Ba Uptake Research Articles

Foliar application of Fe-fulvic acid: A strategy to reduce heavy metal accumulation and enhance nutritional quality

Pepper is a key agricultural crop susceptible to accumulating heavy metals like cadmium (Cd) and barium (Ba), posing significant health risks. To address these issues, this study investigated the effects of foliar applications of fulvic acid (FA), Zn-fulvic acid (Zn-FA), and Fe-fulvic acid (Fe-FA) on Ba and Cd uptake in pepper tissues, as well as their impact on nutritional quality, biomass, and leaf enzyme activity. Results indicated that Fe-FA application significantly reduced Cd and Ba in pepper fruit by 25 % and 93 %, respectively. Additionally, Fe-FA enhanced pepper growth, increasing vitamin C and phenolic compounds by 136 % and 13 %, respectively. Metabolomics analysis revealed that Fe-FA application up-regulated 857 metabolites and down-regulated 1045 metabolites. Furthermore, Fe-FA primarily influenced amino acid, carbohydrate, and lipid metabolism, promoting pepper growth. These findings suggest that Fe-FA foliar application offers a promising strategy for reducing Ba and Cd accumulation in pepper fruits while enhancing its nutritional quality.

Molecular mechanism of homologous lactic acid bacteria regulating liver cell injury of snakehead fish

In order to clarify the molecular mechanism of the homologous LAB regulating the liver cell injury of C. argus, this study used Fxr as the key target protein for the treatment of liver cell injury, used LCA to construct the liver cell injury model, and used the Fxr inhibitor GS to specifically block Fxr and its related signaling pathways will further explore the protective mechanism of homologous L. lactis L19 against liver injury in C. argus in vitro. The results showed that the LCA-induced liver cell injury model of C. argus was successfully constructed. The optimal concentration of LCA was 20 μM, and the optimal duration of action was 24 h. 1.0 × 108 CFU/mL L. lactis L19 ECP showed a protective effect on LCA-induced liver cell injury, remarkably decrease the levels of liver injury-related biochemical parameters AST, ALT, ALP and LDH (P < 0.05), and regulate the expressions of BA metabolism-related genes fxr, bsep, mrp2, shp, cyp7a1 and cyp8b1 and BA metabolism-related proteins Fxr, Bsep, Shp and Cyp7a1. It is revealed that L. lactis L19 is a possible molecular mechanism that regulates the liver cell injury of C. argus by activating Fxr and its related signal pathways. In vitro test results show that L. lactis L19 can enhance the proliferation of hepatocytes, promote the efflux and metabolism of toxic BA, inhibit the BA synthesis and uptake, and play a protective role in LCA-induced liver cell injury in C. argus. At the gene and protein levels, it was verified that L. lactis L19 can activate Fxr and its related signal pathways, and proved that the protective effects of L. lactis L19 on LCA-induced liver cell injury was blocked by GS. Thus, L. lactis L19, as a recognized probiotic, has a bright future in the treatment of liver injury-related diseases.

Growth responses of genetically diverse rice (&lt;em&gt;Oryza sativa&lt;/em&gt; L.) cultivars to Arsenic stress

Although arsenic (As) is a toxic element for plant growth, it can accumulate in rice plants to higher levels. A case-control experiment was carried out to investigate the impact of As in soil on rice plant growth. Nine (9) different native and improved rice cultivars were grown in soils with 10 mg/kg As. Total As content in grains was quantified using an ICP-MS. The mean As content in control samples was 15.8 µg/kg while As treatment samples showed 122 µg/kg. Grains of improved rice variety of Bg 300 showed the highest As accumulation. The chlorophyll content declined by 28% under As stress and 56% tiller losses were also observed. The significant reduction of plant growth has given an impaired grain yield under As-treated conditions. Soil arsenic also showed a significant impact on Ni, Rb, and Ba uptake and accumulation. This study showed that As accumulation in rice is cultivar-dependent and also indicated a drastic reduction of the yield under elevated As levels. The native cultivar, Kahawanu was shown the lowest As-accumulation (90.1 mg/kg) under elevated As within the nine rice cultivars. So it can be identified as the best resistance cultivar for the As stress. The results can be utilized for developing high-tolerance rice varieties using new breeding technologies.

