Association between sodium and potassium intake levels and body compositions of Chinese college students.

BACKGROUND AND OBJECTIVES: To investigate the relationship between sodium (Na) and potassium (K) nutritional condition and body compositions in youth aiming to give target population reasonable diet recommendations. METHODS AND STUDY DESIGN: The cross-sectional study was conducted involving 512 healthy youth aged 18 to 31 years from universities in Beijing. Food frequency questionnaire (FFQ) and bioelectrical impedance analyzer (BIA) were used to collect dietary intake information and body compositions. RESULTS: There was an increasing tendency in fat-related indicators and muscle-related indicators of the dietary Na tertile group (p <0.05). Additionally, Weight, body mass index (BMI), waist circumference (WC), and muscle-related indicators increased with the dietary K tertile group (p <0.05). Across increasing tertiles of dietary Na intake, the odds ratio (OR) was increased significantly (p < 0.05) in fat-related indicators. On the contrary, with the increased dietary Na intake, the OR decreased (p < 0.05) in appendicular skeletal muscle mass index (ASMI) and body lean mass. As tertiles of dietary K intake increased, the OR in both skeletal muscle mass index (SMMI) and lean mass index (LMI) decreased. CONCLUSIONS: High dietary Na is a risk factor for abnormal lipid distribution in college students. High dietary K can maintain skeletal muscle mass and reduce the risk of obesity. Na in the diet has a greater impact on the body composition of young people than K. Low dietary Na and high dietary K still need to be strengthened in science popularization and practice among more college students.

Integration of QTL Mapping and Whole Genome Sequencing Identifies Candidate Genes for Alkalinity Tolerance in Rice (Oryza sativa).

Soil alkalinity is an important stressor that impairs crop growth and development, resulting in reduced crop productivity. Unlike salinity stress, research efforts to understand the mechanism of plant adaptation to alkaline stress is limited in rice, a major staple food for the world population. We evaluated a population of 193 recombinant inbred lines (RIL) developed from a cross between Cocodrie and N22 under alkaline stress at the seedling stage. Using a linkage map consisting of 4849 SNP markers, 42 additive QTLs were identified. There were seven genomic regions where two or more QTLs for multiple traits colocalized. Three important QTL clusters were targeted, and several candidate genes were identified based on high impact variants using whole genome sequences (WGS) of both parents and differential expression in response to alkalinity stress. These genes included two expressed protein genes, the glucan endo-1,3-beta-glucosidase precursor, F-box domain-containing proteins, double-stranded RNA-binding motif-containing protein, aquaporin protein, receptor kinase-like protein, semialdehyde hydrogenase, and NAD-binding domain-containing protein genes. Tolerance to alkaline stress in Cocodrie was most likely due to the low Na+/K+ ratio resulting from reduced accumulation of Na+ ions and higher accumulation of K+ in roots and shoots. Our study demonstrated the utility of integrating QTL mapping with WGS to identify the candidate genes in the QTL regions. The QTLs and candidate genes originating from the tolerant parent Cocodrie should be targeted for introgression to improve alkalinity tolerance in rice and to elucidate the molecular basis of alkali tolerance.

Nanoceria seed priming enhanced salt tolerance in rapeseed through modulating ROS homeostasis and α-amylase activities.

