ER-to-lysosome Ca2+ refilling followed by K+ efflux-coupled store-operated Ca2+ entry in inflammasome activation and metabolic inflammation.

We studied lysosomal Ca2+ in inflammasome. Lipopolysaccharide (LPS) + palmitic acid (PA) decreased lysosomal Ca2+ ([Ca2+]Lys) and increased [Ca2+]i through mitochondrial ROS, which was suppressed in Trpm2-KO macrophages. Inflammasome activation and metabolic inflammation in adipose tissue of high-fat diet (HFD)-fed mice were ameliorated by Trpm2 KO. ER→lysosome Ca2+ refilling occurred after lysosomal Ca2+ release whose blockade attenuated LPS + PA-induced inflammasome. Subsequently, store-operated Ca2+entry (SOCE) was activated whose inhibition suppressed inflammasome. SOCE was coupled with K+ efflux whose inhibition reduced ER Ca2+ content ([Ca2+]ER) and impaired [Ca2+]Lys recovery. LPS + PA activated KCa3.1 channel, a Ca2+-activated K+ channel. Inhibitors of KCa3.1 channel or Kcnn4 KO reduced [Ca2+]ER, attenuated increase of [Ca2+]i or inflammasome activation by LPS + PA, and ameliorated HFD-induced inflammasome or metabolic inflammation. Lysosomal Ca2+ release induced delayed JNK and ASC phosphorylation through CAMKII-ASK1. These results suggest a novel role of lysosomal Ca2+ release sustained by ER→lysosome Ca2+ refilling and K+ efflux through KCa3.1 channel in inflammasome activation and metabolic inflammation.

Isotopologues of potassium 2,2,2-trifluoroethoxide for applications in positron emission tomography and beyond.

The 2,2,2-trifluoroethoxy group increasingly features in drugs and potential tracers for biomedical imaging with positron emission tomography (PET). Herein, we describe a rapid and transition metal-free conversion of fluoroform with paraformaldehyde into highly reactive potassium 2,2,2-trifluoroethoxide (CF3CH2OK) and demonstrate robust applications of this synthon in one-pot, two-stage 2,2,2-trifluoroethoxylations of both aromatic and aliphatic precursors. Moreover, we show that these transformations translate easily to fluoroform that has been labeled with either carbon-11 (t1/2 = 20.4 min) or fluorine-18 (t1/2 = 109.8 min), so allowing the appendage of complex molecules with a no-carrier-added 11C- or 18F- 2,2,2-trifluoroethoxy group. This provides scope to create candidate PET tracers with radioactive and metabolically stable 2,2,2-trifluoroethoxy moieties. We also exemplify syntheses of isotopologues of potassium 2,2,2-trifluoroethoxide and show their utility for stable isotopic labeling which can be of further benefit for drug discovery and development.

Control of cyanobacterial growth with potassium; implications for bloom control in nuclear storage ponds.

Microbial blooms have been reported in the First Generation Magnox Storage Pond at the Sellafield Nuclear Facility. The pond is kept alkaline with NaOH to minimise fuel rod corrosion, however alkali-tolerant microbial blooms dominated by the cyanobacterium Pseudanabaena catenata are able to thrive in this hostile environment. This study assessed the impact of alternative alkali-dosing regimens (KOH versus NaOH treatment) on biomass accumulation, using a P. catenata dominated mixed culture, which is representative of the pond environment. Optical density was reduced by 40-67 % with KOH treatment over the 3-month chemostat experiment. Microbial community analysis and proteomics demonstrated that the KOH-dependent inhibition of cell growth was mostly specific to P. catenata. The addition of KOH to nuclear storage ponds may therefore help control growth of this pioneer photosynthetic organism due to its sensitivity to potassium, while maintaining the high pH needed to inhibit the corrosion of stored nuclear fuel.

The Antimicrobial Activity of Human Defensins at Physiological Non-Permeabilizing Concentrations Is Caused by the Inhibition of the Plasma Membrane H+-ATPases.