Barium and strontium isotope fractionation by cyanobacteria forming intracellular carbonates

While barium (Ba) and strontium (Sr) stable isotopes are increasingly used as tracers of biogeochemical processes and paleo-proxies, the role of biotic processes on Ba and Sr isotope fractionation is poorly understood. Here, Ba and Sr stable isotope fractionations were studied in the laboratory using Gloeomargarita lithophora, a cyanobacterium that selectively hyperaccumulates Ba and Sr within intracellular amorphous carbonate biominerals. Our results show that lighter Ba and Sr isotopes are enriched in G. lithophora cells compared to the initial solution by –0.24‰ to –0.03‰ (δ137Ba) and –0.33‰ to –0.01‰ (δ88Sr) depending on the stage of the experiment. The fractionation of Ba and Sr isotopes is distinct in magnitude from that occurring during abiogenic and other known biogenic carbonate formation cases. Additionally, using a Rayleigh fractionation model, the fractionation factors of Ba and Sr isotopes between G. lithophora cells and the fluid (the growth medium), i.e., Δ137Ba(bac-sol) and Δ88Sr(bac-sol), were equal to –0.25‰ and between –0.46‰ and –0.38‰, respectively. Interestingly, δ137Basol and δ88Srsol decreased at the end of Ba and Sr uptake stages back towards their initial values, which caused departures from the Rayleigh fractionation model. This suggests the existence of a back reaction resulting in a Ba and Sr outflux from cells to the solution. Possible hypotheses for this back-reaction include dissolution of amorphous carbonate inclusions in response to cellular stress, or a first-order rate dependence of amorphous carbonate dissolution on the amount of Ba and Sr inside the cell. Our findings suggest that bacteria forming intracellular amorphous carbonates could introduce Ba and Sr isotope variability in environmental records, especially in environments where they thrive. Moreover, the enrichment of lighter isotopes of Ba and Sr during amorphous carbonate formation is consistent with that occurring during the formation of other biogenic carbonates but slightly differs in magnitude, opening a discussion about the possibility to use Δ137Ba(bac-sol) and Δ88Sr(bac-sol) as an indicator of intracellular amorphous carbonate biomineralization in the fossil rock record. Overall, this work highlights the complexity of the biological uptake of alkali-earth metals and stresses the overlooked role of bacteria forming intracellular amorphous carbonates in Ba and Sr biogeochemical cycles.

Dietary supplementation with garcinol during late gestation alleviates disorders of bile acid metabolism and improves the performance of sows and newborn piglets.

The present study was conducted to evaluate the effects of dietary garcinol supplementation during late gestation on bile acid metabolism and performance of sows. Sixty sows (Duroc × Yorkshire × Landrace; second- or third-parity; n = 20) with disorder of bile acid metabolism were randomly divided into three groups: control diet (CON; basal diet), basal diet with 200 mg garcinol (Low Gar), and basal diet with 600 mg garcinol (High Gar) per kg of feed. The body weight (BW); backfat thickness and litter size of the sows; and birth weight, weaning weight, and mortality of piglets were recorded. Sows' blood was collected for the measurements of hematological parameters and antioxidative and immune indexes, and indicators related to bile acid metabolism, respectively. The colostrum and fecal samples of the sows were also collected for analysis of colostrum composition and apparent total tract nutrient digestibility. Garcinol had no effect on the BW and backfat thickness of the sows but significantly decreased the mortality and number of weak litter (P < 0.05). Moreover, the white blood cell counts, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activity in the plasma of the sows were increased more significantly (P < 0.05) in the garcinol groups than that in the CON group, whereas the malondialdehyde (MDA) content was decreased (P < 0.05). Dietary supplementation with garcinol significantly reduced TBA concentrations (P < 0.05). The content of immunoglobulin A (IgA) and immunoglobulin G (IgG) in the plasma and in colostrum of sows were increased more significantly (P < 0.05) in the garcinol groups than that in the CON group. In addition, dry matter (DM), Ash, and EE in the colostrum were similar between groups (P > 0.05), whereas the garcinol significantly increased the crude protein (CP) in the colostrum. The apparent total tract nutrient digestibility was similar between treatments. Garcinol treatment induced a gradually decreased (P > 0.05) the expression of genes involved in BA synthesis (CYP7A1, CYP8B1), BA uptake (NTCP, OATP1A2), BA secretion (BSEP and MRP2), BA detoxification (SULT2A1), and BA efflux into the blood circulation (OSTβ). Collectively, this study indicates that sows fed with garcinol in late gestation showed relieved bile acid metabolism disorder and improved sows performance, antioxidative status, colostrum protein content, showing promise in natural plant extract nutrition for sows with disorder of bile acid metabolism.