BACKGROUND: Salinity is a big threat to agriculture by limiting crop production. Nanopriming (seed priming with nanomaterials) is an emerged approach to improve plant stress tolerance; however, our knowledge about the underlying mechanisms is limited. RESULTS: Herein, we used cerium oxide nanoparticles (nanoceria) to prime rapeseeds and investigated the possible mechanisms behind nanoceria improved rapeseed salt tolerance. We synthesized and characterized polyacrylic acid coated nanoceria (PNC, 8.5 ± 0.2 nm, -43.3 ± 6.3 mV) and monitored its distribution in different tissues of the seed during the imbibition period (1, 3, 8 h priming). Our results showed that compared with the no nanoparticle control, PNC nanopriming improved germination rate (12%) and biomass (41%) in rapeseeds (Brassica napus) under salt stress (200 mM NaCl). During the priming hours, PNC were located mostly in the seed coat, nevertheless the intensity of PNC in cotyledon and radicle was increased alongside with the increase of priming hours. During the priming hours, the amount of the absorbed water (52%, 14%, 12% increase at 1, 3, 8 h priming, respectively) and the activities of α-amylase were significantly higher (175%, 309%, 295% increase at 1, 3, 8 h priming, respectively) in PNC treatment than the control. PNC primed rapeseeds showed significantly lower content of MDA, H2O2, and •O2- in both shoot and root than the control under salt stress. Also, under salt stress, PNC nanopriming enabled significantly higher K+ retention (29%) and significantly lower Na+ accumulation (18.5%) and Na+/K+ ratio (37%) than the control. CONCLUSIONS: Our results suggested that besides the more absorbed water and higher α-amylase activities, PNC nanopriming improves salt tolerance in rapeseeds through alleviating oxidative damage and maintaining Na+/K+ ratio. It adds more knowledge regarding the mechanisms underlying nanopriming improved plant salt tolerance.

Handgrip Strength and Its Association With Hydration Status and Urinary Sodium-to-Potassium Ratio in Older Adults.

Objective: Older adults present higher risk of functional disability detected by handgrip strength and an increased risk of poor health conditions, such as dehydration and low values of the sodium-to-potassium (Na/K) ratio. This study aimed to quantify the association of hydration status and Na/K ratio with handgrip strength, based on the urinary excretion of older adults.Methods: A cross-sectional study was conducted in 735 older adults ≥ 65 years old. Handgrip strength was measured with a Jamar Dynamometer and low values were defined according to body mass index and to sex-specific cutoff points. The hydration status was evaluated based on free water reserve. Sodium and potassium intake were evaluated after converting 24-hour urinary sodium and potassium excretion, respectively. A logistic regression model was used to estimate the probability of presenting low handgrip strength, according to risk of hypohydration and to quartiles of Na/K, stratified by sex and adjusted for potential confounders.Results: The adjusted odds ratio (OR) for presenting low handgrip strength was higher in women at risk of hypohydration, but this association was not found in men. Both women and men with the highest values of Na/K ratio presented higher adjusted OR for low handgrip strength (OR in women was 2.03; 95% confidence interval [CI]: 1.12-3.68, and in men was 2.19; 95% CI: 1.11-4.29).Conclusions: The risk of hypohydration was directly associated with low handgrip strength in older women. In older adults, higher values of urinary Na/K ratio were also directly associated with low handgrip strength.

Correlation between Na/K ratio and electron densities in blood samples of breast cancer patients.

The main purpose of this study was to investigate the relationship between the electron densities and Na/K ratio which has important role in breast cancer disease. Determinations of sodium and potassium concentrations in blood samples performed with inductive coupled plasma-atomic emission spectrometry. Electron density values of blood samples were determined via ZXCOM. Statistical analyses were performed for electron densities and Na/K ratio including Kolmogorov-Smirnov normality tests, Spearman's rank correlation test and Mann-Whitney U test. It was found that the electron densities significantly differ between control and breast cancer groups. In addition, statistically significant positive correlation was found between the electron density and Na/K ratios in breast cancer group.

The relationship of health/food literacy and salt awareness to daily sodium and potassium intake among a workplace population in Switzerland.