Human defensins are cysteine-rich peptides (Cys-rich peptides) of the innate immune system. Defensins contain an ancestral structural motif (i.e., γ-core motif) associated with the antimicrobial activity of natural Cys-rich peptides. In this study, low concentrations of human α- and ß-defensins showed microbicidal activity that was not associated with cell membrane permeabilization. The cell death pathway was similar to that previously described for human lactoferrin, also an immunoprotein containing a γ-core motif. The common features were (1) cell death not related to plasma membrane (PM) disruption, (2) the inhibition of microbicidal activity via extracellular potassium, (3) the influence of cellular respiration on microbicidal activity, and (4) the influence of intracellular pH on bactericidal activity. In addition, in yeast, we also observed (1) partial K+-efflux mediated via Tok1p K+-channels, (2) the essential role of mitochondrial ATP synthase in cell death, (3) the increment of intracellular ATP, (4) plasma membrane depolarization, and (5) the inhibition of external acidification mediated via PM Pma1p H+-ATPase. Similar features were also observed with BM2, an antifungal peptide that inhibits Pma1p H+-ATPase, showing that the above coincident characteristics were a consequence of PM H+-ATPase inhibition. These findings suggest, for the first time, that human defensins inhibit PM H+-ATPases at physiological concentrations, and that the subsequent cytosolic acidification is responsible for the in vitro microbicidal activity. This mechanism of action is shared with human lactoferrin and probably other antimicrobial peptides containing γ-core motifs.

Stepwise extraction of lithium and potassium and recovery of fluoride from aluminum electrolyte wastes through calcification roasting-two-stage leaching.

Aluminum electrolyte is a necessity for aluminum reduction cells; however, its stock is rising every year due to several factors, resulting in the accumulation of solid waste. Currently, it has become a favorable material for the resources of lithium, potassium, and fluoride. In this study, the calcification roasting-two-stage leaching process was introduced to extract lithium and potassium separately from aluminum electrolyte wastes, and the fluoride in the form of CaF2 was recycled. The separation behaviors of lithium and potassium under different conditions were investigated systematically. XRD and SEM-EDS were used to elucidate the phase evolution of the whole process. During calcification roasting-water leaching, the extraction efficiency of potassium was 98.7% under the most suitable roasting parameters, at which the lithium extraction efficiency was 6.6%. The mechanism analysis indicates that CaO combines with fluoride to form CaF2, while Li-containing and K-containing fluorides were transformed into water-insoluble LiAlO2 phase and water-soluble KAlO2 phase, respectively, thereby achieving the separation of two elements by water leaching. In the second acid-leaching stage, the extraction efficiency of lithium was 98.8% from water-leached residue under the most suitable leaching conditions, and CaF2 was obtained with a purity of 98.1%. The present process can provide an environmentally friendly and promising method to recycle aluminum electrolyte wastes and achieve resource utilization.

Home blood pressure measurement days and changes in urinary sodium-to-potassium ratio, estimated salt and potassium intakes and blood pressure: 1-year prospective study.

OBJECTIVE: Current international guidelines recommend home blood pressure (BP) measurement and low sodium and high potassium intakes for the management of hypertension. We hypothesized that increased home BP measurement may result in more effective management of sodium and potassium intakes and BP. METHODS: We examined associations of home BP measurement days with changes in the urinary sodium-to-potassium (Na/K) ratio, estimated salt and potassium intakes and BP. We included 209 healthy participants (mean age, 55.9 years; 56.5% women) from a prospective cohort study. We examined 1-year data on self-measured home BP and spot urine samples. RESULTS: Median (interquartile range) days of home BP measurement was 324 (225-358) over 1-year. Baseline mean (SD) Na/K ratio, salt and potassium intakes, morning and evening SBP, and morning and evening DBP were 3.8 (2.3), 8.5 (1.9) g/day, 1833.5 (416.5) mg/day, 120.4 (14.0) mmHg, 118.2 (14.2) mmHg, 79.2 (10.1) mmHg, and 76.2 (10.1) mmHg, respectively. In multivariable-adjusted linear regression , ß (standard error) per 10 days increase in number of home BP measurement were -0.031 (0.017) for Na/K ratio, -0.036 (0.015) for salt intake, -1.357 (2.797) for potassium intake, -0.178 (0.064) for morning SBP, -0.079 (0.041) for morning DBP, -0.109 (0.067) for evening SBP and -0.099 (0.045) for evening DBP. Additionally, relationships persisted for men and women, but changes in salt intake were more pronounced among participants taking antihypertensive medication (interaction P = 0.002). CONCLUSION: Continuous measurement of home BP may lead not only to self-monitoring of BP, but also to declines in salt intakes and some BP indices.