Organic Anion Transporting Polypeptide (OATP) 1B3 is a Significant Transporter for Hepatic Uptake of Conjugated Bile Acids in Humans

OATP1B3/SLCO1B3 is a human liver-specific transporter for the clearance of endogenous compounds (eg, bile acid [BA]) and xenobiotics. The functional role of OATP1B3 in humans has not been characterized, as SLCO1B3 is poorly conserved among species without mouse orthologs. Slc10a1-knockout (Slc10a1-/-), Slc10a1hSLCO1B3 (endogenous mouse Slc10a1 promoter-driven human-SLCO1B3 expression in Slc10a1-/- mice), and human SLCO1B3 liver-specific transgenic (hSLCO1B3-LTG) mice were generated and challenged with 0.1% ursodeoxycholic-acid (UDCA), 1% cholic-acid (CA) diet, or bile duct ligation (BDL) for functional studies. Primary hepatocytes and hepatoma-PLC/RPF/5 cells were used for mechanistic studies. Serum BA levels in Slc10a1-/- mice were substantially increased with or without 0.1% UDCA feeding compared with wild-type (WT) mice. This increase was attenuated in Slc10a1hSLCO1B3-mice, indicating that OATP1B3 functions as a significant hepatic BA uptake transporter. Invitro assay using primary hepatocytes from WT, Slc10a1-/-, and Slc10a1hSLCO1B3-mice indicated that OATP1B3 has a similar capacity in taking up taurocholate/TCA as Ntcp. Furthermore, TCA-induced bile flow was significantly impaired in Slc10a1-/- mice but partially recovered in Slc10a1hSLC01B3-mice, indicating that OATP1B3 can partially compensate the NTCP function invivo. Liver-specific overexpression of OATP1B3 markedly increased the level of hepatic conjugated BA and cholestatic liver injury in 1% CA-fed and BDL mice. Mechanistic studies revealed that conjugated BAs stimulated Ccl2 and Cxcl2 in hepatocytes to increase hepatic neutrophil infiltration and proinflammatory cytokine production (eg, IL-6), which activated STAT3 to repress OATP1B3 expression by binding to its promoter. Human OATP1B3 is a significant BA uptake transporter and can partially compensate Ntcp for conjugated BA uptake in mice. Its downregulation in cholestasis is an adaptive protective response.

Intercalated organo-bentonite as efficient biosorbent for aromatic carboxylic acids from wastewater

This study aims to prepare intercalated organo-bentonite using cetylbenzyldimethylammoniumbromide (CBDAB) and investigate its ability for the removal of benzoic (BA) and salicylic (SA) acids from wastewater. The obtained results confirm the intercalation of CBDA into the bentonite interlayer. Several important parameters of SA and BA adsorption onto sodium bentonite (Na-bent) and intercalated bentonite (CBDA-bent) including the adsorbent dosage, contact time, pH, ionic strength, and temperature are investigated in batch mode. Overall, CBDA-bent, which possesses a high specific surface (32 m2/g) area and a pore volume (0.14 cm3/g) demonstrates promising prospects for SA and BA adsorption, reaching 55.2 mg/g and 64.5 mg/g, respectively. The SA and BA are found to primarily interact well through both surface and interlayer processes in basic media. The equilibrium experimental data have been analyzed by Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherms; nonetheless the adsorption is well described by the Langmuir model. The influence of contact time on SA and BA uptake is modeled using pseudo second-order, pseudo first-order, intraparticle diffusion, and Boyd kinetic models. An intraparticle diffusion mechanism is found to control the adsorption process, where the internal mass transfer is higher than the external mass transfer. A thermodynamic study shows that the adsorption of both acids is not spontaneous and endothermic. Desorption of SA and BA acids from both Na-bent and CBDA-bent has been performed and the possibilities for reuse investigated.

