Sodium Accumulation Research Articles

Diethyl aminoethyl hexanoate ameliorates salt tolerance associated with ion transport, osmotic adjustment, and metabolite reprograming in white clover

BackgroundSoil salinization is a serious environmental hazard, limiting plant growth and production in different agro-ecological zones worldwide. Diethyl aminoethyl hexanoate (DA-6) as an essential plant growth regulator (PGR) exhibits a beneficial role in improving crop growth and stress tolerance. However, the DA-6-regulated effect and mechanism of salt tolerance in plants are still not fully understood. The objective of current study was to disclose salt tolerance induced by DA-6 in relation to changes in water and redox balance, photosynthetic function, ionic homeostasis, and organic metabolites reprogramming in white clover (Trifolium repens).ResultsA prolonged duration of salt stress caused water loss, impaired photosynthetic function, and oxidative injury to plants. However, foliar application of DA-6 significantly improved osmotic adjustment (OA), photochemical efficiency, and cell membrane stability under salt stress. In addition, high salinity induced massive accumulation of sodium (Na), but decreased accumulation of potassium (K) in leaves and roots of all plants. DA-6-treated plants demonstrated significantly higher transcript levels of genes involved in uptake and transport of Na and K such as VP1, HKT8, SOS1, NHX2, NHX6, and SKOR in leaves as well as VP1, HKT1, HKT8, H+-ATPase, TPK5, SOS1, NHX2, and SKOR in roots. Metabolomics analysis further illustrated that DA-6 primarily induced the accumulation of glucuronic acid, hexanoic acid, linolenic acid, arachidonic acid, inosose, erythrulose, galactopyranose, talopyranose, urea, 1-monopalmitin, glycerol monostearate, campesterol, stigmasterol, and alanine.ConclusionsThe DA-6 significantly up-regulated transcript levels of multiple genes associated with increased Na+ compartmentalization in vacuoles and Na+ sequestration in roots to reduce Na+ transport to photosynthetic organs, thereby maintaining Na+ homeostasis under salt stress. The accumulation of many organic metabolites induced by the DA-6 could be attributed to enhanced cell wall and membrane structural stability and functionality, OA, antioxidant defense, and downstream signal transduction in leaves under salt stress. The present study provides a deep insight about the synergistic role of DA-6 in salt tolerance of white clover.

Deciphering the genetic basis of salinity tolerance in a diverse panel of cultivated and wild soybean accessions by genome-wide association mapping

Key messageIn a genome-wide association study involving 269 cultivated and wild soybean accessions, potential salt tolerance donors were identified along with significant markers and candidate genes, such as GmKUP6 and GmWRKY33.Salt stress remains a significant challenge in agricultural systems, notably impacting soybean productivity worldwide. A comprehensive genome-wide association study (GWAS) was conducted to elucidate the genetic underpinnings of salt tolerance and identify novel source of salt tolerance among soybean genotypes. A diverse panel comprising 269 wild and cultivated soybean accessions was subjected to saline stress under controlled greenhouse conditions. Phenotypic data revealed that salt tolerance of soybean germplasm accessions was heavily compromised by the accumulation of sodium and chloride, as indicated by highly significant positive correlations of leaf scorching score with leaf sodium/chloride content. The GWAS analysis, leveraging a dataset of 32,832 SNPs, unveiled 32 significant marker-trait associations (MTAs) across seven traits associated with salt tolerance. These markers explained a substantial portion of the phenotypic variation, ranging from 14 to 52%. Notably, 11 markers surpassed Bonferroni’s correction threshold, exhibiting highly significant associations with the respective traits. Gene Ontology enrichment analysis conducted within a 100 Kb range of the identified MTAs highlighted candidate genes such as potassium transporter 6 (GmKUP6), cation hydrogen exchanger (GmCHX15), and GmWRKY33. Expression levels of GmKUP6 and GmWRKY33 significantly varied between salt-tolerant and salt-susceptible soybean accessions under salt stress. The genetic markers and candidate genes identified in this study hold promise for developing soybean varieties resilient to salinity stress, thereby mitigating its adverse effects.