Systemic immune-inflammation index and serum glucose-potassium ratio predict poor prognosis in patients with spontaneous cerebral hemorrhage: An observational study.

Recent studies have shown systemic inflammatory response, serum glucose, and serum potassium are associated with poor prognosis in spontaneous intracerebral hemorrhage (SICH). This retrospective study aimed to investigate the association of systemic immune-inflammatory index (SII) and serum glucose-potassium ratio (GPR) with the severity of disease and the poor prognosis of patients with SICH at 3 months after hospital discharge. We reviewed the clinical data of 105 patients with SICH, assessed the extent of their disease using Glasgow Coma Scale score, National Institutes of Health Stroke Scale (NIHSS) score, and hematoma volume, and categorized them into a good prognosis group (0-3 scores) and a poor prognosis group (4-6 scores) based on their mRS scores at 3 months after hospital discharge. Demographic characteristics, clinical, laboratory, and imaging data at admission were compared between the 2 groups, bivariate correlations were analyzed using Spearman's correlation coefficients, multivariate logistic regression analysis was used to determine the independent risk factors for poor prognosis of patients with SICH, and finally, SII, GPR, and platelet/lymphocyte ratio (PLR) were examined using the subject's work characteristics (ROC) curve, lymphocyte/monocyte ratio (LMR), and neutrophil/lymphocyte ratio (NLR) for their predictive efficacy for poor prognosis. Patients in the poor prognosis group had significantly higher SII and serum GPR than those in the good prognosis group, and Spearman analysis showed that SII and serum GPR were significantly correlated with the admission Glasgow Coma Scale score as well as the NIHSS score and that SII and GPR increased with the increase in mRS score. Multivariate logistic regression analysis showed that admission NIHSS score, hematoma volume SII, GPR, NLR, and PLR were independently associated with poor patient prognosis. Analysis of the subjects' work characteristic curves showed that the areas under the SII, GPR, NLR, PLR, LMR, and coSII-GPR curves were 0.838, 0.837, 0.825, 0.718, 0.616, and 0.883. SII and GRP were significantly associated with disease severity and short-term prognosis in SICH patients 3 months after discharge, and SII and GPR had better predictive value compared with NLR, PLR, and LMR. In addition, coSII-GPR, a joint indicator based on SII and GPR, can improve the predictive accuracy of poor prognosis 3 months after discharge in patients with SICH.

Outward potassium current in neurons of aestivated land snail Achatina fulica.

Aestivation and hibernation represent distinct forms of animal quiescence, characterized by physiological changes, including ion composition. Intracellular ion flows play a pivotal role in eliciting alterations in membrane potential and facilitating cellular communication, while outward K+ currents aid in the restitution and upkeep of the resting membrane potential. This study explores the relationship between inward and outward currents during aestivation in Achatina fulica snails. Specimens were collected near MSUBIT University in Shenzhen and divided into two groups. The first group was kept on a lattice diet, while the second one consisted of aestivating individuals, that were deprived of food and water until a cork-like structure sealed their shells. Recording of current from isolated neurons were conducted using the single-electrode voltage clamp mode with an AxoPatch 200B amplifier. Electrophysiological recordings on pedal ganglia neurons revealed significant differences in the inactivation processes of the Ia and Ikdr components. Alterations in the Ikdr component may inhibit pacemaker activity in pedal ganglion neurons, potentially contributing to locomotion cessation in aestivated animals. The KS current remains unaffected during aestivation. Changes in slow K+ current components could disrupt the resting membrane potential, possibly leading to cell depolarization and influx of Ca2+ and Na+ ions, impacting cell homeostasis. Thus, maintaining the constancy of outward K+ current is essential for cell stability.