BACKGROUND AND AIMS: High sodium (Na) and low potassium (K) intake are associated with hypertension and CVD risk. This study explored the associations of health literacy (HL), food literacy (FL), and salt awareness with salt intake, K intake, and Na/K ratio in a workplace intervention trial in Switzerland. METHODS AND RESULTS: The study acquired baseline data from 141 individuals, mean age 44.6 years. Na and K intake were estimated from a single 24-h urine collection. We applied validated instruments to assess HL and FL, and salt awareness. Multiple linear regression was used to investigate the association of explanatory variables with salt intake, K intake, and Na/K. Mean daily salt intake was 8.9 g, K 3.1 g, and Na/K 1.18. Salt intake was associated with sex (p < 0.001), and K intake with sex (p < 0.001), age (p = 0.02), and waist-to-height ratio (p = 0.03), as was Na/K. HL index and FL score were not significantly associated with salt or K intake but the awareness variable "salt content impacts food/menu choice" was associated with salt intake (p = 0.005). CONCLUSION: To achieve the established targets for population Na and K intake, health-related knowledge, abilities, and skills related to Na/salt and K intake need to be promoted through combined educational and structural interventions. Clinical Trials Registry number: DRKS00006790 (23/09/2014).

TaPUB1, a Putative E3 Ligase Gene from Wheat, Enhances Salt Stress Tolerance in Transgenic Nicotiana benthamiana.

High salinity is one of the most severe environmental stresses and limits the growth and yield of diverse crop plants. We isolated a gene named TaPUB1 from wheat (Triticum aestivum L. cv HF9703) that encodes a novel protein containing a U-box domain, the precursor RNA processing 19p (Prp19) superfamily and WD-40 repeats. Real-time reverse transcription-PCR analysis showed that TaPUB1 transcript accumulation was up-regulated by high salinity, drought and phytohormones, suggesting that it plays a role in the abiotic-related defense response. We overexpressed TaPUB1 in Nicotiana benthamiana to evaluate the function of TaPUB1 in the regulation of the salt stress response. Transgenic N. benthamiana plants (OE) with constitutively overexpressed TaPUB1 under the control of the Cauliflower mosaic virus 35S (CaMV 35S) promoter exhibited a higher germination rate, less growth inhibition, less Chl loss and higher photosynthetic capacity than wild-type (WT) plants under salt stress conditions. These results demonstrated the increased tolerance of OE plants to salt stress compared with the WT. The OE plants had lower osmotic potential (OP), reduced Na+ toxicity and less reactive oxygen species accumulation compared with the WT, which may be related to their higher level of osmolytes, lower Na+/K+ ratio and higher antioxidant enzyme activities under salt stress conditions. Consistent with these results, the up-regulated expression of osmic- and antioxidant-related genes in OE plants indicated a role for TaPUB1 in plant salt tolerance.

SbHKT1;4, a member of the high-affinity potassium transporter gene family from Sorghum bicolor, functions to maintain optimal Na⁺ /K⁺ balance under Na⁺ stress.

In halophytic plants, the high-affinity potassium transporter HKT gene family can selectively uptake K⁺ in the presence of toxic concentrations of Na⁺. This has so far not been well examined in glycophytic crops. Here, we report the characterization of SbHKT1;4, a member of the HKT gene family from Sorghum bicolor. Upon Na⁺ stress, SbHKT1;4 expression was more strongly upregulated in salt-tolerant sorghum accession, correlating with a better balanced Na⁺ /K⁺ ratio and enhanced plant growth. Heterogeneous expression analyses in mutants of Saccharomyces cerevisiae and Arabidopsis thaliana indicated that overexpressing SbHKT1;4 resulted in hypersensitivity to Na⁺ stress, and such hypersensitivity could be alleviated with the supply of elevated levels of K⁺, implicating that SbHKT1;4 may mediate K⁺ uptake in the presence of excessive Na⁺. Further electrophysiological evidence demonstrated that SbHKT1;4 could transport Na⁺ and K⁺ when expressed in Xenopus laevis oocytes. The relevance of the finding that SbHKT1;4 functions to maintain optimal Na⁺ /K⁺ balance under Na⁺ stress to the breeding of salt-tolerant glycophytic crops is discussed.

Assessment of the Diuretic Effect of the Leaves of Cucumis Dipsaceus Ehrenb (Cucurbitaceae) in Rats: Using Aqueous and 80% Methanol Extracts.