Butterfly species vary in sex‐specific sodium accumulation from larval diets

Abstract Sodium is essential for animals, and its heterogeneous distribution can cause a range of phenomena, from sodium‐seeking behaviours to impacting their performance. Although sodium content in soils and plants is relatively well documented, data for higher trophic levels are limited. Knowledge of the variation in sodium in lower trophic levels could have implications for understanding the behaviour and physiology of species at higher levels. We investigated the variation in tissue sodium concentration between males and females of four butterfly species. Puddling behaviour of Lepidoptera suggests sodium needs of males are generally greater than females, thus, we predicted males would accumulate more sodium than females on a given diet. Larvae were reared on plants (for Battus philenor, Chlosyne lacinia and Danaus plexippus) and an artificial diet (for Pieris rapae) under Low Na (no added sodium) and High Na (sodium added) conditions. Among species and sexes, we quantified and compared adult absolute tissue sodium concentrations and bioconcentration factors, which indicate net sodium accumulation or excretion relative to individuals' diets. On average, individuals on low‐sodium diets had higher bioconcentration values across all species. Male butterflies accumulated significantly higher sodium concentrations than females in two sodium treatments for B. philenor, and P. rapae and only in the High Na treatment for C. lacinia. However, in D. plexippus, individuals accumulate sodium in the High Na treatment, but males and females responded in the same way. Our study revealed sex‐ and species‐specific patterns of butterfly sodium accumulation, which could be linked to variations in behaviour and/or performance. Differences in sodium content across species have implications for variation in predation and trophic‐level interactions, an interesting avenue for future ecological and evolutionary research.

Rootstock Effects on Tomato Fruit Composition and Pollinator Preferences in Tomato

Food security is threatened by climate change and associated abiotic stresses that affect the flowering stage and the biochemistry of flowers and fruits. In tomato, managed insect pollination and grafting elite tomato varieties onto robust rootstocks are widely practiced commercially to enhance tomato crop profitability, particularly under suboptimal conditions. However, little is known about rootstock–pollinator interactions and their impact on the chemical composition of fruit. In this study, a commercial tomato F1 hybrid (Solanum lycopersicum L.) was self-grafted and grafted onto a set of experimental rootstocks and cultivated under optimal and saline (75 mM NaCl) conditions in the presence of managed bumblebee pollinators (Bombus terrestris). The number of visits (VN) and total visiting time (TVT) by pollinators to different grafted plants were monitored through an RFID (radio-frequency identification) tracking system, while targeted metabolites (hormones, sugars, and organic and amino acids) and mineral composition were analyzed in the fruit juice by UHPLC-MS and ICP-OES, respectively. Pollinator foraging decisions were influenced by the rootstocks genotype and salinity treatment. Experimental rootstocks predominantly increased pollinator attraction compared to the self-grafted variety. Interestingly, the pollinator parameters were positively associated with the concentration of abscisic acid, salicylic acid, malate and fumarate, and tyrosine in salinized fruits. Moreover, a high accumulation of sodium was detected in the fruits of the plants most visited by pollinators, while rootstock genotype-specific responses were found for nitrogen and potassium concentrations. In addition to the known effect on yield, these findings underscore the synergic interactions between rootstocks, pollinators, and environmental stressors on tomato fruit composition.

Zinc Seed Priming Alleviates Salinity Stress and Enhances Sorghum Growth by Regulating Antioxidant Activities, Nutrient Homeostasis, and Osmolyte Synthesis

Salinity is a serious abiotic stress that limits crop production and food security. Micronutrient application has shown promising results in mitigating the toxic impacts of salinity. This study assessed the impacts of zinc seed priming (ZSP) on the germination, growth, physiological and biochemical functioning of sorghum cultivars. The study comprised sorghum cultivars (JS-2002 and JS-263), salinity stress (control (0 mM) and 120 mM)), and control and ZSP (4 mM). Salinity stress reduced germination and seedling growth by increasing electrolyte leakage (EL: 60.65%), hydrogen peroxide (H2O2: 109.50%), malondialdehyde (MDA; 115.30%), sodium (Na), and chloride (Cl) accumulation and decreasing chlorophyll synthesis, relative water contents (RWC), total soluble proteins (TSPs), and potassium (K) uptake and accumulation. Nonetheless, ZSP mitigated the deleterious impacts of salinity and led to faster germination and better seedling growth. Zinc seed priming improved the chlorophyll synthesis, leaf water contents, antioxidant activities (ascorbate peroxide: APX, catalase: CAT, peroxidase: POD, superoxide dismutase: SOD), TSPs, proline, K uptake and accumulation, and reduced EL, MDA, and H2O2 production, as well as the accumulation of toxic ions (Na and Cl), thereby promoting better germination and growth. Thus, these findings suggested that ZSP can mitigate the toxicity of salinity by favoring nutrient homeostasis, antioxidant activities, chlorophyll synthesis, osmolyte accumulation, and maintaining leaf water status.