Endurance Training Improves Leg Proton Release and Decreases Potassium Release During High-Intensity Exercise in Normoxia and Hypobaric Hypoxia.

AIM: To assess the impact of endurance training on skeletal muscle release of H+ and K+. METHODS: Nine participants performed one-legged knee extension endurance training at moderate and high intensities (70%-85% of Wpeak), three to four sessions·week-1 for 6 weeks. Post-training, the trained and untrained (control) leg performed two-legged knee extension at low, moderate, and high intensities (40%, 62%, and 83% of Wpeak) in normoxia and hypoxia (~4000 m). The legs were exercised simultaneously to ensure identical arterial inflow concentrations of ions and metabolites, and identical power output was controlled by visual feedback. Leg blood flow was measured (ultrasound Doppler), and acid-base variables, lactate- and K+ concentrations were assessed in arterial and femoral venous blood to study K+ and H+ release. Ion transporter abundances were assessed in muscle biopsies. RESULTS: Lactate-dependent H+ release was similar in hypoxia to normoxia (p = 0.168) and was lower in the trained than the control leg at low-moderate intensities (p = 0.060-0.006) but similar during high-intensity exercise. Lactate-independent and total H+ releases were higher in hypoxia (p < 0.05) and increased more with power output in the trained leg (leg-by-power output interactions: p = 0.02). K+ release was similar at low intensity but lower in the trained leg during high-intensity exercise in normoxia (p = 0.024) and hypoxia (p = 0.007). The trained leg had higher abundances of Na+/H+ exchanger 1 (p = 0.047) and Na+/K+ pump subunit α (p = 0.036). CONCLUSION: Moderate- to high-intensity endurance training increases lactate-independent H+ release and reduces K+ release during high-intensity exercise, coinciding with increased Na+/H+ exchanger 1 and Na+/K+ pump subunit α muscle abundances.

Serum macroelements and microelements levels in periparturient dairy cows in relation to fatty liver diseases.

BACKGROUND: Fatty liver in dairy cows is a common metabolic disease defined by triglyceride (TG) buildup in the hepatocyte. Clinical diagnosis of fatty liver is usually done by liver biopsy, causing considerable economic losses in the dairy industry owing to the lack of more effective diagnostic methods. Therefore, this study aimed to investigate the potential utility of blood biomarkers for the diagnosis and early warning of fatty liver in dairy cows. RESULTS: A total of twenty-four lactating cows within 28 days after parturition were randomly selected as experimental animals and divided into healthy cows (liver biopsy tested, n = 12) and cows with fatty liver (liver biopsy tested, n = 12). Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the macroelements and microelements in the serum of two groups of cows. Compared to healthy cows (C), concentrations of calcium (Ca), potassium (K), magnesium (Mg), strontium (Sr), selenium (Se), manganese (Mn), boron (B) and molybdenum (Mo) were lower and copper (Cu) was higher in fatty liver cows (F). Meanwhile, the observed differences in macroelements and microelements were related to delivery time, with the greatest major disparity between C and F occurring 7 days after delivery. Multivariable analysis was used to test the correlation between nine serum macroelements, microelements and fatty liver. Based on variable importance projection and receiver operating characteristic (ROC) curve analysis, minerals Ca, Se, K, B and Mo were screened as the best diagnostic indicators of fatty liver in postpartum cows. CONCLUSIONS: Our data suggested that serum levels of Ca, K, Mg, Se, B, Mo, Mn, and Sr were lower in F than in C. The most suitable period for an early-warning identification of fatty liver in cows was 7 days after delivery, and Ca, Se, K, B and Mo were the best diagnostic indicators of fatty liver in postpartum cows.