Novel hybrid multifunctional composite of chitosan and altered basalt for barium adsorption: Experimental and theoretical studies

Herein, the starting low‒cost and eco‒friendly weathered basalt (WB) was found to be rich in zeolite and clay minerals, which have wide applications in water purification. WB was chemically activated by hydrogen peroxide (H2O2) followed by the interaction with chitosan (Ch) to fabricate a new hybrid composite (WB/Ch) with multifunctional groups. The resulted WB/Ch composite was characterized by XRD, FTIR, SEM, and applied for Ba (II) adsorption at pH 5.0 and different temperatures (i.e., 25, 35 and 45 °C). The adsorption data were fitted to kinetics, classical (Langmuir, Freundlich and Dubinin–Radushkevich) as well as advanced statistical (multilayer) models. The adsorption data of Ba(II) onto WB/Ch were described well by the pseudo-second-order and the applied traditional equilibrium models. The monolayer adsorption capacity (qmax = 45.78 mg g−1) reflected the high removal efficiency of WB/Ch for Ba(II) uptake as compared to varied natural and synthetic adsorbents. Steric and energetic parameters of the multilayer model were interpreted to understand the interaction mechanism between the Ba(II) ions and WB/Ch active sites. Theoretical number of receptor sites (n) was less than unity at all temperatures revealing multi–docking adsorption mechanisms. Interaction between Ba(II) and WB/Ch of the first layer played the principle role in increasing the adsorption capacities (Qsat) from 115.06–128.86 mg g‒1 within the temperature range of 25–45 °C. The total adsorbed Ba(II) layers (the Nt parameter) decreased from 2.79 to 2.02 with temperature thus reflecting its insignificant role to determine the Qsat values. The calculated adsorption energies varied from 22.35 to 28.56 kJ mol‒1 indicated that the Ba(II) adsorption onto the WB/Ch composite was endothermic and related to physical forces. Thermodynamic parameters including Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) reflected the endothermic and spontaneous nature of Ba(II) adsorption process.

Hyperglycemia exacerbates dyslipidemia-induced changes in uptake, synthesis, and transporters of bile acids in rats: Assessment of restorative potentials of ALA and EPA + DHA

In this study, under dyslipidemia (D) and dyslipidemia with diabetes (DD) conditions, we assessed the intestinal bile acid (BA) uptake, BA transporter expression and de novo BA synthesis in rats. The restorative potentials n-3 fatty acids [{α-linolenic acid (ALA), DD+canola oil (CNO)} and eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA), DD+fish oil (FO)}] were also assessed. DD group had significantly (p < 0.05) increased intestinal BA uptake and Asbt and Osta/b mRNA expression, increased serum BA level, decreased hepatic Ntcp, Bsep and Cyp7a1 mRNA expression, increased hepatic HMG-CoA reductase activity, increased hepatic Fxr and Shp mRNA expression, decreased hepatic Lrh-1 and Hnf4a mRNA expression and decreased fecal BA level, when compared to control, D, DD+CNO, and DD+FO group. Our data show for the first time that, hyperglycemia exacerbates dyslipidemia-induced dysregulation of BA metabolism and transport. Dietary EPA+DHA exhibited superior effect than ALA in normalizing dyslipidemia and hyperglycemia-induced disturbances.

Comparison between cesium and sodium retention on calcium silicate hydrate (C[sbnd]S[sbnd]H) phases