Characterisation of a major QTL for sodium accumulation in tomato grown in high salinity.

Soil salinity is a serious concern for tomato culture, affecting both yield and quality parameters. Although some genes involved in tomato salt tolerance have been identified, their genetic diversity has been rarely studied. In the present study, we assessed salt tolerance-related traits at juvenile and adult stages in a large core collection and identified salt tolerance quantitative trait loci (QTLs) by genome-wide association study (GWAS). The results suggested that a major QTL is involved in leaf sodium accumulation at both physiological stages. We were able to identify the underlying candidate gene, coding for a well-known sodium transporter, called SlHKT1.2. We showed that an eQTL for the expression of this gene in roots colocalized with the above ground sodium content QTL. A polymorphism putatively responsible for its variation was identified in the gene promoter. Finally, to extend the applicability of these results, we carried out the same analysis on a test-cross panel composed of the core collection crossed with a distant line. The results indicated that the identified QTL retained its functional impact even in a hybrid genetic context: this paves the way for its use in breeding programs aimed at improving salinity tolerance in tomato cultivars.

Manipulating Interfacial Renovation via In Situ Formed Metal Fluoride Heterogeneous Protective Layer toward Exceptional Durable Sodium Metal Anodes

AbstractSodium metal is regarded as an optimal anode material for high‐energy‐density sodium‐ion batteries (SIBs). However, during the processes of sodium deposition and stripping, the failure of the solid electrolyte interphase (SEI) film leads to the continuous accumulation of inactive sodium, thereby compromising the cycling reversibility of the battery. Here, a novel metal fluoride heterointerface layer is generated and constructed through in situ manipulation of the continuous reaction between TiF4 and metal Na. The reconstructed NaF/TiF3 interface layer, which tightly anchors the sodium metal, effectively suppresses the formation of sodium dendrites during the charge‐discharge process. The highly sodium‐philic TiF3 component exhibits strong binding with Na ions, while NaF reduces the Na+ diffusion energy barrier, significantly enhancing the reaction kinetics. Due to the successful artificial construction of this interface layer, the Na/TiF4 composite electrode demonstrates an exceptional ultra‐long cycling stability of 2370 h in symmetric cells (0.5 mAh cm−2). Density functional theory (DFT) calculations further validate the functionality of each component in the Na/TiF4 protective layer. When paired with NaNi1/3Fe1/3Mn1/3O2 cathode in a pouch cell, it exhibits stability up to 2000 cycles at current densities of 2 C and 4 C, with a maximum energy density output of 483.1 Wh kg−1 (power density: 320.8 W kg−1).

Evaluating phytoremediation potential and nutrients status of Bassia indica (Wight) A. J. Scott (Indian Bassia) in a cadmium-contaminated saline soil.

Bassia indica (Wight) A. J. Scott is a fast-growing halophyte suitable for the remediation of saline lands on a large scale. However, no information is available regarding its phytoremediation potential for cadmium (Cd) alone or in combination with salinity. Besides evaluating phytoremediation, assessing micronutrient hemostasis as a crucial physiological insight into the mechanism involved in the tolerance of B. indica under saline soil contaminated with Cd was subjected. Under salinity stress, a considerable amount of sodium accumulates in the plant. Moreover, the accumulation of sodium increased by Cd stress levels. The increase in the exchangeable form of Cd in the rhizosphere in the presence of NaCl ions further elevated the Cd content in the plant tissues. For instance, compared to non-saline conditions, applying 2.5 and 5 g NaCl kg-1 to soil treated with 60 mg Cd kg-1 increased exchangeable Cd by 28.4 and 49.5% in rhizosphere soil, which led to increased cadmium content by 16.1 and 29.6% in the root (as amainpart of Cd accumulation), respectively. Under most stress conditions, potassium homeostasis in the shoot remained undisturbed. It was observed that this plant could transfer an optimal level of potassium from the roots to the shoots at a moderate salinity level. Changes and the distribution of Cu and Zn levels followed a similar pattern in the plant, indicating a common regulation mechanism for these nutrients. Generally, the plant could maintain an appropriate level of Fe, Zn, and Cu ions under most stressed conditions. However, the level of Mn decreased significantly under severe stress levels. Growth parameters, tolerance index, and the values of translocation factor < 1 and shoot bioconcentration factor > 1 under 5 mg Cd kg-1 soil treatment at different salinity levels indicated that B. indica could mitigate the detrimental effect of Cd toxicity and tolerate the NaCl stress via a phytostabilizer mechanism. However, the shoot bioconcentration factor values were very close to one at other Cd levels. Therefore, considering the obtained evidence and the innate ability of B. indica to remediation salinity, this plant is still recommended, even for higher Cd levels (even until 30 mg kg-1), in the presence of salinity.