Background: The diuretic activity of the Cucumis dipsaceus leaf, which is used in indigenous medicine, has been claimed but has not yet undergone scientific evaluation. Objective: The objective of this study was to assess the diuretic activity of the aqueous and 80% methanol extracts derived from the leaves of Cucumis dipsaceus in rats. Methods: For the extraction process, the maceration technique was employed to obtain the aqueous and 80% methanol extracts from the Cucumis dipsaceus leaves. Male rats were then divided randomly into eight groups, with six rats in each group. These groups consisted of a negative control group, a positive control group, and three different groups for each extract at varying doses. The urine output volumes, the concentrations of urinary electrolytes (sodium, potassium, and chloride) and urinary pH, were measured and analysed to compare the results among the different groups. Results: Both the aqueous and 80% methanol extracts of Cucumis dipsaceus leaves demonstrated a significant increase in urinary output at doses of 200mg/kg body weight (p<0.01) and 400mg/kg body weight (p<0.001). When comparing the urinary electrolyte excretion with the negative control group, the groups treated with the 400mg/kg body weight dose of the aqueous extract showed significant differences in the urinary excretion of sodium (p<0.05), chloride (p<0.01), and K+ (p<0.01). Similarly, the urinary excretion of K+ and Cl- also exhibited significant differences at moderate doses (K+: p<0.01, Cl-: p<0.05) and the highest doses (both: p<0.01) of the 80% methanol extract. Furthermore, the highest doses of both the aqueous (p<0.01) and 80% methanol (p<0.01) extracts demonstrated significant differences in saluretic effect. Conclusion: Both crude extracts of C. dipsaceus leaves have significant diuretic activity, providing support for the traditional use of the plant as a diuretic agent.

Salinity-induced variations in wheat biomass are regulated by the Na+:K+ ratio, root exudates, and keystone species.

Salt stress can limit crop productivity, and there are differences in salt tolerance among plant varieties; however, we lack a comprehensive understanding of how keystone species obtained from different plant varieties under salt stress change plant biomass by driving root exudate secretion and regulating the Na+:K+ ratio. We conducted a pot experiment for three wheat varieties (JiMai32 (JM32), XiaoYan60 (XY60), and ShanRong3 (SR3)) under saline/nonsaline soil conditions. Salt stress tended to significantly reduce wheat biomass, and the biomass reduction rates of the different varieties decreased in the order JM32 < XY60 < SR3. The compositions of the bacterial and fungal communities in the root endosphere, rhizosphere and bulk soil were measured, and salt-induced microbial taxa were isolated to identify keystone species from the co-occurrence networks and to study their effects on physiological responses to salinity in wheat varieties. We observed that root exudates participated in the regulation of the Na+:K+ ratio, thereby affecting wheat biomass, and this process was regulated by keystone species. JM32 was enriched in microorganisms that promote plant growth and resistance to salt stress, such as Burkholderiales, Sordariomycetes, Alteromonadaceae, Acremonium, and Dokdonella, and inhibited microorganisms that are sensitive to the environment (salt, nutrients) and plant pathogens, such as Nocardioidaceae, Nitrospira, Cytophagaceae, Syntrophobacteriaceae, and Striaticonidium. XY60 inhibited microorganisms with biological control and disease inhibition potential, such as Agromyces and Kaistobacter. SR3-enriched pathogens, such as Aurantimonadaceae and Pseudogymnoascus, as well as microorganisms with antagonistic pathogen potential and the ability to treat bacterial infections, such as RB41 and Saccharothrix, were inhibited. Our results confirmed the crucial function of salt-induced keystone species in enhancing plant adaptation to salt stress by driving root exudate secretion and regulating the Na+:K+ ratio, with implications for exploring reasonable measures to improve plant salt tolerance.

Zinc Oxide Nanoparticles Alleviate Salt Stress in Cotton (Gossypium hirsutum L.) by Adjusting Na+/K+ Ratio and Antioxidative Ability.