Batch sorption experiments and sorption modelling were combined to analyse the mechanisms of Cs and Na retention on calcium silicate hydrate phases, CSH, and to identify similitudes/differences between the two elements.The role played by the CSH's Ca/Si ratio and the tracer concentration on alkali ions retention was experimentally analysed. For both elements, sorption decreased when the Ca/Si ratio increased, but only in the case of Cs sorption was clearly not linear.Distribution coefficients (Kd) for Cs were higher than those of Na at trace concentration and low Ca/Si ratio but at high alkali concentrations, Kd values for Cs and Na were always comparable. This was a first indication that low-density but high selective sorption sites exist on the CSH surface, accessible for Cs and not for Na.Electrophoretic measurements were carried out to evaluate the variation of the CSH surface charge (ζ-potential) upon alkali addition and to support modelling studies. Under similar experimental conditions, the change produced by Cs or Na additions on the ζ-potential of the gels was always similar.Different sorption models were proposed to fit the experimental data, based on the adsorption data, on the variation of CSH surface potential upon Cs/Na sorption and on previous tests showing the competitive effects of Na and Cs on Ba uptake. Their adequacy will be discussed as well as the differences/similitudes of sorption behaviour for both elements.

Impact of the cyanobacterium Gloeomargarita lithophora on the geochemical cycles of Sr and Ba

The cyanobacterium Gloeomargarita lithophora forms intracellular amorphous calcium carbonates and has been recently shown to accumulate Ca, Sr and Ba at a high level with a preference for Ba > Sr > Ca. This is of interest to the design of bioremediation strategies for Sr and/or Ba pollutions in aquatic systems. However, this preference has so far been evidenced at high dissolved Sr and Ba concentrations only, i.e. conditions rarely encountered in the environment. Here, we followed the uptake of alkaline earth metals (Mg, Ca, Sr and Ba) by G. lithophora in alkaline solutions with more environmentally-relevant, low Sr and Ba concentrations. Two settings were analyzed: 1) batch cultures in which alkaline earth metals were added only at the beginning; 2) cultures supplemented continuously with fragments of alkaline earth element-containing carbonate microbialites. The growth of G. lithophora was higher in the presence of microbialites, suggesting that some limiting elements, possibly P and/or Ca, were supplied by their dissolution. In the two settings, the concentration of dissolved Ca was in the micromolar range, while it was more than three orders of magnitude lower for Ba and Sr. In cultures with microbialite fragments, these low Sr and Ba concentrations resulted from an input by aragonite dissolution balanced by high Sr and Ba uptake by the cyanobacterial cells with high affinity. Thereby, the continuous supply of alkaline earth metals by microbialite dissolution increased the Sr and Ba content of the cyanobacterial intracellular carbonates over time. G. lithophora incorporated preferentially Ba and Sr over Ca even at very low Ba and Sr concentrations and despite the presence of Ca at a much higher concentration. Overall, this shows the capability of G. lithophora to impact the geochemical cycles of Sr and Ba by buffering dissolved Sr/Ca and Ba/Ca ratios at low levels.

Analysis of barium retention mechanisms on calcium silicate hydrate phases

Calcium silicate hydrate (C-S-H) phases mostly contribute to contaminant retention in cement. The adsorption mechanisms of Ba on C-S-H phases with four different Ca/Si ratios were investigated by batch sorption experiments. The sorption kinetics, the effects of the solid to liquid ratio and the presence of alkalis in solution were analysed. Sorption isotherms in a wide range of Ba concentrations (from 10−10 to 1·10−1M) were performed.To understand the underlying retention mechanisms, the effects of Ba adsorption on surface potentials were additionally examined. The main objective of this study was to develop a sorption model able reproducing not only the Ba sorption behaviour, but also the C-S-H surface potential before and after Ba uptake. The reactions and model parameters selected for satisfying these conditions are discussed in the paper. A three-site model, with weak and strong silanol sites and one exchange site, which satisfactorily fulfils the initial aims, is proposed.

Geochemistry of barium in soils supplied with carbonatite rock powder and barium uptake to plants