Enhancing tomato plants' tolerance to combined heat and salt stress – The role of arbuscular mycorrhizae and biochar

The Mediterranean basin is highly susceptible to climate change, with soil salinization and the increase in average temperatures being two of the main factors affecting crop productivity in this region. Following our previous studies on describing the detrimental effects of heat and salt stress co-exposure on tomato plants, this study aimed to understand if substrate supplementation with a combination of arbuscular mycorrhizal fungi (AMF) and biochar could mitigate the negative consequences of these stresses. Upon 21 days of exposure, stressed tomato plants grown under supplemented substrates showed increased tolerance to heat (42 °C for 4 h/day), salt (100 mM NaCl), and their combination, presenting increased biomass and flowering rate. The beneficial effects of AMF and biochar were associated with a better ionic balance (i.e. lower sodium accumulation and higher uptake of calcium and magnesium) and increased photosynthetic efficiency. Indeed, these plants presented higher chlorophyll content and improved CO2 assimilation rates. Biochemical data further supported that tomato plants grown with AMF and biochar were capable of efficiently modulating their defence pathways, evidenced by the accumulation of proline, ascorbate, and glutathione, coupled with a lower dependency on energy-costly enzymatic antioxidant players. In summary, the obtained data strongly point towards a beneficial role of combined AMF and biochar as sustainable tools to improve plant growth and development under a climate change scenario, where soil salinization and heat peaks often occur together.

Mechanistic study of inhibitory peptides with SHP-1 in hypertonic environment for infection model

Cutaneous Leishmaniasis, an infectious disease is globally the most prevalent form of leishmaniasis accounting for approximately 1 million cases every year as per world health organization. Infected individuals develop skin lesion which has been reported to be infiltrated by immune cells and parasite with high sodium accumulation creating hypertonic environment. In our work, we tried to mimic the hypertonic environment in virtual environment to study dynamicity of SHP-1 and NFAT5 along with their interactions through molecular dynamics simulation. We validated the SHP-1 and NFAT5 dynamics in infection and HSD conditions to study the impact of hypertonicity derived NFAT5 mediated response to L.major infection. We also evaluated our therapeutic peptides for their binding to SHP-1 and to form stable complex. Membrane stability with the peptides was analyzed to understand their ability to sustain mammalian membrane. We identified PepA to be a potential candidate to interact with SHP-1. Inhibition of SHP-1 through PepA to discern IL-10 and IL-12 reciprocity may be assessed in future and furnish us with a potential therapeutic molecule. HSD mice exhibited high pro-inflammatory response to L.major infection which resulted in reduced lesion size. Contrary to observations in HSD mice, infection model exhibited low pro-inflammatory response and increased lesion size with high parasite load. Thus, increase in NFAT5 expression and reduced SHP-1 expression may result in disease resolving effect which can be further studied through incorporation of synthetic circuit using PepA to modulate IL-10 and IL-12 reciprocity.

Intermuscular adipose tissue accumulation is associated with higher tissue sodium in healthy individuals.

High tissue sodium accumulation and intermuscular adipose tissue (IMAT) are associated with aging, type 2 diabetes, and chronic kidney disease. In this study, we aim to investigate whether high lower-extremity tissue sodium accumulation relates to IMAT quantity and whether systemic inflammatory mediators and adipocytokines contribute to such association. Tissue sodium content and IMAT accumulation (percentage of IMAT area to muscle area) were measured in 83 healthy individuals using sodium imaging (23Na-MRI) and proton (1H-MRI) imaging of the calf. Insulin sensitivity was assessed by glucose disposal rate (GDR) measured with the hyperinsulinemic-euglycemic clamp. Median (interquartile range) muscle and skin sodium contents were 16.6 (14.9, 19.0) and 12.6 (10.9, 16.7) mmol/L, respectively. Median IMAT was 3.69 (2.80, 5.37) %. In models adjusted for age, sex, BMI, GDR, adiponectin, and high-sensitivity C-reactive protein, increasing tissue sodium content was significantly associated with higher IMAT quantity (p = 0.018 and 0.032 for muscle and skin tissue sodium, respectively). In subgroup analysis stratified by sex, skin sodium was significantly associated with IMAT only among men. In interaction analysis, the association between skin sodium and IMAT was greater with increasing levels of high-sensitivity C-reactive protein and interleukin-6 (p for interaction = 0.022 and 0.006, respectively). Leg muscle and skin sodium are associated with IMAT quantity among healthy individuals. The relationship between skin sodium and IMAT may be mediated by systemic inflammation.