Sodium-glucose cotransporter-2 inhibitors and abnormal serum potassium: a real-world, pharmacovigilance study.

BACKGROUND: New trials indicated a potential of sodium-glucose cotransporter-2 inhibitors (SGLT2i) to reduce hyperkalemia, which might have important clinical implications, but real-world data are limited. Therefore, we examined the effect of SGLT2i on hyper- and hypokalemia occurrence using the FDA adverse event reporting system (FAERS). METHODS: The FAERS database was retrospectively queried from 2004q1 to 2021q3. Disproportionality analyses were performed based on the reporting odds ratio (ROR) and 95% confidence interval (CI). RESULTS: There were 84 601 adverse event reports for SGLT2i and 1 321 186 reports for other glucose-lowering medications. The hyperkalemia reporting incidence was significantly lower with SGLT2i than with other glucose-lowering medications (ROR, 0.83; 95% CI, 0.79-0.86). Reductions in hyperkalemia reports did not change across a series of sensitivity analyses. Compared with that with renin-angiotensin-aldosterone system inhibitors (RAASi) alone (ROR, 4.40; 95% CI, 4.31-4.49), the hyperkalemia reporting incidence was disproportionally lower among individuals using RAASi with SGLT2i (ROR, 3.25; 95% CI, 3.06-3.45). Compared with that with mineralocorticoid receptor antagonists (MRAs) alone, the hyperkalemia reporting incidence was also slightly lower among individuals using MRAs with SGLT-2i. The reporting incidence of hypokalemia was lower with SGLT2i than with other antihyperglycemic agents (ROR, 0.79; 95% CI, 0.75-0.83). CONCLUSION: In a real-world setting, hyperkalemia and hypokalemia were robustly and consistently reported less frequently with SGLT2i than with other diabetes medications. There were disproportionally fewer hyperkalemia reports among those using SGLT-2is with RAASi or MRAs than among those using RAASi or MRAs alone.

Spatiotemporal patterns of leaf nutrients of wild apples in a wild fruit forest plot in the Ili Valley, China.

Malus sieversii, commonly known as wild apples, represents a Tertiary relict plant species and serves as the progenitor of globally cultivated apple varieties. Unfortunately, wild apple populations are facing significant degradation in localized areas due to a myriad of factors. To gain a comprehensive understanding of the nutrient status and spatiotemporal variations of M. sieversii, green leaves were collected in May and July, and the fallen leaves were collected in October. The concentrations of leaf nitrogen (N), phosphorus (P), and potassium (K) were measured, and the stoichiometric ratios as well as nutrient resorption efficiencies were calculated. The study also explored the relative contributions of soil, topographic, and biotic factors to the variation in nutrient traits. The results indicate that as the growing period progressed, the concentrations of N and P in the leaves significantly decreased (P < 0.05), and the concentration of K in October was significantly lower than in May and July. Throughout plant growth, leaf N-P and N-K exhibited hyperallometric relationships, while P-K showed an isometric relationship. Resorption efficiency followed the order of N < P < K (P < 0.05), with all three ratios being less than 1; this indicates that the order of nutrient limitation is K > P > N. The resorption efficiencies were mainly regulated by nutrient concentrations in fallen leaves. A robust spatial dependence was observed in leaf nutrient concentrations during all periods (70.1-97.9% for structural variation), highlighting that structural variation, rather than random factors, dominated the spatial variation. Nutrient resorption efficiencies (NRE, PRE, and KRE) displayed moderate structural variation (30.2-66.8%). The spatial patterns of nutrient traits varied across growth periods, indicating they are influenced by multifactorial elements (in which, soil property showed the highest influence). In conclusion, wild apples manifested differentiated spatiotemporal variability and influencing factors across various leaf nutrient traits. These results provide crucial insights into the spatiotemporal patterns and influencing factors of leaf nutrient traits of M. sieversii at the permanent plot scale for the first time. This work is of great significance for the ecosystem restoration and sustainable management of degrading wild fruit forests.

Association between the hypokalaemia index based on area over the serum potassium concentration curve and occurrence of acute kidney injury in patients administered liposomal amphotericin B.