Apatite-biotite-carbonatite (short form: carbonatite) rock powder originating from Lillebukt alkaline complex, N-Norway is a potential liming and multi-nutrient fertilizer. However, the elevated contents of potentially bio-toxic barium (Ba) (up to 5.5 g kg−1) is a matter of concern. A pot experiment was conducted in order to investigate the geochemistry of Ba in a sandy peat-containing growth media treated with carbonatite, with special focus on Ba-speciation in the pore water. These results were correlated with Ba uptake in Trifolium repens L. (white clover) and Fesctua arundinácea L. (tall fescue). The Ba-speciation and bioavailability as affected by treatment and plant growth was conducted using WHAM/Model VI version 7.0.4 and the diffusive gradients in thin films (DGT) technique, respectively. The increasing cation exchange capacity (CEC) in the growth media, and colloidal fulvic acids (FA) decreased the Ba2+ concentration in pore water. Both the Ba detected in DGT (Badgt), and exchangeable Ba (Baexc) were higher in pots containing rock powder. A strong relationship between Baexc and diffusively bound Ba to FA (Badfa) with plant uptake was evident. The latter was likely initiated by organic material mobilization of Ba from carbonatite. The mobilized Ba bound to FA (Bafa) in pore water was mainly bound diffusively, and the Badfa fraction was thus made available to plants. Finally, the Badgt was increased in pots grown with white clover compared to tall fescue. Further investigation is required to determine if this is related to increased rhizosphere activity by plants or to the nitrogen fixating plant-microbe relationship.

Can liming reduce barium uptake by agricultural plants grown on sandy soil?

AbstractUptake of barium (Ba) from soil by vascular plants varies among species. Despite the toxicity of soluble Ba compounds to plants, research on mechanisms controlling Ba uptake from natural soils is scarce. This study investigated the treatment effect of lime (CaCO3) added to a sandy soil containing a total of 500 mg Ba kg−1 on uptake and interspecies distribution of Ba in legumes and other cultivated food and feed plants. Nine species of grasses, vegetables, herbs, and legumes were cultivated under controlled conditions in a greenhouse experiment. The plants were harvested at maturity or flowering, dried, milled, and digested with nitric acid using the microwave technique prior to ICP‐MS analysis. All plant species acquired Ba from the soil in considerable amounts, probably due to low Ba adsorption potential of the sandy soil. Shoot tissue concentrations ranged from about 100 (grass) to 600 mg Ba kg−1 (legume) and root concentrations from about 100 (tuber vegetable) to 700 mg kg−1 (legume). Vicia cracca L. (bird vetch) showed an accumulation capacity due to high shoot concentrations of Ba compared to the other species. Higher yield accompanied by a potential dilution effect can partly explain why Trifolium repens L. (white clover), Pisum sativum ssp. arvénse L. (gray pea) and Hordeum vulgare L. (barley) did not display the highest Ba concentrations, but showed the highest Ba uptake from soil. High plant uptake of calcium (Ca) also seemed to enhance Ba uptake, by legumes in particular. However, liming reduced shoot Ba concentrations, particularly of species with low affinity for Ca. The risk of Ba accumulation thus raises toxicity concerns when forage legumes are cultivated in soils containing elevated concentrations of Ba.

Sa1779 Soluble Plantain (Banana) Fibre Inhibits Epithelial Cell Damage in Response to Clostridium difficile and Its Toxins

G A A b st ra ct s fecal BA loss, which occurs in the absence of any absorptive defect within the terminal ileum, is due to increased BA synthesis, resulting from impaired FGF19 ileal production or hepatic actions. We aimed to investigate whether BA-induced expression of FGF19 in the ileum is reduced in patients with low SeHCAT retention.Methods: Patients being investigated for unexplained diarrhea (n=16) were prospectively recruited and gave informed consent at colonoscopy to give additional ileal biopsies. All had SeHCAT tests. Groups of 2-3 biopsies (explants) were incubated separately for 6h with either BA-free culture media (unstimulated controls), chenodeoxycholate (CDCA) or glyco-CDCA (GCDCA), both at 50uM. After RNA extraction and cDNA synthesis, FGF19 expression was quantified relative to GAPDH by RT-PCR. Results: SeHCAT 7d retention values were 15% in 9 who were normal diarrhea controls. Previous studies had shown no significant difference in baseline unstimulated FGF19 expression between these groups and this was confirmed with the unstimulated control samples (p=0.76). Median stimulation overall was 184-fold with CDCA and 373-fold with GCDCA. A positive correlation was found between SeHCAT retention and the magnitude of the fold change in FGF19 expression stimulated by either CDCA (r=0.50, n=16, p=0.02) or by GCDCA (r=0.76, n=7, p=0.02). These relationships were still present when the fold changes were normalized to the baseline FGF19 expression found in the unstimulated explants. Conclusion: Ileal explants from patients with lower SeHCAT 7d retention have a lower response to both CDCA and GCDCA. As uptake of GCDCA is dependent on carrier-mediated apical BA uptake but CDCA is not, this implies there is no defect in apical BA uptake, but abnormalities elsewhere in the FGF19 response. A reduced capacity to induce ileal FGF19 expression in response to absorbed BA is proposed to lead to the excess BA production and fecal BA losses found in primary BAD.

