-
The New Phytologist Sep 2022Chenopodium quinoa uses epidermal bladder cells (EBCs) to sequester excess salt. Each EBC complex consists of a leaf epidermal cell, a stalk cell, and the bladder. Under...
Chenopodium quinoa uses epidermal bladder cells (EBCs) to sequester excess salt. Each EBC complex consists of a leaf epidermal cell, a stalk cell, and the bladder. Under salt stress, sodium (Na ), chloride (Cl ), potassium (K ) and various metabolites are shuttled from the leaf lamina to the bladders. Stalk cells operate as both a selectivity filter and a flux controller. In line with the nature of a transfer cell, advanced transmission electron tomography, electrophysiology, and fluorescent tracer flux studies revealed the stalk cell's polar organization and bladder-directed solute flow. RNA sequencing and cluster analysis revealed the gene expression profiles of the stalk cells. Among the stalk cell enriched genes, ion channels and carriers as well as sugar transporters were most pronounced. Based on their electrophysiological fingerprint and thermodynamic considerations, a model for stalk cell transcellular transport was derived.
Topics: Chenopodium quinoa; Ion Transport; Ions; Potassium; Salinity; Salt Tolerance; Salt-Tolerant Plants; Sodium; Urinary Bladder
PubMed: 35510810
DOI: 10.1111/nph.18205 -
Scientific Reports Nov 2023Multiple electrolyte disorders, including sodium, potassium and calcium disorders, have been associated with hypertension in pregnancy. Most of these studies failed to...
Multiple electrolyte disorders, including sodium, potassium and calcium disorders, have been associated with hypertension in pregnancy. Most of these studies failed to evaluate the combined effect of low and high sodium, potassium, calcium and chloride ion concentrations on hypertension in pregnancy. This study evaluates the combined effect of these ion categories (low, normal, high) on hypertension in pregnancy. Biochemical ion assays and blood pressure measurements were carried out on 1074 apparently healthy pregnant women in late third trimester. Serum potassium, sodium, chloride, and ionised calcium were measured by ion-selective electrode potentiometry, while total plasma calcium was measured by absorption spectrophotometry. Hypertension in pregnancy was defined as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg. The prevalence of hyponatraemia, hypokalaemia, hypochloraemia, ionised hypocalcaemia and total hypocalcaemia in late pregnancy was 1.30 [0.78-2.18]%, 3.55 [2.60-4.84]%, 1.96 [1.28-2.97]%, 1.49 [0.92-2.21]% and 43.58 [40.64-46.56]%, respectively. Hypernatraemia, hyperkalaemia, hyperchloraemia, ionised hypercalcaemia and total hypercalcaemia were found in 1.49 [0.92-2.41]%, 2.34 [1.59-3.43]%, 4.38 [3.31-5.77]%, 39.94 [37.06-42.90]%, 2.79 [1.96-3.96]% of the participants, respectively. The prevalence of hypertension in pregnancy was 7.17 [5.77-8.87]%. When ion categories were considered in multiple logistic regression, only ionised and total calcium had significant associations with hypertension in pregnancy. Women with ionised hypercalcaemia had lower odds of hypertension in pregnancy (AOR = 0.50 [0.29-0.87], p-value = 0.015), and women with total hypocalcaemia had higher odds of hypertension in pregnancy (AOR = 1.99 [1.21-3.29], p-value = 0.007), compared to women with ionised and total normocalcaemia, respectively. Increasing kalaemia was associated significantly with higher odds of hypertension in pregnancy; however, kalaemia below and above the normal concentrations had no significant association with hypertension. Nonetheless, participants with kalaemia ≤ 3.98 mmol/L, had lower odds of hypertension in pregnancy compared with those with higher kalaemia (OR = 0.40 [0.24-0.66], p-value = 0.0003). Calcium disorders remain the most frequent electrolyte disorders in pregnancy. When normal cut-offs are considered for calcium and other ions, only ionised and total calcium influence the occurrence of hypertension in pregnancy. Kalaemia seems to affect hypertension in pregnancy but primarily within its normal concentrations. Serum electrolyte follow-up is indispensable for a proper pregnancy follow-up.