BACKGROUND: Acute kidney injury (AKI) and hypokalaemia are common adverse events after treatment with liposomal amphotericin B (L-AMB). OBJECTIVES: Because excess potassium (K) leakage occurs during renal tubular injury caused by L-AMB, measuring the decrease in rate of serum K concentration might be more useful to assess the renal impact of L-AMB than hypokalaemia identified from a one-point measurement. The effects of a decrease in K concentration and duration of hypokalaemia on AKI were investigated. METHODS: A ≥ 10% decrease in K concentration from the reference concentration within a 7-day timeframe was evaluated. The hypokalaemia index, which combines the duration of K concentration lower than the reference and a marked low K concentration, was calculated from the area over the concentration curve. RESULTS: Eighty-six patients were included in the study. The incidences of AKI and decrease in K concentration were 36.0% and 63.9%, respectively. Of patients who developed both adverse events, a decrease in K concentration occurred first in 22 of 26 patients, followed by AKI 7 days later. Hypokalaemia did not increase AKI risk whereas a decrease in K concentration was an independent risk factor for AKI. The hypokalaemia index in patients with AKI was significantly higher than those without AKI (5.35 vs. 2.50 points, p = 0.002), and ≥3.45 points was a significant predictor for AKI. CONCLUSION: A ≥ 10% decrease in the K concentration was a significant factor for AKI in patients receiving L-AMB therapy. In such patients, dose reduction or alternative antifungals could be considered based on the hypokalaemia index.

Associations between dietary potassium intake and urinary potassium excretion: a protocol for systematic review and meta-analysis.

BACKGROUND: While numerous studies have reported associations between low dietary potassium intake and adverse clinical outcomes, methods to estimate potassium intake, mainly self-reported dietary measures and urinary potassium excretion, entail certain limitations. Self-reported measures are subject to underreporting and overreporting. Urinary potassium excretion is affected by multiple factors including renal function. Revealing the degree of bias inherent in these measures would help accurately assess potassium intake and its association with disease risk. We aim to summarize evidence on the strength of the associations between potassium intake estimated from 24-h urinary potassium excretion and potassium intake estimated from self-reported dietary measures or objective quantification methods in populations with different kidney function levels and age groups. We also aim to identify factors that affect the association strength. METHODS: We will search for potentially eligible studies that examined associations between self-reported potassium intake, 24-h urinary potassium excretion, and objectively quantified potassium intake, using MEDLINE (PubMed), Embase, Web of Science, and Scopus. Studies on children, adolescents, adults, and the elderly are eligible. Studies of patients on dialysis will be excluded. Collective study results, including a meta-analysis, will be synthesized if an adequate number of studies examining similar dietary potassium intake estimation methods are found. Analyses will be performed separately according to age groups and renal function. For the meta-analysis, fixed-effects or random-effect models will be employed depending on the degree of study heterogeneity to combine across studies the correlation coefficient, ratio, or standardized mean difference for potassium intake, comparing dietary potassium intake based on self-reported or objectively quantified methods and intake based on 24-h urinary potassium excretion. The degree of heterogeneity among included studies will be examined by calculating I2 statistics. To investigate sources of study heterogeneity, random-effects meta-regression analyses will be performed. DISCUSSION: Revealing the strength of the association between dietary and urinary measures in populations with different levels of kidney function and age groups will enhance researchers' and clinicians' ability to interpret studies that utilize these measures and help establish a more solid evidence base for the role of potassium intake in changing chronic disease risk. Identifying factors that modify the associations between these measures may aid in developing predictive models to estimate actual potassium intake. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022357847.

Revealing the Mechanism of NLRP3 Inflammatory Pathway Activation through K+ Efflux Induced by PLO via Signal Point Mutations.