#2707 Prediction of plasma sodium changes in hypernatremic patients: the role of tissue sodium content

Abstract Background and Aims Hypo- and hypernatremia are frequently encountered electrolyte disturbances in clinical practice. Rapid correction of these dysnatremias can result in severe neurological complications. Therefore, various formulas have been developed to predict changes in plasma sodium concentration ([Na+]) after treatment. However, these kidney-centered formulas have been shown to be inaccurate. A potential explanation for the discrepancy between predicted and measured plasma [Na+] is the accumulation of sodium in the skin, which is not explicitly taken into account in these formulas. The purpose of this post-hoc analysis is to evaluate the association between factors related to tissue sodium accumulation and the discrepancy between measured and predicted plasma [Na+]. Method We used data from a hypernatremic intensive care unit (ICU) cohort with 66 patients and 1,034 ICU days with complete data on sodium, potassium and water balance. We excluded ICU days with incomplete balances, dialysis and severe diarrhea. The predicted plasma [Na+] was calculated using the Barsoum-Levine (BL) and the Nguyen-Kurtz (NK) formula. Then, we calculated the discrepancy between predicted and measured plasma [Na+] (∆[Na+]). We fitted a linear mixed-effect model to investigate the association between factors related to tissue sodium content and ∆[Na+]. Age, sex, blood pressure, eGFR, CRP, plasma albumin, total body water (TBW), baseline plasma [Na+] and changes in plasma [Na+] were incorporated as fixed effects in the model, while the subjects were introduced as a random effect. TBW was estimated as 60% of body weight for males and 50% of body weight for females, corrected for fluid balances on subsequent ICU days. Results A total of 613 ICU days of 66 patients were included in our analysis. The mean age was 58 ± 15 years and 38% was female. The mean plasma [Na+] at inclusion day was 145 ± 9 mmol/L and mean eGFR CKD-EPI was 52 ± 28 ml/min/1.73 m2. On average, the deviation between predicted and measured plasma [Na+] was 3.8 ± 3.3 mmol/L for the BL formula and 3.9 ± 3.4 mmol/L for the NK formula. For both formulas, TBW (p = 0.01), baseline plasma [Na+] (p &amp;lt; 0.001) and plasma [Na+] change (p &amp;lt; 0.001) were significantly associated with the discrepancy between predicted and measured plasma [Na+] (Table 1). Plasma albumin (p = 0.02) was also significantly associated with this discrepancy when the NK formula was used. Conclusion In a hypernatremic ICU cohort, baseline plasma [Na+], estimated TBW and plasma [Na+] changes are associated with the inaccurateness of plasma [Na+] prediction. As baseline plasma [Na+] and estimated TBW are available when initiating treatment, incorporation of these variables in the currently available formulas may improve the prediction of plasma [Na+].

#2651 Microwave tissue digestion and flame atomic absorption spectroscopy for measuring tissue sodium content in CKD patients