Topics: Humans; Female; Pregnancy; Calcium; Hypercalcemia; Hypocalcemia; Cameroon; Chlorides; Electrolytes; Hypertension; Sodium; Potassium; Calcium, Dietary
PubMed: 38017060
DOI: 10.1038/s41598-023-47623-6 -
Environmental Science and Pollution... Oct 2023Members of the Gulf Cooperation Council countries Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates rely on desalination to produce water for...
Members of the Gulf Cooperation Council countries Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates rely on desalination to produce water for domestic use. Desalination produces brine that may intrude into the aquifers to pollute the fresh groundwater because of the concentration gradient and groundwater pumping. Modeling the trends of saltwater intrusion needs theoretical understanding and thorough logical experimentation. The objective of this exercise was to understand the phenomenon of saltwater intrusion using an existing set of data analyzed with the convective-diffusion equation and the two-region mobile-immobile solution model. The objective was achieved by optimizing non-measurable solute transport parameters from an existing set of data generated from a series of logical miscible displacements of potassium bromide through sepiolite minerals and curve-fitting simulations. Assumptions included that solute displacements through sepiolite porous media and the related simulations represented the phenomenon of saltwater intrusion under non-equilibrium conditions of porous media mimicking the aquifers. Miscible displacements of potassium bromide were observed from a column of 2.0-2.8 mm aggregates of sepiolite over 4 ranges of concentration and at 11 displacement speeds under saturated vertical flow deionized water and vice versa. Breakthrough curves of both bromide and potassium ions were analyzed by a curve-fitting technique to optimize transport parameters assuming solute movement was governed (i) by the convective-diffusion equation and (ii) the two-region mobile-immobile solution model. Column Peclet numbers from the two analyses were identical for potassium ions but those for bromide ions were c. 60% greater from the two-region model than from the convective-diffusion equation. For the two-region model, dispersion coefficients were well defined and remained unchanged from the convective-diffusion equation for potassium ions but decreased for bromide ions. Retardation factors for bromide ions were approximately the same, but those for potassium ions, though > 1, were poorly defined. In order to design mitigation strategies for avoiding groundwater contamination, this study's findings may help model groundwater pollution caused by the activities of desalination of seawater, which produces concentrated liquid that intrudes into the coastal aquifer through miscible displacement. However, robust saltwater intrusion models may be considered in future studies to confirm the results of the approach presented in this exercise. Field data on the groundwater contamination levels may be collected to compare with simulated trends drawn from the saltwater intrusion models and the curve-fitting technique used in this work. A comparison of the output from the two types of models may help determine the right option to understand the phenomena of saltwater intrusion into coastal aquifers of various characteristics.
Topics: Bromides; Groundwater; Water; Seawater; Ions; Potassium; Environmental Monitoring
PubMed: 37759059
DOI: 10.1007/s11356-023-29866-y -
PLoS Biology Sep 2022Potassium ion (K+) plays a critical role as an essential electrolyte in all biological systems. Genetically-encoded fluorescent K+ biosensors are promising tools to...
Potassium ion (K+) plays a critical role as an essential electrolyte in all biological systems. Genetically-encoded fluorescent K+ biosensors are promising tools to further improve our understanding of K+-dependent processes under normal and pathological conditions. Here, we report the crystal structure of a previously reported genetically-encoded fluorescent K+ biosensor, GINKO1, in the K+-bound state. Using structure-guided optimization and directed evolution, we have engineered an improved K+ biosensor, designated GINKO2, with higher sensitivity and specificity. We have demonstrated the utility of GINKO2 for in vivo detection and imaging of K+ dynamics in multiple model organisms, including bacteria, plants, and mice.