Trueperella pyogenes is an important opportunistic pathogenic bacterium widely distributed in the environment. Pyolysin (PLO) is a primary virulence factor of T. pyogenes and capable of lysing many different cells. PLO is a member of the cholesterol-dependent cytolysin (CDC) family of which the primary structure only presents a low level of homology with other members from 31% to 45%. By deeply studying PLO, we can understand the overall pathogenic mechanism of CDC family proteins. This study established a mouse muscle tissue model infected with recombinant PLO (rPLO) and its single-point mutations, rPLO N139K and rPLO F240A, and explored its mechanism of causing inflammatory damage. The inflammatory injury abilities of rPLO N139K and rPLO F240A are significantly reduced compared to rPLO. This study elaborated on the inflammatory mechanism of PLO by examining its unit point mutations in detail. Our data also provide a theoretical basis and practical significance for future research on toxins and bacteria.

Effects of biochar types on seed germination, growth, chlorophyll contents, grain yield, sodium, and potassium uptake by wheat (Triticum aestivum L.) under salt stress.

Soil salinity is a significant challenge in agriculture, particularly in arid and semi-arid regions such as Pakistan, leading to soil degradation and reduced crop yields. The present study assessed the impact of different salinity levels (0, 25, and 50 mmol NaCl) and biochar treatments (control, wheat-straw biochar, rice-husk biochar, and sawdust biochar applied @ 1% w/w) on the germination and growth performance of wheat. Two experiments: a germination study and a pot experiment (grown up to maturity), were performed. The results showed that NaCl-stress negatively impacted the germination parameters, grain, and straw yield, and agronomic and soil parameters. Biochar treatments restored these parameters compared to control (no biochar), but the effects were inconsistent across NaCl levels. Among the different biochars, wheat-straw biochar performed better than rice-husk and sawdust-derived biochar regarding germination and agronomic parameters. Biochar application notably increased soil pHs and electrical conductivity (ECe). Imposing NaCl stress reduced K concentrations in the wheat shoot and grains with concomitant higher Na concentrations in both parts. Parameters like foliar chlorophyll content (a, b, and total), stomatal and sub-stomatal conductance, and transpiration rate were also positively influenced by biochar addition. The study confirmed that biochar, particularly wheat-straw biochar, effectively mitigated the adverse effects of soil salinity, enhancing both soil quality and wheat growth. The study highlighted that biochar application can minimize the negative effects of salinity stress on wheat. Specifically, the types and dosages of biochar have to be optimized for different salinity levels under field conditions.

Chloroplast envelope K+/H+ antiporters are involved in cytosol pH regulation.

Variations in light intensity induce cytosol pH changes in photosynthetic tissues, providing a possible signal to adjust a variety of biochemical, physiological and developmental processes to the energy status of the cells. It was shown that these pH changes are partially due to the transport of protons in or out of the thylakoid lumen. However, the ion transporters in the chloroplast that transmit these pH changes to the cytosol are not known. KEA1 and KEA2 are K+/H+ antiporters in the chloroplast inner envelope that adjust stromal pH in light-to-dark transitions. We previously determined that stromal pH is higher in kea1kea2 mutant cells. In this study, we now show that KEA1 and KEA2 are required to attenuate cytosol pH variations upon sudden light intensity changes in leaf mesophyll cells, showing they are important components of the light-modulated pH signalling module. The kea1kea2 mutant mesophyll cells also have a considerably less negative membrane potential. Membrane potential is dependent on the activity of the plasma membrane proton ATPase and is regulated by secondary ion transporters, mainly potassium channels in the plasma membrane. We did not find significant differences in the activity of the plasma membrane proton pump but found a strongly increased membrane permeability to protons, especially potassium, of the double mutant plasma membranes. Our results indicate that chloroplast envelope K+/H+ antiporters not only affect chloroplast pH but also have a strong impact on cellular ion homeostasis and energization of the plasma membrane.

Mitigating NaCl stress in Vigna radiata L. cultivars using Bacillus pseudomycoides.