Soil salinization poses a threat to the sustainability of agricultural production and has become a global issue. Cotton is an important cash crop and plays an important role in economic development. Salt stress has been harming the yield and quality of many crops, including cotton, for many years. In recent years, soil salinization has been increasing. It is crucial to study the mechanism of cotton salt tolerance and explore diversified materials and methods to alleviate the salt stress of cotton for the development of the cotton industry. Nanoparticles (NPs) are an effective means to alleviate salt stress. In this study, zinc oxide NPs (ZnO NPs) were sprayed on cotton leaves with the aim of investigating the intrinsic mechanism of NPs to alleviate salt stress in cotton. The results show that the foliar spraying of ZnO NPs significantly alleviated the negative effects of salt stress on hydroponic cotton seedlings, including the improvement of above-ground and root dry and fresh weight, leaf area, seedling height, and stem diameter. In addition, ZnO NPs can significantly improve the salt-induced oxidative stress by reducing the levels of MDA, H2O2, and O2- and increasing the activities of major antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Furthermore, RNA-seq showed that the foliar spraying of ZnO NPs could induce the expressions of CNGC, NHX2, AHA3, HAK17, and other genes, and reduce the expression of SKOR, combined with the CBL-CIPK pathway, which alleviated the toxic effect of excessive Na+ and reduced the loss of excessive K+ so that the Na+/K+ ratio was stabilized. In summary, our results indicate that the foliar application of ZnO NPs can alleviate high salt stress in cotton by adjusting the Na+/K+ ratio and regulating antioxidative ability. This provides a new strategy for alleviating the salt stress of cotton and other crops, which is conducive to the development of agriculture.

Does casual urine Na/K ratio predict 24 h urine Na/K ratio in treated hypertensive patients? Comparison between casual urine voided in the morning vs. 24 h urine collected on the previous day.

The urine sodium-to-potassium (Na/K) ratio is associated with blood pressure and cardiovascular diseases. A single urine sample is preferable for determining the Na/K ratio in clinical practice. We evaluated whether the Na/K ratio measured using morning casual urine samples predicts the ratio measured using the preceding 24 h urine sample in patients with hypertension. The study included 187 hypertensive patients (mean age 66.1 years, 52.4% female) whose Na and K concentrations were measured both in 24 h (24Na/K) and casual urine the next morning (CNa/K). The Na/K ratios were 3.54 ± 1.5 in 24NaK and 2.63 ± 1.9 in CNa/K. The two estimates showed a significant positive correlation (r = 0.49, p < 0.0001), and (CNa/K-24Na/K)/24Na/K was -23.5 ± 44.4%. In the Bland-Altman plot, the mean difference was -0.91. When CNa/K was divided into three groups, <2 (low), 2-4 (medium), and ≥4 (high), the overall agreement with 24Na/K was 46.0% (86 of 187). The low group had 24.4% agreement and 75.6% underestimation (24Na/K > CNa/K); the medium group had 60.8% agreement, 30.5% underestimation, and 8.7% overestimation (24Na/K < CNa/K); and the high group had 71.8% agreement and 28.2% overestimation. These results indicate that CNa/K and 24Na/K were significantly correlated; however, CNa/K was generally lower than 24Na/K, particularly at Na/K levels < 2. Further efforts should be made to address the validity of using casual urine Na/K ratios in hypertension management practices.

Mammary epithelium permeability during established lactation: associations with cytokine levels in human milk.