Interactions between Cs, Sr, and other nutrients and trace element accumulation in Amaranthus shoot in response to variety effect.

Aiming at clarifying the interactions between Cs, Sr, and other mineral elements in the genus Amaranthus, this study adopted 33 different varieties of Amaranthus and investigated the concentrations of 23 mineral elements in shoots grown in the fields of Iino in Fukushima prefecture. Significant varietal effects were detected for all elements except Se, and degree of interspecies variation was highly element dependent. Among 23 elements, amaranths were less sensitive to the accumulation of Cs and Sr than most other mineral elements to the species level. There are six elements showing significant correlation with Cs, positive correlations between As, Rb, Al, Fe, Ni, and Cs, and negative correlation between Ba and Cs. Significant correlations between Ca, Mg, Mn, Zn, B, Ba, Cd, and Sr were detected, and all of the coefficients were positive. Cs and Sr did not present significant correlation, but they were both significantly correlated with Ba. By principal component analysis (PCA), the first and second principal components (PC1 and PC2) accounted for 23.2 and 20.3% of the total variance and associated with Cs and Sr, respectively. Both of the two species took up more Cs by promoting the influx of elements positively correlated with Cs into shoot, but at the same time, Amaranthus hypochondriacus (L.) Mapes 847 decreased the K and Ba uptake and Amaranthus powellii (S. Wats) subsp. Powellii inhibited the accumulation of Rb, Sr, and significantly correlated elements of Sr in shoot. This study is the first to pave the way for comprehension on ionome in amaranth shoot at the variety level. The results of this research provide the ionomic basis for implementing countermeasures in the field against the translocation of Cs (and potentially Sr) toward crops and food.

Calcium Entry in Toxoplasma gondii and Its Enhancing Effect of Invasion-linked Traits

During invasion and egress from their host cells, Apicomplexan parasites face sharp changes in the surrounding calcium ion (Ca(2+)) concentration. Our work with Toxoplasma gondii provides evidence for Ca(2+) influx from the extracellular milieu leading to cytosolic Ca(2+) increase and enhancement of virulence traits, such as gliding motility, conoid extrusion, microneme secretion, and host cell invasion. Assays of Mn(2+) and Ba(2+) uptake do not support a canonical store-regulated Ca(2+) entry mechanism. Ca(2+) entry was blocked by the L-type Ca(2+) channel inhibitor nifedipine and stimulated by the increase in cytosolic Ca(2+) and by the specific L-type Ca(2+) channel agonist Bay K-8644. Our results demonstrate that Ca(2+) entry is critical for parasite virulence. We propose a regulated Ca(2+) entry mechanism activated by cytosolic Ca(2+) that has an enhancing effect on invasion-linked traits.

Three-way compositional analysis of water quality monitoring data

Water quality monitoring data typically consist of \(J\) parameters and constituents measured at \(I\) number of static locations at \(K\) sets of seasonal occurrences. The resulting \(I \times J \times K\) three-way array can be difficult to interpret. Additionally, the constituent portion of the dataset (e.g., major ion and trace element concentration, pH, etc.) is compositional in that it sums to a constant (e.g., 1 kg/L) and is mathematically confined to the simplex, the sample space for compositional data. Here we apply a Tucker3 model on centered log-ratio data to find low dimensional representation of latent variables as a means to simplify data processing and interpretation of three years of seasonal compositional groundwater chemistry data for 14 wells at a study site in Wyoming, USA. The study site has been amended with treated coalbed methane produced water, using a subsurface drip irrigation system, to allow for irrigation of forage crops. Results from three-way compositional data analysis indicate that primary controls on water quality at the study site include: solutes concentration by evapotranspiration, cation exchange, and dissolution of native salts. These findings agree well with results from more detailed investigations of the site. In addition, the model identified Ba uptake during gypsum precipitation in some portions of the site during the final 6–9 months of investigation, a process for which the timing and extent had not previously been identified. These results suggest that multi-way compositional analyses hold promise as a means to more easily interpret water quality monitoring data.

