molecular basis of this neurological condition.

Chemical Forms of Arsenic and Selenium Leached from Mudstones

Batch leaching experiments were conducted to elucidate the leaching behaviors and chemical forms of arsenic (As) and selenium (Se) from excavated mudstones. The results showed that As and Se concentrations in the leachate were higher than the environmental standards (10μg/L), and that the major chemical forms of As and Se were arsenate (As(V)) and selenate (Se(VI)), respectively. Consecutivebatch leaching experiments showed that the major chemical form of As was As(V) regardless of the number of extraction whereas that of Se changed from Se(VI) to selenite (Se(IV)) with the number of extraction. These results agreed with the calculated results by geochemical modeling. Understanding the major chemical species of hazardous elements leached from mudstones is valuable in the mitigation of these potential sources of contamination.

The mPlrp2 and mClps genes are involved in the hydrolysis of retinyl esters in the mouse liver

Retinyl esters are the major chemical forms of vitamin A stored in the liver, and can be delivered to peripheral tissues for conversion into biologically active forms. The function and regulation of the hepatic genes that are potentially involved in catalyzing the hydrolysis of retinyl esters remain unclear. Here we show that two lipid hydrolytic genes, pancreatic-related protein 2 (mPlrp2) and procolipase (mClps), expressed specifically in the mouse pancreas, are associated with the ratio of S-adenosylmethionine (AdoMet) to S-adenosylhomocysteine (AdoHcy). Light illumination deficiency or administration of 5'-AMP elevated the ratio of AdoMet to AdoHcy and induced the expression in the liver of mPlrp2 and mClps, which was blocked by all-trans retinoic acid. Mice fed a vitamin A-free diet exhibited increased activation of hepatic mPlrp2 and mClps expression, which was associated with increased methylation of histone H3K4 residues located near the mPlrp2 and mClps promoters. Inhibition of hepatic mPlrp2 and mClps expression by a methylase inhibitor, methylthioadenosine, markedly decreased plasma retinol levels in these mice. The activated hepatic stellate cell (HSC)-T6 cell line specifically expressed mClps and mPlrp2. Inhibition of mClps gene expressions by short hairpin RNA (shRNA) decreased hydrolysis of retinyl esters in the HSC-T6 cell line. These data suggest that the conditional expression of mPlrp2 and mClps is involved in the hydrolysis of retinyl esters in the mouse liver.

Iodide sorption and partitioning in solid, liquid and gas phases in soil samples collected from Japanese paddy fields

Sorption kinetics of iodide (I(-)), which is one of the major inorganic chemical forms of iodine in soil environments, were studied under four sets of experimental conditions characterised by temperature or biological activity. We compared partitioning ratios in solid, liquid and gas phases in soils as well as soil-soil solution distribution coefficients (K(d)s) at two different temperatures 4 and 23 °C, for 63 paddy soil samples collected throughout Japan. Interestingly, (125)I emission from soil was observed; the partitioning ratios in gas phase ranged from 0 to 27 % at 4 °C and from 0 to 42 % at 23 °C. In addition, the authors found that K(d) values at 23 °C had good correlation with pH though there was no correlation between K(d) values at 4 °C and pH because of the difference in biological activity.

Synthesis of B6 vitamin

The importance of vitamin B6 has been known since its discovery in the 1940's. Chemical tests, elestrometric titration determinations, and absorption spectrum studies showed that this vitamin exists in three major chemical forms: pyridoxine (an alcohol), pyridoxal (an aldehyde), and pyridoxamine (a primary amine). Vitamin B6 is needed for more than 100 enzymes involved in protein metabolism, and it is assumed that this vitamin is cofactor of metabolic processes more important than any other substance. A deficiency of vitamin B6 in the human diet leads to severe disorders. Vitamin B6 is necessary for the proper function of the immune and nervous system, and helps the body convert protein to energy. This paper describes the history, properties and applications of vitamin B6, elucidation of chemical structure, and different procedures for synthesis of pyridoxine and pyridoxamine.