Objective: The cytokine profile of human milk may be a key indicator of mammary gland health and has been linked to infant nutrition, growth, and immune system development. The current study examines the extent to which mammary epithelium permeability (MEP) is associated with cytokine profiles during established lactation within a sample of US mothers. Methods: Participants were drawn from a previous study of human milk cytokines. The present analysis includes 162 participants (98 Black, 64 White) with infants ranging from 1 to 18 months of age. Levels of cytokines were determined previously. Here we measure milk sodium (Na) and potassium (K) levels with ion-selective probes. Two approaches were used to define elevated MEP: Na levels ≥10 mmol/L and Na/K ratios greater than 0.6. Associations between maternal-infant characteristics, elevated MEP, and twelve analytes (IL-6, IL-8, TNFα, IL-1ß, FASL, VEGFD, FLT1, bFGF, PLGF, EGF, leptin, adiponectin) were examined using bivariate associations, principal components analysis, and multivariable logistic regression models. Results: Elevated MEP was observed in 12 and 15% of milk samples as defined by Na and Na/K cutoffs, respectively. The odds of experiencing elevated MEP (defined by Na ≥ 10 mmol/L) were higher among Black participants and declined with older infant age. All cytokines, except leptin, were positively correlated with either Na or the Na/K ratio. A pro-inflammatory factor (IL-6, IL-8, TNFα, IL-1ß, EGF) and a tissue remodeling factor (FASL, VEGFD, FLT1, bFGF, PLGF, adiponectin) each contributed uniquely to raising the odds of elevated MEP as defined by either Na or the Na/K ratio. Conclusion: This exploratory analysis of MEP and cytokine levels during established lactation indicates that elevated MEP may be more common in US populations than previously appreciated and that individuals identifying as Black may have increased odds of experiencing elevated MEP based on current definitions. Research aimed at understanding the role of MEP in mammary gland health or infant growth and development should be prioritized.

Relationship between the urinary Na/K ratio, diet and hypertension among community-dwelling older adults.

The association between the urinary sodium (Na)/potassium (K) ratio and hypertension is well recognized. We investigated whether the urinary Na/K ratio might be associated with hypertension in community-dwelling older adults and whether the association was influenced by habitual dietary patterns. We enrolled a total of 684 older adults (mean age, 76.8 years) and conducted health examinations at Kusatsu, Japan, in 2021. The urinary Na/K ratio was found to be independently associated with systolic blood pressure (SBP) (p < 0.0001), years of education (p = 0.0027), number of cohabitants (p = 0.0175), estimated glomerular filtrate rate (eGFR) (p = 0.0244), and Geriatric Depression Scale short-version (GDS15) score (p = 0.0366). In addition, an unsupervised hierarchical clustering analysis revealed a spectrum of habitual dietary patterns for higher and lower values of the urinary Na/K ratio. The decision tree indicated that the urinary Na/K ratio was associated with the history of milk consumption. A positive history of daily milk consumption predicted a mean urinary Na/K ratio of 2.8, and a negative history of daily milk consumption predicted a mean urinary Na/K ratio of 3.3. Furthermore, the frequency of fruit and vegetable consumption also predicted the urinary Na/K ratio. The relationship between the urinary Na/K ratio and hypertension was influenced by the frequency of consumption of milk, fruits, and vegetables in the subjects. This finding might be due to the influence of education and/or depression. The results suggested the importance of nutritional education in the development of hypertension.

Enhancing growth and salinity stress tolerance of date palm using Piriformospora indica.

Endophytic fungi are known to enhance plant growth and performance under salt stress. The current study investigated the growth, as well as biochemical and molecular properties of Phoenix dactylifera colonized with the mutualistic fungus Piriformospora indica, under control and salinity stress. Our findings indicated an increase in the plant biomass, lateral root density, and chlorophyll content of P. indica-colonized plants under both normal and salt stress conditions. Furthermore, there was a decline in the inoculated plants leaf and root Na+/K+ ratio. The colonization enhanced the levels of antioxidant enzymes such as catalase, superoxide dismutase, and peroxidase in plants. Increased ionic content of Zn and P were also found in salt-stressed date palm. The fungus colonization was also associated with altered expression levels of essential Na+ and K+ ion channels in roots like HKT1;5 and SOS1 genes. This alteration improved plant growth due to their preservation of Na+ and K+ ions balanced homeostasis under salinity stress. Moreover, it was confirmed that RSA1 and LEA2 genes were highly expressed in salt-stressed and colonized plant roots and leaves, respectively. The current study exploited P. indica as an effective natural salt stress modulator to ameliorate salinity tolerance in plants.