Abstract Background and Aims Skin and muscle sodium accumulation has been demonstrated in CKD patients and may contribute to progression of the disease. Various methods are available for measuring tissue sodium content. However, the accuracy and reproducibility of these methods remain unknown. Dry ashing is the most used digestion method, but is expensive, time consuming and has a risk of incomplete digestion. This study compared microwave digestion, dry ashing, and two electrolyte quantification methods for quantifying tissue sodium and potassium. Method We compared microwave digestion (Ethos LEAN Compact Microwave Digestion System, Milestone SRL) and dry ashing (Nabertherm S27) as sample preparation methods, and flame atomic absorption spectroscopy (FAAS, Model 425 Flame Photometer, Sherwood Scientific) and inductively coupled plasma optical emission spectrometry (ICP-OES, Varian 720-ES, Varian Inc.) as electrolyte quantification methods. Skin and muscle samples were obtained from rats and mice, and human skin samples were used. Tissues biopsies were cut in three pieces and digested separately. The methods were compared using interclass correlation coefficient (ICC) and Bland-Altman analysis. The third piece of tissue was microwave-digested by another operator to test inter-operator reproducibility by calculating the ICC and absolute overall mean difference. Results With microwave digestion and FAAS median (IQR) human skin concentration was 114.8 (99.2-157.0, n = 12) mmol/L, confirming tissue sodium storage. When including all tissues, FAAS and ICP-OES showed high agreement for sodium (ICC 0.98, bias –0.00008 mmol/g, n = 141 and potassium (ICC 0.98, bias –0.005 mmol/g, n = 141). Microwave digestion and ashing showed agreement for sodium (ICC 0.93, bias –0.002 mmol/g, n = 61) and potassium (ICC 0.93, bias –0.02 mmol/g, n = 61). The inter-operator agreement was good for sodium (ICC 0.95, absolute mean difference (SD) 0.044 mmol/g (0.073), n = 70) and potassium (ICC 0.96, absolute mean difference (SD) 0.031 mmol/g (0.032), n = 70). Conclusion Microwave digestion with FAAS is a reliable and consistent method for sodium and potassium trace analysis in animal and human tissues compared to ashing and ICP-OES, respectively. This method showed more quantification of cations than the most frequently reported method, representing an easier, and less time-consuming way to quantify tissue sodium in CKD research.

Energetic dysfunction and iron overload in early Parkinson's disease: Two distinct mechanisms?

IntroductionIdentifying biomarkers reflecting cellular dysfunctions in early Parkinson's disease patients (ePD) is needed to develop targeted therapeutic strategies. We aimed to determine if cellular energetic dysfunction related to increased brain sodium concentration would be co-located to microstructural alterations and iron deposition in ePD. MethodsWe prospectively included 12 ePD (mean disease duration 20.0 ± 10.2 months) and 13 healthy controls (HC), scanned with a 7 T 1H and 23Na MRI. Complementary voxel-based and region-based assessments were performed, the latter utilizing a high-resolution multimodal template we created (combining quantitative T1 maps (qT1), transverse relaxation rate (R2*), quantitative magnetic susceptibility mapping (QSM) images) from 200 subjects. This template allowed a precise multiparametric assessment of sodium concentration, QSM, R2*, qT1, mean diffusivity, and fractional anisotropy values. A two-sided p-value<0.05 was considered statistically significant after the Bonferroni correction. ResultsRelative to HC, ePD showed significantly higher sodium concentration in left Substantia nigra (SN) pars reticulata (46.13 mM ± 3.52 vs 38.60 mM ± 6.10, p = 0.038), a subpart of the SN pars compacta (SNc) and ventral tegmental area, Putamen, Globus Pallidum external, accumbens nucleus and claustrum. Significantly increased QSM and R2* values, and decreased T1 values, were limited to the Nigrosomes 1 (Nig) and right SNc (all p < 0.05). QSM values in the Nig were significantly correlated to UPDRS-III scores (r = 0.91,p < 0.001). ConclusionIn ePD, brain sodium accumulation was broad and dissociated from iron accumulation. As with iron accumulation, a sodium-related pathophysiological approach could lead to identifying potential new therapeutic agents and deserves further investigation.

Salicylic Acid and Calcium Chloride Seed Priming: A Prominent Frontier in Inducing Mineral Nutrition Balance and Antioxidant System Capacity to Enhance the Tolerance of Barley Plants to Salinity.

The current investigation aims to underline the impact of salicylic acid or calcium chloride seed pre-treatments on mineral status and oxidative stress markers, namely levels of electrolyte leakage (EL) and lipid peroxidation levels, measured as thiobarbituric reactive substances (TBARS), and the activity of some antioxidant enzymes in roots and leaves of plants in two barley species grown under various salt treatments. Overall, our results revealed that salinity inhibits essential nutrient absorption such as iron, calcium, magnesium and potassium and stimulates the absorption of sodium. Also, this environmental constraint induced oxidative stress in plants in comparison with the control conditions. This state of oxidative stress is reflected by an increase in TBARS content as well as the stimulation of EL values. In addition, salinity induced disturbances in the activity of antioxidant enzymes, which were mainly dependent on the applied salt concentration and the species. In addition, Hordeum marinum maintained high antioxidant enzyme activity and low levels of oxidative stress parameters, which reinforces its salt-tolerant character. Importantly, salicylic acid or calcium chloride seed priming alleviated the mineral imbalance and the oxidative damage induced by salinity. Moreover, seed priming improves iron, calcium magnesium and potassium content and limitsthe accumulation of sodium. Also, both treatments not only decrease TBARS levels and limit EL, but they also stimulate the antioxidant enzyme activities in the leaves and roots of the stressed plants as compared with stressed plants grown from non-primed seeds. Interestingly, the beneficial effects of the mentioned treatments were more notable on Hordeum vulgare species.