Environmental Records from Great Barrier Reef Corals: Inshore versus Offshore Drivers

The biogenic structures of stationary organisms can be effective recorders of environmental fluctuations. These proxy records of environmental change are preserved as geochemical signals in the carbonate skeletons of scleractinian corals and are useful for reconstructions of temporal and spatial fluctuations in the physical and chemical environments of coral reef ecosystems, including The Great Barrier Reef (GBR). We compared multi-year monitoring of water temperature and dissolved elements with analyses of chemical proxies recorded in Porites coral skeletons to identify the divergent mechanisms driving environmental variation at inshore versus offshore reefs. At inshore reefs, water Ba/Ca increased with the onset of monsoonal rains each year, indicating a dominant control of flooding on inshore ambient chemistry. Inshore multi-decadal records of coral Ba/Ca were also highly periodic in response to flood-driven pulses of terrigenous material. In contrast, an offshore reef at the edge of the continental shelf was subject to annual upwelling of waters that were presumed to be richer in Ba during summer months. Regular pulses of deep cold water were delivered to the reef as indicated by in situ temperature loggers and coral Ba/Ca. Our results indicate that although much of the GBR is subject to periodic environmental fluctuations, the mechanisms driving variation depend on proximity to the coast. Inshore reefs are primarily influenced by variable freshwater delivery and terrigenous erosion of catchments, while offshore reefs are dominated by seasonal and inter-annual variations in oceanographic conditions that influence the propensity for upwelling. The careful choice of sites can help distinguish between the various factors that promote Ba uptake in corals and therefore increase the utility of corals as monitors of spatial and temporal variation in environmental conditions.

Internal cycling of dissolved barium in water column of the Bay of Bengal

Dissolved barium concentrations in water column of the Bay of Bengal along the 87°E transect (~6°N to ~21°N) have been measured to track the dispersion of its large influx from the Ganga–Brahmaputra river system and the outflow to the equatorial Indian Ocean. A typical barium concentration–depth profile shows relatively higher Ba concentrations in surface waters (depth ≤5m) followed by a minimum in the depth interval ~50–150m and an increase at greater depth. The barium concentrations in surface waters (depth≤5m) of the Bay of Bengal vary from ~35nmol/kg at the southernmost station 0806 to ~113nmol/kg close to mouth of the Hooghly estuary (station 0816). The Ba data in upper layers (depth ≤100m), excluding the very high Ba at station 0816, generally show a strong and significant inverse correlation with salinity (R2=0.75; P<0.0001). This indicates the southward flow of dissolved Ba from the Ganga–Brahmaputra river system that also includes its contributions by particle release and submarine groundwater discharge. The subsurface Ba minimum found in this study are ubiquitous and most probably a result of Ba uptake on settling particulates. On the other hand, the Ba concentrations in deep waters (depth >500m) is controlled dominantly by water mixing as suggested by a very strong and significant inverse correlation with salinity (R2>0.95; P<0.0001). Exceptions to this conservative behavior are the “hot-spots” of dissolved Ba in bottom waters, which are probably resulted by the dissolution of sediments at and/or below the sediment–water interface.Attempts were made to budget the Ba abundance in the Bay of Bengal using a two box model approach; surface (top ~100m) and deep waters (below ~100m). Under the steady state the annual Ba influx from the Ganga–Brahmaputra river system seems to be balanced through its removal via sinking particulates as a result there is no lateral outflow of dissolved Ba from the Ganga–Brahmaputra to the equatorial Indian Ocean through top ~100m of the Bay of Bengal. Most of this sinking particulate Ba (~95%) is regenerated again in the lower box, preferentially in the intermediate waters ~100–500m. Therefore, frequently ventilated intermediate waters of the Bay of Bengal, receiving a large input of dissolved Ba through particle remineralization can be a significant source of dissolved Ba to the Indian Ocean.