Salt stress is one of the significant abiotic stress factors that exert harmful effects on plant growth and yield. In this study, five cultivars of mung bean (Vigna radiata L.) were treated with different concentrations of NaCl and also inoculated with a salt-tolerant bacterial strain to assess their growth and yield. The bacterial strain was isolated from the saline soil of Sahiwal District, Punjab, Pakistan and identified as Bacillus pseudomycoides. Plant growth was monitored at 15-days interval and finally harvested after 120 days at seed set. Both sodium and potassium uptake in above and below-ground parts were assessed using a flame photometer. Fresh and dry mass, number of pods, seeds per plant, weight of seeds per plant and weight of 100 seeds reduced significantly as the concentration of NaCl increased from 3 to 15 dSm-1. There was a significant reduction in the growth and yield of plants exposed to NaCl stress without bacterial inoculum compared to the plants with bacterial inoculum. The latter plants showed a significant increase in the studied parameters. It was found that the cultivar Inqelab mung showed the least reduction in growth and yield traits among the studied cultivars, while Ramzan mung showed the maximum reduction. Among all the cultivars, maximum Na+ uptake occurred in roots, while the least uptake was observed in seeds. The study concludes that NaCl stress significantly reduces the growth and yield of mung bean cultivars, but Bacillus pseudomycoides inoculum alleviates salt stress. These findings will be helpful to cultivate the selected cultivars in soils with varying concentrations of NaCl.

Combined activation of artificial and natural ion channels for disrupting mitochondrial ion homeostasis towards effective postoperative tumor recurrence and metastasis suppression.

Rationale: Pharmacological targeting of mitochondrial ion channels is developing as a new direction in cancer therapy. The opening or closing of these channels can impact mitochondrial function and structure by interfering with intracellular ion homeostasis, thereby regulating cell fate. Nevertheless, their abnormal expression or regulation poses challenges in eliminating cancer cells, and further contributes to metastasis, recurrence, and drug resistance. Methods: We developed an engineered mitochondrial targeted delivery system with self-reinforcing potassium ion (K+) influx via amphiphilic mitochondrial targeting polymer (TMP) as carriers to co-deliver natural K+ channel agonists (Dinitrogen oxide, DZX) and artificial K+ channel molecules (5F8). Results: Using this method, DZX specifically activated natural K+ channels, whereas 5F8 assembled artificial K+ channels on the mitochondrial membrane, leading to mitochondrial K+ influx, as well as oxidative stress and activation of the mitochondrial apoptotic pathway. Conclusion: The synergistic effect of 5F8 and DZX presents greater effectiveness in killing cancer cells than DZX alone, and effectively inhibited tumor recurrence and lung metastasis following surgical resection of breast cancer tumors in animal models. This strategy innovatively integrates antihypertensive drugs with artificial ion channel molecules for the first time to effectively inhibit tumor recurrence and metastasis by disrupting intracellular ion homeostasis, which will provide a novel perspective for postoperative tumor therapy.

Electrical signaling in three-dimensional bacterial biofilms using an agent-based fire-diffuse-fire model.

Agent-based models were used to describe electrical signaling in bacterial biofilms in three dimensions. Specifically, wavefronts of potassium ions in Escherichia coli biofilms subjected to stress from blue light were modeled from experimental data. Electrical signaling occurs only when the biofilms grow beyond a threshold size, which we have shown to vary with the K^{+} ion diffusivity, and the K^{+} ion threshold concentration, which triggered firing in the fire-diffuse-fire model. The transport of the propagating wavefronts shows superdiffusive scaling on time. K^{+} ion diffusivity is the main factor that affects the wavefront velocity. The K^{+} ion diffusivity and the firing threshold also affect the anomalous exponent for the propagation of the wavefront determining whether the wavefront is subdiffusive or superdiffusive. The geometry of the biofilm and its relation to the mean-square displacement (MSD) of the wavefront as a function of time was investigated for spherical, cylindrical, cubical, and mushroom-like structures. The MSD varied significantly with geometry; an additional regime to the kinetics occurred when the potassium wavefront leaves the biofilm. Adding cylindrical defects to the biofilm, which are known to occur in E. coli biofilms, also gave an extra kinetic regime to the wavefront MSD for the propagation through the defect.