Topics: Animals; Biosensing Techniques; Fluorescence Resonance Energy Transfer; Ions; Mice; Potassium
PubMed: 36067248
DOI: 10.1371/journal.pbio.3001772 -
American Journal of Physiology. Cell... Apr 2022Inflammation is part of innate immunity and is a natural response of the body to bacteria, virus, and any other pathogen infections or to damaged tissues. However, too... (Review)
Review
Inflammation is part of innate immunity and is a natural response of the body to bacteria, virus, and any other pathogen infections or to damaged tissues. However, too much inflammation or chronic inflammation contributes to a wide variety of diseases such as inflammatory bowel disease, cancer, type 2 diabetes, heart disease, and autoimmune diseases such as rheumatoid arthritis. Recent studies underscored the critical role of K and Cl efflux in the activation of the inflammasome. The NLRP3 inflammasome is a multiprotein complex that mediates the production of the proinflammatory cytokines IL-1β and IL-18 and initiates the inflammatory cell death or pyroptosis. The NLRP3 inflammasome can be activated by multiple stimuli such as extracellular ATP, microbial toxins, ROS, mitochondrial DNA, or particulate matter. Although the precise mechanisms of NLRP3 activation and regulation by these diverse agonists remain unclear, multiple reports indicate that all NLRP3 agonists ultimately lead to a drop in intracellular concentration of potassium (K efflux) and chloride (Cl efflux). The WNK-SPAK/OSR1-[N]KCC pathway plays a critical role in maintaining K and Cl ion concentrations in the cell. Recent advances indicate that the WNK-SPAK-[N]KCC pathway plays a role in the activation of the innate immune response. This review highlights recent discoveries detailing how ion transport regulates innate immune cell response to inflammatory stimuli.
Topics: Chlorides; Diabetes Mellitus, Type 2; Humans; Immunity, Innate; Inflammasomes; Inflammation; Interleukin-1beta; NLR Family, Pyrin Domain-Containing 3 Protein; Potassium
PubMed: 35171697
DOI: 10.1152/ajpcell.00421.2021 -
American Journal of Physiology. Renal... Mar 2023The Cl/[Formula: see text] exchanger pendrin in the kidney maintains acid-base balance and intravascular volume. Pendrin is upregulated in models associated with high...
The Cl/[Formula: see text] exchanger pendrin in the kidney maintains acid-base balance and intravascular volume. Pendrin is upregulated in models associated with high circulating aldosterone concentration, such as dietary NaCl restriction or an aldosterone infusion. However, it has not been established if pendrin is similarly regulated by aldosterone with a high-K diet because the effects of accompanying anions have not been considered. Here, we explored how pendrin is modulated by different dietary potassium salts. Wild-type (WT) and aldosterone synthase (AS) knockout (KO) mice were randomized to control, high-KHCO, or high-KCl diets. Dietary KCl and KHCO loading increased aldosterone in WT mice to the same extent but had opposite effects on pendrin abundance. KHCO loading increased pendrin protein and transcript abundance. Conversely, high-KCl diet feeding caused pendrin to decrease within 8 h of switching from the high-KHCO diet, coincident with an increase in plasma Cl and a decrease in [Formula: see text]. In contrast, switching the high-KCl diet to the high-KHCO diet caused pendrin to increase in WT mice. Experiments in AS KO mice revealed that aldosterone is necessary to optimally upregulate pendrin protein in response to the high-KHCO diet but not to increase pendrin mRNA. We conclude that pendrin is differentially regulated by different dietary potassium salts and that its regulation is prioritized by the dietary anion, providing a mechanism to prevent metabolic alkalosis with high-K base diets and safeguard against hyperchloremic acidosis with consumption of high-KCl diets. Regulation of the Cl/[Formula: see text] exchanger pendrin has been suggested to explain the aldosterone paradox. A high-K diet has been proposed to downregulate a pendrin-mediated K-sparing NaCl reabsorption pathway to maximize urinary K excretion. Here, we challenged the hypothesis, revealing that the accompanying anion, not K, drives pendrin expression. Pendrin is downregulated with a high-KCl diet, preventing acidosis, and upregulated with an alkaline-rich high-K diet, preventing metabolic alkalosis. Pendrin regulation is prioritized for acid-base balance.
Topics: Animals; Mice; Acidosis; Aldosterone; Alkalosis; Anion Transport Proteins; Bicarbonates; Diet; Potassium; Potassium, Dietary; Salts; Sodium Chloride; Sulfate Transporters
PubMed: 36656986
DOI: 10.1152/ajprenal.00128.2022 -
Current Protocols in Chemical Biology Sep 2019Vital cells maintain a steep potassium ion (K ) gradient across the plasma membrane. Intracellular potassium ion concentrations ([K ]) and especially the [K ] within the...