Targeting the Dietary Na:K Ratio-Considerations for Design of an Intervention Study to Impact Blood Pressure.

Despite medical, dietary, and lifestyle recommendations and drug advancements, hypertension persists as among the most prevalent noncommunicable diseases in the US population, and control remains elusive. Uncontrolled hypertension may increase the risk of serious illness from various other health challenges, including cardiovascular and renal responses. Adoption of a healthy diet is a consistent core element of lifestyle modifications that are recommended for mitigation of hypertension. The dietary sodium-to-potassium ratio is recognized as having promising potential in the regulation of blood pressure. In fact, the understanding of the relation between this ratio and blood pressure was documented as a key evidence gap in the 2019 National Academies of Sciences, Engineering, and Medicine report that revised recommended intake levels for both sodium and potassium. Although notable animal and human evidence supports this point, fundamental to developing a specific dietary recommendation for a sodium-to-potassium ratio is a well-designed human intervention trial. The successful translatability of such a trial will require careful consideration of study elements, including the study population, duration, blood pressure measurement, and dietary intervention, among other factors. This paper addresses these decision points and serves as supporting documentation for a research group or organization with the interest and means to address this important data gap, which will undoubtedly be foundational for advancing dietary guidance and would inform the next iteration of Dietary Reference Intakes for sodium and potassium.

Consideration of the reference value and number of measurements of the urinary sodium-to-potassium ratio based on the prevalence of untreated home hypertension: TMM Cohort Study.

The sodium-to-potassium (Na/K) ratio is known to be associated with blood pressure (BP). However, no reference value has been established since the urinary Na/K (uNa/K) ratio is known to have diurnal and day-to-day variations. Therefore, we investigated the number of days required to yield a better association between the morning uNa/K ratio and home BP (HBP) and determined a morning uNa/K ratio value that can be used as a reference value in participants who are not taking antihypertensive medication. This was a cross-sectional study using data from the Tohoku Medical Megabank Project Cohort Study. A total of 3122 participants borrowed HBP and uNa/K ratio monitors for 10 consecutive days. We assessed the relationship between the morning uNa/K ratio from 1 day to 10 days and home hypertension (HBP ≥ 135/85 mmHg) using multiple logistic regression models. Although a 1-day measurement of the morning uNa/K ratio was positively associated with home hypertension, multiple measurements of the morning uNa/K ratio were strongly related to home hypertension. The average morning uNa/K ratio was relatively stable after 3 days (adjusted odds ratio of home hypertension per unit increase in the uNa/K ratio for more than 3 days: 1.19-1.23). In conclusion, there was no threshold for the uNa/K ratio, and the morning uNa/K ratio was linearly associated with home hypertension. The Na/K ratio 2.0 calculated from the Dietary Reference Intakes for Japanese might be a good indication. Regarding the stability of the association between the morning uNa/K ratio and BP, more than 3 days of measurements is desirable.

Zn alleviated salt toxicity in Solanum lycopersicum L. seedlings by reducing Na+ transfer, improving gas exchange, defense system and Zn contents.