Sodium removal per ultrafiltration volume in automated peritoneal dialysis in pediatric patients.

The standard rate of sodium removal in adult anuric patients on continuous ambulatory peritoneal dialysis (CAPD) is 7.5g/L of ultrafiltration volume (UFV). Although automated PD (APD) is widely used in pediatric patients, no attempt has yet been made to estimate sodium removal in APD. The present, retrospective cohort study included pediatric patients with APD who were managed at Tokyo Metropolitan Children's Medical Center between July 2010 and November 2017. The patients underwent a peritoneal equilibrium test (PET) at our hospital. Sodium removal per UFV was calculated by peritoneal function and dwell time using samples from patients on APD with 1- and 2-h dwell effluent within three months of PET and 4- and 10-h dwell effluent at PET. In total, 217 samples from 18 patients were included, with 63, 81, and 73 of the samples corresponding to the High [H], High-average [HA], and Low-average [LA] PET category, respectively. Sodium removal per UFV (g/L in salt equivalent) for dwell times of one, two, four, and ten hours was 5.2, 8.8, 8.0, and 11.5 for PET [H], 5.3, 5.8, 5.6, and 8.1 for PET [HA], and 4.6, 5.1, 5.1, and 7.1 for PET [LA], respectively. Sodium removal per UFV in pediatric APD was less than the standard adult CAPD and tended to be lower with shorter dwell times, leading to sodium accumulation. Therefore, salt intake should be restricted in combination with one or more long daytime dwells, especially in anuric patients.

MICROWAVE TISSUE DIGESTION AND FLAME ATOMIC ABSORPTION SPECTROSCOPY FOR MEASURING TISSUE SODIUM CONTENT IN HYPERTENSIVE AND CARDIOVASCULAR RISK PATIENTS

Objective: Skin sodium accumulation has been demonstrated in hypertensive patients and may contribute to the pathophysiology of hypertension. Various methods are available for measuring tissue sodium content. However, the accuracy and reproducibility of these methods remain unknown. Dry ashing is the most used digestion method, but is expensive, time consuming and has a risk of incomplete digestion. This study compared microwave digestion, dry ashing, and two electrolyte quantification methods for quantifying tissue sodium and potassium. Design and method: We compared microwave digestion (Ethos LEAN Compact Microwave Digestion System, Milestone SRL) and dry ashing (Nabertherm S27) as sample preparation methods, and flame atomic absorption spectroscopy (FAAS, Model 425 Flame Photometer, Sherwood Scientific) and inductively coupled plasma optical emission spectrometry (ICP-OES, Varian 720-ES, Varian Inc.) as electrolyte quantification methods. Skin and muscle samples were obtained from rats and mice, and human skin samples were used. Tissues biopsies were cut in three pieces and digested separately. The methods were compared using interclass correlation coefficient (ICC) and Bland-Altman analysis. The third piece of tissue was microwave-digested by another operator to test inter-operator reproducibility by calculating the ICC and absolute overall mean difference. Results: With microwave digestion and FAAS median (IQR) human skin concentration was 114.8 (99.2-157.0, n=12) mmol/L, confirming tissue sodium storage. When including all tissues, FAAS and ICP-OES showed high agreement for sodium (ICC 0.98, bias -0.00008 mmol/g, n=141 and potassium (ICC 0.98, bias -0.005 mmol/g, n=141). Microwave digestion and ashing showed agreement for sodium (ICC 0.93, bias -0.002 mmol/g, n=61) and potassium (ICC 0.93, bias -0.02 mmol/g, n=61). The inter-operator agreement was good for sodium (ICC 0.95, absolute mean difference (SD) 0.044 mmol/g (0.073), n=70) and potassium (ICC 0.96, absolute mean difference (SD) 0.031 mmol/g (0.032), n=70). Conclusions: Microwave digestion with FAAS is a reliable and consistent method for sodium and potassium trace analysis in animal and human tissues compared to ashing and ICP-OES, respectively. This method showed more quantification of cations than the most frequently reported method, representing an easier, and less time-consuming way to quantify tissue sodium in hypertension and cardiovascular research.