Vital cells maintain a steep potassium ion (K ) gradient across the plasma membrane. Intracellular potassium ion concentrations ([K ]) and especially the [K ] within the extracellular matrix are strictly regulated, the latter within a narrow range of ∼3.5 to 5.0 mM. Alterations of the extracellular K homeostasis are associated with severe pathological alterations and systemic diseases including hypo- or hypertension, heart rate alterations, heart failure, neuronal damage or abnormal skeleton muscle function. In higher eukaryotic organisms, the maintenance of the extracellular [K ] is mainly achieved by the kidney, responsible for K excretion and reabsorption. Thus, renal dysfunctions are typically associated with alterations in serum- or plasma [K ]. Generally, [K ] quantifications within bodily fluids are performed using ion selective electrodes. However, tracking such alterations in experimental models such as mice features several difficulties, mainly due to the small blood volume of these animals, hampering the repetitive collection of sample volumes required for measurements using ion selective electrodes. We have recently developed highly sensitive, genetically encoded potassium ion indicators, the GEPIIs, applicable for in vitro determinations of [K ]. In addition to the determination of [K ] within bodily fluids, GEPIIs proved suitable for the real-time visualization of cell viability over time and the exact determination of the number of dead cells. © 2019 The Authors.
Topics: Animals; Body Fluids; Cell Line, Tumor; Cell Survival; Fluorescence Resonance Energy Transfer; Glucose; Ions; Mice; Plasmids; Potassium; Recombinant Proteins
PubMed: 31483097
DOI: 10.1002/cpch.71 -
BMC Plant Biology Jul 2019HKT channels mediate sodium uniport or sodium and potassium symport in plants. Monocotyledons express a higher number of HKT proteins than dicotyledons, and it is only...
BACKGROUND
HKT channels mediate sodium uniport or sodium and potassium symport in plants. Monocotyledons express a higher number of HKT proteins than dicotyledons, and it is only within this clade of HKT channels that cation symport mechanisms are found. The prevailing ion composition in the extracellular medium affects the transport abilities of various HKT channels by changing their selectivity or ion transport rates. How this mutual effect is achieved at the molecular level is still unknown. Here, we built a homology model of the monocotyledonous OsHKT2;2, which shows sodium and potassium symport activity. We performed molecular dynamics simulations in the presence of sodium and potassium ions to investigate the mutual effect of cation species.
RESULTS
By analyzing ion-protein interactions, we identified a cation coordination site on the extracellular protein surface, which is formed by residues P71, D75, D501 and K504. Proline and the two aspartate residues coordinate cations, while K504 forms salt bridges with D75 and D501 and may be involved in the forwarding of cations towards the pore entrance. Functional validation via electrophysiological experiments confirmed the biological relevance of the predicted ion coordination site and identified K504 as a central key residue. Mutation of the cation coordinating residues affected the functionality of HKT only slightly. Additional in silico mutants and simulations of K504 supported experimental results.
CONCLUSION
We identified an extracellular cation coordination site, which is involved in ion coordination and influences the conduction of OsHKT2;2. This finding proposes a new viewpoint in the discussion of how the mutual effect of variable ion species may be achieved in HKT channels.
Topics: Animals; Cation Transport Proteins; Cations; Cloning, Molecular; Electrophysiology; Ion Transport; Mutation; Plant Proteins; Potassium; Protein Conformation; Sodium; Structure-Activity Relationship; Xenopus laevis
PubMed: 31307394
DOI: 10.1186/s12870-019-1909-5 -
Experimental and Clinical... Mar 2022Calcineurin inhibitors are the cornerstone of immunosuppression following solid-organ transplant. However, hyperkalemia may occur by multiple mechanisms affecting...
OBJECTIVES
Calcineurin inhibitors are the cornerstone of immunosuppression following solid-organ transplant. However, hyperkalemia may occur by multiple mechanisms affecting potassium in the distal tubule. Hyperkalemia is commonly observed in renal transplant recipients, and it is dose-dependent. Here, we evaluated the impact of fludrocortisone in the management of calcineurin inhibitor-induced hyperkalemia after renal transplant.