Soil secondary salinization is a serious menace that has significant influence on the sustainability of agriculture and threatens food security around the world. Zinc (Zn) as an essential plant nutrient associated with many physio-biochemical processes in plants and improve resistance against various abiotic stresses. The role of Zn in acclimation of Solanum lycopersicum L. challenged with salt stress is miserly understood. A hydroponic study was performed with two tomato varieties (Riogrande and Sungold) exposed to the salinity stress (0 mM and 160 mM NaCl) under two Zn concentrations (15 µM and 30 µM ZnSO4). The results revealed that salt stress exerted strongly negative impacts on root and shoot length, fresh and dry biomass, plant water relations, membrane stability, chlorophyll contents, Na+/K+ ratio along with inferior gas exchange attributes and activities of antioxidant enzymes. Moreover, Riogrande was found to be more resistant to salinity stress than Sungold. However, Zn supply significantly alleviated the hazardous effects of salinity by altering compatible solutes accumulation, photosynthetic activity, water relation, soluble sugar contents and providing antioxidant defense against salt stress. The salinity + Zn2 treatment more obviously enhanced RWC (19.0%), MSI (30.8%), SPAD value (17.8%), and activities of SOD (31.7%), POD (28.5%), APX (64.5%) and CAT (23.3%) in Riogrande than Sungold, compared with the corresponding salinity treatment alone. In addition, salinity + Zn2 treatment significantly (P > 0.05) ameliorated salinity stress due to the depreciation in Na+/K+ ratio by 63.3% and 40.8%, Na+ ion relocation from root to shoot by 10.4% and 6.4%, and thereby significantly reduced Na+ ion accumulation by 47.4% and 16.3% in the leaves of Riogrande and Sungold respectively, compared to the salinity treatment alone. Therefore, it was obvious that 30 µM Zn concentration was more effective to induce resistance against salinity stress than 15 µM Zn concentration. Conclusively, it can be reported that exogenous Zn application helps tomato plant to combat adverse saline conditions by modulating photosynthetic and antioxidant capacity along with reduced Na+ uptake at the root surface of tomato plant.

Genetic Dissection of Alkalinity Tolerance at the Seedling Stage in Rice (Oryza sativa) Using a High-Resolution Linkage Map.

Although both salinity and alkalinity result from accumulation of soluble salts in soil, high pH and ionic imbalance make alkaline stress more harmful to plants. This study aimed to provide molecular insights into the alkalinity tolerance using a recombinant inbred line (RIL) population developed from a cross between Cocodrie and Dular with contrasting response to alkalinity stress. Forty-six additive QTLs for nine morpho-physiological traits were mapped on to a linkage map of 4679 SNPs under alkalinity stress at the seedling stage and seven major-effect QTLs were for alkalinity tolerance scoring, Na+ and K+ concentrations and Na+:K+ ratio. The candidate genes were identified based on the comparison of the impacts of variants of genes present in five QTL intervals using the whole genome sequences of both parents. Differential expression of no apical meristem protein, cysteine protease precursor, retrotransposon protein, OsWAK28, MYB transcription factor, protein kinase, ubiquitin-carboxyl protein, and NAD binding protein genes in parents indicated their role in response to alkali stress. Our study suggests that the genetic basis of tolerance to alkalinity stress is most likely different from that of salinity stress. Introgression and validation of the QTLs and genes can be useful for improving alkalinity tolerance in rice at the seedling stage and advancing understanding of the molecular genetic basis of alkalinity stress adaptation.

Pan-cerebral sodium elevations in vascular dementia: Evidence for disturbed brain-sodium homeostasis.

Vascular dementia (VaD) is the second most common cause of cognitive impairment amongst the elderly. However, there are no known disease-modifying therapies for VaD, probably due to incomplete understanding of the molecular basis of the disease. Despite the complex etiology of neurodegenerative conditions, a growing body of research now suggests the potential involvement of metal dyshomeostasis in the pathogenesis of several of the age-related dementias. However, by comparison, there remains little research investigating brain metal levels in VaD. In order to shed light on the possible involvement of metal dyshomeostasis in VaD, we employed inductively coupled plasma-mass spectrometry to quantify the levels of essential metals in post-mortem VaD brain tissue (n = 10) and age-/sex-matched controls (n = 10) from seven brain regions. We found novel evidence for elevated wet-weight cerebral sodium levels in VaD brain tissue in six out of the seven regions analyzed. Decreased cerebral-potassium levels as well as increased Na/K ratios (consistent with high tissue sodium and low potassium levels) were also observed in several brain regions. These data suggest that reduced Na+/K+-exchanging ATPase (EC 7.2.2.13) activity could contribute to the contrasting changes in sodium and potassium measured here.