Accumulation of Sodium and Iron in Solanum Tuberosum Under Care and Foliar Feeding

Accumulation of Sodium and Iron in Solanum Tuberosum Under Care and Foliar Feeding

Nanopriming with selenium doped carbon dots improved rapeseed germination and seedling salt tolerance

Soil salinity is a big environmental issue affecting crop production. Although seed nanopriming has been widely used to improve seed germination and seedling growth under salinity, our knowledge about the underlying mechanisms is still insufficient. Herein, we newly synthesized selenium-doped carbon dots nanoparticles coated with poly acrylic acid (poly acrylic acid coated selenium doped carbon dots, PAA@Se-CDs) and used it to prime seeds of rapeseeds. The TEM (transmission electron microscope) size and zeta potential of PAA@Se-CDs are 3.8 ± 0.2 nm and −30 mV, respectively. After 8 h priming, the PAA@Se-CDs nanoparticles were detected in the seed compartments (seed coat, cotyledon, and radicle), while no such signals were detected in the NNP (no nanoparticle control) group (SeO2 was used as the NNP). Nanopriming with PAA@Se-CDs nanoparticles increased rapeseeds germination (20%) and seedling fresh weight (161%) under saline conditions compared to NNP control. PAA@Se-CDs nanopriming significantly enhanced endo-β-mannanase activities (255% increase, 21.55 µmol h−1 g−1 vs. 6.06 µmol h−1 g−1, at DAS 1 (DAS, days after sowing)), total soluble sugar (33.63 mg g−1 FW (fresh weight) vs. 20.23 mg g−1 FW) and protein contents (1.96 µg g−1 FW vs. 1.0 µg g−1 FW) to support the growth of germinating seedlings of rapeseeds under salt stress, in comparison with NNP control. The respiration rate and ATP content were increased by 76% and 607%, respectively. The oxidative damage of salinity due to the over-accumulation of reactive oxygen species (ROS) was alleviated by PAA@Se-CDs nanopriming by increasing the antioxidant enzyme activities (SOD (superoxide dismutase), POD (peroxidase), and CAT (catalase)). Another mechanism behind PAA@Se-CDs nanopriming improving rapeseeds salt tolerance at seedling stage was reducing sodium (Na+) accumulation and improving potassium (K+) retention, hence increasing the K+/Na+ ratio under saline conditions. Overall, our results not only showed that seed nanopriming with PAA@Se-CDs could be a good approach to improve salt tolerance, but also add more knowledge to the mechanism behind nanopriming-improved plant salt tolerance at germination and early seedling growth stage.

Three-dimensional faveolate porous N-doped carbon skeleton embodied with nano Bi toward stable less-Na sodium metal batteries

Sodium metal batteries (SMBs) have been widely investigated recently due to the low price of Na metal, satisfactory energy density and similar chemical properties to lithium. However, SMBs also face challenges like low Na utilization, dendrite growth, dead sodium accumulation, unstable solid electrolyte interphase and massive bubble generation. To improve their safety and cycling stability, herein, we fabricate a porous hybrid framework, i.e., fine Bi nanoparticles anchored in porous N-doped carbon matrix (Bi@PNC), as a modified layer upon Cu collector toward stable SMBs. Upon electrochemical activation, the nanoscale Bi-derived Na–Bi alloy with high sodiophilicity reduces the nucleation overpotential of Na, inhibits the formation of Na dendrites, and decreases the loss of Na during cycling. Thanks to these striking merits, the half cells assembled with Na undergo 1600 cycles (3200 h) at 1 mA cm−2, 1 mAh cm−2 with the average Coulombic efficiency of 99.95%. The optimized Bi@PNC based symmetric cells still maintain the overpotential of ∼9.2 mV under 1 mA cm−2 and depth of discharge of 16.7% after cycling for 2420 h. Furthermore, the assembled less-Na full SMBs exhibit superb electrochemical properties. Our strategy here provides meaningful avenue to construct stable less-Na metallic anodes for advanced SMBs.