MATERIALS AND METHODS
We evaluated newly transplanted patients who developed hyperkalemia or those with hyperkalemia who attended our outpatient renal transplant clinic (Hamed Al-Essa Organ Transplant Center, Kuwait). Clinical and laboratory parameters were collected before starting fludrocortisone (baseline values) and then at 1, 2, 4, and 8 weeks. Drug history was assessed, with any drugs that could induce hyperkalemia being discontinued (such as spironolactone); otherwise, essential drugs like prophylactic agents (sulfamethoxazole-trimethoprim) were maintained. Oral anti-hyperkalemic doses (bicarbonate, resonium calcium, fludrocortisone) were noted.
RESULTS
Our study included 29 patients; most were men (aged 45.8 ± 15 years). Body weight did not significantly change after introduction of fludrocortisone (79.53 ± 24.31, 79.82 ± 23.85, 80.62 ± 24.24, 77.03 ± 20.7, and 79.21 ± 27.93 kg at baseline and at postdose week 1, 2, 4, and 8, respectively). Systolic and diastolic blood pressure levels were also similar at baseline versus postdose. Steroid doses (prednisolone) were significantly reduced over 1 month (15.7 ± 12.4, 14.1 ± 10.19, 12.6 ± 8.7, 9.5 ± 5.2, and 9.5 ± 5.2 mg/ day). Serum potassium levels significantly improved (5.18 ± 0.58, 4.9 ± 0.49, 4.8 ± 0.54, 4.8 ± 0.65, and 4.4 ± 0.72 mmol/L). Serum creatinine levels significantly improved by postdose week 8 (129.28 ± 48.9, 130.92 ± 52.2, 127.66 ± 50.9, 121.42 ± 41.7, and 124.1 ± 51.27 μmol/L). Serum bicarbonate levels remained similar.
CONCLUSIONS
Fludrocortisone was a safe and effective option in management of calcineurin inhibitor-induced hyperkalemia among renal transplant recipients.
Topics: Adult; Bicarbonates; Calcineurin Inhibitors; Fludrocortisone; Humans; Hyperkalemia; Kidney Transplantation; Male; Middle Aged; Potassium; Treatment Outcome
PubMed: 35384810
DOI: 10.6002/ect.MESOT2021.O27 -
Biochemia Medica Jun 2022Blood gas analysis (BGA) is an essential test used for years to provide vital information in critically ill patients. However, the instability of the blood gases is a...
INTRODUCTION
Blood gas analysis (BGA) is an essential test used for years to provide vital information in critically ill patients. However, the instability of the blood gases is a problem. We aimed to evaluate time and temperature effects on blood gas stability.
MATERIALS AND METHODS
Arterial blood was collected from 20 patients into syringes. Following BGA for baseline, syringes were divided into groups to stand at 4°C and 22°C for 30, 60, 90, 120 minutes. All were tested for pH, partial pressure of carbon dioxide (pCO), partial pressure of oxygen (pO), oxygen saturation (sO), oxyhemoglobin (OHb), sodium, potassium, glucose, lactate, oxygen tension at 50% hemoglobin saturation (p50), and bicarbonate. A subgroup analysis was performed to detect the effect of air on results during storage. Percentage deviations were calculated and compared against the preset quality specifications for allowable total error.
RESULTS
At 4°C, pO was the least stable parameter. At 22°C, pO remained stable for 120 min, pH and glucose for 90 min, lactate and pCO for 60 min. Glucose and lactate were stable when chilled. Air bubbles interfered pO regardless of temperatures, whereas pCO increased significantly at 22°C after 30 min, and pH decreased after 90 min. Bicarbonate, sO, OHb, sodium, and potassium were the unaffected parameters.
CONCLUSIONS
Correct BGA results are essential, and arterial sample is precious. Therefore, if immediate analysis cannot be performed, up to one hour, syringes stored at room temperature will give reliable results when care is taken to minimize air within the blood gas specimen.
Topics: Bicarbonates; Blood Gas Analysis; Glucose; Humans; Hydrogen-Ion Concentration; Lactates; Oxygen; Potassium; Sodium
PubMed: 35799987
DOI: 10.11613/BM.2022.020708